ASCE 7/IBC Wind and Seismic Load Combinations - CAESAR II - Help

The ASCE 7 standard provides two design methods:

• Load and Resistance Factor Design (LRFD) compares required strength to actual strengths. LRFD provides the actual response of the system, including deflections and loads on supports and structure, when the actual wind or seismic load is applied.

• Allowable Stress Design (ASD) compares actual and allowable stresses. ASD uses load reduction factors (0.7 for seismic events and 0.6 for wind events) when calculating stresses.

CAESAR II uses ASD to evaluate a piping system under wind and seismic loads. To comply with ASCE 7 requirements, you must include the load reduction factors in your load cases for stress compliance.

IBC refers to ASCE 7 for wind and seismic loads.

The following table provides example load combinations showing the use of ASCE 7 load reduction factors (in bold).

In CAESAR II 2019 (version 11) and later, the Seismic Wizard no longer includes the 0.7 reduction factor for consistency with wind loads, which never included the 0.6 reduction factor.