scholarly journals Performance Deterioration of Heavy-Haul Railway Bridges under Fatigue Loading Monitored by a Multisensor System

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zhiwu Yu ◽  
Zhi Shan ◽  
Ju Yuan ◽  
Xiao Li
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Polymer Optical Fiber ◽  
Railway Bridges ◽  
Multisensor System ◽  
Linear Variable Displacement Transducer ◽  
Heavy Haul ◽  
Performance Deterioration ◽  
Heavy Haul Railway

Heavy-haul railway bridges play an increasingly essential role in the transportation in China due to the increasing transport volume. The performance deterioration of the scale models of a typical heavy-haul railway bridge under fatigue loading is monitored in this work, based on a multisensor system including the fiber-reinforced polymer optical fiber Bragg grating and electrical resistance strain gauges, linear variable displacement transducer, and accelerometer. Specifically, by monitoring/observing on the failure mode, fatigue life, load-midspan deflection response, material strain development, and so forth, this work develops an S-N model by comparing the relationship between fatigue life and rebar stress range with that between fatigue life and load level and proposes a damage evolution model considering the coupling of the stiffness degradation and inelastic deformation of specimens. It is found that the fatigue life of specimens is determined by the fatigue life of the rebar at the bottom and it may be lower than 2.0 million cycles with a 30-ton axle weight when environmental factors are taken into account. The predictions of the models agree well with experimental results. Therefore, this work furthers the understanding of the fatigue performance deterioration of the bridges by using a multisensor system.

Study on the stiffness degradation in concrete continuous beam with externally prestressed CFRP tendons under fatigue loading

2021 ◽  
pp. 136943322199249
Author(s):  
Xing Li ◽  
Jiwen Zhang ◽  
Jun Cheng
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Fiber Reinforced Polymer ◽  
Stiffness Degradation ◽  
Test Results ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Practical Engineering ◽  
Good Agreement

This paper presents fatigue behaviors and the stiffness degradation law of concrete continuous beams with external prestressed carbon fiber-reinforced polymer (CFRP) tendons. Three specimens were tested under fatigue loading, and the influence of different load levels on the stiffness degradation and fatigue life were studied, and it was found that the stiffness degradation of three test specimens exhibited a three-stage change rule, namely rapid decrease, stable degradation, and sharp decline, but there are obvious differences in the rate and amplitude of stiffness degradation. The load level has a significant influence on the fatigue life of the test specimens. An analytical model with load level considered was proposed to calculate the residual stiffness and predict the stiffness degradation, which is in good agreement with the test results. The model of stiffness degradation presents a possible solution for practical engineering applications of concrete continuous beams with externally prestressed CFRP tendons subjected to different fatigue loadings.

scholarly journals Study on Structural Service Performance of Heavy-Haul Railway Tunnel with Voided Base

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Zhiqiang Zhang ◽  
Bowen Zeng ◽  
Chaolong Dai ◽  
Wanping He
Keyword(s):  
Fatigue Life ◽  
Time History ◽  
Vertical Displacement ◽  
Surrounding Rock ◽  
Dynamic Loads ◽  
Vehicle Body ◽  
Monitoring Point ◽  
Heavy Haul ◽  
Heavy Haul Railway

The structural design of heavy-haul railway tunnels still follows the design method of ordinary railway tunnels. Most of them do not take into account the influence of large axle load of 30 t or more, let alone such problems as void of surrounding rock under long-term dynamic loads. In order to analyze the dynamic response of heavy-haul railway tunnels under long-term reciprocating cyclic dynamic loads, considering the factors such as axle load of vehicle body, unsprung mass, and track irregularity, the vibration load time-history curve of heavy-haul railway trains is determined, the three-dimensional dynamics coupling model of dynamic load-tunnel-surrounding rock is established, and the fatigue life of the structure under different void conditions is analyzed based on the S-N curve of concrete. According to the study, the loading, unloading, and vibration caused by train passing will lead to fluctuations in the vertical displacement response of the monitoring point. The peaks and valleys of the response time-history curve correspond to the effect of the train wheels rolling through. When the void is 6 m wide and 10 cm thick, the vertical displacement of the inverted arch is increased by about 9 times, the peak velocity of the inverted arch is increased by about 3.8 times, and the maximum principal stress is increased by about 47.3%, compared with the condition without void. With the same void thickness, the vertical displacement and velocity curves of the inverted arch vary significantly with the increase of the void width. The width of the base void has a significant effect on the fatigue life of the structure of heavy-haul railway tunnels. Based on the operation requirement of 100-year service life, the ultimate void width is 2 m.

Experimental Investigation of the UV Influence on the Fatigue Life of SLJ of CFRP/AL

2018 ◽  
Vol 10 (07) ◽  
pp. 1850071
Author(s):  
Salah Mahdi Khaleel ◽  
Tim Hilditch ◽  
Bernard Rolfe ◽  
Riyadh Al-Ameri
Keyword(s):  
Fatigue Life ◽  
Elevated Temperature ◽  
Real Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Exposure Level ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Single Lap Joint ◽  
Adhesively Bonded Joint

The adhesively bonded joint in most of applications is subjected to a complex formation of loading system and environmental conditions. Application such as cars, boats and airplanes are real-life examples of these types of complex systems. Therefore, evaluating the joint performance in contradiction of these types of loading are essential steps to understand the joint behavior in different working conditions. The current study attempts to investigate the influence of ultraviolet and elevated temperature as well as other loading parameters such as mean load and frequency on the fatigue life and fracture modes of adhesively bonded single lap joint of CFRP and Aluminum. Therefore, single lap joint samples prepared and exposed to different ultraviolet levels and exposure durations, then tested with constant amplitude fatigue at different load levels and frequencies. The main outcomes of this study show a 90% reduction in the fatigue life by increasing fatigue loading from 2[Formula: see text]kN to 5[Formula: see text]kN and there is a 29% reduction by increasing frequency from 5[Formula: see text]Hz to 15[Formula: see text]Hz for the same load level. While UV exposure level shows only 3–5% reduction compared to 8% reduction for the elevated temperature influence on fatigue life.

scholarly journals Dynamic Response of Railway Bridges under Heavy-Haul Freight Trains

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ye Xiao ◽  
Xiaoyong Luo ◽  
Jinhong Liu ◽  
Kun Wang
Keyword(s):  
Dynamic Response ◽  
Fe Model ◽  
Bridge Structure ◽  
Railway Bridge ◽  
Running Speed ◽  
Railway Bridges ◽  
Heavy Haul ◽  
Formation Number ◽  
Axle Loads ◽  
Heavy Haul Railway

In the freight railway bridge, the increase of the train running speed and train axle loads can enlarge dynamic response (DR) of the railway bridges, which leads to excessive vibration of bridges and endangers the structural safety. In this paper, a three-dimensional coupled finite element (FE) model of a heavy-haul freight train-track-bridge (HHFTTB) is established using multibody dynamics theory and FE method, and the DR for the coupled system of HHFTTB are solved by ABAQUS/Explicit dynamic analysis method. The field-measured data for a 32 m simply supported prestressed concrete beam of a heavy-haul railway in China are analyzed, and the validity of the FE model is verified. Finally, the effects of train formation number, train running speed, and train axle loads on DR of the heavy-haul railway bridge structures are studied. The results show that increasing the train formation number only has an influence on DR duration of the bridge structure, rather than the peak value of DR, when the train formation number exceeds a certain number; besides, the train axle loads and train running speed have significant influence on DR of the bridge structure. The results of this study can be used as reference for the design of heavy-haul railway bridges and the reinforcement transformation of existing railway bridges.

Field test and numerical analysis of Insulated rail joints in heavy-haul railway

2021 ◽  
Vol 298 ◽  
pp. 123905
Author(s):  
Hong Xiao ◽  
Guangpeng Liu ◽  
Dongwei Yan ◽  
Yue Zhao ◽  
Jiaqi Wang ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Field Test ◽  
Heavy Haul ◽  
Heavy Haul Railway
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