scholarly journals Studying Bump at Bridge Approach of Short Subgrade with Oblique Prestressed Concrete Overlaying Asphalt Layer

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Fuqiang Liu ◽  
Mulian Zheng ◽  
Tao Wang ◽  
Shuai Wang ◽  
Linlin Zhu
Keyword(s):  
Layer Thickness ◽  
Prestressed Concrete ◽  
Differential Settlement ◽  
Base Layer ◽  
Additional Stress ◽  
Vertical Acceleration ◽  
Finite Element Software ◽  
Bridge Approach ◽  
Void Area ◽  
Control Criteria

The differential settlement of short subgrade between two highway structures (bridges, tunnels, culverts, etc.) is significantly greater than that of the other subgrade for the insufficient compaction of short subgrade owing to limited construction site. This paper aims to establish the control criteria to prevent bump at bridge approach for differential settlement of short subgrade with oblique prestressed concrete overlying asphalt layer (AC + OPC) composite pavement. In this work, the short subgrade and AC + OPC composite pavement were defined. Meanwhile, the driving comfort was analysed and the control criteria for differential settlement of short subgrade with different lengths were obtained based on the driving comfort using the driving comfort test. Finally, the effects of different layer parameters on stress and deflection were investigated and the control criteria for differential settlement of short subgrade were established based on the void area beneath the slab using the finite element software ANSYS. Results show that the length of short subgrade between two highway structures is defined to be less than 200 m. The vehicle speed and longitudinal slope have significant effects on the vertical acceleration. The asphalt layer modulus, OPC layer thickness and modulus, base layer thickness and modulus, and foundation modulus have effects on the flexural stress and deflection, especially the OPC layer thickness. The relationship between the additional stress and void area beneath the slab is derived. In addition, the control criteria for differential settlement of short subgrade with different lengths are put forward based on the void area beneath the slab and driving comfort. The application of AC + OPC composite pavement can prevent bump at bridge approach of short subgrade effectively. The results of this paper can provide guidance for the application of AC + OPC composite pavement.

scholarly journals Study on Long-Term Performance of Geogrid-Reinforced and Pile-Supported Embankment at Bridge Approach

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jun Zhang ◽  
Ziyang Zhao ◽  
Zhijie Sun
Keyword(s):  
Numerical Model ◽  
Model Tests ◽  
Differential Settlement ◽  
Finite Element Software ◽  
Bridge Approach ◽  
Long Term Performance ◽  
Term Performance ◽  
Grps Embankment ◽  
Pile Supported Embankment

Bridges have been widely used in highway and railway engineering, especially in mountain areas. The differential settlement between bridge abutment and approach embankment is one of the most challenging problems, and it will result in “bumps” to affect the driving safety and comfortableness at the end of a bridge. The geogrid-reinforced and pile-supported embankment (GRPS embankment) is proposed to mitigate the differential settlement at the bridge approach. In this paper, the model tests and numerical studies are carried out to study the long-term performance of the GRPS embankment considering the consolidation of subsoil. Firstly, a series of model tests are conducted to evaluate the long-term performance of the GRPS embankment using a specially designed model box. Then, the numerical model is constructed using the finite element software MIDAS, and the numerical model is verified from the model test results. Finally, a parametric study is conducted to investigate the influences of pile net spacing, pile modulus, and filling modulus.

Elasto-Plastic Analysis of Seismic Response of Valve-Hall Structure with Suspension Valves of Large-Scale Converter Station

2011 ◽  
Vol 94-96 ◽  
pp. 1941-1945
Author(s):  
Yi Wu ◽  
Chun Yang ◽  
Jian Cai ◽  
Jian Ming Pan
Keyword(s):  
Seismic Response ◽  
Large Scale ◽  
Seismic Waves ◽  
Tensile Force ◽  
Response Analysis ◽  
Vertical Acceleration ◽  
Seismic Responses ◽  
Seismic Response Analysis ◽  
Finite Element Software ◽  
Plastic Analysis

Elasto-plastic analysis of seismic responses of valve hall structures were carried out by using finite element software, and the effect of seismic waves on the seismic responses of the valve hall structures and suspension equipments were studied. Results show that significant torsional responses of the structure can be found under longitudinal and 3D earthquake actions. Under 3D earthquake actions, the seismic responses of the suspension valves are much more significant than those under 1D earthquake actions, the maximum tensile force of the suspenders is about twice of that under 1D action. The seismic responses of the suspension valves under vertical earthquake actions are much stronger than those under horizontal earthquake actions, when suffering strong earthquake actions; the maximum vertical acceleration of the suspension valves is about 4 times of that under horizontal earthquake actions. It is recommended that the effects of 3D earthquake actions on the structure should be considered in seismic response analysis of the valve hall structure.

Consideration of Both Extensional and Shear Strain of Core Material in Modal Property Estimation of Sandwich Plates

1995 ◽  
Author(s):  
Byung-Chan Lee ◽  
Kwang-Joon Kim
Keyword(s):  
Shear Strain ◽  
Layer Thickness ◽  
Sandwich Beam ◽  
Base Layer ◽  
Core Material ◽  
Viscoelastic Layer ◽  
Sandwich Plates ◽  
Modal Parameter ◽  
The Core ◽  
Plate Length

Abstract In vibration analysis of sandwich beam/plates, it is often assumed that there occurs shear deformation only, i.e. no extension or compression, in the core viscoelastic layer. Certainly, this assumption may have limitations, for example, with increase of the core thickness or frequency range of vibration. The purpose of this paper is to consider the extentional as well as shear strain of the core for modal parameter estimation of the sandwich plates and to investigate how much error will be caused by neglecting the extension or compression in the core material. Natural frequencies and modal loss factors are estimated for a simply supported square plates under each of the above two assumptions. Nondimensional characteristic equations are formulated and solved for various ratios of the base layer thickness to plate length, core to base layer thickness, and constraining layer to base layer thickness.

scholarly journals Effect of Bridge-Pier Differential Settlement on the Dynamic Response of a High-Speed Railway Train-Track-Bridge System

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaohui Zhang ◽  
Yao Shan ◽  
Xinwen Yang
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Tensile Force ◽  
Differential Settlement ◽  
Bridge Pier ◽  
Vertical Acceleration ◽  
Train Track ◽  
Allowable Limit ◽  
High Speed Railway ◽  
Track Bridge

A model based on the theory of train-track-bridge coupling dynamics is built in the article to investigate how high-speed railway bridge pier differential settlement can affect various railway performance-related criteria. The performance of the model compares favorably with that of a 3D finite element model and train-track-bridge numerical model. The analysis of the study demonstrates that all the dynamic response for a span of 24 m is slightly larger than that for a span of 32 m. The wheel unloading rate increases with pier differential settlement for all of the calculation conditions considered, and its maximum value of 0.695 is well below the allowable limit. Meanwhile, the vertical acceleration increases with pier differential settlement and train speed, respectively, and the values for a pier differential settlement of 10 mm and speed of 350 km/h exceed the maximum allowable limit stipulated in the Chinese standards. On this basis, a speed limit for the exceeding pier differential settlement is determined for comfort consideration. Fasteners that had an initial tensile force due to pier differential settlement experience both compressive and tensile forces as the train passes through and are likely to have a lower service life than those which solely experience compressive forces.

Research on Monitoring Technology of Long-Span Prestressed Concrete Construction

2012 ◽  
Vol 170-173 ◽  
pp. 3145-3152
Author(s):  
Ji Liang Liu ◽  
Ming Jin Chu ◽  
Shu Dong Xu ◽  
Ying Ying Yin
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Simulation Analysis ◽  
Reference Value ◽  
Element Model ◽  
Construction Process ◽  
Finite Element Software ◽  
Prestressed Concrete Beam ◽  
Comprehensive Service

The author performs simulation analysis on construction process of roofing prestressed concrete beam of comprehensive service center in Beijing Institute of Civil Engineering and Architecture by finite element software Midas/Gen, so as to determine the monitoring programme according to the analysis results. The monitoring results indicate that the structure is safe; the theoretical value of simulation analysis is well matched with actual monitoring value, which means that the finite element model of construction process of roofing prestressed concrete beam is correct, the simulation method is feasible and the construction process is reasonable. It has important reference value for construction and monitoring of subsequent similar projects.

Dependence of Hot Electron Transport on Base Layer Thickness of Magnetic Tunnel Transistor

2004 ◽  
Vol 43 (5A) ◽  
pp. 2479-2483 ◽  
Author(s):  
Takakazu Hirose ◽  
Yuji Fujiwara ◽  
Mutsuko Jimbo ◽  
Tadashi Kobayashi ◽  
Shigeru Shiomi ◽  
...  
Keyword(s):  
Electron Transport ◽  
Layer Thickness ◽  
Base Layer ◽  
Hot Electron ◽  
Tunnel Transistor ◽  
Hot Electron Transport

The Modification to the FEM Model of the Prestressed Concrete Beam with the Combination of the Data of Static and Dynamic Test

2014 ◽  
Vol 707 ◽  
pp. 401-405
Author(s):  
Tao He ◽  
Chong Ji Zhao
Keyword(s):  
Prestressed Concrete ◽  
Static Load ◽  
Dynamic Test ◽  
Load Test ◽  
State Variables ◽  
Static Load Test ◽  
Fem Model ◽  
Modified Model ◽  
Finite Element Software ◽  
T Beam

Using the finite element software ANSYS to establish the model of prestressed concrete T beam .With the combination of dynamic and static load test data, the objective function was constructed by taking the vertical deflection of the static load test and the top five vertical natural frequency of dynamic test as state variables. The results revealed that,after being modified ,the error between the calculation value and the testal results of the model was converged in a reasonable error range.In addition ,The modified model could be used in the assessment of bridge structure performance,and it shows the practical application value.

Mechanics Analysis and Construction Method of Prestressed Concrete Pipe

2013 ◽  
Vol 351-352 ◽  
pp. 30-33
Author(s):  
Wei Wu ◽  
Jing Ji
Keyword(s):  
Prestressed Concrete ◽  
Simulation Analysis ◽  
External Pressure ◽  
Construction Process ◽  
Work Process ◽  
Finite Element Software ◽  
Concrete Pipe ◽  
Mechanics Analysis ◽  
Analysis Design ◽  
Design And Construction

Simulation analysis on prestressed concrete pipe was carried out by using finite element software ANSYS. The internal and external pressure which the pipeline is subject to is simulated in real work process, and deformation and stress distribution of building pipeline structure are got. We have great understanding in the mechanical properties, at the same time give a detailed introduction for the prefabrication and on-site construction process. Three aspects in this paper for analysis, design and construction can provide safe and reliable reference for design and construction of similar pipeline structure.

Rail Dynamic Vibration Absorber Design and Vibration Reduction Analysis

2011 ◽  
Vol 42 (11) ◽  
pp. 15-19
Author(s):  
Linya Liu ◽  
Bin Zhang ◽  
Jin Wang
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Vertical Displacement ◽  
Vibration Absorber ◽  
Vertical Acceleration ◽  
Dynamic Vibration Absorber ◽  
Finite Element Software ◽  
Dynamic Vibration ◽  
Damped System

The rail between two adjacent fasteners is regarded as the research object, and the rail is simplified as the main vibration system of undamped single degree of freedom, which supports the elastic components. The dynamic vibration absorber is simplified as a spring and damped system of 3-DOF(three degrees of freedom), to establish a mathematical model of rail dynamic vibration absorber. Through relevant theories, the parameter values of dynamic vibration absorber can be deduced when it achieves the best absorption effect. In accordance with the parameters, the scantlings of the structure of the dynamic vibration absorber can also be designed. Through the finite element software, the finite element model CRTS _ Ballastless Track system is established; with consideration of the value of irregularity, we load it variously. Analysis results showed that: compared to the rail and track where the dynamic vibration absorber is not installed, the maximum vertical displacement of the rail and track where a dynamic vibration absorber is installed was reduced by 65% and 67% respectively, the maximum vertical acceleration decreased by 75% and 70% and around, which reveals that the rail dynamic vibration absorber has a good vibration-reducing effect.

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