Energy Dissipation in 3D Structure having Multiple Uplifts During Dynamic Loading
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RESEARCH ARTICLE-CIVIL ENGINEERING
Energy Dissipation in 3D Structure having Multiple Uplifts During Dynamic Loading Hassam Ud Din1 · Irfan Waris1 · Osama Bin Rizwan1 · Majid Ali1 Received: 14 July 2020 / Accepted: 7 October 2020 © King Fahd University of Petroleum & Minerals 2020
Abstract Uplift has been used as a mitigation measure to reduce lateral forces in structures. Previous studies had focused mainly on the effect of single column uplift with complex mechanism (particularly in three-dimensional structure) and favourable results were obtained. There is a need to explore consequence of multiple uplifts to be provided with simple technique. Uplift provision can be made with different mechanisms and one simple option can be loosening of bolt, which could be an effective and cost-efficient solution. The objective of this study is to investigate the effect of multiple uplifts (i.e. loosening of bolts) at column bases of a 3D single-storey prototype structure for possible energy dissipation under harmonic loading of different frequencies using simple unidirectional shake table. The basic dynamic properties (fundamental frequencies and damping ratios) are also experimentally determined using snapback test. Structure consists of four aluminium angle columns and a steel slab. Acceleration time histories are recorded in both types of tests. The influence of multiple uplifts at diagonal column bases as compared to fixed base and single uplift in structure is investigated. Finite element model is also established in SAP2000 for the prototype structure. The comparison reveals good agreement between the experimental and numerical results. During shake table tests, the multiple uplifts at column bases have dissipated more energy up to 91% and 25% as compared to the fixed base and single uplift, respectively. It is also found that the damping of the structures with multiple uplifts (11.61%) is higher than that of the structures with fixed base (4.86%) and single uplift (9.92%). As results of single-storey structure are favourable, multi-storied structure may also be explored. Keywords Single uplift · Multiple uplifts · 3D prototype structure · Shake table · Energy dissipation
1 Introduction 1.1 Damages in Structure During Past Earthquakes Earthquake is an unforeseeable and unavoidable catastrophic event that can cause serious structural damage and can take many lives. Pakistan is a country that is seismically vulnerable and has a history of past devastating earthquakes. In the past, the most prominent earthquake events such as the 7.4 magnitude Quetta earthquake in 1935, the 8.0 magnitude Makran earthquake in 1945, the 6.0 magnitude Pattan earthquake in 1974 and the 7.5 magnitude Kashmir earthquake in 2005 indicate strong seismicity [1, 2]. Bhagat et al. [3], Shakya et al. [4], and Thapa and Pathranarakul [5]
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Majid Ali [email protected] Department of Civil Engineering, Capital University of Science and Technology (CUST), Islamabad, Pakistan
investigated the Gorkha, Nepal earthquake of 25 April 2015 (MW 7
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