St. Anthony Falls Bridge By: Timothy Brewer

St. Anthony Falls Bridge Backround Location: Minneapolis, Minnesota Design: Steel Truss Arch Bridge I-35 W, 8 Lanes of Traffic Total Length: 1,907 feet/ Width/Height: 113.3/115 ft Beginning Date Of Construction: 1964 Completed: November 1967

Construction Designated Bridge 9340 Sverdrup & Parcel designed the bridge in 1961 Hurcon Inc. and Industrial Construction Company were given the building contracts Contracts were worth more than 5.2 million dollars at the time Construction began in 1964

Opened in 1967

The Collapse

August 1, 2007 At 6:05 p.m. CDT, the central span of the bridge suddenly gave way, thus followed by its adjoining spans. The south part of the bridge went 81 ft eastward when it collapsed, while the northern parts landed on 3 freight cars in a ship yard. A state of emergency for the city of Minneapolis was declared the next day, August 2 nd. Navy divers began arriving on August 5 th to survey the wreckage from underneath.

Victims and Survivors 13 people were killed (8 males, 5 females) A school bus carrying 60 children rested against a guardrail of the collapsed structure. 1 youth worker was severely injured and 10 Children had minor injuries. During the first 40 hours, 11 area hospitals treated 98 victims

Causes of the Collapse html?elr=KArksi8D3PE7_8yc+D3aiUo8D3PE7_ eyc+D3aiUeyc+D3aUU Thin or undersized gusset plates Added weight over the years Equipment on the bridge

Fractured Gusset Plate

Reconstruction

Reconstruction Information Figg Bridge Engineers & Flatiron Constructors Inc. were given the new building contract Cost for the new bridge was around 9 million dollars 339 days to complete By completing the bridge, it helped the overall traffic problem seeing as 140,000 cars on average traveled across it on any given day.

New Design, Techniques, and Materials Foundation Consists of drilled shafts Four for each of the eight central span piers Each has a steel casting over concrete Pier Construction Each pier will be cast on-site atop the footings on each bank. Superstructure Construction Temporary scaffolding and forms will be built to provide a mold for the parts of the bridge over land.

Design, Techniques, and Materials Cont. Segment Placement The center spans box girder segments are precast and will be fitted by lowering them from a crane. Assembly Segments are linked together by steel cables threaded through them, with each segment linked to the adjacent ones and full-length cables linking the entire array. Final Segment After all the segments are in place, the final gap between the assembled sides is cast in concrete, completing the central span.

New I-35W Bridge 100-year life span 10 lanes of traffic, five in each direction—two lanes wider than the former bridge 1,223 feet long, 684 feet less than the previous. 189 feet wide—the previous bridge was 113 feet wide 13 foot wide right shoulders and 14 foot wide left shoulders, the previous bridge had no shoulders Light Rail Transport-ready which may help accommodate future transportation needs

Additional Information The completed bridge incorporates "Smart Bridge" technology to enhance bridge inspections and assist in the advancement of bridge design. In a partnership between Mn/DOT, the Federal Highway Administration, and the University of Minnesota, over 320 sensors throughout the structure monitor the bridge behavior. These include vibrating wire strain gages embedded in the concrete of the foundations, piers and superstructure, long gauge fiber optic strain gauges, accelerometers, linear potentiometers, and corrosion potential sensors embedded in the wearing surface.