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Zhu J.-S.,Tianjin University | Zhu J.-S.,Key Laboratory of Coast Civil Structure Safety | Yi Q.,Tianjin University
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2012

In order to investigate the Non-uniformity of stress impact factor of suspenders on half-through or though arch bridges under dynamic loading of road vehicles, the vehicle-bridge vibration based analysis method was proposed. The vehicle was modeled as a four-degree-of-freedom system and the vibration equations of the vehicle model were deduced based on the D'Alembert principle. Then finite element method was used to discretize the bridge and a finite element model was set up. According to the conditions of displacement and force compatibility between vehicle and bridge, the vibration equations of vehicle and bridge are coupled. A professional procedure VBAP was programmed based on Newmark-β algorithm in MATLAB to analyze the vehicle-bridge system's coupled vibration. Taking a concrete-filled steel tube arch bridge as example, the influences of damping ratio, road roughness, vehicle weight and vehicle speed on stress impact factors of suspenders were analysed using the method and program mentioned in the paper.


Lu H.,Tianjin University | Zhu J.,Key Laboratory of Coast Civil Structure Safety | Xiong C.,Key Laboratory of Coast Civil Structure Safety
IABSE Conference, Guangzhou 2016: Bridges and Structures Sustainability - Seeking Intelligent Solutions - Report | Year: 2016

The vibrational behavior of a damaged beam-like bridge with one or several nonpropagating edge cracks subjected to a moving vehicle is studied in this paper. The effect of the crack depth, the crack location, the moving vehicle mass, the moving vehicle velocity on the beam-like bridge deflection will be analyzed through a numerical example using vehicle-bridge coupled vibration programme established by MATLAB combined with finite element software ANSYS. The model predictions are shown to be accurate for both the undamaged and the damaged cases, and the vibration characteristics of damaged beam structure subjected to a moving vehicle obtained from the simulation can provide evidence for the damage identification and bridge condition assessment.


Bi J.-H.,Tianjin University | Bi J.-H.,Key Laboratory of Coast Civil Structure Safety | Wang J.,Tianjin University | Shao Q.,Siemens AG | Lu P.,Tianjin University
Gongcheng Lixue/Engineering Mechanics | Year: 2014

Rain-wind induced vibration (RWIV) is the phenomenon that a stay cable may vibrate with a large amplitude and a low frequency under the special conditions of wind and rain. According to lubrication theory and vibration theory of a single-mode system, the coupled equations of water film evolution and cable vibration are presented. The wind pressure and friction coefficients in water film evolution equations are obtained by computational fluid dynamics (CFD) software-Fluent. To reveal the mechanism of RWIV, the relationships between the water film morphology, the lift and vibration of a cable are discussed by numerical solving the coupled equations. The results show that cable lift oscillates periodically due to the periodical variation of water film morphology, which causes the large amplitude vibration of a cable. This confirms the conclusion that the main reason for RWIV is the resonance between rivulets and a cable.


Sui C.-E.,Key Laboratory of Coast Civil Structure Safety | Kang J.-F.,Key Laboratory of Coast Civil Structure Safety | Wang X.-Z.,Key Laboratory of Coast Civil Structure Safety | Xu X.-P.,China Academy of Urban Construction
Applied Mechanics and Materials | Year: 2013

Xiaolangdi sediment tunnel is the first waterway engineering used un-bonded circumferential pre-stressed lining in China. Based on data obtained by concrete strain meters over tensioning and operation periods, strain of concrete creep of sediment tunnel lining was analyzed. The results show that concrete creep developed over tensioning period is 26.4% of total strain and 35.8% of elastic strain respectively; Creep strain had a good linear relation with pre-stress and loading time and can be calculated by εc=α Σ σiti, which are agree with the measured results; Over operation period, concrete creep strain can be analyzed by rejecting the effect of temperature and water level from the total strain. © (2013) Trans Tech Publications, Switzerland.


Huang X.,Tianjin University | Huang X.,Key Laboratory of Coast Civil Structure Safety | Li Z.,Tianjin University | Li Z.,Key Laboratory of Coast Civil Structure Safety
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2011

Hydrodynamic pressure on bridge piers would occur during water-pier interaction under earthquakes. The influence of hydrodynamic pressure on the seismic response of bridge piers is studied. Hydrodynamic pressure formula is established using both the Morison equation method and the radiation wave theory. The influence of hydrodynamic pressure on the seismic response of bridge piers is studied and the two methods are compared. The influence of hydrodynamic pressure on the seismic response of a pier with pile foundation is analyzed with consideration of soil-structure interaction and bidirectional earthquake action. The results indicate that the dynamic characteristics of pier changed and the seismic response is augmented because of the hydrodynamic pressure effect, and this effect becomes more significant with the increase of the relative water depth. For piers with wider upstream face, the influence of hydrodynamic pressure from the Morison equation is obviously larger than that from the radiation wave theory. The action of hydrodynamic pressure decreases if the soil-structure interaction is considered, but the influence of hydrodynamic pressure cannot be ignored. The influence of hydrodynamic pressure will be enhanced under bidirectional earthquake action. In conclusion, the influence of hydrodynamic pressure on the seismic response of piers needs to be considered in seismic analysis of large bridge piers in deep water.


Jiang N.,Tianjin University | Jiang N.,Key Laboratory of Coast Civil Structure Safety | Zhao H.,Henan Electrical Power Survey And Design Institute
Applied Mechanics and Materials | Year: 2013

In this paper, the vibration equation of the structure-soil nonlinear interaction system was qualitatively analyzed by using the modern dynamic theory. Based on the multilinear kinematic hardening mode, the nonlinear finite element method was applied for the solution of the horizontal and torsional stiffness between the foundation and soil interaction system. And a mechanical model of the structure-soil nonlinear interaction system was established. The Lagrange energy method is used to build the coupling vibration equation of the structural horizontal displacement and torsion. The Primary resonance of the structure-soil nonlinear interaction system was studied by using the multiple scales method. By analyzing the nonlinear coupling interaction between different structures and soil, the coupling effect of structure system was revealed by appearing energy transfer from high order horizontal vibration to low order torsional vibration, and also the vibration characteristics and the behavior of energy transfer were obtained. © (2013) Trans Tech Publications, Switzerland.


Wang J.,Tianjin Chengjian University | Lu P.,Central Research Institute of Building and Construction CO. | Bi J.-H.,Tianjin University | Bi J.-H.,Key Laboratory of Coast Civil Structure Safety | And 2 more authors.
Zhendong Gongcheng Xuebao/Journal of Vibration Engineering | Year: 2016

Considering the effects of along-wind vibration of cable, 2-DOF model of rain-wind induced vibration (RWIV) of stay cable is presented based on lubrication theory in this paper. Wind pressure and friction coefficients in water film evolution equation are obtained by computational fluid dynamics (CFD) software-Fluent. The characteristics of water film evolution (movements of rivulets), aerodynamic lift and drag, across-wind and along-wind vibrations of cable are respectively investigated by numerical solving the coupled equations of water film evolution and cable vibrations. On this basis, the mechanism of RWIV is revealed by discussing their relationships as follows: cable lift and drag oscillate periodically due to the periodical oscilations of rivulets in circumferential direction, which cause the large amplitude vibrations of cable in across-wind and along-wind directions; and conversely, the periodical vibrations of cable strengthen the periodicity of rivulets' oscilations. So the resonance between rivulets and cable causes RWIV. © 2016, Nanjing Univ. of Aeronautics an Astronautics. All right reserved.


Ren W.-D.,China Railway Real Estate Group Tianjin Co. | Zhang T.-X.,China Railway Real Estate Group Tianjin Co. | Zhang D.-M.,China Railway Real Estate Group Tianjin Co. | Li Y.-L.,China Railway Real Estate Group Tianjin Co. | And 3 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2013

The multi-level retaining methods such as two-level single-row retaining piles or two-level single-row retaining piles and gravity retaining wall are applied in some large area deep foundation excavation projects. By using the finite element method, the failure modes and stability of multi-level retaining structure composed of one level of double-row piles and the other level of single-row are studied. Parametric study is performed to further analyze the effects of the length of single-row piles, distance between the two-level retaining piles and depth of the two levels on the stability of multi-level retaining structure. The results show that the length of single-row retaining pile can produce significant effect on the overturning stability when the length is longer than a certain length. Only when the distance of the two-level retaining piles is small compared to the excavation depth, it can have a remarkable effect on the overturning stability. The effect of ratio of the depth of the two-level retaining piles on the overturning stability is related to their horizontal distance.


Liu J.,Tianjin University | Liu J.,Key Laboratory of Coast Civil Structure Safety | Zhou D.,Tianjin University
Applied Mechanics and Materials | Year: 2012

In this paper, which was based on a deep excavation project in Tianjin, the factors and laws of surrounding buildings and surface subsidence during the excavation were discussed through the real-time monitoring and comprehensive analysis of the subsidence of structures, underground pipelines, ground surface and some other items. The results show that the main influence scope of the excavation to surrounding areas is about 2 times the depth of the pit, and enhancing the stiffness of surrounding buildings can increase the resistant capacity against deformation, which will provide a reference for the allied projects. © (2012) Trans Tech Publications, Switzerland.


Lu Y.,Tianjin University | Xu L.-H.,Beijing Jiaotong University | Li Z.-X.,Tianjin University | Li Z.-X.,Key Laboratory of Coast Civil Structure Safety | And 2 more authors.
Gongcheng Lixue/Engineering Mechanics | Year: 2011

An energy threshold based damage criterion is proposed to evaluate the axial residual strength of RC columns. The damage criterion is a linear combination of one-step energy threshold and the total hysteretic energy, which can also reflect the coupling effect of them. The shaking table test data, pseudo-static test data and a numerical example are analyzed, and results indicated that the proposed damage criterion can evaluate the residual strength of the RC columns on almost all kinds of conditions, which can be used to analyze the failure path of buildings and bridge structures under seismic excitations.

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