Title 18 — LONG BEACH BUILDING STANDARDS CODE›Chapter 18.71 — VOLUNTARY EARTHQUAKE HAZARD REDUCTION IN EXISTING REINFORCED
§ 12.3
Long Beach Municipal Code · 2026-09 edition · updated 2026-10-02 · Long Beach
Section 12.3-2.¶
b.
Structures having one or more of the features listed in Table 12.3-2 of ASCE 7-16 shall be designated as having a vertical irregularity.
EXCEPTION: Where none of the story drift ratios under equivalent lateral forces is greater than 1.3 times the story drift ratio of the story above, the structure may be deemed to not have the structural irregularities of Type 1 or 2 listed in Table 12.3-2 of ASCE 7-16. The story drift for this determination shall be calculated including torsional effects.
c.
Structures having one (1) or more of the features listed in Table 12.3-1 of ASCE 7-16 shall be designated as having a plan irregularity.
d.
Irregular structures conforming to the requirements of Subsection 18.71.050.D and Section 18.71.080 may be considered regular if the plan and vertical irregularities are removed by the addition of lateral load- resisting systems.
D.
Selection of lateral analysis procedure.
General. Any structure may be analyzed using the dynamic lateral analysis procedures of Section 18.71.060. The equivalent lateral force procedure or the simplified analysis may be used for structures
conforming to the requirements on the use of those analyses.
Equivalent lateral force. The equivalent lateral force procedure of Section 18.71.070 may be used for regular structures or irregular structures having plan irregularity only of not more than four (4) stories.
Simplified analysis. Regular structures of not more than four (4) stories conforming to the requirements of Section 18.71.080 may be analyzed for a prescribed strength of their systems and elements.
E.
Alternative procedures.
General. Alternative lateral analysis procedures using rational analyses based on well-established principles of mechanics may be used in lieu of those prescribed in this chapter when approved by the Building Official.
Seismic isolation. Seismic isolation (Chapter 17 of ASCE 7-16, Seismic Design Requirements for Seismically Isolated Structures), energy dissipation and damping systems may be used to reduce story drift when approved by the Building Official. The isolated structure shall comply with the drift requirements of Section 18.71.060.
(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)
Get a plain-English answer with a citation back to this text.
Ask AI about this code