City of Rancho Cucamonga, CA Chapter 15.42 EARTHQUAKE HAZARD REDUCTION IN UNREINFORCED MASONRY BUILDINGS

§ 15.42.010 Purpose.

A. The purpose of this chapter is to promote public safety and welfare by reducing the risk of death or injury that may result from the effects of earthquakes on unreinforced masonry bearing wall buildings constructed before 1946. Such buildings have been widely recognized as sustaining life-hazardous damage as a result of partial or complete collapse during past moderate to strong earthquakes.

B. The provisions of this chapter are minimum standards for structural seismic resistance established primarily to reduce the risk of life loss or injury and will not necessarily prevent loss of life or injury or prevent earthquake damage to an existing building which complies with these standards. This chapter shall not require existing electrical, plumbing, mechanical or fire safety systems to be altered, unless they constitute a hazard to life or property.

C. This chapter provides procedures and standards for identification and classification of unreinforced masonry bearing wall buildings based on their present use. Priorities, time periods and standards are also established under which these buildings are required to be structurally analyzed and anchored. Where the analysis determines deficiencies, this chapter requires the building to be strengthened or demolished.

D. However, the provisions of this chapter do not preclude the preservation of historic buildings. In fact, preservation of historic buildings is encouraged through the permissive use of applicable portions of the State Historical Building Code (SHBC), established under Part 8, Title 24 of the California Administrative Code. In addition, the city will pursue incentives to assist property owners in obtaining aid offered by federal, state and local agencies. These incentives are further elaborated on in section 15.42.070.F.

(Code 1980, § 15.42.010; Ord. No. 417 § 4, 1990)

§ 15.42.020 Scope.

A. The provisions of this chapter shall apply to all buildings constructed or under construction prior to 1946, or for which a building permit was issued prior to 1946, which on the effective date of the ordinance codified in this chapter have unreinforced bearing walls as defined in this chapter.

B. Exception. This chapter shall not apply to detached one- or two-family dwellings and detached apartment houses containing less than five dwelling units and used solely for residential purposes.

(Code 1980, § 15.42.020; Ord. No. 417 § 4, 1990)

§ 15.42.030 Definitions.

For purposes of this chapter, the applicable definitions in sections 2302 and 2312 of the Uniform Building Code, 1988 Edition (UBC, 1988 Edition) and the following shall apply:

"Crosswalls"

mean interior walls of masonry or wood frame construction with surface finish of wood lath and plaster, minimum one-half inch thick gypsum wallboard or solid horizontal wood sheathing. In order to be considered as a crosswall within the intent of this chapter, the crosswalls shall be spaced at not more than 40 feet apart in each story, and shall be full story height with a minimum length of one and one-half times the story height.

"High risk building"

means any building having an occupant load of 100 occupants or more as determined by Section 3302, Uniform Building Code, 1988 Edition. Exception: Buildings meeting either or both of the following criteria need not be classified as high risk buildings:

A. Any building having exterior walls braced with crosswalls as defined in subsection A of this section;

B. Any building used for its intended purpose, as determined by the building official, for less than 20 hours per week.

"Historic building"

means any building designated as an historic building by an appropriate federal or state agency, or as landmark by the city council of the city, and any building on a local, state or national inventory of historic resources.

"Low risk building"

means any building having an occupant load of less than 20 occupants, as determined by Section 3302, Uniform Building Code, 1988 Edition.

"Medium risk building"

means any building having an occupant load of more than 20, but less than 100, as determined by Section 3302, Uniform Building Code, 1988 Edition.

"Unreinforced masonry bearing wall"

means a masonry wall having all of the following characteristics:

A. Providing vertical support for a floor or roof;

B. Having a total superimposed load of over 100 pounds per linear foot;

C. Having reinforcing steel less than 50 percent of that required by Section 2407(h)4B, Uniform Building Code, 1988 Edition.

(Code 1980, § 15.42.030; Ord. No. 417 § 4, 1990; Ord. No. 870 (Recodification), 2014)

§ 15.42.040 Rating classification.

A. Buildings subject to this chapter shall be classified by the building official as high risk, medium risk, or low risk buildings as defined in section 15.42.030. The total occupant load of the entire building as determined by Section 3302, Uniform Building Code, 1988 Edition, shall be used to determine the rating classification.

B. Exceptions.

1. For the purpose of this chapter, portions of buildings constructed to act independently when resisting seismic forces may be placed in separate rating classifications;

2. The building official may allow the use of a verified occupancy load rather than the occupancy load specified in Section 3302, Uniform Building Code, 1988 Edition in determining the rating classification.

(Code 1980, § 15.42.040; Ord. No. 417 § 4, 1990)

§ 15.42.050 General requirements.

The owner of each building within the scope of this chapter shall cause a structural analysis to be made of the building by a civil or structural engineer or architect licensed by the state; and if the building does not meet the minimum earthquake standards specified in this chapter, the owner shall cause it to be structurally altered to conform to such standards; or cause the building to be demolished.

A. Service of order. The city shall have up to 270 days in which to serve the order as outlined in section 15.42.060.

B. Compliance. Upon service of the order, the owner of a building, identified within the scope of this chapter, shall comply with one of the following requirements:

1. Within 270 days after the service of the order, a structural analysis shall be submitted to the building official for review. Such analysis shall demonstrate that the building meets the minimum requirements of this chapter; or

2. Within 270 days after the service of the order, the structural analysis and plans for the proposed structural alterations of the building necessary to comply with the minimum requirements of this chapter shall be submitted; or

3. Within 270 days after the service of the order, a letter of intention to demolish the building shall be submitted. Any proposed demolition of a historic building, as defined in section 15.42.030, must first undergo landmark application review to determine the historical merit of the structure. In addition to review for landmark status, the historic preservation commission shall determine the need for and required contents of a feasibility study to examine the possible alternatives to demolition which may include a cost/benefit analysis, reconstruction alternatives, relocation feasibility or other similar analysis determined necessary by the commission. The study shall be completed by a city-hired consultant, but financed by the applicant, and shall be reviewed by the community development director or designee and reported to the historic preservation commission.

C. Building permit. After plans or letter of intention to demolish are submitted and approved by the building official, the owner shall obtain a building permit, and commence and complete the required construction or demolition within the time limits set forth in this subsection. These time limits shall begin to run from the date the order is served in accordance with section 15.42.060(A) and (B).

1. The property owner shall have one year from the date the order is served to obtain a building permit to complete structural alterations or building demolition.

2. The property owner shall have a total of three years from date the order is served to complete construction of any structural alterations.

Exception. The building official may allow an extension of time, for obtaining a building permit or demonstrating compliance with this chapter as set forth in section 15.42.050, of up to an additional one year, if it is demonstrated that there is no immediate hazard to life safety and that there will be no adverse impact upon adjacent properties. Any further request for extensions of time shall be accomplished in the manner set forth in section 15.42.060(C).

(Code 1980, § 15.42.050; Ord. No. 417 § 4, 1990; Ord. No. 870 (Recodification), 2014)

§ 15.42.060 Administration.

A. Service of order. The building official shall issue an order, as provided in subsection B of this section, to the owner of each building within the scope of this chapter. Service of the order shall not occur until such time that the planning director and building official shall determine that the incentive programs, referenced in section 15.42.070(F) are in place and operational, but shall be no longer than 270 days from the effective date of the ordinance codified in this chapter.

B. Contents of order. The order shall be in writing and shall be served either personally or by certified or registered mail upon the owner as shown on the last equalized assessment, and upon the person, if any, in apparent charge or control of the building. The order shall specify that the building has been determined by the building official to be within the scope of this chapter and, therefor, is required to meet the minimum seismic standards of this chapter. The order shall specify the rating classification of the building and shall be accompanied by an informational pamphlet, as referenced in section 15.42.070(F), which shall also include a copy of section 15.42.050 and shall include alternatives and time limits for compliance.

C. Appeal order. The owner or person in charge or control of the building may appeal the building official's determination that the building is within the scope of this chapter to the city council. Such appeal shall be filed with the building official within 30 days from the service date of the order of the building official. Any such appeal shall be scheduled for hearing before the city council, not later than 60 days after the date that the appeal is filed. Such appeal shall be made in writing upon appropriate forms provided therefor by the building official, and the grounds for appeal and the justification thereof shall be stated clearly and concisely. Each appeal shall be accompanied by a filing fee as determined by city council resolution.

D. Recordation. At the time that the building official serves the order, the building official shall file with the office of the county recorder a certificate stating that the subject building is within the scope of chapter 15.42. The certificate shall also state that the owner thereof has been ordered to structurally analyze the building and to structurally alter it or demolish it where compliance with chapter 15.42 is not exhibited. If the building is either demolished, found not to be within the scope of this chapter, or is found to be structurally capable of resisting seismic forces required by this chapter as a result of structural alterations or an analysis, the building official shall file with the office of the county recorder a certificate terminating the status of the subject building as being classified within the scope of chapter 15.42.

E. Enforcement. If the owner or other person in charge or control of the subject building fails to comply with any order issued by the building official pursuant to this chapter within any of the time limits set forth in section 15.42.050, the building official shall order that the entire building be vacated and that the building remain vacated until such order has been complied with. If compliance with such order to vacate has not been accomplished within 90 days after the date the building has been ordered vacated or such additional time as may have been granted by the city council, the building official may order its demolition or abatement in accordance with the provisions of the procedure set forth in the Uniform Code for Abatement of Dangerous Buildings as adopted by chapter 15.28.

(Code 1980, § 15.42.060; Ord. No. 417 § 4, 1990; Ord. No. 870 (Recodification), 2014)

§ 15.42.070 Historic buildings.

A. Historic preservation review. Any proposal for the structural alteration or demolition of an historic building, as defined in this chapter, shall require review by the historic preservation commission prior to issuance of any building or demolition permits.

B. Scope. The commission shall review all plans, proposed structural revisions and demolitions for preservation of historic character, quality of design and aesthetic considerations, review fee waiver requests and demolition feasibility studies and make recommendations to the city council regarding potential designations.

C. Additional information. Additional architectural elevations and details may be requested in order to provide clarification in review of the proposed revisions.

D. General. The standards and procedures established by this chapter shall apply in all respects to a historic building, except that as a means to preserve original architectural elements and facilitate restoration, a historic building may, in addition, comply with the special provisions set forth in this section.

E. Unburned clay masonry or adobe. Existing or re-erected walls of adobe construction shall conform to the following:

1. Unreinforced adobe masonry walls shall not exceed a height or length to thickness ratio of five, for exterior bearing walls and must be provided with a reinforced bond beam at the top, interconnecting all walls. The bond beam shall have a minimum depth of six inches. The bond beam may have a width equal to the width of the wall less eight inches, provided the resulting width is not less than eight inches. Minimum wall thickness shall be 18 inches for exterior bearing walls and ten inches for adobe partitions.

2. Foundation footings shall be reinforced concrete under newly reconstructed walls and shall be not less than 50 percent wider than the wall above, soil conditions permitting.

3. New or existing unstabilized brick and adobe brick masonry shall have an average compressive strength of 225 pounds per square inch when tested in accordance with ASTM designation C67. One sample out of five may have a compressive strength of not less than 188 pounds per square inch. Unstabilized brick may be used where existing bricks are unstabilized and where the building is not susceptible to flooding conditions or direct exposure. Adobe may be allowed a maximum value of three pounds per square inch for shear with no increase for lateral forces.

4. Mortar may be of the same soil composition and stabilization as the brick in lieu of cement mortar.

5. Nominal tension stresses due to seismic forces normal to the wall may be neglected if the wall meets thicknesses requirements and shear values allowed by this subsection.

6. Allowable stresses for archaic materials not specified in the Uniform Building Code, 1988 Edition, shall be based on substantiating research data or engineering judgment subject to the building official's approval.

7. Alternative materials, design or methods of construction may be considered as set forth in Section 105 of the Uniform Building Code, 1988 Edition. In addition, when a request for an alternative proposed design, material or method of construction is being considered, the building official may file written request for opinion to the state historical building code advisory board for its consideration, advice or findings in accordance with the SHBC.

F. Incentives. In order to encourage the preservation of historic structures, the following incentive programs are to be explored and information made available to property owners with buildings subject to the provisions of this chapter. This list does not preclude the use of alternatives not identified here.

1. The planning division shall develop an informational pamphlet, which shall be sent to property owners of buildings identified subject to the provisions of this chapter, which shall be mailed concurrently with the order specified in section 15.42.060(A). The pamphlet shall explain the basic provisions of SB 547 and this chapter and shall outline the various options and incentives available to property owners, including financial assistance and design consultation.

2. The city shall provide funds which may be used toward design consultation for owners of historic structures. The city has funds which may be available for this use through the community development block grant (CDBG) program and through the historic preservation section of the planning division budget. Within six months from the effective date of the ordinance codified in this chapter, program guidelines shall be developed for use of these funds.

3. As a majority of the historic unreinforced masonry buildings are within the redevelopment project area, available funds may be used toward historic rehabilitation.

4. The city shall investigate the possibility for setting up a local loan program for seismic rehabilitation as referenced in the Health and Safety Code §§ 55000 through 55009. An analysis and determination of the feasibility for setting up the program shall be made within six months from the date of enaction of the ordinance codified in this chapter. If it is determined that a program is to be developed, then the criteria, guidelines and enabling legislation shall be developed within 270 days from the effective date of the ordinance codified in this chapter.

5. Upon request, the city shall provide information about the Mills Act to owners of historic buildings. The Mills Act allows property tax benefits in exchange for preservation of a building.

6. The historic preservation commission may recommend to the city council waiving applicable building permit, plan check, design review, land use and landmark alteration fees for historic structures which are designated local landmarks, or for those structures determined to be significant through the landmark review process. In review of the request, the historic preservation commission shall give consideration to the architectural and historical merit of the proposed seismic retrofit and/or structural alteration.

7. Additional financing may be available through state and federal agencies and may include:

a. Tax credits for rehabilitation which are available under the 1986 Tax Act. To be eligible for the higher 20 percent historic building tax credits, the construction documents must be approved by the state historic preservation office and National Park Service.

b. Funding for seismic retrofit may also be available through the Small Business Administration (SBA), and may be used for engineering, planning, permits and construction costs. Borrowers shall include businesses that meet the agency's size standard and eligibility requirements.

(Code 1980, § 15.42.070; Ord. No. 417 § 4, 1990; Ord. No. 870 (Recodification), 2014)

§ 15.42.080 Analysis and design.

A. General. Every structure within the scope of this chapter shall be analyzed and constructed to resist minimum total lateral seismic forced assumed to act nonconcurrently in the direction of each of the main axes of the structure in accordance with the following equation:

V = ZIKCSW (Formula III-1)

The value of KCS need not exceed the values set forth in Table Number Ill-A (Exhibit A attached to the ordinance codified in this chapter and located at the end of this chapter) based on the seismic zone as determined by the building code. The value of Z shall be the value specified in Table Number Ill-B (Exhibit A). The I factor shall be as specified in Table Number Ill-C (Exhibit A). The value of W shall be as set forth in the Uniform Building Code, 1988 Edition.

B. Lateral forces on elements of structures. Parts or portions of structures shall be analyzed and designed for lateral loads in accordance with subsection A of this section and Chapter 23, Uniform Building Code, 1988 Edition, but not less than the value from the following equation:

Fp = ZICp SWp (Formula III-2)

For the provisions of this subsection, the product of IS need not exceed the values as set forth in Table Number III-D (Exhibit A). The value of Cp need not exceed the values as set forth in Table Number III-M (Exhibit G). The value of Wp shall be as set forth in the Uniform Building Code, 1988 Edition.

Exception. Unreinforced masonry walls may be analyzed in accordance with section 15.42.090.

C. Anchorage and interconnection. Anchorage and interconnection of all parts, portions and elements of the structure shall be analyzed and designed for lateral forces in accordance with the Uniform Building Code, 1988 Edition and the equation:

Fp = ZICp 2)

as modified by Table Number III-D (Exhibit A). Minimum anchorage of masonry walls to each floor or roof shall resist a minimum force of 200 pounds per linear foot acting normal to the wall at the level of the floor or roof.

D. Level of required repair. Alterations and repairs required to meet the provisions of this chapter shall comply with all other applicable requirements of the Uniform Building Code, 1988 Edition, unless specifically provided for in this chapter.

E. Required analysis. Except as modified in this subsection, the analysis and design relating to the structural alteration of existing structures within the scope of this chapter shall be in accordance with the analysis specified in Chapter 23, Uniform Building Code, 1988 Edition.

1. Continuous stress path. A complete, continuous stress path from every part or portion of the structure to the ground shall be provided for the required horizontal forces.

2. Positive connections. All parts, portions or elements of the structure shall be interconnected by positive means.

F. Analysis procedure. Stresses in materials and existing construction utilized to transfer seismic forces from the ground to parts or portions of the structure shall conform to those permitted by the Uniform Building Code, 1988 Edition, and those materials and types of construction specified in section 15.42.090. Materials and connectors used for interconnection of parts and portions of the structure shall conform to the Uniform Building Code, 1988 Edition.

Except as modified in this chapter, unreinforced masonry walls shall be analyzed as specified in Sections 2416, 2418 and 2419 of the Uniform Building Code, 1988 Edition, to withstand all vertical loads as specified in Chapter 23, Uniform Building Code, 1988 Edition, in addition to the seismic forces required by this chapter.

No allowable tension stress will be permitted in unreinforced masonry walls. Walls not capable of resisting the required design forces specified in this chapter shall be strengthened or shall be removed or replaced.

Exceptions.

1. Unreinforced masonry walls may be analyzed in accordance with section 15.42.090.

2. Unreinforced masonry walls which carry no design loads other than its own weight may be considered as veneer if they are adequately anchored to new supporting elements.

3. The 50 percent increase in the seismic force factor for shear walls as specified in Table Number 24-H of the Uniform Building Code, 1988 Edition, may be omitted in the computation of seismic loads to existing shear walls.

G. Combination of vertical and seismic forces. All new materials introduced into the structure to meet the requirements of this section which are subjected to combined vertical and horizontal forces, shall comply with Section 104(b) of the Uniform Building Code, 1988 Edition, except as follows:

1. Stresses in existing lateral force resisting elements due to a combination of dead loads, plus live loads, plus seismic loads may be increased 100 percent over allowable working stresses specified in the Uniform Building Code, 1988 Edition, however, shall not exceed those permitted by section 15.42.090;

2. Stresses in members due only to seismic and dead loads shall not exceed the values permitted by Section 2303(d) of the Uniform Building Code, 1988 Edition;

3. Calculated tensile fiber stress may be reduced by the full direct stress due to vertical dead loads.

(Code 1980, § 15.42.080; Ord. No. 417 § 4, 1990; Ord. No. 870 (Recodification), 2014)

§ 15.42.090 Materials of construction.

All materials permitted by the Uniform Building Code, 1988 Edition, including their appropriate allowable stresses and existing configurations of materials specified in this chapter may be utilized to meet the requirements of this chapter.

A. Existing materials. In addition to the materials permitted by the Uniform Building Code, existing configurations of materials specified in this section may be utilized as outlined in this subsection.

1. Unreinforced masonry walls.

a. Unreinforced masonry walls analyzed in accordance with this section may provide vertical support for roof and floor construction and resistance to lateral loads. The bonding of such walls shall be specified in Section 2312(b) of the Uniform Building Code, 1988 Edition.

b. Tension stresses due to seismic forces normal to the wall may be neglected if the wall does not exceed the height or length to thickness ratio and the inplane shear stresses due to seismic loads as set forth in Table Number Ill-F (contained in Exhibit G).

c. If the wall height-thickness ratio exceeds the specified limits, the wall may be supported by vertical bracing members designed in accordance with section 15.42.080. The deflection of such bracing member at design loads shall not exceed one-tenth of the wall thickness.

Exception. The wall may be supported by flexible vertical bracing members designed in accordance with section 15.42.080(B) if the deflection at design loads is not less than one-quarter or more than one-third of the wall thickness.

All vertical bracing members shall be attached to floor and roof construction for their design loads independently of required wall anchors. Horizontal spacing of vertical bracing members shall not exceed one-half the unsupported height or ten feet.

d. The wall height may be measured vertically to bracing elements other than a floor or roof. Spacing of the bracing elements and wall anchors shall not exceed six feet. Bracing elements shall be detailed to minimize the horizontal displacement of the wall by components of vertical displacement of the floor or roof.

e. All unreinforced masonry walls utilized to carry vertical loads and seismic forces parallel and perpendicular to the wall plane shall be tested as specified in this subsection.

i. All masonry quality shall equal or exceed the minimum standards established in this chapter or shall be removed and replaced by new materials. Alternate methods of testing may be approved by the building official. The quality of mortar in all masonry walls shall be determined by performing inplane shear tests or by testing eight-inch diameter cores. Alternative methods of testing may be approved by the building official. Nothing shall prevent pointing with mortar of all the masonry wall joints before the tests are first made. Prior to any pointing the mortar joints must be raked and cleaned to remove loose and deteriorated mortar. Mortar for pointing shall be Type S or N, except masonry cements shall not be used. All preparation and mortar pointing shall be done under the continuous inspection of a registered deputy building inspector. At the conclusion of the inspection, the inspector shall submit a written report to the licensed engineer or architect responsible for the seismic analysis of the building setting forth the result of the work inspected. Such report shall be submitted to the building official for approval as part of the structural analysis. All testing shall be performed in accordance with the requirements specified in this subsection by a testing agency approved by the building official. An accurate record of all such tests and their location in the building shall be submitted to the building official for approval as part of the structural analysis.

ii. The minimum number of tests shall be two per wall or line of wall elements resisting a common force, or one per 1,500 square feet of wall surface, with a minimum of eight tests in any case. The exact test or core location shall be determined at the building site by the licensed engineer or architect responsible for the seismic analysis of the building, subject to approval of the building official.

iii. The bed joints of the outer wythe of the masonry shall be tested in shear by laterally displacing a single brick relative to the adjacent bricks in that wythe. The opposite head joint of the brick to be tested shall be removed and cleaned prior to testing. The minimum quality mortar in 80 percent of the shear tests shall not be less than the total of 30 pounds per square inch plus the axial stress in the wall at the point of the test. The shear stress shall be based on the gross area of both bed joints and shall be that at which movement of the brick is first observed.

iv. A minimum number of mortar test specimens equal to the number of required cores shall be prepared from the cores and tested as specified in this chapter. The mortar joint of the outer wythe of the masonry core shall be tested in shear by placing the circular core section in a compression testing machine with the mortar bed joint rotated 15 degrees from the axis of the applied load. The mortar joint tested in shear shall have an average ultimate stress of 20 pounds per square inch based on the gross area. The average shall be obtained from the total number of cores made. If test specimens cannot be made from cores taken then the shear value shall be reported as zero.

2. Existing material configurations, including wood shear walls utilized in the configurations may be used as part of the lateral load resisting system, provided that the stresses in these materials do not exceed the values shown in Table Number III-G (Exhibit C).

B. Strengthening of existing materials. New materials, including wood shear walls, may be utilized to strengthen portions of the existing seismic resisting system in the described configurations, provided that the stresses do not exceed the values shown in Table Number Ill-H (Exhibit D).

C. Alternate materials. Alternate materials, designs and methods of construction may be approved by the building official in accordance with the provisions of Section 105, Uniform Building Code, 1988 Edition.

D. Testing of shear bolts. One-fourth of all new shear bolts and dowels embedded in unreinforced masonry walls shall be tested by a registered deputy building inspector using a torque calibrated wrench to the following minimum torques:

½″ diameter bolts or dowels, 40 foot-pounds

5/8″ diameter bolts or dowels, 50 foot-pounds

¾″ diameter bolts or dowels, 60 foot-pounds

No bolts exceeding three-quarter inch shall be used. All nuts shall be installed over malleable iron or plate washers when bearing on wood and heavy cut washers when bearing on steel.

E. (Reserved)

F. (Reserved)

G. Determination of allowable stresses for design methods based on test results. Allowable stresses for design methods based on test results shall be as follows:

1. Design seismic inplane shear stresses shall be substantiated by tests performed as specified in section 15.42.090. Design stresses shall be related to test results obtained in accordance with Table Number Ill-I (Exhibit E). Intermediate values between three and ten pounds per square inch may be interpolated.

2. Compression stresses for unreinforced masonry having a minimum design shear value of three pounds per square inch shall not exceed 100 pounds per square inch.

3. Design tension values for unreinforced masonry shall not be permitted.

H. Anchor tests.

1. Five percent of the existing rod anchors utilized as all or part of the required wall anchors shall be tested in pullout by an approved testing laboratory. The minimum number tested shall be four per floor, with two tests at walls with joists parallel to the wall. The test apparatus shall be supported on the masonry wall at a minimum distance of the wall thickness from the anchor tested. The rod anchor shall be given a preload of 300 pounds prior to establishing a datum for recording elongation. The tension test load reported shall be recorded at one-eighth inch relative movement of the anchor and the adjacent masonry surface. Results of all tests shall be reported. The report shall include the test results as related to the wall thickness and joint orientation. The allowable resistance value of the existing anchors shall be 40 percent of the average of those tested anchors having the same wall thickness and joist orientation.

2. Qualification tests for devices used for wall anchorage shall be tested with the entire tension load carried on the enlarged head at the exterior face of the wall. Bond on the part of the device between the enlarged head and the interior wall face shall be eliminated for the qualification tests. The resistance value assigned the device shall be 20 percent of the average of the ultimate loads.

(Code 1980, § 15.42.090; Ord. No. 417 § 4, 1990; Ord. No. 870 (Recodification), 2014)

§ 15.42.100 Information required on plans.

A. General. In addition to the seismic analysis required elsewhere in this chapter, the licensed engineer or architect responsible for the seismic analysis of the building shall determine and include the information required by this section on the approved plans as follows.

1. All unreinforced masonry walls shall be anchored at the roof level by tension bolts through the wall as specified in Table Number Ill-H (Exhibit D), or by approved equivalent at a maximum anchor spacing of six feet. All unreinforced masonry walls shall be anchored at all floors with tension bolts through the wall or by existing rod anchors at a maximum anchor spacing of six feet. All existing rod anchors shall be secured to the joists to develop the required forces. The building official may require testing to verify the adequacy of the embedded ends of existing rod anchors. Tests when required shall conform to section 15.42.090(H). When access to the exterior face of the masonry wall is prevented by proximity of an existing building, wall anchors conforming to items five and six in Table Number Ill-H (Exhibit D) may be used. Alternative devices to be used in lieu of tension bolts for masonry wall anchorage shall be tested as specified in section 15.42.090(I);

2. Diaphragm chord stresses of horizontal diaphragms shall be developed in existing materials or by addition of new materials;

3. Where trusses and beams other than rafters or joists are supported on masonry, ledgers or columns shall be installed to support vertical loads;

4. Parapets and exterior wall appendages not capable of resisting the forces specified in this chapter shall be removed, stabilized or braced to ensure that the parapets and appendages remain in their original position;

5. All deteriorated mortar joints in unreinforced masonry walls shall be pointed with Type S or N mortar (masonry cements shall not be used). Prior to any pointing, the wall surface must be raked and cleaned to remove loose and deteriorated mortar. All preparation and pointing shall be done under the continuous inspection of a registered deputy building inspector certified to inspect masonry or concrete. At the conclusion of the project, the inspector shall submit a written report to the building official setting forth the portion of work inspected;

6. Repair details shall be provided for any cracked or damaged unreinforced masonry wall required to resist forces specified in this chapter;

7. The type and dimensions of existing walls and the size and spacing of existing floor and roof members;

8. The extent and type of existing wall anchorage to floors and roof;

9. Accurately dimensioned floor plans and masonry wall elevations showing dimensioned openings, piers, wall thickness and heights;

10. The location of cracks or damaged portions of unreinforced masonry walls requiring repairs;

11. The type of interior wall and ceiling surfaces and if reinstalling or anchoring of ceiling plaster is necessary;

12. The general condition of the mortar joints and if the joints need pointing.

(Code 1980, § 15.42.100; Ord. No. 417 § 4, 1990)

§ 15.42.110 Tables.

Table III-A HORIZONTAL FORCE FACTORS BASED ON OCCUPANT LOAD
Occupant Load	KCS
Building with an occupant load greater than 100	0.133
All others	0.100

Table III-B Z FACTOR
Seismic Zone	Factor
Zone 4	1

Table III-C I FACTOR
Occupancy	Factor
All buildings (high, medium and low risk)	1.0

Table III-D HORIZONTAL FORCE FACTORS "IS" FOR PARTS OR PORTIONS OF STRUCTURES
Rating Classification	IS
High risk building medium and low risk buildings	1.00 .75

Table III-E REGULATED ELEMENTS
Building Element	Seismic Zone 4
Walls: h/t Ratio Tension bolts (bending) In-plane shear Parapets Floors and Roofs: Diaphragm stress and diaphragm chords	x x x x x

Table III-F ALLOWABLE VALUE OF HEIGHT-THICKNESS RATIO OF UNREINFORCED MASONRY WALLS WITH MINIMUM QUALITY MORTAR
	Buildings with Crosswalks as defined by section 15.42.030	All Other Buildings
Walls of one story buildings	16	13
First story wall of multi-story building	16	15
Walls in top story of multi-story buildings	14	9
All other walls	16	13

1	Minimum quality mortar shall be determined by laboratory testing in accordance with section 15.42.090.(A)(1)(e).
2	Table III-G is not applicable to buildings of rating classification I. Walls of buildings within rating classification I shall be analyzed in accordance with section 15.42.080(F).

Table III-G VALUES FOR EXISTING MATERIALS
New Materials or Configuration of Materials 1	Allowable Values
1. Horizontal diaphragms
a. Roofs with straight sheathing and roofing applied directly to the sheathing.	100 lbs./ft. for seismic shear.
b. Roofs with diagonal sheathing and roofing applied directly to the sheathing.	400 lbs./ft. for seismic shear.
c. Floors with straight tongue and groove sheathing.	150 lbs./ft. for seismic shear.
d. Floors with straight sheathing and finished wood flooring.	300 lbs./ft. for seismic shear.
e. Floors with diagonal sheathing and finished wood flooring.	450 lbs./ft. for seismic shear.
f. Floors or roofs with straight sheathing and plaster applied to the joist or rafters. 2	Add 50 lbs./ft. to the allowable values for items 1.a. & c.
2. Shear walls
a. Wood stud walls with lath and plaster.	100 lbs./ft. each side for seismic shear.
3. Plain concrete footings	f = 1500 psi unless otherwise shown by tests.
4. Douglas Fir Wood	Allowable stress same as #1 D.F. 3
5. Reinforcing Steel	ft = 18,000 lbs./sq. ft. maximum 3
6. Structural Steel	ft = 20,000 lbs./sq. ft. maximum 3

1	Material must be sound and in good condition.
2	The wood lath and plaster must be reattached to existing joists or rafters in a manner approved by the building official.
3	Stresses given may be increased for combinations of loads as specified in section 15.42.080(G)(2).

Table III-H ALLOWABLE VALUES OF NEW MATERIALS USED IN CONJUNCTION WITH EXISTING CONSTRUCTION
	New Materials or Configuration of Materials	Allowable Values
1.	Horizontal Diaphragms
	Plywood sheathing applied directly over existing straight sheathing with ends of plywood sheets bearing on joists or rafters and edges of plywood located on center of individual sheathing boards.	Same as specified in Table 25-J of UBC, '88 Ed., for blocked diaphragms.
2.	Shear Walls
	a. Plywood sheathing applied directly over existing wood studs. No value shall be given to plywood applied over existing plaster or wood sheathing.	Same as values specified in UBC, '88 Ed., Table 25-K for shear walls.
	b. Dry wall or plaster applied directly over existing wood studs.	75% of the values specified in UBC, '88 Ed., Table #47-I.
	c. Dry wall or plaster applied to plywood sheathing over existing wood studs.	33 1/3 % of the value specified in UBC, '88 Ed., Table #47-I.
3.	Shear Bolts
	Shear bolts and dowels embedded a mm. of 8″ into unreinforced masonry walls. Bolt centered in a 2½″ diameter hole with dry-pack or non-shrink grout around circumference of bolt or dowel. 1, 3	100% of the value for plain masonry specified in UBC, '88 Ed., Table #24-G. No values larger than those given for ¾″ bolts shall be used.
4.	Tension Bolts
	Tension bolts and dowels extending entirely through unreinforced masonry walls secured w/bearing plates on far side of wall with at least 30 sq. ft. of area of area. 2, 3	1,200 lbs. per bolt or dowel.
5.	Wall Anchors (section 15.42.100B.1).
	Bolts extending to the exterior face of the wall with a 2½′ round plate under the head. Install as specified for shear bolts. Spaced not closer than 12′ on centers. 1, 2, 3	600 lbs. per bolt.
6.	Bolts or dowels extending to the exterior face of the wall with a 2½' round plate under the head and drill at an angle of 22½ degrees to the horizontal. Installed as specified for bolts. 1, 2, 3	1,200 lbs. per bolt or dowel.
7.	Infilled Walls
	Reinforced masonry infilled openings in existing unreinforced masonry walls with keys or dowels to match reinforcing.	Same as value specified for unreinforced masonry walls.
8.	Reinforced Masonry
	Masonry piers and walls reinforced per Sec. 2417, UBC, 88 Ed.	Same as values specified in Table #24-B, UBC, 1988 Ed.
9.	Reinforced Concrete
	Concrete footings, walls and piers reinforced as specified In Chapter 26, UBC, 1988 Ed., and designed for tributary loads.	Same as values specified Chapter 26, UBC, 1988 Ed.
10.	Existing Foundation Loads
	Foundation loads for structures exhibiting no evidence of settlement.	Calculated existing foundation loads due to maximum dead load + live load may be increased 25% for dead load, and may be increased 50% for dead load + seismic load required by this chapter.

1	Bolts and dowels to be tested as specified in section 15.42.090(f).
2	Bolts and dowels to be one-half inch minimum in diameter.
3	Drilling for bolts and dowels shall be done with an electric rotary drill. Impact tools shall not be used for drilling holes or tightening anchor and shear bolt nuts.

Table III-I ALLOWABLE SHEAR STRESS FOR TESTED UNREINFORCED MASONRY WALLS
80% of Test Results in PSI Not Less Than	Average Test Results of Cores in PSI	Seismic In-Plane Shear Based on Gross Area
30 plus axial stress	20	3 psi*
40 plus axial stress	27	4 psi*
50 plus axial stress	33	5 psi*
100 plus axial stress or more	67 or more	10 psi max*

*	Allowable shear stress may be increased by addition of ten percent of the axial stress due to the weight of the wall directly above.

Table III-K SERVICE PRIORITIES AND EXTENDED TIME PROVISIONS
Rating Classification	Occupant Load	Minimum Time Periods for Service of Order	Extension of Time After Wall Anchors are Installed
High risk building	100 or more	270 days	180 days
Medium risk building	More than 20 but less than 100	270 days	180 days
Low risk building	Less than 20	270 days	1 year

*	Measured from the effective date of this article.

Table III-L HORIZONTAL FORCE FACTORS BASED ON RATING CLASSIFICATION
Rating Classification	IKCS
High risk building	0.133
Medium/low risk building	0.100

Table III-M HORIZONTAL FORCE FACTOR "CP" FOR PARTS OR PORTIONS OF BUILDINGS OR OTHER STRUCTURES 1
Part of Portion of Building	Direction of Force	Value of CP
Exterior bearing and non-bearing walls, interior bearing walls and partitions, interior non-bearing walls and partitions over 10 inches in height, masonry fences over 6 inches in height.	Normal to flat surface	0.20
Cantilever parapet and other cantilever walls, except retaining walls.	Normal to flat surface	1.00
Exterior and interior ornamentations and appendages.	Any direction	1.00
When connected to or part of a building; towers, tanks, towers and tanks + contents racks over 8" 3' in height + contents, chimneys, smokestacks, and penthouses.	Any direction	0.24 2,4
When connected to or part of a building: Rigid and rigidly mounted equipment and machinery not required for continued operation of essential occupancies.	Any horizontal direction	0.20 3
Tanks + effective contents resting on ground.	Any direction	0.12
Floors and roofs acting as diaphragms.	In the plane of the diaphragm	0.12 6
Prefabricated structural elements, other than walls, with force applied at center of gravity of assembly.	Any horizontal direction	0.30
Connections for exterior panels or elements.	Any direction	2.0

1	See section 15.42.080(B) for use of CP
2	When located in the upper portion of any building with a ratio of 5 to 1 or greater the value shall be increased by 50 percent.
3	For flexible and flexibly mounted equipment and machinery, the appropriate values for CP shall be determined with consideration given to both the dynamic properties of the equipment and machinery, and to the building or structure in which it is placed.
4	The W for storage racks shall be the weight of the racks plus contents. The value of CP for racks over two storage support levels in height shall be 0.16 for the levels below the top two levels.
5	The design of the equipment and machinery and their anchorage is an integral part of the design and specification of such equipment and machinery. The structure to which the equipment or machinery is mounted shall be capable of resisting the anchorage forces (see also Section 2313(k), UBC, 1988 Edition).
6	Floor and roofs acting as diaphragms shall be designed for a minimum force resulting for a CP of 0.12 applied to W unless a greater force results from the distribution of lateral forces in accordance with Section 2312(e), USC, 1988 Edition.

(Code 1980, ch. 15.42, tables III-A—III-I, III-K—III-M; Ord. No. 417 § 4, 1990; Ord. No. 417-A, 1991; Ord. No. 870 (Recodification), 2014)