Research On Experiment Of Concrete Torsion Menber Strengthened By CFRP

Repairing and strengthening concrete structures with Carbon Fiber Reinforced Polymer (CFRP) is now a new technique popularized in the domestic civil field of structure rehabilitation. Because of its high performance such as light weight, high strength, simple procedures of construction and its good anti-decay property, CFRP is being used extensively in international and domestic civil engineering. Members subjected to various load types are becoming one of the most attractive research topics in recent years, but among which study of strengthening torsion members lacks of thorough research because of the complicated mechanism.In this paper , experimental research on the torsional behavior of 10 concrete torsion members reinforced with CFRPS and one member was carried out. The size of each member was 240mm×150mm×1200mm. In the test, many factors were considered, such as method of strengthening, the quantity of CFRPS, layer number of CFRPS, anchorage way, whether or not being secondarily loading .The theory of failure and type of failure of the strengthened girders were analyzed and simple and practical design method was proposed.The experimental results indicate that after reinforced, the ultimate bearing capacity and stiffness of specimen were improved, and the width of cracks become smaller. On the basis of experiment study, the mechanical model of RC torsion members strengthened by CFRP is presented with respect to mutative angle spatial truss model theory of inclined compression field considering concrete softening, and ultimate loading capacity of strengthening torsion members are derived . On the basis of calculation formula of torsion members described in code for design of concrete structures, the modified formula of strengthened torsion members of rectangular section are put forward together with the design and construction suggestions.