Study on Progressive Collapse of Precast Connections

One of the major causes for failures of many structures around the world is extreme loading effects generated due to hurricane, flood, earthquake, explosion and terrorist attacks on buildings imposing abnormal loading on the building structure. The major reason of collapse of building is they are not resistant to this type of abnormal loading which is referred as “Progressive Collapse”. Progressive collapse of any structure causes catastrophic failure of structure leading to substantial loss of human lives as well as natural resources.

Precast technology is faster, provides better quality, easier for large scale construction of buildings and other structures. Further, it also helps in achieving sustainability by reducing consumption of natural resources and possible reuse after design life. The success of the precast structures is mainly dependent on the “connections”.

It has been observed in the past that failure of the connections were chiefly responsible for collapse of precast structures. Hence it is required to study the performance of connection between precast elements under a progressive collapse scenario.

Dr P V Patel, Civil Engineering Department, Nirma University shared that, the progressive collapse resistance of precast concrete structures is less explored till date and therefore, he along with his colleague Prof D D Joshi, conducted the research project entitled “Study the Behaviour of Precast Beam-Column Junction under Progressive Collapse Scenario: An Experimental and Analytical Investigation” funded by Science and Engineering Research Board (SERB), New Delhi.

In this study, behaviour of different precast connections are evaluated under progressive collapse scenario by conducting experiments and performing numerical analysis and are compared with monolithic counterpart. From the experimental results, it is observed that, precast wet connections performs superior as compared to precast dry connections under progressive collapse scenario.

Moreover, it was also assessed by the numerical analysis done by ABAQUS software. Finite Element models (FE models) developed for precast connections under progressive collapse scenario, using concrete damage plasticity model are capable to capture the behaviour of specimen and their results were similar to the experimental studies.

Dr P V Patel, principal investigator says, “Precast structures designed and constructed with adequate connection detailing and continuity between different precast elements within connection region, performs similar to that of cast-in-situ structure and may be considered as an effective alternative to conventional cast-in-situ construction.”