Enhancing Progressive Collapse Resistance of Building using Energy Dissipation Devices

Abstract

Progressive collapse denotes a failure of substantial part of the structure, causing greater damage to the structure than the initial damage. It is initiated by failure of a relatively small part of the structure such as failure of any vertical load carrying elements (typically columns). Failure of large part of any structure will results into substantial loss of human lives and natural resources. Therefore, it is important to prevent progressive collapse which is also known as disproportionate collapse. Generally, viscoelastic dampers are used for improving performance of building during earthquakes. In the present study, effect of viscoelastic dampers on progressive collapse re- sistance of 4-storey reinforced concrete frame structure, 4-storey reinforced concrete sym- metric building and 12-storey resendential building is evaluated. Three different damping i.e. 10%, 15% and 20% is considered for viscoelastic dampers. Linear static, Linear dy- namic, Nonlinear static and Nonlinear dynamic analysis are performed by following U. S. General Service Administration (GSA) and Department of Defense (DoD) guidelines for evaluating progressive collapse potential. Modeling and analysis is performed using SAP2000 for different threat independent column removal scenarios. Demand Capacity Ratio (DCR) is calculated using alternate load path method for linear static analysis. Lin- ear dynamic analysis is performed to obtain displacement at location of removed columns. Nonlinear Static (Push Down) analysis is performed for evaluating the progressive collapse load resistance capacity. Nonlinear dynamic analysis is carried out to obtain the vertical de ection at the location of column removal. From the analysis results, it is observed that viscoelastic dampers contributes in load resistance and enhances the performance of building during progressive collapse scenario. Also the vertical de ection at column removal location is decreased to significant level. It is also observed that DCR in beams and columns of buildings without dampers are exceeding the allowable limit i.e. 2 for exure and 1 for shear and column, which indi- cates high potential of progressive collapse. When viscoelastic dampers are used, DCR for beams reduces significantly, which indicates enhanced progressive collapse resistance of building. It is also evident that, displacement at the location of column removal is maxi-mum in case of building without dampers. After incorporating viscoelsatic damper with suitable damping, considerably reduces the displacement upto 50%-70% at the location of removed column. Viscoelastic dampers significantly increases load resistance capacity of structure with significant reduction in vertical de ection at the location of removed column. Formation of 1st hinge in the frames with viscoelastic dampers has 35%-70% more load resistance capacity as compared to frames without dampers. Similarly, load resistance capacity corresponding to collapse load increases by 40%-70% for frames with viscoelastic dampers as compared to frames without dampers.