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Girder Bridge DESIGN AND BIOGRAPHY SUMMARY CONSTRUCTION Brandon Chavel is a Senior Located in southwest Illinois, OF A LONG SPAN Bridge Engineer and the new steel plate I-girder Professional Associate for HDR Chain of Rocks Bridge is STEEL PLATE I- Engineering in Cleveland, OH. designed to carry six total GIRDER BRIDGE: In his 12 years of experience he lanes of the I-270 corridor I-270 BRIDGE has been the lead structural over the main navigation engineer for several complex channel for Mississippi River OVER CHAIN OF bridge designs, construction barge and vessel traffic. The ROCKS CANAL engineering, and load rating new Chain of Rocks Bridge is projects. His highway and a five span continuous railroad bridge experience haunched steel plate girder includes completing bridge type bridge with spans of 250′, studies, curved girder bridge 440′, 490′, 440′, and 350′, and design, complex load rating, is one of the longest steel plate seismic design, erection girder bridges in the State of engineering, rehabilitation Illinois. The new structure design, and bridge research replaces twin steel truss studies. Dr. Chavel received is bridges that are now Ph.D. in civil engineering from functionally obsolete. the University of Pittsburgh, Several constraints associated where his graduate research with the Chain of Rocks work was in the area of curved navigation channel and steel I-girder bridge behavior adjacent levees, and roadway and construction techniques. BRANDON CHAVEL geometry resulted in the span Lance Peterman is a Senior arrangement and choice of a Structural Project Manger and steel girder superstructure. All Professional Associate for HDR superstructure steel is Engineering in Chicago, IL. unpainted weathering steel, Mr. Peterman has been and an efficient combination responsible for directing the of Grade 50W and HPS70W is design of several complex utilized for the various girder bridge and transportation sections. The bridge cross projects. He has more than 23 section consists of 10 equally years of experience in the spaced steel plate girders, planning, design, and which support the 94’-2” wide construction of highway and cast-in-place concrete deck. railroad bridges, rapid transit The steel plate girders are structures, and retaining walls, haunched to maximize as well as design-build projects. structural efficiency in the LANCE PETERMAN Mr. Peterman is a registered negative moment regions. Structural Engineer in Illinois, The paper will discuss the and received both his challenges faced during the Bachelor’s and Master’s Degree design and construction of the in Civil Engineering from the long span I-270 Chain of Rocks University of Illinois Urbana- Bridge. The design and Champaign. construction of a long span I- girder bridges can be complex, however when all of the issues are addressed, the end result is a successful and efficient steel girder bridge. DESIGN AND CONSTRUCTION OF A LONG SPAN STEEL PLATE I-GIRDER BRIDGE: I-270 BRIDGE OVER CHAIN OF ROCKS CANAL Introduction each of the structures is just less than 2000 feet. Each existing bridge accommodates two 12′-0″ wide I-270 is a four-lane interstate expressway that serves lanes and 3′-0″ wide shoulders. The existing bridges as a north bypass to the City of St. Louis. I-270 are structurally deficient and functionally obsolete, carries a significant number of daily commuters two-lane structures that have insufficient width between Illinois and Missouri with an average shoulders. The structures were deteriorating at an annual daily traffic count of 54,700 vehicles and accelerated rate and this lead to an increase in the 20% truck traffic. This project includes a complete frequency of bridge repairs. The floorbeams and the reconstruction of a pair of truss bridges over the deck were in poor condition and required recurring Chain of Rocks Canal with a single bridge on a new repairs. The maintenance activities caused alignment north of and adjacent to the existing significant disruption to traffic since a lane had to be bridges. taken out of service during these operations. The The Chain of Rocks Canal provides a bypass for all gusset plates throughout the truss were evaluated Mississippi River barge traffic in the region that is given the recent collapse of I-35 in Minnesota and necessary due to the rock outcrop in the portion of found to be satisfactory. Additionally, the existing the river in the vicinity of I-270. The canal is open bridges are located in a Seismic Performance Zone 2 to the main channel of the Mississippi River on the and did not satisfy current seismic ductility upstream end, and it is controlled on the downstream demands. end by Lock and Dam 27. The St. Louis District of the U.S. Army Corps of Engineers owns and operates the Chain of Rocks Lock #27. On average over 70 million tons of cargo pass through Lock #27 a year making it the busiest navigation structure on the Mississippi River. Parallel to the canal on the west is a saddle dam and to the east is a major flood protection levee. The Figure 1: Existing I-270 Bridges Over the Chain of Chain of Rocks east levee is a critical link in the Rocks Canal overall Mississippi River levee system, providing 500 year flood protection to Illinois residents in an The existing bridges are currently being replaced 85,000 acre area. The United States Army Corps of with a haunched steel plate girder bridge with a total Engineers (USACE) prohibits any construction length of 1970′. The proposed structure consists of 5 activity that would impact the integrity or function continuous spans: 250′, 440′, 490′, 440′, and 350′, as of the east levee as the flood protection function shown in Figure 2. The span arrangement was cannot be comprised. dictated by the need to span the canal and adjacent east flood protection levee. The bridge is 94’-2” The existing I-270 bridges are over 50 years old and wide and can accommodate a future lane consist of two identical 12-span bridges (see Figure arrangement of 6 total lanes. The bridge consists of 1). Each bridge has four approach spans at the west 10 variable depth steel plate I-girders. Scheduled to end and five approach spans at the east end. The be complete in 2014, the new I-270 bridge approach spans are constructed of continuous steel represents the largest steel plate I-girder bridge in plate multi-girders. The main spans over the canal Illinois. consist of three-span cantilevered through trusses with a suspended span over the canal. The main span over the canal is 480′-0″ and the total length of Page 1 of 12 Figure 2: Plan and Elevation Drawing of the new I-270 Bridge over the Chain of Rocks Canal Bridge Type Study either span the existing levee or include provisions to relocate the levee to avoid conflicts between The design and construction of the new I-270 bridge proposed piers and the east levee. An access road had to consider the navigation requirements of this located on the levee had to remain open at all times canal. The United States Coast Guard (USCG) for USACE maintenance and emergency response. required the proposed bridge to provide a 350 foot The centerline of the flood protection levee is horizontal navigational clearance in line with the approximately 400 feet east of the canal. The cross existing bridge opening and that the vertical section of the levee is a 20 foot wide crown with 1:4 clearance match that provided by the existing I-270 side slopes. In order to open up the bridge type bridges. The vertical clearance from low steel to the study to multiple alternatives it was proposed that 50 year high water level is less than 50 feet. Barge the existing levee be left intact and that a new traffic in the canal operates 24 hours a day, 7 days a parallel levee embankment be constructed. This new week, and year-round. A reduction in the 350 foot levee arrangement allowed proposed bridge piers to horizontal clearance was permitted by USCG during penetrate the existing levee but not the footprint of construction. The minimum temporary horizontal the proposed parallel levee. clearance was 200 feet. This temporary horizontal clearance accommodated one shipping vessel The vertical and horizontal alignments of the passing under the structure as well as the pier proposed bridge are interrelated to the IL Route 3 cofferdams and 35 foot wide working barges. These interchange located approximately three-fourths of a temporary horizontal clearance requirements were mile to the east of the Chain of Rocks Canal. considered when determining the main span length Accommodating the westbound entrance ramp of of the new bridge. this interchange with the proposed westbound alignment of I-270 was a significant design The spans adjacent to the main span had to consider constraint. The new bridge had to accommodate two the structural efficiency of the continuous structure lanes of traffic in each direction and be compatible as well as the west saddle dam and east flood with a future I-270 corridor widening project. protection levee. Bridge replacement options had to Page 2 of 12 The bridge type study commenced with a design of span length flexibility was not cost justified. A charrette meeting. Key decision makers from the five span continuous plate girder bridge was Illinois Department of Transportation (IDOT) and selected. The superstructure was supported with the Federal Highway Administration (FHWA) met solid wall piers on drilled shafts on either side of the with the HDR consultant team to review and discuss canal, with multi-column pier bents on drilled shafts detailed information pertaining to the existing supporting adjacent interior spans, and with open structures and design alternates to help expedite a abutments on both ends supported on metal shell consensus on the alignment and bridge types to carry piles.
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