FDOT Experience with PBES for Small-Medium Span Bridges Steven Nolan, P.E, Dept. of Transportation (1), (850) 414-4272, [email protected] Sam Fallaha, P.E, Florida Dept. of Transportation (1), (850) 414-4296, [email protected] Vickie Young, P.E, Florida Dept. of Transportation (1), (850) 414-4301, [email protected] (1) State Structures Design Office, 605 Suwannee St, Tallahassee FL. 32399

ABSTRACT In the last quarter century, some elaborate methods of accelerated bridge construction (ABC) have been explored and executed in Florida, predominately though necessity in the segmental construction. ABC techniques have also been applied to more traditional flat-slab and slab-on-girder bridges including: Prefabricated Bridge Elements and Systems (PBES), full size bridge moves, top down construction, and other efforts to minimize road user delays and environmental impacts. This paper focuses on four modest structural systems which were successfully implemented on FDOT construction projects since the initiation of FHWA’s Every Day Counts program. This discussion focuses on ABC structural systems for: Precast Intermediate Bent Caps, Precast Full-Depth Bridge Deck Panels, Prestressed Concrete Florida-Slab Beams, and Geosynthetic Reinforced Soil Integrated Bridge Systems.

INTRODUCTION Florida has been heavily involved in accelerated bridge construction activities (ABC) since the middle of the last century, primarily driven for economic advantage, with efforts predominantly led by the precast concrete industry. In the last quarter century, some elaborate methods of accelerated bridge construction have been explored and executed in Florida, predominately though necessity in the post-tensioned (PT) segmental construction to provide economy through speed of fabrication and erection, to offset significant mobilization and setup cost, specialized PT subcontractors and equipment. ABC techniques have also been applied to more traditional flat-slab and slab-on-girder bridges including: Prefabricated Bridge Elements and Systems (PBES), full size bridge moves, top down construction, and other efforts to minimize road user delays and environmental impacts. There have been some lessons learned on the quest for more rapid and economical construction, however the predominance of successful projects should encourage further ABC innovation and application. This paper focuses on four practical structural systems which where demonstrated on several FDOT construction projects since the initiation of FHWA’s Every Day Counts program. These ABC structural systems include: 1. Precast Pile Bent Caps; 2. Precast Full-Depth Bridge Deck Panels; 3. Prestressed Concrete Florida-Slab Beams; 4. Geosynthetic Reinforced Soil Integrated Bridge Systems. These systems represent a narrow but potentially prolific scope of the ABC initiative and reflect some of the structural priorities of the FDOT, and lessons learned during the period of 2010 to 2018.

BEFORE “EDC” Long before the FHWA’s “Every Day Counts” programs formalized the term Prefabricated Bridge Elements and Systems (PBES) under the ABC initiative in 2011 & 2013, this concept had been used since the 1950’s in Florida at various scales and complexity, especially with precast/prestressed components. One of the first and largest prestressed beam bridge project began in 1951, shortly after the successful Walnut demonstration in Pennsylvania (1). The first Sunshine Skyway crossing involved production, delivery and erection of 2,178 prestressed beams of 48-feet for the 3 miles of the approach trestle spans (2) at the mouth of . A similar parallel bridge was completed in 1971 to bring it to Interstate standards as a dual carriageway. This feat was later rapidly repeated with the upgraded replacement crossing in 1986 after the tragic MV Summit Venture bridge collision (3). 1,300 longer AASHTO Type IV prestressed beams were used for the trestle approaches (and the longest segmental box cable-stay bridge in the US at the time (4). Prior to the new Skyway, replacement of the (35,867 ft. long) in the Florida Keys saw the construction of the longest precast concrete bridge in the world completed at the time (1982), with a maximum of five spans erected in one week (5). Sixteen years later the 18,425-ft. achieved a world record “seven [140 ft.] spans erected in seven consecutive days” (6) in May 1998, with the 19,265-ft. Mid-Bay Bridge completed five years earlier in just 25 months (7), all using span-by-span segmental construction as a proof points for ABC.

There were some connection integrity issues that arose from the early effort in the “need for speed” in construction. Match-cast dry-joint segmental box connections did not provide the desired water tightness needed for low-maintenance highly durable structures (, 1978) (8). Requirements for pre- package post-tensioning grout, to improve the flowability and subsequent quality of duct filling, did not provide the desired elimination of voids or complete protection of the steel-strands as hoped (Sunshine Skyway and Wonderwood Bridges) (9) (10). Accelerated schedules for design, review, and construction activities on design-build projects resulted in undesirable effects including: plunging of a complete pier foundation during segmental span erection (Selmon Expressway, 2004), warping of split-box segments (Ringling Causeway, 2002), segment box joint opening under traffic (Hathaway, 2012), and the collapse of a partially completed bridge over traffic discussed by Zhou et al. (2019) (11) and Cao et al. 2019 (12).

PRECAST PILE BENT CAPS Precast pile bent caps were used on several Florida bridge projects since the 1990’s ( 1993), sometimes at the initiative of the contractor (, 1997), inspiring initiatives for standardization in the late 1990’s by LoBruono, et al. (1996) (13) that were never fully realized. Design-Build project such as St. George Island bridge replacement (2004); and I-10 over Escambia Bay (2007), both utilized precast bent caps but with different precast piling systems. After the rollout of the Every Day Counts initiative and completion of the NCHRP Report 681 (14), there was renewed interest in standardizing due to improved design provisions for the connections of PBES. The FDOT 2013-2014 demonstration project on US90 over Little River (15) provided positive performance of the grouted duct connection details on multi-column bents and further developments for standardization of these elements. Subsequent research project BDV30 977- 16 investigated grouted pile pocket connections Kampmann et al. (2017) (16). The results provided recommendations and additional confidence in the constructability of this type of connection for typical driven-concrete pile construction tolerances and hot weather grouting. In 2015, FDOT developed a Mathcad worksheet design tool (17) for precast pile-bent cap analysis. In 2018 the program was updated to include a glass fiber-reinforced polymer (FRP) reinforcing option and published to the FDOT website. Efforts to integrate the output with a future FDOT Standard Plan parametric configuration as discussed in Nolan et al. (2015) (18) are still under consideration. Also, the discussed Standard Plan development in (18) has been delayed in favor of contractor initiated and design-build options, such as the recently completed 2.3- mile SR-90/ bridge in the Everglades National Park shown in Figure 1.

Figure 1: SR-90/Tamiami Trail bridge with 90 precast intermediate pile-bent caps completed in May 2019.

As the most recent example, the SR-90/Tamiami Trail bridge included more than 90 precast pile-bent caps to accelerate the construction schedule for critical path activities of two bridges. The first bridge (7675-ft.) with 56 spans and the second bridge (4650-ft.) with 34 spans. Discussions with the design-build team list several reasons for using precast bent caps including cost and compressing the time for critical path schedule items.

Ongoing FDOT sponsored research related to precast pile connections includes testing and further evaluation of socketed connections in bent caps and footings under research project BDV29 977-51 by Garber (2019) (19). Other FDOT sponsored research is improving the economy of corrosion-resistant precast/prestressed piles using GFRP spiral reinforcing under BDV30 977-27 by Sungmoon et al. (2017) (20), and GFRP pile splicing under BDV29 977-52 by Melarbi and Farhangdoust (2019) (21).

PRECAST FULL-DEPTH DECK PANELS These elements typically are intended for slab-on-girder bridges with either: full-width transverse deck panels with transverse CIP joints; or between-girder spans with longitudinal joints and transverse joints. FDOT has used both systems in recent years, with another novel system implemented at the contractor’s request using a full-length bridge span and longitudinal ultra-high performance concrete (UHPC) joint as shown in Figure 2 (US-441 over Taylor Creek) (22). The same principal has also been applied for two rapid replacements of deteriorated approach slabs on Interstate I-10: Between-Girder Longitudinal Deck Panels Typically, the between-girder span deck slabs have been proposed for rapid replacement of deteriorated decks supported on precast partial-depth stay-in-place forms from 1980-90’s era bridge construction or widening projects, such as I-95 Northbound over CR 5A (Fast-Facts, 2018) (23). This typically allows overnight replacement of damaged deck sections to minimize commuter traffic impacts. Full-Width Transverse Deck Panels Typically, the full-width deck slabs have been used for accelerated construction on new bridges. The FDOT demonstrated this system on US-90 over Little River & Hurricane Creek, which is fully documented under the IBRD instrumentation and monitoring report for BDV30 307-01. Details from this project can be found in the 2014 ABC Conference Proceedings (15) and will not be repeated, how the results from the 4-year load testing and monitoring findings by Roddenberry et al., (2019) (24) confirm the integrity of composite action but also showed the progressive appearance of transverse cracking, which was attributed mostly to shrinkage restraint. Full-length Bridge Slabs with Longitudinal UHPC Joints A recent contractor initiated solution for accelerated bridge replacement utilized large precast slab units that were connected longitudinally with narrow UHPC joints along the crown line (US-441 over Taylor Creek, 2018) (22)

Figure 2: Precast slab bridge with UHPC longitudinal joint for US-441 over Taylor Creek.

Full-length Bridge Approach Slabs with Longitudinal UHPC Joints A slight variation of the full-length bridge slabs is being used for approach slab replacement on two bridges along I-10 in North Florida (Flat Creek and SR-267B) (25) (26). Initially proposed as post-tension precast slabs based on a successful precast concrete pavement project on US92 near Deland, Florida (27). The details were revised mid-way through the design phase to utilize UHPC, simplifying the connection details and potentially accelerating construction.

PRESTRESSED-SLAB BEAMS When devoid of complications from post-tensioning of special connection details, these PBES systems can be a rapidly constructible, cost effective, and offer a robust superstructure solution for modest spans. These beams couple nicely with GRS-IBS systems when geotechnical and hydraulic conditions allow for a complete bridge system, as demonstrated on the SR-373 Bridge over St Marks Trail (28). This project which involved the replacement of a structurally deficient bridge, was completed in six weeks during the summer of 2014. These prestressed-slab beams were the prototype for the standardized Florida-Slab Beams (FSB) (29) that have now been designed into at least 70 bridges with 36 completed as of November 2019. Typical cross-section details are shown in Figure 3.

Figure 3: Typical section for FSB standard bridge configuration available in 12, 15, & 18-inch precast thicknesses

FDOT took this beam system one step further by developing the FSB Superstructure Packages in 2016 (30). These are Developmental Standard Plans that include the full design of a bridge superstructure utilizing the FSBs, to help minimize design time and design costs of a project. These packages (or Standard Plans) include five possible bridge widths that can span three different lengths (30 ft, 40 ft, and 50ft), for a total of fifteen different bridge geometry combinations. Currently there are three ongoing projects utilizing these Developmental Standards.

In addition to the development of the FSB Superstructure Packages, the following efforts to enhance the FDOT prestressed-slab beams include: UHPC longitudinal connections Development of a simplified narrow longitudinal joint utilizing UHPC has the goal of eliminating the 6-inch structural concrete overlay and speeding construction. Limited scale structural testing for optimal joint configuration and fatigue endurance has been completed. Full-scale fatigue and strength testing is expected to be completed in early 2020 under the final phase of this research project by Garber, 2016 (31). Challenges related to rideability due to beam camber, and differential cambers pose constructability issues that may initially limit this application to shorter single span applications. Link-Slabs Link-slabs details for improved longitudinal and lateral resistance from loads associated with truck breaking and storm waves, will allow optimizing foundation design thru load sharing and improved structural resilience from extreme events. Both fiber-reinforced concrete (FRC) and UHPC options are being investigated to minimize the transverse cracking that is often associated with deck continuity systems that are subject to significant rotational demand. Two demonstration bridges are under construction along US41 in Port Charlotte (32) (33). FRP Prestressing and Reinforcing Improved durability for low-level bridge span replacements over salt-water, is being utilized in the Florida Keys. Six spans of US1 over Cow Key Channel are being replaced due to accelerated corrosion degradation from recreational watercraft (34). Carbon FRP prestressing strands in combination with glass FRP shear and supplemental reinforcing, are replacing the traditional carbon-steel elements. A similar configuration for a complete bridge has been designed for the City of St. Petersburg, for the replacement bridge 40th Ave NE over Placido Bayou (35). Stainless-Steel Shear and Supplemental Reinforcing Another form of improved durability for low-level bridge replacements over salt-water, is the use of stainless steel reinforcing for the outer stirrups. Five bridge replacements near Jacksonville Beach are utilizing this strategy for improved durability of PBES components. High-Strength Stainless-Steel (HSSS) prestressing strands in prestressed concrete piles have already been implemented by FDOT under the Standard Plans Index 455-100 series, however HSSS prestressing strands in concrete girders are also under investigation by Roddenberry et al. (2018) (36). The goal is to increase durability performance similar to FRP-PC with the potential for reduced concrete covers and elimination of expensive corrosion inhibitors or highly-reactive pozzolans in the concrete mix.

GEOSYNTHETIC REINFORCED SOIL-INTEGRATE BRIDGE SYSTEM (GRS-IBS) GRS-IBS was standardized by FDOT in 2014 through the Structures Design Guidelines (Section 3.12.7) (37) and Developmental Standard Index D6025 (38). Seven projects have utilized the system to-date with both prestressed slab beams and I-beam superstructure types. One of the more unique application was for the intermediate piers supporting a five-span precast-slab multi-use trail bridge crossing an intermittent floodway along US-301 near Dade City, FL. as shown in Figure 4. The design of a significantly more demanding application utilizing Florida-I beams on a GRS-IBS foundation with an integral diaphragm and bearing slab will be presented by Quan-Yang Yao et al. (2019) (39) at this conference.

Figure 4: GRS-IBS intermediate piers for multi-use trail along US301, under construction in 2016.

CONCLUSION Many ABC techniques related to PBES and GRS-IBS have been found to be advantageous for modest size bridge systems in Florida, and the number of applications and variations continuous to increase. Construction costs remain the predominant deterrent for broader ABC deployment on smaller projects, however the potential repetitive nature of longer bridges often offsets the higher mobilization, fabrication, erection and transportation costs, for improved project economy. Construction time savings are the predominant motivation for ABC PBES, with the potential for improved construction quality from precast components, reduced highway user delays, and reduced environmental disturbance. GRS-IBS advantages are attributed to the use of smaller construction equipment, foundation settlement tolerance, and the simplicity and speed of construction.

REFERENCES 1. Zollman, C. (1979), “Magnel’s Impact on the Advent of Prestressed Concrete, 25 Years of Reflections on the Beginnings of Prestressed Concrete in America”, Prestressed Concrete Institute, Chicago, IL, Part 1, pp.20-32, 1981 (reprint). 2. Fiore, M.E., and Hakman, P.A., (1955). “Sunshine Skyway Construction”, The Military Engineer Journal, No. 319, Sept-Oct 1955 pp 354-357. 3. Heller, J. (2000). “The Day the Skyway Fell, May 8, 1980”, St Petersburg Times Online, May 7. https://web.archive.org/web/20071017040518/http://www.sptimes.com/News/050700/TampaBay/ Horrific_accident_cre.shtml 4. Chandra, V. and Szecsei, G. (1988), “ Ship Impact Design of Low Level Approaches”, PCI Journal, V. 33, No. 4, July-August 1988, pp.96-123. 5. Tassin, D.M. (2006), “Jean M. Muller: Bridge Engineer”, PCI Journal, V. 51, No. 2, March-April 2006, pp.88-101. 6. Figg. (1999), “Garcon Point Bridge”, Bridge Portfolio – Long Bridges Over Water, FIGG Bridge Group, Tallahassee, FL. http://www.figgbridge.com/garcon_point_bridge.html 7. Figg. (1993), “Mid-Bay Bridge”, Bridge Portfolio – Long Bridges Over Water, FIGG Bridge Group, Tallahassee, FL. http://www.figgbridge.com/mid_bay_bridge.html 8. Moreton, A. J. (1989), “Segmental Bridge Construction in Florida – A Review and Perspective”, PCI Journal, V. 34, No. 3, May-June 1989, pp. 36-77. 9. Corven, J. (2002), “New Directions for Florida Post-Tensioned Bridges – Volume 1 of 10”, Corven Engineering Inc., for Florida Department of Transportation, Tallahassee, FL. https://www.fdot.gov/structures/posttensioning.shtm 10. Fisk, P. S. (2013), “Sonic/Ultrasonic Testing of Post Tensioning Ducts”, Wonderwood Bridge, Jacksonville, Florida, SR 116 over the Intracoastal Waterway. Report prepared for Florida DOT. NDT Corporation, Sterling, Mass. 11. Zhou, X., Di, J., and Tu, X. (2019), “Investigation of collapse of Florida International University (FIU) pedestrian bridge”, Engineering Structures, V. 200, December 2019. https://doi.org/10.1016/j.engstruct.2019.109733 12. Cao, R., El-Tawil, S., Agrawal, A.K. (2019), “Miami Pedestrian Bridge Collapse: Computational Forensic Analysis”, ASCE Journal of Bridge Engineering, Vol. 25, Issue 1, January 2020. 13. LoBuono, Armstrong & Associates, HDR Engineering Inc., Morales and Shumer Engineers, Inc., “Development of Precast Bridge Substructures”, Project No. 510703, FDOT, Tallahassee, FL, May 1996. 14. NCHRP. (2010), “Development of Precast Bent Cap System for Seismic Regions”, NCHRP Report 681, Transportation Research Board, National Research Council. 15. Nolan, S. (2014), “Precast Bent Caps and Full-Depth Deck Panels for US 90 over Little River and Hurricane Creek”, Proceedings: 2014 National Accelerated Bridge Construction Conference, December 4-5, 2014, Miami FL, pp.897-907. 16. Kampmann, R. (2015), “Rheology Limits for Grout Materials used for Precast Bent Cap Pile Pockets in Hot Weather”, FAMU-FSU College of Engineering for FDOT Research Contract BDV30 977-16, Tallahassee, FL. 17. FDOT. (2018), “Bent Cap v1.0 (Release Date 11/07/2018)”, Structures Programs Library, Florida Department of Transportation, Tallahassee, FL. https://www.fdot.gov/structures/proglib.shtm 18. Nolan, S. (2015), “FDOT Precast Bent Cap Development and Implementation”, Collection of Papers and Extended Abstracts 2015 National Accelerated Bridge Construction Conference, December 7-8, 2015, Miami FL, pp.71-84. 19. Garber, D. (2019), “Evaluation of Concrete Pile to Footing or Cap Connections”, Florida International University, for FDOT Research Project BDV29 977-51. 20. Sungmoon, J. Kampmann, R. (2018), “Evaluation of Glass Fiber Reinforced Polymers (GFRP) Spirals in Corrosion Resistant Concrete Piles”, FAMU-FSU College of Engineering for FDOT Research Contract BDV30 977-27, Tallahassee, FL. 21. Melarbi, A. and Farhangdoust, S. (2019), “Epoxy Dowel Pile Splice Evaluation”, Florida International University, for FDOT Research Project BDV29 977-52. 22. FDOT. (2018), Fast-Facts: US-441 over Taylor Creek. https://fdotwww.blob.core.windows.net/sitefinity/docs/default- source/structures/innovation/fastfacts/fastfacts_437984-1.pdf 23. FDOT. (2018), Fast-Facts: I-95 NB over CR 5A, https://fdotwww.blob.core.windows.net/sitefinity/docs/default- source/structures/innovation/fastfacts/fastfacts_438321-1.pdf 24. Roddenberry, M., Kampmann, R., Sobanjo. (2019), “Precast Element Evaluation for the US 90 Bridges over Little River and Hurricane Creek”, FAMU-FSU College of Engineering, FDOT Research Project BDV30-307-01, Tallahassee, FL. 25. FDOT. (2019), Fast-Facts I-10 over Flat Creek https://www.fdot.gov/structures/innovation/uhpc.shtm#Projects 26. FDOT. (2019), Fast-Facts I-10 over SR-267B https://www.fdot.gov/structures/innovation/uhpc.shtm#Projects 27. Littleton, P. and Mallela, J. (2014), “Florida Demonstration Project: Precast Concrete Pavement System on US92”, Applied Research Associates, Inc. for FHWA Highways for Life, Washington DC. https://www.fhwa.dot.gov/hfl/projects/fl_pcps_us92.pdf 28. Nolan, S. (2017), “Prestressed/Precast Florida-Slab-Beams for Robust Local Bridges and Accelerated Construction”. ABC-UTC webinar presentation, November 16, 2017. https://abc- utc.fiu.edu/webinars/webinar-archives/ 29. FDOT (2016), Florida Slab-Beams: Index D20450 series, Developmental Design Standards, Florida Department of Transportation, Tallahassee, FL. https://www.fdot.gov/roadway/DS/Dev.shtm#20450 30. FDOT (2016), FSB Superstructures Packages: Index D30000 series, Developmental Design Standards, Florida Department of Transportation, Tallahassee, FL. URL https://www.fdot.gov/roadway/DS/Dev.shtm#30000 31. Garber, D. (2016), “Florida Slab Beam Bridge with Ultra-High Performance Concrete Joint Connections”, Florida International University, FDOT Research project BDV29 977-28, Tallahassee, FL. 32. FDOT (2019), Fast-Facts: US41 over Morning Star Waterway. https://fdotwww.blob.core.windows.net/sitefinity/docs/default- source/structures/innovation/fastfacts/fastfacts-435390-1.pdf 33. FDOT (2019), Fast Facts: US41 over Sunset Waterway. https://fdotwww.blob.core.windows.net/sitefinity/docs/default- source/structures/innovation/uhpc/fastfacts_435390-1.pdf 34. FDOT (2019), Fast Facts: US1 over Cow Key Channel. https://fdotwww.blob.core.windows.net/sitefinity/docs/default- source/structures/innovation/fastfacts/fastfacts-441740-1.pdf 35. Cardno, FDOT (2019), Fast Facts: 40th Ave NE over Placido Bayou. https://fdotwww.blob.core.windows.net/sitefinity/docs/default- source/structures/innovation/fastfacts/fastfacts-443600-1.pdf 36. Roddenberry et al. (2017), “Stainless Steel Strands and Lightweight Concrete for Pre-tensioned Concrete Girders”, FAMU-FSU College of Engineering. FDOT Research Project BDV30 977-22, Florida Department of Transportation. 37. FDOT (2019), Structures Design Guidelines, Structures Manual – Volume 1, Florida Department of Transportation, Tallahassee FL. https://www.fdot.gov/structures/structuresmanual/currentrelease/structuresmanual.shtm 38. FDOT (2017), Florida Slab-Beams: Index D6025 series, Developmental Design Standards, Florida Department of Transportation, Tallahassee, FL. URL https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/roadway/ds/dev/d06025.pdf 39. Yoa, Q., Diggs, D., Jones, L., Patel, K. (2019), “Design of First Florida-I Beam Bridge with GRS Abutment”, Proceedings of the 2019 International Accelerated Bridge Conference (pending), Miami, FL, December 2019.