Experimental Study on Seismic Behaviors of Transfer Floor from Inclined Column to Framed Short -leg Shear Wall

According to the pseudo static tests on two specimens of Transfer floor from inclined column to framed short-leg shear wall,which are subjected to the vertical loads and the horizontal cyclic loads,in this paper the stress distributions,final failure model of the specimens,paths of the load transfer and the mechanical behaviors of the transfer beam are studied in detail,the ductility and energy dissipation of the specimens are also specially studied.The results show that this kind of transfer structure can have good seismic behaviors.     

Experimental Analysis on Seismic Behaviors of Inclined Column-shaped and Beam-shaped Transfer Floor

In order to analyse seismic behaviors of inclined column-shaped and beam-shaped transfer floor,the pseudo static testing is carried out,which are subjected to vertical loads and horizontal cyclic loads,respectively on two specimens,including the framed short-leg shear wall inclined column-shaped transfer plane framework and the same dimension beam-shaped transfer frame.The load transfer is direct,inclined column transfer structure can reduce the beam dimension effectively,and it is easier to implement the aseismatic design principles,including "strong column and weak beam,strong shearing and weak bend,stronger nodes".Lateral rigidity of inclined column-shaped transfer stories is large,making it difficult to engender structure weakness stories.If the design is reasonable,inclined column-shaped transfer structure can get better seismic behavior.     

Calculation of Capacity of Vertically Loaded RC Joint of Local Transf er from Square Column to Straight Wall

On the basis of experimental results on four specimens of vertically loaded RC joints of local transfer from square column to straight wall, interaction between the transfer beam and the straight wall above it is analyzed. In the test, the effect of height of armpit on the transfer beam upon the behavior of the joint is specially studied. As a result, determination of the design shear force and shear capacity of the transfer beam and calculation of capacity of the straight wall are suggested, taking into account the effect of shear span ratio of the beam.     

Experimental Research on Steel Tube Confined Concrete Column Ring Beam Joint with Shear Ring under Direct Shear

In this paper,through direct shear tests on 3 steel tube confined concrete column ring beam joints with shear ring,the ultimate capacity,the mechanical mechanism,the sliding of ring beam relative to steel tube and the ultimate failure mode of ring beam were analyzed.The results showed that the ultimate failure mode and the calculation of capacity of ring beam joint awaited further tests and analysis.     

Design Method of Reinforced Concrete Sandwich Beam column Joints

The experimental results of reinforced concrete sandwich beam column joints were studied intensively and finite element method simulation of such joints were performed for the sake of design method.Basic design criterion and computation contents were provided according to failure mode of specimens and other experimental results.And the limits of parameters were proposed based on the analysis of seismic behavior influence factors and comparison of traditional joints and sandwich joints.Hence, formulas of load resistant capacity were acquired by the results of load resistant capacity of specimens and nonlinear finite element method simulation.It is found that three measures should be taken for sandwich joints in order to reach demanded ductility and load resistant capability.Firstly, several parameters should be limited, including shear compression ratio, axial load ratio, ratio of beam concrete strength to column concrete strength, and minimal amount of transverse reinforcement of joint.Secondly, shear load resistant capacity and axial compressive load resistant capacity should be computed to ensure load resistant capability of joint, and essential strengthen measures could be applied if necessary.Thirdly, appropriate construction details should be taken to avoid reducing of beam bar anchorage capacity.     

Mechanical Characteristics of Earthquake-Resistant Reinforced Concrete Frame Joints

On the basis of analysis and induction of experimental results on earthquake-resistant frame joint both at home and abroad, it is clearly pointed out that the mechanical characteristics of the joint in which shear failure may occur after yielding of longitudinal rebars at the beam end or at the column end are classified into three types, i. e ., diagonal tension, diagonal compression and a combination of diagonal tension and diagonal compression. A region of these three types of mechanical characteristics in the coordinates composed of relative shear force and relative ratio of transverse reinforcement is given, and the variation law and the corresponding reasons for the mechanical behaviors with the relative transverse reinforcement are analysed.     

Behavior of dendriform connections of concretefilled steel rectangular tubes

Dendriform connections of concrete filled steel rectangular tubes (CFSRT) are composed of a bifurcated column and double cruciform beam column connections. A 3 D nonlinear finite element analysis (FEA) which considers all nonlinear effects of materials, geometry and contact interfaces is established. Analysis of the FEA results show that the load displacement curves at the ends of the beam and hysteretic curves obtained experimentally and via FEA agreed with each other. The stiffener transfers the tension compression stress efficiently, the middle hole has little influence on the stress transfer, and the compressive zone of the core concrete under repeated loading has a greater contribution to the compression stress transfer.     

Experimental Research on the Behavior of Direct Anchoring Beam-wider-than-wall Joint

Based on the elastic finite element analysis of the RC beam-wider-than-wall joint, two large-scale specimens of the direct anchoring beam-wider-than-wall joint are designed to test the joint behavior. The stresses and slips of longitudinal bars in the beam, load-bearing capacity and destruction form are observed and analyzed. The analysis and test results show that: The wide beam should be extended through into the wall for some length to make the flexural stress uniform along beam section width, thus the beam's bearing capacity can be achieved. The anchorage condition of the upper longitudinal bar in the beam outside the wall's width is poor, thus the anchorage length prescribed in the current CODE is not enough to ensure the bearing capacity and ductility of joints. The beam stirrups are very important to the anchorage of the upper longitudinal bar in the beam outside the wall's width. If the quantity of the beam stirrups is not enough, the wide beam in the joint area would have more cracks which decrease the bearing capacity and ductility of joints. Finally, a novel spatial truss mechanism model for the beam-wider-than-wall joint is put forward.     

X形配筋增强高强钢筋异形柱边节点抗震性能试验研究

通过对核心区应用X形配筋增强的高强钢筋异形柱边节点和同等条件下未被增强的高强钢筋异形柱边节点进行拟静力试验研究,对比分析异形柱边节点的破坏特征、滞回曲线、承载能力、位移及延性、刚度退化、耗能能力等抗震性能指标。研究结果表明,配置HRB500高强钢筋异形柱边节点比配置600 MPa级的边节点承载能低,但滞回性能好,变形能力强,刚度退化推迟,耗能能力强;在核心区加入X形配筋,均可以改善高强钢筋异形柱边节点的破坏特征,使边节点抗剪能力、变形能力、耗能能力增强,刚度退化推迟,提高异形柱边节点抗震性能,配置HRB500高强钢筋的试件核心区应用X形配筋加强后抗震性能提高效果更好。     

Study of Cracks on Rubber Concrete Beams Based on Fractal Theory

The flexural performances of a rubber concrete beam and a ordinary concrete beam are studied under concentrated load through the experiment. The influences of the content of the rubber powder in the rubber concrete beam on the bearing capacity and the crack width of beams are analyzed. The experimental results show that the crack distributions on two beam surfaces possess the characteristics of self-similar in statistical sense. The maximum crack width of the rubber concrete beam is less than that of the ordinary concrete beam under the same load level. The performance of anti-crack of the concrete beam is improved by adding the crumb rubber. Using the fractal theory, the fractal dimension values of the surface crack of the beams under different load grades are calculated and the relationship between the fractal dimension and the maximum crack width of the surface cracks is established.     

Experimental Analysis on Shear Strengthening Capacity of Secondary Dapped end Beams

Because section steel can only be extended to the edge of the support, when a simple support RC beam is reinforced by bonded section steel, a notch comes into being at the end of the beam which is called a secondary dapped end beam, making the stress state of the beam more complex. Through experimental analysis on 21 dapped end beam specimens shear reinforced by steel plate bonded, the deformation process, performing characteristics and failure mechanism of the specimens were investigated. The result shows that two steel bonded forms, including horizontal steel plate and oblique steel plate with angle 45° bonded, delay the appearance of cracks significantly and improve the maximum bearing capacity by 102% and 93%. Due to the impact of stress concentration at the notch, the main modes of damage include concrete tensile or shear failure with the result of bonding failure of a steel plate. By changing the width of steel plates and analyzing different reinforcement effects, formula of bearing capacity of shear reinforcement was proposed based on the method of truss analogue, which provides a reference for engineering application.     

Experimental and Numerical Analysis on Rupture of Rock Bridge with Non-Coplanar Intermittent Joints Under Direct Shear

By using servo control shear loading system, specimens with non-coplanar rock-like intermittent joints were tested by the way of forward and reverse direct shear, rupture mechanism and shearing law for rock bridge with non-coplanar intermittent joints were studied under direct shear. The experimental studies showed that five apparent stages are presented in the process of rock bridge rupture under direct shear, which are linear elastic stage, initiation and extension of crack, fracture and transfixion of rock bridge, climbing and occlusion of shear plane and residual friction. Rock bridge presented profile fracture plane under forward direct shear. While under reverse direct shear, band form fracture plane is showed which penetrated along with the direction of forward shear, and the shear strength of initiation and peak shear strength under reverse direct shear are bigger than that under forward shear. Crack angle, normal stress and lap proportion among adjacent joint are the main factors that influence the initiation strength and peak shear strength. The FLAC 3D simulation for the process of non-coplanar intermittent joints rock bridge rupture and formation of shear rupture surface under forward and reverse direct shear was conducted. The results of numerical simulation agreed well with those of experiment. The simulation results revealed tension crack failure of non-coplanar intermittent joints rock bridge and shear yielding mechanism of fracture plane.     

Stability Behavior of Shuttle-Shaped Steel Lattice Columns With Bending Moment

The stability behavior of shuttle-shaped steel lattice columns subject to combined axial force and bending moment was examined through elastic buckling analysis and geometrically and materially nonlinear analysis. Firstly, the concept of section stiffness variation ratio is proposed for shuttle-shaped lattice columns and the elastic buckling behavior is discussed. Then, the effect of bending moment on the stability behavior of lattice columns is investigated, with the emphasis on the development of axial stress, bending stress and shear stress. The influence of column component spacing and diaphragm thickness on the stability bearing capacity is also analyzed. It is shown that the elastic buckling mode of the lattice column is dependent on its section stiffness variation ratio; for lattice columns with C-shaped buckling mode, the reduction in stability bearing capacity caused by bending moment is smaller than that of columns with S-shaped buckling mode; the maximum stability bearing capacity of the lattice column can be achieved by adjusting the column component spacing, and the spacing corresponding to the maximum capacity is basically consistent with the critical spacing for transformation of C-shaped buckling mode and S-shaped mode; and it is more effective to increase the thickness of columns with S-shaped buckling mode to get larger bearing capacity.     

Experimental Investigation on Purification Process of P-xylene in an Inclined Column Crystallizer

With the p-xylene, o-xylene simple eutectic system, the purification process of organic materials in an inclined column crystallizer at total reflux and steady state was investigated. The results indicate that inclined column crystallizer has strong adaptability for purifying p-xylene, the product purity can easily exceed 99.9% at the range of feed composition among 65.0%-85.0% and internal stirring speed among 6-10 r/min, the axial dispersion model satisfactorily explains the concentration distribution profile in inclined column crystallizer.     

Experimental Study on the Beam Bars Detail in Exterior Short Pier Shear Wall Joints

By experiment of the beam bars in exterior short pier shear wall joints,the anchorage performance of the beam bars in joints on the action of low cyclic load have been studied to attest if the beam bars in exterior short pier shear wall joints can sufficed with the demanding of anchorage intensity and anchorage rigidity, when the anchorage of beam bars satisfy the requirement of the code.     

Effect of thermal radiation on thermal flow field in inclined tunnel

The thermal radiation is the main factor affecting internal thermal flow field in a tunnel. This paper studies on two open ends of a channel inclined with angles of 10°, 20° and 30° by experiments and numerical simulations. The experimental data agree well with the predicted results by using Large Eddy Simulation (LES) to solve N-S equations driven by the buoyancy flow. And the influence of thermal radiation on thermal flow field of tunnel with inclination angles from 10° to 30° at same heat source is obtained by comparing the experiment results and numerical resolutions of coupled with radiation model and without radiation model. Thermal radiation makes temperature near the upper wall of tunnel drop, and the influence of thermal radiation on bottom end of tunnel declines with the inclination angle increasing. However, the inclination angle has a little effect on temperature near the ceiling of the top end of tunnel. Simultaneously, the higher temperature zone leaning to the top end due to the thermal radiation is obtained, and the temperature at the bottom of the upper part of the tunnel increases. The findings of the study are important references for theory research of thermal flow field in inclined tunnels.     

TENTATIVE INVESTIGATION OF THE BEHAVIOR OF REINFORCED CONCRETE FRAME CORNER JOINTS UNDER LOW CYCLE LOADING

In this pager, four full-scale corner joint assemblies of reinforced concrete frame beam and column with different detail structure are tested under low cycle loading, The process of damage development and the characteristics of break of the assemblies in the course of alternately increasing positive and negative bending deformation are learned Strength, stiffness and ductility of assemblies and the various regulations of energy consumption are also studied. Compared with these properties, the anti-seismic behavior is tentatively commented. Besides, the test results of the strain distribution of beam and column longitudinal bars and stress state of joint stirrups are analyzed.     

各向异性砂土剪切带角度的理论分析

针对平面应变条件下各向异性砂土剪切带角度的试验规律,采用传统的3种理论和分叉理论进行对比分析。将平面应变条件下剪切带角度的试验结果按照传统3种理论整理发现,尽管传统3种理论可以估算同种砂剪切带角度的极小、中间和极大值,但无法解释其各向异性规律。砂土在平面应变条件下破坏时会产生明显的剪切带,当剪切带方向和砂土沉积面方向接近时,会较早诱发剪切带的产生,使材料强度降低,造成了平面应变条件下各向异性强度规律明显不同于常规三轴条件下的试验规律,采用分叉理论结合各向异性模型则可以有效解释这个规律。随砂土沉积面角度的变化,模型可以从细观角度解释常规三轴条件下剪切带角度的单调变化的试验规律,结合分叉理论可以描述平面应变条件下其先减小然后增大的规律。通过几种理论对比分析表明,模型结合分叉理论不但能够描述多种应力状态下的平面应变和常规三轴应力条件下剪切带角度表现的不同规律,而且能够从细观角度解释其各向异性成因。     

Experimental Investigation of "Column with Weaker Beam" Frame and "Column with Equally Strong Beam" Frame

By the way of experiment and analysis of two "one story and one bay" reinforced concrete frames, namely a "beam with weaker column" frame and a "column with equally strong beam" frame, the features of internal force redistribution are investigated and an elementary comparison about bending moment redistribution of three kinds of frames namely the "column with weaker beam", "beam with weaker column" and "column with equally strong beam" is given. Through this comparison, the objective existence of such "three kinds of frame" is proven, the moment redistribution is different for each frame and for the moment modulation, the elastic moment diagram and the difference of the internal force redistribution in different frames should be considered together.     

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.