Y形偏心支撑高强钢框架结构抗震性能

在Y形偏心支撑高强钢框架结构抗震性振动台试验的基础上,建立了试验试件的有限元模型,并验证了分析的正确性。设计了一个9层的Y形偏心支撑高强钢框架结构,以耗能梁段长度、耗能梁段腹板高厚比、高跨比为参数,对9层结构进行了非线性动力时程分析,研究了以上参数对结构抗震性能的影响。研究结果表明,改变耗能梁段长度、高跨比对结构层间侧移、耗能梁段性能、框架柱弯矩、耗能能力均有不同程度的影响,对框架柱轴力、基底剪力无显著影响;改变耗能梁段腹板高厚比对结构耗能能力有影响,对结构层间侧移、耗能梁段性能、框架柱受力、基底剪力无显著影响,并给出了相关设计建议。     

Dynamic Response Analysis of High-rise Pile Cap-soil-structure under the Wave and Earthquake Action

Finite element software was used to simulate the internal force and deformation of high-rise pile cap-soil-structure under the wave and earthquake action. Meanwhile, wave force was calculated by using Morison equation, and the mechanical behavior of structure was simulated by inputing horizontal El-Centro wave. Then, the initial state and the state of the largest positive and negative acceleration were selected to study the structure according to the time history curve, and the displacement, bending moment, shear and axial force changes of pile foundation under wave and earthquake action were discussed, which was compared and analyzed with the structural response under the action of earthquakes solely. The result shows that the moment of front row of piles is biggest, and the force of pile bolck is the most dangerous; the axial force of the corner piles is the largest, and one of the center piles is the smallest under the action of wave and earthquake. When the wave forces and seismic forces are in the same direction, the displacement, moment, and shear force of pile bolck will be increased, on the contrary, the displacement, moment, and shear force of pile bolck will be decreased.     

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.     

Inelastic Seismic Response of Ordinary Reinforced Concrete Regular Frames

With an inelastic dynamic analysis program developed by the authors, seismic response analysis of regular RC frames designed to Chinese codes in different earthquake fortification zones are carried out. The results indicate that the displacement responses of structures are improved due to the more rigorous limitation on the inter-story drift under frequent earthquakes in the revised codes. The frames in seismic-intensity-9 zone designed to the former codes and the revised codes form plastic energy-dissipated mechanisms mostly With beam hinges, which can satisfy the requirement of seismic performance expectably. The frame in seismic-intensity-8 zone designed to the former code forms a plastic energy- dissipated mechanisms mostly with column hinges and shows a risk of occurrence of story-sway mechanism, while the frame in seismic-intensity-8 zone designed to the revised codes exhibits a relatively improved seismic performance but still with excessive column hinges, which suggests a need to further increase the column moment amplification measures for this kind of frames. The frame in seismic-intensity-7 zone shows a somewhat improved seismic performance than the frames in seismic-intensity-8 zone, but the protection to columns by the seismic measures is sill insufficient, which indicates that the column moment amplification measures for this kind of frames should be enhanced further.     

Technical Economy Analysis on Selection of Structure About Soldier Pile

Based on silt geological condition, aimed at cantilever pile and pile-anchor, using method of beam on elastic foundation ,through multiple combinations of pile spacing, diameter, embedded-depth at different levels of excavation depth, the impaction is discussed on the greatest displacement, maximum bending moment, the largest shear forces of supporting structure, and in different excavation, bolt locations impact on maximum horizontal displacement, the greatest moment of medial and lateral bending moment, the biggest shear force of pile and the axial force of bolt. By deformation control standards of supporting structure, the law and technically feasible program is found. Then combined with construction method of pile and current quota, technical economy is performed to find the economic plan and give suggestion to the project.     

Seismic Concept Analysis of High-rise Diagrid Tube Structures

In order to study the seismic concept of high-rise diagrid tube-core tube structures,CFST diagrid tube-concrete core tube structures were designed based on typical project.The elastic-plastic time history analysis method is adopted and the components yield order is summarized based on their plastic developing processes.The influences of wall thickness,inclined column cross section and coupling beam height on the components yield order are studied and the distribution of seismic fortification lines between tubes are presented.The main factors exerting influence on structure lateral stiffness are analyzed and the key components of structure lateral stiffness and plastic energy dissipation are achieved.The seismic concept of this structure is discussed considering the three level earthquake fortification criterion and components yield characteristics at last.     

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 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.     

Seismic Performance of Regular RC Frame with Specially Shaped Columns

According to the code and technical regulation,an irregular RC frame with specially shaped columns has been designed,which situated at the area of fortification intensity 8. Subsequently,the nonlinear dynamic analysis has been carried out for the structure by inputting ground motions in two directions. After summing up the calculation results,this paper has examined seismic performance of the structure under the rare seismic actions and given a primary evaluation on the structure to see if it could achieve the predetermined anti-seismic aims. It indicates that the structure designed according to the codes can achieve the predetermined anti-seismic aim under the rare earthquake.     

Axial Force Stiffness Interaction in Seismic Analysis of RC Double Column Bridges

Earthquake induced dynamic axial force in reinforced concrete (RC) bridge bent columns will not only change the yield strength of the columns but also change their stiffness, which is seldom considered by the common lumped plasticity line model. Based on the fiber element model results that taking into account the influence of dynamic axial force on strength and stiffness simultaneously, the axial force stiffness interaction effect on the seismic responses of RC double column bridges was analyzed. The results show that, axial force stiffness interaction has a large effect on the seismic responses of the double column bridge in the elastic range, and it does not alter the ultimate capacity of the columns. Since the stiffness of the columns under compression and tension dynamic axial forces offset each other, the global displacement of bridge bent with equal columns is relatively unaffected by the axial force stiffness interaction, however, the differences of the column member forces are manifest. For the short column controls the global stiffness, the axial force stiffness interaction has significant influences on both the global displacement and member force responses. The influences become larger as the irregularity of the bridge bent increases, so the interaction between axial force and member stiffness should be sufficiently considered in seismic analyses.     

Seismic performance of first floor corner joints of high-rise reinforced concrete frame structure

Crushing risk of corner column will increase substantially due to first floor corner joint shear failure of high-rise reinforced concrete frame structure under bi-directional loading and high axial compressive load caused by earthquake action. Therefore,     

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 Study on a Prestressed Frame of Two Spans Under Unsymmetric Load

By the experimental study on a full-dimensioned prestressed frame of two spans, the relative factors are analyzed such as relative height of equivalent compression zone in critical section, secondary moment, ratio of beam rigidity to column and development of cracks in the top of columns etc., which influence the moment distribution of the post-tensioned prestressed concrete frame from the side of internal force redistribution. It is believed that that the factors of relative height of concrete equivalent compression zone and secondary moment influence the moment modulation in most degree, and ratio of column rigidity to beam also plays a part in the moment modulation to some extent. Second, the plastic joints of frame with excessive spans exit in the span which endure the whole load, at last the whole frame is destroyed because of the destruction of the loading frame, the influence to the non-loading span is little.     

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.     

Study on Seismic Behavior of Edge Slab-column Connection

Under the action of lateral forces and vertical loads, the connection of reinforced concrete slab-column structure will not only transfer significant shear forces, but also unbalanced moment. As to the edge slab-column connection, even if there is no later force, it will also transfer unbalanced moment due to the asymmetry. Currently, most tests and studies focus on interior connections, but there are few tests or studies on edge slab-column connections. A relatively new type of shear reinforcement named shear-stud reinforcement was applied in edge column-slab connections and study on the seismic behavior of these connections was conducted. Tests and finite element analysis of three full-scale reinforced concrete edge slab-column connections subjected to gravity and unbalanced moment were completed in this paper, and main conclusions were as following: the bearing capacity, deformation capacity and seismic behavior of connections reinforced with shear-stud reinforcement are improved; deformation of specimens reinforced with shear-stud reinforcement could meet requirements of current codes; the performance of energy dissipating is as good as the common connections, and has reached the medium ductility level.     

高烈度区斜拉桥横向约束方案优化分析

为了确定强震作用下斜拉桥合理的横向抗震约束体系,以可克达拉大桥为工程背景,采用非线性时程分析法,分析了4种横向约束体系即横向滑动体系、全限位体系、位移相关型减震体系和速度相关型减震体系对强震区大跨度桥梁地震响应的影响,重点对钢阻尼器的屈服荷载和黏滞阻尼器的位置及相关参数进行优化分析,并与其他体系的地震响应进行了对比。结果表明：在强震作用下,对于大跨度桥梁横向滑动体系和全限位体系均不是理想的抗震体系;而在墩梁、塔梁之间设置减隔震装置可以有效减少横桥向的墩梁、塔梁的相对位移及地震剪力和弯矩;然而,从桥梁正常使用的角度来看,塔梁之间布设横向钢阻尼器装置优于黏滞阻尼器装置。     

新型组合梁板连接中板的抗弯性能

在高层建筑结构设计中，由于上部荷载较大或梁的跨度较大，使得梁的截面高度较高，通常会影响建筑的有效层高和建筑的总体高度。为了减小各层梁板结构高度，有效增大各层净高，提出了一种钢箱梁嵌入现浇板的新型组合梁板连接方式。针对这种新型连接方式，对6个钢箱梁混凝土板组合连接区域进行了板承受支座负弯矩的单调加载试验，对比分析了采用钢箱梁嵌入混凝土板组合楼盖与传统栓钉连接组合楼盖中板抵抗支座负弯矩的性能差异；并利用ABAQUS对试件进行了有限元分析。试验与有限元分析结果表明：采用钢箱梁嵌入板连接组合方式，其混凝土板抵抗支座负弯矩的能力与传统连接方式板抵抗支座负弯矩能力没有明显差异。     

柱失效方程中荷载相关特性对承载力抗震设计可靠度的影响

以竖向荷载和水平地震作用组合下的钢筋混凝土柱和钢柱为对象,研究了失效方程中荷载相关特性对柱承载力抗震可靠性的影响。根据现行《混凝土结构设计规范》和《钢结构设计规范》分析了不同柱弯矩轴力相关曲线的特性。结合多个框架结构实例,对比了柱失效方程中荷载相关曲线与规范考虑情形的异同。实例分析表明:水平地震和竖向荷载组合作用下,小偏压RC柱和工字型钢柱的荷载相关曲线与规范考虑的情形较为符合,均近似为负相关的直线;水平地震和竖向荷载组合作用下,大偏压RC柱的荷载相关曲线则与规范考虑的情形有较大出入,存在明显的正相关段部分。在此基础上,考虑失效方程复杂特性,依据已有的荷载和抗力变量概率模型,采用Monte Carlo法分析了水平地震和竖向荷载组合作用下柱的可靠性。结果表明:钢柱和小偏压RC柱的承载力抗震可靠度随轴压力荷载效应比值的变化幅度较小,与规范模式计算结果较接近;大偏压RC柱的承载力抗震可靠度随轴压力荷载效应比值的变化会有较大幅度波动,与规范模式计算结果差异较大;当轴压力荷载效应比值为负时,大偏压RC柱的承载力抗震可靠度会低于规范计算值较多,现行柱可靠性设计方法会偏于不安全。     

Seismic Load Tests on Reinforced Concrete Beam-Column Sandwich Joints with High Shear Stress

Seven reinforced concrete Beam-Column sandwich joint specimens were tested under cyclic load. The performances of these specimens consisting of loads resistance, deflection, ductility, displacement, energy dissipation could satisfy the requirement of structures for seismic design. The phenomena that concrete in joint region was crushed by axial load or eccentric load were never observed,and final failure for a multitude of specimens occurred by shear force. Though a few of performances such as beam bar anchorage capacity were not as well as those of traditional joints ,it is feasible for sandwich joints used while establishing structures.     

考虑剪切变形影响的桩基m法计算理论

考虑桩基的剪切变形影响,利用单广义位移深梁理论,建立了桩基m法的计算方法,导出了水平位移、转角、弯矩和剪力的初参数表达式和无量纲参数函数的统一表达式,根据桩底边界条件建立了初参数解的计算公式;给出了无量纲参数函数随换算深度和弯剪刚度比的变化图形。研究表明,换算深度小于3.0时,弯剪刚度比对无量纲参数函数影响较小,换算深度大于4.0时,弯剪刚度比对无量纲参数函数影响的趋势非常明显,桩基剪切变形的影响程度与桩的边界条件有关。算例结果表明,桩身的剪切变形有增大桩顶水平位移、提高弯矩零点位置、改变弯矩分布特征、扩大桩侧土压力大小等影响。