Applied Mechanics and Materials Vols. 351-352

Abstract: Considering the true mechanical states of roller compacted gravity and arch dams, the strength experiments of the roller compacted concrete (RCC) specimens with two graded-aggregates made from a high arch dam are carried out. These specimens are of three kinds: body specimens, layer-treated specimens and layer-untreated specimens and the tests include direct shear and triaxial compressive-compressive-shear, tensile-compressive-shear tests. The shear strength of three kinds of specimens under different stress states is analyzed systematically. By regression of the tests results, respective failure criterions for RCC under different combined loads are proposed.

Abstract: The failure of elastic perfect cylinders under uniform external pressure is caused by circumferential buckling. The effects of the cylinder length, of the restraining conditions at boundaries and of the length of the pressurized zone all have great influences on the critical buckling load. In the European Standard for Shells EN 1993-1-6 (2007), the critical circumferential buckling stress is obtained by introducing an external buckling factor which takes the influence of different boundary conditions into account. However, the restraint of the meridional rotation at boundaries was not considered separately for the factor. For short cylinders, any restraint of the boundaries affects the buckling mode and buckling strength greatly. In this paper, the effect of meridional end rotations on the buckling strength of short cylinders was studied. The pre-buckling membrane stress state given by membrane theory was assumed for all the analyses.

Abstract: According to the requirements of fire scientific theory and the fire resistance design of structures, and combined with the practical engineering and based on the building damage situations that may occur, this paper analyzes the characteristics of mechanical behavior of prestressed steel column in high temperature condition (fire). It puts forward that how to consider the effects of high temperature parameters and prestressed loss on the structural bearing capacity in prestressing steel column design, and may provide reference values for the fire resistance design of steel structures.

Abstract: The bored piles are widely used in engineering, but also a lack of understanding of the mechanical mechanism of post-grouting technology, design and calculations based on the experience. Using FLAC3D finite element software, analyzing from axial force, pile lateral friction, pile end resistance to improve the carrying performance. Simulation data and field test QS curves is almost consistent, verifying that the model is correct. Contrasting between the not-grouting pile and grouting pile, finding that the limit lateral friction and end resistance of grouting pile have significantly increased in the maximum loads.

Abstract: Experiments of two graded-aggregates concrete used for RCC arch dam are conducted. The experiment includes three states: direct shear state, compressive-compressive-shear state and tensile-compressive-shear state. Comparison and analysis of the deformation characteristics of body specimens and layer specimens are carried out. Influences of different stress states on body specimens and layer specimens are also studied in this paper.

Abstract: According to the requirements of fire science theory and structural fire resistance design, and the situation of possible disasters that may occur in the building based on practical project, this paper analyzes the mechanical characteristics of prestressed steel beam under high temperature (fire) circumstances. It puts forward how to consider the effects of parameters of different steel categories, the magnitude of prestress tension control forces and prestressed loss of steel cables on the structural bearing capacity in prestressed steel beam design, which can provide references for the fire resistance design of prestressed steel structures.

Abstract: Based on the analysis for 10 series (altogether 50) of finite element analytic models, the time-history analysis is discussed in this paper to investigate the relations between frame parameters of semi-rigid steel frames, these parameters include the frame's floor number, the frame's span number, especially the rotation stiffness of beam-to-column connections. Comparing with the steel frame structure, the ductility of semi-rigid steel frame structure is improved with the reduction in the rotation stiffness of connections. Furthermore, semi-rigid steel frame structure under seismic loads has a good seismic performance.

Abstract: This paper provides a brief introduction of endochronic damage constitutive model and studies the application of endochronic damage constitutive model in cracking analysis of mass concrete. This paper proved the model is feasible in cracking analysis of mass concrete and it is worth deep study.

Abstract: Structural damage detection using vibration modes has become a very important research area in recent years. In this paper, an improved generalized flexibility sensitivity method is presented for structural damage identification. The existing generalized flexibility method is firstly reviewed and then an improved technique is proposed. In this contribution, a simple accelerated formula is developed to improve the accuracy of the generalized flexibility method. With the introduction of the accelerated formula, the proposed method is able to achieve more accurate results than that obtained by the original generalized flexibility method without any high-order analysis or multi-iterations. The effectiveness of the proposed method is illustrated using simulated data on a published numerical example. From the numerical results, it can be conclued that the proposed new method is very efficient with only the first frequency and its corresponding mode shape. It has been shown that the proposed procedure is simple to implement and may be useful for structural damage identification.

Abstract: This article summarized seismic design method of high-rise building from seismic fortification goal, use of materials, structural systems, analysis methods and trends. Then it discussed the structural design significance of high-rise buildings to achieve sustainable development. Lightweight quality, high strength material, diversity type, spatial component, braced lateral force resisting system, structuring combination and shock absorption building are the trends of high-rise building development.