The roof diaphragm of single-storey steel structures experiences in-plane shear and flexural deformations that add to the lateral deformations of the vertical bracing system. The in-plane flexibility of the diaphragm may also lengthen the building period compared to structures with rigid diaphragms. This paper describes a field test program performed on a typical single-storey steel braced frame building located in Montreal, Canada. Measurements were taken under three conditions: ambient vibration, forced vibration and pull & release testing. The impact of removing bracing members in a braced bay located at mid-length of the building was also examined. Numerical models of the structure accounting for the flexibility of the roof diaphragm were used to predict the periods. The results show that the amplitude of excitation influences the period of the structure. The numerical predictions agreed with the high amplitude period measurements.
展开▼
