Experimental Investigation Of Bending Behaviour Of The Reinforcement Concrete T-shape Beams Strengthening By Steel Plate And Concrete Composite

The reinforcement of existing concrete bridges using steel plate and concrete composite ( SPCCS ) is a new method based on the theories of steel and concrete composite girders, which is an effective combination of enlarged section and steel-stick reinforced method, because it not only hold the advantages of both methods, but also avoiding their inherent defects. Thus, this serves as an innovative and a developmental reinforcing method.Coincident with the advancement of not reducing headroom under the original bridges and not repairing surface evenness of the structures, the composite strengthening can significantly improve the flexural limit load capacity, stiffness, collision-proof capacity of the existing concrete bridges, and restrict the development of cracks. Additionally, it also has an aesthetic effect. The steel plate and concrete composite technology pouring into the current society as a fashion are appealed to growing individuals. Thus, the reinforcement technology can be more effectively applied in practical engineering, which has a resplendent future.At present, the relevant research about SPCCS is rare in international level. To study its bending behaviour in static, two SPCCS beams which suffered from specimens experimental study on damaged concrete T-beam bridge systems were tested and the numerical analyze was conducted. By comparison between experimental and numerical result, the bending behaviour of SPCCS beams was analyzed thoroughly. The experiments of rectangular cross section beams and T-shaped cross section beams are considered with this technique have verified its feasibility, and the every capability of this SPCCS beam technology has been studied roundly, and the theory of design and analysis has been constituted. It was applied in practice successfully at last. Now the following research taskswere conducted in this thesis:1. Two SPCCS beams which suffered from specimens experimental study on damaged concrete T-beam bridge systems were tested to evaluate their bending capacity. The content included the design and fabrication of specimens, the distribution of tested points, and the procedure of the test. Then, the test results were analyzed to evaluate the bending capacity, deformation and strain.2. The theatrical analyze about the behaviour of SPCCS beam was conducted according to the results of experiment and correlative international studies. The bond characteristic, failure mechanism and shear strength computation of two interfaces was studied, the two interfaces which one between new and old concrete and the other between strength steel plate and new concrete. The practical formula of interface shear strength is proposed. By the practical formula proposed, the interface ultimate shear capacity and shear strength could be computed and evaluated. Then the simplified bending formula was supplied and it can be illustrated that the calculation is in good accordance with the test.3. The finite element software ANASYS was used for a numerical study of the specimen. Based on the linear static calculation, the dimension of the specimen was determined. Then, the dimension was checked by calculation considering material nonlinear. The finite elemental result could be the reference for design and computation of strengthening structural members by SPCCS method.4. Through the experiment and numerical analysis of the bending capacity of SPCCS, the characters of bending failure were obtained. On the basis of the result from experiment and finite element, the provisions concerning the design of such innovative composite girder were proposed.