Advanced Materials Research Vols. 163-167

Abstract: With the development of computer science, the finite element method has been used widely. The paper used the ABAQUS finite element analysis software to carry out the finite element analysis on the middle long columns of high-strength concrete filled square steel tube with inner CFRP circular tube under compressive load. The results of finite element analysis were obtained, which agreed well with theoretical data. This conclusion proved the correctness and feasibility of finite element model.

Abstract: In this paper, the effect of viscous damper on seismic performance of steel-concrete hybrid structure for high-rise building is analyzed. The result shows that viscous damper has little effect on dynamic properties of structure. The story lateral displacement, story drift rotation and damage of structure can be reduced effectively by viscous damper. The effect of the viscous damper on structure seismic performance is better with the increase of seismic intensity. Under the 7, 8 and 9 degree seismic seldom intensity, the story lateral displacement of the top floor decreases at 17.2%, 23.3%, 33.4% and the story drift rotation decreases at 20.8%, 27.2%, 44.7% respectively. The seismic analysis result may be referred by designer and researcher.

Abstract: This paper is to make an elastic dynamic time history analysis on a steel-concrete composite structure under the effect of frequent earthquake. And it reveals the collaborative performance of steel frame and RC frame under the seismic motion effect by studying time history response of the parameters like base shear, base bending moment, structure top acceleration and displacement of the structures under the seismic motion effect. The results show that for the steel-concrete composite frame structure under the seismic motion effect, its maximum base shear, maximum bending moment, structure maximum top acceleration and maximum displacement do not occur at the same time, and dynamic response of the top steel frame acceleration, displacement and other parameters increase more significantly than the lower RC frame, while Steel-concrete composite structure may produce resonant phenomenon with earthquake vibration.

Abstract: Xijiang River Bridge is the first hybrid railway bridge composed of single pylon cable-stayed and continuous rigid-frame system in China. To study the mechanical behaviors of the novel bridge, 3-D finite element model (FEM) based on Midas/Civil software is created; spatial effect of stayed cable is discussed; the self-vibration behavior of this unique bridge is analyzed by adopting the subspace iteration method; then by means of simulating analysis of the whole construction process, stress paths of critical parts in different construction stages are calculated and presented to study its mechanical behaviors. Results reveal that the composite bridge embodies features of both traditional cable-stayed bridge and rigid-frame bridge. Further study, however, shows that the unique hybrid system is mostly characterized by the rigid-frame type, meanwhile, as safety storage, the stay cable will play an important role in the “stiffness kept” of the whole structure, improving the actual stress and working condition of the whole structure in the long run.

Abstract: The paper presents a numerical method for calculating the load-deformation response and ultimate load carrying capacity of Concrete Filled Steel Tubular (CFST) latticed columns A half-wave sinusoidal function is assumed for the deflected shape of the column. The effect of confinement and shear deformation are included in the analysis, and the corresponding equilibrium equation is established. The method applies to eccentrically loaded compression members bent in single curvature. Unequal end eccentricities can be considered. Test results are reported for seventeen four latticed column specimens with varying end eccentricities and slenderness ratios. The obtained results show that eccentricity has significant effect on the bearing capacity of specimen, and the slenderness ratio also has some influence. The diagonal lacing bars remained in the elastic state during the entire load range. When specimens go into the nonlinear stage, Poisson's ratio of the near-load steel tube increases and a significant confinement effect can be observed. For the far-load steel tube, confinement effect does not occur to a significant extent. Specimen failure is due to overall instability except in the case of several individual short columns. Good agreement was found between the theoretical and experimental results using the numerical method developed in the paper. The proposed numerical method is shown to be more accurate than the current method presented in the Chinese code.

Abstract: Combined with the merits of light wood frame structure and Chinese ancient wood structure, a light wall composed of oriented structural straw board (OSSB) and tennon-and-mortise connection wood frame (TMCWF) was developed. The wall build-up with several wall-modular those are composed of wood frames and panels based on its width, the wood frame members are connected with tennon-and-mortise, and the panel is OSSB which is cheap and low-carbon, so the wall have many merits such as lower cost, better earthquake-resistance and good to environment protection. To research the shear behavior of the light wall composed of OSSB and TMCWF, nine wall-modular were tested under level unidirectional loading. The performances of the specimens such as the damage characteristic, shear capacity and rigidity are obtained. Factors that influence the shear capacity and elastic rigidity, including space of vertical frame members, nail space, panel thickness, type of panel and vertical load, were analyzed. And the shear behaviors of the light wall composed of OSSB and TMCWF and the light wood frame wall were compared. Experimental results show that the shear strength and rigidity of the developed wall with TMCWF are higher than those of the light wood frame wall. And the panel type, the panel thickness, nail space of the panel are the major factors to influence the shear strength of the wall-modular.

Abstract: This paper provided three test data pertaining to the mechanical properties of steel reinforced concrete (SRC) eccentric columns after exposure to fire and one comparative test data pertaining to the mechanical properties of steel reinforced concrete columns at room temperature. The influence of eccentricity on failure mode, distortion performance and ultimate load bearing capacity are mainly studied. Test results show that the failure modes of steel reinforced concrete eccentric columns after exposure to fire are similar to that at room temperature. Strain along the section height at mid-span section of eccentric columns before loaded to 90% ultimate load bearing capacity is linearly distributed and well agree with the plane section supposition. After exposure to fire, the flexural rigidity and load bearing capacity of specimens are all declined compared with that at normal temperature. In various loading stages from the initial loading to 80% ultimate strength, the ratio of flexural rigidity of SRC eccentric columns after exposure to fire and at normal temperature is ranged from 0.30 to 0.59. With the same concrete strength and heating condition, the ultimate strength of specimens decreases with the increasing of eccentricity. The ultimate bearing capacity of all specimens at normal room temperature is calculated on the method proposed by Chinese regulation JGJ 138-2001. The compared results of experimental values and calculating values show that the residual load bearing capacity of SRC eccentric columns after exposure to fire is about 69% to 81% of that at room temperature.

Abstract: In recent years, the progressive collapse of buildings increases the interest in progressive collapse studies. If a key column fails in structure, the internal force is redistributed by the catenary action of joint to prevent its progressive collapse. The joint connecting to the failed column is under the state of bending moment combined with tensional force and the tensional force would affect the moment-resistance ability and ductility of joint. In this paper, the finite element software ABAQUS is applied to analyze the behavior of composite joints under the state of bending moment combined with tensional force. The effects of rebar ratio, rebar strength, concrete strength, etc., on the behavior of joints are investigated. The results show that high strength steel is suggested to be used in composite joint to improve its bending moment capacity and tensional capacity.

Abstract: Model test investigation on rectangular section composite micro-pile structure used for earth slope reinforcement has been performed, including the mechanical and deformation properties and pile spacing influence on anti-sliding capacity. Test results have shown the main following conclusions. For the rectangular section composite micro-pile structure and the similar soil in tests, micro-pile row spacing along the lateral load direction ranging from 4D to 6D (D is the diameter of micro-pile) can provide higher anti-sliding capacity. Active earth pressure of the first row pile is larger than that of other piles when the anti-sliding potential of composite micro-pile structure is fully developed. Relative deformation of the first row pile is larger than that of the middle and last row piles above the slip surface, while relative deformation of the last row pile is larger than that of other piles beneath the slip surface. The main failure mode of the rectangular section composite micro-pile structure can be regarded as bending failure in certain range near the slip surface.

Abstract: Rotational construction for bridges attracts much attention of people because it is featured by its low initial cost, fast and easy operation and minimum traffic interruption. Nowadays, rotational bridges have been mostly built by the level rotation method of the ring combining with ball joints at home and abroad, which is more safe and easy to control the closed precision, but the large rotating friction restrict the promotion of the rotational weight and span. The author takes flat hinge supported by single point as the rotating bearing type, using embedded four fluorine board, controlling wheel construction precision strictly. In that case, Suifen He cabl-stayed bridge, weigh up to to 14000t, has been successfully complished rotational construction with the help of continuous jack. The built bridge axis deviation is limited within 3mm, and maximum deck height deviation is only 12mm. It is proved that rotational construction of flat hinge joints supported by single point can efficiently solve the colsed accuracy which is difficult to control and problems of heavy rotating traction, as long as the installation precision and the sliding performance can be controlled.