Self-anchored Cable-stayed Suspension Bridge Research Articles

Displacement-based Mode Pushover Analysis of Self-anchored Cable-stayed Suspension Bridge

As being a typical multi-freedom degree system structure, self-anchored cablestayed suspension bridge is significantly affected by higher modes in the earthquake response. Traditional force-based pushover analysis of reverse triangle or uniform distribution patterns will lead* to a certain error for the results of pushover analysis of self-anchored cable-stayed suspension bridge. An improved method of displacement-based mode pushover analysis is presented in this paper by combining the two stage horizontal displacement pattern with mode pushover. This improved method can take the contributions of higher modes into account. And the applicability of the method can be verified commendably by the selected examples. Traditional force-based pushover analysis considers the seismic load is equivalent to lateral load. And it judges whether the deformation ability of the structure and component can meet the need of design and use function by analysing nonlinear response of structures under the monotonic increasing horizontal lateral load applied to the structure with a certain distribution mode. The selection of the lateral load distribution mode can directly affect the analysis results of the pushover method on the seismic performance of whole structure in traditional force-based pushover analysis. Moreover, the problem of stiffness degradation after failure is not taken into account in this traditional wide application method. Seismic hazard, experiment and theoretical analysis indicate structural collapse is mainly due to the lack of deformation capacity and energy dissipation capacity during severer earthquake. In this case, the deformation capacity and the displacement response of structure will have an certain impact on the damage degree of structural members. Therefore, it is more reasonable to use displacement control on structural seismic response during severer earthquake[4]. Compared with the traditional force-based design, the displacement of structure can reflect the nonlinear reactive state more during severer earthquake, it also can control the behavior of structure better in earthquake. Consequently, the displacement-based seismic design method has been greatly developed[5-10]. There are three commonly used displacement-based seismic design method: ductility factor design, capacity spectrum and direct displacement-based design method. The basic thought of displacement-based mode pushover analysis is as follows: first, put monotonic increasing lateral displacement to bear on structure directly according to a certain horizontal displacement distribution mode, second, the final failure pattern of structure is obtained by pushover the structure to the target displacement, after that, whether the deformation ability of structure and component can meet the need of design and use function can be analyzed.

A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes.

Design analysis of the optimum configuration of self-anchored cable-stayed suspension bridges

This paper describes a formulation to predict optimum post-tensioning forces and cable dimensioning for self-anchored cable-stayed suspension bridges. The analysis is developed with respect to both dead and live load configurations, taking into account design constrains concerning serviceability and ultimate limit states. In particular, under dead loads, the analysis is developed with the purpose to calculate the post-tensioning cable forces to achieve minimum deflections for both girder and pylons. Moreover, under live loads, for each cable elements, the lowest required cross-section area is determined, which verifies prescriptions, under ultimate or serviceability limit states, on maximum allowable stresses and bridge deflections. The final configuration is obtained by means of an iterative procedure, which leads to a progressive definition of the stay, hanger and main cable characteristics, concerning both post-tensioning cable stresses and cross-sections. The design procedure is developed in the framework of a FE modeling, by using a refined formulation of the bridge components, taking into account of geometric nonlinearities involved in the bridge components. The results demonstrate that the proposed method can be easily utilized to predict the cable dimensioning also in the framework of long span bridge structures, in which typically more complexities are expected in view of the large number of variables involved in the design analysis.

Effect of Viscous Damper Position for Isolation System of Self-Anchored Cable-Stayed Suspension Bridge

Larger displacement and inter-force response of the structure will be produced when self-anchored cable-stayed suspension bridge in longitudinal earthquake. For the isolation system of self-anchored cable-stayed suspension bridge, whose main tower is set the lead core rubber isolation bearing. This essay does the nonlinear time history analysis under the longitudinal earthquake about the isolation system when the viscous damper is put in different location. Analysis results show that inter-force and displacement of control section and control node are reduced greatly in hybrid vibration control. The result is obvious when the viscous damper is set both in the main tower, the side block and only in the main tower.

Effect of LRB Position for Vibration Reduction System of Self-Anchored Cable-Stayed Suspension Bridge

Larger displacement and inter-force response of the structure will be produced when self-anchored cable-stayed suspension bridge in longitudinal earthquake. Engineering practice proved that the viscous damper has obviously damping effect for structure. For the vibration reduction system of self-anchored cable-stayed suspension bridge, whose main tower is set viscous damper. This essay does the nonlinear time history analysis under the longitudinal earthquake about the vibration reduction system that considering the LRB putted in different location. Compared with the damping system that only set viscous damper, analysis results show that inter-force and displacement of control section and control node are reduced greatly in hybrid vibration control.

Hybrid Vibration Control of Self-Anchored Cable-Stayed Suspension Bridge

Larger displacement and inter-force response of the structure will be produced when self-anchored cable-stayed suspension bridge in longitudinal earthquake. The optimized layout of viscous damper is done for self-anchored cable-stayed suspension bridge with the lead rubber bearings in the main tower, moreover, the nonlinear time-history analysis in the longitudinal seismic input be made. Comparing the analysis results above between the scheme with viscous damper and the scheme without isolation measures, analysis results show that inter-force and displacement of control section and control node are reduced greatly in hybrid vibration control.

Dynamic Model Scheme Optimization Based on Fuzzy Decision Theory of Self-Anchored Cable-Stayed Suspension Bridge

Based on fuzzy decision theory, multi objective fuzzy optimization is done for three dynamic model scheme of self-anchored cable-stayed suspension bridge. Combining the fuzzy decision method with engineering practice and using two comparison theory solves the problem of quantifying the qualitative indexes. Comparison results show that it is more reasonable to place viscous dampers between main tower and girder, with longitudinal displacement on mid-span of girder on the same time. This method can provide a reference for structure selection in practical conceptual design phase.

Analysis of Longitudinal Seismic Isolation of Self-Anchored Cable-Stayed Suspension Bridge Based on Lead Rubber Bearing

Based on the background of Dalian Bay Cross-Sea Bridge project, some plans with settings of lead-rubber bearing among side pier, tower and stiffening girder have been analyzed under longitudinal seismic input using the favorable shearing property of laminated rubber, damping characteristics of lead. Analysis results show that the displacement and force of controlling node and section have been reduced. The effective isolated device is obvious.

Study of Vertical Seismic Isolation of Self-Anchored Cable-Stayed Suspension Bridge Based on Lead Rubber Bearing

Based on the background of Dalian Bay Cross-Sea Bridge project, some plans with settings of lead-rubber bearing among side pier, tower and stiffening girder have been analyzed under vertical seismic input using the favorable shearing property of laminated rubber, damping characteristics of lead and reasonable parameters (yield force and stiffness). Analysis results show that the displacement of controlling node and force of controlling section have been reduced.

Development of Self-Anchored Cable-Stayed Suspension Bridge in China

Self-anchored cable-stayed suspension bridge has highly competitive in large-span bridge scheme selection due to it combines both stress characteristics and structural characteristics of cable-stayed bridge and self-anchored suspension bridge. This paper focuses on the development of self-anchored and earth-anchored cable-stayed suspension bridge in China, lists the bidding scheme and the actual project of this type bridges.

Theoretical Study on Space Coupling Free Vibration Analysis of Self-Anchored Cable-Stayed Suspension Bridge

Based on Large-displacement Non-linear Elastic Generalized Variational Principle, coupling effect of axial and flexural action, shearing strain energy, torsional strain energy of stiffening girder were considered, the large-displacement incomplete generalized potential energy functional of space coupling free vibration of a three-span self-anchored cable-stayed suspension bridge was presented. By constraint variation, fundamental differential equations of vertical flexural vibration, lateral flexural vibration, longitudinal vibration and torisional vibration were formulated, also presented the equations for the main tower with respect to longitudinal and lateral vibration. The linear free vibration differential equation was obtained when the nonlinear items were discarded. This approach provides theoretical basis for analysis of natural vibration character of self-anchored cable-stayed suspension bridges.

Dynamic Isolation Model Scheme Optimization Based on Fuzzy Decision Theory of Self-Anchored Cable-Stayed Suspension Bridge

Based on fuzzy decision theory, multi objective fuzzy optimization is done for the dynamic isolation model scheme of self-anchored cable-stayed suspension bridge. Using two comparison theory solves the problem of quantifying the qualitative indexes and distinguish the concepts of importance and superiority. Combining the fuzzy decision method with engineering practice and using the results of five cases are proposed for multi objective fuzzy optimization. Comparison results show that it is more reasonable to place lead rubber bearings not only between pier and girder, but also main tower and girder, with viscous dampers between main tower and girder on the same time. This method can provide a reference for structure selection in practical conceptual design phase.

Study on Boundary Conditions of the Natural Vibrations for Self-Anchored Cable-Stayed Suspension Bridges

The study of the natural vibrations is the basis of risk evaluation. Based on numerical simulation technology, some influence factors such as different restriction means including the setup of vertical support or fixed connection between pylon and girder, and elastic constraint along longitude of girder, as well as whether setting the auxiliary piers, the location and the number of the auxiliary pier and the changes of the dead load are chosen in order to study in depth the effects on the first-order longitudinal frequency, first-order vertical-bending frequency, first-order transverse-bending frequency and the first-order torsional frequency of self-anchored cable-stayed suspension bridges. The results obtained here have an important guiding significance to optimize structure design and defend risk.

Study on the Joint Part of Self-anchored Cable-stayed Suspension Bridge with Hybrid Girder

This paper has studied on internal force continuity of hybrid girder self-anchored cable-stayed suspension bridge beam joint parts. The beam joint part of hybrid girder self-anchored cable-stayed suspension bridge, with 800m main span, is analyzed with plane 6 nodes finite element. The stress of beam joint parts is gotten. The analysis showed that the stress mutation on the transition section can be alleviated with appropriate construction form.

Geometric Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges

Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

Stochastic Aerostatic StabilityAnalysis of Self-Anchored Cable-Stayed Suspension Bridges

In order to study the influence of complex structure parameters uncertainty on its aerostatic stability, the method of response surface was adopted and random variables that have significant impact on the dependent variables was selected to fit response surface. Based on the above mentioned method, stochastic analysis of aerostatic stability of a self-anchored cable-stayed suspension bridge was analyzed. The result shows that randomness of material and geometrical size have obvious influence to aerostatic instability critical wind of the self-anchored cable-stayed suspension bridges and randomness of the cross area and density of girder are most sensitive to it. The research can provide references for the self-anchored cable-stayed suspension bridge structure analysis and give the corresponding idea for the random parameter uncertainty analysis of complex structures.

Horizontal Seismic Response of Self-Anchored Cable-Stayed Suspension Bridge under Pile-Soil-Structure Interaction

Based on scheme of Dalian gulf cross-sea bridge, in this paper, a 3-dimensional FE model for Self-anchored cable-stayed suspension bridge is established with finite element program and pile-soil-structure interaction is simulated by use of the equivalent embed fixation model. Based on the FE model, model analysis is carried out and the effects of pile-soil-structure interaction on dynamic behavior of long-span self-anchored cable-stayed suspension bridge are specially studied. The seismic response analysis result considering that pile-soil-structure interaction was compared with that of without considering such interaction. The analysis result show that interaction reduced horizontal displacement in middle span of stiffening beam and top of tower, horizontal moment not only at bottom of tower, but also assistant piers. The research results provide some theoretical foundation to composite structure system.

Research of Longitudinal Seismic Response of Self-Anchored Cable-Stayed Suspension Bridge under Pile-Soil-Structure Interaction

Based on scheme of Dalian gulf cross-sea bridge, in this paper, a 3-dimensional FE model for Self-anchored cable-stayed suspension bridge is established with finite element program and pile-soil-structure interaction is simulated by use of the equivalent embed fixation model. Based on the FE model, model analysis is carried out and the effects of pile-soil-structure interaction on dynamic behavior of long-span self-anchored cable-stayed suspension bridge are specially studied. The seismic response analysis result considering that pile-soil-structure interaction was compared with that of without considering such interaction. The analysis result show that interaction extend the nature period of structure, has the greatest impact to the first vibration mode; meanwhile, enlarged longitudinal displacement and moment of stiffening beam in middle of main span, longitudinal displacement on top of tower and axial force at bottom, but reduced the moment of tower at bottom. The research results provide some theoretical foundation to composite structure system.

The Design of Jianshe Bridge

Jianshe bridge is the first self-anchored cable-stayed suspension bridge in the world, localed in Dalian, China. Cable-stayed suspension was presented in history, however cable-stayed bridge and self-anchored suspension combine to make a new type system, which is economy and fit for large span bridge. This paper presents the design of Jianshe bridge. The static and dynamic character of the system and the fatigue of suspender are presented. The computing model of this new system is also introduced in the paper. The structure internal force nonlinearity and stress of the bridge are analyzed. Then analyse the calculate results and draw the conclusions, which self-anchored cable-stayed suspension bridge is fit for large-span bridge, cross suspender can reduce stress amplitude and overcome fatigue problem, and Wind-resistant stability of self-anchored cable-stayed suspension bridge is better than earth anchored system.

Vertical Seismic Response of Self-Anchored Cable-Stayed Suspension Bridge under Pile-Soil-Structure Interaction

Based on scheme of Dalian gulf cross-sea bridge, in this paper, a 3-dimensional FE model for Self-anchored cable-stayed suspension bridge is established with finite element program and pile-soil-structure interaction is simulated by use of the equivalent embed fixation model. Based on the FE model, model analysis is carried out and the effects of pile-soil-structure interaction on dynamic behavior of long-span self-anchored cable-stayed suspension bridge are specially studied. Under vertical excitation, the seismic response analysis result considering that pile-soil-structure interaction was compared with that of without considering such interaction. The analysis result show that interaction reduced longitudinal displacement of stiffening beam in middle of main span and tower at bottom, moment at bottom of tower and auxiliary pier pile, but enlarged the moment of conjoining section between steel and steel beam. The research results provide some theoretical foundation to composite structure system.