scholarly journals Appropriate Matching Locations of Rail Expansion Regulator and Fixed Bearing of Continuous Beam Considering the Temperature Change of Bridge

2020 ◽  
Vol 10 (17) ◽  
pp. 6046
Author(s):  
Ping Lou ◽  
Te Li ◽  
Xinde Huang ◽  
Ganggui Huang ◽  
Bin Yan
Keyword(s):  
Temperature Change ◽  
Element Model ◽  
Continuous Beam ◽  
Fixed Bearing ◽  
Effective Measure ◽  
Long Span ◽  
Continuous Beams ◽  
Additional Force ◽  
Continuously Welded Rail ◽  
Nonlinear Finite Element Model

Due to the temperature change of bridges, there is a great additional force in continuously welded rails on continuous bridges. Laying rail expansion regulators is an effective measure to reduce the additional force. The nonlinear finite element model is presented for a continuously welded rail track with a rail expansion regulator resting on the embankment and simple and continuous beams, considering the temperature change of the bridge. Then, a method is proposed to determine the locations of the rail expansion regulator and the fixed bearing of the continuous beam, corresponding to the maximum additional forces of rail reaching minimum values. Their appropriate matching locations are recommended based on the obtained influence laws of any locations of the rail expansion regulator and the fixed bearing of the continuous beam on the maximum additional forces of rail. The results can provide the theoretical basis for the design of the rail expansion regulator and the fixed bearing of long-span continuous bridges.

scholarly journals Seismic Response Mitigation of a Long-Span Tower Bridge with Two Types of Constraint System

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Li Xu ◽  
Qingfei Gao ◽  
Junhao Zheng ◽  
Chuanhui Ding ◽  
Kang Liu
Keyword(s):  
Element Model ◽  
Main Beam ◽  
Seismic Load ◽  
Viscous Damper ◽  
Viscous Dampers ◽  
Damping Effect ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Drift Frequency ◽  
Nonlinear Finite Element Model

The stress of the main tower of a cable-stayed bridge depends on the connection type between the tower and deck. In order to study the most suitable longitudinal damping mode for a long-span cable-stayed bridge. In this article, a nonlinear finite element model is established based on a large span concrete cable-stayed bridge with a main span of 680 m. Without considering the influence of the transverse constraint, the damping effect of the elastic connection device and the viscous damper is simulated when the longitudinal seismic load is input. The results show that the stiffness of the main beam is increased by installing the elastic connection device, so the longitudinal drift frequency of the main beam is increased, but the stiffness of the structure is not changed by installing the viscous damper. Both viscous dampers and elastic connection structures can reduce the longitudinal displacement of the beam end, but viscous dampers are more favorable for the stress of the main tower. In terms of damping effect, viscous dampers are more suitable for long-span cable-stayed bridges, but, in terms of economy and parameter control, elastic connection devices have more advantages.

Time history analysis-based nonlinear finite element model updating for a long-span cable-stayed bridge

2020 ◽  
pp. 147592172096386
Author(s):  
Kaiqi Lin ◽  
You-Lin Xu ◽  
Xinzheng Lu ◽  
Zhongguo Guan ◽  
Jianzhong Li
Keyword(s):  
Finite Element ◽  
Response Time ◽  
Finite Element Model ◽  
Model Updating ◽  
Time History ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Long Span ◽  
Time Histories ◽  
Nonlinear Finite Element Model

Accurate finite element models play significant roles in the design, health monitoring and life-cycle maintenance of long-span bridges. However, due to uncertainties involved in finite element modelling, updating of the finite element model to best represent the real bridge is inevitable. This is particularly true after a long-span bridge experiences a moderate or severe earthquake and suffers some damage. This study thus proposes a time history analysis-based nonlinear finite element model updating method for long-span cable-stayed bridges. Special efforts are made to (1) establish the response time history-based objective functions and associated acceptance criteria, (2) conduct comprehensive sensitivity analyses to select appropriate nonlinear updating parameters and (3) develop a highly efficient cluster computing-aided optimization algorithm. A scaled structure of the Sutong cable-stayed bridge in China is adopted as a case study. Three nonlinear test cases performed in the shake table tests of the scaled bridge are used to validate the feasibility and accuracy of the proposed method. A good agreement is observed between the simulated response time histories and the measured response time histories for the scaled bridge under both moderate and strong ground motions. The proposed method could provide an accurate nonlinear finite element model for better performance assessment, damage detection and life-cycle maintenance of long-span cable-stayed bridges.

The Applications of Laminated Rubber Bearing on the Seismic Control of the Continuous Beam

2014 ◽  
Vol 644-650 ◽  
pp. 5046-5049
Author(s):  
Hang Sun ◽  
Xiu Yun Gao ◽  
Ji Wu Ding
Keyword(s):  
Element Model ◽  
Continuous Beam ◽  
Seismic Excitations ◽  
Seismic Control ◽  
Near Fault ◽  
Long Period ◽  
Continuous Beams ◽  
Rubber Bearing ◽  
Laminated Rubber Bearing ◽  
Seismic Forces

Aiming at the phenomenon that the fixed piers of the continuous beams have been damaged during the earthquakes, In this paper the seismic responses are carried on based on a four-span continuous beam, pot rubber bearing and laminated rubber bearing are selected, and corresponding finite element model is built. The results indicate that the distributions of the longitude seismic forces between the piers are more reasonable for the latter bearing, especially under the long period and near-fault seismic excitations. The possiblity of adopting the laminated rubber bearing on the seismic control on the continuous beam are discussed, and the results can be referrd by the same bridges during designing.

scholarly journals Research on the longitudinal mechanical behaviours of subway turnouts of large slope under train braking force

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110283
Author(s):  
Zhiping Zeng ◽  
Ji Hu ◽  
Chunyu Tian ◽  
Ping Li ◽  
Xiangdong Huang ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Change ◽  
Mechanical Characteristics ◽  
Element Model ◽  
Longitudinal Displacement ◽  
Longitudinal Deformation ◽  
Longitudinal Stiffness ◽  
Mechanical Behaviours ◽  
Longitudinal Resistance ◽  
Safety And Stability

To study subway turnouts’ adaptability to steep gradients, a finite element model of a metro No. 9 simple turnout was established. The main works include: (1) The train’s most unfavourable loading condition was modelled. (2) The turnout’s longitudinal displacement and stress were analysed with different gradients under the train braking load, temperature change load and a combination of the two, to determine the structure’s safety and stability under the most unfavourable working conditions. (3) The turnout structure’s cumulative longitudinal deformation under reciprocating load was studied. Both a fastener longitudinal resistance-displacement experiment under reciprocating load and a numerical simulation of No. 9 turnout modelled by the finite element modelling software, ANSYS, were carried out to study the gradient’s influence on the turnout’s longitudinal mechanical characteristics. (1) The turnout’s longitudinal displacement and stress increase linearly with an increase in gradient and temperature change, both of which are unfavourable to the turnout structure. As the gradient increases from 0‰ to 30‰, the longitudinal stress and displacement increase by more than 10%. (2) The turnout’s rail strength and displacement on a 30‰ slope under the most unfavourable load conditions are within the specification limitations. (3) Under reciprocating load, the fastener longitudinal stiffness decreases and the maximum and residual longitudinal displacement of the switch rail increase; an increased gradient intensifies these effects on the turnout.

System Level Bench Test for Trailing Arm Strength Estimation

2006 ◽  
Author(s):  
Jaychandar Muthu ◽  
Kanak Soundrapandian ◽  
Jyoti Mukherjee
Keyword(s):  
Failure Mode ◽  
Real Life ◽  
Element Model ◽  
Suspension System ◽  
System Level ◽  
Bench Test ◽  
Component Level ◽  
Arm Strength ◽  
Bench Testing ◽  
Nonlinear Finite Element Model

For suspension components, bench testing for strength is mostly accomplished at component level. However, replicating loading and boundary conditions at the component level in order to simulate the suspension system environment may be difficult. Because of this, the component's bench test failure mode may not be similar to its real life failure mode in vehicle environment. A suspension system level bench test eliminates most of the discrepancies between simulated component level and real life vehicle level environments resulting in higher quality bench tests yielding realistic test results. Here, a suspension level bench test to estimate the strength of its trailing arm link is presented. A suspension system level nonlinear finite element model was built and analyzed using ABAQUS software. The strength loading was applied at the wheel end. The analysis results along with the hardware test correlations are presented. The reasons why a system level test is superior to a component level one are also highlighted.

Integrity Assessment of Damaged Flexible Pipe Cross-Sections

2014 ◽  
Author(s):  
Guomin Ji ◽  
Bernt J. Leira ◽  
Svein Sævik ◽  
Frank Klæbo ◽  
Gunnar Axelsson ◽  
...  
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Computer Code ◽  
Flexible Pipe ◽  
Dynamic Stresses ◽  
Integrity Assessment ◽  
Residual Capacity ◽  
Nonlinear Finite Element Model

This paper presents results from a case study performed to evaluate the residual capacity of a 6″ flexible pipe when exposed to corrosion damages in the tensile armour. A three-dimensional nonlinear finite element model was developed using the computer code MARC to evaluate the increase in mean and dynamic stresses for a given number of damaged inner tensile armor wires. The study also includes the effect of these damages with respect to the associated stresses in the pressure spiral. Furthermore, the implications of a sequence of wire failures with respect to the accumulated time until cross-section failure in a probabilistic sense are addressed.

scholarly journals Application of Laplace Transform to the Free Vibration of Continuous Beams

2017 ◽  
Vol 63 (1) ◽  
pp. 163-180 ◽  
Author(s):  
H.B. Wen ◽  
T. Zeng ◽  
G.Z. Hu
Keyword(s):  
Free Vibration ◽  
Laplace Transform ◽  
Reaction Force ◽  
Bending Moment ◽  
Frequency Equation ◽  
Simplified Model ◽  
Continuous Beam ◽  
Transform Method ◽  
Continuous Beams ◽  
Vibration Problems

AbstractLaplace Transform is often used in solving the free vibration problems of structural beams. In existing research, there are two types of simplified models of continuous beam placement. The first is to regard the continuous beam as a single-span beam, the middle bearing of which is replaced by the bearing reaction force; the second is to divide the continuous beam into several simply supported beams, with the bending moment of the continuous beam at the middle bearing considered as the external force. Research shows that the second simplified model is incorrect, and the frequency equation derived from the first simplified model contains multiple expressions which might not be equivalent to each other. This paper specifies the application method of Laplace Transform in solving the free vibration problems of continuous beams, having great significance in the proper use of the transform method.

Dynamic Characteristics of a Long-Span Cable-Stayed Bridge

2011 ◽  
Vol 480-481 ◽  
pp. 1496-1501
Author(s):  
Liu Hui
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Iteration Method ◽  
Natural Frequencies ◽  
Element Model ◽  
Vibration Modes ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Subspace Iteration ◽  
Floating System

In order to study the dynamic characteristics of a super-long-span cable-stayed bridge which is semi-floating system, the spatial finite element model of this cable-stayed bridge was established in ANSYS based on the finite element theory.Modal solution was conducted using subspace iteration method, and natural frequencies and vibration modes were obtained.The dynamic characteristics of this super-long-span cable-stayed bridge were then analyzed.Results showed that the super-long-span cable-stayed bridge of semi-floating system has long basic cycle, low natural frequencies, dense modes and intercoupling vibration modes.

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