Papers by Keyword: Steel-Concrete Composite Beam

Abstract: This paper summarized and evaluated the girder construction methods of self-anchored suspension bridge, pointed out that the main beam linear would have a local depression between the largest span temporary pier when the steel-concrete composite beams were constructed by the incremental launching construction method, even if the main beam were withstand uniform bar-forces, moreover, the pre-camber curve of the main-girder could not arranged as a circle curve or quadratic parabola within the entire span. In view of this, the entire construction process of a self-anchored suspension bridge was analyzed by the finite element method, The results showed that the section property changes of the steel-concrete composite beam were the nature reason of the local depression on the main beam linear; The completed main beam was simplified into a three-span continuous beam which suffered vertical uniform distributing load and horizontal forces at the two ends, and the simplified formulas of calculating the vertical displacement of each span were derived by the force method; The numerical example showed that, the proposed simplified formulas could effectively solve the affection by the section property changes, accurately predicted the main beam cumulative vertical displacement, and the calculation accuracy could meet the engineering requirements, the conclusions of this paper had a strong guiding significance and reference value on the camber design and construction of the bridge wth the similar structural type.

Abstract: Steel-concrete composite beam prestressed with internal tendons (SCCPIT) is composed of prestressed concrete slab, steel beam and shear connectors, etc. At present, there is no calculation formula for crack width of SCCPIT in current design codes like European standard Eurocode 4 or American code ASSHTO LERD Bridge Design Specification (2004). In this paper, calculation formulas for crack width of nonprestressed steel-concrete composite beam provided in Code for Design of SteelConcrete Composite Structure (DL/T 50851999) were adopted as a basis for modification. On the basis of available test results, calculation formulas for uneven coefficient of reinforcement strain and average crack space were modified by consideration of concrete slab width and combined force ratio. Hence, empirical calculation formulas for crack width of SCCPIT under negative moment were proposed. In order to verify accuracy of proposed formulas, available test results including results of five simply supported SCCPITs previously conducted by author were introduced, and comparisons indicated that calculated values were in good agreement with test results.

Abstract: Steel-concrete composite beams have been widely used in the high-rise buildings and large span steel structure. Composite beams effective flange width has been further investigated in domestic, as well as the force and deformation within elastic stage and plastic stage. In this paper, we give out the formula derivation of steel-concrete composite beams stiffness amplified coefficient. Combined with a practical engineering, we analysis the impact of stiffness amplified coefficient on the whole structure by SAP2000 software and compare the results back and forth. In the end, we put forward some suggestions for construction engineers.

Abstract: It’s of great practical significance to improve the durability of steel-concrete composite beam structures.The deterioration of steel-concrete composite beams includes stud rust, reinforcement corrosion, corrosion of the steel beams and concrete performance degradation, which are caused by a number of factors. The corrosion mechanism of composite beams is discussed, and some basic issues remain to be solved in this area are analyzed in the paper. Besides, some research directions in the future are put forward.

Abstract: This paper presents a model test research on long-term deflection of prestressed steel-concrete composite beams caused by creep and shrinkage effects of concrete. The model is designed based on a 20.8m length segment of a service composite beam bridge in Guangzhou. Geometric scale between the model and prototype is 1:8. Long-term deflection of the test model was obtained through 300 days of uninterrupted test. In addition, using the CEB-FIP (1990) criterion, effective modulus of concrete was calculated considering the effect of the concrete creep and shrinkage. Uniform the effective modulus of concrete to the modulus of steel, the value of structures time varying stiffness was calculated with single material theory and the relationship between stiffness and deflection by introducing stiffness adjustment coefficients was established, then the value of deflection changing with time was calculated.

Abstract: Static load tests were conducted on two reversed-loading simply supported and two continuous outer-plated steel-concrete composite beams to study the formation and development of cracks in such beams under negative bending moment. The test results show that based on the plane section assumption, it is an effective and economical method to calculate the cracking moment of the composite beams assuming a rectangular stress block for concrete in tension zone. Considering the structural features of outer-plated steel-concrete composite beams, the formula for calculating crack width of concrete flange of outer-plated steel-concrete composite beams is discussed and presented, and the calculated values of crack width agree well with the experimental results.

Abstract: This paper has the background of JiuJiang bridge recover engineering, and uses the approach that combining submodel method with finite element method to establish the simplified model of the whole steel-concrete composite beam bridge without considering slipping and the refinde model of the typical section with considering slipping. The distribution of slipping of steel-concrete composite beam under the condition of operation is researched. In addition, the deflection as well the stress of typical section between the two kinds of models is contrasted and analyzed. Based on these researches, this article uses the Midas Civil to study the creep effect of steel-concrete composite beam cable-stayed bridge.

Abstract: Based on the test data of twelve push-out specimens with different holes filling different materials,the paper compared and analyzed the capacity and the corresponding slip value of the stud shear connector. The results show that, as to the two different kinds of holes shape ,the strength of the stud shear connectors of square push-out specimens was huger than that of circular specimens with the same condition; the strength of stud shear connectors in steel-concrete composite structure was decided by the strength of concrete surrounding the shear in the holes, with increasing concrete strength, the strength of stud shear connectors improved greatly; The outputs of this study are very useful for further understanding of the characteristics of the stud,it is also expected that the results presented in this paper should be valuable for the design of the composite beams.

Abstract: Steel-concrete composite girder is consisted of concrete slab and steel girder connected through shear connectors. Owing to shrinkage and creep of concrete, redistribution of structural internal force and stress should be caused. It is widely accepted that shrinkage and creep models of concrete possess large randomness. The influences of stochastic variation of creep and shrinkage model, compressive strength of concrete, elastic modulus model of concrete, ambient humidity, load and shear connector stiffness on structural responses of continuous steel-concrete composite beam are investigated in the present study. Through Latin Hypercube Sampling (LHS) approach, the time variant probabilistic responses of deflection, interface slip, and stress of concrete slab and steel girder of continuous steel-concrete composite beam are studied.

Abstract: In order to model the elasto-plastic behavior of steel-concrete beams in high-rise buildings correctly and conveniently, plastic hinge method is used. Based on experimental and theoretical research on composite beams, the trilinear moment-curvature skeleton curve of steel-concrete composite beams is amended by numerical simulation and theoretical analysis. And the 4 poly-line moment-curvature skeleton curve model is suggested for elasto-plastic analysis of steel-concrete composite beams. The elastic-plastic model is then used for real composite beams under monotonic load experimental analysis to verify its precision. The suggested model can lay a foundation for the dynamic analysis under strong earthquake for the globe steel-concrete composite structures.