Advanced Materials Research Vols. 446-449

Abstract: This paper mainly presents the research on serpiginous bars connectors of steel-concrete composite beams, which is used in practical engineering in recent years, and this paper also analyzes the characteristic and details of serpiginous bars connectors. According to the shear capacity of bend bar connectors and reversely bend bar connectors,the shear capacity calculation formulas are proposed on condition that frictional resistance on the contact surface have been ignored, which can provide references for engineering design.

Abstract: This paper presents an experimental study to know the seismic behaviour of the reinforced gangue concrete (RGC) columns. Four specimens of the RGC columns under cycle loadings were tested. The failure models, hysteretic performance, degradation rules of strength and stiffness, ductility and energy dissipation capacity are described and evaluated. It was concluded that the strength and stiffness of the RGC columns were improved with the increasing of steel ratio, column cross-section dimension and concrete strength. The tested RGC columns exhibit excellent seismic performance. The RGC columns have excellent ductility and can satisfy the request of the structural seismic design, thus they can be effectively used in RC structures.

Abstract: Nonlinear finite element model is established for the square interior constrained concrete filled steel tube column based on the research of the element type and material constitutive relation with finite element software ANSYS to find out the influence of the thickness of the steel tube, location of studs and geometry of the stirrups on the compression capacity of the short column, The results show that the compression capacity of the short column has something to do with the thickness of the steel tube and the studs, but the stirrups can eventually enhance a lot for the compression capacity as the validity is confirmed for the coherence of the results stepped from the finite element model and in test.

Abstract: This thesis studies deeply the crack development characteristics, failure pattern, hysteresis curve and the displacement ductility of unbonded precast reinforced concrete frame, by analyzing one unbonded precast reinforced concrete frame under low reversed cyclic load test. We build a model using finite element analysis software to the test piece model analysis, the analysis result agree well with the experimental results. So we build finite element analysis models with different design parameters to analysis the impaction for seismic performance. Numerical analysis results can provide a scientific reference for the unbonded precast frame structure design.

Abstract: Utilizing finite element program to calculate and analyze the settlement of eight models of frame tube structure with horizontal strengthened storey under the vertical loads, the conclusions are as below: Initially, setting strengthened storey effectively reduces the non-homogenious foundation settlement; Additionally, founfation settlement situations are different as the strengthened storey location changes. Generally, the closer strengthened storey to the substructure is, the better the effects on resisting non-homogenious settlement are.

Abstract: In order to investigate the effects of polyvinyl alcohol (PVA) fibers on the performance of concrete, such as strength, crack resistance, permeability and chloride penetration properties, experimental research were carried out in this paper . Three types of fiber reinforced concretes with 0, 0.5%, 1.0% volume fractions were designed with the same water to cement ratio of 0.43. Flat band method was used to evaluate the cracking resistance, while AutoCLAM and ASTM C1202 were adopted to measure the permeability of concrete. The experimental results showed that the workability and the compression strength decreased as PVA adding volume increasing. However, the tension and the bending strengths increased for PVA fiber concrete. The number of cracks induced by the shrinkage of concrete was reduced by adding more PVA fibers. The permeability and chloride penetration ascended as PVA volume increasing. However, all the parameters with regards to strength, crack resistance, permeability and chloride penetration for fiber reinforced concrete were more reasonable than those for the specimens without PVA fiber. In additional, a very good correlation between the permeability and the electric flux was found in this paper, that means both AutoCLAM and ASTM C1202 could be used for concrete penetration test.

Abstract: CTSRC (cold-formed thin-walled steel reinforced concrete) shear walls system studied herein is made up of cold-formed steel and concrete. Five shear walls were tested quasi-statically under low cyclic lateral loads. The characteristics including failure modes, hysteretic characteristics, ductility and stiffness degradation are investigated. Analytical result indicates that, the CTSRC shear wall structure possess adequate bearing capacity, good seismic performance and high ductility. Stirrup ratio of the restrained side columns had no significant influence on wall’s bearing capacity, but walls with higher stirrup ratio show higher ductility.

Abstract: Pedestrian underpass is an effective measure to relieve the pressure of city traffic congestion. The influence of the underpass construction to the surrounding environment is inevitable, sometimes it may affect the the normal use of ground buildings and underground pipeline. The background of the research is based on Hangzhou Qingtai pedestrian tunnel. The main content is to use the ABAQUS finite element software to simulate CRD-engineering tunnel excavation by two models considering the road rigidity or not, to find the discipline of ground displacement and Stress caused by shallow buried tunnel excavation under existing road. Comparison research was done with measurement results of actual project site, getting consistent results. This study can provide guide for the similar engineering practices.

Abstract: In a number of previous publications, results were reported for a series of extensive and carefully conducted tests on large scale reinforced concrete (R.C.) beams with various extents of loss of concrete cover and exposure of main reinforcement along their spans, with such areas of simulated damage being located within their regions which are dominated by either shear or flexure. These tests on R.C. beams made with normal strength concrete have covered a wide range of first order beam design parameters, with their results used to verify the generality of various theoretical models. In the present paper, much attention will be devoted to various structural characteristics (such as ultimate strength, flexural stiffness, etc.) of similar damaged R.C. beams with the proviso that, instead of the previously used normal strength concrete, the beams are made with high strength concrete. No such results (for high strength R.C. beams) have previously been reported in the public domain.

Abstract: Experiment research for aseismic performance of RC Column strengthened by self-compacting concrete under second force is completed. By comparing three comparison columns and three columns strengthened by self-compacting concrete in low-cycle reciprocating horizontal loads seismic performance test, the specimen described the typical features of breakage, and the hysteresis and ductility of the RC column reinforced or not by self-compacting concrete is analyzed, the reinforcement effect by the different initial force is compared. The results show that: reinforcement by increasing the cross-section of self-compacting concrete is an effective method to significantly improve the shear strength of reinforced concrete columns and specimen ductility. The presence of the initial force have impact on reinforcing effect of RC columns, the greater the initial force, the more obvious impact.