FINAL DESIGN CONCEPT REPORT
Interstate-8/Henness Road TRAFFIC INTERCHANGE Tracs No.: 008 PN 176 H7653 01X Federal Aid Sequence: 008-B(AWD) SOUTHCENTRAL DISTRICT - PINAL COUNTY
April 25, 2017 Prepared by: Prepared for:
I-8/Henness Road TI, MP 176 –Final Design Concept Report
List of Acronyms IGA Inter-Governmental Agreement AADT Annual Average Daily Traffic JPA Joint Project Agreement
AASHTO American Association of State Highway and Transportation KHA Kimley-Horn and Associates, Inc. Officials LOS Level of Service ADEQ Arizona Department of Environmental Quality MP Milepost ADOT Arizona Department of Transportation MPH, mph Miles per Hour ADT Average Daily Traffic MUTCD Manual on Uniform Traffic Control Devices AGFD Arizona Game and Fish Department NEPA National Environmental Policy Act APS Arizona Public Service RCBC Reinforced Concrete Box Culvert BLM Bureau of Land Management RDG Roadway Design Guidelines CFR Code of Federal Regulations R/W Right-of-way CGMR Casa Grande Mountain Ranch, LP SPT Standard Penetration Test CIP Capital Improvement Plan SATS Small Area Transportation Study CMP Corrugated Metal Pipe SSD Stopping Sight Distance COAR Change of Access Report T&E Threatened and Endangered DCR Design Concept Report TCE Temporary Construction Easements DPS Department of Public Safety TI Traffic Interchange FAA Federal Aviation Administration USACE United States Army Corps of Engineers FEMA Federal Emergency Management Agency USFWS United States Fish and Wildlife Service FHWA Federal Highway Administration vpd Vehicles Per Day FIRM Flood Insurance Rate Map
HCS Highway Capacity Software
ICO Issues, Concerns, and Opportunities
IDCR Initial Design Concept Report
i I-8/Henness Road TI, MP 176 –Final Design Concept Report
Executive Summary Purpose and Need Estimated Cost – Recommended Alternative Kimley-Horn and Associates, Inc. (KHA) is currently under contract with the The Henness Road TI is a significant component of the City of Casa Grande’s The cost summary for the recommended Alternative is: landowner / developer Casa Grande Mountain Ranch, LP (CGMR) to prepare future roadway system. The TI is a major component of a principal arterial a Design Concept Report (DCR) for the Arizona Department of corridor that is planned to ultimately provide a parallel route on the west side Construction: $ 15,479,500 Transportation (ADOT) for the proposed construction of Henness Road of I-10 from I-8 to Val Vista Boulevard. Without the Henness Road TI on I- Construction Admin & Contingencies: $ 3,065,500 Traffic Interchange (TI) on Interstate 8 (I-8) at milepost (MP) 176. 8, there would be no access to I-8/I-10 between Trekell Road (on I-8) and Utility Relocation: $ 50, 000 Selma Highway (on I-10), a distance of approximately six miles. The TI will Right-of-Way: $ 471,000 ADOT Project No. 008 PN 176 H7653 01X is located on I-8 approximately provide access to landlocked parcels in the northwest quadrant of the existing Design: $ 890,000 one mile west of the existing system interchange between I-8 and I-10 in the I-8 / I-10 system interchange. Total: $ 19,956,000 City of Casa Grande, Pinal County, Arizona. Henness Road currently does Significant areas of developable land are constrained by existing freeway not exist near I-8 but is identified in the 2007 City of Casa Grande Small Area Table ES.1 and Table ES.2 show the comparative cost of the alternatives. Transportation Study (SATS). corridors, rail corridors, and irrigation facilities. Reliance on only two interchanges six miles apart could result in significant congestion and delay Phased Implementation Plan The objective of this DCR is to recommend a preferred alternative for the that can be mitigated with the addition of the Henness Road TI. The design location and construction of Henness Road TI, while also identifying of the interchange will be constrained by the surrounding topography and the Two phases of construction will be implemented for the Henness Road TI: future connectivity to the City of Casa Grande arterial street system, and existing freeway corridors and will be guided by the long-range improvement Interim Phase and Ultimate Phase. developing a design to accommodate future reconstruction of the I-8 / I-10 plans for the I-8 / I-10 system interchange as shown in the ADOT I-10 system interchange by ADOT. Corridor Study from Junction I-8 to Tangerine Road. Interim Phase (this project): Henness Rd TI will be constructed as a compact diamond TI during this interim phase. Construction of the Henness Road TI ADOT completed a corridor study (Interstate 10 Corridor Study, Junction I-8 Design Concept Alternatives will be privately funded. R/W for the TI will be dedicated to ADOT and To Tangerine Road, ADOT Project Number 010 PN 199 H6773 01L (Federal ADOT will be responsible for maintenance of the TI after construction within Project Number NH-010-D(ASM)) for the I-10 corridor from Junction I-8 to The following is a brief description of the alternatives: their access control limits. The City of Casa Grande will be responsible for Tangerine Road. The Final DCR recommended improvements along the I-10 owning and maintaining Henness Road outside of ADOT limits after its No Build Alternative: The No Build Alternative is provided for comparison corridor to accommodate the projected 2030 traffic demand. Reconstruction construction. purposes. Under this alternative, the I-8 corridor would remain in the present of the I-8/I-10 system interchange is included as part of these proposed improvements, however, no construction funds currently exist. condition. Only regular maintenance activities would be conducted. This Henness Rd TI would require connection to the City of Casa Grande alternative provides no improvements to the access, capacity, or operational arterial street system. North of the TI, Henness Road will be extended The Federal Highway Administration (FHWA) is serving as the lead federal characteristics of the existing roadway and involves no cost or change to north to the mid-section line between Selma Highway and Cornman Road agency. FHWA is involved in reviewing and approving change of access on environmental features of the corridor. section lines. Henness Road will be connected to Peart Road to the west I-8 at Henness Road. along this mid-section line. This connector road will be built by the The No Build Alternative would not provide access to I-8/I-10 within a six- developer either prior to or at the same time the Henness Road TI is mile distance from Trekell Road on I-8 to Selma Highway on I-10 and it The right-of-way (R/W) required for the Henness Road TI and Henness Road constructed. Currently, the lands for the proposed connector road are would not support future economic development. Therefore, the No-Build improvements is owned by the CGMR and will be dedicated to ADOT and within Pinal County jurisdiction. CGMR is working with both Pinal Alternative is not recommended for this project. the City of Casa Grande prior to bid advertisement for construction of the County and Casa Grande along with the property owners for right-of-way Henness Road TI. The costs of design and construction will be privately dedication for the connector road. It is expected that the City of Casa funded. ADOT will review all reports and construction documents and Build Alternative (Recommended): The Build Alternative involves construction of the Henness Road TI, consisting of a new Henness Road Grande will annex these lands and will take the ownership and advertise the project for bid and construction. ADOT will administer and maintenance of the connector road. oversee the construction of this project as well as perform all inspection and corridor, a bridge over the I-8 roadway, and four new ramps connecting I-8 to Henness Road. quality assurance/quality control functions during construction. The City of Casa Grande has included this Henness-Peart connector The Build Alternative will encourage future economic growth by providing a roadway in its five-year Capital Improvement Plan (CIP) for the year 2018 new roadway corridor and interstate access. Additionally, a new access point (Project # 18-STR-2575). Pinal County has also included this roadway in to I-8 from the City of Casa Grande roadway network will be provided. For its five-year CIP for budget years 2016-17 (see Appendix J). these reasons, the Build Alternative is the preferred alternative for this project.
ii I-8/Henness Road TI, MP 176 –Final Design Concept Report
Ultimate Phase (future project – not funded): ADOT will reconstruct the I-8 the same time ADOT takes ownership of R/W required for the Henness Road Cornman Road is proposed to extend east and west of Henness Road on the / I-10 system interchange during the ultimate phase as a part of ADOT’s TI. existing Cornman Road alignment to provide access to future surrounding long-range improvements within these corridors. Due to its less than two- development. The existing Lamb Road is proposed to extend east from Peart mile separation from the I-8 / I-10 system interchange, Henness RD TI will Future Roadway Network Road, provide access to Henness Road, and terminate at the existing Cox need to be connected to the I-8 / I-10 system interchange via a pair of Road alignment. collector-distributor (C-D) roads. The future development plan for the area is shown in Figure 5.2. Henness Road is anticipated to extend north and south from the proposed traffic Concurrent Technical Documents CGMR has agreed to deed to ADOT approximately 60 acres of their land for interchange at I-8. North of I-8, Henness Road will extend north as a two-lane future reconstruction of the I-8 / I-10 system interchange (northwest corner) roadway and then continue west to intersect with existing Peart Road. As Concurrent with the DCR, the following documents and reports have been and approximately 35 acres of their lands for future construction of the C-D shown in Figure 6-1: Year 2030 Roadway Improvement Plan of the City of prepared: COAR, Traffic Report, Drainage Report, Bridge Selection Report, roads (between I-10 and Henness Road TI) subject to ADOT/FWHA's final Casa Grande Small Area Transportation Study (SATS), Henness Road is and supportive environmental reports. approval of the Henness Road TI DCR and Change of Access Report anticipated to continue north across the Casa Grande Canal by 2030, providing (COAR), as well as bidding and administering construction of the Henness regional access to Casa Grande via the Henness Road interchange. To the Road TI. In return, ADOT has agreed to take ownership and responsibility to south, Henness Road will terminate at the intersection with the proposed Lamb fund and construct the C-D roads along with the I-8 / I-10 system interchange Road extension. A copy of Figure 6-1 from the SATS is included in when they are needed in the future. CGMR will deed this R/W to ADOT at Appendix I.
Table ES.1 – Estimated Costs for Recommended Alternative
Total Utility Recommended Right-of-Way Begin Station End Station Construction Relocation Design Costs Total Costs Alternative Costs Costs Costs
Henness Road 9+57.00 36+00.00
Ramp A 10+00.00 41+93.41
Ramp B 10+00.00 30+58.47 $ 18,545,000 $50,000 $471,000 $890,000 $ 19,956,000
Ramp C 10+00.00 45+60.58
Ramp D 10+00.00 34+09.43
Total
Table ES.2 – Estimated Costs for Other Alternatives
Total Utility Right-of-Way Alternative Construction Relocation Total Costs Costs Costs Costs No Build $0 $0 $0 $0
iii I-8/Henness Road TI, MP 176 –Final Design Concept Report
3.9 Clear Zone ...... 11 5.15 Pavement Design ...... 19 Table of Contents 3.10 Barrier Runout Length ...... 12 5.16 Design Exceptions/Variances ...... 19 List of Acronyms ...... i 3.11 Slopes ...... 12 5.17 Joint Project Agreements ...... 19 3.12 Access Control...... 12 5.18 Implementation ...... 19 Executive Summary ...... ii 3.13 Pavement Structural Section ...... 13 5.19 Future Street Network ...... 20 3.14 Earthwork ...... 13 1.0 Introduction ...... 1 3.15 Right-of-Way ...... 13 6.0 Social, Economic, and Environmental Concerns ...... 23 1.1 Foreword ...... 1 3.16 Fencing ...... 13 6.1 Summary of Physical and Natural Environment ...... 23 1.2 Need for the Project ...... 1 3.17 Structures...... 13 6.2 Cultural Resources/Section 4(f) Properties ...... 23 1.3 Project Objectives ...... 3 3.18 Drainage ...... 13 6.3 Conclusions ...... 24 1.3.1 The Scoping Process...... 3 4.0 Design Concept Alternatives ...... 14 1.3.2 Issues, Concerns, and Opportunities ...... 3 7.0 Opinion of Probable Cost Estimate ...... 25 1.3.3 Measures to Address ICOs ...... 3 4.1 Introduction ...... 14 7.1 Construction Costs and Assumptions ...... 25 1.4 Characteristics of Corridor ...... 3 4.2 Study Sections ...... 14 1.4.1 Existing Roadway ...... 3 4.3 Conditions and Factors Impacting Alternative Development ...14 1.4.2 Existing Right-of-Way ...... 3 4.4 Typical Sections ...... 14 1.4.3 Drainage Characteristics ...... 3 4.5 Design Concept Alternatives Studied ...... 14 1.4.4 Topography ...... 4 4.5.1 No-Build Alternative (Not Recommended) ...... 14 1.4.5 Land Use and Ownership...... 4 4.5.2 Build Alternative (Recommended) ...... 14 1.5 Description of the Project...... 4 4.6 Evaluation of Alternatives ...... 14 1.5.1 Project Length and Termini ...... 7 4.7 Conclusion ...... 14 1.5.2 Typical Section and Lane Configuration ...... 7 1.5.3 New Right-of-Way ...... 7 5.0 Major Design Features of the Recommended Alternative . 16 1.5.4 Incidental Improvements ...... 8 5.1 Introduction ...... 16 1.5.5 Safety Improvements ...... 8 5.2 Typical Sections and Median Widths ...... 16 1.5.6 Drainage Improvements...... 8 5.3 Horizontal and Vertical Alignments ...... 16 1.5.7 Utility and Railroad Improvements and Conflicts ...... 8 5.4 Access ...... 16 1.5.8 Traffic Control ...... 8 5.4.1 Access Control ...... 17 1.5.9 Structures ...... 8 5.5 Right-of-Way ...... 17 5.6 Drainage ...... 17 2.0 Traffic and Crash Data ...... 9 5.6.1 Existing Culverts and Bridges ...... 17 5.6.2 Drainage Requirements and Recommended Improvements 17 3.0 Controlling Design Criteria ...... 10 5.7 Section 404 of the Clean Water Act ...... 18 3.1 Introduction ...... 10 5.8 Earthwork ...... 18 3.2 General Considerations ...... 10 5.9 Geotechnical ...... 18 3.3 Design Speed ...... 10 5.10 Constructability and Traffic Control...... 18 3.4 Lane and Shoulder Widths ...... 10 5.11 Intersections ...... 18 3.5 Horizontal Alignment ...... 10 5.12 Utilities ...... 19 3.6 Vertical Alignment and Stopping Sight Distance ...... 11 5.13 Railroads ...... 19 3.7 Cross Slopes ...... 11 5.14 Structures...... 19 3.8 Vertical Clearance ...... 11
iv I-8/Henness Road TI, MP 176 –Final Design Concept Report
List of Figures Table 5.6 – Proposed Bridge Summary ...... 19
Figure 1.1 – Vicinity Map ...... 2 Figure 1.2 – Proposed Henness Road Traffic Interchange ...... 5 List of Appendices Figure 1.3 – Henness Road Traffic Interchange Right-of-Way ...... 6 Figure 5.1 – Henness Road Traffic Interchange Design ...... 21 A – Change of Access Report Figure 5.2 – Henness Road Traffic Interchange with Future B – Typical Sections and Plan Sheets (Recommended Alternative) Connections ...... 22 C – Cost Estimate (Recommended Alternative) D – Soil Survey E – Traffic Report and Addendum F – Drainage Report List of Tables G – Bridge Selection Report H – I-8 / I-10 system interchange - Preferred Alternative Table ES.1 – Estimated Costs for Recommended Alternative ...... iii I – Figure 6-1 2007 City of Casa Grande SATS Table ES.2 – Estimated Costs for Other Alternatives ...... iii J – Henness-Peart Road Connector - City of Casa Grande and Pinal Table 1.1 – I-8 Posted Speed...... 1 County CIP Table 1.2 – Previous Projects within the Study Area ...... 3 K – Design Variance Approval Table 1.3 – Parcels and Property Owners ...... 4 Table 1.4 – Centerpoint of the Southwest 2025 Ultimate Roadway Network Land Use Assumption ...... 4 Table 1.5 – Centerpoint of the Southwest 2030 Ultimate Roadway Network Land Use Assumption ...... 4 Table 1.6 – Parcels and Property Owners ...... 7 Table 3.1 – Design Speed ...... 10 Table 3.2 – Lane and Shoulder Widths...... 10 Table 3.3 – Shoulder Width Tapers ...... 10 Table 3.4 – Horizontal Alignment ...... 10 Table 3.5 – Vertical Alignment and Stopping Sight Distance ...... 11 Table 3.6 – Vertical Clearance ...... 11 Table 3.7 – Clear Zone ...... 12 Table 3.8 – Barrier Runout Length...... 12 Table 3.9 – Slopes ...... 12 Table 3.10 – Access Control ...... 12 Table 3.11 – Pavement Structural Section ...... 13 Table 3.12 – Bridge Evaluation Summary ...... 13 Table 4.1 – Alternative Evaluation Matrix ...... 15 Table 5.1 – Summary of Existing Culverts ...... 17 Table 5.2 – Summary of Proposed Flows at Culverts ...... 17 Table 5.3 – Earthwork Summary ...... 18 Table 5.4 – Lane Geometry Proposed at Intersections ...... 19 Table 5.5 – Utility Contacts ...... 19
v I-8/Henness Road TI, MP 176 –Final Design Concept Report
1.0 Introduction within the typical 20-year planning horizon. The proposed Henness The objective of this DCR is to recommend a preferred alternative for Road TI improvements will be designed to accommodate the future the location and construction of the Henness Road TI which will provide 1.1 Foreword long-range improvements (bridge lengths and cross-street profiles) future connectivity to the City of Casa Grande arterial street system, identified by ADOT. provide access to landlocked parcels in the northwest quadrant of the Project TRACS # 008 PN 176 H7653 01X is a Design Concept Report existing I-8 / I-10 system interchange, and accommodate future (DCR) with supporting analysis to determine a recommended access The preferred alternative from the ADOT I-10 Corridor Study envisions reconstruction of the I-8 / I-10 system interchange and I-8 widening. location for a new Traffic Interchange (TI) at Henness Road on I-8 a major re-configuration of the existing ramp connections between I-8 within the City of Casa Grande in Pinal County, Arizona. In response to and I-10 along with new collector and distributor (C-D) road connections Currently, no major traffic generators exist near the proposed Henness a request by landowner Casa Grande Mountain Ranch, LP (CGMR), the between Sunland Gin Road and the proposed Henness Road TI. Most Road TI. However, the CGMR plans to develop the land adjacent to the Arizona Department of Transportation (ADOT) is reviewing documents the proposed ramp improvements on the west side of the Henness Road TI into a major retail, industrial, and commercial center. The future pertaining to this TI, which will be designed and constructed per ADOT TI (westbound I-8 on-ramp and eastbound I-8 off-ramp) could be Centerpoint of the Southwest development will occupy a large portion of standards. The Henness Road typical section will be designed per the constructed in advance of the long-range improvements for the I-8 / I-10 the area surrounding the proposed Henness Road TI. City of Casa Grande Principal Arterial as shown in the City’s 2007 system interchange. Under the preferred alternative for the long-range Small Area Transportation Study (SATS). improvements, ramp connections on the east side of the Henness Road The posted speed on I-8 where the Henness Road ramps will tie in is TI (westbound I-8 off-ramp and eastbound I-8 on-ramp) are provided shown in Table 1.1. A project vicinity map is shown in Figure 1.1 on page 2. The through future C-D road connections between Sunland Gin Road and the improvements for the TI will generally be in the northeast quarter of proposed Henness Road TI. These C-D road connections cannot be Table 1.1 – I-8 Posted Speed Section 10 in Township 7 South, Range 6 East of the Gila and Salt River implemented prior to the re-configuration of the existing ramp Baseline & Meridian. connections between I-8 and I-10. MP Speed
The proposed interchange is located approximately one mile west of the Implementing only the portions of the Henness Road TI that can be MP 174 – MP 178 EB 75 mph existing I-8 / I-10 system interchange. Henness Road does not currently constructed in advance of the long-range improvements for the I-8 / I-10 MP 174 – MP 178 WB 75 mph exist near I-8 but is included in the Future Roadway Functional system interchange would result in a half-diamond interchange Classification Plan, along with the Henness Road TI, identified in the configuration limited to westbound I-8 on-ramp and eastbound I-8 off- 1.2 Need for the Project City of Casa Grande SATS. Figure 1.1 shows the project area. Previous ramp connections. To avoid the half-diamond interchange configuration, planning in the area by ADOT has developed a preferred alternative for initial construction of the direct westbound I-8 off-ramp and eastbound I- The Henness Road TI is a significant component of the City of Casa the long-range improvements along I-10 and around the future I-8 / I-10 8 on-ramp connections along with the westbound I-8 on-ramp and Grande’s future roadway system. The TI is a major component of a system interchange. The preferred alternative for I-10/I-8 Interchange is eastbound I-8 off-ramp connections on the west side of the Henness principal arterial corridor that is planned to ultimately provide a parallel provided in Appendix H. Road TI are being proposed in this DCR. The initial direct ramp route on the west side of I-10 from I-8 to Val Vista Boulevard. Without connections on the east side of the TI would be replaced with the C-D the Henness Road TI on I-8, there would be no access to I-8/I-10 The preferred alternative exhibit from the ADOT I-10 Corridor Study, road connections between Sunland Gin Road and the proposed Henness between Trekell Road (on I-8) and Selma Highway (on I-10), Junction I-8 to Tangerine Road, Casa Grande to Tucson Highway, Road TI when the long-range improvements are constructed by ADOT. approximately six miles. ADOT Project Number 010 PN 199 H6773 01L (Federal Project Number NH-010-D(ASM)) completed by AECOM, shows the future The improvements will be constructed in two phases. Henness Road TI Significant areas of developable land are constrained by existing freeway improvements for the I-8 / I-10 system interchange and the facilities (this DCR) will be constructed as a standard compact diamond TI on I-8 corridors, rail corridors, and irrigation facilities. Reliance on only two anticipated at Henness Road and I-8. The future I-8 and I-10 interchange in the interim phase. In the ultimate phase, ADOT will reconstruct the I- interchanges six miles apart could result in significant congestion and will be located approximately one mile from the proposed I-8 and 8 / I-10 system interchange and construct C-D roads as a part of ADOT’s delay that can be mitigated with the addition of the Henness Road TI. Henness Road TI. The schedule for implementation of the long-range long-range improvements within these corridors. Because of the less The design of the interchange will be constrained by the surrounding improvements along I-10 is currently expected to be beyond the typical than required two-mile separation of the Henness Road TI from the I-8 / topography and the existing freeway corridors and will be guided by the 20-year planning horizon (after 2030). Therefore, no changes, other than I-10 system interchange, C-D roads will be constructed between Sunland long-range improvement plans for the I-8 / I-10 system interchange. improvements associated with the Henness Road TI, are anticipated to be Gin Road and Henness Road during the ultimate phase. constructed along I-8 between the Trekell Road interchange (two miles to the west) and the I-8 / I-10 system interchange (one mile to the east)
1 I-8/Henness Road TI, MP 176 –Final Design Concept Report
LOCATION
Figure 1.1 – Vicinity Map
2 I-8/Henness Road TI, MP 176 –Final Design Concept Report
1.3 Project Objectives § FHWA The proposed improvements should meet current ADOT Roadway Design § City of Casa Grande Guidelines (RDG) and City of Casa Grande design standards as applicable. The Henness Road TI is a significant component of the City of Casa Grande’s future roadway system. The TI will provide access to the north FHWA has been in consultation because a change of access on I-8 is 1.4 Characteristics of Corridor through Peart Road and to the south through Lamb Road. The north and required. Scoping meetings between the stakeholders have been south accesses will require future extensions and developments. The ongoing since 2009. 1.4.1 Existing Roadway Henness Road TI makes these future connections feasible. An agency and public scoping process was completed and an agency I-8 is classified as an interstate highway providing two 12-foot travel In addition, the TI provides access to the landlocked land in the and public scoping meeting was held as part of the environmental lanes in each direction of travel including a 4-foot paved inside northwest quadrant of the I-8 / I-10 system interchange. This land is study process for the new TI. shoulder and a 10-foot paved outside shoulder. The eastbound and planned to be developed contingent upon construction of the Henness westbound portions of the roadway are separated by a 75-foot median. Road TI. A Change of Access Report (COAR) (Appendix A) along with The general elevation of the surrounding area is 1,465 feet. The terrain Methods and Assumptions document has been developed and will be along this section of I-8 is level. The posted speed limit along mainline Providing access to I-8/I-10 between Trekell Road (on I-8) and Selma reviewed and approved by FHWA. In addition, concurrent documents I-8 is 75 MPH. Highway (on I-10), approximately six miles, will serve the travelling include a Traffic Report, a Drainage Report, a Bridge Selection Report public and residents of the area. and environmental documents. There is no existing road on the Henness Road alignment at I-8.
The main objective of this project is to fulfill the need for an access point Final design is anticipated to be completed in fiscal year 2017 and Table 1.2 lists previous projects on I-8 within the project limits along at Henness Road. The Henness Road TI will be designed per ADOT construction is anticipated in fiscal year 2018. with a brief description of each project. standards with Henness Road conforming to City of Casa Grande standards. 1.3.2 Issues, Concerns, and Opportunities Table 1.2 – Previous Projects within the Study Area
Begin End Completion The Henness Road TI will be connected to the City of Casa Grande During the scoping process, the following issues, concerns, and Project No. Description arterial street system via extending Henness Road to the existing Peart opportunities (ICOs) were identified: MP MP Date Road as shown in Figure 5.2. North of the TI, Henness Road will be I-8 As-Built: Thornton Rd to I-8-2(38) 172.02 174.48 5/13/1966 extended north to the mid-section line between the Selma Highway and § Lack of access on I-8/I-10 between Trekell Road (on I-8) and Treckell Rd Cornman Road section lines. Henness Road will be connected to Peart Selma Highway (on I-10). I-8 As-Built: Treckell Rd to I-8-2-(43) 174.48 177.74 5/20/1966 Road to the west along this mid-section line. § Lack of connectivity and continuity of Henness Road north and I-10 Interchange south of I-8. I-10-4(43) 177.74 I-10 6/03/1974 I-8 As-Built 1.3.1 The Scoping Process § An opportunity to spur development in the area near the I-8 / I- 10 system interchange I-008-B-501 170.03 178.30 6/21/2002 Fog Coat Overlay The design concept study for the Henness Road TI was initiated by CGMR, a local land owner. CGMR intends to develop the land 1.3.3 Measures to Address ICOs 1.4.2 Existing Right-of-Way contingent upon obtaining access to and from I-8. The study is a first step in a public-private partnership that will include constructing a TI Following the review of information collected from the scoping Existing R/W along I-8 is offset 100 feet from the eastbound and at Henness Road on I-8, funded by the developer, as well as process, the following measures were implemented in the study: westbound construction centerlines. No R/W exists along the proposed connecting the TI to the City of Casa Grande arterial street network. Henness Road alignment. ADOT will reconstruct the I-8 / I-10 system interchange and construct § Construct a TI at Henness Road on I-8. C-D roads from the I-10 / Sunland Jin Road to the I-8 /Henness Road § Provide access to land north and south of I-8 to make 1.4.3 Drainage Characteristics TI in the future. development feasible. § Identify connections to the north and south of the new Henness The drainage area contributing to the project area originates in a steep, The following stakeholders are involved with the project: Road TI. mountainous area to the south that flattens to a milder slope near I-8. The off-site watershed generally consists of undeveloped upland § Identify future C-D road connections to the Henness Road TI. § CGMR rangeland. Off-site runoff flows from south to north mostly in natural § ADOT
3 I-8/Henness Road TI, MP 176 –Final Design Concept Report
washes and is conveyed under I-8 in culverts. A summary of these Table 1.3 – Parcels and Property Owners Table 1.4 – Centerpoint of the Southwest 2025 Ultimate Roadway existing culverts is provided in Section 5.6.1. Network Land Use Assumption Parcel Owner Land Type Number No FEMA floodplains are located within the project area; therefore, ITE Land Use Quantity Units Code impacts to FEMA floodplains were not considered for this project. TANG DARRYL & MAE Vacant Land / Non-Profit 51130002B REVOCABLE TRUST Imp 1.4.4 Topography Single-Family Detached 210 1,746 Units CASA GRANDE MOUNTAIN 51122010B Ag Land School 522 1,000 Students The project lies within the basin and range physiographic province of RANCH LTD PSHIP Arizona. This landform division typically exhibits northwest-trending Light Industrial 110 816,000 SF Vacant Land / Non-Profit mountains, separated by sediment-laden grabens. 51130001A SANCHEZ JULIAN J Imp Business Park 770 126,200 SF The study area is located north of the Casa Grande Mountain Range. Vacant Land / Non-Profit 51130002D LS PARTNERS The area has a gradient to the north and all washes across and in the Imp Corporate Headquarters 714 340,500 SF vicinity of the project flow in this general direction toward the Gila River. CASA GRANDE MOUNTAIN Vacant Land / Non-Profit Shopping Center 820 54,000 SF 511210150 RANCH LTD PSHIP Imp The soil characteristics are provided in a Soil Survey provided in Table 1.5 – Centerpoint of the Southwest 2030 Ultimate Roadway CASA GRANDE MOUNTAIN Vacant Land / Non-Profit Appendix D. 511310020 RANCH LTD PSHIP Imp Network Land Use Assumption
1.4.5 Land Use and Ownership Vacant Land / Non-Profit ITE 511310030 SANCHEZ JULIAN J Land Use Quantity Units Imp Code The adjacent land is mostly in the City of Casa Grande jurisdiction. The rest of the land falls under the unincorporated areas of Pinal CASA GRANDE MOUNTAIN Vacant Land / Non-Profit Single-Family Detached 210 1,796 Units 511310050 County. RANCH LTD PSHIP Imp Apartments 220 709 Units CASA GRANDE MOUNTAIN The land adjacent to the project area is primarily undeveloped. The 511310070 Rental Residential land immediately located on the northwest, northeast, and southwest RANCH LTD PSHIP Resort Hotel 330 200 Rooms corners of the future I-8/Henness Rd TI is zoned for CASA GRANDE MOUNTAIN Vacant Land / Non-Profit 511190320 School 522 1,000 Students commercial/business land uses. A large majority of the frontage along RANCH LTD PSHIP Imp I-8 and I-10 within the study area is zoned for commercial/business Light Industrial 110 2,775,000 SF CASA GRANDE MOUNTAIN Vacant Land / Non-Profit land uses with the exception of the area immediately east of I-10 511310040 between Cornman Road and Arica Road, which is zoned for RANCH LTD PSHIP Imp Business Park 770 1,855,000 SF manufacturing/industrial land uses. To the north and south of the Corporate Headquarters 714 340,500 SF business/commercial areas, land use within the study area is primarily The Centerpoint of the Southwest development site is currently residential with small pockets of manufacturing/industrial and rural proposed as a mixed-use development with single- and multi-family General Office 710 178,000 SF zoning. residential, retail, business park, light industrial, and elementary school land uses. The land use assumptions for the Centerpoint of the Shopping Center 820 209,000 SF Table 1.3 lists parcels adjacent to the proposed TI, property owners, Southwest development under an interim 2025 planning year and a full Specialty Retail 814 82,000 SF and the property type per the Pinal County Assessor’s database. The buildout 2030 planning year are shown in Table 1.4 and Table 1.5, parcels are shown in Figure 1.3. respectively: 1.5 Description of the Project
The basic layout of the project is shown in Figure 1.2.
4 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Figure 1.2 – Proposed Henness Road Traffic Interchange
5 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Figure 1.3 – Henness Road Traffic Interchange Right-of-Way
6 I-8/Henness Road TI, MP 176 –Final Design Concept Report
1.5.1 Project Length and Termini be located 8 feet from the back of the sidewalk, and 6:1 slopes will be New R/W needed along Ramp B varies from the existing R/W of 80 provided to the existing ground. feet offset from the Ramp B centerline to a maximum of 120 feet offset The project will construct a new compact diamond TI with a bridge from the Ramp B centerline. over I-8 at the Henness Road alignment and on- and off-ramps to I-8 in Ramp A is a taper type ramp beginning at westbound I-8 with one 12- both directions. foot travel lane, an 8-foot left shoulder and a 2-foot right shoulder. New R/W needed along Ramp C varies from a maximum of 217 feet Ramp A will taper to include a second 12-foot travel lane with a 2-foot to a minimum of 115 feet offset from the Ramp C centerline. The project length extends from the beginning of Ramp A at left shoulder. westbound I-8 station 3121+50 (MP 176.03) to the end of Ramp C at New R/W needed along Ramp D varies from a maximum of 228 feet eastbound I-8 station 3330+00 (MP 177.28). A station equation exists Ramp B is a taper type ramp beginning at eastbound I-8 with one 12- to a minimum of 105 feet offset from the Ramp D centerline. on eastbound I-8 between stations 3148+38 and 3291+15. A station foot lane, an 8-foot right shoulder, and a 2-foot left shoulder. Ramp B equation exists on westbound I-8 between stations 3149+72 and will taper to include a total of three 12-foot travel lanes, a 2-foot left New R/W needed along Henness Road varies from minimum values of 3291+15. The total project length along I-8 is 6,575 feet or shoulder, and a 2-foot right shoulder. 115 feet south of the bridge and 120 feet north of the bridge to approximately 1.2 miles. maximum values of 230 feet south of the bridge and 310 feet north of Ramp C is a taper type ramp beginning at Henness Road with three 12- the bridge. Construction on Henness Road begins at station 9+57 and ends at foot travel lanes, a 2-foot left shoulder, and a 2-foot right shoulder. station 36+00.00, for a total length of 2,644 feet. Ramp C will taper to two 12-foot travel lane, a 2-foot left shoulder, and Table 1.6 shows the R/W acquisition requirements for each parcel. a 2-foot right shoulder. At the back of gore the ramp tapers down to Construction on Ramp A begins at station 10+00.00, which is one 12-foot travel lane, a 2-foot left shoulder and an 8-foot right Table 1.6 – Parcels and Property Owners equivalent to westbound I-8 station 3121+50 (MP 176.03) and shoulder. R/W Parcel Parcel terminates at station 41+93.41, for a total length of 3,193.41 feet. Owner Needed Number Area Ramp D is a taper type ramp beginning at Henness Road with four 12- for TI Construction on Ramp B begins at station 10+00.00, which is foot travel lanes, a 2-foot left shoulder, and a 2-foot right shoulder. TANG DARRYL & MAE 66.5 equivalent to eastbound I-8 station 3131+00 (MP 176.21), and 51130002B 8.2 Acres Ramp D will taper to one 12-foot travel lane, an 8-foot left shoulder, REVOCABLE TRUST Acres terminates at station 30+58.47, for a total length of 2,058.47 feet. and a 2-foot right shoulder. 15.0 51130001A SANCHEZ JULIAN J 2.3 Acres Construction on Ramp C begins from Henness Road at station All ramps will be designed to provide ADOT standard C-02.10 slopes. Acres 10+00.00 and terminates at station 45+60.58, which is equivalent to 27.4 eastbound I-8 station 3330+00 (MP 177.28), for a total length of 1.5.3 New Right-of-Way 51130002D LS PARTNERS 11.9 Acres 3,560.58 feet. Acres Approximately 31 acres of new R/W will be required as part of this CASA GRANDE MOUNTAIN 40.0 Construction on Ramp D begins from Henness Road at station project for the Henness Road TI. R/W needed for future collector- 511310020 3.0 Acres RANCH LTD PSHIP Acres 10+00.00 and terminates at station 34+09.43, which is equivalent to distributor roads (C-D roads) is approximately 35 acres. R/W westbound I-8 station 3318+50 (MP 177.06), for a total length of ownership will be transferred to ADOT through a Joint Project 26.3 511310030 SANCHEZ JULIAN J 4.48 Acres 2,409.43 feet. Agreement (JPA) prior to bid advertisement for the construction of the Acres new TI. A portion of the existing ADOT R/W on the south side of I-8 CASA GRANDE MOUNTAIN 160.0 1.5.2 Typical Section and Lane Configuration designated for a rest area is needed for the TI but it not included in the 511310050 0.01 Acres RANCH LTD PSHIP Acres new R/W acquisitions. It is anticipated that this R/W will be available Henness Road consists of three 12-foot travel lanes in each direction for the TI construction. CASA GRANDE MOUNTAIN 145.8 511310070 0 Acres separated by a raised concrete median. The concrete median varies RANCH LTD PSHIP Acres between 4 feet at the bridge and 38 feet where there are no turn lanes. New R/W needed along Ramp A varies from a minimum of 85 feet Curb and gutter will be provided on each side of the roadway, and the CASA GRANDE MOUNTAIN 160.0 offset from the Ramp A centerline to a maximum of 115 feet offset 511190320 0 Acres total roadway width from face of curb to face of curb is 124 feet. A 5- from the Ramp A centerline. RANCH LTD PSHIP Acres foot bike lane, measured from the outside travel lane to the face of the CASA GRANDE MOUNTAIN curb, will be provided on both sides of the roadway. A 6-foot sidewalk 511310040 N/A 1.5 Acres RANCH LTD PSHIP will be constructed 5 feet from the back of the curb. A hinge point will
7 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Prior to project bid advertisement, ADOT will take the ownership of 1.5.7 Utility and Railroad Improvements and Conflicts first and direct I-8 traffic through the ramps while the bridge R/W via a JPA executed between CGMR and ADOT. superstructure is constructed in a single phase. No railroad conflicts are anticipated as part of this project. After project construction, ADOT will maintain the Henness Road TI Henness Road and the ramps are new construction and no roadways improvements within their access control limits. Within these limits no Overhead lighting and electrical facilities owned by ADOT exist at the exist beyond I-8; therefore, no impacts to traffic are anticipated. access will be allowed to utilities or any other entities. City of Casa I-8/I-10 interchange to the east of the project. Conflicts are not Grande will provide access to utilities to access their existing and anticipated with these poles or lines. 1.5.9 Structures future facilities beyond the ADOT access control limits. Arizona Water Company has existing waterlines along Lamb Road A new bridge will be constructed as part of this project. The new A JPA will be developed between the ADOT and the City of Casa and Peart Road alignments. No waterlines exist within the project bridge will be constructed over I-8 along Henness Road and span the Grande for the City to maintain Henness Road improvements outside limits. existing I-8 corridor. The new bridge will also accommodate future of the ADOT access control limits. widening of I-8 to six lanes. San Carlos Irrigation Project overhead power lines (12.47 kV) exist 1.5.4 Incidental Improvements along I-8 and may need to be relocated as the lines cross Henness Road close to I-8 south of the ramp intersection. The Henness Road vertical A new 140-foot-wide bridge along Henness Road will be provided profile will be raised over I-8, decreasing the vertical clearance of the spanning over the existing I-8 corridor. This bridge will be designed to power line significantly. accommodate future widening of I-8 to provide three lanes in each direction. APS has no facilities within the project area. SRP has a 500 kV line crossing over the Henness Road alignment just south of the Casa Bike lanes will be provided on Henness Road in both directions. Grande Canal. No conflicts are anticipated.
1.5.5 Safety Improvements No gas lines or telecommunication lines exist in the area. Cox, CenturyLink and Soutwest Gas were contacted to confirm. Currently, vehicles traveling east along I-8 needing access to Casa Grande are required to either use the Trekell Road exit, a paved minor No other utility conflicts are anticipated during construction of the road, or continue to the I-10 interchange. The addition of the Henness Henness Road TI. Road TI will allow another access point from I-8 to Casa Grande, which will lessen the traffic eastbound towards I-10 and improve the 1.5.8 Traffic Control safety of the interchange. Construction of the ramp tie-ins with I-8 will require lane closures. It is 1.5.6 Drainage Improvements anticipated that the closures will be limited to the outside lane.
The proposed drainage improvements for this project consist primarily Traffic will need to be forewarned and/or rerouted for bridge of extending existing culverts along I-8 to maintain existing off-site construction. The majority of the substructure and foundations, drainage patterns. Runoff will continue to be conveyed across I-8 in including the abutment and pier caps, can be built without any major the existing culverts. Existing culverts were evaluated for adequacy closures. However, closures may be required for girder erection and and upgrades were considered and recommended as necessary as part deck and diaphragm concrete pours if the bridge construction happens of the proposed drainage concept. in a single phase.
Additional culverts will be required as part of the future Lamb Road At least one lane of I-8 in each direction during construction of the extension and Henness Road construction. Seven culverts will be bridge can remain open by using one of the following options. The needed to convey runoff underneath the future Lamb Road extension. bridge construction can be phased to allow traffic to use one bound of Two culverts are proposed to convey runoff across Henness Road I-8 by using median crossovers. Another option is to build the ramps north of I-8.
8 I-8/Henness Road TI, MP 176 –Final Design Concept Report
2.0 Traffic and Crash Data The traffic and crash data and analysis is contained in the Traffic Report prepared in concurrence with this DCR. The Traffic Report is provided in Appendix E.
9 I-8/Henness Road TI, MP 176 –Final Design Concept Report
3.0 Controlling Design Criteria ROADWAY DESIGN SPEED HIGHWAY TYPE REFERENCE ROADWAY LANES SHOULDERS REFERENCE
3.1 Introduction 65 MPH at Gore 2’ Left (ramp body) RDG 301.3 50 MPH Ramp Ramp C (EB 8’ Right (ramp body) RDG Table Ramp D (WB Exit) Body Exit Ramps RDG 503.3 12’ There is no existing TI at the Henness Road alignment. The new Henness Entrance) 2’ Left/Right (ramp 302.4 35 MPH Ramp crossroad terminus) RDG 504.5 Road TI and ramps are being designed with minimal impact to existing I-8. Terminus 2’ Left (ramp body) RDG 301.3 The ramp tie-in and gore area will match the existing I-8 elevations at the saw RDG section 503.3 specifies minimum design speed for the crossroad at the interchange Ramp D (WB 8’ Right (ramp body) RDG Table cut lines for a smooth transition. (Henness Road) as 40 mph but not less than the design speed of the crossroad 12’ Exit) 2’ Left/Right (ramp 302.4 approaches to the interchange; the maximum design speed is 50 mph per RDG Table crossroad terminus) RDG 504.5 AASHTO controlling design criteria evaluation is not used since the Henness 101.3. The City of Casa Grande SATS notes a design speed of 55 mph for Principal Road TI is a new TI. The design criteria for the improvements are as follows: Arterials; however, at this time it is felt this speed is higher than necessary – discussions are in progress to seek an exception from the City for a reduced design speed (45 mph as Table 3.3 – Shoulder Width Tapers noted above). These items may change pending further discussions and final 3.2 General Considerations determination of this draft document. NARROW TO WIDER TO ROADWAY REFERENCE WIDER NARROW The design year for the project will be 2030. For design purposes, the terrain 3.4 Lane and Shoulder Widths will be considered level. The design vehicle used will be a WB-67 (interstate – All 15:1 Design Speed:1 RDG 302.5 ramp/crossroad intersections), taken from ADOT Roadway Design Guidelines RDG 505.3 The lane and shoulder widths for Henness Road and the ramps are as shown in RDG Figure 505.3 Turn Lanes 90’ N/A (RDG) Table 407.2. Table 3.2. The shoulder width tapers are shown in Table 3.3. RDG 408.10 and 408.11 3.3 Design Speed Table 3.2 – Lane and Shoulder Widths RDG 505.3 RDG Figure 505.3 Dual Turn Lanes 140’ N/A RDG 408.10 and The design speed for Henness Road and the ramps are shown in Table 3.1. ROADWAY LANES SHOULDERS REFERENCE 408.11 Table 3.1 – Design Speed RDG 301.3 RDG 302.4 3.5 Horizontal Alignment I-8 Mainline 12’ 12’ median, 12’ outside (Future ROADWAY DESIGN SPEED HIGHWAY TYPE REFERENCE Condition) The horizontal alignment criteria for Henness Road and the ramps are shown Controlled Access 14’ Center Turn Lane / I-8 Mainline 75 mph RDG Table 101.3 (2) 12’ Outer City of Casa in Table 3.4. Highways Median Lanes Grande SATS, Henness Road RDG Table 101.3 6’ Bike Lane (from back of 45 mph Arterial Streets Henness Road (1) 14’ Inner Lane Figure 7-2 Table 3.4 – Horizontal Alignment (Principal Arterial) RDG 503.3 curb) (adjacent to RDG Figure 65 MPH at Gore 5’ Bike Lane (from face of 50 MPH Ramp median) 306.4A I-8 RAMPS A, B, HENNESS Ramp A (WB curb) Body Entrance Ramps RDG 503.3 REFERENCE Entrance) RDG 301.3 MAINLINE C, & D ROAD 35 MPH Ramp RDG Table RDG Table Terminus 302.4 8’ Left (ramp body) 2º15’ (70 mph) 202.3D 65 MPH at Gore RDG 504.5 2’ Right (ramp body) (r=2,546.48’) 50 MPH Ramp ADOT MGT Max Degree of 2º00’ (75 (I-8 and Ramp A (WB 2’ Left (ramp crossroad R=1,039’ Ramp B (EB Exit) Body Exit Ramps RDG 503.3 12’ 02-1 Curve mph) 2º30’ (65 mph) Ramps) Entrance) terminus) (Dc=5°30’52.24 35 MPH Ramp AASHTO - or - (r=2,864.7 (r=2,291.83’) 2’ Right (ramp crossroad ”) Terminus Guide for the Min Radius* 9’) 4°30’ (50 mph) AASHTO terminus) 65 MPH at Gore Development of (r=1,273.24’) 2004, Pg 151, 50 MPH Ramp Exhibit 3-16 Ramp C (EB Bicycle Body Entrance Ramps RDG 503.3 Min Degree of Entrance) Facilities (p23) 0°15’ (R=22,920’) N/A RDG 203.2 35 MPH Ramp 2’ Left (ramp body) RDG 301.3 Curve Terminus Ramp B (EB 8’ Right (ramp body) RDG Table Min Central 12’ 2° N/A RDG 203.5 Exit) 2’ Left/Right (ramp 302.4 Angle crossroad terminus) RDG 504.5
10 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Table 3.5 – Vertical Alignment and Stopping Sight Distance 3.8 Vertical Clearance I-8 RAMPS A, B, HENNESS REFERENCE MAINLINE C, & D ROAD I-8 HENNESS The vertical clearance for I-8 under the new Henness Road Bridge is shown in **Low RAMP A, B, C, & D REFERENCE 15 times design Mainline ROAD Table 3.6. speed=300’ speed **High 6.5% on (15x45 mph = RDG 203.5 Table 3.6 – Vertical Clearance 15 times speed=500’ roadway RDG Table 675’) 3% adjacent Min Length of design speed +4%, -5%, ±3% for 204.3 RDG 504.2 to ramp TRAFFIC SIGN Curve (15x75 = Minimum 160’ Max Gradient ±3% 400’ in advance of RDG 408.8 REFERENCE Tangent to termini and STRUCTURES STRUCTURES 1125’) tangent from traffic signals minimum of 100’ RDG 503.5 RDG 503.5 crossroad edge at any leg of past furthest ramp RDG 504.1 RDG, 206.4 of pavement to an Min Vertical curb return * 16’-6” * 18’-0” curve intersection. Clearance Bridge Design 0.4% with curb and gutter; 0.25% without curb and RDG 204.3 Guidelines, 2-7 Max Angle Min Gradient Break w/o RDG 203.5 gutter RDG 504.1 * This is the minimum clearance; however, the ultimate I-8 widening and ≤ 0°45’0” Horizontal 200’ at crossroad reconstruction (including re-profiling) must be accommodated, thus an additional 1’ Curve terminus 3 times or more will be added to the minimum value noted above to accommodate these design speed RDG Table situations. RDG Table Min Vertical 400’ elsewhere, but 1000’ 204.4 202.3D Curve Length in accordance Max with sight (3 x 45 = RDG 504.1 3.9 Clear Zone 0.10’/ft 0.02’/ft Superelevation AASHTO distance 135’) 2012, Table 3- requirements The clear zone criteria are shown in Table 3.7. 13b 50 mph – 425’ Provide tangent of sufficient length to transition 65 mph – 645’ AASHTO Reverse superelevation runoff length for each curve from the 70 mph – 730’ 2012, Table 3- RDG 203.7 Stopping Sight 75 mph – 45 mph – 1 Curves standard location w/o overlapping. Distance 820’ Mainline approaches 360’ Avoid when possible. to exit and entrance RDG 504.1 Ratio of ramps should be 1.5 RDG 503.4 Ratio of successive curves ≤ successive curves x SSD RDG 504.2 Compound 2:1. ≤ 1.5:1. ≤2% at Curves RDG 203.6 Use of simple curves preferred. Use of simple Max Profile ramp/crossroad Break junction, but up to 0.4% ≤ 45 RDG 204.4 curves preferred. 0.2% * Maximum curvature without using a spiral. Without 4% if geometry mph RDG 504.1 ** Upper limit of low speed design is 45 mph; lower limit of high speed design is 50 Vertical Curve requires. 0.2% mph (RDG 101.2). elsewhere. 2% between mainline Avoid broken-back curves (two curves in same direction separated by a short tangent), and ramp up to reverse curves, and compound curves where other options are available. ramp paved gore Maximum nose (parallel-type Ramp Gore 3.6 Vertical Alignment and Stopping Sight Distance N/A ramps only). N/A RDG 504.3 Cross-Slope Breakover 5% between shoulder The vertical alignments criteria and sight distance requirements for Henness and paved gore Road and the ramps are shown in Table 3.5. from gore nose to back of paved gore. Avoid broken-back curves
3.7 Cross Slopes
Cross slopes along Henness Road shall be 2% sloping away from the centerline. Along the ramps, cross slopes shall be 2% sloping away from I-8.
11 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Table 3.7 – Clear Zone ROADWAY/DESIGN FILL SLOPES CUT SLOPES REFERENCE SPEED ROADWAY/DESIGN SPEED RUNOUT LENGTH REFERENCE ROADWAY/DESIGN FILL SLOPES CUT SLOPES REFERENCE SPEED q 50 mph on ramp 20’ 28’ Ramp C (EB entrance ramp) (ADT = 23,000) body 6:1 or 5:1 to 4:1 Where fixed object q 65 mph at gore 330’ Flatter (inclusive) obstructions are q 35 mph at ramp placed on cut 16’ 18’ terminus q 50 mph on ramp body 230’ I-8 Mainline (ADT E/W = 45,181/45,055) backslopes, the recovery area width Ramp D (WB exit ramp) (ADT = 23,257) Ramp D (WB exit ramp) (ADT = 23,257) requirement should meet the recovery q 65 mph at gore 30’ 30’ area indicated by the q 65 mph at gore 330’ fill slope table shown q 50 mph on ramp q 75 mph 30’ 30’ 20’ 28’ q 50 mph on ramp body 230’ utilizing the body foreslope of the cut as the appropriate fill q 35 mph at ramp slope rate. 16’ 18’ 3.11 Slopes terminus Henness Road (ADT = 20,000) Provide maximum The side slopes criterion is shown in Table 3.9. clear zone distance 3.10 Barrier Runout Length possible, but in no Table 3.9 – Slopes q 45 mph 20’ 28’ case less than 1.5’ from face of curb. The barrier design requirements are shown in Table 3.8. I-8 MAINLINE RAMP A, B, C, & D REFERENCE Ramp A (WB entrance ramp) (ADT = Table 3.8 – Barrier Runout Length C-02-10 or C-02-20 C Standards RDG 303.2 C-02-10 5,814) Slopes Series and RDG Figure RDG 306.2 RDG Figure 504.4B 504.4B ROADWAY/DESIGN SPEED RUNOUT LENGTH REFERENCE q 65 mph at gore 30’ 30’ RDG Table 303.2A 3.12 Access Control q 50 mph on ramp 18’ 26’ I-8 Mainline (ADT E/W = 45,181/45,055) body Where fixed object The access control requirements are shown in Table 3.10. obstructions are q 75 mph 415’ q 35 mph at ramp 14’ 16’ placed on cut terminus Table 3.10 – Access Control backslopes, the Henness Road (ADT = 20,000) recovery area width Ramp B (EB exit ramp) (ADT = 12,829) requirement should ACCESS CONTROL q 45 mph 195’ REQUIREMENT REFERENCE meet the recovery LOCATION q 65 mph at gore 30’ 30’ area indicated by the Ramp A (WB entrance ramp) (ADT = 5,814) fill slope table shown q I-8 Mainline, Ramps RDG Table Full access control – no exceptions RDG 104.1 q 50 mph on ramp utilizing the 305.8 A, B, C, and D 20’ 28’ q 65 mph at gore 290’ body foreslope of the cut ** Minimum 300’ from ramp radius. as the appropriate fill Where the 300’ distance ends at q 50 mph on ramp body 190’ q 35 mph at ramp slope rate. different crossroad stations, the access 16’ 18’ terminus q Along crossroad control should be carried to the same RDG 506 Ramp B (EB exit ramp) (ADT = 12,829) station on the crossroad on each side Ramp C (EB entrance ramp) (ADT = with the location farthest along the q 65 mph at gore 330 23,000) crossroad as the control. ** Limits of access control will be established in accordance with approved guidelines. q 50 mph on ramp body 230’ q 65 mph at gore 30’ 30’
12 I-8/Henness Road TI, MP 176 –Final Design Concept Report
3.13 Pavement Structural Section Table 3.12 – Bridge Evaluation Summary o Pavement Drainage - Evaluate per ADOT Highway Drainage Design Manual - Hydraulics (Per FHWA HEC- STRUCTURE The pavement structural sections are shown in Table 3.11. STRUCTURE NO. MILEPOST TYPE 22). LENGTH Table 3.11 – Pavement Structural Section RCB EB & FR 5356 176.64 21’ RCBC RD SURFACE ROADWAY AC AB REFERENCE TREATMENT RCB WB 5357 176.64 21’ RCBC I-8 Mainline - - These sections Source: ADOT State Highway System Bridge Record Henness Road 12” 10” will be updated Ramp A 12” 10” after 3.18 Drainage Ramp B 12” 10” geotechnical Ramp C 12” 10” investigation and materials Drainage design for I-8 shall be in conformance with the ADOT RDG, Ramp D 12” 10” reports Section 600. Drainage design for other roadways shall be in conformance Pavement Design Period = 20 years (RDG 102.1) with Pinal County Drainage Manual, Volumes 1 and 2 (Draft, 2004).
3.14 Earthwork § Drainage Design Frequency: o Allowable Pavement Spread (Henness Road) Shrink/swell factors and over-excavation limits will be per the geotechnical § For 10-year event – minimum one lane. investigation and materials report. o Roadway Conveyance (Henness Road): § 10-year contained within curbs 3.15 Right-of-Way § 100-year contained within R/W and with flow depth The design will need to minimize R/W acquisitions and consider the less than 6 inches at the centerline following ADOT requirements: o Cross-Culverts · 50-year design storm § Provide 10 feet clearance between the toe of a fill slope or outer · With the 100-year flood, water levels should not edge of cut slope rounding and the R/W line (RDG 303.6) significantly increase the flood damage potential on § Provide 5 feet concrete sidewalk detached 5 feet (minimum) from areas outside of ADOT right-of-way. back of curb on crossroad (RDG Figure 306.4C) o Channels and Ditches Hydraulic grade line no higher than subgrade - 50 § Sidewalk on bridge section to be attached per RDG Figure 505.1B; · year event sidewalk outside bridge section to be detached where feasible. § Additional Design Criteria: If R/W is needed: Erosion Control § Minimum Acquisition: 5-foot increments o · Maximum Velocity - Evaluate Erodibility of Native § Preferred Acquisition: 10-foot increments Soil 3.16 Fencing · Minimum Velocity - Evaluate Deposition of Soil · Erosion Control - To be determined per ADOT Fencing shall be Standard C-12 Series (type to be coordinated and Highway Drainage Design Manual - Hydraulics and determined during design). Erosion Control Manual o FEMA Considerations - Evaluate per ADOT RDG, Chapter 3.17 Structures 600, Section 602.1
Existing bridges are summarized below in Table 3.11.
13 I-8/Henness Road TI, MP 176 –Final Design Concept Report
4.0 Design Concept Alternatives Due to these restrictions, only one Build Alternative will be developed and 10 interchange. Therefore, the No-Build Alternative is not recommended for compared to the No-Build Alternative. this project. 4.1 Introduction 4.4 Typical Sections 4.5.2 Build Alternative (Recommended) The purpose of this design concept report is to identify and evaluate alternatives to provide access on I-8 at Henness Road. The recommended The typical section along Henness Road for the Build Alternative consists of The Build Alternative consists of the construction of the Henness Road TI, improvements to the existing highway will involve construction of a new TI. three northbound and three southbound 12-foot travel lanes, separated by a which includes a new Henness Road corridor, a bridge over the existing I- This improvement is intended to address both imminent and long-term needs. raised concrete median, with curb and gutter and a 6-foot concrete sidewalk. 8, and four new ramps connecting I-8 to Henness Road. The achievement of this objective involves determining the best course of The typical section for the ramps is one 12-foot travel lane, a 2-foot outside action based on an evaluation of the issues, concerns, and opportunities. shoulder, and an 8-foot inside shoulder. This alternative will involve future construction and traffic control issues, impacts on existing drainage patterns, and earthwork. The best course of action has been determined through the development and Under the No-Build Alternative, Henness Road and its connecting ramps will analysis of alternatives. Factors considered in the determination of the not be constructed and I-8 will remain unaltered. R/W acquisition will be required as part of this project, but all R/W needs recommended alternative include, but are not limited to: geometrics, use of will be donated by the landowner CGMR to ADOT to help promote future 4.5 Design Concept Alternatives Studied existing roadway, access, R/W requirements, impacts to the environment, economic growth. The costs of construction and design will be privately funded, meaning minimal economic impacts to ADOT. required drainage improvements and associated impacts, utility relocations, Development of alternatives was focused on accommodating the Henness constructability, traffic control, connectivity, and cost. Road TI Bridge in the ultimate I-8 widened condition. Due to the constraints The Build Alternative will help encourage future economic growth by mentioned in Section 4.3, only one build alternative was considered with 4.2 Study Sections providing a new roadway corridor and interstate access. Additionally, a various structure alternatives detailed in the Bridge Selection Report in new access point to I-8 from the City of Casa Grande roadway network The area of study is the I-8 corridor south of the termination of existing Appendix G. will be provided. For these reasons, the Build Alternative is the preferred Henness Road. This is located approximately 1.5 miles west of the I-8/I-10 alternative for this project. The following is a brief description of the alternatives: interchange. 4.6 Evaluation of Alternatives No-Build Alternative: The existing I-8 roadway corridor will remain as it is Two alternatives were considered for this project: a No-Build Alternative and today with no construction improvements. The roadway will remain a Build Alternative. The evaluation of alternatives was based on the issues, concerns, and unchanged. opportunities gathered during the scoping phase and criteria established by the 4.3 Conditions and Factors Impacting Alternative project team. The summary of the evaluation is presented in Table 4.1. The Build Alternative (Recommended): Henness Road will be constructed crossing Development information received at the scoping meetings was reviewed and a list of over the existing I-8 corridor. Four new access ramps will be constructed evaluation factors was developed. Several factors impacted the development of viable alternatives for the project. connecting I-8 to the new Henness Road. Besides minor saw cutting, the The interchange is being designed as part of the Henness Road extension, existing I-8 roadway will remain with no other construction improvements. The comparison of the alternatives consisted of analyzing the benefits of the connecting the existing northern portion of Henness Road to the I-8 corridor. roadway construction when compared to the benefits of no construction. 4.5.1 No-Build Alternative (Not Recommended) The location of the interchange along I-8 is somewhat limited based on the 4.7 Conclusion existing Henness Road alignment. Additionally, the proximity of the project The No-Build Alternative is provided for comparison purposes. Under this location to the I-8/I-10 interchange restricts any re-alignment of Henness Road alternative, the I-8 corridor would remain in its present condition. Only regular to the east. Although construction will involve impacts to existing environmental, maintenance activities would be conducted. This alternative provides no earthwork, and drainage conditions, in addition to potential short-term delays improvements to the safety, capacity, or operational characteristics of the Existing terrain features also restrict the intersection’s design. The terrain during construction, the positives for construction outweigh the negatives. existing roadway and involves no cost or change to the corridor’s immediately south of the I-8 corridor is mountainous, which forces the Construction of the new corridor will improve access to the I-8 corridor from environmental features. intersection between Henness Road and the future Lamb Road extension to be the City of Casa Grande, lessen traffic volumes along I-8 eastbound, and promote future economic growth. Furthermore, ADOT will incur no costs for close to the TI. Additionally, a canal runs north of the project, which limits the The No-Build Alternative does not address the existing connectivity issues construction and R/W acquisition. Therefore, the Build Alternative is the available locations for northern intersections with Henness Road. between I-8 and the City of Casa Grande road network, does not support future recommended alternative to be carried forward for further development. economic development, and does not help alleviate traffic volumes at the I-8/I-
14 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Table 4.1 – Alternative Evaluation Matrix
“BUILD” ALTERNATIVE EVALUATION CRITERIA “NO BUILD” ALTERNATIVE Henness Road Traffic Interchange
Right-of-Way Needs None. R/W for TI will be donated to ADOT by property owner in exchange for future construction of C-D Roads.
Result: Neutral Result: Advantage Land Use Impacts With an absence of access to the northwest quadrant of the I-8/I-10 interchange, any development With access, the land will be open for development spurring economic activity. potential is limited.
Result: Disadvantage Result: Strong Advantage Environmental Impacts No environmental impacts No significant environmental impacts are anticipated Wildlife/Habitat Impacts Threatened / Endangered / Sensitive Species Affected Result: Advantage Result: Slight Disadvantage Earthwork None. 400,154 cubic yards of borrow will be required to build the TI.
Result: Neutral Result: Strong Disadvantage Use of Existing Road There is no existing road at the Henness Road alignment. Henness Road will be built at the proposed alignment and will be connected to the City of Casa Grande arterial street system.
Result: Neutral Result: Advantage Roadway Geometry None. The proposed geometry is in conformance with the current standards.
Result: Neutral Result: Neutral Constructability None. No constructability issues are anticipated. The new TI construction will have minimal traffic control & Traffic Control impacts to I-8 that will be limited to single-lane closures.
Result: Advantage Result: Disadvantage Estimated Construction Cost (approximate) $0 $ 19,956,000 (Henness Road TI will be privately funded.) Funding Result: Neutral Result: Strong Advantage Access No changes to I-8 access, which limits access between Trekell Road TI and Selma Highway TI. Henness TI will provide a new access point on I-8 between Trekell Road TI and Selma Highway TI.
Result: Strong Disadvantage Result: Strong Advantage Drainage/Floodplains No impacts or improvements. Impacts to floodplains will be minimal. Existing drainage pattern will be maintained.
Result: Advantage Result: Disadvantage Utility Impacts No impacts. Minimal impacts to utilities are expected.
Result: Neutral Result: Disadvantage Structures No impacts or improvements. A new bridge will be available over I-8.
Result: Neutral Result: Advantage Connectivity and Continuity No connectivity with the City of Casa Grande road network Provides future connectivity to the City of Casa Grande road network.
Result: Strong Disadvantage Result: Strong Advantage
15 I-8/Henness Road TI, MP 176 –Final Design Concept Report
5.0 Major Design Features of the Recommended ultimately become left-turn lanes, and one right-turn lane providing access to horizontal alignment travels perpendicular across the existing I-8 and consists Ramp A. The northbound and southbound lanes are separated by a 15-foot of one horizontal curve that aligns the roadway with the future improvements. Alternative raised concrete median. Due to the additional right turn lane, the face of curb This road is designed to ADOT and AASHTO standards for a 45 mph design to face of curb width of the roadway is 136 feet. The right turn lane and the speed. 5.1 Introduction bike lane width is a total of 19 feet. The bike lane is provided between the The horizontal alignments of the ramps are designed to be taper type. Ramp A This section provides a description of the major design features of the southbound right turn lane and the outermost southbound through lane. After begins with a horizontal curve and connects via a tangent section to Henness recommended alternative. 300 feet, the total roadway width tapers over a distance of 180 feet from 136 feet back to 124 feet, eliminating the 12-foot southbound right-turn lane. Road. Ramp B begins with a flatter curve, which is required to tie-in to the The project length extends from the beginning of Ramp A at westbound I-8 curve of the I-8 eastbound, followed by a short tangent section and another station 3121+50 (MP 176.03) to the end of Ramp C at eastbound I-8 station After this taper, three northbound lanes and five southbound lanes are horizontal curve, which then connects to Henness Road via a tangent section. 3330+00 (MP 177.28). A station equation exists on eastbound I-8 between provided, separated by a 15-foot raised concrete median. This continues for Ramps C and D begin tangentially from Henness Road and consist of two stations 3148+38 and 3291+15. A station equation exists on westbound I-8 250 feet, after which time the two inside southbound travel lanes taper down reverse horizontal curves separated by a tangent section. The ramps are between stations 3149+72 and 3291+15. The total project length along I-8 is over a distance of 180 feet. During this taper, the concrete median widens from designed for 65 mph through the ramp gore section, 50 mph through the ramp 6,575 feet or approximately 1.2 miles. 15 feet to 38 feet. body, and 35 mph at the ramp terminus.
5.2 Typical Sections and Median Widths The final segment of Henness Road consists of three northbound and three The vertical alignment for Henness Road begins on its southern end following southbound 12-foot travel lanes separated by a 38-foot raised concrete median. the normal crown of the future Lamb Road. After this, the vertical alignment Throughout all portions of Henness Road, curb and gutter is provided along 200 feet before the end of Henness Road construction, the travel lanes are consists of a grade break of 0.20%, which is less than the maximum allowed the outer edges of pavement. The face of curb to face of curb width of the separated by a 42-foot at-grade median. break of 0.40%. The vertical profile consists of two sag vertical curves, one roadway is 124 feet in all sections. A 5-foot bike lane, measured from the face before and after the bridge, and one crest curve, the peak of which is located of curb to the outermost travel lane, is provided in all sections. When a raised Ramp A is a taper type ramp beginning at westbound I-8 with one 12-foot on the bridge and is designed to provide adequate clearance over I-8. The concrete median is used to separate travel lanes, a 2-foot buffer on both sides is travel lane, an 8-foot left shoulder, and a 2-foot right shoulder. Ramp A will terminus of the Henness Road vertical profile is significantly lower in provided between the median and the nearest travel lane. A 6-foot sidewalk is taper to include a second 12-foot travel lane with a 2-foot left shoulder. elevation than its beginning in order to match existing grades. Adequate provided detached 5 feet from the back of curb, except on the bridge, where stopping sight distance is provided throughout for a 45-mph roadway Ramp B is a taper type ramp beginning at eastbound I-8 with one 12-foot lane, the sidewalk would be attached to the curb. An 8-foot graded area is provided according to ADOT and AASHTO standards. an 8-foot right shoulder, and a 2-foot left shoulder. Ramp B will taper to behind the sidewalk from which 6:1 slopes tie into existing ground. include a total of three 12-foot travel lanes, a 2-foot left shoulder, and a 2-foot The vertical profiles of the ramps are controlled through the gore areas by the Beginning from the southern end of the project, Henness Road consists of four right shoulder. existing I-8 profile. Once beyond the gores, the ramps consist of three vertical northbound 12-foot lanes, four through lanes out of which one becomes a left curves and a continuous rise to tie into Henness Road at their terminus. Ramp C is a taper type ramp beginning at Henness Road with three 12-foot turn lane providing access to Ramp A and three southbound 12-foot lanes, Adequate stopping sight distance is provided throughout according to ADOT travel lanes, a 2-foot left shoulder, and a 2-foot right shoulder. Ramp C will which provide adequate width for turn lanes onto future improvements. The and AASHTO standards. taper to include two 12-foot travel lane, a 2-foot left shoulder, and a 2-foot northbound and southbound lanes are separated by a 30-foot at-grade median right shoulder. At the back of gore the ramp tapers down to one 12-foot travel for 180 feet, after which they are separated by a 27-foot raised concrete The Stage I plan sheets are included in Appendix B. lane, a 2-foot left shoulder and an 8-foot right shoulder. median until the intersection with Ramps B and C. An additional dedicated 5.4 Access right turn lane providing access to Ramp C is also provided. Ramp D is a taper ramp beginning at Henness Road with four 12-foot travel lanes, a 2-foot left shoulder, and a 2-foot right shoulder. Ramp D will taper to Additional access from I-8 to the surrounding roadway system will be After this intersection, the bridge over I-8 provides four northbound 12-foot one 12-foot travel lane, an 8-foot left shoulder, and a 2-foot right shoulder. provided by the proposed TI. The Henness Road extension will provide direct travel lanes including three through lanes and one left-turn lane providing access to the City of Casa Grande from I-8. Access to Peart Road to the access to Ramp A, and five southbound 12-foot lanes including three through The typical sections are included in the Stage I (15%) plans in Appendix B. northwest will be provided through a connecting roadway at the mid-section lanes and two left-turn lanes providing access to Ramp C. These lanes are line between Selma Highway and Cornman Road. separated by a 4-foot raised concrete median. 5.3 Horizontal and Vertical Alignments The City of Casa Grande has included this Henness-Peart connector roadway After the bridge, the roadway consists of three northbound 12-foot through The Henness Road horizontal alignment is designed to connect future in its five-year Capital Improvement Plan (CIP) for the year 2018 (Project # lanes and six southbound 12-foot lanes, five through lanes of which two improvements along Lamb Road to the future extension of Henness Road. The
16 I-8/Henness Road TI, MP 176 –Final Design Concept Report
18-STR-2575). Pinal County has also included this roadway in its five-year New R/W needed along Ramp B varies from the existing R/W of 80 feet offset 50-Year Flow (cfs) CIP for budget years 2016-17. The excerpts from these CIPs are included in from the Ramp B centerline to a maximum of 120 feet offset from the Ramp B Culvert Description of Existing Culvert Appendix J. centerline. ID At Inlet 1 Culvert 2 Bypass 3
Future plans involve the extension of Lamb Road along the I-8 corridor on the New R/W needed along Ramp C varies from a maximum of 217 feet to a 5b 24” RCP 2 2 0 south side. Once the Lamb Road extension is completed, the connection to minimum of 115 feet offset from the Ramp C centerline. Henness Road on the south end will provide access to parcels south of the I-8 6 60” RCP 37 29 8 corridor. Additionally, connection with the Lamb Road extension will provide New R/W needed along Ramp D varies from a maximum of 228 feet to a access to the Peart Road. minimum of 105 feet offset from the Ramp D centerline. 7 36” x 22” CMP 7 7 0
5.4.1 Access Control 5.6 Drainage 8 2 – 8’ x 4’ CBC 302 302 0 1. Flow that reaches the upstream end of the culvert. According to the ADOT Access Control Model for Crossroads on Controlled 5.6.1 Existing Culverts and Bridges 2. Flow that is conveyed through the culvert. Access Highways, dated 2006, access to TI crossroads is restricted for a set 3. Flow that bypasses the culvert or overtops the road. distance from the end of the ramp radius to the nearest crossroad. A summary of the existing culverts is provided below in Table 5.1. Seven culverts cross I-8 in the project area, and one culvert crosses Tate Road south 5.6.2 Drainage Requirements and Recommended In the case of a minor road intersecting the TI crossroad on one side only, of I-8. An existing channel parallel to I-8 conveys off-site flow to a system of Improvements access is restricted within 1,320 feet of the ramp tapers. An example of this culverts crossing I-8 east of the proposed TI. occurs at the intersection north of the TI between the future Henness Road and Proposed drainage improvements consist of extending existing culverts Cornman Road. This intersection will be approximately 1,300 feet from the Several split flows occur in the study area. The majority of the split flows crossing I-8 and constructing drainage ditches to convey runoff along the ramp radius along the future Henness Road alignment, and therefore will fall occur because the natural channels conveying runoff to the culverts are not proposed interchange ramps to the culverts. Five culverts will need to be within this access restriction. The location of this intersection is restricted due well defined. As summarized in Table 5.1, flows exceeding the capacity of extended upstream and seven culverts will need to be extended downstream. to the already existing alignment for Cornman Road. In addition right-in/right- the natural channels bypass the culvert and continue to the next downstream A summary of the proposed flows at these culverts is provided in Table 5.2. out access is allowed 750 feet from the ramp radius. Thus ADOT access culvert. control will be limited at 750 feet from the ramp radius. Table 5.2 – Summary of Proposed Flows at Culverts Table 5.1 – Summary of Existing Culverts
In the case of a four-way intersection, the minimum distance from the end of Culvert 50-Year Flow (cfs) 50-Year Flow (cfs) Description of Proposed the ramp radius and the centerline of the intersecting roadway is 2,640 feet. An Culvert Description of Existing Extensions ID At Inlet 1 Culvert 2 Bypass 3 example of this occurs immediately south of the project at the intersection of ID Culvert 1 2 3 future Henness Road and the future Lamb Road extension. This distance will At Inlet Culvert Bypass 1 EB U/S: 2 – 10’ x 5’ CBC 298 298 0 be approximately 600 feet and will therefore fall within this restricted distance. 1 EB 2 – 10’ x 3’ CBC 277 277 0 This scenario is unavoidable as the location of the future intersection is 1 WB D/S: 2 – 8’ x 4’ CBC 302 302 0 restricted due to existing topography and natural features. Due to the 1 WB 2 – 10’ x 3’ CBC 280 280 0 mountainous terrain directly south of the I-8 corridor, the location of this 2 EB U/S: 24” RCP 83 53 30 intersection is restricted to this area. 2 EB 50” x 31” CMPA 84 44 40 2 WB D/S: 36” RCP 55 55 0 5.5 Right-of-Way 2 WB 50” x 31” CMPA 45 45 0 3 EB U/S: 2 – 36” CMP 74 57 17 Approximately 31 acres of new R/W will be required as part of this project for 3 EB 2 – 36” CMP 84 65 18 the Henness Road TI. The R/W ownership will be transferred to ADOT 3 WB D/S: 2 – 36” RCP 65 65 0 3 WB 2 – 36” RCP 68 68 0 through a JPA prior to the construction of the TI. U/S: 36” RCP 4 36” RCP 4 172 165 7 New R/W needed along Ramp A varies from the existing R/W of 61 feet 173 107 66 D/S: 36” RCP offset from the Ramp A centerline to a maximum of 115 feet offset from the 5a 40” x 27” CMPA Ramp A centerline.
17 I-8/Henness Road TI, MP 176 –Final Design Concept Report
in the area. A team of environmental scientists then verified the location and 50-Year Flow (cfs) Cut (CY) Fill (CY) Net (CY) Culvert Description of Proposed nature of the watercourses in the field. Extensions ID At Inlet 1 Culvert 2 Bypass 3 Total: 31,257 431,410 -400,153 A number of small ephemeral washes were noted within the project area, but 5a D/S: 24” RCP they do not outfall to the Casa Grande Canal. This lack of connectivity precludes these washes from being considered waters of the U.S. This area 5.9 Geotechnical 5b D/S: 24” RCP 2 2 0 also does not appear to qualify as an impoundment of waters of the U.S.; therefore, it was recommended that no jurisdictional waters of the U.S. are A geotechnical investigation will be completed during final design. 6 No extension 37 29 8 present within the project area. 5.10 Constructability and Traffic Control 7 No extension 7 7 0 The USACE makes the final determination regarding jurisdictional waters of No traffic control or constructability issues are anticipated. U/S: 2 – 8’ x 4’ CBC the U.S. If the USACE concurs with the findings, a permit will not be required to construct the proposed project. If, however, the USACE disagrees with the 8 281 281 0 Access for construction will be evaluated during final design. Access points D/S: 2 – 8’ x 4’ CBC findings and determines that jurisdictional waters of the U.S. are present, a and dirt roads exist both north and south of the TI to facilitate construction permit will be required to construct the proposed project or for any other future 1. Flow that reaches the upstream end of the culvert. without requiring construction accesses from I-8. 2. Flow that is conveyed through the culvert. impacts to waters of the U.S. 3. Flow that bypasses the culvert or overtops the road I-8 mainline shoulder closures will be required for ramps construction. 5.8 Earthwork 5.11 Intersections Appropriate scour protection will be provided downstream of each culvert. Earthwork values were calculated using the End Area method. Shrink and Drainage ditches will be required to convey runoff along the proposed swell factors were both assumed to be 1.0. A geotechnical report will need to Two intersections will be constructed as part of this project. The south interchange ramps to the culverts. be obtained during final design in order to determine the correct shrink and intersection is between Henness Road, Ramp B and Ramp C. Approaching swell factors. Area inlets will need to be provided between the proposed interchange ramps Henness Road, Ramp B consists of two left-turn lanes and one right-turn lane. Departing Henness Road, Ramp C consists of three through lanes. South of the and the existing roadway to convey runoff to existing cross culverts. Using these assumptions, the project will have a cut volume of 31,257 cubic intersection, the northbound Henness Road section consists of four through yards and a fill volume of 431,410 cubic yards for a total project borrow of lanes and one right-turn lane. The southbound Henness Road section consists As part of the future Lamb Road extension and Henness Road construction, 400,154 cubic yards. nine additional culverts will be required. Seven culverts will be needed to of three travel lanes. North of the intersection, the southbound Henness Road convey runoff underneath the future Lamb Road extension. Two culverts are The earthwork values for each portion of the project are detailed below in section consists of three through lanes and two left-turn lanes. proposed to convey runoff across Henness Road north of I-8. Table 5.3. The north intersection is between Henness Road, Ramp A and Ramp D. The drainage calculations are included in the Drainage Report in Appendix F. Table 5.3 – Earthwork Summary Approaching Henness Road, Ramp D consists of two left-turn lanes and one right-turn lane. Departing Henness Road, Ramp A consists of two through 5.7 Section 404 of the Clean Water Act Cut (CY) Fill (CY) Net (CY) lanes. South of the intersection, the northbound Henness Road section consists of one left-turn lane and three through lanes. The southbound Henness Road The U.S. Army Corps of Engineers (USACE) administers Section 404 of the Henness Road 21 286,854 -286,834 section consists of five through lanes. North of the intersection, the northbound Clean Water Act and issues permits to control and monitor the discharge of section of Henness Road consists of three through lanes. The southbound earthen fill into jurisdictional waters of the U.S. A preliminary study was Ramp A 676 54,471 -53,795 section of Henness Road consists of one right-turn lane and five through lanes. undertaken in the fall of 2009 to determine if any possible jurisdictional waters Ramp B 3,941 26,994 -23,053 of the U.S. exist within the vicinity of the proposed I-8/Henness Road TI The total number of lanes at each intersection is summarized in Table 5.4. project. Ramp C 13,129 21,699 -8,569
The ‘Jurisdictional Delineation’ effort included a review of aerial photographs Ramp D 12,623 41,392 -28,769 and topographical maps to identify possible jurisdictional washes/watercourses Ditch Excavation 867 867
18 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Table 5.4 – Lane Geometry Proposed at Intersections Telecommunications 5.15 Pavement Design
Number of Number of Number of No telecommunication lines are present; hence, there is no conflict with the The pavement structural section utilized for cost estimating purposes was 12 Through Number of Departure Approach recommended alternative. inches of Asphaltic Concrete over a 10-inch Asphalt Base Course. Lanes on Turn Lanes Lanes on Lanes on Intersection Henness on Henness Ramp Ramp Table 5.5 lists the utilities on the project and their contact information. This structural section is based on the structural section used in previous projects in the area. A geotechnical report will need to be developed during Henness/Ramps A 8 2 2 4 & D Table 5.5 – Utility Contacts final design, and the pavement design will be updated at that point. Henness/Ramps B 7 3 2 3 NAME COMPANY STATUS PHONE 5.16 Design Exceptions/Variances & C Ronal Passannanti ADOT Electrical No Conflict (520) 838-2848 Superelevation design variance are required for Ramps A and B at the Michael Voda, P.E SRP No Conflict (602) 809-1372 mainline tie-ins due to inadequate superelevation of the existing I-8 mainline 5.12 Utilities Frank Garcia APS No Facilities (520) 421-8365 roadway. Hard survey shots will be performed during final design to confirm the mainline roadway cross slopes. A design variance was approved by the AZ Water No major utility conflicts are anticipated during construction of the Henness Chris Tapia No Facilities (520) 836-8785 ADOT Roadway Engineering Group and is included in Appendix K. Road TI. Minor utility relocation may be required during construction. Company Chris Lertique CenturyLink No Facilities (602) 630-0492 5.17 Joint Project Agreements Irrigation and Drainage San Carlos Benjamin Errair Irrigation Project - Potential Conflict (520) 723-6208 A Joint Project Agreement will be developed between the CGMR and ADOT. Arizona Water Company owns waterlines along Lamb Road and Peart Road Power CGMR has agreed to deed the appropriate land for both the I-8 / I-10 system alignment. No waterlines are within project limits. San Carlos interchange (northwest corner) and the C-D roads (between I-10 and Henness Clarence Begay Irrigation Project - No Conflict (520) 723-6203 Road TI) subject to ADOT/FWHA's final approval of the Henness Road TI Power/Electric Irrigation DCR, COAR and construction approval for the Henness Road TI. In return, ADOT has agreed to construct the C-D roads along with the I-8 / I-10 system ADOT lighting facilities and electrical lines at the of I-8 / I-10 system Darren Rutledge Southwest Gas No Facilities (520) 316-5021 interchange when they become necessary. interchange should not be impacted. 5.13 Railroads A JPA will be developed between the ADOT and the City of Casa Grande for San Carlos Irrigation Project overhead power lines (12.47kV) exist along I-8 the City to take the ownership and maintenance of Henness Road after and may need to be relocated as the lines cross Henness Road close to I-8 A Union Pacific Railroad line is located approximately 0.4 miles north of the construction. south of the ramp intersection. The Henness Road vertical profile is raised due project location. No conflicts are anticipated as a part of this project. to the crossing over I-8. This will decrease the vertical clearance of the lines 5.18 Implementation significantly. Prior Rights will be determined at the beginning of final design 5.14 Structures and a relocation design will be developed. Pertinent information for the new bridge structures proposed for this project Construction of the Henness Road TI will be privately funded. R/W for the TI are summarized in Table 5.6. More detailed information is included in the will be donated to ADOT. ADOT will be responsible for the maintenance of Salt River Project (SRP) has a 130-foot wide easement parallel to I-8 and just the TI after construction. south of the Cornman Road alignment crossing the proposed Henness Road. Bridge Selection Report in Appendix G. SRP constructed 500kV overhead power line within this easement. One of the The City of Casa Grande will be responsible for owning and maintaining Table 5.6 – Proposed Bridge Summary power poles is 115 feet from the Henness Road centerline and is not Henness Road after its construction outside of the ADOT controlled access anticipated to be in conflict with the project improvements. limits. The access control will be implemented and preserved by COCG. An Begin End Bridge Location Station Station No. of Spans Length Type IGA between COCG and ADOT will be prepared addressing the COCG Natural Gas responsibilities for maintaining access control beyond ADOT R/W. Precast Henness Road 18+62.00 21+38.00 2 276 No gas lines are present; hence, there is no conflict with the recommended Concrete As described earlier in this report, Henness Road TI will be constructed as a alternative. compact diamond TI in the interim phase. Henness Road will be connected
19 I-8/Henness Road TI, MP 176 –Final Design Concept Report
with the City of Casa Grande street network by extending Henness Road north to the Cornman Road section line and then west to connect with the existing Peart Road.
ADOT will reconstruct the I-8 / I-10 system interchange as a part of the ultimate long-range improvements in these corridors. The Henness TI ramps east of the TI will be removed and replaced with C-D roads during this ultimate phase.
5.19 Future Street Network
The following street extensions are anticipated to be constructed in the future in the vicinity of the proposed Henness Road TI:
As shown in Figure 6-1 Year 2030 Roadway Improvement Plan of the 2007 City of Casa Grande SATS, Henness Road is anticipated to continue north across the Casa Grande Canal by 2030 to provide regional access to Casa Grande via the Henness Road interchange. To the south, Henness Road will terminate at the intersection with the proposed Lamb Road extension. A copy of Figure 6-1 from the SATS is included in Appendix I.
Cornman Road is proposed to extend east and west of Henness Road on the existing Cornman Road alignment to provide access to future surrounding development. The existing Lamb Road is proposed to extend east from Trekell Road, provide access to Henness Road, and terminate at the existing Cox Road alignment.
20 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Figure 5.1 – Henness Road Traffic Interchange Design
21 I-8/Henness Road TI, MP 176 –Final Design Concept Report
Figure 5.2 – Henness Road Traffic Interchange with Future Connections
22 I-8/Henness Road TI, MP 176 –Final Design Concept Report
6.0 Social, Economic, and Environmental constituents within the project area are Pinamt-Momoli complex, 1 to 8 located within Pinal County must adhere to the Arizona Department of percent slopes; Denure fine sandy loam, 0 to 1 percent slopes, Casa Grande Environmental Quality (ADEQ) air quality rules and regulations. Concerns clay loam, and Vaiva-Rock outcrop complex, 15 to 50 percent slopes. Noise A Categorical Exclusion is the anticipated level of NEPA documentation for this project. The environmental aspect of the study area constitutes the basis The federal list of threatened and endangered (T&E) species for Pinal County was obtained from United States Fish and Wildlife Service (USFWS) through The FHWA regulations for mitigation of roadway traffic noise in the planning for the evaluation of the proposed actions and how they will collectively and design of federally aided roadways are contained in Title 23 of the United impact the human environment. To satisfy the objectives of this study, several the Arizona Ecological Services Field Office website (www.fws.gov). Within Pinal County, there are two T&E species and three candidate species. States Code of Federal Regulations (CFR) Part 772. ADOT has adopted a reports have been developed under separate covers to present details of State Policy, the Noise Abatement Policy for Federal Aid Projects as amended findings regarding impacts on socio-economic, physical, natural, and cultural Information obtained from the AGFD On-line Environmental Review Tool in 2007, which is consistent with the FHWA Highway Traffic Noise Analysis aspects of the environment, as well as to present the details of planning and reported that the western burrowing owl (Athene cunicularia hypugaea), and Abatement Policy and Guidance. The majority of the study area is analysis for public disclosure. Individual environmental documents that have Sonoran desert tortoise (Gopherus agassizii) and western yellow bat (Lasiurus composed of undeveloped land. been or are currently being prepared for this project include: xanthinus) have been documented as occurring within three miles of the Hazardous Materials § Biological Review (BR); project area. § Preliminary Initial Site Assessment (PISA); 404 Resources A Preliminary Initial Site Assessment (PISA) was performed in 2009 for the § Class I Literature Review (Cultural Resources); project area. At that time, no identified hazardous material sites were located § Class III Survey and Report (Cultural Resources); A preliminary Jurisdictional Determination (JD) was issued by the USACE on within or immediately adjacent to the project. PISA documents have a shelf § SHPO/Tribal Consultation Documents (Cultural Resources); October 13, 2010. Based on the information provided to the USACE, it has life of 180 days according to ADOT guidance. The PISA will need to be updated as part of the environmental clearance process. § Preliminary Jurisdictional Delineation (PJD); been determined that the project is within identifiable waters of the United States. The permit applicant is advised of the option to request and obtain an § Clean Water Act Section 404 Permit; and approved JD; however, the option to obtain an approved JD in this instance 6.2 Cultural Resources/Section 4(f) Properties § Categorical Exclusion Checklist (CE). and at this time was declined. For purposes of computation of impacts, compensatory mitigation requirements, and other resource protection In 2009, 201 acres were surveyed by Aztlan Archaeology Inc. in support of the 6.1 Summary of Physical and Natural Environment measures, a permit decision made on the basis of a preliminary JD will treat all environmental studies for the project. Class I and Class III reports were prepared that identified one previously recorded archaeological site that was Biology waters and wetlands that would be affected in any way by the permitted activity on the site as if they are jurisdictional waters of the United States. determined as eligible for the National Register of Historic Places (NRHP) under Criterions A (Properties associated with events that have made a The project area is categorized as Sonoran Desertscrub, Mixed Scrub Series Floodplains significant contribution to the broad patterns of our history) and D (Properties (Brown et al 1994). Native plant species that occur within the project limits that have yielded or are likely to yield important information about the past) by include mesquite tree (Prosopis glandulosa), foothill paloverde (Cercidium The project area is not located within any 100-year floodplains according to the State Historic Preservation Office (SHPO). Further review and evaluation microphyllum), cat claw acacia (Acacia greggii), cane cholla (Opuntia FEMA Flood Insurance Rate Maps (FIRM) map number 04021C1555E of this site may also identify it as a 4(f) resource. spinosior), strawberry hedgehog cacti (Echinocereus stramineus), brittlebush effective 2007. (Encelia Farinosa), creosote (Larrea tridentata), saguaro (Carnegiea In addition to the one eligible site, two other archaeological sites were gigantica), triangle leaf bur-sage (Ambrosia deltoidea), teddy bear cholla Air Quality identified during the field survey of the project area. These two additional (Opuntia bigelovii) and desert broom brush (Baccharis sarothroides). The archaeological sites do not meet the criteria for eligibility to the NRHP. elevation is approximately 1,460 feet above mean sea level (MSL). The The project area is within the Pinal County air quality non-attainment area for project area gently slopes and drains to the north/northwest. The project area PM10, which has transportation control measures in the State Transportation Further Section 4(f) coordination with the appropriate agencies and is located in mostly undisturbed native desert area. The project area is bound Improvement Plan (STIP) and Federal Implementation Plan. Projects within departments would be required if project activities impact any identified by undeveloped land, agricultural land and a portion of the Casa Grande the study area will need to be included in an approved transportation Section 4(f) Resource aforementioned properties or the entrances to the related Canal to the north, undeveloped land to the east, and undeveloped land and a improvement plan for at least one year, and no more than three years, prior to sites. portion of the Casa Grande Mountain to the south and west. According to the construction. The Transportation Improvement Plan will have to be approved United States Department of Agriculture Natural Resource Conservation by the FHWA and Environmental Protection Agency (EPA) as conforming to Compliance with cultural resource laws will be an important component of the Service’s (USDA-NRCS) website the STIP and the Federal Implementation Plan. Any construction activity project. Cultural resource compliance with existing legislation requires (http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx), the main soil
23 I-8/Henness Road TI, MP 176 –Final Design Concept Report
adequate time to account for agency reviews and possible testing and/or data recovery, which must be factored into the planning process.
6.3 Conclusions
An individual Categorical Exclusion (CE) is the anticipated level of NEPA documentation for this project.
24 I-8/Henness Road TI, MP 176 –Final Design Concept Report
7.0 Opinion of Probable Cost Estimate Cost estimates have been prepared for the recommended Build Alternative. The No-Build Alternative does not have any capital cost. The detailed cost estimates for the Build Alternative are included in Appendix C. Unit prices are based on recent ADOT bid results for work in the general area.
The cost summary for the recommended Build Alternative is:
Construction: $ 15,479,500 Construction Admin & Contingencies: $ 3,065,500 Utility Relocation: $ 50, 000 Right-of-Way: $ 471,000 Design: $ 890,000 Total: $ 19,956,000
7.1 Construction Costs and Assumptions
For the purposes of cost estimating, the pavement structural section for Henness Road and the ramps was assumed to be four 3-inch lifts of AC (Asphaltic Concrete) over 10 inches of AB (Class 2) with ½ inch of Asphaltic Concrete Friction Course (ACFC). A sawcut width of 2 feet measured from the existing edge of pavement of westbound I-8 was assumed at the entrance and exit ramp termini.
25 I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX A: Change of Access Report (under separate cover) I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX B: Typical Sections and Plan Sheets (Recommended Alternative) I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX C: Cost Estimate (Recommended Alternative) I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX D: Soil Survey I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX E: Traffic Report and Addendum (under separate cover) I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX F: Drainage Report (under separate cover) I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX G: Bridge Selection Report (under separate cover) I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX H: I-8 / I-10 System Interchange Preferred Alternative I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX I: Figure 6-1 2007 City of Casa Grande SATS I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX J: Henness-Peart Road Connector - City of Casa Grande and Pinal County CIP I-8/Henness Road TI, MP 176 –Final Design Concept Report
APPENDIX K: Design Variance Approval