Arch Axis Optimization of New Type Arch Bridge with Diagonal Web Cables Based on Geometric Nonlinear Mechanical Analysis

There are obvious geometric nonlinear mechanical characteristics in new type arch bridge with diagonal web cables. Meanwhile, the convergence of the existing arch axis iterative optimization method is not good. In order to solve new type arch bridge axis iteration convergence problem considering geometric nonlinear mechanical analysis, an arch axis iteration optimization method was proposed based on the iteration basis finite element model with two hinge arch model in main arch ring. A 600m span arch bridge with diagonal web cables was selected as an example to test the convergence performance and applicability of proposed method. The results showed that the bending moment of proposed method had better distribution along arch span, and it is about 35% smaller in maximum bending moment, 17% smaller in minimum bending moment and 23% smaller in bending strain energy compared to the results of linear iteration optimization method. Convergence analysis results demonstrated that proposed method had better iteration performance than the existing method. Meanwhile, different initial arch axis can converge to stable results.     

Nonlinear Seismic Response Analysis of Long- span CFST Arch Bridge

The non-linear seismic response behavior of concrete filled in steel tube(CFST) arch bridge subjected to synchronous seismic excition and multi-support seismic excitation is studied in this paper.The non-linear seismic response of CFST arch bridge is calculated by time-history analysis method,and the effect of geometric nonlinear to long-span CFST arch bridge is studied.The influence of internal-force and deformence under dead-load,multi-support seismic excitation,etc to nonlinear seismic response behavior of CFST arch bridge is analysed.The result show that the effect of geometric nonlinear to long-span CFST arch bridge is obvious.     

Fuzzy Assessment Method for Seismic Damage of CFST Arch Bridges

In order to investigate the conditions of damage and failure of concrete-filled steel tube(CFST) arch bridges, considering the structural and mechanical characteristics of CFST arch bridges, the dual damage criteria assessment models of the various components based on deformation or strength and energy were developed. The nonlinear seismic response of CFST arch bridges was analyzed by finite element method and the fuzzy evaluation method of seismic damage based on fuzzy theory and analytic hierarchy process was studied. Finally, taking a long-span CFST arch bridge as example, the damage index of the bridge was 0.150, 0.152, 0.172 and 0.318 respectively when the seismic peak acceleration was respectively 0.1g, 0.2g, 0.4g and 0.8g. The results show that the CFST arch bridge is slightly damaged under the earthquake when the seismic peak acceleration is 0.4g, and the bridge is damaged moderately when the peak acceleration is 0.8g.     

Wind Tunnel Tests of Long Span Half - through Arch Bridge Section Model

Wind induced vibration is one of the main control factors in the Long span bridge structure design. The wind tunnel tests for measuring the static wind forces on the bridge girder and the section model wind tunnel dynamic testing for Caiyuanba Yangtze River Bridge in Chongqing are introduced in this paper. The wind tunnel testing for measuring static wind forces and vortex- induced vibration test on the arch are introduced taking account of the influence between two arches. The main contents and outcomes of testing are presented. It is indicated that the bridge girder has excellent wind stability and the arch mechanical characters are rather complicated. The drag force on the hind arch varied a lot because of the font arch interference on the wind flow. The drag force on the hind arch will be negative when two arches are close to each other. It increases with the space of two arches. The results of testing will give the data of buffeting and vortex - induced vibration and flutter analysis of the bridge.     

Full Aero-elastic Bridge Model Design of Long Span Arch Bridge

Aero-elastic model design is the precondition of full bridge aero-elastic model tunnel tests. The full aero-elastic bridge model design of long span arch bridge is discussed. The effect on the model design of different transverse rod space and bend stiff is analyzed in detail. Different scheme need to be designed according to the transverse rod stiff. Considering the changing section dimensional arches, the method of projecting the spatial arches to the plane arches, then designing the plane arches, at last projecting the plane arches to the spatial arches is proposed at first. The results show that the method is effective.     

Research on Seismic Behavior of Top-bear Arch Bridge with Viscoelastic Damping Braces

This paper proposes a new method of structure control that to set damping braces in a top - bear arch bridge. Lumped damping can be introduced to structures to reduce seismic response. The FEM analysis of Nimu bridge which is braced with viscoelastic dampers had done. The results show that the viscoelastic damping braces can remarkably decrease displacement within the arc plane, which is an efficient structure control method.     

Finite Element Analysis of the Contact Stress of the Rotary Hinge in the Rigid Frame Arch Bridge Constructed in a Vertically Downward Rotating Manner

Rotary hinges are temporary joints connecting arch ribs with the abutments of rigid frame arch bridges during the vertically downward rotating construction process.We probed the mechanical properties of a rotary hinge.Its stress distribution was simulated in contact FEM during the vertically downward rotating construction of a rigid frame arch bridge.The results show that nearly the entire structure of the rotary hinge is in a low-stress state with only a minor area in a high-stress state.By strengthening some local structures,rotary hinge construction security could be satisfied by its mechanical properties during vertically downward rotating construction.     

Spatial Interpretation of the Wooden Arch Gallery Bridges in Northeast Fujian from the Perspective of Behavior Space

On the basis of investigating wooden arch gallery bridges in China,perspectives of researchers studying wooden arch gallery bridges in northeast Fujian Province were reviewed,and the innovativeness of researches from the perspectives of cultural geography and significance of wooden arch gallery bridge for the locals’behaviors was proposed.Youxi Village in Qinyang Town,Shouning County,known as the Village of Gallery Bridge,was taken for example to analyze physical,spiritual and social properties of its wooden arch gallery bridge spaces.Wooden arch gallery bridge is an effective boundary point of settlement space,constituting natural ecological spaces and man-made physical spaces of rural settlements.And as a type of building space,wooden arch gallery bridge expands settlement spaces,contributes to settlement cultures,and enriches spiritual connotations of regional cultures.In northeast Fujian,wooden arch gallery bridge is an important social space for the locals’daily life by carrying on living,production and spiritual functions.     

Aerostatic stability analysis of long span half-through arch bridges

The main arch of a long-span arch bridge is a compression member. The static wind loads on the bridge not only causes changes of dynamic characters, but also leads the structure to collapse or buckling. Especially, when the arch bridge has longer span and less lateral braces,its stability is much different from the long span cable-stayed bridges and suspension bridges. This paper takes Chongqing Caiyuanba Yangzi River Bridge as a typical example and conducted the wind section tunnel tests. The displacement response of the bridge is obtained and its yield and static stability mechanism under static wind is analyzed. The results show that those factors, such as initial attack angle of the static wind, material yield strength and the static forces coefficients, have great effects on the aerostatics stability of a long span half-through arch bridge.     

Deformation Monitoring and Its Control in a Shallow buried Large span Tunnel Constructed Using the Pile Beam Arch Method

Deformation monitoring and control measures of a shallow buried large span tunnel constructed using the pile beam arch (PBA) method are described, taking the North Gongti Road Station of Beijing Metro line 10 as an example. Based on the monitoring datum, the crown settlement, convergence, ground settlement of the tunnel and the bridge foundation settlement are analyzed. The results show that (1) the PBA tunneling method can restrain the ground settlement and deformation of a shallow buried large span tunnel; (2) the depth, tunnel span and pilot tunnel construction may influence the deformation of a shallow buried large section tunnel significantly; and, (3) advanced conduit grouting, timely preliminary support and permanent lining construction can reduce the deformation effectively.     

Comparisons of Methods for In-Plane Bearing Capacity Calculation of Two-Hinged Parabolic Steel Arch Under Full-Span and Half-Span Loads

The internal force would vary largely with different load ratio for steel arches under combined full-span with half-span loads. However, most relevant formulas on in-plane stability capacity of steel arches were obtained by studying the stability under a single load. Thus, it lacks full considerations of the applicability of bearing capacity formulas under a combined full-span load with half-span load. To overcome this shortcoming, the two-hinged parabolic steel arch was used to compare the results of bearing capacity of arches with different load ratios, rise-span ratios and sections calculated by several methods, The method proposed in the current Chinese design specification of steel arch structure and the finite element method based on the perfect arch and the consistent imperfect arch were included. The results showed that the method in the specification for designing a steel arch would be conservative with a large ratio of the full-span load to the total loads while unsafe with a large ratio of the half-span load to the total loads.     

宁夏中部干旱带不同跨度双膜拱棚冬季温光环境测试分析

为探究宁夏中部干旱带不同跨度拱棚温湿度、光照强度变化规律,研究选取当地跨度8、10、16、20 m的4座双层棚膜拱棚,利用紫藤连线设备检测相关环境参数。结果表明,温室环境受外界天气影响较大,同样天气条件下4座温室环境参数变化趋势相同,但存在一定差异。在温度方面,随着跨度增加,拱棚内1月平均气温16 m跨度最高,8、12 m次之,10 m最低;在晴天、雪天和阴天3种典型天气里,10 m跨度的全天气温能维持在一个较高的水平。在湿度方面,4种跨度的拱棚均能保持较为适宜的空气湿度（相对湿度40%~70%）。在光照强度方面,4座拱棚内的光照强度均较低,均在晴天、雪天和阴天3种典型天气里呈现出单峰曲线。综合考虑,跨度10 m的拱棚能够在冬季维持较好的温湿度和透光性,适宜在当地推广。     

Elastic Buckling and Critical Load of an Pre- stressing Arch

According to the field theory of additional deformation on pre - stressed configuration , in the paper , the ordinary expression of the governing equation and variational equation of elastic buckling are brought forward . Under the theory system, through lowering dimensions, the governing equation and variational equation for the critical condition solution of elastic buckling of a plane arch are deduced, and the eigenvalues problem of the linear homogeneous differential equations corresponding to the equations are concluded While Abandoning the plane assumption and considering shearing deformation, the linear finite element method arithmetic of bending bar's cross section containing six degree of freedom is given. The process of derivation and calculational results show that, under this system info, the finite element equations of bending bar deduced are accurate and easy to be used to numeric calculations, and the conclusion achieved is more practical.     

Research of Structure Optimization Design for Ten Mile River Landscape Bridge

Guiyang Huaxi district landscape bridge is seven miles the beach driving bearing type reinforced concrete box arch bridge, the design process of conventional arch bridge solutions with less thrust arch bridge to carry on the comparison, the combination of special terrain, geological conditions, finally chose the foundation excavation is small, economical, reasonable structure, less thrust of arch bridge using edge inclined rod and bearing platform consolidation, forming the free cantilever end method better solve the horizontal thrust at arch feet larger, by establishing the structure finite element model, analyzes the static force performance, the results show that the thrust of arch stress performance good, less economically feasible, beautiful appearance, and the scenic spot environment more harmonious.     

Time Effect Experimental Analysis of the Soil Arch Effect of Anti sliding Pile

Soil arching effect is important for stabilizing the soil behind anti sliding pile. The creep of soil mass will inevitably lead to the formation of soil arching, which has time effect. In this analysis, an indoor thrust pile model test is proposed. The characteristics of stress distribution in the soil and the time effect of soil arching behind anti sliding pile are analyzed. The experimental data acquired by the soil pressure cells arranged along the normal direction of the thrust show that soil arching effect is enhanced with the increase of thrust.The thickness of soil arch increases with time.And the data obtained by soil pressure cells arranged along the direction of the thrust show that the horizontal soil arching effect increases and then gradually extends.The scope of stress dispersion has very large growth along the normal direction as time goes on.     

Seismic response of long span arch bridge under spatially variable seismic exicitation

Based on a spatial nonstationary model of seismic ground motion, the seismic acceleration time history are simulated by the wave superposition method. And then taking CaiYuanBa arch bridge in Chongqing as original model , this paper utilizes time history analysis method to analyze the seismic response characteristic of this type of long span arch bridge by support consistent or multi support seismic excitation .The numerical results indicate that the spatial variation of seismic ground motion have significant effect on the response of the arch bridge. Thrust of arch rib and vertical displacement, internal force of arch crown are increased greatly, but most internal forces of stiffener support are reduced.     

用有限元法对拱坝地震动应力分析

利用ANSYS有限元软件动力分析中的谱分析、模态分析功能,对拱坝进行地震动应力分析。主要是基于振型分解反应谱理论对拱坝进行抗震计算。通过此方法对沙牌拱坝进行了实例分析,最终计算结果表明沙牌拱坝满足遭遇7度地震时的抗震强度要求。     

拱板仓气密技术研究

本文介绍了对现有拱板仓进行气密改造时所选用的材料、对仓房有形孔与无形缝的处理技术，并测试了改造后仓房的气密性，在空仓与实仓条件下达到8分钟与4分钟以上的气密效果，为现有拱板仓气密改造提供了一条新路子。     

Research on Coaction of Concrete Cast in place Box ArchRing and Arch Centering

The construction method of concreting layer by layer and segment by segment could reduce the use of steel and save construction cost, when concrete box arch ring was built cast in place with aid of arch centering. According to the simulation of large scal     

Study and Application of High Precision Nonlinear Plane Stress Element

A tangent stiffness matrix for quadrilateral plane stress element under large rotation with small strain is proposed in this paper,The corresponding program based on this theory has been worked out;The computation of examples with analytic values has verified that the element's formulation, its program given in this paper have strong nonlinear computation ability;A nonlinear whole-course analysis of stone arch bridge has been done in this paper.The computations presented preferably a comprehensive understanding of nonlinear characteristics of stone arch bridge with small span and could be beneficial for the engineer designers.