scholarly journals Long-Term Settlement of High Concrete-Face Rockfill Dam by Field Monitoring and Numerical Simulation

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Xinjie Zhou ◽  
Xinjian Sun ◽  
Junxing Zheng ◽  
Haoyuan Jiang ◽  
Yongye Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Creep Deformation ◽  
Deformation Behavior ◽  
Finite Element Software ◽  
Rockfill Materials ◽  
Stress And Deformation ◽  
Long Term Performance ◽  
Term Performance ◽  
Concrete Face

High concrete-face rockfill dams (CFRDs) with heights of over 100 m have been quickly developed in recent years. The self-weight of rockfill materials causes creep deformation of the dam body. However, the creep analysis method of high CFRDs in finite element software is few, and sometimes, it can also not reflect the long-term performance of high CFRDs well. Therefore, it is necessary to carry out the secondary development in finite element software. This study developed a subroutine that can run in Finite Element Method (FEM) platform ABAQUS to simulate long-term creep deformation behavior of the rockfill materials more accurately. Then, a displacement back-analysis for parameters, based on the Xujixia high CFRD project, is performed by the neural network response surface method (BP-MPGA/MPGA). Remarkable agreements are observed between simulation and field monitoring results. The calibrated FEM model is used to predict stress and deformation behavior of the Xujixia high CFRD after three years of operation period. The result indicates that rockfill creep deformation has a significant impact on stress and deformation of the high CFRD during the operation. This research may predict long-term performance using FEM in the design stage for high CFRDs.

A new test method for evaluating the long-term performance of fiber-reinforced concrete pipes

2019 ◽  
Vol 23 (7) ◽  
pp. 1336-1349 ◽  
Author(s):  
Fouad T Al Rikabi ◽  
Shad M Sargand ◽  
Issam Khoury ◽  
John Kurdziel
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Steel Reinforcement ◽  
Fiber Reinforced Concrete ◽  
Synthetic Fiber ◽  
Concrete Pipes ◽  
Concrete Pipe ◽  
Long Term Performance ◽  
Term Performance

Synthetic fibers have been used recently to minimize the need for steel reinforcement in the concrete pipe to enhance their ductility. However, synthetic fiber has properties that may change over time due to its viscoelastic behavior. The objective of this study is to investigate the long-term performance of fiber-reinforced concrete pipes using a new test frame. A three-dimensional finite element model was created for the long-term testing frame to ensure its compliance with the American Society for Testing and Materials requirement. The finite element results showed that the testing frame successfully transferred the load to the concrete as the pipe cracked at the location where high flexural stresses are expected. Concrete pipe reinforced with synthetic fiber dosage of 9 kg/m3 along the steel reinforcement area of 5.7 cm2/m was tested to evaluate the concrete pipe system performance. The pipe was tested under two load stages for 120 days each. Load stages 1 and 2 included applying 40% and 70% of the ultimate load obtained by the authors in a previous study, respectively. The strain and deflection increased linearly within 5 days of applying the load and then leveled off. The pipe showed a slight increase in the crack width and deflection, indicating that fiber creep did not have a significant impact on the long-term performance of the concrete pipe. Also, it was observed that strain values surpassed those for plain concrete material, suggesting that including synthetic fiber in the concrete pipe mix enhanced the pipe ductility.

Three-Dimensional Nonlinear Finite Element Analysis on the Concrete Face Cock-Fill Dam of TianChi Upper Reservoir

2013 ◽  
Vol 838-841 ◽  
pp. 1763-1767
Author(s):  
Shuang Mei Chang ◽  
Wen She He ◽  
Yu Qiang Cheng ◽  
Su Min Zhao
Keyword(s):  
Finite Element ◽  
Water Pressure ◽  
Three Dimensional ◽  
Elastic Model ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Stress And Deformation ◽  
Three Dimensional Finite Element ◽  
Nonlinear Elastic ◽  
Concrete Face

Taking the concrete face cock-fill dam upper reservoir of Tianchi as an example, the stress and deformation characteristics of concrete face rock-fill dam are studied in-depth in this paper. The article builds a fine three-dimensional finite element model of Tianchi upper reservoir by a nonlinear elastic model of the finite element software ADINA. The stress and deformation of the two conditions under completion and storage for the dam are calculated ,which will be analyzed to obtain stress - strain distribution of the dam in two conditions, comparing dam stress and deformation before and after impoundment to get impact of the water pressure on the dam stress and deformation: comparing after impoundment and completion , the dam water level displacement of upstream side from role of horizontal water pressure will increase , the dam upstream offsets to downstream , but the offset is little ; Due to dam is affected by vertical hydrostatic pressure and uplift pressure after impoundment , the dam settlement is slightly less than the completion in storage. KEY WORDS: Tianchi upper reservoir, The concrete face cock-fill dam, Three-dimensional finite element, Nonlinear elastic model, Analysis of stress and deformation

Long-Term Performance of Steel-Concrete Composite Box Girder

2013 ◽  
Vol 838-841 ◽  
pp. 653-656
Author(s):  
Xiao Jie Liu ◽  
Ya Peng Jiang
Keyword(s):  
Initial Time ◽  
Time Varying ◽  
Box Girder ◽  
Stress And Deformation ◽  
Long Term Performance ◽  
Term Performance

In this paper, an analytical example was given to show the time-varying regularity of stress and deformation of composite box girder. The distribution of deflection along the span at initial time and ultimate time was calculated. It was found that the mid-span deflection increased rapidly during the initial 50 days, and became stable after 300 days. The stress of steel increased while the stress of concrete decreased and both of the variation rates gradually slowed down with time. The regularity of stress of steel and concrete with time are similar to that of the mid-span deflection.

Strain-Based Design Methods for Composite Repair Systems

2008 ◽  
Author(s):  
Chris Alexander
Keyword(s):  
Finite Element ◽  
Composite Materials ◽  
Design Method ◽  
Design Methods ◽  
Strain Gages ◽  
Composite Repair ◽  
Reinforced Steel ◽  
Long Term Performance ◽  
Term Performance

Composite materials are commonly used to repair corroded and mechanically-damaged pipelines. Most of these repairs are made on straight sections of pipe. However, from time to time repairs on complex geometries such as elbows, tees, and field bends are required. Conventional design methods for determining the amount of required composite materials are not conducive for these types of repairs. Over the past several years, the author has developed a methodology for assessing the level of reinforcement provided by composite materials to damaged pipelines using finite element methods. Instead of stress as the design basis metric, the method employs a strain-based design criteria that is ideally-suited for evaluating the level of reinforcement provided to non-standard pipe geometries. The finite element work has been validated using experimental methods that employed strain gages placed beneath the composite repair to quantify the level of reinforcement provided by the repair. This paper provides a detailed description of the strain-based design method along with appropriate design margins for both the reinforced steel and long-term performance of the composite materials.

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.

An Experimental Study on the Frictional Property and Long-Term Performance of GT/HDPE Composites

2007 ◽  
Vol 539-543 ◽  
pp. 1043-1046
Author(s):  
Jung Min Seo ◽  
Han Yong Jeon ◽  
Beong Bok Hwang ◽  
Y.H. Lee ◽  
H.S. Koo
Keyword(s):  
Experimental Study ◽  
Creep Deformation ◽  
High Performance ◽  
Reduction Factor ◽  
Frictional Property ◽  
Needle Punching ◽  
Punching Process ◽  
Long Term Performance ◽  
Term Performance

This paper is concerned with the long-term performance of geo-textile (GT) composites in terms of creep deformation and frictional properties. Composites of PVA GT and HDPE GM were made to investigate the advanced properties of long-term performance related to waste landfill applications. The same experiments were also performed for typical polypropylene and polyester GT and compared to PVA GT/HDPE GM composites. The main purpose of this study is to develop high performance GT composites with GM by using PVA GT which is capable of improving frictional property and thus enhances long-term performance of GT composites. In the present experiments, GT composites of PVA GT/HDPE GM, PVA GT of 600, 1000, 1500, 2000g/m2 and HDPE GM were prepared in thermal bonding process. Polyester and polypropylene GT were also made in needle punching process. The creep deformation of GT composites was measured and evaluated in accordance with ASTM D5262. Frictional characteristics of GT composites tested in this study were conducted with compact direct shear apparatus in accordance with ASTM D5321. It was concluded from the present experimental study that friction coefficient of GT composites is relatively large compared with those of polyester and polypropylene non-woven GT as long as the friction media has similar size to the particles of domestic standard earth. In the event that 20% of the maximum tensile strength was added to polypropylene and polyester non-woven geo-textiles, creep deformation reached to 10% or higher, making it even impossible to find reduction factor.

Fine Particle Mass Monitoring with Low-Cost Sensors: Corrections and Long-Term Performance Evaluation

2019 ◽  
Author(s):  
Carl Malings ◽  
Rebecca Tanzer ◽  
Aliaksei Hauryliuk ◽  
Provat K. Saha ◽  
Allen L. Robinson ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Fine Particle ◽  
Low Cost ◽  
Particle Mass ◽  
Long Term Performance ◽  
Term Performance
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