Applied Mechanics and Materials Vols. 351-352

Abstract: Steel bar defect detection in concrete is an important content of civil engineering structure detection. Currently there are no effective methods for nondestructive testing of steel bar defects . This paper studies the application of electromagnetic induction technology for Steel bar defect detection. Firstly, the principle of electromagnetic induction technology to detect rebar are described. Secondly,an air dielectric test device was designed and Steel bar defect in the device was detected by magnetic scanner. Through analyzing we got the characteristics of scanning images from different Steel bar defects. Thirdly this experimental result was compared with detection result in concrete.Finally verify the accuracy and feasibility of this method.

Abstract: For a better analysis of the deformation of the steelreinforced light aggregate concrete member, adopt asymmetric loading mode,carry on numerical simulation of bearing capacity of steel reinforced lightaggregate concrete beams. The simulation results show that the: In theasymmetric loads, longitudinal reinforcement of the bottom of the beam both ends of the constrained position, due tothe presence of constraints, make it tensile stress,in the 250mmposition is tensile stress minimum, compressive stress correspondingly larger.In the central beam downward bending deformation, this part of the lower edgeof the beam longitudinal reinforcement tensile stress.

Abstract: In order to study the influencing parameters of the shear lag effects on the box-girder beam, the effective width was analyzed by the ways of looking up the present code and formula. Taking the simply supported and cantilever girder as the example, the parameter sensitivity was studied, such as width/span, cantilever length and span. The results showed that the shear lag effect of mid-span beam is small but the support beam is outstanding; the fixed amount relationship of the parameters and the shear lag effects was put forward. The conclusions will be useful for the design and construction of the box girder bridge.

Abstract: Excessive prestress loss in Prestressed Concrete (PC for short) continuous beam bridges and continuous rigid frame bridges cause structures to be different types of diseases. Based on theoretical analysis and experiment , this paper points out the imperfection of the effective prestress formula in Curving Hole at present. According to the research on the influencing factor of prestressed loss in Curving Hole of friction coefficient, it plays a remarkable role on the analysis about the prestressed loss in Curving Hole of prestressed concrete structure.

Abstract: The moment and rotation curve (M-θ curve) of beam-column connection was described by three-parameters power model, but the shape coefficient (n) in the model rarely was studied. Eight top and seat angle connections was selected to analysis with Ansys10.0, based on three-parameters power model which was fit for structural analysis . The results were testified valid by test data and got others curves. The suggested value of shape coefficient (n) was got by numerical analysis method of these curves. The research indicated that numerical curves is fitted with test curves and FEA curves perfectly, and the shape coefficient (n) value of those numerical curves have small difference. By contrast of the initial stiffness and ultimate bending moment and those fitting curves, the shape coefficient (n) of top and seat angle connections is suggested 1.9.

Abstract: Two kinds of finite element model which can reflect the effects of different loading positions were constructed with Beam 188 and Shell 181. Effects of different restraints, load models and rise-span ratios on out-of-plane buckling were studied by comparing results of fixed arches with that of pin-end arches under three loading models. It is conservative to design by employing results of radial loading. As for out-of-plane stability, pin-end arches are better than fixed arches when rise-span ratio is big. Compared with U-section pin-end circular arches with diaphragm, those with batten plates have batter out-of-plane stability, and they are more economical and easier to construct.

Abstract: With the pseudo-static test of 4 concrete-filled square steel tubular column and steel beam joint with outer stiffened ring, this paper discusses the failure characteristics, failure mechanism and seismic behavior of joints under different axial compression ratio. The analysis of the testing results shows: when reached the ultimate strength, the strength degradation and stiffness degradation of joints are slowly and the ductility is also good, the energy dissipation capacity of joints is much better.

Abstract: This paper analyzes isolation questions of irregular structures, based on principles of structural isolation system. It also discusses present research and existing problems of translational torsion coupling isolated structures. Property parameters of layer unit are used to build up stiffness, mass and damping matrix of sway components, and dynamical calculation method of isolation system is explored when considering floor deformation. In this paper, the authors set up simplified calculation model for dynamic reaction of plane irregular buildings by using substructure method and taking floor as shear bending deep beam, quadratic displacement function and primary angle function are also used to describe floor movements. Time –history method is adopted to analyze dynamic responses of floor deformation for plane irregular buildings (T and U shapes).

Abstract: The calculations of the elastic modulus and the internal stresses of the orthogonal symmetric laminated plates are very difficult, so experimental or numerical simulation methods were used generally. This paper proposed an Equivalent Strain Model, which can greatly simplify the derivation process of the analytical formulas. By the Equivalent Strain Model, the elastic modulus formula of two-layer plate was derived, and the formula shows that the elastic modulus of the laminated plate meets to the mixture rule of the cross-sectional area ratio of each its single-layer plate; Other formulas derived show that the stress within each single-layer plate is proportional to its elastic modulus and the external load stress, and is inversely proportional to the elastic modulus of the laminated plate. The formula of the average shear stress between two single-layer plates also was derived. Recursive method can be used for multilayer plate calculations.

Abstract: Based on a real project, this paper presents the design of a space steel pipe truss with a triangular cross section upside down, in which it covers the selection of structure type, arrangement of the structure, loads and load combination, structural analysis as well as the detailing of some major joints. Thus it can serve as a reference for the design of similar large-span trusses.