Yuba County Municipal Code Ch. 10.50 Repair and Reconstruction Ordinance

(Formerly Chapter 10.05, Section 10.05.150; Prior Ord. No. 1483; 1501)

It is the intent of the Board of Supervisors in adopting this Chapter to provide additional measures regarding the repair of buildings or structures damaged as a result of natural disaster. These additions and amendments to Chapter 34 of the California Building Code (CBC) are intended to reduce the amount of time for repairs thus minimizing the amount of time owners and/or occupants are displaced from their buildings.

(Ord. No. 1528)

These additions and amendments are necessary to further safeguard the public health, safety and general welfare because of local geological conditions that present a danger to the County's existing buildings and structures. Pursuant to California Health and Safety Code § 17958.7, these express findings are either on file or will be filed with the California Building Standards Commission prior to the effective date of the ordinance from which this chapter derives.

(Ord. No. 1528)

In the event an amendment to the California Building Standards Code results in differences between these building standards and the California Building Standards Code, the text of these building standards shall govern.

(Ord. No. 1528)

For the purposes of this Chapter, the following definition applies and is hereby added to Section 3402, Definitions, of the California Building Code:

A. SUBSTANTIAL STRUCTURAL DAMAGE. A condition where:

1. In any story, the vertical elements of the lateral-force resisting-system have suffered damage such that the lateral load-carrying capacity of the structure in any direction has been reduced by more than 20 percent from its pre-damaged condition, or:

2. The capacity of any vertical gravity load-carrying component, or any group of such components that supports more than 30 percent of the total area of the structures floor(s) and roof(s) has been reduced more than 20 percent from its pre-damaged condition, and the remaining capacity of such affected elements with respect to all dead and live loads is less than 75 percent of that that required by the building code for new buildings of similar structure, purpose and location.

(Ord. No. 1528)

The following Sections are hereby added to Section 3405, Repairs, in Volume 2 of the California Building Code:

A. 3405.6 Seismic Evaluation and Design. Existing buildings, structure and their components shall be based on the following criteria:

1. California Building Code

2. American Society of Civil Engineers (ASCE) 31, Seismic Evaluation of Existing Buildings

3. American Society of Civil Engineers (ASCE) 41, Seismic Rehabilitation of Existing Buildings

4. Appendix A of the International Existing Building Code (IEBC)

B. 3405.6.1 Seismic Forces. When seismic forces are required to meet the levels prescribed by the Building Code, they shall be one of the following:

1. 100 percent of the values as prescribed in the Building Code. The R factor used for analysis in accordance with Chapter 16 of the Building Code shall be the R factor specified for structural systems classified as "Ordinary" unless it can be demonstrated that the structural system satisfies the proportioning and detailing requirements for systems classified as "Intermediate" or "Special".

2. Where ASCE 41 is used, the corresponding BSE-1 and BSE-2 Earthquake Hazard Levels performance levels as shown in Table 3405.6 shall be used.

TABLE 3405.6

ASCE 41 and ASCE 31 PERFORMANCE LEVELS

C. 3405.6.2 Reduced CBC level seismic forces. When seismic forces are permitted to meet reduced building code levels, they shall be one of the following:

1. 75 percent of the forces prescribed in the building code. The R factor used for analysis in accordance with Chapter 16 of the building code shall be the R factor as specified in Section 3405.6.1 item 1.

2. In accordance with the applicable Chapters in Appendix A of the IEBC, as specified in items a through e below. Structures or portions of structures that comply with the applicable requirements in IEBC Appendix A shall be deemed to comply with the requirements for reduced building code force levels.

a. The seismic evaluation and design of unreinforced masonry bearing wall buildings in Occupancy Category I or II are permitted to be based on the procedures specified in IEBC Appendix Chapter Al.

b. Seismic evaluation and design of the wall anchorage system in reinforced concrete and reinforced masonry wall buildings with flexible diaphragms in Occupancy Category I or II are permitted to be based on the procedures specified in IEBC Appendix Chapter A2.

c. Seismic evaluation and design of cripple walls and sill plate anchorage in residential buildings of light-frame wood construction in Occupancy Category I or II are permitted to be based on the procedures specified in IEBC Appendix Chapter A3.

d. Seismic evaluation and design of soft, weak, or open-front wall conditions in existing multi-unit residential buildings of light-frame wood construction in Occupancy Category I or II are permitted to be based on the procedures specified in IEBC Appendix Chapter A4.

e. Seismic evaluation and design of existing concrete buildings and concrete with masonry infill buildings in all Occupancy Categories are permitted to be based on the procedures specified in IEBC Appendix Chapter A5.

3. Where ASCE 31 is used, the performance levels as shown in Table 3405.6

4. Where ASCE 41 is used, the performance level as shown in Table 3405.6. Additionally the design spectral response acceleration parameters Sxs and Sx1 shall not be taken less than 75 percent of the respective design spectral response acceleration parameters SDS and SD1 defined by the IBC and its reference standards.

D. 3405.6.3 Referenced Standards.

(Ord. No. 1528)

If any Section, Subsection, sentence, clause, or phrase of this Chapter is for any reason held to be invalid, unlawful, or unconstitutional, such invalidity or unconstitutionality shall not affect the validity, lawfulness, or constitutionality of any or all other portions of this Chapter.

(Ord. No. 1528)