Seismic Regulations Versus Modern Architectural and Urban Configurations

Abstract

Every time an earthquake affects a contemporary city, numerous lessons arise regarding the performance of modern buildings. However, lessons included in international post-earthquake reconnaissance reports regarding the influence of architectural features on building seismic performance barely reach either architectural and city planning practice, or decisions taken by city officials and politicians that continue including in the design of urban zoning regulations (UZR) some modern building configurations categorized in seismic codes as “irregular.” Irregularities, in terms of building configuration, mean that the structural design and analysis require the application of special considerations, as well as rigorous official controls on the construction site for the appropriate application of seismic detailing requirements. The majority of UZR in contemporary cities encourages, and in some cases enforces, the use of configurations that have been long recognized by earthquake engineering as seismically vulnerable. It is not surprising that when an earthquake affects a contemporary city, the buildings worst hit are precisely those with modern architectural configurations that affect the vulnerability and resilience of cities in seismic zones and are common all around the world. Earthquake experiences have taught that the application of structural engineering oriented building codes is not sufficient for reducing the seismic vulnerability of contemporary cities. The problem has to be untangled with a holistic approach where structural engineers, architects, urban planners, local authorities and the local community participate, not only in reducing existing vulnerability but avoiding the construction of new seismic risk in the future. In order to study the discrepancy between urban zoning regulations and seismic codes with regard to vulnerable modern building configurations and the causes of the international dissemination of architectural and urban planning concepts that generate vulnerability in contemporary cities, historic research was developed. This paper presents a brief summary of this study [1].