Advanced Materials Research Vols. 163-167

Abstract: The temperature field analysis method of steel tubes reinforced columns under fire by finite element analysis software ABAQUS is proposed in this paper. The theoretical method is validated by tests, and the calculated results agree well with those of tests. On the basis of that, the influencing laws of section perimeter; steel reinforcement ratio and sectional core area ratio on temperature field are discussed. It has been found that the effects of section size and sectional core area ratio on temperature field are significant, but steel ratio has very little effect on temperature both of steel tube and of sectional center. These achievements make it possible to study further theoretical study on the fire resistance of steel tube reinforced concrete columns.

Abstract: It is well-known that in modern through and half-through arch bridges the suspenders are important components since they connect the bridge deck and the arch ribs. The collapse of bridge deck or arch ribs may be induced once one or more suspenders are broken. In this paper, the traditional design way of the suspenders in through and half-through arch bridges is discussed first. Based on the discussion, a new way to design suspenders for arch bridges is then put forward. The reasonability and robustness of this new way is proved by a numerical example based on a real through arch bridge using the comprehensive commercial software ANSYS. It can be concluded from the analysis in this paper that the new way to design the suspenders for the through and half-through arch bridges can assure the safety of the bridge effectively even though one or more suspenders happen to break.

Abstract: An attempt is made to extend the double superposition hypothesis for elastic laminate analysis to piezoelectric laminate structure analysis. In addition to the displacement, the double superposition technique is also applied to the electric potential. The double-superposition hypothesis for piezoelectric laminate analysis can predict the zigzag feature of the field variables along the transverse direction in piezoelectric laminates. Moreover, the elastic field computational cost of double superposition assumption is no more than that of high-order shear theories for global coordinates, and the degrees of freedom by double superposition assumption for electric potential are much fewer than those by layerwise models for electric potential. It will be seen from the numerical examples that the good accuracy and lower computational cost can be presented by the double-superposition assumption for piezoelectric laminate beams.

Abstract: The ultimate load-bearing capacities of axially-loaded steel tube composite column filled with steel reinforced concrete under three-dimensional stress based on the unified strength theory are analyzed in this paper. The influence of thickness-length ratio and scale effect are considered by introducing the reduction factor of equivalent constraints and concrete strength reduction factor, respectively. The nonlinear three-dimensional finite element analysis of the steel tube composite column filled with steel reinforced concrete is performed by the finite element software ANSYS. The numerical and the analytical results are compared with experimental results and good agreement can be observed. A series of numerical simulation technologies is studied and described in detail, such as selecting element type, defining material model of steel and concrete, establishing global finite element model with discrete reinforced bars elements, applying loads to the specimens, and setting solution controls option. The results indicate that ANSYS finite element software may well simulate the behavior of the steel tube composite column filled with steel reinforced concrete under axial compression through reasonably selecting parameters.

Abstract: Corrugated steel plate and surrounding soils are working together to share the load in buried corrugated steel structures. It is complicated to consider the structure-soil interaction, so the finite element method has already become the chief means of complicated structure analysis. Based on a practical project, considering structure-soil interaction, by using the finite element program of ANSYS, the paper set up a 2-D FE model and analyzed the soil pressure, the structural deformation and the internal force under different load conditions in detail. The analysis shows that structure-soil interaction has brought about stresses redistribution of surrounding soils, and adverse effects of soil pressure and displacement were limited. The variation range of soil pressure on the crown of arch increases with the load increases and the peak value of soil pressure approach to the code value and a rebound appears in the vehicle load range. The tendencies of vertical soil displacement are nearly the same to different load conditions, and the peak value of moments has an obvious change and can be influenced greatly by deflective load.

Abstract: Through the axial compression tests of two ordinary concrete-filled square steel tubular(CFSST) short columns and six composite CFSST short columns, the influence laws of section types, confinement coefficient, steel ratio and concrete strength on the mechanical behavior of the CFSST short columns were studied. The results show that in CFSST columns, the change of steel tube’s section form can improve effectively the cooperative work ability between the steel tube and core concrete, enhance the restraint effect of the steel tube on the core concrete, delay or inhibit the development of inclined cracks in the core concrete, increase the ductility and improve significantly the ultimate bearing capacity when the steel ratio or confinement coefficient is close to each other. With the increment of the confinement coefficient and steel ratio, the bearing capacity and ductility improve.

Abstract: Beam string structure (BSS), which is a new kind of semi-rigid hybrid system, composed of arch, strut and string, has been developed rapidly in long-span steel structures in recent years. Based on the principle of virtual work and Updated Lagrange, the formulas of geometric nonlinear F.E.M. for spatial beam element, cable element and truss element are derived respectively in this paper. Taking the one-way BSS model of the steel roof in Guangzhou International Convention and Exhibition Center as a computational example by using both linear and nonlinear analysis method, the analytical results show that it is appropriate when adopting the straight truss element with two joints and equivalent elastic modulus to simulate the cable element with small sag. Although the linear analysis can meet the requirement of practical engineering due to its weak nonlinearity of BSS, the nonlinear method is also important to improve the precision theoretically. The conclusions obtained may be helpful for the designers in similar projects.

Abstract: Based on Miyamoto’s method, the natural frequency of prestressed box girder with corrugated steel webs considering the impact of external tendons was obtained. And the result was modified based on the finite element model. It shows that: the external tendons will reduce the natural frequency of bridge with reduced range of about 3%. Beneficial references were provided to the layout of external tendons in order to avoid the resonance between the box girder with corrugated steel webs and the external tendons.

Abstract: PBL shear connector is a recently developed shear connector for steel-concrete composite structure that making the two element work as a unique piece. In this work, model test has been carried out to investigate the mechanical characteristics of 21 specimens in 7 types of PBL connectors. Combining the model test with finite element simulation, the main work has been done as follows：Load transfer behavior, load-slippage rule and static load mechanical property of PBL have been analyzed. Research on main factors that could influence the mechanical characteristic of PBL has also been conducted. Based on comparison of results of model test and finite element analysis, the feasibility of push-out simulation by nonlinear FEM has been analyzed. Compared to typical push-out tests results in mainland China, recommendations of push-out test of PBL are presented.

Abstract: To protect cultural relics,sliding response of free-standing museum cultural relic under earthquakes was studied by SIMULINK technique.By hypothesis that shape of cultural relic was rectangle, under earthquakes its sliding conditions were analysed,its motion equations were deduced, its response curves of displacement,velocity and acceleration were obtained,and parameters such as friction ratio between it and its base as well as peak earthquake acceleration values were discussed.Results show that slide motion of cultural relic relates mainly to friction ratio and earthquake strength;Its sliding response is more obvious with the increase of earthquake strength and decrease of friction ratio;On the other hand,by SIMULINK technique sliding response of free-standing cultural relic under earthquakes can be effectively simulated which proves the technique useful.