Advanced Materials Research Vols. 243-249

Abstract: Test of two specimens (four different joints) of steel secondary beam embedded in reinforced concrete girder in frame structure and one specimen with steel cantilever beam embedded in reinforced concrete girder under static load were conducted. The steel beam up-flange was pulled out because of the concrete cracks caused by the moment, shear and torsion at the upper zone of the concrete beam near the steel beam end. Shear failure of the concrete beam and the top flange pullout failure are the most hazardous failure modes. Lacking restraint of concrete and the reinforcement of steel bar in the concrete slab and catenary action of restraint steel beam, the capacity of steel cantilever beam is much smaller than other beams. Load-slip curve of top flange of steel beam, load-rotation curve of the steel beam end are obtained through experiment. Primary calculation method of joints flexural capacity related to section size of composite steel beam, embedded depth of steel beam, flange width of steel beam embedded end, height of frame girder, is put up with. Analytical results of ABAQUS are shown as follows. Top flange pullout failure of steel beam is caused by the detachment of concrete and steel beam end, and the warp of the concrete slab near the support plays an unfavorable action on the performance of the steel beam. The end rotational angle of the steel beam with anchor bar is smaller than that without. The steel beam with shear connectors develops a smaller rotational angle and a higher load capacity.

Abstract: Using the Equivalent Load Method of unbonded prestressed tendons reinforcement in cylindrical shell, and the concepts of influencing factors of pool wall boundary conditions for hydraulic or annular prestressed reinforcement, the way of unbounded prestressed tenons optimizing location is discussed. It is emphasized that the number of tenons in pool top wall is more than that of in pool bottom wall , and the optimum reinforcement ratio is only 1/3 ~ 1/4 of actual design reinforcement ratio.

Abstract: With the calculation methods for the sectional curvature ductility of reinforced concrete flexural components, analysis was conducted on the factors affecting the formation of plastic hinges at the ends of RC frame beams and their rotational capacities; on the basis of which, singly-doubly reinforced rectangular section method for flexural design calculation was put forth, which is favorable to the realization of beam hinge mechanism. The analysis of a practical design case shows that the method proposed is not only beneficial to the formation of plastic hinges at the beam ends and their rotational capacities, but also results in considerable reduction of longitudinal reinforcement, hence lowering of cost, ease of construction, so that it is worthy of popularization and application in design practice.

Abstract: The steel beam is strengthened by prestressed CFRP sheets, which can increase capacity, reduce distortion and improve the utilization of CFRP cloth. Through the adhesive layer, the CFRP sheets and steel beam work together. Therefore, the interface is the weak link components, the adhesive layer and the physical and mechanical properties of CFRP fabric is an important factor for interfacial shear stress. Based on the elastic theory, a prestressed CFRP cloth and steel interface shear stress differential equation is established, and a calculation formula for interface shear stress is given. The calculation results show that, along the steel beam, interfacial shear stress distribution of CFRP is found with non-uniform, which increases the fastest growing at the end, and grows with increase of initial prestress.

Abstract: The article proposes boring shaft lining used super strength steel fiber concrete and double steel cylinder to solve the problem of the construction of shaft lining in deep alluvium of 700~800m, and studies the mechanical characteristics and failure of the shaft lining structure based on the model testing. The studies indicates that boring shaft lining structure used super strength steel fiber concrete and double steel cylinder may greatly improve the capacity of the shaft lining, the ductility of common high strength concrete shaft lining, obtains good plastic characteristics and upgrades the reliability of the shaft lining structure. In addition, strengthening coefficient of super strength steel fiber concrete based on theoretical analysis and experimental results, providing the design references for the engineering application of the new type shaft lining structure.

Abstract: This paper presents the results of analytical studies on exposed type of column bases, which were carried out to investigate the effect of tensile force on cyclic behavior of column bases. The cyclic behavior of the column bases subjected to tensile force ratio n > -0.4 is stable. While, in the column bases subjected to tensile force ratio n < -0.6, the deformation of base columns progresses with increasing severely under a constant amplitude.

Abstract: A numerical study on slip effect of simply supported composite beams under negative bending moment is conducted by means of finite element program of ANSYS based on the feasibility verification of ANSYS. The research contents include: slip distribution rules; slip effect on deflection in service stage and ultimate bearing capacity; relationship between slip effect and shear connection、lognitudinal percentage of reinforcement and working behavior of composite beams with partial shear connection under negative bending moment .

Abstract: Mechanical properties of high-rise building on construction and on service life are different. Geometrical model of structure and material property are time-varying on construction, so mechanical property analysis of high-rise building on construction is complex. The software of ANSYS is selected as the analysis tool. Construction process of high-rise building is simulated through the element “life and death” function of ANSYS. Results of analog calculation are close to the actual values of structure because of considering the construction process. It is beneficial to the safety of high-rise building on construction.

Abstract: The behaviour of composite cellular floor beams is becoming important as such members are increasingly used in multistory buildings. But, in the design of some special cellular beam with sharp corner web holes such as eye-shaped openings, the issue of low cycle fatigue failure becomes increasingly critical. In this paper, three-dimensional nonlinear finite element models of composite cellular floor beams with eye-shaped openings have been developed, taking into consideration the influence of the changes in degree of shear connections. The assessment based on stress amplitude for risk of fatigue failure under low cycle service load is presented as design guides in this paper. It is concluded that the risk grows along with the increase of composite actions in beams.

Abstract: In the paper, the sandy pebble soil which was most massively distributed in Sichuan was used as foundation. The finite element model of mega frame structure including the superstructure, raft foundation and the sandy pebble groundwork was built by applying the finite element analysis software ANSYS. The response of the mega frame structures under dynamic load was analyzed to study the mechanical properties, deformational properties and the interaction between mega frame structures and the sandy pebble soil. At last, in the same structural style and same foundation soil, the dynamic behaviors of such structure which take no account of the interaction between mega frame structures and the sandy pebble soil was compared with structure which took account of the interaction. The research in the paper could provide certain reference value for the future engineering.