ENGINEERING LESSONS: EPISODE 21 DWARKA EXPRESSWAY GIRDER COLLAPSED
EPISODE 21: REPORT ON DWARKA EXPRESSWAY GIRDER COLLAPSED
Dwarka Expressway way, Package 3 bridge collapse 28/03/2021
Contractor: LNT, Engineer: AECOM, CEG
Contractor: LNT, Engineer: AECOM, CEG
As per VK Raina Report: Inspection of the Collapsed Spans of decks of Dwarka Gurgaon Bridge one almost fully prestressed and the other ready on hooks about to be prestressed.
Its observed that the Concrete surface at the bottoms of 2 segments was of very poor quality and fully honey combed, which got progressively Crushed in a matter of a minutes. The soffit commenced crushing, progressively reducing the effective compression section area that in turn commenced folding (upwards) , cracking open the top of top slab in Flexural Tension and the speeding and continuous reduction of effective section progressively Crushed the soffit, this 1st Plastic Hinge would Rotate fast enough not allowing the 2nd distressed section to catch up to form its Hinge. The rest is history. In the process the Launching Girder leg lost its support which the collapsing deck was providing, and went too. The adjoining deck segments, hanging in the Hooks in the LG had no choice but follow.
The entire act took just a few seconds as would be expected under classical flexural failure.
Along with the above reasons, some addons observed, No Epoxy in the Joints between adjoining segments, improper placed Bearing Plates at Anchorages so much so that some of these Thick Steel Plates
Absence of Epoxy at Joints between p/c segments will have an adverse effect on Ultimate Shear Behavior of the Decks.
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