Report No.: CCEER-93-8

Title: Vulnerability Assessment of Masonry Public Buildings in the Reno-Carson City Urban Corridor

Authors: Jamie Roybal, David Sanders, and E. 'Manos' Maragakis

Date: May 1993

Sponsoring Agency:
Nevada Division of Emergency Management
Federal Emergency Management Agency

Performing Organization:
Department of Civil Engineering/258
University of Nevada, Reno
Reno, Nevada 89557

Executive Summary:

Earthquakes can produce severe structural damage to certain types of buildings. One type of structure frequently mentioned in damage reports are masonry buildings. A masonry building is a building built using bricks, or concrete blocks, as the primary load carrying system. These buildings are vulnerable to horizontal loads resulting from earthquakes, especially if unreinforced.

By using a method known as the Rapid Screening Procedure, it is possible to get a preliminary idea if a building is seismically vulnerable. The procedure determines a structural score for the building. This Structural Score is a number that relates to the possible damage a structure would receive if an earthquake were to occur in the area.

The steps in the procedure are as follows:

  1. Locate masonry buildings either by obtaining a list from the city or by visual identification.
  2. Complete worksheet provided by the Applied Technology Council (ATC-21) and determine a Structural Score.
  3. Compare the Structural Score to a standard value of 2.0. If the building rates a score below 2.0, then a professional engineer with a background in seismic design should do a detailed analysis of the building to determine its seismic vulnerability. If the score is above 2.0, then the building is deemed safe. If, however, the score is 2.0, then it is left up to the building officials to decide if the building requires further investigation.

The cut-off value of 2.0 is a recommended value by the Applied Technology Council and ultimately should be decided by the local building officials.

The Rapid Screening Procedure was utilized to evaluate 114 reinforced and unreinforced masonry buildings in Reno, Sparks and Carson City, Nevada. Of the 114buildings, 51 require further investigation. All 51 buildings were unreinforced masonry (Summary by authors).