Performance of ultra-high performance concrete shear walls subjected to wind and windborne debris impact
Date
2023-08
Authors
Kulkarni, Abhijit
Major Professor
Advisor
Shafei, Behrouz
Alipour, Alice
Cho, In Ho
Jahren, Charles
Dayal, Vinay
Committee Member
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Abstract
In general, buildings are designed to resist multiple loads during their service life and survive during major hazards. There are a limited number of studies directed towards the performance of concrete shear walls when the concrete shear walls are subjected to impact, in-plane lateral loads, and their post-impact lateral load resisting capacity. Also, newer materials such as ultra-high-performance concrete (UHPC) are making their way to widespread usage in the construction industry. Thus, it is crucial to assess the behavior of walls made up of such high strength concrete. Extensive research related to conventional concrete structures subjected to impact and lateral loads has been carried out. However, no systematic study on the post-impact performance assessment of conventional concrete is available. Besides, the use of ultra-high-performance concrete in shear walls has seen little progress. To address this research gap, the current research focusses on the analysis of UHPC and conventional walls under impact loading, behavior of UHPC and conventional concrete shear walls under lateral loads, and post-impact performance of UHPC and conventional concrete shear walls subjected to lateral loading.
The ultra-high-performance concrete not only reduces the cross-section of the structural component, but its increased strength also assures near-absolute protection when impact due to standard wind-borne debris missiles was investigated. However, UHPC has not been used in concrete shear walls before. There is a little research carried out on the behavior of scale specimens of UHPC shear walls under lateral loads. Such research does not provide holistic and realistic behavior and ultimate capacities of shear walls. For this purpose, full-scale high-fidelity physics-based computation models are developed using commercial finite element package LS-Dyna. In the first and second stage, the conventional concrete walls and UHPC walls were separately analyzed under the debris impact load, and cyclic lateral load, respectively. For the purpose of studying the behavior of shear walls under debris impact, the effects of a wide range of parameters, including the impact velocity, weight of the missile, thickness of the wall, contribution of reinforcement, and type of concrete (Normal strength and UHPC), are examined. For the purpose of studying the behavior of shear walls under lateral loads. The effects of a wide range of structural parameters, including thickness of wall, aspect ratio, percentage of reinforcement, presence of boundary elements, strength of embedded reinforcement, and types of concrete (Normal strength and UHPC) are examined. In the third stage, the performance of UHPC and conventional concrete shear walls are assessed after the impact of wind-borne debris. In this stage the study is further expanded to quantify the damage of UHPC and conventional concrete shear walls by evaluating their post-impact lateral load carrying capacity.
The outcome of this study is expected to pave the way for transition from conventional concrete shear walls to UHPC shear walls at key locations. The outcome of this research is also expected to provide the 1) knowledge required in the development of the infrastructure to protect it from threats of wind-borne debris missile impacts 2) the applicability of UHPC shear walls in critical structural components 3) an understanding of post-impact behavior of UHPC and conventional concrete shear walls.
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Type
dissertation