Dynamic Time History and Pushover Analysis of Special Truss Moment Frames by Using Eurocodes

Special Truss Moment Frames (STMFs)were introduced in USA (1994) as a new system alternative to ordinary Truss Moment Frames (TMF). STMFs are resistant to both gravity and lateral loads over long spans and AISC 341-10 has all the necessary design procedures. STMF design procedures are not available in Eurocodes. Therefore, the main objective of this research was to investigate STMF by using Eurocodes and European steel sections. A numerical study was undertaken to study the seismic behaviour of (STMFs) using dynamic time history and pushover analysis. Performance-based Plastic Design (PBPD) methodology was used to design the STMF based on Eurocode 8 and in some parts AISC 341-10 code was used. Seismostruct software was used to design frames with 4, 7 and 10 stories and to investigate parameters, such as, maximum base shear, drift story, capacity curve and also performance criteria (chord rotation) according to Eurocodes through extensive nonlinear dynamic analysis for an appropriate number of ground motion records. In second phase, a set of nonlinear static (pushover) analysis carried out to find the capacity curve, base shear and story drifts. In the third phase, SAP2000 was used to find performance limit state of STMF and TMF and the results were compared together. In fourth phase, the behaviour factor of STMFs was calculated and compared with the behaviour factor of other structural framing systems. The results obtained were compared with the results of similar frames from past literature. Overall, the results confirmed the validity of the proposed framing system by meeting all the performance design objectives, such as, target drifts and intended yield mechanism. Generally, nonlinear analysis do not required the structural performance check after PBPD and this can be considered as an advantage. Keywords: STMF, PBPD, Dynamic time history, pushover, performance criteria