Advanced Materials Research Vols. 163-167

Abstract: Based on the reinforced concrete beam structure bonding with steel plate are consisted of different materials, the finite element model of the reinforced concrete beam structure bonding with steel plate was established using the whole model and the separated model respectively, the deformation, stress, strain and limit load of the reinforced concrete beam structure under the symmetrical concentrated load and the uniformly distributed load were studied using ANSYS. The research results show that the limit load value based on the finite element simulation is basically equal with the experimental value, there has little error between them, but within the scope of control in error, and the limit load under the uniformly distributed load is greater than the symmetrical concentrated load; The results from the whole model and the separated model are basically equal with the experimental results, which show that it’s feasible using the finite element simulation to analyze the reinforced concrete beam structure bonding with steel plate.

Abstract: According to the complex boundary condition of real bridge structure, appendix restraint parameters of structure boundary condition were detailed analyzed. The appendix horizontal and torsional restraint parameters were selected as research object. The least square constrained optimization inversion method was used to establish the question of reverse of bridge structure boundary appendix parameters based on tested and calculated mode parameters. The first order perturbation of eigen-value and eigen-vector based on matrix perturbation theory were substituted into the constrained optimization inversion equation, so the solving efficiency was improved greatly, and the iteration method was used to improve the precision. The corresponding program was made, and the example of a maglev railway girder shows that fairly well precise bridge structure boundary appendix parameters can be reserved with only former several modes parameters through four to seven times of iteration calculation.

Abstract: To accord with the requirements of large area soft foundation treatment project, did the construction field monitoring and detection test including surface subsidence, pore water pressure, deep horizontal displacement, cone penetration test, vane shear test, and so on, make an effective and timely assessment with the construction quality and the reinforcement effect of foundation treatment project.

Abstract: Using the method of sticking steel plates and CFRP, 2 R.C. cross-shaped columns are strengthened. One using steel pastes, another using complex strengthening by steel plates and CFRP. 2 strengthened columns and an unstrengthened column was carried out aseismic test. Study showed that pasting steel strengthening; carrying capacity of the cross-shaped column has been significantly improved; while the method of complex strengthening, carrying capacity and ductility of the cross-shaped column were significantly improved.

Abstract: Intermediate crack debonding is a common failure mode of reinforced concrete (RC) beam flexurally strengthened with externally bonded prestressed fiber reinforced polymer (FRP). This study analyzes the effects of flexural cracks and interface softening behavior on the interface shear stress of RC beam strengthened with prestressed FRP under three-point bending loads, and presents an analytical solution for the FRP axial force at the flexural crack section of the strengthened beam. By regarding the interface fracture energy as the debonding criterion, a new theoretical model to predict the debonding load-carrying capacity of RC beam strengthened with prestressed FRP is proposed.

Abstract: Three reinforced concrete (RC) beams strengthened by high-performance ferrocement and two control specimens without strengthened are investigated when RC beams have low compressive strength. Flexural behaviors of strengthened RC beams with high-performance ferrocement are evaluated based on comparative analysis with RC beams. The strengthening results of steel meshes with U-shape (i.e. ferrocements are put onto the tension face and two profile faces) are analyzed. The flexural capacity, deflection and crack width of RC flexural beams are measured, and then comparative analysis is carried out for deformation performance and law of crack development. The test results show that ferrocement contributes greatly to increase the flexural capacity and raise crack-resisting capacity. The experimental results can provide a theoretical reference for actual engineering designs.

Abstract: In this paper, with the methods of bonding steel, CFRP and complex strengthening, four R.C. T-shaped columns are reinforced. The experimental researches of the above four reinforced columns and one not reinforced in the low-cycle repeated loads are completed. Carrying capacity, energy dissipation, ductility and other characteristics of the T-shaped columns are studied. The results show that: the flexural bearing capacity of the T-shaped columns reinforced with bonded steel is substantially increased; the ductility of the T-shaped columns reinforced with CFRP is substantially increased too; the bearing capacity, ductility and energy dissipation of the T-shaped columns reinforced with complex method are increased synchronously.

Abstract: This paper presented the on-site test results on two-way RC slabs with and without FRP-strengthening. Two slabs strengthened with BFRP, one slab strengthened with CFRP and one slab without strengthening were tested on a practical engineering structure being repaired. The effects of different load cases on mid-span deflection, distribution of stresses around the steel bars at the top and bottom of slabs were analyzed.

Abstract: Based on pseudo-static test of rowlock wall with different constructional measures by MTS loading system, the position of initial crack, distribution of crack, cracking load, failure load, failure state are studied, in order to provide test basis for the determination of economical and effective construction measures for rowlock wall. The test results show that the cracking load and failure load of rowlock wall reinforced with constructional column and tie bar, or with constructional column and horizontal reinforced concrete band,were increased significantly compared with rowlock wall without reinforcement measure. The reinforced rowlock wall has better ductility, whereas rowlock walls without reinforcement measure show obvious brittleness.

Abstract: Because of High-resolution, high accuracy, rapid and efficient, Ground-penetrating radar has been widely used in engineering testing as one of non-destructive evaluation (NDE) methods. Combined with practical work, this paper introduced how to use the ground-penetrating radar in tunnel liner testing, the detection, preferences and waveform analysis, etc.