Time filter

Source Type

Dan D.,Tongji University | Chen Y.,Henan Provincial Communications Planning Survey and Design Institute Co. | Xu B.,Tongji University
Shock and Vibration | Year: 2015

The precise measurement of the cable force is very important for monitoring and evaluating the operation status of cable structures such as cable-stayed bridges. The cable system should be installed with lateral dampers to reduce the vibration, which affects the precise measurement of the cable force and other cable parameters. This paper suggests a cable model updating calculation scheme driven by the particle swarm optimization (PSO) algorithm. By establishing a finite element model considering the static geometric nonlinearity and stress-stiffening effect firstly, an automatically finite element method model updating powered by PSO algorithm is proposed, with the aims to identify the cable force and relevant parameters of cable-damper system precisely. Both numerical case studies and full-scale cable tests indicated that, after two rounds of updating process, the algorithm can accurately identify the cable force, moment of inertia, and damping coefficient of the cable-damper system. © 2015 Danhui Dan et al. Source

Chen L.,Hubei Engineering University | Liu Q.,Hubei Engineering University | Zhang G.,CAS Wuhan Institute of Rock and Soil Mechanics | Zhang X.,Henan Provincial Communications Planning Survey and Design Institute Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2014

Inrush accidents generally happen in soluble rock tunnels during underground constructions. However, the number of inrush disasters reported in non-soluble rock tunnels have been increasing recently. They can lead to serious disasters and huge economic losses in tunnel construction. Cases studies were thus carried out and the analysis of three inrush accidents revealed that the causes of the inrush in non-soluble rock tunnels were due to the effects of excavation and blasting disturbance leading to the water and fragmental materials occurred in the fractured and weak zones flowing into the tunnels under their own pressures. The risks carrying environment must have the required physical, spatial and triggering conditions simultaneously: the physical conditions refers to the existence of abundant water and in-situ or exogenous fragments including gravel, sand and mud, etc.; the spatial condition refers to the fracture zone and the weak zone storing and transferring the inrushing materials; The triggering condition is the disturbance to the rock caused by excavation and blasting during the tunnel construction. The predication of inrush disaster in the construction of non-soluble rock tunnels is therefore to identify the fracture and weak zones containing the potential inrushing materials and the components and cementation level of material in two zones a head of the front face of tunneling. A comprehensive geological and geophysical detection and drilling scheme was then carried out to according to the material and spatial conditions in inrush disaster; The characteristics of seismic dynamic response of the parameters such as the reflection amplitude ratio and the wave axis similarity to anomaly geological objects in tunnel geologic prediction(TGP) were constructed. The approach was applied to the fault fracture zone F17 in anterior tunnels. The macro engineering geological analysis, geological investigation and experiments in excavated sections and the trends tracking were performed to reveal the statistical and mechanical characteristics of the surrounding rocks. The long range TGP and the short range ground penetration radar detections and the horizontal drilling were performed to identify the risks containing environment of inrushing disaster in the section unexcavated. The precise locating of the position, the scale and the spatial distribution of the fault fracture zone were thus be achieved. The material components within the zones and the cementation level were detected and the occurrences of inrush accidents were predicted successfully. Source

Li F.,Henan Provincial Communications Planning Survey and Design Institute Co.
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2012

According to the characteristics of self-anchored cable-supported bridges, a new-style steel-concrete joint was proposed. Based on one sea-crossing bridge, a space finite element model that contains solid elements and shell elements was built by ANSYS. Meanwhile, the bond-slip behavior of steel and concrete is also taken into account. By the stress level analysis of several different contact surfaces, the force transfer principle and stress distribution characteristics of the steel-concrete joint of self-anchored cable-supported bridges were studied, which will help to design the steel-concrete joint of self-anchored cable-supported bridges. Source

Dan D.,Tongji University | Chen Y.,Henan Provincial Communications Planning Survey and Design Institute Co. | Xiao R.,Tongji University
Earthquake Engineering and Engineering Vibration | Year: 2014

A numerical solution based on the Steffensen stable point iterative method is proposed to resolve the transcendental frequency equation of a stay cable-damper system. The frequency equation, which considers clamped supports and flexural rigidity of the cable, is intended to investigate the influence of the parameters of the cable damper system on its dynamic characteristics. Two factors involved in the design and construction phases, the damping coefficient induced by external dampers and the cable tension, are the focus of this study. Their impact on modal frequencies and damping ratios in these two phases of cable-damper systems are investigated by resolving the equation with the proposed solution. It is shown that the damping coefficient and cable tension exert more noticeable effects on the modal damping ratios than on the modal frequencies of stay cable-damper systems, and the two factors can serve as design variables in the design phase and as adjustment factors in the construction phase. On the basis of the results, a roadmap for system-level optimal design of stay cable-damper systems that can achieve global optimal vibration suppression for the entire bridge is proposed and discussed. © 2014 Institute of Engineering Mechanics, China Earthquake Administration and Springer-Verlag Berlin Heidelberg. Source

Dan D.-H.,Tongji University | Chen Y.-Y.,Henan Provincial Communications Planning Survey and Design Institute Co.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2013

The installation of damper on long cables will change the dynamic characteristics of the cable, and impact on the accuracy of the measurement of cable tension via vibration method. The relative error expressions for cable force identification methods were presented, namely the expressions for numerical model for cable-damper system with double clamped ends, the taut string model with double pinned ends the taut cable (beam) with double pinned ends and the numerical model for taut cable with double clamped ends. By numerical simulations, the impact of parameters of cable and dampers on cable force identification methods were investigated. The relative error scope of these methods were compared and analysed. The best choise of the cable force identification method was proposed to be that based on the numerical solution of frequency transcendental equation of cable damper system. Source

Discover hidden collaborations