B2Loads and load combinations

Where the required strength defined in these Provisions refers to the capacity-limited seismic load, the capacity-limited horizontal seismic load effect, $E_{c l}$, shall be determined in accordance with these Provisions, substituted for the horizontal seismic load effect including overstrength, $E_{m h}$, and applied as prescribed by the load combinations in the applicable building code.

Where the required strength defined in these Provisions refers to the overstrength seismic load, $E_{m h}$ shall be determined using the overstrength factor, $\Omega_{0}$, and applied as prescribed by the load combinations in the applicable building code. Where the required strength refers to the overstrength seismic load, it is permitted to use the capacity-limited seismic load instead.

User Note: The seismic load effect including overstrength is defined in ASCE/ SEI 7, Section 12.4.3. In ASCE/SEI 7, Section 12.4.3.1, $E_{m h}$ is determined using Equation 12.4-7: $E_{m h}=\Omega_{0} Q E . E_{m h}$ need not be taken larger than $E_{c l}$. Therefore, where these Provisions refer to capacity-limited seismic load, it is intended that $E_{c l}$ replace $E_{m h}$ as specified in ASCE/SEI 7, Section 12.4.3.2, and use of ASCE/ SEI 7, Equation 12.4-7, is not permitted. However, where these Provisions refer to the overstrength seismic load, $E_{m h}$ is permitted to be taken as calculated in ASCE/ SEI 7, Equation 12.4-7, with a maximum value of $E_{m h}$ equal to $E_{c l}$.