Los Angeles County Municipal Code § 12.11 Structural Design

The anchorage of concrete or masonry structural walls to wood diaphragms shall be in accordance with AWC SDPWS 4.1.5.1 and this Section. Continuous ties required by this Section shall be in addition to the diaphragm sheathing. Anchorage shall not be accomplished by use of toenails or nails subject to withdrawal, nor shall wood ledgers or framing be used in cross-grain bending or cross-grain tension. The diaphragm sheathing shall not be considered effective as providing ties or struts required by this Section.

For structures assigned to Seismic Design Category D, E, or F, wood diaphragms supporting concrete or masonry walls shall comply with the following:

The spacing of continuous ties shall not exceed 40 feet. Added chords of diaphragms may be used to form subdiaphragms to transmit the anchorage forces to the main continuous crossties.

The maximum diaphragm shear used to determine the depth of the subdiaphragm shall not exceed 75 percent of the maximum diaphragm shear.

1613.8.3   ASCE 7, 12.12.3.

Modify ASCE 7, Section 12.12.2, to read as follows:

All portions of the structure shall be designed and constructed to act as an integral unit in resisting seismic forces unless separated structurally by a distance suf?cient to avoid damaging contact as set forth in this section.

Separations shall allow for the Maximum Design Earthquake Displacements, δMDE, as determined in accordance with Equation 12.12-1:

δMDE = C d δ e + δ di

(Equation 12.12-1)

(Ord. 2025-0047 § 21, 2025.)