Advanced Materials Research Vols. 243-249

Abstract: Considering unavoidability of torsional vibration of high-rise buildings during earthquake, for a simpler and more accurate way to compute the maximum interstory drifts, through establishment of different structure calculation model. Structure analysis program CANNY 3D was used to conduct 3D and 2D time-history analyses on irregular steel structure models under frequently occurred small earthquakes and large earthquakes. Finally, by comparing maximum interstory drifts between each floor, a method was presented to simplify 3D computation of elastic-plastic interstory displacement of high-rise irregular steel structure into a computation plane 2D structure.

Abstract: In order to analyze seismic behavior of large-scale exterior joints of high-rise precast concrete structures, an experimental study on seismic performances of precast beam to column exterior joints with composite slab was conducted with large full-scale models. The failure pattern, hysteretic characteristic, skeleton curve, displacement ductility and energy dissipation, were analyzed. The results provided some information about the seismic behavior of the joint. However, due to the unique nature of the specimens, several other key parameters could not be varied. Therefore, a numerical joint model taking the bar slippage into consideration was developed based on the OPENSEES software and validated against the results of experimental test, then the parameters analysis was carried out. The study results indicated that the overall seismic performance of cast-in-place joint is almost equal to that of the monolithic specimen.

Abstract: By means of the tests on the mechanics performance of the reinforcing concrete mixed with sisal fibers or rubber powder of certain content are investigated. The compressive strength, tensile strength and flexural strength, etc. are compared. The test indicates that when the test condition is same, the compressive strength, tensile strength and flexural strength of the sisal fibers concrete are better than those of the rubber powder’s. The sisal fiber concrete is environment friendly than the rubber powder concrete. And it has widely value of spread and utilization.

Abstract: A model of full scale one-bay, one storey was tested under low cyclic loading in order to study the hysteretic behavior of steel frames with sandwich composite (SC) panels. According to the failure pattern and damage process of test specimen, seismic behaviors were evaluated. Hysterics loops, skeleton curves, curves of strength degradation, and curves of stiffness degradation, ductility index and viscous damping coefficient were analyzed. Test results show that the failures of panels mainly occurred around the embedded parts, but compared with traditional panels and walls, SC panels exhibit a better integration. The connection between panel and steel frame is vital to the mutual work of the two parts. Finally, seismic design recommendations based on the analysis of ductility index and energy dissipation of the structures are presented.

Abstract: This study presents a kind of new model correlates air and pavement temperatures in bituminous pavement. Based on abundant measured temperature data in Henan Province, China, distribution laws in asphalt conctete pavement temperature is studied detailed and the dependency between air and pavement temperature is discussed by the method of regression analysis and the prediction models of asphalt pavement temperature are established. Comparisons between measured and predicted asphalt pavement temperatures indicate that the models are equipped with comprehensive applicability and excellent accuracy.

Abstract: Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) has been a technological breakthrough offering compressive strength over 100MPa and tensile strength over 10MPa with true ductile behavior. Three types of frequently used fibers including flattened end, hooked end and crimped fibers, were used in producing UHPFRC with fiber volume ratios of 1%, 2%, 2.5% and 3% to investigate different reinforcing effect of fiber geometry on UHPFRC. The results showed that specimens with flatted fibers showed the highest flexural tensile strength, and specimens with crimped fibers showed the lowest flexural tensile strength. The optimum volume ratio for the flattened end fibers or hooked end fiber was 2%. The hooked end fibers were more preferable for producing ductile UHPFRC.

Abstract: Based on strut-and-tie model (STM) in deep beams, steel truss reinforced concrete (STRC) deep beam was developed. Experimental investigations of mechanical performances of STRC deep beams were carried out, and results show that STRC deep beam is of high ultimate bearing capacity, large rigidity and good ductility; Strut-and-tie force transference model is formed in STRC deep beams, and loads can be transferred in the shortest and direct way. Then Steel reinforced concrete (SRC) strut-and-tie model (SSTM) for determining the shear strength of STRC deep beams is proposed. The contribution of SRC diagonal strut, longitudinal reinforcements, stirrups and web reinforcements to the shear strength of STRC deep beams are determined with consideration of softened effects of concrete, and for safe consideration, superposition theory is employed for SRC struts. Computer programs are developed to calculate the shear strength of STRC deep beams and verified by experimental results.

Abstract: A large eddy simulation algorithm for numerically calculating unsteady wind field around complex geometry building was given. In this algorithm, a curvilinear coordinate system was used to formulate the numerical model, so the complex wind-structure interface could be described precisely. Governing equations were discretized by central differencing schemes with co-located grids. The convection velocity was interpolated by using Rhie-Chow method in order to avoid the inherent odd-even decoupling problem. A common Maker and Cell (MAC) scheme was used to split the velocity-pressure linkage in Navier-Stockes (NS) equation. An explicit Adams-Bashforth differencing scheme was applied for time marching. A corresponding computer code was developed and was validated by performing on simulation of wind field around full-scale Texas Tech University (TTU) building model. Furthermore, the simulation results were compared with corresponding field measure data and wind-tunnel experiment results reported by other authors. The comparison showed that this algorithm is feasible for numerical simulation of unsteady wind field around buildings.

Abstract: The steel tube confined concrete (STCC) column exhibits excellent mechanical performance. A 3-D finite element model (FEM) using ABAQUS was established to simulate the performance of the composite joints with STCC column and RC beam. Accurate material model, rational element type, and solution method were discussed. Some STCC columns and composite joints with concrete-filled steel tubular (CFST) column and STCC column were modeled based on the model, respectively. The results from FEM are good agreement with the test results. The mechanism of the composite joint was investigated based on the FEM.

Abstract: Progressive collapse is a chain reaction of failure that relates local damage to large disproportional scale collapse in a structure. At present the research against progressive collapse focused on reinforced concrete (RC) and steel structures. This paper presented the state-of-the-art of study on progressive collapse of structures. A preliminary analysis on the progressive collapse of a typical planar composite frame with concrete-filled steel tubular (CFST) columns was performed using ABAQUS. Some general conclusions were given to refer for the further research on the composite frames.