(a) Scope

Section A102 – Scope is amended to read as follows: A102.1 General. The provisions of this chapter shall apply to all existing buildings covered under the City of Berkeley mandatory seismic retrofit program having at least one unreinforced masonry wall as defined in this chapter. The elements regulated by this chapter shall be determined in accordance with Table A-1-A. Except as provided herein, other structural provisions of the Building Code shall apply.

A102.2 Essential and Hazardous Facilities. Buildings or structures in Occupancy Categories 1 and 2 of Table 16-K, and covered under the City of Berkeley mandatory seismic retrofit program of the Building Code, shall be strengthened in accordance with the provisions of this chapter or requirements of the Building Code for new buildings, whichever is more restrictive.

(b) DefinitionsThe definition of an unreinforced masonry bearing wall in Section A103 is amended to read as follows:

UNREINFORCED MASONRY (URM) WALL means any unreinforced masonry wall supporting its own weight when over six (6) feet in height, or any masonry wall that has all of the following characteristics:

1.    Provides the vertical support for a floor or roof.

2.    Has a total superimposed load of over 100 pounds per linear foot.

Has an area of reinforcing steel less than 50 percent by empirical methods or less than 25 percent by analysis of that required by the UBC.

(c) Symbols and Notations

New symbols are added to Section A104 - Symbols and Notations as follows: Fp = Design Seismic Forces on a part of the structure, based on working stress design methods. I = Importance Factor in accordance with Table A-1-H.

(d) Minimum Design Lateral Forces

Section A110.1 Minimum Design Lateral Forces is amended to read as follows: Buildings shall be analyzed to resist minimum lateral forces assumed to act nonconcurrently in the direction of each of the main axes of the structure in accordance with the following:

V = .20 W

(A10-1-1)

for essential facilities; or

V = .166 W

(A10-1-2)

for buildings that are not essential facilities, but have an occupant load greater than 100; or

V = .133 W

(A10-1-3)

for all other buildings.

Exception: For qualified historical buildings, alternative criteria may be approved when implementation of the provisions of this section conflicts with the objectives of preserving the historical features of the building.

For buildings more than one story in height, the total force shall be distributed over the height of the building in accordance with the procedures of Chapter 16 of the Building Code.

For the purpose of this chapter, a dynamic analysis need not be performed for those buildings with irregularities, as defined in Tables 16-L and 16-M of the Building Code, which would otherwise require such analysis. All other design and analysis requirements of these tables shall apply.

(e) Lateral Forces on Elements of Structures

Section A110.2    Lateral Forces on Elements of Structures is amended to read as follows: Parts of structures shall be analyzed and designed for lateral loads in accordance with procedures of Chapter 16 of the Building Code but not less than the following:

Fp = ICpWp

(A10-1-4)

The value of I shall be as set forth in Table A-1-H. The values of C_p shall be in accordance with the values set forth in Table A-1-J. The value of W_p shall be in accordance with the procedures of Chapter 16 of the Building Code.

Exception: 1. Unreinforced masonry walls for which height-to-thickness ratios do not exceed ratios set forth in Table A-1-B need not be analyzed for out-of-plane loading. Unreinforced masonry walls which exceed the allowable h/t ratios of Table A-1-B shall be braced according to Section A113.5. 2. Parapets complying with Section A113.6 need not be analyzed for out-of-plane loading.

(f) Chords

Section A111.4.3 Chords is amended to read as follows: An analysis for diaphragm flexure is required and chords shall be provided.

(g) Chords

A new paragraph is added to Section A113 - Detailed System Design Requirements as follows: A113.11. Chords. An analysis for diaphragm flexure is required and chords shall be provided to conform to Chapter 16 of the Building Code.

(h) Table A-1-HThe 1997 Uniform Code for Building Conservation, Appendix Chapter 1, is amended to add the following:

TABLE A-1-H – I FACTOR

Type of Occupancy	I
Essential Facility	1.5
Occupant Load Greater than 100	1.25
All Other	1.00

(i) Table A-1-JThe 1997 Uniform Code for Building Conservation, Appendix Chapter 1, is amended to add the following:

TABLE A-1-J – HORIZONTAL FORCE FACTOR, C_P, FOR PARTS OR PORTIONS OF BUILDINGS OR OTHER STRUCTURES¹

Part or Portion of Building	Direction of Force	Value of Cp
Cantilever parapet and other cantilever walls except retaining walls	Normal to flat surface	2.00
Exterior and interior ornamentation and appendages	Any Direction	1.00
Floors and roofs acting as diaphragms	In the plane of the diaphragm	0.12 2,3
Connections for exterior panels or elements	Any direction	2.00

¹ Applicable to the general procedures of Section A110.2 only.

² Floors and roofs acting as diaphragms shall be designed for a minimum force resulting from C_p of 0.12 applied to the W_p unless a greater force results from the distribution of lateral forces in accordance with Chapter 16 of the Building Code.

³ For determination of the capacity of the shear connections at the edges of wood diaphragms, the value of C_p shall be 0.2. However, the strength of the shear connections need not exceed the strength of the diaphragm as given in Table A-1-D and Table A-1-E.