Experimental Analysis for Steel Box Concrete Composite Beam of Arch Bridge

A new steel concrete composite structure was proposed which composed of steel box beam, PC beam and PBH Shear connection. Bend test was carried out for the performance study of deformation and stress. It was found that Material advantages of steel and concrete were fully used and crack of concrete and local instability of steel box were avoided. And the deformation between steel box and concrete can be smoothed with PBH shear connection. As the calculated values showed good agreements with the test results, the proposed formulas can be reliably applied to the practice analysis. With the different parameters analysis, mechanic performance of the composite was obtained.     

Hysteretic Behavior of Composite Deep Beam Infilled Steel Frame

The Quasi static tests of one steel frame and two the composite deep beams infilled steel frames were carried out. The effects of the deep beams on the load capacity, ductility, hysteretic property and energy dissipation of pure steel structure were analyzed. It is found that the hysteresis curve is a straight line with the constant of the stiffness at the beginning and without residual deformation. And the hysteresis curve of specimen was full after yielding, and the skeleton curves had a clear plastic flow phase with triple linear. The lateral drifts of the beam specimens at failure were 1/25 and 1/22. The composite deep beams enhance the initial stiffness, yield load and maximum load bearing capacity of steel frame. Therefore, seismic performance of the composite deep beams is better.     

Finite Element Analysis of the Influence of Steel Strength on Beam-to-column Composite Connections

Because high material strength and composite load-bearing are emphasized in constructing members for high-rise steel frame structures, in a composite connection, steel strength has a dramatic influence on both the bearing performance and the composite action of the concrete slab. Based on a finite element analysis, we discuss the composite effect and the connection breaking mode, focusing on the performance change of the composite effect in adopting high strength steel. It can be found from the results that, along with the improvement of the steel strength, the elastic and plastic ultimate strength of the composite connection will increase, the ductility will decrease to a certain extent, and the composite effect of the concrete slab will diminish. The collapse of the concrete in a positive moment side contacting the column flange is viewed as the limiting state of the connection.     

Theoretical and Experimental Analysis of Bending Behavior of Composite Beam with Notched Web

A new kind of steel-concrete composite beam with notched web is proposed, and the bend and shear behaviors of this composite beam are investigated. First of all, the constitution, bearing characteristics and merits of the steel-concrete composite beam with notched web are introduced; then, a group of formulas about the bending capacity, slip between the steel beam and the concrete flange, and the deflection are introduced; after that, the bending behavior, slip effect and bearing characteristic of the steel-concrete composite beam with notched web are studied on 4 specimens, which are tested by applying two concreted vertical loads on the top of concrete flange. And the finite element model is adopted to analyze the results of the 4 specimens; finally, the reliabilities of the formulas are verified by comparing the results of theoretical formulas, the results of tests and that of finite element analysis. Study shows that the bend behavior and shear behavior are fine, and the popularization of this new kind of composite beam which can be broadly used in building engineering will save the consumption of steel.     

Mechanical Model of Steel Plate Composite Shear Walls

Based on concepts of mechanics, a mechanical model of novel type of steel plate composite shear wall is presented. The novel type of structure is formed by steel plate shear wall and T-shaped solid-web composite columns. Flexural stiffness of steel beams, lateral stiffness of the T-shaped solid-web composite columns, shear stiffness of steel plate composite shear wall and shear stiffness of beam-column connection are taken into account in the mechanical model. And the equivalent damping between steel plate and boundary is considered. Based on the deformation features of structures and the calculation hypothesis, the lateral stiffness model and the energy dissipation model of structures are developed. Meanwhile, the calculation equations of elastic ultimate and plastic ultimate of shear strength of structures are set up. The theoretical analysis results inosculate better with the results of experiment. The comparison between the result calculated from the formula and the experimental result shows that the calculation precision is high enough to meet the demand of theoretical analysis. The difference, including equivalent model, stress states, manufacturing defect and installation error, between the formula and the experiment has been further discussed.     

Experimental Analysis on the Longitudinal Shear Resistance of Flat-type Composite Slab

The shear bond behavior of the flat-type composite deck slab, Econdek65-675 is investigated primarily. Based on the Euro code 4, the relevant value, m-k, is achieved based on the test of 18 composite slab specimens. According to the thickness which is 115 mm, 150 mm and 200 mm respectively, these 18 specimens were divided into three groups with two sets in each group. One set was tested for shorter shear span loading and the other one was set for longer shear span loading. It is shown that the Euro code 4 is more accurate than the American code. Meanwhile, the calculation formula of longitudinal shear resistance of the composite slab as well as its relevant curve is presented. Compared with other similar composite slabs, it is proved that Econdek65-675 possesses reliable composite efficiency.     

Experimental Analysis on Beam-column Behavior of Steel-concrete Composite Pylon

Ten specimens with perforated ribs, which can be divided into two series, were made to observe the behavior of steel-concrete composite pylon under axial load and cyclic load respectively. The experiment reveals the ultimate capacity and failure mode of two types of specimens under the cyclic load with different actual axial load level. Furthermore, it can be concluded from the results that the failure mode can be divided into two types, that is compression failure and tension failure. And the behavior of those specimens under cyclic load is influenced significantly under high axial load or without axial load at all. In addition, perforated ribs will prevent the plates under compression from overall buckling effectively based on the observation that the wavelength of plate is limited between two neighboring perforated ribs. At last, comparison on the interaction behaviors of the axial load (N) versus moment (M) is made between the results of experiment and calculation according to the criteria.     

Optimization Algorithm Research on the Arch Axis of Steel Box-Concrete Composite Arch Bridge

The paper proposed an innovative optimized design philosophy of the optimal arch axis of steel box-concrete arch bridge. Formulas to calculate the arch axis at the arch crown and the arch springing of this type of arch bridge were respectively derived wit     

Experimental Analysis of Time-dependent Shear Behavior on Stud Connectors

With regard to the long span continuous composite beams, the early composite shear stud strength at the joint surface between the steel girder and concrete slab at different concrete ages should be considered while the concrete slabs are casted by phases in construction stage. In this study, the push-out test of stud shear connectors were conduced at different concrete ages. Meanwhile, the change law of the ultimate shear strength, ultimate slip deformation, design shear strength, and shear stiffness of the stud shear connectors with concrete ages were analyzed, and the corresponding time-dependent calculation equations were presented. The results include that the main failure modes of stud shear connectors are the concrete slab splitting failure before 3-days concrete age. The load-slip laws of stud shear connectors at different concrete ages are basically the same, however, the shear strength and stiffness all increase with the concrete ages prolonging, and the increase degree is faster at early ages, but slower at later ages, which indicates that the early composite shear stud strength at the joint surface of composite beams should not be neglected.     

Finite Element Analysis of Hysteretic Behavior of PR Steel Frame-steel Plate Shear Wall

In order to investigate the seismic behavior of partially-restrained steel plate shear wall (Steel Plate Shear Wall, SPSW), the effects of partially-restrained connection on the hysteretic behavior, lateral bearing capacity, stiffness, energy dissipation of SPSW with strong and weak steel frame were simulated under low cyclic loading via equivalent strip model that had been verified by experiment. The results show that hysteretic behavior of SPSW has dual characters. The hysteretic curves of SPSW with strong surrounding steel frame become fat, and the hysteretic curves of SPSW with weak surrounding steel frame become narrow. With the increase of the bending capacity of PR connection, the hysteretic curves of SPSW become fat gradually, and the capacity of energy dissipation and lateral bearing increase. However, the effect on lateral stiffness of PR connection of SPSW with strong steel frame is higher than the one with weak steel frame.     

Torsion behavior of Steel encased Concrete Composite Beams

In order to study torsion behavior of steel encased concrete composite beams, experiments were carried out with eight specimens. The destruction shape, working mechanism and the crack development and distribution were analyzed under pure torsion and combine torsion conditions. And also the relationships were investigated between torque and torsion ratio, load and strain, bending moment and deflection and load crack. On the basis of elasticity plastic theory, the formulas of cracking torsion were presented for pure torsion and combined torsion of combined beam. And with spatial truss model of variable angle, formulas for ultimate torsion strength of pure torsion and combined torsion were put forward. The predicted results were in good agreement with measured ones. The proposed formulas provided basis for evaluating safety and stability of the structural.     

Experimental Investigation on the Aseismic Behavior of Seismic Damage Masonry Wall Retrofitted with Grouting and Steel Hoops

In order to accurately evaluate the aseismic behavior of the seismic damaged masonry pagodas destroyed by Wenchuan earthquake and strengthened after the earthquake, a test was conducted to acquire related parameters on seismic performance from the specimens made by masonry and retrofitted with grouting and steel hoops. Taking a seismic damaged ancient masonry pagoda in Sichuan as a case study, four kinds of primitive specimens are fabricated by simulating the conformation of the masonry pagoda. Then the primitive specimens are destroyed under cycle loads and the damaged specimens are repaired by grouting and steel hoops. Cycle controlling tests are conducted with the specimens and relevant data are acquired. Experimental results showed that grouting combined with steel hoops could improve the ductility and energy dissipation capacity of a seismic damage of brick masonry structure, but it do a little to improve the stiffness of a seismic damage structure. And the cracking load of the repaired masonry is much lower than the original undamaged structure.     

Effect of Reinforcement Beam Sticking Different Layers Steel

This paper constituted the FEM(finite element method) model of sticky steel reinforcement beam and the model was used to analyze the reinforcement effect of the beam sticking different layers'' steel plate. The result shows two layers of steel is better than others, which agrees with theoretic analysis. It illuminate that the FEM model is in point for sticky steel reinforcement beam without crack.     

FEM Dynamical Analysis of the Reinforced Concrete Beam with Bonding Steel Plate

In order to researchmechanical capability of the reinforced concrete beam with bonding steel plate, adopting separatemethod to establish finite element model of the reinforced concrete beam with bonding steel plate, using FEM to study dynamical characteristics of the model, have got good results which can not be easily got using traditional resolution method, which can give referenceto study dynamical characteristics of the reinforced concrete beam with bonding steel plate.     

Analysis on the Behavior of Diaphragm Through Connection between Steel Beam and Concrete-filled Steel Tubular Column

Diaphragm through connection is a new kind of connection between steel beam and concrete-filled steel tubular column. Quasi-static test and numerical simulation had been carried out to investigate the behaviors of diaphragm through connection used in Zhonghai Square. The results show that, the bearing capacity, rigid and ductility of the diaphragm through connection are excellent, and the seismic principle, i.e., ‘strong column but weak beam’ and ‘strong connection but weak component’, is reached. The numerical model of diaphragm through connection was provided, and the results drawn from the model agreed with the test results. Influences of diaphragm dimension on the behaviors of the diaphragm through connection with praposed the numerical model had been investigated, and the design suggestion was provided based on the analysis.     

Finite Element Modeling of Stainless Steel Plates in Compression and Structural Behavior

The behavior of plate in compression plays a basic role in relevant research. There are significant differences between stainless steel and carbon steel plates in structural behavior. Analysis on the behavior of stainless steel plate in compression was presented. The development of FE models for analyzing stainless steel plates in compression was described based on the results of Rasmussen's test. And the strength curve was achieved by such advanced FE models with a high degree of accuracy. The explicit strength equations and design method were proposed for determining the local buckling strength of stainless plate and cold formed rectangular hollow section in compression. It is shown that the numerical simulation results achieved by using Quach model are accurate.     

Experimental Analysis on the Frost Resistance of Steel Fiber Reinforced Concrete

The frost resistance of steel fiber reinforced concrete (SFRC) was studied based on the fast freeze thaw tests in water and in a 3.5% sodium chloride solution, with different mass fraction of steel fiber in concrete at 0%, 0.5%, 1.0%, 1.5% and 2.0%, respectively. The effects of the number of freeze thaw cycles and the volume fraction of steel fiber on the mass lose rate, the splitting strength loss rate and the dynamic modulus of elasticity of SFRC were analyzed. The reinforcement mechanism of the steel fiber under the action of freeze and thaw was also discussed. Moreover, mercury intrusion method and SEM analysis were carried out to study the pore size distribution features and the performance of microstructure on the impact of frost resistance of SFRC. The results show that adding an appropriate amount of steel fiber into concrete can reduce the pore porosity and improve the compactness of concrete. Furthermore, the presence of steel fiber proves to shrink the porosity and improve evidently the frost resistance of concrete. It is also shown that the steel fiber content has a great influence on the frost resisting property of SFRC. The best performance of SFRC can be achieved when the volume fraction of steel fiber is 1.5%.     

Experimental Analysis on Behavior of Cold formed Steel Box Built up Section Columns under Axial Compression

17 specimens of cold formed steel box built up setion columns were tested under axial compression load. The section forms were divided into two categories: A and B. Load displacement curves and failure characteristics of specimens were obtained. The test results are compared with the caculated results according to “effective ratio of width to thickness” in code of “Technical code of cold formed thin wall steel structures” (GB 50018－2002), “effective section method” and “direct strength method” in AISI specification. The results show that: the failure characteristics of LC and MC series columns are overall flexural buckling, while SC series columns are local buckling and ends confined damage. The ultimate bearing capacity of B categories section columns is three times as great as that of A categories section columns, so it has the effect of “1+1＞2”. The results calculated according to “GB50018” and AISI specification are much conservative for LC series columns of A categories section, while in agreement with test results for MC and SC series columns. For B categories section columns, the calculated results are non conservative for LC and MC series columns, while conservative for SC series columns.     

Analysis on Mechanical Behavior of Welding-Overlap Splices for Mid-Diameter Steel Bars

An improved splice method for mid-diameter steel bars (10-16mm) used in RC structures was developed, which can make the installation more easily and economic through the hybrid connection of welding and overlapping. In order to study the mechanical behavior of welding-overlap splices, a total of 138 steel bar splice tests were conducted, including both the steel-concrete interaction group and the lonely-steel group. Through the splice tensile experiment, the failure model and ultimate strength of the improved splice was summarized. Meanwhile, the failure mechanism was analyzed by the FEM analysis. The test results show that: hybrid connection of welding and overlapping is a simpler splice method which can realized the reliable splice in the RC structures, the ultimate load of the improved splice is sufficient for the application and the failure model is reasonable. Base on the test results, some suggestions for application were given. The economic analysis of a real application case is conducted, which shows a good prospect of proposed connection.     

Determination Method on Diameter of Cables in Mega Steel Frame and Composite Brace Structure

How to determine the diameter of cables is one of key problems in mega steel frame and pre-stressed composite brace structure. Firstly, through analysis of work mechanism of composite brace under horizontal load, the deciding factor of diameter value was found, and furthermore its rule was proposed. Finally, the determination equations were acquired through theoretic deduction and were proved with numerical example. The results indicate that the unbalance in composite brace resulted from antisymmetric load can be eliminated only by antisymmetric way. Thus the diameter value is decided only by antisymmetric horizontal load, and its rule is to keep the balance of composite brace under horizontal load. The influencing factor iterative leveling method can consider the influence from upper and lower floor, and is relatively accurate and feasible.