Papers by Keyword: Composite Beam

Abstract: In this paper, considering the method of theoretical analysis, the state of strain and stress on each section of composite beam of concrete−filled square steel tubes and T−beam is studied in the process of bending. According to structural and mechanical characteristics of composite beam, elastic analysis method is employed for stress analysis, and the calculation equations of elastic bend-bearing capacity of simply supported composite beam is given. Then the calculation equations of plastic limit bend-bearing capacity is deduced according to the unified theory.

Abstract: Compared with traditional steel-concrete composite beam,authors describe a new composite beamencased-steel-reinforced concrete composite beam , introduce the advantages of this new composite beam,and establish the formula of ultimate bearing capacity.

Abstract: Introducing low cost housing is one of the challenges face civil engineers now-days. Using lightweight construction materials i.e. cold formed steel sections is an alternate solution to overcome the challenge. In this study, a lightweight composite beam was introduced. It consists of cold formed steel section and profiled concrete slab. Experimental push tests were conducted to investigate the ductility and strength capacities of new and innovative shear connectors. The shear connectors were easy to form and give advantages to speed up the fabrication process of the proposed composite beam. The shear connectors showed large deformation and strength capacities. It is concluded that the proposed shear connectors could be used for lightweight composite beams.

Abstract: The experiment on joints of concrete filled thin-walled steel tube and the composite beam is carried out in 8 specimens, and mechanics performance of all type joints is concluded in general. The test results indicate that each joint has higher bearing capacity and better ductility performance. Solid65 and Shell181 Elements of ANSYS finite element program are adopted to simulate concrete and thin-walled steel sheet of composite beams and columns. Calculation results in theories proved conformity with the test in primary.

Abstract: When the concrete and steel combined composite beam is exposed to high temperature, concrete could delay temperature rising of steel by covering or increase heat capacity of structural member. For becoming of structural reinforcing by unification between materials, fire resistance rate of composite beam would be higher than simple steel beam. The temperature rising of exposed steel of composite beam is directly related with section shape and exposure length of steel. In this study, fire resistant tests were carried out for composite beams and steel beam with same thickness of spray-type fire resistant materials in standard fire, and after that, temperature histories were analyzed and compared with shape factor. The correlation between steel temperature and shape factor was showed very high. This result suggests that if it can be predict the comparative advantage of member by factor which cause the performance enhancement, it could be conclude that an Standard Accreditation method can be adjust to members without individual certificate of accreditation.

Abstract: As a new material type, elastic concrete has been used in pavement and bridge deck paving due to its superior properties to ordinary concrete. Nowadays, fatigue behavior of steel-concrete composite beams has become the focus in engineering design. This paper summarized the research status, methods, influence factors on fatigue behavior of elastic concrete and steel-concrete composite beams and compared various fatigue specifications among different countries. The result shows that elastic concrete has longer fatigue life than ordinary concrete, so we can solve fatigue problems by using elastic concrete instead of ordinary concrete in composite beams. Finally the author puts forward suggestions for further advanced study in this area.

Abstract: In the newly developed excavation system for construction of basement of building, steel elements plays a role as temporary member before casting floor concrete, but it do behavior as composite beam mixed with concrete after floor slab has been casted. That is, it is necessary to review if axial stress loaded in steel beam can be conveyed properly to slab, as casting concrete slab under conditions of application of compression to the steel beam In this manner, this paper presents the experimental result of the composite beam subjected to both constant axial load and variable vertical load. Main parameters in the test are magnitude and loading time of axial force. As a result, it was found that there was no effect on the flexural strength according to the timing of compression and axial force. The flexural strength of the composite beam subjected to both a constant axial compression and increasing vertical load could be predicted with somewhat safety by using code equations.

Abstract: To investigate the flexural bearing capacity in negative moment region of composite beams，we examined different ends constraint components. The modeling of the beam ends connected framework has been done by the finite element software ANSYS. The concrete thickness, slab reinforcement ratio and different component at the edge of the composite framework in the negative moment region are taken into account. The performance during the process of deformation and failure are got by nonlinear analysis. The flexural bearing capacity was reported, with the negative moment region of the composite frame beam, it revealed great differences when the beams are different component. Simulation results show that the concrete thickness take the biggest influence on bearing capacity. The results showed the behaviors of the composite frame beams are different with positive moment region, and calculation based on current code for design of steel structure (GB50017-2003) would be a big deviation.

Abstract: Steel and concrete composite beam is a kind of composite beam which the steel and the concrete are connected by shear connectors. Now, many experts and scholars have carried out many experimental research and theoretical analysis about it. But, steel and concrete composite beams strengthened with prestressed FRP bars have not been studied. Based on the structure, the nonlinear analysis mode of steel and concrete composite beams strengthened with prestressed FRP bars is proposed, the calculating program is researched. The relationships between moment and curvature, also between load and deformation of steel and concrete composite beams strengthened with prestressed FRP bars are obtained. The results show that the moment-curvature curve and load-deformation curve of steel and concrete composite beams strengthened with prestressed FRP bars can be separated to elastic stage, elastic-plastic stage and plastic stage.

Abstract: This paper presents a spectral element model for the laminated composite beams with a surface-bonded PZT layer. The spectral element model represented by exact dynamic stiffness matrix is derived in the frequency-domain by using the frequency-dependent dynamic shape functions which are formulated from the free wave solutions satisfying the governing differential equations transformed into the frequency-domain by using the DFT theory. The performance of the present spectral element model is then evaluated by comparing its solutions with those obtained by using the conventional finite element model