Advanced Materials Research Vols. 163-167

Abstract: In order to improve the structure performance and reduce Life cycle cost of the structures, advanced fiber composite polymer is more and more frequently combined with conventional materials to develop new structures. FRP-concrete composite beams with prefabricated FRP shells, which are designed with steel bar as the main reinforcement and with suitable FRP participation proportion to improve the performance, are developed by us for their good integrated performance. The VIMP production process to produce the thin and large-scale FRP shell was developed and detailed in this paper and performance of the production was also examined. Results show that the FRP shell produced by VIMP are with rather good performance, and can be used in the composite beams. The VIMP is very suitable for this kind of thin and large-scale structures.

Abstract: In order to protect Chinese ancient buildings,a Qing Dynasty building in Sichuan province was taken as example to study its aseismic characters after strengthened. By ANSYS program,semi-rigid character of tenon-mortise joint as well as contact between wooden constitution and walls were simulated.Then by modal analysis basic frequency as well as main modes of the structure were obtained;By response spectrum analysis inner forces as well as displacements of the structure under 7-degree intensity of seldomly occurred earthquakes were obtained.Results show that after strengthened,main modes of the structure are of translation;Under 7-degree intensity of seldomly occurred earthquakes peak values of displacement as well as inner forces of the strengthened building are all within permissible scopes,which proves its good aseismic characters.

Abstract: Prestressing of lattice shell is realized by cable, and author put forward a new kind of layout: The prestressing has been brought to bear by hoop and radial element of single-layer lattice shell, which avoid cable's effect on architectural purpose. The element has been made to sleeve, and the magnitude of prestressing is dominated by bolt. Article shows an example of K6, K8 single-layer spherical lattice shell, and the prestressing have been exert on partial ribs and hoops. The prestressing has been calculated by element axial force under normal loading. Stability of shells have been studied, and show the deformation satisfy the criteria under normal loading; The ultimate capacity has been improved obviously, loads transfer is rational. The new layout of prestressing is a promising technique.

Abstract: The dynamic behavior of gangue concrete filled circular steel tube beam with different steel ratio under the cyclic loads are analyzed and studied based on finite element analysis software ABAQUS. Through reasonable modeling established, parameter set, an effective grid meshed, the hysteresis curve of gangue concrete filled circular steel tube beam under low-cycle reversed loading is given, and verified compared with the experimental results. The comparison shows that the simulated hysteretic curve gives results in close agreement with the experimental results. The simulated curve shows that there has the characteristic of spindle-shaped and no significant decline in stiffness of the hysteresis curve. And the fatness of hysteresis loop is better.

Abstract: Liquefied Natural Gas (LNG) tank is the important equipment in storage LNG. There has been a lot of research results abroad, but lack of seismic studies for the LNG tank in China. Domestic structural designers also have an urgent need for internal force and deformation law of LNG tanks under a variety of dynamic loads. This study focused on vibration characteristics and seismic response of a shell of LNG tank. Using ANSYS creat finite element model, obtain natural frequency and vibration mode etc. According to requirements of Chinese "code of building seismic design", analyze this shell of LNG tank of unidirectional horizontal seismic response under the action of selected three kinds of seismic waves. Time-history curves of LNG tank’s displacement, acceleration, stress distribution law under the action of selected three kinds of seismic waves are obtained.

Abstract: Based on the experimental results, this paper presents the effects of concrete-filled in chord on the static behavior of rectangular hollow section (RHS) steel tubular trusses, including failure modes, load bearing capacity and structural stiffness. Failure of RHS trusses occurs at joints wether concrete-filled in chord or not, concrete-filled in chord changed the failure mode. Load bearing capacity and stiffness of joints subjected to compression load increased significantly, while it is limited to the tension joints. Concrete-filled in the compression chord tube can increase its stiffness significantly, while tension chord tube, it is not that obvious. Finally, based on the results discussed, failure modes and their formulas of calculating the load bearing capacity are discussed. Meanwhile, two methods, that is, amplified factor method and stiffness discounting method, which calculate the structural displacement when considering the joint deformation effects are presented.

Abstract: In the article based on the geometric characteristics of the tower and force characteristics, the author designs the concrete-filled steel tube (CFST) 3 limbs column tower, and establishes finite element model of the tower. We carry on time history analysis of the concrete-filled steel tubular wind turbine tower based on finite element method when the earthquake wave is different. Under rare earthquake, the majority bars of the concrete-filled steel tube 3 limbs column tower are in the elastic stage, only a small number of bars in the top and the bottom are into the plastic phase. The post-seismic displacement at the top of tower is 1.1m which is slightly less than the tower height of 1 / 50 (1.26m) and meets the seismic requirements of the region. The analytical result may provide the foundational test data and advice for the design of the CFST wind turbine tower.

Abstract: A new type steel and glass fiber reinforced polymer (GFRP) deck composite beam has been proposed. The relative slip and shear force on the interface of steel and GFRP deck composite beam appears to a certainty with the external loading, which induced internal force redistribution between GFRP deck and steel beam and shear connector, especially GFRP is a resin material, its physical and mechanical properties will change with temperature and time. According to the structure and bearing characteristics, the interface shear force differential equations that considering the temperature and creep effects were presented, the theoretical calculating formula of shear force were given under the uniform load. Results of calculation showed that the shear force of composite cross-section would increases with the increase of the connection stiffness, the increase of load, the change of temperature and the time. Loading effect and temperature changes creates a relatively larger impact on the shear force of the composite beam, while the stiffness of the connective interface and the creep effect of the GFRP material to composite beam shear force were much little.

Abstract: A steel-concrete composite slim beam, with its steel section encased in a concrete slab, provides a composite steel-concrete floor construction with minimum depth and high fire resistance. It has become popular in multi-storey steel buildings throughout Europe in recent years and also been used in some projects in China. For the structural engineer, it is critical to understand the behavior of composite slim beam in the sagging moment region. In this paper, the bending capacity and flexural stiffness of the composite slim beams in sagging moment region are investigated theoretically. Meanwhile, the stiffness and bending capacity are given by Finite Element Analysis (FEA). The experiment of a simply supported beam has been carried out in order to validate the theoretical results.

Abstract: In order to research the seismic behavior of lightweight aggregate concrete-filled rectangular steel tubular (CFRST) frame, four test specimens were experimentally studied under constant axial load and cyclically lateral load. The form of beam section and steel ratio of column section were considered as experimental parameters. The results show that the lightweight aggregate CFRST frame has plump hysteretic loops without obvious shrinkage phenomenon; the displacement ductility coefficients is between 3.00 and 3.74, which can meet the requirement of ductile frames; the bearing capacity, ductility and energy dissipation capability improve with the increase of the steel ratio; when the steel ratio is the same, the steel beam frames have plumper hysteretic loops, the ductility and energy dissipation capability increase to some extent, the stiffness degradation is slower compared with the CFRST beam frames. Conclusively, the lightweight aggregate CFRST frame has excellent seismic behavior and mechanical performance and there is the value to further research.