1991 AGN FEB 19 I18 - Laserfiche WebLink

Browse Search

TO: HONORABLE MAYOR and CITY COUNCIL Q FOR: Council Meeting of 19 February 1991 �± FROM: Jaime R. Aguilera, Director of Community Development 4WI For G SUBJECT: Adoption of Ordinance on Program for Seismic Retrofitting of Unreinforced Masonry Buildings. E BACKGROUND: N State Bill SB547, passed in 1986, requires local governments prepare a seismic hazard building survey and the adoption of a seismic hazard mitigation program. The Community Development Department coordinated the preparation of the survey and seismic hazard mitigation report, as previously submitted. As shown in the report, the survey identifed 31 structures (of which nine have been deleted) that are apparently of unreinforced masonry construction. The owners of the unreinforced buildings were A notified and a meeting was set up to discuss the retrofitting. The outcome of the meeting was that all the owners requested the City impose minimum requirements for the retrofit- ting, which involves the application of anchor bolts. The request of applying minimum requirements in the form of anchorbolts provides ninety to ninety-five percent of the retrofitting, since the majority of failures of unreinforced masonry buildings occur with the separation of the walls of the building from the roof. Full compliance through the use of actual retrofitting of walls and strengthening of footings provides the remaining five to ten percent of the retrofitting. STATEMENT OF THE PROBLEM: The 22 structures identified in the survey, as unreinforced masonry buildings, are a P potential hazard in the case of an earthquake that could lead to the loss of life and the destruction of property. The earthquake damage possibilites for Colton include the future earthquakes on the San O Andreas fault, San Jacinto fault, and other small events that will occur in the region. ALTERNATIVES: R With the need for compliance to the aforementioned state law, and after review by the affected property owners, staff recommends partial retrofitting through the use of anchor - bolts to hold the unreinforced masonry buildings through one of the three alternatives listed below: Agenda Report RETR02 Page 1 _ FII- uO. A..3:__7 ................ _ L