Advanced Materials Research Vols. 368-373

Abstract: Experimental researches of one 1:6 scale steel truss reinforced concrete (STRC) transfer beam were carried out to investigate mechanical performances of a transfer beam under vertical loads in an actual tall building. The development of crack along the beam, strains of reinforcements and steel truss, and the force transference mechanism of the deep beam were analyzed. Experimental results showed that the bearing capacity and rigidity of the STRC transfer beam are significantly enhanced compared with normal RC transfer beam. The strut-and-tie force transference mechanism is formed in the STRC transfer beam and fully made use of by the STRC transfer beam. And results verified that the shortest and most direct force transference path can be achieved to transfer upper loads.

Abstract: The numerical simulation on buckling test copper pipe is carried out with dynamic finite element software LS-DYNA. The results clearly reflect deformation, stress, and strain of copper pipe in different moment. This method overcomes the weaknesses and shortcomings of experimental analysis, which provides a new method for buckling analysis of under the action of axial impact loading.

Abstract: Reinforced concrete cover in the road culvert cover design, in order to facilitate the construction, usually using precast reinforced concrete solid slab, but the overall cost is not low. This article researched a reinforced concrete multi-ribbed hollow composite slab, it based on the theory of reinforced concrete multi-ribbed slab structures, using a precast reinforced concrete ribbed slab as the bottom die, then poured reinforced concrete beams and panels rib ,and them constituted a whole stack of reinforced concrete ribbed hollow slab. This kind of cover, compared with the precast reinforced concrete solid cover, is not only good mechanical properties, high integrity, but also saving concrete, steel, and bottom slab appeared smooth and fine, lower construction cost.

Abstract: The earth pressure behind the abutment of integral abutment bridge was measured in practice. The distribution and variation laws of the earth pressure are analyzed in seasonal falling and rising temperature difference through the test data. At the same time, the mathematical model of the coefficient of passive earth pressure when temperature rising under different ratio of the superstructure deformation and the height of abutment is established. Based on the mathematical model, the calculation value of the earth pressure behind the abutment in rising temperature difference is mainly agreement with the measured value

Abstract: In recent years, on the one hand destructive earthquakes frequently occur, and vibration control devices such as dampers and isolation become increasingly application in actual large-scale structures, on the other hand modern structures with complex styles and diversified materials possess significant non-proportional damping characteristics, and traditional methods based on Rayleigh damping assumption no longer meet seismic calculation requirement. According to this situation, firstly multiple degree of freedom modal equation and pseudo excitation method are both utilized to establish a new efficient calculation method system which is suitable for stochastic analysis of non-proportionally damped structure, and the new method can achieve adjustive calculation efficiency and accuracy. Furthermore, advantages and features of established method are analyzed, and guidance suggestions for appropriate method use are also proposed. Finally, numerical study is carried out to verify conclusions proposed by theoretical derivation, and efficiency and accuracy of established method system used in stochastic response calculation of non-proportionally damped structure is confirmed.

Abstract: A novel hydroxyapatite/chitosan composite plate enhanced by polylactic acid fiber is prepared via in–situ hybridization in the semipermeable mold. The influence factors of the composites are evaluated by orthogonal test; FT–IR, XRD and SEM are also used to determine the relevance between the composition and performance. Analyses show that: hydroxyapatite with weak crystalline state is generated in the composites; there is hydrogen bonding associating existing in the complex system; preferable interface junction is created between the fiber and hydroxyapatite /chitosan matrix, which is able to play benign potentiation to the mechanical strength. Orthogonal test finds that the pecking order of the influencing factors to physical properties is: fiber content > fiber length > hydroxyapatite content. HA/CS composite plate enhanced by PLA–fiber can get a significantly increase on flexural strength and bending modulus, therefore, it will be a kind of potential orthopaedic materials which possesses the ability of completely degraded.

Abstract: The sintering behavior of B₄C can be significantly affected by the additions of Si. The B4C based ceramics are prepared via hot pressing. The mixtures that contained initially 15wt% Si sintered at 1830°C for 0.5h, 98.7% relative density reched. The composition and microstructure of the composites are characterized by means of XRD and SEM. Some reactions occurred during the sintering of the two powders. The products are B4C, SiB6, SiC and B sub>12.97 Si.₀₃ C₂ when B₄C+15wt%Si eutectic composite sintered at 1830°C for 0.5h. The Flexural Strength and Fracture Toughness of composites reached 447.2MP and 4.62 MPa•m sup>1/2 highly be improved respectively.

Abstract: Based on the experiment, the splitting tensile strength and axial tensile strength of specified density steel fiber concrete are studied. The influence of type of steel fiber, volume content of the fiber and substitution ratio of lightweight aggregate is analyzed. The relationship between splitting tensile strength and axial tensile strength of specified density steel fiber concrete is suggested.

Abstract: With the growing global energy crisis, development of economic and land-efficient construction structural system became an significant subject in Civil Engineering field. Under this context, material and structural test and theoretical analysis research is meaningful on new energy-saving building material, glazed hollow bead insulation concrete. In this paper, one mix design that meet insulation requirements of the energy-saving project on coefficient of heat conductivity and compressive strength have been chosen. Under the uniaxial status, prism samples of above mix design have been selected to do compression strength and deformation tests; Systemic analysis of the relationship between the strength and deformation for glazed hollow bead insulation concrete has been carried through, and some results have been provided, including the stress-strain constitutive relationship of glazed hollow bead insulation concrete with grade c25, prism compressive strength, strain, initial elastic modulus, residual strength, ductility, etc.

Abstract: A finite element (FE) model of hexagonal honeycomb cores (HHCs) with single or double cell walls is framed based on the honeycomb cell array, to reproduce the compressive behavior under the quasi-static out-of-plane compression. The FE calculated deformation modes, deformation curves and values of quasi-static plateau stresses are presented in the forms of diagrams, compressive force-displacement curves and data tables, which are consistent with the existing experimental and theoretical calculated results. It is shown that the proposed FE analysis methodology is reliable.