不同加载方式SIP墙体的抗剪性能

以3种不同的单向加载方式对以木质OSB覆面的SIP墙体进行侧向加载实验,对比分析3种加载方式下SIP墙体的破坏形式及这3种加载方式对墙体抗剪性能参数的影响,结果表明:3种加载方式得到的墙体的抗剪性能指标有所差异,其中,采用ISO22452加载协议,即对墙体施加持续增加载荷的加载方式所得到的极限承载力最大、极限位移和延性系数居中,分别为46.06 kN、71.83 mm、3.31;采用ASTM E72-05加载时极限承载力居中、极限位移及延性系数最大,分别为:40.66 kN、76.97 mm、4.07。采用ASTM E564-06加载,即对墙体施加阶段载荷并使阶段目标载荷持续作用一段时间的方式,所得到的极限承载力、极限位移及延性系数最小,分别为37.73 kN、54.92 mm、2.91;3种加载方式对墙体破坏形式的影响不大。     

Effects of Infill Walls in Frame Structures under Frequent Earthquake:Revelation from Wenchuan Earthquake

Based on a three-story RC frame, the analysis of the structure with various layouts of infill walls under frequent earthquake was conducted. The results indicate that when the infill walls and their different layouts are incorporated into the structural model, the seismic performance, such as dynamic properties, characteristics of regularity, and internal force distributions would change significantly. It should be also mentioned that because of the constraint of infill walls, the sum of moments at column ends is much larger than that at beam ends at the frame column-beam joints. It is suggested that infill walls should be adequately considered in the mechanical models during seismic analysis.     

Influence Factors Study of Bearing Capacity of T Shaped RC Steel Reinforced Concrete Short-pier Shell Wall

In order to ensure that the T shaped steel reinforced concrete short-pier shear wall ductile shear failure occurs, the failure mechanism on the basis of experimental research, using ANSYS finite element analysis software to simulate the failure mode. In the process of analysis considered the influence factors of horizontal steel reinforcement ratio, concrete strength, axial compression ratio and the content of steel. The results show: the level of reinforced volume reinforcement ratio, concrete strength and the content of steel can obviously change the the bearing capacity and ductility of components.     

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.     

RC加气混凝土砌块组合墙加固框架抗震性能试验研究

RC加气混凝土砌块组合墙（简称组合墙）是由混凝土梁柱网格与加气混凝土砌块组合形成的一种轻型网格式抗震墙,可用于框架结构的抗震加固。笔者进行了1/2比例空框架试件、组合墙试件和组合墙加固框架试件的低周反复荷载试验,分析了各试件的主要破坏过程,对比了组合墙加固框架前后试件承载能力、刚度等抗震性能变化。试验结果及分析表明：组合墙加固框架后承载力、抗侧刚度有较大幅度提高,中大震及大震阶段其承载力、等效刚度约为空框架和组合墙单独受力之和的0.9倍,两者具有良好的协同工作性能;加固试件的破坏过程基本上遵循填充砌块混凝土框格外框架的破坏顺序,能够发挥组合墙多重抗震防线的特点,采用RC加气混凝土砌块组合墙加固框架是一种较为经济实用的加固方法。     

Shear Ductility of Hybrid Fiber Reinforced High Performance Concrete Deep Beams

The shear tests were conducted on 18 different groups of deep beams with steel fiber and polypropylene fiber and two groups high performance concrete deep beams without fiber according to the orthogonal experimental design. By a definition of shear ductility index shear ductility of deep beams was analyzed quantitatively. The influence of six factors on improving shear ductility of deep beams was compared by direct-viewing analysis of the orthogonal experiment. The contributory factors such as the species of steel fiber, the volume fraction of steel fiber, the length/diameter aspect ratio of steel fiber, the volume fraction of polypropylene fiber, the ratio of web horizontal reinforcement and the ratio of web vertical reinforcement were analyzed. Results show that the volume fraction of steel fiber plays the most important role in improving shear ductility of deep beams exceeding the ratio of web horizontal reinforcement and the ratio of web vertical reinforcement, whereas species of steel fiber has minimum effect. Hybrid fiber can be used to greatly increase shear ductility of deep beams and shear ductility is at the most increased by 40.7% although it can not change the brittleness of shear damage. The full-range shear behaviors of deep beams through ABAQUS are analyzed and the calculated results are in good agreement with test results.     

CFRP筋钢筋混凝土剪力墙自复位性能试验研究

通过对1片钢筋混凝土剪力墙和4片配有碳纤维增强聚合物(CFRP)筋的剪力墙的低周反复荷载试验,在分析试验中测得的裂缝宽度、裂缝的发展和分布形态、侧向变形的基础上,研究了在钢筋混凝土剪力墙的适当位置部分或全部配置CFRP筋对剪力墙的残余裂缝和残余变形等自复位性能的影响规律。研究结果表明:与普通钢筋混凝土剪力墙相比,配有CFRP筋的剪力墙的开裂荷载较低,裂缝较多,裂缝分布分布范围较广,墙体的最大裂缝宽度、残余裂缝宽度和侧向残余变形分别降低了60%、70%和90%,说明在剪力墙中合理配置CFRP筋能使剪力墙具有优异的自复位性能。     

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.     

Seismic Characteristics of Widened Beam Flange Joints

In order to analyze the seismic behavior of widened beam flange joints, 16 specimens were derived from finite element models base on experiments. The effects of some parameters, such as the increased width and length, on ultimate load and ductility performance of joints were further discussed with ANSYS finite element method. According to specimen failure phenomenon of both experiment and finite element method, the weak link of the joints was found and the cracking possibility was evaluated. A theoretical analysis of the fracture mechanism of widened beam flange connection was conducted. In addition, design method of widened beam flange parameters was introduced, which will offer valuable information and reference for seismic design in steel frame joints.     

Seismic Tests and Pushover Analysis of Spatial RC Frame-Shear Wall Structures

Pseudo-static tests of three one-storey spatial RC frame-shear wall structures with floor slabs were conducted to investigate their failure modes and hysteretic behaviors. The test results were compared with those of pushover analysis. It is shown that: 1) damage of the frame beams occurs later and is less than that of the shear wall and the frame columns; 2) damage of the floor slabs under lateral loading is significant in regions close to the shear wall, and tensile stresses of slabs' steel bars in these regions are much larger; 3) in comparison with the case that the floor slabs are neglected, the maximum lateral load that a frame-shear wall structure can bear is larger in the case that the floor slabs are taken into account, and the contribution ratio of the shear wall also increases; 4) shear forces carried by the frame columns with identical cross sections and reinforcement details but located at different positions are close to each other on the whole.     

Interaction Working Behavior About the Internal and External Wall of Foam in place Cavity Wall

In order to study the stability of foam in place cavity wall, the capacity of reinforced concrete strip ear and tie involving in cavity wall deformation, the broken shapes and mechanical performance of the cavity wall, the effective measures was seaked to improve deformation capacity and overall performance of the cavity wall.13 patches of cavity wall and 1 patch of solid wall were built and seismic tests of which were carried out.The lnfluence of some constructional measures on mechanical behavior and deformation properties of the wall and vertical pressure and insulation layer thickness on the relative displacement difference of the internal and external wall of foam in place cavity wall was analyzed.Finally, the capability of reinforced concrete strip ear and tie working interactively between the internal and external wall of foam in place cavity wall was analyzed.It is found that deformation capacity of the cavity wall is improved efficiently with constructional column and the high bonding strength, shearing strength and pressure strength of foam in place insulating mortar have certainly a positive influence on the bearing capacity of the wall.The reinforced concrete strip ears play the leading role in reinforcing connection of the internal and external wall of foam in place cavity wall and guaranteeing out plane stability of the external wall.When walls crack seriously, the ties can play an important role in supporting and drawing the wall and preventing wall collapse.Furthermore, the reinforced concrete strip ears and ties which are the main construction measures to coordinate the internal and external wall work together perform a great variety of tasks.Therefore, the reinforced concrete strip ears and ties should be designed rationally to guarantee playing their respective roles.     

Experimental study on seismic behavior of beam-column sandwich joints with big beam-column eccentricity

Three specimens of sandwich joints with eccentricity being larger than a quarter of the column width in middle floor of frame are designed and loaded under cyclic loading. Their shear capacity, failure modes, and ductility, as well as energy dissipation are analyzed. The results show that the performance of sandwich joints with big eccentricity is good under cyclic loading. X-type reinforcements can be used to substitute for stirrups in the joint to bear shear forces. But the anchorage of longitudinal bars of beams in eccentric sandwich joints is relatively weak. Comparing to sandwich joints without eccentricity, the column longitudinal bars near the sandwich joints with big eccentricity are vulnerable to sudden change of strain.     

Numerical Simulations and Design Method of Coupled Wall System with FRC Coupling Beams

Using the software, ABAQUS, accurate simulations of seismic behavior of 2 coupled wall specimens and 2 cantilever structure wall specimens using high performance fiber reinforced concrete (FRC) in plastic hinge under quasi static cyclic loading were carried out. The analysis model proves to be effective with the accordance between results of computation and experiment, then it can be used to analyze the seismic behavior of coupled wall system with FRC coupling beams. By using the verified numerical model, the ability of FRC coupling beams instead of RC coupling beams to provide acceptable performance was discussed. In addition, the impact of coupling ratio on seismic behavior of coupled walls was studied. The results show that coupled walls in which FRC coupling beams are used instead of traditional RC beams have good energy dissipation and ductility, and its initial stiffness is increased and stiffness degradation is slow. And as the coupling ratio of coupled wall structures increases, the stiffness and strength increase. But if the coupling ratio is too large, the ductility and energy dissipation capacity will be significantly reduced.     

Shear Performance of Steel Plate with Trilateral Constrained

The load carrying test for four steel plate shear walls specimens with various ratio of width thickness are carried out so as to test the failure mode and the shear strength of steel plate with trilateral constrained, and the lateral stiffness and the buckling mode are investigated in the test. The result indicates that the ratio of width thickness of steel plate exerts effects on the shear carrying capacity and failure mode; the buckling of steel plate does not have lateral stiffness. Based on the failure mode of steel plate, the computation model of lateral performance is presented by theoretical analysis. The restraining stiffness of double angle and the buckling restrained stiffness of steel plate are the important design conditions. Formulae to determine the elastic lateral stiffness and the angle type is proposed, which can be used in the preliminary design of steel plate with trilateral constrained.     

Research on Deformation Equation and Dynamic Properties of Hybrid Structure

Based on the principle of interactive analysis,the deformation equation of hybrid structure which contains rigid character value is established using the analysis of the frame - shear wall structure for reference, considering the rigid zone between concrete beam and concrete - tube, the shear deformation of concrete - tube, axial deformation of steel frames and semi - rigid connection between steel columns and concrete beams. Assuming the hybrid structure to be a continuous elastic structure with infinite degree of freedom, a free vibration equation has been built and the formula for calculating free vibration period has been deduced. The influences of various parameters to the coefficient of free vibration period relating to rigid character value are discussed according to some diagrams. It is shown that the rigid zone can lessen the free vibration period but the shear deformation of concrete - tube, axial deformation of steel frames, and the semi -rigid connection between steel columns and concrete beams can enhance the free vibration period.     

Experimental Study on, Small Span to Depth Ratio Coupling Beams withNew Reinforcement mewt Scheme and Design Method

Coupling beams combining two coupled walls are the primarily energy dissipating elements in the coupled walls and play a key role in improving ductility. It is proved by the test outcome at home and abroad that the shear failure happening early cannot be     

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.     

Experimental Analysis of the Behavior of Steel Plate-masonry Composite Wall-beams

When steel plate-masonry composite structure used in the existing masonry structure with load bearing walls is removed for a large space, composite action should be considered between the beam and the supported masonry wall due to the arch effect formed in the supported wall. In order to investigate the working mechanism, failure mode, and load-carrying capacity, strain distribution in critical sections and mid-span defcection of this type of composite wall-beam, five steel plate-masonry wall-beams were tested under concentrated loads and analyzed, which considered variables of height-span-ratio of supported masonry wall, height-span-ratio of composite beam and thickness of steel plate. The results show that steel plate-masonry composite wall-beam starts failure from the masonry located at the line between loading point and supporting point; strain distribution of steel plate along section height meets the plane section assumption; the height-span-ratio of supported wall can directly influence the failure mode of masonry wall, buckling load corresponding to steel plate experiencing local buckling and ultimate load of tested specimens; the reasonable height of supported masonry wall is beneficial to the formation of composite action between supported masonry wall and composite beam, and the excessive high masonry wall will reduce the ultimate load of the tested specimen. Finally, the reasonable range for height-span-ratio of supported masonry wall was presented, and the proposed value representing the flexural stiffness of the steel plate-composite beam relative to the in-plane stiffness of the supported masonry wall was at least more than 79.     

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.     

Application of Multi-vertical-line-element Model of RC Walls and Discussion on IT

The inelastic dynamic response analysis program for frame-shear wall structures developed by the authors is introduced firstly, in which the multi-vertical-line-element model was adopted for shear walls and the refined single-component model was used for beams and columns in frame.By analyzing three-story structural models tested in shaking-table in a famous foreign research institute, the validity of the modeling of shear wall in the program was verified. The analytical results indicate that the inelastic dynamic responseof shear walls under random ground motion input can be predicted effectively withthe program. Finally, with the preliminary discussion of some key points in modeling of shear wall, some suggestions areput forward for further improving and refining the multi-vertical-line-element model.