Linear and Nonlinear Progressive Collapse Analysis of Steel Structure

Abstract

Progressive collapse in a structure occurs when major structural load carrying members are suddenly collapsed due to abnormal or accidental loads. Generally buildings are designed for Dead loads, Live loads, Wind Loads and Earthquake loads but not designed for accidental loadings. Issue of progressive collapse of the building came in to attention after the collapse of Ronan Point Apartment, London in 1968. Since then many events like terrorist attacks, fire, gas explosion, faulty construction practice etc. became the causes of the progressive collapse of the entire or some parts of the structure. Hence various codes and guidelines of different countries have addressed this issue and made certain provisions to reduce the chances of progressive collapse of the entire structure. General Services Administration (GSA) guideline and Department of Defense (DoD) guideline are followed by engineers widely. In this paper, progressive collapse analysis of 4-storey moment resistant steel building using GSA guideline and DoD guideline is discussed. Linear static and dynamic analysis methods are followed for calculation of demand capacity ratio (DCR) for flexure for beams and for highly stressed nearby columns after the removal of load carrying elements. Non-linear static analysis procedure is carried out to understand the hinge formation pattern in the structure and corresponding plastic hinge rotations at the maximum collapse load after the loss of column. For progressive collapse analysis of the building SAP2000 software is used.