Experimental Research of Vertically-Loaded RC Joint of Local Transfer from Inclined Column with Different Angle to Beeline-Shaped Short Shear Wall

According to test results of two different angle specimens of local transfer RC joint from inclined column to Beeline-shaped short shear wall under vertical static loads and results of corresponding finite element analysis(ANSYS), fundamental behaviors of the joint are achieved for the change of the angle.The result indicates that there is much difference in the stress distributions of the transfer beam and short shear wall for different angles of inclined column, which shows that the larger angle, the more great tensile force and the earlier crack in the transfer beam and the lower capacity. Otherwise, the angle is smaller, the evener stress distributions in short shear wall, the later crack, the worse degenerate in the transfer beam and the higher capacity.Furthermore, the mechanical behaviors of the joint obviously followed the characteristics of a truss model.     

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.     

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 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.     

Verification and Improvement of the Effectiveness of Seismic Capacity Design Measures of Shear Wall

In order to investigate the effective seismic capacity design measures of shear wall and to realize expected failure modes under strong earthquake,the existing problems in current seismic capacity design measures are pointed out through theoretical analysis.The effectiveness of the measures of Chinese seismic design code is verified by fine finite element dynamic time-history analysis of examples.Improving measures are then put forward and are verified through example analysis.It is shown the bending ductile demand of bottom section of shear wall increases too much based on moment capacity design measures of Chinese seismic design code 2001 in the rigid foundation assumption under rare earthquake action,and its bearing capacity for vertical axis force loses;the shear capacity design measures of current seismic design code would lead to shear failure in the stores above the bottom ductility strengthening area.Some improved bending and shear seismic capacity design measures of shear wall are proposed and are verified to be effective.     

混凝土密柱石膏复合墙板结构性能及简化分析模型

对混凝土密柱石膏复合墙板的水平剪力传递机理进行分析,发现石膏板肋能有效地在混凝土芯柱间传递水平剪力,对复合墙板结构性能有较大影响。在此基础上,提出混凝土密柱石膏复合墙板的等效带缝剪力墙简化分析模型,剪力墙竖缝布置以保证等效带缝剪力墙与复合墙板具有相同弹性抗侧刚度为原则确定。对混凝土密柱石膏复合墙板及等效带缝剪力墙的结构性能进行比较分析表明,混凝土密柱石膏复合墙板与带缝剪力墙受力机理相似,等效带缝剪力墙弹性及塑性阶段都能很好地反映混凝土密柱石膏复合墙板的结构性能。     

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.     

Shear Capacity Calculation Analysis of Reinforced Concrete Beams Based on Truss-arch Model

According to the theory of truss-arch model, the shear mechanism of reinforced concrete beam was analyzed, and formula of shear bearing capacity was proposed. In this formula, softening effect of concrete and the arch function were taken into account, and the coefficients in the formula were amended with experimental data. When the performance difference between the structural material and the original material is huge, the code formula of shear bearing capacity calculation is inapplicable. After the computation, the ratio of the results calculated by truss-arch model theory formula and the results calculated by the current code formula was close to 1, and the standard deviation coefficient and coefficient of variation were smaller than those of standard formula results, and the results calculated by truss-arch model formula were in good agreement with the experimental results. The collected experimental data was calculated with the shear capacity formula in ACI318-08, and the calculation results showed that United States building code was more conservative than the standard of China. The results indicate that the shear bearing capacity formula based on truss-arch model can be used for computation of shear bearing capacity of reinforced concrete beams.     

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.     

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 Researthes of Flexural Strength Coefficient of Short Structure Wall with Unbonded Prestressed Floor System

By means of revered cycle loading tests on the two specimens of short shear wall and unbonded prestressed floor system, the authors analyze the effect on the flexural strength coefficient between walls and beams of cast-in-placed slab and torsion beam. It complements the test results in terms of computer analysis. It brings forward some design method that the flexural strength ratio in this dimension structure system should be amplified than the criterion.     

Research on Design Methods for Reinforced Earth Retaining Wall with Cohesive Backfill

For the stability analysis of the reinforced earth retaining wall with cohesive backfill, this paper assumes that the state of failure surface is circular sliding surface and the bearing capacity is straight line relation with capacity and length of the reinforcement strip. These formulas agree with actual state of the reinforced earth retaining wall with cohesive backfill and result in saving reinforcement material in the design.     

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.     

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.     

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.     

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.     

The Influence of Beam Column Stiffness Ratio of Mine Shaft Tower to Shear Lag Effect

Making use of large finite element analysis software ANSYS, combine with the mine shaft tower actual frame tube structure project to model analysis, by means of concrete performance of mine shaft tower under the effect of horizontal load, come to a conclusion that beam column stiffness ratio has a great influence on shear lag effect. Then analyse the phenomenon of beam column stiffness ratio to shear lag effect, make a comparison on calculated results and simulation analysis results, to move an improved method. It has a great guiding significance for the mine shaft tower structural design.     

考虑滑移和剪切变形的单箱双室组合箱梁剪力滞效应

为准确分析单箱双室组合箱梁的剪力滞效应,考虑钢混凝土的界面滑移效应和钢腹板的剪切变形,针对顶底板和翼板定义不同的剪力滞翘曲位移函数,基于能量变分法推导出单箱双室组合箱梁剪滞效应的控制微分方程及其闭合解。以单箱双室组合箱梁算例为基础,利用该方法分析其剪力滞效应的规律,结果表明：在同时考虑滑移和剪切变形时,组合箱梁的挠度比初等梁理论解大,且其挠度随界面滑移刚度的增大而减小;组合箱梁在均布荷载作用下,滑移量与荷载值近似成正比关系;在相同条件下,钢箱梁底板的剪力滞效应较混凝土顶板显著。     

Calculation models of stress increment of prestressing tendonsusing the deformation of externally prestressed beams

Based on structural deformation analysis, we developed calculation models of externally prestressing tendon stresses increments for simply supported beams on service loads. The Windows program SICPEM for calculating stress increments, based on energy principle, was programmed using the object oriented method. Six beams results, tested by Tan, and the free length of externally straight tendons were recomputed by the program. The ratio of computed results to test results is 0.895, and the standard deviation is 0.013. Furthermore, the free length of externally straight tendons, for which the second order effect can be ignored safely, is ten times beam depth. This coincides with the reference literature.     

Shear Lag Effect of Concrete Box Girders Considered Varying Flange-depths

According to concrete box beam which flanges depth varying along the orientation of cross section, using variational principle of potential energy, new analysis method of shear lag is proposed for single cell concrete box beam. For simply supported girders and cantilever girders, general analysis of varying flange-depths influence on positive and negative shear-lag effect and deflection have be done. It's shown that varying flange-depths have influence both on sectional stress and deflection. Considering the varying flange-depths have effect on the calculation results of up to 15%.