[DSA-SS/CC] Division of the State Architect-Structural Safety/Community Colleges (DSA-SS/CC) amendments appear in this chapter preceded with the appropriate acronym, as follows:
Division of the State Architect - Structural Safety/Community Colleges: [DSA-SS/CC] - For community college buildings listed in Section 126.96.36.199
- Glazing of openings in exterior walls;
- Anchorage of post and beam construction;
- Cantilever overhangs; and
- Roofing and roof framing.
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% of the maximum diaphragm shear.
Where determining the moments and shears induced in components that are not included in the seismic force-resisting system in the direction under consideration, the stiffening effects of adjoining rigid structural and nonstructural elements shall be considered and a rational value of member and restraint stiffness shall be used.
When designing the diaphragm to comply with the requirements stated above, the return walls and fins/canopies at entrances shall be considered. Seismic compatibility with the diaphragm shall be provided by either seismically isolating the element or by attaching the element and integrating its load into the diaphragm.
- The structure does not have irregularities, as defined in ASCE 7 Section 12.3.2;
- The structure does not exceed five stories above the lower of the base or grade plane as defined in ASCE 7 Section 11.2; and, where present, each mezzanine level shall be considered a story for the purpose of this limit;
- The structure has a fundamental period, T, that does not exceed 0.5 seconds, as determined using ASCE 7 Section 12.8.2;
- The structure meets the requirements necessary for the redundancy factor p, to be permitted to be taken as 1.0, in accordance with ASCE 7 Section 188.8.131.52;
- The site soil properties are not classified as Site Classes E or F, as defined in ASCE 7 Section 11.4.2; and
- The structure is classified as Risk Category I or II, as defined in ASCE 7 Section 1.5.1.
Sprinkler heads penetrating fire-resistance-rated floor/ceiling or roof/ceiling assemblies shall comply with CBC Section 714. Sprinkler heads and other penetrations shall have a 2 in. (50 mm) oversize ring, sleeve or adapter through the ceiling tile to allow for free movement of at least 1 in. (25 mm) in all horizontal directions. Alternatively, a swing joint that can accommodate 1 in. (25 mm) of ceiling movement in all horizontal directions is permitted to be provided at the top of the sprinkler head extension.
DIAPHRAGM ANCHORS are assemblies that connect a diaphragm to the adjacent foundation at the uphill diaphragm edge.
DOWNHILL DIRECTION is the descending direction of the slope approximately perpendicular to the slope contours.
FOUNDATION is concrete or masonry, which supports a building, including footings, stem walls, retaining walls, and grade beams.
FOUNDATION EXTENDING IN THE DOWNHILL DIRECTION is a foundation running downhill and approximately perpendicular to the uphill foundation.
HILLSIDE BUILDING is any building or portion thereof constructed on or into a slope steeper than one unit vertical in three units horizontal (33.3%). If only a portion of the building is supported on or into the slope, these regulations apply to the entire building.
PRIMARY ANCHORS are diaphragm anchors designed for and providing a direct connection as described in LAMC Subdivision 91.1613.9.5 and Paragraph 91.16184.108.40.206 between the diaphragm and the uphill foundation.
SECONDARY ANCHORS are diaphragm anchors designed for and providing a redundant diaphragm to foundation connection, as describe in LAMC Subdivision 91.1613.9.6 and Paragraph 91.16220.127.116.11.
UPHILL DIAPHRAGM EDGE is the edge of the diaphragm adjacent and closest to the highest ground level at the perimeter of the diaphragm.
UPHILL FOUNDATION is the foundation parallel and closest to the uphill diaphragm edge.
- Wood structural panel wall sheathing,
- Cement plaster and lath,
- Gypsum wallboard, and
- Tension only braced frames.