Study On The Flexural Behavior Of Reinforced Concrete Beams Using Steel Plate And Concrete Composite Strengthening Technique

Steel Plate and Concrete Composite Strengthening (SPCCS) is a new technique based on Steel Plate and Concrete Composite (SPCC) beams. It is an effective combination of bonded steel plate method and RC&PC strengthening method. In order to study the influence of design parameters, including planting rebar spacing and the space between studs and damaged extents, four rectangular beams and four T beams using SPCCS technique were tested. The applied load, deflection, strains and crack initiation and propagation regular were measured. The theoretical failure modes of SPCCS beams include mainly as follows:(1) Flexural failure, (2) Brittle debonding failure, (3) Over-reinforced failure, (4) Shear failure, (5) Flexural failure of sloping section. The actual failure modes of two rectangle beams are flexural failure and the others are brittle debonding failure.Test results showed that:(1) SPCCS technique highly improved ultimate bending capacity and flexural rigidity, (2) Ultimate bending capacity reduces with the increase of planting rebar spacing. (3) Larger the shear span ratio, less possibility of brittle debonding failure. (4) Flexural behavior was analyzed by the finite element software ANSYS, and the model can simulate SPCCS beams in flexural failure mode but not brittle debonding failure mode. (5) The ultimate bending capacity can be calculated by plastic method and simplified theoretical functions were proposed. Theoretical results agree with test results in flexural failure mode well while brittle debonding failure mode not. Considering the influence of the secondary force,the technique can be widely used in structure strengthening,and a design and application guide of SPCCS technique was proposed.