Dynamic response analysis for submerged floating tunnel due to fluid-vehicle-tunnel interaction

Spatial dynamic response of submerged floating tunnel under impact load

Owners of bridges all over the world are facing the task of maintaining them within limited resources. The allocation of resources among the competing deteriorating bridges is a difficult task. Bridge health indices are used for deciding the priority of bridges for maintenance, and for the allocation of resources. Ascertaining the relative importance of bridge components is a prime requirement in the development of the indices. Based on the available literature and preliminary discussions with experts in this field, the bridge components were grouped into seven categories and a questionnaire was developed. The responses to the questionnaire were used in the analytical hierarchy process for deciding the weights (relative importance) of each bridge component. Consequently, based on the literature review, different condition states were defined, and a quantification of different distress types, corresponding to each of the condition states, was made. The weights and condition states of different bridge compo...

Determination of bridge health index using analytical hierarchy process

Experimental study on grouped stud shear connectors in precast steel- UHPC composite bridge

Submerged floating tunnels (SFTs) are innovative structural solutions to waterway crossings, such as sea-straits, fjords and lakes. As the width and depth of straits increase, the conventional structures such as cable-supported bridges, underground tunnels or immersed tunnels become uneconomical alternatives. For the realization of SFT, the structural response under extreme environmental conditions needs to be evaluated properly. This study evaluates the displacements and internal forces of SFT under hydrodynamic and three-dimensional seismic excitations to check the global performance of an SFT in order to conclude on the optimum design. The formulations incorporate modeling of ocean waves, currents and mooring cables. The SFT responses were evaluated using three different mooring cable arrangements to determine the stability of the mooring configuration, and the most promising configuration was then used for further investigations. A comparison of static, hydrodynamic and seismic response envelope curves of the SFT is provided to determine the dominant structural response. The study produces useful conclusions regarding the structural behavior of the SFT using a three-dimensional numerical model.

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Performance Evaluation of Submerged Floating Tunnel Subjected to Hydrodynamic and Seismic Excitations

This paper describes an investigation of vortex-induced vibrations in a submerged floating tunnel (SFT) system. A theoretical model for coupled tube-cable vibration was developed to evaluate the SFT structural dynamic response to water current. The differential equations of the cable and tube coupled motion were derived using the Hamilton principle, and approximate numerical analyses were carried out to determine the coupling effect between cable transverse vibrations and tube vertical vibrations. The results showed that the maximum amplitudes of the cables were greater than the initial disturbance when self-induced resonance occurred. Self-induced resonance can be caused by the vortex-induced vibration of the cables when the flow velocity reaches a certain value. The change in the tube-specific gravity ratio had little effect on the maximum vibration amplitudes of the tube and cables. The vibrations of the tube and cables were more sensitive to changes in the lift coefficient than to the added ma...

Vortex-Induced Dynamic Response Analysis for the Submerged Floating Tunnel System under the Effect of Currents

Experimental and numerical analysis of grouped stud shear connectors embedded in HFRC

A condition assessment model for cable-stayed bridge was proposed, and a cable tension, elevation and frequency condition assessment model was then applied. With the optimized cable tensions as criterion, upper and lower bounds were then introduced. With the elevation of bridge completion as benchmark, and with the allowable vertical displacement of control points to interpolate to generate the upper and lower bounds of elevation, algorithm of condition assessment was programmed. Using moderate index model to interpolate linearly, and with the application of variable weight synthesizing principle (VWSP) and correlation of slope coefficient, according to a set of inspection and monitoring data, performance condition of cable tension, elevation and frequency were calculated. Results showed that with the decrease of balanced coefficient α, the assessment result is a process of degradation. The more divergent the variable weight is, the more severe is the degradation of the bridge component, and the larger is the curvature of curve α-V. Eventually, the model predicted that, for those bridge components whose grade of single survey point is exactly the same, the curvature of curve α-V is constant zero, i.e. there is no correlation between the assessment result and the balanced coefficient α. Numerical simulation showed that it agrees quite well with the expectation.

Condition assessment of long span cable-stayed bridge

Based on variable weight synthesis principle,a cable tension and linetype state assessment model of cable-stayed bridge was established.With the optimized restraint value of cable tension as criterion,upper and lower limit was then proposed.Algorithm of state assessment was programmed,using moderate index model to interpolate linearly,and with the application of variable weight synthesis principle and correlation of slope coefficient,according to a set of measured data,state of cable tensions and linetype were calculated.Calculation results show that with the decrease of balanced coefficient,the assessment result is a process of degradation.The more divergent variable weight is,the more severe the degradation of the bridge component assessment and the largger the curvature of curve will be.It is predicted that,for those bridge component that grade of single survey point is exactly the same,the curvature of curve is constant zero,i.e.,there is no correlation between the assessment result and the balanced coefficient.Numerical simulation results show that it agrees quite well with the expectation.

Assessment the Cable Tension and the Linetype State of Cable-Stayed Bridge Based on Variable Weight Synthesis

According to “General code for design of highway bridges and culverts” (JTG D60-2004), “Wind-resistent design specification for highway bridges” (JTG/T D60-01-2004) and “Load code for the design of building structures” (GB 50009-2001), the transverse direction wind load of long span girder bridge with high pier is calculated. Comparison of the wind load results obtained by different codes is completed under the situation of different terrain, pier height and girder length of bridge. The results show the difference of the wind load given by the three different codes exists. The wind load results predicated by “General code for design of highway bridges and culverts” is the largest compare with the results gained by other two methods. The results predicated by “Wind-resistent design specification for highway bridges” is less than results predicated by General code. While, the results predicated by “Load code for the design of building structures” is the smallest. The wind load calculated according to “Load code for the design of building structures” mainly depends on the experience parameters of architectural construction with larger dimensions, which has a poor applicability to the bridge structure. The effect of fluctuating wind's inertia force of long span girder bridges with high pier can’t be neglected. The wind load results calculated by codes are generally smaller, it is better to determine the wind load internal force through a detailed buffeting analysis.

Xiang Yi-qiang

Papers

Vortex-Induced Dynamic Response Analysis for the Submerged Floating Tunnel System under the Effect of Currents

Experimental and numerical analysis of grouped stud shear connectors embedded in HFRC

Condition assessment of long span cable-stayed bridge

Assessment the Cable Tension and the Linetype State of Cable-Stayed Bridge Based on Variable Weight Synthesis

Analysis and Comparison on Wind Load of Long Span Girder Bridges with High Pier