On the Design of High-Rise Buildings for Multihazard: Fundamental Differences between Wind and Earthquake Demand

Aly Mousaad Aly,Srinivasa Abburu

doi:10.1155/2015/148681

Abstract

In the past few decades, high-rise buildings have received a renewed interest in many city business locations, where land is scarce, as per their economics, sustainability, and other benefits. Taller and taller towers are being built everywhere in the world. However, the increased frequency of multihazard disasters makes it challenging to balance between a resilient and sustainable construction. Accordingly, it is essential to understand the behavior of such structures under multihazard loadings, in order to apply such knowledge to design. The results obtained from the dynamic analysis of two different high-rise buildings (54-story and 76-story buildings) investigated in the current study indicate that earthquake loads excite higher modes that produce lower interstory drift, compared to wind loads, but higher accelerations that occur for a shorter time. Wind-induced accelerations may have comfort and serviceability concerns, while excessive interstory drifts can cause security issues. The results also show that high-rise and slender buildings designed for wind may be safe under moderate earthquake loads, regarding the main force resisting system. Nevertheless, nonstructural components may present a significant percentage of loss exposure of buildings to earthquakes due to higher floor acceleration. Consequently, appropriate damping/control techniques for tall buildings are recommended for mitigation under multihazard.

Highlights

Wind and seismic hazards, coupled with aging and vulnerable buildings, pose the potential for damage and loss of life and property
The nature of the two loads is totally different from the static load, and even if they could be expressed as equivalent static loads, tall buildings and flexible structures may amplify the internal loads resulting in additional inertia loads which can alarm the serviceability and the comfort concern of people in a building or even lead to a complete collapse
It is important to mention that, even if the interstory drift ratios in tall buildings may be relatively small with no significant risk issues for the main force resisting system of the structure, nonstructural systems represent a high percentage of loss exposure of buildings to earthquakes

Summary

Introduction

Wind and seismic hazards, coupled with aging and vulnerable buildings, pose the potential for damage and loss of life and property. The nature of the two loads is totally different from the static load, and even if they could be expressed as equivalent static loads, tall buildings and flexible structures may amplify the internal loads resulting in additional inertia loads which can alarm the serviceability and the comfort concern of people in a building or even lead to a complete collapse. When it comes to dynamics and load-structure interaction, the inherently low damping in buildings is a key parameter that can be used to control the behavior of a structure under such dynamic loads.

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