SEISMIC DAMAGE TO VERTICAL BRACES IN STEEL SCHOOL BUILDINGS DUE TO THE 2011 TOHOKU EARTHQUAKE

Abstract

A reconnaissance of steel school buildings damaged by the 2011 Tohoku earthquake has been conducted by the Architectural Institute of Japan. This paper discusses the various types of seismic damage to vertical braces observed in 129 school buildings. The braces of pre-1982 buildings which were either unretrofitted or not seismically evaluated suffered more damage, compared to either pre-1982 retrofitted or post-1982 buildings. Most of the damage to connections in older buildings are caused by either old design practice, where the connection strength does not exceed the brace strength, or improper construction.