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
Slide 4
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
Slide 5
Opened in 1967
Slide 6
The Collapse
Slide 7
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.
Slide 8
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
Slide 9
Causes of the Collapse
www.startribune.com/newsgraphics/13820902.
html?elr=KArksi8D3PE7_8yc+D3aiUo8D3PE7_ eyc+D3aiUeyc+D3aUU Thin or
undersized gusset plates Added weight over the years Equipment on
the bridge
Slide 10
Fractured Gusset Plate
Slide 11
Reconstruction
Slide 12
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.
Slide 13
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.
Slide 14
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.
Slide 15
New I-35W Bridge 100-year life span 10 lanes of traffic, five
in each directiontwo lanes wider than the former bridge 1,223 feet
long, 684 feet less than the previous. 189 feet widethe 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
Slide 16
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.
