An Experimental Investigation into the Behavior of Steel-Timber Composite Beams

An experimental study on the structural behavior of steel-timber composite beams is presented in this paper. The timber beams were reinforced with flat and channel-shaped cold form steel (CFS) sections through different types of shear connectors (bolts, self-drilling screws, and epoxy glue). A total of nine beam specimens were tested under monotonic loading. The performance of the strengthened beams was evaluated on the basis of ultimate load-carrying capacity, flexural rigidity, energy ductility, and strength-to-weight ratios. The strengthening of beams with CFS sections delayed or prevented the typical brittle failure as observed in control beams. Among different types of shear connectors, epoxy glue proved to be the most reliable connection for the composite beam, whereas bolts were the least efficient. The use of channel sections leads to a considerable enhancement in the load-carrying capacity of the timber specimens by various mechanisms owing to synergetic effects between CFS and timber. Relative to the control beam, an appreciable improvement in structural efficiency and ductility index was observed for all the strengthened beams.