In
this paper, the Eurocode 8 design approaches for concentrically-braced steel
frames are assessed against the results of shake table tests on a set of single
storey braced frames and a series of correlative nonlinear analyses. The test
programme investigated the influence of brace slenderness on the stiffness,
resistance and ductility displayed by the frame under earthquake loading.
Several sources of member and frame overstrength, which play an important role
in seismic performance and design, are identified. The tension-based design
approach largely adopted in design is examined together with the member
slenderness limits imposed on the bracing members. It is observed that the
bracing members with slenderness exceeding the codified limits demonstrated
generally satisfactory performance. The results of nonlinear time-history and
push-over analyses are observed to agree well with the experimental results,
especially with respect to brace tension forces and frame base shear. These are
used to support conclusions drawn from the test results.