Numerical simulation of base-isolated buildings in collisions with surrounding moat walls during earthquakes: a nonsmoot

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Numerical simulation of base‑isolated buildings in collisions with surrounding moat walls during earthquakes: a nonsmooth mechanics approach Shota Fukasawa1 · Yoshihiro Kanno2 Received: 24 August 2019 / Revised: 13 December 2019 / Accepted: 13 December 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract In this paper, we present a formulation and a numerical simulation method for earthquake-induced collisions between a seismically base-isolated building structure and its surrounding moat walls. The base isolator is assumed to undergo plastic deformation. We use the conventional shear building model for a superstructure. Based on nonsmooth mechanics, we formulate a measure differential inclusion that describes the time evolution of the entire structure. For numerical computation, we apply Moreau’s time-stepping scheme to the presented formulation. As a consequence, we solve a quadratic programming problem for each time-step. Our preliminary numerical experiments demonstrate that the presented method is more robust and numerically stable compared with the conventional Newmark method. We also present two numerical examples of mid-rise base-isolated building structures. Keywords  Seismic pounding · Base-isolated building · Nonsmooth mechanics · Linear complementarity problem · Quadratic programming · Measure differential inclusion

1 Introduction Pounding induced by earthquakes can cause serious damages to structures (Nagarajaiah and Sun 2001; Chouw and Hao 2012; Rojas and Anderson 2012). This paper presents a numerical method for simulation of earthquake-induced pounding of seismically base-isolated building structures.

* Yoshihiro Kanno [email protected]‑tokyo.ac.jp 1

Department of Architecture and Building Engineering, School of Environment and Society, Tokyo Institute of Technology, Nagatsuta 4259, Yokohama 226‑8503, Japan

2

Mathematics and Informatics Center, The University of Tokyo, Hongo 7‑3‑1, Tokyo 113‑8656, Japan



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S. Fukasawa, Y. Kanno

There exists a vast literature studying seismic pounding of base-isolated building structures; see Agarwal et al. (2007), Kashiwa et al. (2005), Masroor and Mosqueda (2012), Matsagar and Jangid (2003), Miwada et al. (2011), Nakazawa et al. (2012), Pan et  al. (2004) and Komodromos et  al. (2007), Polycarpou and Komodromos (2010a, b), Kanno et al. (2017) and the references therein. Attention of this paper is focused on collision between a building and its surrounding moat wall. However, the proposed formulation and numerical method are versatile, in the sense that extension to collision between two adjacent structures (Matsagar and Jangid 2003; Polycarpou and Komodromos 2010a, b; Wolf and Skrikerud 1980; Komodromos et al. 2007; Anagnostopoulos 1988) is straightforward. Numerical simulation of seismic pounding of base-isolated buildings and surrounding moat walls has been studied extensively as follows. Matsagar and Jangid (2003) performed parametric study of the impact response with respect to variation of the width