Rialto Municipal Code Ch. 15.56 Seismic Safety Provisions for Unreinforced Masonry Bearing Wall Buildings

Footnotes:

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Prior ordinance history: Ords. 1147 and 1234.

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 existing unreinforced masonry bearing wall buildings.

The provisions of this chapter are intended as minimum standards for structural seismic resistance and established primarily to reduce the risk of life loss or injury. Compliance with these provisions will not necessarily prevent loss of life or injury, or prevent earthquake damage to rehabilitated buildings.

(Ord. 1250 § 1 (part), 1996)

The provisions of this chapter shall apply to all existing buildings having at least one unreinforced masonry bearing wall. Except as provided herein, all other provisions of the building code shall apply.

Exceptions:

A. Detached one-family and two-family dwellings and detached apartment houses containing less than five dwelling units and used solely for residential purposes.

B. Unreinforced masonry bearing wall buildings constructed of hollow concrete blocks or hollow clay tiles, unless they do not exceed two stories in height and it can be shown by testing that the tile or block units are of bearing type and the capacity of the wall in bearing and shear based on net area in contact through bed joints is not less that those allowed for solid bricks. Bonding shall also be verified to the satisfaction of the local government agency.

(Ord. 1250 § 1 (part), 1996)

General. All buildings shall have a seismic resisting system conforming with Uniform Building Codes, Volumes 1, 2, and 3, Title 24 and other California Building Codes in effect.

(Ord. 1250 § 1 (part), 1996)

A. General. All materials permitted by this chapter, including their appropriate allowable design values and those existing configurations of materials specified herein, may be utilized to meet the requirements of this chapter.

B. Existing Materials. All existing materials utilized as part of the required vertical load-carrying or lateral force-resisting system shall be in sound condition or shall be repaired or removed and replaced with new materials.

C. Existing Unreinforced Masonry.

1. General. All unreinforced masonry walls utilized to carry vertical loads or seismic forces parallel and perpendicular to the wall plane shall be tested as specified in this subsection. All masonry that does not meet the minimum standards established by this chapter shall be removed and replaced with new materials or alternatively shall have its structural functions replaced with new materials and shall be anchored to supporting elements.

2. Lay-up of Walls. The facing and backing shall be bonded so that not less than ten percent of the exposed face area is composed of solid headers extending not less than four inches into the backing. The clear distance between adjacent full-length headers shall not exceed twenty-four inches vertically or horizontally.

Where the backing consists of two or more wythes, the headers shall extend not less than four inches into the most distant wythe or the backing wythes shall be bonded together with separate headers whose area and spacing conform to the foregoing. Wythes of walls not bonded as described above shall be considered as veneer. Veneer wythes shall not be included in the effective thickness used in calculating the height to thickness and the shear capacity of the wall.

3. Location of Tests. The shear tests shall be taken at locations representative of the mortar conditions throughout the entire building, taking into account variations in workmanship at different building height levels, variations in weathering of the exterior surfaces, and variations in the condition of the interior surfaces due to deterioration caused by leaks and condensation of water and/or by the deleterious effects of other substances contained within the building. The exact test location shall be determined at the building site by the engineer in responsible charge of the structural design work. An accurate record of all such tests and their location in the building shall be recorded and these results shall be submitted to the building department for approval as part of the structural analysis. Verification by a structural engineer.

(Ord. 1250 § 1 (part), 1996)

A. Pointing. All preparation and mortar pointing shall be performed with special inspection.

Exception: At the discretion of the chief building official or his/her designee, incidental pointing may be performed without special inspection.

B. Masonry Shear Tests. In-place masonry shear tests shall comply with U.B.C. Standard No. 2115.

C. Existing Wall Anchors. Existing wall anchors utilized as all or part of the required tension anchors shall be tested in pullout according to U.B.C. Standard No. 21-8. The minimum number of anchors tested shall be four per floor, with two tests at walls with joists framing into the wall, and two tests at walls with joists parallel to the wall, but not less than ten percent of the total number of existing tension anchors at each level.

D. New Bolts. One-fourth of all new shear bolts and combined tension and shear bolts in unreinforced masonry walls shall be tested according to the U.B.C. Standard No. 21-8.

Exception: Special inspection in accordance with Building Code may be provided during installation in lieu of testing.

(Ord. 1250 § 1 (part), 1996)

A. Definitions. For the purposes of this chapter, the applicable definitions in the Building Code shall also apply.

"High-risk building" is any building, other than an essential or hazardous building, having an occupant load of one hundred occupants or more as determined by Section 1002 of the Building Code.

Exceptions: A high-risk building shall not include the following:

1. Any building having exterior walls braced with masonry crosswalls or woodframe crosswalls spaced less than forty feet apart in each story. Crosswalls shall be full-story height with a minimum length of one and one-half times the story height.

2. Any building used for its intended purpose, as determined by the chief building official or his/her designee, for less than twenty hours per week.

"Low-risk building" means any building, other than an essential or hazardous building, having an occupant load as determined by Section 1002 of the Building Code of less than twenty occupants.

"Medium-risk building" is any building, not classified as a high-risk building or an essential or hazardous building, having an occupant load as determined by Section 1002 of the Building Code of twenty occupants or more.

B. Rating Classifications. The rating classifications identified in Table No. A-1-E are established and each building within the scope of this chapter shall be placed in one such rating classification by the chief building official or his/her designee. The total occupant load of the entire building as determined by Section 1002.1—1002.4 of the Building Code shall be used to determine the rating classification.

Exception: For purposes of this chapter, portions of buildings constructed to act independently when resisting seismic forces, and having required exits with independent travel paths, may be placed in separate rating classifications.

C. Compliance Requirements.

1. The owner of each building within the scope of this chapter shall, upon service of an order and within the time limits set forth in this chapter, cause a structural analysis to be made of the building by an engineer or architect licensed by the state to practice as such and, if the building does not comply with earthquake standards specified in this chapter, the owner shall cause it to be structurally altered to conform to such standards or shall cause the building to be demolished.

2. The owner of a building within the scope of this chapter shall comply with the requirements set forth above by submitting to the chief building official or his/her designee for review within the stated time limits:

a. Within two hundred seventy days after service of the order, a structural analysis, which is subject to approval by the chief building official or his/her designee, and which shall demonstrate that the building meets the minimum requirements of this chapter; or

b. Within two hundred seventy days after service of the order, the structural analysis and plans for structural alterations of the building to comply with this chapter; or

c. Within one hundred eighty days after service of the order, plans for the installation of wall anchors in accordance with the requirements specified in Section 15.56.110(C); or

d. Within two hundred seventy days after service of the order, plans for the demolition of the building.

3. After plans are submitted and approved by the chief building official or his/her designee, the owner shall obtain a building permit and then commence and complete the required construction or demolition within the time limits set forth in Table No. B of this chapter.

4. This chapter does not require alteration of existing electrical, plumbing, mechanical or fire-safety systems.

D. Administration.

1. Order—Service.

a. The chief building official or his/her designee shall, in accordance with the priorities set forth in Table No. B, issue an order as provided in this section to the owner of each building within the scope of this chapter.

b. Prior to the service of an order as set forth in Table No. A of this chapter, a bulletin may be issued to the owner as shown upon the last equalized assessment roll or to the person in apparent charge or control of a building considered by the building official to be within the scope of this chapter. The bulletin may contain information the chief building official or his/her designee deems appropriate. The bulletin may be issued by mail or in person.

2. Order—Priority of Service. Priorities for the service of the order for buildings within the scope of this chapter shall be in accordance with the rating classification as shown on Table No. B of this chapter. Within each separate rating classification, the priority of the order shall normally be based upon the occupant load of the building. The owners of the buildings housing the largest occupant loads shall be served first. The minimum time period prior to the service of the order as shown on Table No. A of this chapter shall be measured from the effective date of the ordinance codified in this chapter. The chief building official or his/her designee may, upon receipt of written request from the owner, order such owner to bring his/her building into compliance with this chapter prior to the normal service date for such building set forth in this chapter.

3. Order—Contents. The order shall be in writing and shall be served either personally or be certified or registered mail upon the owner as shown on the last equalized assessment roll, and upon the person, if any, in apparent charge to control of the building. The order shall specify that the building has been determined by the chief building official or his/her designee to be within the scope of this chapter and, therefore, 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 a copy of Section 15.56.110(C), which sets forth the owner's alternatives and time limits for compliance.

4. Recordation. At the time that the chief building official or his/her designee serves the aforementioned order, the chief building official or his/her designee shall also file with the office of the county recorder a certificate stating that the subject building is within the scope of this chapter and is a potentially earthquake hazardous building. The certificate shall also state that the owner thereof has been ordered to structurally analyze the building and to structurally alter or demolish it where compliance with this chapter has not been demonstrated.

If the building is either demolished, found not to be within the scope of this chapter, or is structurally capable of resisting minimum seismic forces required by this chapter as a result of structural alterations or an analysis, the chief building official or his/her designee shall file with the office of the county recorder a form terminating the status of the subject building as being classified within the scope of this chapter.

5. Enforcement. If the owner in charge or control of the subject building fails to comply with any order issued by the chief building official or his/her designee pursuant to this chapter within any of the time limits set forth in subsection C of this section, the chief building official or his/her designee shall verify that the record owner of this building has been properly served. If the order has been served on the record owner, then the chief building official or his/her designee 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 has not been accomplished within ninety days after the date the building has been ordered vacated or such additional time as may have been granted by the board of appeals, the chief building official or his/her designee may order its demolition in accordance with the provisions of Section 102 of the Building Code.

Table No. A

Rating Classifications

Table No. B

Time Limits for Compliance

1. Measured from date of service of order.

2. Measured from date of building permit issuance.

Chapter 15.56 TABLE NO. C

EXTENSIONS OF TIME AND SERVICE PRIORITIES

1

All strengthening required by this chapter shall be completed by January 1, 1995.

Chapter 15.56 TABLE NO. D

ELEMENTS REGULATED BY THIS CHAPTER

1

Applies only to buildings designed according to the special provisions of Uniform Building Codes Volumes 1, 2 and 3.