PBES Innovative Projects

By Advantages : Improve Construction Zone Safety

IH70/Lake St. Louis Boulevard Bridge
Location	IH70 over Lake St. Louis Bridge in St. Charles County
State	MO
Completion Date	2003
Contact Person	Ghanshyam Gupta, P.E., Missouri Department of Transportation, (573) 751-4676
Description	To reduce congestion on the IH70/Lake St. Louis Boulevard Bridge in St. Charles County, the Missouri Department of Transportation opted for widening it and then accepted a contractor's value-engineering proposal to rebuild the bridge using prefabrication, replacing the four-span bridge with two spans. Although costs increased, the proposal offered both short- and long-term benefits. Work on the new bridge completed in late 2003. The new bridge used precast deck and beam sections and puzzle wall abutments, which allowed a design with fewer spans. With the prefabrication redesign, MoDOT reduced construction time by several months. By reducing the number of spans, geometrics of the interchange improved, increasing its safety and efficiency. Fewer spans also result in lower maintenance costs. By eliminating the need for formwork, which would have reduced clearance on IH70 but was required for a widening in place of the old bridge, the value-engineering proposal using prefabrication greatly improved work zone safety by reducing the amount of time workers had to operate in low-clearance conditions. With prefabrication facilitating faster construction, bridge users were spared several months of inconvenience, and IH70 users were spared a period of reduced vertical clearance. Motorist safety increased because falsework towers were not needed in the outside shoulders. Additionally, the new structure is more aesthetically appealing.
Prefabricated Elements	Decks
Other Keywords	precast deck panels (lightweight)
Advantages	Minimized traffic disruption, work-zone safety
Lewis and Clark Bridge
Location	SR 433 across the Columbia River between Oregon and Washington State
State	WA
Completion Date	2004
Contact Person	Jerry Weigel, P.E., Washington State Department of Transportation, (360) 705-7207
Description	This full-depth precast deck replacement was for a steel truss bridge 5,478 ft. long and 34 ft. wide with 34 spans. A joint project by the Oregon and Washington Departments of Transportation to widen and replace the deteriorating deck on this historic 1929 steel truss bridge allowed full closures between 9:30 pm and 5:30 am for only 120 nights, plus 4 weekend closures. Alternative plans to replace the bridge deck would have required replacing it lane by lane (4 years), full closure of the bridge for several months, or full closure every weekend for 6 months. The contractor was able to meet scheduling constraints by using prefabricated deck panels-a large transport device moved the new panel to the top of the bridge, removed the old panel that crews had just cut out, and then lowered the new panel into place before taking the old panel off the bridge. Work will be completed by December 2004. The majority of the existing bridge deck was replaced with precast concrete deck panels made of lightweight concrete with a modified concrete overlay supported by two longitudinal steel stringers with intermediate transverse stringers. The bridge also used prefabricated widening sections supported by a single longitudinal steel girder. In addition, the project included precast approach slabs. Oregon and WS DOT extended the life of the bridge by an estimated 25 years. In addition, prefabrication allowed inspection of the new deck before installation without use of specialized equipment. For Max J. Kuney Company of Spokane, use of prefabricated elements and systems reduced workers exposure to traffic during construction and improved the constructibility of the bridge. Use of prefabrication allowed the bridge to remain open for normal weekday operation, particularly important for traffic related to the Port of Longview.
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Prefabricated Elements	Decks
Other Keywords	full-depth deck panels
Advantages	Minimized traffic disruption, constructibility, work-zone safety
Photo Credits	Washington State Department of Transportation
SH 66 over Lake Ray Hubbard
Location	Near Dallas
State	TX
Completion Date	2002
Contact Person	Lloyd M. Wolf P.E. Design Branch Manager Bridge Division Texas Department of Transportation 125 E. 11th Street Austin TX 78701 Phone: (512) 416-2279 Fax: (512) 416-2557 Email: lwolf@dot.state.tx.us
Description	After 40 years of service, the narrow two-lane crossing of SH 66 over Lake Ray Hubbard had become a congested route for commuters in the suburbs east of Dallas and needed to be replaced. In 2000, construction began on a pair of conventional prestressed concrete I beam bridges with lengths of 10,280 and 4,360 feet. After the project was let for construction, the contractor asked to precast the substructure bent caps as an alternative to the original design of cast-in-place multi-column bents to reduce the amount of time the workers would need to operate near power lines. TxDOT designed a precast bent cap option that included a cap-to-column connection and a specific construction procedure that allowed early placement of caps and prestressed beams based on achieved cap concrete and cap grout connection strength. The connection design included reinforcing steel dowel bars that protrude from the columns into the precast caps via open plastic ducts that are grouted after cap placement. On this project a total of 43 bent caps will be precast.
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Prefabricated Elements	Bent caps; decks
Other Keywords	Precast bent caps; precast prestressed deck panels; precast prestressed I-beams
Advantages	Work zone safety: reduced amount of time required for work near power lines and reduced work time overwater (80% of work on caps was done on the ground).; Minimized traffic disruption: Using precast caps produced a saving of 5-7 days per cap, distributed across activities associated with formwork, curing, steel, inspection, and bearing seats.; Improved constructibility.
Related Document 1	Precast Bent Cap Column (Square and Round) Drawings (PDF, 0.6 mb) HTML Version: Sheet 1 - Square Sheet 2 - Round
Related Document 2	Precast Bent Cap Detail Drawings (PDF, 0.9 mb) HTML Version: Sheet 1 Sheet 2 Sheet 3
Photo Credits	Texas Department of Transportation
SH 66 over Mitchell Gulch
Location	SH 66 over Mitchell Gulch between Franktown and Castle Rock
State	CO
Completion Date	2002
Contact Person	Wes Goff P.E. Phone: (303) 757-9116 Email: wes.goff@dot.state.co.us
Description	Originally designed as 3 box culverts, the Colorado Department of Transportation accepted a value-engineering proposal for this replacement bridge to minimize traffic impact. The alternate structure has a single span with side-by-side precast slab girders welded onto precast abutments and wings welded to driven-steel H piles. Piles were driven in advance outside the existing bridge. Railing was precast into the outside girders. Except for the steel H-pile supports, the entire bridge substructure was composed of precast concrete elements. Each abutment consisted of a lower and upper backwall unit. Each of the four wingwalls for the bridge was a separate precast piece. The precast substructure units were attached in the field by welding together embedded plates precast into the elements. The bridge superstructure consisted of eight precast deck girder units each 5'-4" wide, 1'-6" deep, and 38'-4" long. The deck girders were placed on the completed abutments and then transversely post-tensioned and grouted together. The outside deck girders were constructed with integrated bridge railing to avoid the need for a separate railing installation operation in the field. Construction detours as a result of this project were reduced by the value-engineering proposal from an estimated two-to-three months to less than 48 hours.
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Prefabricated Elements	Total superstructure systems; bent caps
Other Keywords	Precast railing, precast retaining walls,totally prefabricated bridges
Advantages	Minimized traffic impact, improved work-zone safety by reducing work-zone time from several months to a weekend.
Related Document 1	Construction Photos (PDF, 0.4 mb) HTML Version
Photo Credits	Colorado Department of Transportation