Research For Mechanical Properties Of Prestressed Deep Concrete Flexural Member

Deep flexural member is refers to the reinforced concrete single beam and multi-span continuous beam which span-depth ratio l0/h≤5.0.Taking the prestress into deep flexural member can increase the component’s stiffness and crack resistance, effectively control the section size and reduce structure weight. A series of research achievements have obtained in the world at present, but the domestic study of prestressed concrete deep flexural member is still blank. In order to conduct the research of prestressed concrete deep flexural member, this article mainly conducts a study from the following works:In order to conduct the research of span-depth ratio to deep flexural member’s mechanical behavior,8 prestressed concrete deep flexural models were built by the software of ABAQUS to analyze the capacity, deformation, concrete and steel bar stress, crack and ductility, the results were as follows:with the same prestress the prestressed deep flexural member’s had 3 failure modes:the shear failure, the oblique section bending failure and the moderate reinforced beam failture. When the span-depth ratio is small, the prestress concrete deep flexural members has a internal force redistribution phenomenon, the mechanical model of "arch" forms; with the increase of pan-depth ratio,the prestressed concrete deep flexural member’s mechanical behavior is gradually close to the prestressed ordinary concrete beam.In order to conduct the research of prestressed Linear to deep flexural member’s mechanical behavior, two groups of prestressed concrete deep flexural model were built,one group’s span-depth ratio is 2,the other one is 5,the results showed:in contrasted with the prestressed deep flexural member of linear type prestressing tendon,the cruve prestressing tendon has little effcet on the prestressed deep flexural member; and for the prestressed deep beam of span-depth ratio 2, with the increase of prestressing tendon curvature, the ultimate bearing capacity increase slightly, and the mechanical behavior is good; for the prestressed short beam of span-depth ratio 5,the change of prestressed linear has little effect on the prestressed short beam’s failure mode, capacity and Stiffness.In order to conduct the research of Prestress degree to deep flexural member’s mechanical behavior, two groups of prestressed concrete deep flexural model were built, one group’s span-depth ratio is 2,the other one is 5, the results showed:for the prestressed deep beam of span-depth ratio 2, with the increase of prestress degree, the prestressed deep flexural member’s failure mode turn from bending failure to shear failure,when beyond a limited value,local pressure failure easily occurs; for the prestressed short beam of span-depth ratio 5, the increase of prestress degree has little effect on the prestressed short beam’s failure mode,the capacity, deformation and ductility increased.