Several seismic building codes such as Uniform Building Code (UBC), Standard Building Code (SBC) and BOCA have been adopted in various regions in the US Among these codes, the UBC is widely disseminated and recognized in the international engineering community. This chapter introduces UBC-94 and UBC-97 stipulate two basic lateral-force procedures for minimum seismic design: static lateral-force and dynamic-lateral force. For both UBCs, the average annual risk is 10% probability of being exceeded in any 50-year period. Structural and non-structural damages are anticipated which may not be acceptable for essential facilities, such as hospitals and communication centres. A higher-level design force is required to ensure their ability to function during and after an earthquake. UBC-94 stipulates two procedures to determine seismic forces for structural analysis: static lateral-force procedure; and dynamic lateral-force procedure including time-history analysis. Dynamic analysis of building structures can be performed by response spectrum analysis or time-history analysis.