The maximum seismic load effect, Em, shall be used in the special seismic load combinations in Section 1605.4.
Where the effects of the seismic ground motion and gravity loads are additive, seismic load, Em, for use in Equation 16-19, shall be defined by Equation 16-52.
Where the effects of the seismic ground and gravity loads counteract, seismic load, Em, for use in Equation 16-20, shall be defined by Equation 16-53.
where
E, QE, SDS are as defined above and Ω0 is the system over strength factor as given in Table 1617.6.2.
The term 0QE need not exceed the maximum force that can be transferred to the element by the other elements of the lateral-force-resisting system.
Where allowable stress design methodologies are used with the special load combinations of Section 1605.4, design strengths are permitted to be determined using an allowable stress increase of 1.7 and a resistance factor, f, of 1.0. This increase shall not be combined with increases in allowable stresses or load combination reductions otherwise permitted by this code or the material reference standard except that combination with the duration of load increases in Chapter 23 is permitted.
Where the effects of the seismic ground motion and gravity loads are additive, seismic load, Em, for use in Equation 16-19, shall be defined by Equation 16-52.
Em= ΩQE + 0.2SDSD
(Equation 16-52)
Where the effects of the seismic ground and gravity loads counteract, seismic load, Em, for use in Equation 16-20, shall be defined by Equation 16-53.
Em= ΩQE - 0.2SDSD
(Equation 16-53)
where
E, QE, SDS are as defined above and Ω0 is the system over strength factor as given in Table 1617.6.2.
The term 0QE need not exceed the maximum force that can be transferred to the element by the other elements of the lateral-force-resisting system.
Where allowable stress design methodologies are used with the special load combinations of Section 1605.4, design strengths are permitted to be determined using an allowable stress increase of 1.7 and a resistance factor, f, of 1.0. This increase shall not be combined with increases in allowable stresses or load combination reductions otherwise permitted by this code or the material reference standard except that combination with the duration of load increases in Chapter 23 is permitted.