scholarly journals Long-Term Deflection of Prestressed Concrete Bridge Considering Nonuniform Shrinkage and Crack Propagation by Equivalent Load Approach

2020 ◽  
Vol 10 (21) ◽  
pp. 7754
Author(s):  
Fiseha Nega Birhane ◽  
Sung-Il Kim ◽  
Seung Yup Jang
Keyword(s):  
Prestressed Concrete ◽  
Three Dimensional ◽  
Simplified Approach ◽  
Long Span Bridges ◽  
Long Span ◽  
Dimensional Finite Element ◽  
Current Design ◽  
Equivalent Load ◽  
Three Dimensional Finite Element

Long-span prestressed concrete (PSC) bridges often suffer excessive deflection during their service lives. The nonuniform shrinkage strains of concrete caused by uneven moisture distributions can induce significant additional deflections, when combined with the creep and cracking of the concrete. Current design practices usually overlook these factors, and the few proposed approaches to consider them are complex and computationally expensive. This study proposes a simplified approach for considering the effect of nonuniform shrinkage by using the equivalent load concept in combination with a nonlinear analysis of the creep and cracking using three-dimensional finite element models. The long-term deflections of short-, medium-, and long-span PSC bridges are calculated under the combined effects of creep, shrinkage, and cracking. The results show that the nonuniform shrinkage effect is significant in medium- to long-span bridges, and that the cracking of the concrete reduces the stiffness, thereby increasing the long-term deflection of the bridges (more severely so in combination with creep and shrinkage). The predicted long-term deflections reasonably agree with the measured data. Thus, the equivalent load approach is effective for calculating long-term deflections considering nonuniform shrinkage strains, without the complicated and expensive coupling of moisture transport and structural analyses.

Effect of truck position and multiple truck loading on response of long-span metal culverts

2014 ◽  
Vol 51 (2) ◽  
pp. 196-207 ◽  
Author(s):  
Tamer M. Elshimi ◽  
Richard W.I. Brachman ◽  
Ian D. Moore
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shell Theory ◽  
Orthotropic Shell ◽  
Three Dimensional ◽  
Element Analysis ◽  
Long Span ◽  
Dimensional Finite Element ◽  
Current Design ◽  
Three Dimensional Finite Element

Long-span metal culverts have been used for almost 50 years as an economical alternative to short-span bridges. Current design methods are based on two-dimensional finite element analysis using beam theory to represent the structure, or three-dimensional analysis employing orthotropic shell theory. However, neither analysis has been used to investigate the most critical position for trucks at the surface of long-span metal culverts. This paper shows results of three-dimensional finite element analysis, employing orthotropic shell theory and explicitly modeling the geometry of corrugated plates for a specific box culvert tested using a fully loaded dump truck. The analysis was then extended to study the effect of truck position on the response of long-span box and arch culverts. The finite element models, employing orthotropic shell theory and explicitly modeling the geometry of corrugated plates, successfully produced the behaviour of the culvert under truck loading for different truck positions. Culvert deformations were calculated within 7%–13% of the measured values at different locations. The bending moment at the crown was within 4%–17% of the values calculated using the measured strains. If three-dimensional finite element analysis is used to design these culverts, two design trucks should be considered (current design considers a single design truck). The highest moment or thrust is obtained when the truck tandem axles are located above the crown of the culvert.

Three Dimensional Numerical Analyses of Bridge Piled-Raft Foundation under Riverbed Erosion

2012 ◽  
Vol 178-181 ◽  
pp. 2373-2377 ◽  
Author(s):  
Wen Tsung Liu ◽  
Yi Yi Li
Keyword(s):  
Bearing Capacity ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Bridge Piers ◽  
Piled Raft Foundation ◽  
River Erosion ◽  
Dimensional Finite Element ◽  
The Face ◽  
Three Dimensional Finite Element

From the 921 earthquake to the major typhoons, including the Morakot typhoon, they damaged original landscape of rivers in Taiwan. In recent years, it alleged that abutment bridge exposed to the most serious security problems. Because of bridge piers in addition to the face of long-term river erosion, the flood on the pier will produce localized erosion near the bridge. The pier will be due to inadequate bearing capacity, resulting in subsidence, displacement, bridge version accompanied by tilting and even caving. The river erosion of soil around the piers deposits and production of contraction will often reduce the bearing capacity. Therefore, how to accurately estimate the scour depth, calculate piers to withstand water impact and analyses its stability for preventing injuries in the first place is the current pressing issues. In this study, three-dimensional finite element method (FEM) analysis program Plaxis 3D foundation is used. Polaris second bridge is selected for analysis. Based on local scouring of the model and various numerical variable conditions, the parameter of bridge pier is studied.

Comparative Analysis of Several Construction Scheme of a Large-Sized Tie-Arch Aqueduct

2011 ◽  
Vol 94-96 ◽  
pp. 2350-2354
Author(s):  
Shu Zhong Lei ◽  
Zhong Xin Wang ◽  
Jian Ting Xu ◽  
Chi Peng Liu
Keyword(s):  
Comparative Analysis ◽  
Prestressed Concrete ◽  
Three Dimensional ◽  
Stability Control ◽  
River Diversion ◽  
Finite Element Program ◽  
Dimensional Finite Element ◽  
Element Program ◽  
Stress And Deformation ◽  
Three Dimensional Finite Element

An aqueduct of larger-span prestressed concrete arch structure for river diversion project is located in coastal areas, and raises difficult questions on deformation and stability control of the construction process due to greater wind load and poor soil. Due to the limited width of bracket erection, this paper put forward five possible construction schemes, and does the comparative analysis using three-dimensional finite element program, and gets the economic and reasonable one. Finally conduct a pressure test after the bracket erection, and verify the analysis results using measured stress and deformation data.

scholarly journals Fatigue Behavior of Prestressed Concrete Beam for Straddle-Type Monorail Tracks

2018 ◽  
Vol 8 (7) ◽  
pp. 1136 ◽  
Author(s):  
Qianhui Pu ◽  
Hanyu Wang ◽  
Hongye Gou ◽  
Yi Bao ◽  
Meng Yan
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beam ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Element Model ◽  
Transportation Systems ◽  
Traffic Load ◽  
Prestressed Concrete Beam ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Monorail transportation systems are widely built in medium and small cities, as well as hilly cities, because of their excellent performance. A prestressed concrete track beam is a key load-carrying structural component and guideway subjected to repeated traffic load. The fatigue behavior of the prestressed concrete beam is critical for the safety of the transportation system. This paper presents the results of an experimental study on the fatigue behavior of a prestressed concrete beam in terms of stiffness degradation and strain change. The displacement and rotation of the beam of concrete and reinforcement were examined, respectively. A three-dimensional finite element model was established to help understand the development of the mechanical behavior. No crack was observed throughout the test. Both concrete and bars behaved in their linear-elastic stage throughout the test, and the bond between them performed well.

The Characteristic of Prestressed Concrete Pier Seismic Crack

2014 ◽  
Vol 501-504 ◽  
pp. 1628-1632
Author(s):  
Hui Li Wang ◽  
Hong Wang ◽  
Si Feng Qin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Prestressed Concrete ◽  
Three Dimensional ◽  
Element Model ◽  
Dimensional Finite Element ◽  
Tensile Zone ◽  
Three Dimensional Finite Element ◽  
Prestressed Reinforcement

Through three dimensional finite element analyzes, overall cast-in-place prestressed concrete pier seismic crack characteristic is researched. The separation formula finite element model is established by means of bilinear reinforce model and Kent-R.Park concretes model, without considering slip between concretes and. reinforce. It compares and analyzes the seismic crack characteristic between prestressed concrete pier and reinforcement concretes pier. The results show that the prestressed reinforcement can reduce the tensile zone of concrete, put off the appearance of cracks, improved the stiffness of pier, and reduced the top displacement.

Simulation-Based Study of Impact Energy Absorption in American Football Helmet

2016 ◽  
Author(s):  
Seyed Saeed Ahmadisoleymani ◽  
James Yang ◽  
Andrew Schmit ◽  
Jahan Rasty
Keyword(s):  
Three Dimensional ◽  
American Football ◽  
Fe Model ◽  
Revolution Speed ◽  
Football Helmet ◽  
Simulation Based ◽  
Dimensional Finite Element ◽  
Energy Absorbing ◽  
Three Dimensional Finite Element

Concussion injury limits the American football player’s career life and causes several long term problems. In order to limit its severity and frequency, various helmets have been designed to protect player’s head. This absorbency is mainly achieved by the padding system inside the helmet which includes energy absorbing and comfort foams and inflatable air surrounding the foams. In a recent study an experiment was performed on a Riddell Youth Revolution Speed helmet to analyze the effect of the head size on capability of the helmet in attenuating the impacts. It was found that headform size would affect the helmet performance. In the current study, a three dimensional finite element (FE) model has been developed based on the above mentioned experiment. The purpose of this study is to develop and validate the FE model based on the experimental results, regarding the effect of headform size on performance of the helmet.

scholarly journals ANALYSIS OF THE COMBINATION OF METHODS OF FASTENING THE JUNCTION POINT OF A HORIZONTAL TUNNEL WITH A VERTICAL SHAFT IN CONDITIONS OF DENSE URBAN DEVELOPMENT

2021 ◽  
pp. 108-115
Author(s):  
S. M. STOVPNYK ◽  
H. K. TUHANOV
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Urban Development ◽  
Three Dimensional ◽  
Digital Modeling ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
The Impact ◽  
Element Method

Purpose. The problem of compares the long-term behavior of a tunnel-well taking into account the rigid and flexible couplings in the projected structures in Ukraine with 3d digital modeling using the three-dimensional finite element method. A refined geotechnical model has also been developed, taking into account the nature of the piezometric starting conditions and the proposed piezometric conditions for assessing the long-term condition as well as a summary of the properties and dimensions of the tunnel and the shaft. Methodology. Analysis of structural connections based on the experience of building shallow subways in dense urban development on the example of construction projects in China and Mexico. Search for the optimal combination of implemented methods to achieve the optimal result. Problems of a choice of a mode with 3d digital modeling using the three-dimensional finite element method based on two assumptions; the first assumption considers the rigid connection as a monolithic concrete structure between the shaft wall and the tunnel body, and the second assumption considers a material with elastic behavior between the two structures, which in turn leads to a flexible connection. The main parameters that must be clarified and corrected by the designer of the system during commissioning are determined. Next, the soft soil model was used to perform the analyzes with end elements for compressible layers. Findings. Simulation in the application, the Plaxis software environment obtained graphs of transients for the most important operating parameters, such as the geometry of the tunnel and the indicated lining, the flotation pool, three-dimensional clusters. Originality. Scientific interest in advancing technologies used in combination. Development of an algorithm for the optimal selection of the parameters of flexibility and durability in specific conditions, to save time and simplify the calculation forms. Practical value. The analysis of the obtained results is carried out, the main focus was on the relative loads and stress concentrations in the connecting elements, namely the stresses that occur in the transverse direction of the joint. Also in articles were determined some of the advantages and disadvantages of the different connection alternatives are discussed in order to neutralize the impact of the case in the future.

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