Bridge Name ():Silver Bridge()Location ():West Virginia, USA
()Bridge Completion () :1928 (1928)Collapse Date ():December 1967
(196712)Cause of Collapse():Failure of Structural Steel due to
Corrosion()
Bridge Name (): I-35W Mississippi River Bridge (I-35W)Location
():Minnesota, USA ()Bridge Completion ():November 1967
(196711)Collapse Date ():1 August 2007 (200781)Cause of Collapse
():Investigation underway (concern had been emphasized on possible
flaw at truss girders)()
()ULS Displacement = 4.35 mSLS Displacement = 2.90 mHourly Mean
Wind Speed at Deck Level (m/sec)Lateral Displacement at Mid-Span
(metre)
Note : Each set of Suspender is composed of 4 Nos. 75 mm dia.
Hanger Strands.ULS Material Strength= 617 tonsSLS Material
Strength= 448 tonsULS Design Load= 500 tonsTension Load during
Erection Stage()()SLS Design Load= 435 tons
(Fatigue Monitoring)Ma Wan TowerMa Wan AbutmentTsing Yi
TowerTsing Yi AbutmentCHAINAGE 23623.0Partial Elevation View at
Chainage 23623.00Sectional View at Chainage
23623.00NorthSouthCHAINAGE 23623.00
>> ,Fatigue stress concentration factor 1.4BS-5400: Part
10 r N Curves Class FHalf-Cycles CountsSTRESS (N/mm2)
15.2.2006
100% 100% 281m 246m 23/65 29/224 30.4.2008
2008
2008
2009
35****The truck for the testing is a 1994 ERF multi-axle rigid
tipper lorry.MassCGRigid, 8 wheel trucks with twin steerThe CG is
estimated by assessing the masses and CG heights of major vehicle
components and taking moments about ground level.
The critical issue here is about vortex shedding. When wind
blows at a certain speed, along the bridge axis, the tower will
vibrate in the across wind direction as a result of vortex
shedding.
The picture shows the model set up in the Velux tunnel in
Denmark. As the tower is about 300m high, a 1:100 geometric scale
will lead to a 3m high model.
3535This shows the inner components of a heavy composite option.
The outer structural steel skin which is 20mm thick. The inner
reinforced concrete wall which is 800mm thick. These two components
will be connected by shear connectors. The steel anchor box for
stay cables will also be connected to the concrete wall by shear
connectors.In order to enhance durability of the metallic finishes
of the skin, it has been decided to use stainless steel shell
instead of ordinary steel. A 1:1 prototype was fabricated to
demonstrate the achievability of a good finish of the prefabricated
steel units***********
