Long Beach Municipal Code Ch. 18.72 Voluntary Earthquake Hazard Reduction in Existing Reinforced Concrete…

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 reinforced concrete and masonry wall buildings with flexible diaphragms designed under the Building Codes in effect prior to January 1, 1995. These buildings are potentially hazardous and prone to significant damage, including possible collapse, in a moderate to major earthquake. These structures typically shelter large numbers of persons and property for retail, food markets, food distribution centers, warehousing, aerospace, industrial/manufacturing and general business and office use. Their continued use after an earthquake is also essential to the local economy and its post-earthquake recovery.

The provisions of this chapter are minimum standards for structural seismic resistance established primarily to reduce the risk of loss of life or injury on both subject and adjacent properties and will not necessarily prevent all 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.

This chapter provides voluntary retrofit standards for deficient wall anchorage systems on structures that are not subject to the mandatory provisions of Chapter 18.68. When fully followed, these standards will strengthen the portion of the structure that is most vulnerable to earthquake damage.

(ORD-25-0019 § 1(Exh. A), 2025; ORD-22-0033 § 1(Exh. A), 2022; ORD-19-0031 § 1(Exh. A), 2019; ORD-16-0026 § 1(Exh. A), 2016)

The voluntary provisions of this chapter shall apply to existing buildings of the following types:

A. Cast-in-place reinforced concrete or masonry wall buildings with flexible diaphragms designed under Building Codes in effect prior to January 1, 1995.

B. Tilt-up concrete wall buildings with flexible diaphragms designed under the Building Codes in effect prior to January 1, 1995, but after January 1, 1976. All existing reinforced masonry or concrete buildings with flexible diaphragms, including tilt-up concrete wall buildings, designed under the Building Code in effect on or after January 1, 1995, shall be designed in conformance with Chapter 16 of the California Building Code adopted in Chapter 18.40.

(ORD-25-0019 § 1(Exh. A), 2025; ORD-22-0033 § 1(Exh. A), 2022; ORD-19-0031 § 1(Exh. A), 2019; ORD-16-0026 § 1(Exh. A), 2016)

For the purposes of this chapter, the applicable definitions in Chapter 2, Section 1602 of the California Building Code adopted in Chapter 18.40; Sections 1.2, 3.1.1, 4.1, 5.2, 6.2 and 11.2 of ASCE 7-16, and the following shall apply:

"Anchorage system" means the system of all structural elements and connections which support the concrete or masonry wall in the lateral direction, including diaphragms and subdiaphragms, wall anchorage and continuity or crosstie connectors in subdiaphragms and main diaphragms.

"Commenced construction" means construction pursuant to a valid building permit that has progressed to the point that one of the called inspections as required by the Department has been made and the work for which the inspection has been called has been judged by the Department to be substantial and has been approved by the Department.

"Existing building" means an erected building for which a legal building permit and a Certificate of Occupancy have been issued.

"Flexible diaphragm" means any diaphragm constructed of wood structural panel, diagonal or straight wood sheathing, metal decking without a structural concrete topping, or horizontal rod bracing.

"Historical building" means any building designated or currently in the process of being designated as a historical building by an appropriate federal, State or City jurisdiction.

"Reinforced concrete wall" means a concrete wall which has fifty percent (50%) or more of the reinforcing steel required for reinforced concrete in Chapter 19 of the California Building Code adopted in Chapter 18.40.

"Reinforced masonry wall" means a masonry wall which has fifty percent (50%) or more of the reinforcing steel required by Section 2106.1 of the California Building Code adopted in Chapter 18.40.

"Retrofit" strengthens or structurally improves the lateral force-resisting system of an existing building by alteration of existing or addition of new structural elements.

"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 and moved into place in a vertical position, or cast off-site in a fabricator's shop.

(ORD-25-0019 § 1(Exh. A), 2025; ORD-22-0033 § 1(Exh. A), 2022; ORD-19-0031 § 1(Exh. A), 2019; ORD-16-0026 § 1(Exh. A), 2016)

A. 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 thirty percent (30%) of the tributary wall weight for all buildings, and forty-five percent (45%) of the tributary wall weight for essential buildings, or a minimum force of two hundred fifty (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: An alternate design may be approved by the Building Official when justified by well-established principles of mechanics.

B. 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 one-third (⅓) stress increase permitted by Section 1605.2 of the California Building Code adopted in Chapter 18.40 shall not be permitted for materials using allowable stress design methods.

The strength design specified in Section 1605 of the California Building Code adopted in Chapter 18.40, using a load factor of 1.43 in lieu of 1.0 for earthquake loading, shall be used for the design of embedment 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 registered design professional 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 seismic loading. Criteria for analysis and testing shall be determined by the Building Official.

Expansion anchors are not allowed without special approval of the Building Official. Attaching the edge of plywood sheathing to steel ledgers is not considered as complying with the positive anchoring requirements of the code; and attaching the edge of steel decks to steel ledgers is not considered as providing the positive anchorage of this code unless testing and analysis are performed which establish shear values for the attachment perpendicular to the edge of the deck.

C. Development of anchor loads into the diaphragm. Development of anchor loads into roof and floor diaphragms shall comply with Section 12.11.2.2.3 of ASCE 7-16.

EXCEPTION: If continuously tied girders are present, then the maximum spacing of the continuity ties is the greater of the girder spacing or twenty-four (24) feet.

In wood diaphragms, anchorage shall not be accomplished by use of toenails 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 Section 12.11.2.2.3 of ASCE 7-16 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, or the tributary shear but not exceeding the capacity of the diaphragm. Shear anchors for the return wall 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 or shear capacity of the return wall is governing.

D. Anchorage at pilasters. Anchorage of pilasters shall be designed for the tributary wall anchoring load per Subsection 18.72.040.A, considering the wall as a two-way slab. The edge of the two-way slab shall be considered "fixed" when there is continuity at pilasters, and considered "pinned" at roof or floor levels. 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 bypassed 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 Subsection 18.72.040.A.

E. 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.

F. Minimum member size. Wood members used to develop anchorage forces to the diaphragm shall be of minimum three-inch nominal width for new construction and replacement. All such members must be designed for gravity and earthquake forces as part of the wall anchorage system. For existing structural members, the allowable stresses shall be without the one-third (⅓) stress increase per Subsection 18.72.040.B.

G. 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.

H. Prohibited anchors. Usage of connectors that were bent or stretched from the intended use shall be prohibited.

I. Crack and damage repairs, evaluation of existing structural alterations. The registered design professional shall report any observed structural conditions and structural damage that have imminent life-safety effects on the buildings and recommend repairs, including alterations such as openings cut in existing wall panels without a building permit. Evaluations and repairs shall be reviewed and approved by the Department.

J. Miscellaneous. Existing mezzanines relying on the concrete or masonry walls for vertical 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 Subsections 18.72.040.A through 18.72.040.C.

EXCEPTION: Existing mezzanines that have independent lateral and vertical support need not be anchored to the concrete or masonry walls.

Existing interior masonry or concrete walls not designed as shear walls, which extend to the floor above or to the roof diaphragm, shall also be anchored for out-of-plane forces per Subsections 18.72.040.A through 18.72.040.C. 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.

K. Historical buildings. Qualified historical buildings shall be permitted to use alternate building standards or deviations from this chapter in order to preserve their original or restored architectural elements and features. See California Code of Regulations, Title 24, Part 8 (California Historical Building Code) for these standards.

(ORD-25-0019 § 1(Exh. A), 2025; ORD-22-0033 § 1(Exh. A), 2022; ORD-19-0031 § 1(Exh. A), 2019; ORD-16-0026 § 1(Exh. A), 2016)

All materials permitted by this title, including their appropriate allowable stresses and those existing configurations of materials specified in Chapter 18.68, may be utilized to meet the requirements of this chapter.

(ORD-25-0019 § 1(Exh. A), 2025; ORD-22-0033 § 1(Exh. A), 2022; ORD-19-0031 § 1(Exh. A), 2019; ORD-16-0026 § 1(Exh. A), 2016)

A. General. In addition to the seismic analysis required elsewhere in this chapter, the licensed registered design professional responsible for the seismic analysis of the building shall record the information required by this section on the approved construction documents.

B. Information required. The construction documents shall accurately reflect the results of the engineering investigation and design and show all pertinent dimensions and sizes for plan review and construction. The following shall be provided:

1. Floor plans and roof plans shall show the existing framing construction, diaphragm construction, proposed wall anchors, crossties 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.

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

3. Typical concrete or masonry wall sections with wall thickness, height and location of anchors shall be provided.

4. Details shall include the existing and new anchors and the method of development of anchor forces into the diaphragm framing, existing and new crossties, existing and new or improved support of the roof, and floor girders at pilasters or walls.

C. Registered design professional of record's statement. The responsible registered design professional of record shall state on the approved construction documents the following:

1. "I am responsible for this building's seismic strengthening design of the tilt-up concrete wall anchorage system in compliance with the minimum seismic resistance standards of Chapter 18.72 of the Long Beach Municipal Code."

Or when applicable:

2. "The Registered Special Inspector, required as a condition of the use of structural design stresses requiring continuous inspection, will be responsible to me."

(ORD-25-0019 § 1(Exh. A), 2025; ORD-22-0033 § 1(Exh. A), 2022; ORD-19-0031 § 1(Exh. A), 2019; ORD-16-0026 § 1(Exh. A), 2016)