Burbank Municipal Code Div. 2 Earthquake Hazard Reduction in Existing Reinforced Concrete Wall and/Or…

BUILDINGS WITH FLEXIBLE DIAPHRAGMS:

9-1-16-200.1: PURPOSE:

The City of Burbank is within California Building Code Seismic Zone 4. This is the highest risk for damaging earthquakes. Approximately 30 percent of the City is categorized as an “Active Fault Near-Source Zone” (ICBO, California Department of Conservation-Division of Mines and Geology). The Near-Source Zone is an area within two kilometers of an active fault (Class A or B) capable of producing a major earthquake. The Verdugo Fault and the Hollywood Fault are the near-source influences for the City (both are Class B faults). A Near-Source Zone is subject to the largest and most damaging ground acceleration and velocity produced in a seismic event. The resulting structural damage in a near-source zone is generally severe.

The 1994 Northridge Earthquake caused considerable damage to buildings and structures located in the City of Burbank. Experts expect a massive earthquake on one of the faults under the City within the next 30 years and several earthquakes similar in intensity to the Northridge Earthquake during that same period.

The damage to buildings could expose occupants of these buildings to a potential life-safety risk in future earthquakes, and the City of Burbank must protect its population and property and enforce the Building Code so as to provide effective protection to all its citizens.

Recent earthquakes, including the 1994 Northridge event, have demonstrated the deficiencies in the structural performance of reinforced concrete wall and/or reinforced masonry wall buildings with flexible diaphragms. The 1997 California Building Code contained revisions to the seismic requirements for new construction, but it did not address the existing “legal nonconforming” buildings.

Pre-1976 UBC reinforced concrete wall and/or reinforced masonry wall buildings with flexible diaphragms are considered potentially hazardous and prone to significant damage, including possible roof collapse, in moderate to major earthquakes. These buildings may lack adequate strength in the anchorage system of the wall to the roof and floor diaphragms.

The purpose of this section is to promote public safety and welfare by reducing the risk of death or injury that may result from the effects of earthquakes on reinforced concrete wall and/or reinforced masonry wall buildings with flexible diaphragms designed under the building codes in effect prior to the adoption of the 1976 UBC. Such buildings have been categorized, based on past earthquakes, as being potentially hazardous and prone to significant damage, including possible collapse, in a moderate to major earthquake.

The provisions of this section are minimum standards for structural seismic resistance established primarily to reduce the risk of life loss or injury on both subject and adjacent properties and will not necessarily prevent loss of life or injury or prevent earthquake damage to an existing building which complies with these standards. The requirement for compliance with these standards does not preclude the utilization, at the building owner’s option, of more extensive strengthening method that might further prevent or limit loss of life or injury or building damage. This section shall not require existing electrical, plumbing, mechanical or fire-safety systems to be altered unless they constitute a hazard to life or property.

This section provides for the identification and classification of reinforced concrete wall and/or reinforced masonry wall buildings with flexible diaphragms based on the current use of the building. Priorities, time periods, and standards are also established under which these buildings are required to be structurally analyzed and strengthened for seismic resistance. Where the analysis determines structural deficiencies, this section requires the building to be strengthened. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.2: SCOPE:

The provisions of this section shall apply to all buildings designed under building codes in effect prior to February 14, 1977, which, on the effective date of this section have reinforced concrete walls and/or reinforced masonry walls with flexible diaphragms as defined herein.

Any such buildings with seismic strengthening in place prior to the effective date of this ordinance shall be within the scope of this section and shall, therefore, be evaluated according to the provisions of this section and modified to comply with this section if deficient. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.3: DEFINITIONS:

ANCHORAGE SYSTEM: Is the system of all structural elements and connections which support the concrete or masonry wall in the lateral direction, including diaphragms and sub-diaphragms, wall anchorage and continuity or cross tie connectors in sub-diaphragms and main diaphragms.

COMMENCED CONSTRUCTION: Construction pursuant to a valid building permit has progressed to the point that one of the called inspections as required by the City has been made and the work for which the inspection has been called has been judged by the City to be substantial and has been approved by the Building Official.

FLEXIBLE DIAPHRAGM: Is any diaphragm constructed of wood structural panel, diagonal or straight wood sheathing, metal decking without a structural concrete topping, or horizontal rod bracing.

REINFORCED CONCRETE WALL: Is a concrete wall that has 50 percent or more of the reinforcing steel required for reinforced concrete in the Uniform Building Code.

REINFORCED MASONRY WALL: Is a masonry wall that has 50 percent or more of the reinforcing steel required by 1976 Uniform Building Code Section 2106.1.12.4.

TILT-UP CONCRETE WALL: Is a form of precast concrete panel construction either cast in the horizontal position at the site and after curing, lifted into place in a vertical position, or cast off-site in a fabricator’s shop. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.4: RATING CLASSIFICATIONS:

The rating classifications as shown in Table No. 9-1-16-200-A are hereby established and each building within the scope of this section shall be placed in one such rating classification by the Building Official. The total occupant load as determined by CBC Chapter 10 for the entire building plus the occupant load of any adjacent building which interconnects with the subject building or uses the subject building for exiting purposes shall be used to determine the rating classification. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.5: INSPECTION AND RETROFIT REQUIRED; SIGN REQUIRED:

A. The owner of each building within the scope of this section shall cause an investigation of the existing construction and a structural analysis to be made of the building by a civil or structural engineer or architect licensed by the State of California, and if the building does not meet the minimum standards specified in this section, the owner shall cause the building to be structurally altered to conform to such standards or cause the building to be demolished. The owner of a building within the scope of this section shall submit to the Building Official within 275 days after the service of the compliance order the following for review:

1. A structural analysis, subject to approval by the Building Official within the 275-day time period, which demonstrates that the building meets the minimum requirements of this Section, or

2. A structural analysis and plans for the proposed structural alterations of the building necessary to comply with the minimum requirements of this Section, or

3. Plans for the demolition of the building.

After plans are submitted and approved by the Building Official, the owner shall obtain a building permit, commence and complete the required construction or demolition within the time limits set forth in Table No. 9-1-16-200-B. These time limits shall begin to run from the date the compliance order is served.

B. Unless exempt pursuant to 9-1-16-200.5(C) below, the owner or person in charge or control of a building within the scope of this section shall, within 275 days after the service of a compliance order, post in a conspicuous place at the entrance of the building, on a sign not less than 8-1/2" x 11", the following statement, printed in not less than 30 point bold type: “This is a reinforced concrete wall or reinforced masonry wall building with a flexible diaphragm built prior to February 14, 1977. The City of Burbank has ordered the owner of this building to bring the building into compliance with the provisions of Burbank Municipal Code Section 9-1-16-200, which relate to earthquake safety.”

C. The sign shall remain posted until the structural alterations bringing the building into compliance with the provisions of Section 9-1-16-200 are completed and approved by the Building Official. If an owner of a building within the scope of this section has submitted to the Building official a structural analysis that demonstrates that the building meets the minimum requirements of Section 9-1-16-200 and the Building Official approves such structural analysis, the sign requirements in 9-1-16-200.5(B) shall no longer be applicable to such building. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.6: COMPLIANCE ORDER:

A. The Building Official shall issue a written compliance order to the record owner of each building within the scope of this section directing the owner to comply with this section and shall also mail a copy to the person, if any, occupying or otherwise in real or apparent charge and control of the building.

B. The order shall be served either personally or by mail and shall contain:

1. The street address and legal description sufficient for identification of the building.

2. A statement that the Building Official has found the building to be within the scope of Section 9-1-16-200.

3. An order to prepare and submit to the Building Official a structural analysis and plans pursuant to Section 9-1-16-200.5.

4. A statement specifying the appeal rights of the owner as contained in Section 9-1-16-200.7.

C. The order shall be served and contents recorded in accordance with the provisions of Article 13 of this Code. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.7: APPEAL FROM ORDER:

A. The owner of the building may appeal the Building Official’s determination that the building is within the scope of this section to the Board of Building and Fire Code Appeals. Such appeal shall be filed with the Board within 60 days of the service date of the order described in Section 9-1-16-200.6. Such appeal shall be made in writing upon appropriate forms provided therefore by the Building Division, and the grounds thereof shall be stated clearly and concisely. Any materials that the appellant wishes considered by the Board shall be submitted to the Board at least 14 calendar days before the hearing. Each appeal shall be accompanied by a filing fee as set forth in the Burbank Fee Resolution. If no appeal is filed within 60 days of the service of the compliance order, the building shall be considered to be within the scope of this Section 9-1-16-200.

B. Appeals or requests for modification from any other determinations, orders, or actions of the Building Official pursuant to this Section shall be made in accordance with the procedures established in Section 9-1-1-113 of this Code. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.8: TIME EXTENSIONS:

An owner of a building may apply to the Board of Building and Fire Code Appeals for an extension of time limits to submit a plan for retrofit of the building, to obtain necessary permits and/or to complete the retrofit to the building. The Board may grant an applicant an extension of up to 12 months additional time to comply with these requirements provided the applicant has demonstrated a good faith effort to meet the requirements of this Section 9-1-16-200. A maximum of two such extensions may be granted for a total extension of up to two years. In no case, shall the time for completion of retrofit exceed five years from the time of service of the compliance order. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.9: NO ALTERATIONS PERMITTED UNTIL BUILDING RETROFIT IS COMPLETE:

Once a compliance order has been served, buildings within the scope of this Section 9-1-16-200 may not be structurally altered, remodeled or added to, without first complying with the provisions of this Section 9-1-16-200 unless the Building Official determines that the alteration is minor in nature. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.10: ENFORCEMENT:

If the owner of the subject building fails to comply with any order issued by the Building Official pursuant to this section within any of the time limits set forth in Section 9-1-16-200.5, or within any additional time limits as may have been granted by the Board, the Building Official may order that the building be vacated until the building is in compliance. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11: ANALYSIS AND DESIGN:

The owner of a building subject to this Section shall cause the structure to comply with the following provisions. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.1: WALL PANEL ANCHORAGE:

Concrete and masonry walls shall be anchored to all floors and roofs which provide lateral support for the wall. The anchorage shall provide a positive direct connection between the wall and floor or roof construction capable of resisting a horizontal force equal to 30 percent of the tributary wall weight for all buildings, and 45 percent of the tributary wall weight for essential buildings, or a minimum force of 250 pounds per linear foot of wall, whichever is greater. The required anchorage shall be based on the tributary wall panel assuming simple supports at floors and roof.

EXCEPTION: Alternate design may be approved by the Building and Safety Division when justified by well-established principles of mechanics. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.2: SPECIAL REQUIREMENTS FOR WALL ANCHORS AND CONTINUITY TIES:

The steel elements of the wall anchorage systems and continuity ties shall be designed by the allowable stress design method using a load factor of 1.7. The 1/3 stress increase permitted by 1976 UBC Section 1603.5 shall not be permitted for materials using allowable stress design methods. The strength design specified in 1994 UBC Section 1925.2, using a load factor of 2.0 in lieu of 1.4 for earthquake loading, shall be used for design of embedments in concrete. Wall anchors shall be provided to resist out-of-plane forces, independent of existing shear anchors.

EXCEPTION: Existing cast-in-place shear anchors may be used as wall anchors if the tie element can be readily attached to the anchors and if the engineer or architect can establish tension values for the existing anchors through the use of approved as-built plans or testing, and through analysis showing that the bolts are capable of resisting the total shear load while being acted upon by the maximum tension force due to earthquake. Criteria for analysis and testing shall be determined by the Building Division.

Expansion anchors are not allowed without special approval of the Building Division. Attaching the edge of plywood sheathing to steel ledgers is not considered as complying with the positive anchoring requirements of this Section; and attaching the edge of steel decks to steel ledgers is not considered as providing the positive anchorage of this Section unless testing and analysis are performed that establish shear values for the attachment perpendicular to the edge of the deck. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.3: DEVELOPMENT OF ANCHOR LOADS INTO THE DIAPHRAGM:

Development of anchor loads into roof and floor diaphragms shall comply with 1994 UBC Section 1631.2.9.3.

EXCEPTION: If continuously tied girders are present, then the maximum spacing of the continuity ties is the greater of the girder spacing or 24 feet. In wood diaphragms, anchorage shall not be accomplished by use of toe nails or nails subject to withdrawal, nor shall wood ledgers, top plates or framing be used in cross-grain bending or cross-grain tension. The continuous ties required by 1976 UBC Section 1633.2.9.4 shall be in addition to the diaphragm sheathing.

Lengths of development of anchor loads in wood diaphragms shall be based on existing field nailing of the sheathing unless existing edge nailing is positively identified on the original construction plans or at the site.

At reentrant corners, continuity collectors may be required for existing return walls not designed as shear walls, to develop into the diaphragm a force equal to the lesser of the rocking or shear capacity of the return wall, to the tributary shear by not exceeding the capacity of the diaphragm. Shear anchors for the return shall be commensurate with the collector force. If a truss or beam other than rafters or purlins is supported by the return wall or by a column integral with the return wall, an independent secondary column is required to support the roof or floor members whenever rocking of shear capacity of the return wall is governing.

The design for the seismic deflection of return walls, and fins/canopies at entrances, shall insure deflection compatibility with the diaphragm by either seismically isolating the element or attaching the element and integrating its load into the diaphragm. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.4: ANCHORAGE AT PILASTERS:

Anchorage of pilasters shall be designed for the tributary wall anchoring load pursuant to Section 9-1-16-200.11.1, considering the wall as a two-way slab. The pilasters or the walls immediately adjacent to the pilasters shall be anchored directly to the roof framing such that the existing vertical anchor bolts at the top of the pilasters are by-passed without causing tension or shear failure at the top of the pilasters.

EXCEPTION: If existing vertical anchor bolts at the top of the pilasters are used for the anchorage, then additional exterior confinement shall be provided.

The minimum anchorage at a floor or roof between the pilasters shall be that specified in Section 9-1-16-200.11.1 of this Section. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.5: SYMMETRY:

Symmetry of connectors in the anchorage system is required. Eccentricity may be allowed when it can be shown that all components of forces are positively resisted and justified by calculations or tests. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.6: MINIMUM ROOF MEMBER SIZE:

Wood members used to develop anchorage forces to the diaphragm must be at least 3x for new construction and replacement. All such members must be checked for gravity and earthquake as part of the wall anchorage system. For existing buildings, the member check shall be without the 1/3 stress increase pursuant to Section 9-1-16-200.11.2. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.7: COMBINATION OF ANCHOR TYPES:

To repair and retrofit existing buildings, a combination of different anchor types of different behavior or stiffness shall not be permitted. The capacity of the new and existing connectors cannot be added. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.8: PROHIBITED ANCHORS:

Usage of connectors that were bent and/or stretched from the intended use shall be prohibited. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.9: CRACK AND DAMAGE REPAIRS, EVALUATION OF EXISTING STRUCTURAL ALTERATIONS:

The engineer shall report any observed structural conditions and structural damage that have imminent life safety effects on the buildings and recommend repairs. Evaluations and repairs shall be reviewed and approved by the Building and Safety Division. The engineer shall also evaluate the effects of alterations such as openings cut in existing wall panels without a permit that may present immediate life safety hazard, and correct when necessary. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.11.10: MISCELLANEOUS:

Existing mezzanines relying on the tilt-up walls for vertical and/or lateral support shall be anchored to the walls for the tributary mezzanine load. Walls depending on the mezzanine for lateral support shall be anchored per Sections 9-1-16-200.11.1, 9-1-16-200.11.2 and 9-1-16-200.11.3.

EXCEPTION: Existing mezzanines that have independent lateral and vertical support need not be anchored to the walls. Existing interior masonry or concrete walls not designed as shear walls, that extend to the floor above or to the roof diaphragm shall also be anchored for out-of-plane forces per Sections 9-1-16-200.11.1, 9-1-16-200.11.2 and 9-1-16-200.11.3 of this Code. In the in-plane direction, the walls may be isolated or shall be developed into the diaphragm for a lateral force equal to the lesser of the rocking or shear capacity of the wall, or the tributary shear but not exceeding the diaphragm capacity. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.12: MATERIALS OF CONSTRUCTION:

All materials permitted by this Code, including their appropriate allowable stresses and those existing configurations of materials specified in this Code, may be utilized to meet the requirements of this Section. [Added by Ord. No. 25-4,034, eff. 1/1/26.]

9-1-16-200.13: INFORMATION REQUIRED ON PLANS:

The plans shall accurately reflect the results of the engineering investigation and design and show all pertinent dimensions and sizes for plan review and construction. In addition to the seismic analysis required elsewhere in this Section, the licensed engineer or architect responsible for the seismic analysis of the building shall record the following on the approved plans:

A. Floor plans and roof plans shall show existing framing construction, diaphragm construction, proposed wall anchors, cross-ties and collectors. Existing nailing, anchors, ties and collectors shall also be shown on the plans if these are part of the design, and these structural elements need to be verified in the field.

B. At elevations where there are alterations or damage, details shall show roof and floor heights, dimensions of openings, location and extent of existing damage, and proposed repair.

C. Typical wall panel sections with panel thickness, height, location of anchors shall be provided.

D. Details shall include existing and new anchors and the method of development of anchor forces into the diaphragm framing; existing and/or new cross-ties; existing and/or new or improved support of roof and floor girders at pilasters or walls.

TABLE NO. 9-1-16-200-A RATING CLASSIFICATIONS

Classification/Occupant Load

Group I 300 or Group II 30 to 299 Group III less than more 30

TABLE NO. 9-1-16-200-B TIME LIMITS FOR COMPLIANCE

Obtain Building Commence Complete Permit Within Construction Construction

365 days 545 days Three years

TABLE NO. 9-1-16-200-C SERVICE PRIORITIES

Rating/Minimum Time Period Classification Before Service of Compliance Order

Group I 30 days Group II 1 year Group III 2 years

[Added by Ord. No. 25-4,034, eff. 1/1/26.]