The Application of Load Combinations in Ground-Structure Interaction Software - NAT2024

Tunnels and other underground structures are typically designed using ground-structure interaction models instead of traditional structural analysis programs. This allows for the degree of load sharing 􀁅etween the two 􀁅odies to 􀁅e calculated􀀏 allowing for a more ef􀂿cient design. 􀀺hile modern codes outline the use of limit states with factors on applied actions, limit states are not typically compatible with ground-structure interaction models. Consequently, the engineer is left to develop rational methods for incorporating load factors into their analyses. Several methods can be considered, including the Largest Factor Method, Averaging Method, Subtraction Method, and Split Factor Method. This paper discusses the approaches, compares their effects using a case example, and provides a recommendation for designers.