Chapter 8.43
EARTHQUAKE HAZARD ANALYSIS OF EXISTING BUILDINGS
Sections:
8.43.040 Compliance requirements.
8.43.050 Administrative provisions.
8.43.010 Purpose.
Unreinforced masonry (URN) bearing wall buildings have shown poor performance in past earthquakes, for example: 1868 Hayward, 1906 San Francisco, 1925 Santa Barbara, 1933 Long Beach, 1952 Kern County, 1971 San Fernando, 1982 Coalinga, 1987 Whittier, 1989 Loma Prieta and 1992 Humboldt County. The State of California has declared through Senate Bill 547 (Section 8875 et seq. of the Government Code) that the hazard posed by this class of building is unacceptable and that communities must identify unreinforced masonry bearing wall buildings and notify building owners that the building is considered to be one of a general type of structure that historically has exhibited little resistance to earthquake motion. The City of Sausalito provided the required notice on April 17, 1990.
It is generally accepted that the intensity of earthquakes which could reasonably be expected to occur in California would be sufficient to cause buildings with minimal seismic resistance characteristics to be seriously damaged or, perhaps, to collapse, causing serious injury or death to the occupants or passersby.
It is the intent of the City of Sausalito to gather information on the extent and nature of the seismic strengthening of unreinforced masonry bearing wall buildings which will be needed to reduce the risk of life loss or injury. This chapter provides time periods and standards under which these buildings are required to be structurally analyzed. It requires that the results of the analysis be presented to the City for review.
It is the further intent of the City of Sausalito to consider a follow-up ordinance which requires buildings found to be deficient to be strengthened in a time period and in a manner which accounts for public safety concerns and private owner interests.
The final intent of the City is to assure that seismic strengthening of any unreinforced masonry bearing wall building be completed when an owner elects to significantly remodel such building. [Ord. 1079 § 1, 1992.]
8.43.020 Scope.
The provisions of this chapter shall apply to all buildings which have been identified as having unreinforced masonry bearing walls by the survey filed with the California Seismic Safety Commission. [Ord. 1079 § 1, 1992.]
8.43.030 Definitions.
“Unreinforced masonry (URN) bearing wall” is a masonry wall in which the area of reinforcing steel is less than 25 percent of the minimum steel ratios required by the building code for reinforced masonry. [Ord. 1079 § 1, 1992.]
8.43.040 Compliance requirements.
The owner of each building within the scope of this chapter shall, upon notice by the City and within the time limits set forth in this chapter, cause a structural engineering analysis to be made of the building by an engineering design professional licensed by the State to practice as such. The owner of a building within the scope of this chapter shall comply with this requirement by submitting to the Building Official for review, within six months after mailed notice by the City, a structural analysis report which shall include the following information:
A. Whether the building meets minimum requirements of Appendix Chapter 1 of the Uniform Code for Building Conservation, 1991 Edition.
B. If the building does not meet minimum requirements, what specific deficiencies exist. Structural calculations for the existing building should be compared to the minimum requirements.
C. What modifications to the structure are necessary in order to meet minimum requirements.
D. A preliminary cost estimate of the necessary modifications.
E. An estimate of the duration of construction period required.
The structural analysis report should describe all methods employed, all tests conducted, and all measurements and calculations which provided the basis for the conclusions drawn. [Ord. 1079 § 1, 1992.]
8.43.050 Administrative provisions.
A. Notice. The Building Official shall issue a notice as provided in this section to the owner of each building within the scope of this chapter.
B. Notice – Contents. The notice shall be in writing and shall be served upon the owner either personally or by certified or registered mail, as shown on the last equalized assessment roll, and upon the person, if any, in apparent charge or control of the building. The notice shall specify that the building has been determined by the Building Official to be within the scope of this chapter and, therefore, a structural engineering analysis of the building is required.
C. Enforcement. The City will be empowered to seek an order from the court to require the study to be done. [Ord. 1079 § 1, 1992.]
8.43.060 Repair requirements.
No building for which the structural analysis consistent with this chapter is submitted to the City will be required to complete the modifications needed to meet minimum requirements except that unreinforced masonry wall buildings to which additions, alterations or repairs are made, the cost of which exceeds 50 percent of the replacement value, shall be made to comply with the provisions of Appendix Chapter 1 of the Uniform Code for Building Conservation, 1991 Edition, published by the International Conference of Building Officials. [Ord. 1079 § 1, 1992.]