Failure Analysis at DMRC
On July 12th 2009 a metro bridge that was under construction collapsed due to negligence by an office in-charge of the Badarpur Metro line. The failure of the bridge killed 6 and injured another 15 when the pier cap sheared from the connecting pillars. The Delhi Metro Rail Corporation took major heat from this incident because the roadway was a major milestone of providing a reliable and easy mean of transportation to the capitol of India. The DMRC is considered the most reputed infrastructure organization of India and neglecting roadways to the point where they fail is not an option.
During that day the pier cap collapsed causing the collapse of the launching girder, span between p-66 and p-67 piers which had already been erected and pre-stressed, and also segments of the superstructure for the span between p-67 and p-68. The pier cap (p-67) sheared from the connecting point of the pier and pier cap. The top reinforcement of the cantilever beam did not have any development into the pier itself which caused the shear itself. The launching girder has failed due to the failure of the pier cap. This failure also caused the span between piers 67 and 68 causing it to be inclined supported by the ground on one end and the pier cap on the other. With the failure of the pier cap and span between piers the crane used for lifting the launching girder also failed on July 13th 2009. Bending of the crane shows the clear sign of overloading which was caused by not analyzing the amount of stress the crane could handle. The causes of the failure are many and once one portion of the roadway failed it caused a chain reaction to the entire infrastructure collapsing. The pier (p-67) was initially designed as a leg of a portal frame between piers but then was changed to support the pier cap. The same method was used for piers p-66 and p-68. The top reinforcement was poorly engineered; the pier cap had a reinforcement of 36mm diameter and a length...
Please join StudyMode to read the full document