scholarly journals Accounting for the effect of creep and shrinkage on the stress state of concrete structures of cable-stayed bridges in Myanmar

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Sherali Valiev ◽  
Maung Maung Win Aung ◽  
Ivan Shatilov
Keyword(s):  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Element Analysis ◽  
Box Girder ◽  
Cable Stayed Bridge ◽  
Shrinkage And Creep ◽  
Cable Forces ◽  
Creep And Shrinkage ◽  
Cable Stayed Bridges

The article considers the finite element analysis of the influence of time-dependent processes (creep and shrinkage) of concrete on the structures of a concrete cable-stayed bridge according to Russian, European and American standards. For numerical calculation, the Midas/Civil software was used, which allowed us to take into account elastic short-term deformation and creep deformation, as well as changes in the strength of concrete over time. Long-term deformations in concrete elements could be 1.5~3.0 times higher than elastic deformations and were observed in the first few months, and most of them occurred within five years. The object of research was a cable-stayed bridge with a reinforced concrete beam with a box girder. Three calculation models were used to model concrete shrinkage and creep: according to Russian, European and American standards. The results of the study showed significant discrepancies between foreign and Russian standards for accounting for long-term processes in concrete structures of cable-stayed bridges. Creep and shrinkage processes led to increased displacements in the box girder and pylon. Moreover, with an increase in the humidity of the environment, the deflection of the girder decreased, and the displacement of the pylon slightly increased. The cable-forced was reduced by the shrinkage and creep of the concrete. It was found that the loss of cable forces decreased with increasing humidity of the environment.

A prediction method for cable forces of cable-stayed bridges using fuzzy processing and Bayes estimation

2021 ◽  
Author(s):  
Li Dong ◽  
Bin Xie ◽  
Dongli Sun ◽  
Yizhuo Zhang
Keyword(s):  
Prediction Method ◽  
Practical Method ◽  
Bayes Estimation ◽  
Primary Data ◽  
Force Estimation ◽  
Element Analysis ◽  
Cable Stayed Bridge ◽  
Input Parameters ◽  
Cable Forces ◽  
Cable Stayed Bridges

<p>Cable forces are primary factors influencing the design of a cable-stayed bridge. A fast and practical method for cable force estimation is proposed in this paper. For this purpose, five input parameters representing the main characteristics of a cable-stayed bridge and two output parameters representing the cable forces in two key construction stages are defined. Twenty different representative cable-stayed bridges are selected for further prediction. The cable forces are carefully optimized through finite element analysis. Then, discrete and fuzzy processing is applied in data processing to improve their reliability and practicality. Finally, based on the input parameters of a target bridge, the maximum possible output parameters are calculated by Bayes estimation based on the processed data. The calculation results show that the average prediction error of this method is less than 1% for the twenty bridges themselves, which provide the primary data and less than 3% for an under-construction bridge.</p>

scholarly journals Analysis of Non-Uniform Shrinkage Effect in Box Girder Sections for Long-Span Continuous Rigid Frame Bridge

2018 ◽  
Vol 13 (2) ◽  
pp. 146-155 ◽  
Author(s):  
Zhuoya Yuan ◽  
Pui-Lam Ng ◽  
Darius Bačinskas ◽  
Jinsheng Du
Keyword(s):  
Finite Element ◽  
General Purpose ◽  
Element Analysis ◽  
Box Girder ◽  
Finite Element Program ◽  
Continuous Rigid Frame Bridge ◽  
Rigid Frame ◽  
Shrinkage Effect ◽  
Rigid Frame Bridge

To consider the effect of non-uniform shrinkage of box girder sections on the long-term deformations of continuous rigid frame bridges, and to improve the prediction accuracy of analysis in the design phase, this paper proposes a new simulation technique for use with general-purpose finite element program. The non-uniform shrinkage effect of the box girder is transformed to an equivalent temperature gradient and then applied as external load onto the beam elements in the finite element analysis. Comparative analysis of the difference in deflections between uniform shrinkage and nonuniform shrinkage of the main girder was made for a vehicular bridge in reality using the proposed technique. The results indicate that the maximum deflection of box girder under the action of non-uniform shrinkage is much greater than that under the action of uniform shrinkage. The maximum downward deflection of the bridge girder caused by uniform shrinkage is 5.6 mm at 20 years after completion of bridge deck construction, whereas the maximum downward deflection caused by non-uniform shrinkage is 21.6 mm, which is 3.8 times larger. This study shows that the non-uniform shrinkage effect of the girder sections has a significant impact on the long-term deflection of continuous rigid frame bridge, and it can be accurately simulated by the proposed transformation technique.

Finite Element Analysis on Incremental Launching Construction for Steel Box Girder

2013 ◽  
Vol 671-674 ◽  
pp. 974-979
Author(s):  
Jie Dai ◽  
Jin Di ◽  
Feng Jiang Qin ◽  
Min Zhao ◽  
Wen Ru Lu
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Internal Force ◽  
Element Analysis ◽  
Box Girder ◽  
Finite Element Software ◽  
Cable Stayed Bridge ◽  
Steel Box Girder ◽  
Maximum Value ◽  
Negative Bending

For steel box girder of cable-stayed bridge, which using incremental launching method, during the launching process, structural system and boundary conditions were changing, structure mechanical behaviors were complex. It was necessary to conduct a comprehensive analysis on internal force and deformation of the whole structure during the launching process. Took a cable-stayed bridge with single tower, double cable planes and steel box girder in China as an example; finite element software MIDAS Civil 2010 was used to establish a model for steel box girder, simulation analysis of the entire incremental launching process was carried out. Variation rules and envelopes of the internal force, stress, deformation and support reaction were obtained. The result showed that: the maximum value of positive bending moment after launching complete was 60% of the maximum value of positive bending moment during the launching process. The maximum value of negative bending moment after launching complete was 78% of the maximum value of negative bending moment during the launching process.

scholarly journals Static Experiment and Finite Element Analysis of a Multitower Cable-Stayed Bridge with a New Stiffening System

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaowei Wang ◽  
Yingmin Li ◽  
Weiju Song ◽  
Jun Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Force ◽  
Element Analysis ◽  
Cable Stayed Bridge ◽  
Practical Engineering ◽  
Static Experiment ◽  
Stiffening Effect ◽  
Better Than ◽  
Cable Stayed Bridges

Based on the stiffness limitations of the midtower in multitower cable-stayed bridges, a new stiffening system (tie-down cables) is proposed in this paper. The sag effects and wind-induced responses can be reduced with the proposed system because tie-down cables are short and aesthetic compared with traditional stiffening cables. The results show that the stiffening effect of tie-down cables is better than that of traditional stiffening cables in controlling the displacement and internal force of the bridge based on a static experiment and finite element analysis. Therefore, the proposed system can greatly improve the overall stiffness of a bridge, and its stiffening effect is better than that of traditional stiffening cables in controlling the displacement and internal force. The results provide a reference for the application of such systems in practical engineering.

Monitored structural behavior of a long span cable-stayed bridge under environmental effects

2018 ◽  
Vol 4 (4) ◽  
pp. 137 ◽  
Author(s):  
Alemdar Bayraktar ◽  
Ashraf Ashour ◽  
Halil Karadeniz ◽  
Altok Kurşun ◽  
Arif Erdiş
Keyword(s):  
Air Temperature ◽  
Environmental Effects ◽  
Monitoring Data ◽  
Structural Behavior ◽  
Steel Cable ◽  
Daily Monitoring ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Cable Forces ◽  
Cable Stayed Bridges

An accurate numerical analysis of the behavior of long-span cable-stayed bridges under environmental effects is a challenge because of complex, uncertain and varying environmental meteorology. This study aims to investigate in-situ experimental structural behavior of long-span steel cable-stayed bridges under environmental effects such as air temperature and wind using the monitoring data. Nissibi cable-stayed bridge with total length of 610m constructed in the city of Adıyaman, Turkey, in 2015 is chosen for this purpose. Structural behaviors of the main structural elements including deck, towers (pylons) and cables of the selected long span cable-stayed bridge under environmental effects such as air temperature and wind are investigated by using daily monitoring data. The daily variations of cable forces, cable accelerations, pylon accelerations and deck accelerations with air temperature and wind speed are compared using the hottest summer (July 31, 2015) and the coldest winter (January 1, 2016) days data.

Simulation Analysis of Shrinkage and Creep for Bowstring Arch Bridge Steel Tube Concrete in Different Specification

2012 ◽  
Vol 178-181 ◽  
pp. 2219-2223 ◽  
Author(s):  
Rong Ling Zhang ◽  
Liang Wang ◽  
Chang An Yang ◽  
Bing Yang ◽  
Chang Yue Zhu ◽  
...  
Keyword(s):  
Simulation Analysis ◽  
Steel Tube ◽  
Analysis Method ◽  
Accurate Calculation ◽  
Element Analysis ◽  
Concrete Shrinkage ◽  
Shrinkage And Creep ◽  
Bridge Steel ◽  
Influence Degree ◽  
Creep And Shrinkage

The actual bowstring arch CFST is taken as the background,the paper using finite element analysis method, researched the shrinkage and creep of combination of steel and concrete structure. Through the use of different countries regulation of shrinkage and creep of concrete, the effects of the structure deflection separately were studied ,then explain the different influence degree of different norms in the calculation of the creep and shrinkage of concrete; The paper also has also put forward the doubt about accurate calculation concrete filled steel tubular structure shrinkage and creep of concrete, it puts forward new requirements for the research and standards about steel tube concrete shrinkage and creep at last.

scholarly journals PC Cable-Stayed Bridge Main Girder Shear Lag Effects: Assessment of Single Cable Plane in Construction Stage

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yan-feng Li ◽  
Xing-long Sun ◽  
Long-sheng Bao
Keyword(s):  
Bending Moment ◽  
Main Beam ◽  
Shear Lag ◽  
Distribution Law ◽  
Element Analysis ◽  
Cable Stayed Bridge ◽  
Action Point ◽  
Cable Force ◽  
Beam Section ◽  
Cable Forces

A model test and finite element analysis were conducted in this study to determine the distribution law of shear lag effect in the main beam section, a box girder, during the cable-stayed bridge construction process. The experimental and theoretical results were compared in an example of loading the control section. The stress value of the cable tension area of the main beam upper edge was found to markedly change when tensiling the cable force and was accompanied by prominent shear lag effect. After a hanging basket load was applied, the main beam of certain sections showed alternating positive and negative shear lag characteristics. The shear lag distribution law in the box girder of the single-cable-plane prestressed concrete cable-stayed bridge along the longitudinal direction was determined in order to observe the stress distribution of the girder. The results show that finite element analysis of the plane bar system should be conducted at different positions in the bridge under construction; the calculated shear lag coefficient of the cable force acting at the cable end of the cantilever reflects the actual force. In the beam segments between the cable forces, the shear lag coefficient determined by the ratio of the bending moment to the axial force reflects the actual stress at the cable force action point. In the midspan beam section between the action points of cable forces, the shear lag coefficient of the bending moment reflects the actual stress. The section shear lag coefficient can be obtained by linear interpolation of the beam section between the cable action point and the middle of the span.

scholarly journals A practical creep model for concrete elements under eccentric compression

2019 ◽  
Vol 52 (6) ◽  
Author(s):  
Haidong Huang ◽  
Reyes Garcia ◽  
Shan-Shan Huang ◽  
Maurizio Guadagnini ◽  
Kypros Pilakoutas
Keyword(s):  
Prestressed Concrete ◽  
Creep Behaviour ◽  
Concrete Structures ◽  
Creep Model ◽  
Small Scale ◽  
Compressive Creep ◽  
Eccentric Compression ◽  
Shrinkage And Creep ◽  
Concrete Elements

AbstractMany prestressed concrete bridges are reported to suffer from excessive vertical deflections and cracking during their service life. Creep softens the structure significantly, and therefore an accurate prediction of creep is necessary to determine long-term deflections in elements under eccentric axial compression such as prestressed concrete girders. This study proposes a modification to the creep damage model of Model Code 2010 to account for the effect of load eccentricity. The modified creep model considers damage due to differential drying shrinkage. Initially, the creep behaviour of small scale concrete specimens under eccentric compression load is investigated experimentally. Twelve small-scale concrete prisms were subjected to eccentric axial loading to assess their shrinkage and creep behaviour. The main parameters investigated include the load eccentricity and exposure conditions. Based on the experimental results, an inverse analysis is conducted to determine the main parameters of the modified creep model. Subsequently, a numerical hygro-mechanical simulation is carried out to examine the effect of load eccentricity on the development of shrinkage and creep, and on the interaction between drying, damage and creep. The results indicate that eccentric loading leads to different tensile and compressive creep through the cross section, which contradicts the current design approach that assumes that tensile and compressive creep are identical. The proposed model also predicts accurately the long-term behaviour of tests on reinforced concrete elements available in the literature. This study contributes towards further understanding of the long-term behaviour of concrete structures, and towards the development of advanced creep models for the design/assessment of concrete structures.

Shrinkage and Creep of Concrete on the Mechanical Properties of Cable-Stayed Bridge

2012 ◽  
Vol 594-597 ◽  
pp. 1498-1503
Author(s):  
Heng Shan Gao ◽  
Tie Ying Li
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Element Model ◽  
Main Beam ◽  
Construction Process ◽  
Analysis Software ◽  
Element Analysis ◽  
Concrete Shrinkage ◽  
Cable Stayed Bridge ◽  
Shrinkage And Creep

In this paper, using the universal finite element analysis software SAP2000 to build a large span cable-stayed bridge with finite element model, using a stepwise analysis finite element method to study the concrete shrinkage and creep efforts on the main beam inner force and deformation, cable tension during the cable-stayed bridge construction process and after the bridge. Research results show that the effects of shrinkage and creep in the finished bridge cannot be ignored, and the results can be used as reference for the design of similar projects.

Novelty detection of cable-stayed bridges based on cable force correlation exploration using spatiotemporal graph convolutional networks

2021 ◽  
pp. 147592172098866
Author(s):  
Shunlong Li ◽  
Jin Niu ◽  
Zhonglong Li
Keyword(s):  
Novelty Detection ◽  
The State ◽  
Spatial Dependency ◽  
Sensor Fault ◽  
Spatiotemporal Model ◽  
Convolutional Networks ◽  
Cable Stayed Bridge ◽  
Adjacency Matrices ◽  
Cable Forces ◽  
Cable Stayed Bridges

The novelty detection of bridges using monitoring data is an effective technique for diagnosing structural changes and possible damages, providing a critical basis for assessing the structural states of bridges. As cable forces describe the state of cable-stayed bridges, a novelty detection method was developed in this study using spatiotemporal graph convolutional networks by analysing spatiotemporal correlations among cable forces determined from different cable dynamometers. The spatial dependency of the sensor network was represented as a directed graph with cable dynamometers as vertices, and a graph convolutional network with learnable adjacency matrices was used to capture the spatial dependency of the locally connected vertices. A one-dimensional convolutional neural network was operated along the time axis to capture the temporal dependency. Sensor faults and structural variations could be distinguished based on the local or global anomalies of the spatiotemporal model parameters. Faulty sensors were detected and isolated using weighted adjacency matrices along with diagnostic indicators of the model residuals. After eliminating the effect of the sensor fault, the underlying variations in the state of the cable-stayed bridge could be determined based on the changing data patterns of the spatiotemporal model. The application of the proposed method to a long-span cable-stayed bridge demonstrates its effectiveness in sensor fault localization and structural variation detection.

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