Advanced Materials Research Vols. 255-260

Abstract: Adhesively bonded carbon fiber reinforced polymer (CFRP) laminates to the steel structure is a new technology of structure reinforced, which has broad application prospects. Based on the experiment this paper adopt “3D Solid-Spring-Shell element” FE model to analyze how the facts such as the type of FRP ,steel plate and binder, CFRP’s width, steel plate’s thickness effect on the performances like the characteristics of stress distribution, the process of adhesive shear failure and damage characteristics.

Abstract: Through the finite element analysis software, fourteen strengthened beams are calculated in the condition of considering bonding-slip or not respectively. Comparing simulation results with test and theoretical calculation, We can draw the following conclusions: Testing reinforced concrete beams when there is no debonding, ANSYS simulation, theoretical calculations and experimental results agree well. Testing reinforced concrete beams when there is debonding. By considering the bond-slip calculation model calculation accuracy is higher. .Numerical results show that, prestressed CFRP with relative of prestressed girder of carbon fibre reinforced beam can significantly improve the cracking beam loading, and effectively improve the yield loads, but the ultimate load.

Abstract: Longmen Grottoes is the famous cultural heritage. Many factors should be considered in reinforcement project of the plank way cantilever beam. Considering the characteristics of the tourist area, many reinforcement schemes are put forward. At last, the methods with CFRP sheet is selected to reinforce the plank way cantilever beam. The reinforcement effect shows that the method with CFRP material increases very little weight of the structural members. The appearance of the reinforced member is harmonious to the surrounding environment.

Abstract: Considering the initial stress field and concrete damage, no-linearity caused by crack of concrete, non-linear of reinforcement, elastic-plastic of soil around pile, couple interaction between concrete and steel, non-linearity contact of interface between pile and soil, the lateral load bearing capacity of squeezed branch and plate pile under vertical and lateral load is studied with infinite element and finite element couple method. The results indicate that the vertical load decreases the lateral displacement of pile top and increase the pile lateral load bearing capacity at the same time.

Abstract: This paper presents flexural analysis of a GFRP bar reinforced concrete beam by using Finite Element Modeling (FEM) approach. The FEM model is developed using solid element for concrete and bar element for GFRP reinforcement. Results from FEM show good agreement with the reported experimental result under service loading, in terms of load vs. mid-span deflection. The first cracking load from FEM matches analytical solution fairly well, while ultimate flexural capacity of RC beam from FEM shows 8.3% higher than that calculated with ACI 440 Equation.

Abstract: In this paper, the tensile strength retention of GFRP bars embedded in moist concrete under sustained loads is discussed on the basis of reported data. Long-term performance of GFRP bar is predicted by a newly developed model through time-temperature shift and time extrapolation approaches. Results indicated that higher temperature and longer exposure time result in more tensile strength loss of the sustained GFRP bar in moist concrete. Above certain temperature, GFRP bar in moist concrete with about 20% sustained load fails in rupture of GFRP bar for 75-year design lifetime. The temperature effect shall be taken into account in the design codes/guidelines.

Abstract: Corroded RC columns do not possess necessary ductility to dissipate seismic energy during a major earthquake, the study investigates the use of hybrid fiber reinforced polymer (FRP) wrapping as a method of retrofitting non-ductile corroded RC columns, and a model to determine the envelope response of RC corroded columns strengthened with hybrid FRP are presented based on cross-section analysis for undamaged RC element. The results show that the technique of strengthening corroded RC column with hybrid FRP is quite effective, the envelope curve estimated using the linear plane assumption with modification by reinforcement slip model, may still be used as the envelope curve of RC corroded columns strengthened with hybrid FRP, a good agreement between analytical and experimental results is observed.

Abstract: The study on bond-slip performance at the interface of concrete frames-fiber plasterboard (CFFP) is very significant to perfect the theory of CFFP and the FEM analytical models. The pull-out experiment on eight CFFP from three series does research on the effect of concrete strength and the interface length on the interfacial bond strength of fiber plasterboard and core column concrete. The experiment of CFFP is well-designed to obtain the curve of bond-slip constitutive relationship.

Abstract: The characteristics and research situation of bond-slip performance at the inter face of concrete and other materials are introduced, and the bond-slip constitutive relation models are summarized at the same time. Through the load-slip curves obtained from the pull-out experiment of CFFP, the proposed bond-slip constitutive relation models are presenting, including the simple one. With the numerical simulation analysis of CFFP is carried out by the use of the proposed constitutive relation, while the numerical simulation results are in good agreement with the experimental results conducted before, which is feasible and can be applied to further research on CFFP.

Abstract: The cement mortar with glass fiber (GF) can be widely used in strengthen different structure elements. In general, discrete glass fiber was used for improving the tensile strength of mortar. In article, the optimum material contents (sand, cement, water and fiber) enhancement compression strength with tensile strength was investigated. Forty-two specimens are tested after 28 days. Each specimen has of 3 cubes 15*15*15 and the average results were taken into consideration. The mortar content is cement, sand, water and discrete glass fiber. The fiber lengths (L f) are 20, 35, 50 mm. the fiber contents ( Vf ) are 1.5%, 3.0% and 4.5%. The water cement ratios (W/C) are 0.47, 0.42, and 0.37. The cement sand ratios (C/S) are 1:2, 1:3 and 1:4. The results show that, b y reducing the C/S ratio, the discrete glass fiber used is not recommended using. Moreover, from the experimental studies, the curves required for awareness the mixed material of mortar with discrete glass fiber were plotted. The theoretical equation that can be used in the initial trial mixing design is determined. This type of mortar can be successfully used for repairing or strengthen brick wall, or replaced instant of steel mish for resistance change temperature between wall layers.