Pounding Engineering

Abstract

In a dense urban setting, buildings are often placed closely to each other. In an event of an earthquake, two adjacent buildings with different natural period and motions could collide. It is typical that the design of the building would not account for the force induced by the collision. The result of one building pounding another can result in serious damages and even (catastrophic) collapse. There are two main sections to this paper, first is to explore the difficulties in modeling the forces and displacements due to impact in order to gain insights to the pounding issue. Second is to explore some mitigation methods and arrive at some design guidelines.

I Introduction

Early examples of significant damages due to pounding could be examined from the 1985 Mexico City earthquake (Scholl_1987 or Rosenblueth & Meli 1986) or the 1989 Loma Prieta earthquake (Kasai & Maison 1997). In the Mexico City earthquake pounding was responsible for 15% of the major damages.

Figure XX (damages)

Figure XX (Loma Prieta damages)

The theories related to the physic of impact are complex but simple model can be derived to understand the problem in a structural engineering and design stand point. In the following section we will explore different models used to simulate pounding and their validity. In addition, mitigation strategies would be discussed in the second section.

II How to Model Pounding

The pounding problem was fully recognized and addressed around the late 1980’s. To understand and design for pounding, one must first accurately model and predict the forces during impact. The earlier studies modeled each building is represented as a single-degree-of-freedom system. As computation power increase, research is capable of more complex models. All cases provide interesting insights to the issue.

a. Modeling Pounding with SDOF

Each building is represented as a single degree of freedom system (SDOF). In the simplest form, between the...