Experimental Study on Mechanical Behavior of Prefabricated PEC Composite Beams Under Cyclic Loading

In this paper, a new type prefabricated partially encased composite beam (PEC beam) using screw arbors instead of stirrups or welded transverse links in ordinary PEC structures to connect the upper and lower steel flange has been proposed. It not only retains the performance advantages of PEC structures, but also greatly enhances the prefabricated degree of structure and simplifies construction process. Twelve beams with and without screw arbors were tested under cyclic loading to study the mechanical behavior of this new type of PEC beams. The major factors considered were shear span ratio (λ = 1.0, 2.0, 3.0 and 4.0), with or without screw arbors and concrete thickness. Test results including failure mode, load–deflection curves (P − Δ curves), characteristic points, ductility and stiffness were introduced and discussed in detail. The test results showed that the failure mode of PEC beams changed from shear failure to bending failure with the increase of shear span ratio, and the asymmetric damage of specimens can be improved by screw arbors. In addition, PEC beams with screw arbors have better ductility and slower stiffness degeneration than those without screw arbors. Potential application value can be seen from this new type of prefabricated PEC beams.