Experimental Study On Shear Performance And Design Methods Of Partially Prefabricated Steel Reinforced Concrete(PPSRC) Beam

Partially prefabricated steel reinforced concrete beam(PPSRC beam)is an innovative steel reinforced concrete(SRC)composite beam.The PPSRC beam is based on traditional SRC beam and composed of prefabricated high-strength concrete outer-shell and cast-in-place inner-part.Compared with SRC beams,PPSRC beams have enough shear capacities and advantages in flexible design,convenient construction,low cost,and better construction quality.Compared with traditional reinforced concrete beams,PPSRC beams have enough shear capacities as well as high bearing capacity,high stiffness,good seismic performance.Thus,the PPSRC beams will be widely used in the future.The shear performance of PPSRC beam is rarely studied around the world.In order to investigate the actual shear performance of PPSRC beam,10 full-scaled beam specimens were studied in this thesis,including 2 PPSRC beam specimens with rectangular section shape,4 PPSRC T-beam specimens and 4 PPSRC inverted T-beam specimens.The failure processes,failure patterns,cracking modes,and shear capacities of all beams specimens were thoroughly analyzed to investigate the effects of shear span ratio,section shape and loading mode.On the basis of experimental results,it could be concluded that the shear performances of the PPSRC beams under sagging and hogging bending moment were relatively good,and all PPSRC beam specimens were fully composite because no obvious slippage on the interfaces between the steel shape and concrete or between the precast concrete and the fresh concrete was observed.In this thesis,based on the truss-arch model and superposition method,the shearmechanism of PPSRC beam was analyzed,and a set of calculation formulas of shear capacity of PPSRC beam under sagging and hogging bending moment was established.Compared with now-existing calculation methods in specifications,it could be concluded that the results calculated by the formulas in specifications were conservative,and the proposed methods based on the truss-arch model and superposition method were verified to be valid by the comparisons between the experimental and calculated results.All the above research will be very helpful for the application of this innovative composite beams.