Fatigue investigation of a railway truss bridge

1984 ◽  
Vol 11 (3) ◽  
pp. 625-631 ◽  
Author(s):  
Z. L. Szeliski ◽  
I. A. Elkholy
Keyword(s):  
Theoretical Model ◽  
Sample Size ◽  
Fatigue Damage ◽  
Field Measurement ◽  
High Strength ◽  
Traffic Analysis ◽  
Model Analysis ◽  
Remaining Life ◽  
Repetitive Loading ◽  
Truss Bridge

The advent of unit trains and high gross tonnage has made it necessary to evaluate the effect of repetitive loading on bridges. A description of a fatigue investigation of a 35.7 m (117 ft) railway through truss span is presented. The study consisted of (1) field measurement; (2) theoretical model analysis; (3) traffic analysis; (4) estimate of fatigue damage; (5) evaluation of fatigue detail category; (6) estimate of remaining life; and (7) action required. The effect of car sequence in trains, sample size, flat wheels, and impact on level of stresses is examined. As a result of the study, the trusses were retrofitted by removing rivets, reaming holes, and placing high-strength bolts.

Theoretical Model for Interfacial Nonlinear Bond Softening Behavior between Embedded Steel and HSHPC

2007 ◽  
Vol 348-349 ◽  
pp. 845-848
Author(s):  
Shan Suo Zheng ◽  
Lei Li ◽  
Guo Zhuan Deng ◽  
Shun Li Che ◽  
Wei Zhao
Keyword(s):  
Theoretical Model ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Nonlinear Process ◽  
Experimental Results ◽  
Interfacial Bond ◽  
Bond Slip ◽  
Softening Behavior ◽  
Bond Softening

The latest experimental study on steel reinforced high strength and high performance concrete (SRHSHPC) specimens shows that there exists interfacial bond softening phenomenon between embedded steel and high strength and high performance concrete (HSHPC), and it makes the shear transfer capacity between shaped steel and HSHPC be progressively reduced. To predict failure load in design, a theoretical model for interfacial bond softening behavior is required. As interfacial bond softening behavior is a nonlinear process involving material properties, it can be analyzed once the relation of interfacial bond stress (τ ) and slippage ( s ) is known. In this paper, the mechanism of interfacial bond-slip is studied, thus a simplified τ − s relation including ascending and descending parts is proposed and employed to analyze the interfacial nonlinear bond-slip process. Based on the interfacial equilibrium between steel and HSHPC as well as the τ − s relation, the basic governing equations in both softened region and elastic region are established and solved for steel strain or stress. At last, the application of the model is verified through comparison with experimental results. The calculating results of the model are found to be in good agreement with experimental results, showing that the model can describe the bond-slip process in real material systems.

scholarly journals Theoretical and Experimental Study on the Antisliding Performance of Casting Steel Cable Clamps

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Yangjie Ruan ◽  
Bin Luo ◽  
Mingmin Ding ◽  
Lifan Huang ◽  
Zhengxing Guo
Keyword(s):  
Theoretical Model ◽  
Transversely Isotropic ◽  
High Strength ◽  
Clamping Force ◽  
Steel Cable ◽  
Cable Tension ◽  
Bolt Preload ◽  
Term Creep ◽  
Casting Steel

For large-span cable structures, a cable clamp is a key joint that connects adjacent structural components. In general, the antisliding performance of cable clamps determines their resistance capacity, and the antisliding force is generated by the clamping force induced by the high-strength bolts and the contact surfaces between the cable and the clamp. Since the existing methods are not sufficiently comprehensive for use to predict the precise bolt preload, a theoretical model developed by considering transversely isotropic material and the generalized Hook’s law is presented to predict the attenuation values of the bolt clamping force and the corresponding parameters. Then, to meet the requirements of Eurocode 3, a new laboratory test is performed to reveal the antisliding mechanism of cable clamps, considering the effects of long-term creep and cable tension. According to the results of the data collected by real-time monitoring, the actual ultimate antisliding force of the clamp and the comprehensive friction coefficient are determined. Finally, a comparative study between the theoretical results and the experimental results is conducted. The proposed theoretical model can predict the actual attenuation of the bolt clamping force after cable tension. The results show that the stiffness of the clamp plate should be minimized when designing the clamp to reduce the loss of the bolt preload.

scholarly journals THEORETICAL MODEL FOR DOUBLE-SKINNED CONCRETE-FILLEDSTEEL-TUBULAR COLUMNS WITH EXTERNAL CONFINEMENT

2015 ◽  
Vol 21 (5) ◽  
pp. 666-676 ◽  
Author(s):  
Chun Xiao Dong ◽  
Johnny Ching Ming Ho
Keyword(s):  
Theoretical Model ◽  
High Strength Concrete ◽  
High Strength ◽  
Imperfect Interface ◽  
Steel Tube ◽  
Interface Bonding ◽  
Strength Concrete ◽  
Tubular Columns ◽  
Strength And Stiffness ◽  
Transverse Steel

Recent advances in the production of super-fine cement and filler technology has made the production of high-strength concrete (HSC) of 120 MPa practicable in the industry. Nonetheless, the application of such HSC in real construction is still limited. One of the reasons that inhibits the use of HSC is the brittleness, which causes HSC structures to fail explosively if the concrete confinement is not adequate. The traditional method of installing transverse steel as confinement is not feasible in HSC structures, as the steel will be too congested to ensure proper concrete placing. To overcome the problem, double-skinned high-strength concrete-filled-steel-tubular (HSCFST) columns has been advocated, which could provide large, continuous and uniform confinement to HSC. However, a major shortcoming of the double-skinned HSCFST columns is the imperfect interface bonding that occurs at the elastic stage that reduces the elastic strength and stiffness of columns. To improve the situation, the authors have verified previously that using external steel rings on the outer steel tube can successfully restrict the dilation of HSCFST columns and thus restore an intact interface bonding condition. As a continued study, the authors will in this paper develop a theoretical model for predicting the uni-axial load-carrying capacity of doubled-skinned HSCFST columns.

scholarly journals Research on Fatigue Damage in High-Strength Steel (FV520B) Using Nonlinear Ultrasonic Testing

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Bingbing Chen ◽  
Chao Wang ◽  
Pengfei Wang ◽  
Sanlong Zheng ◽  
Weiming Sun
Keyword(s):  
Fatigue Damage ◽  
High Strength Steel ◽  
Main Crack ◽  
Lamb Waves ◽  
High Strength ◽  
Nonlinear Parameter ◽  
Damage State ◽  
Nonlinear Parameters ◽  
Highly Sensitive ◽  
Nonlinear Ultrasonic

In view of the early fatigue damage of high-strength steel FV520B, a nonlinear ultrasonic detection was performed on two types of fatigue samples using nonlinear Lamb waves. The experimental results indicated that the ultrasonic nonlinear parameter is highly sensitive to early fatigue damage in high-strength FV520B. For plate specimens, the ultrasonic nonlinear parameter increased with the number of fatigue cycles. Scanning electron microscopy (SEM) observations of the fatigue specimens revealed that as the number of fatigue cycles increased, the microstructure of the material gradually deteriorated, and the ultrasonic nonlinear parameter increased. For notched specimens, the ultrasonic nonlinear parameter increased as the size of the main crack increased. SEM observations of the fracture indicated that the ultrasonic nonlinear parameters were more consistent with the equivalent microcrack length (defined as the sum of microcrack lengths in the statistical area), as compared with the length of the main crack. It was determined that the nonlinear effect of the Lamb wave is related to the equivalent microcrack length inside the material and that the ultrasonic nonlinear parameter can effectively characterize the fatigue damage state of high-strength FV520B.

Research on Dynamic Design Method Based on Measuring Information for Printing Press

2010 ◽  
Vol 174 ◽  
pp. 290-294
Author(s):  
Yi Ming Wang ◽  
Bang She Chen ◽  
Yan Li ◽  
Shao Hua Zhang
Keyword(s):  
Theoretical Model ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Design Method ◽  
Model Analysis ◽  
Printing Press ◽  
Vibration Measurement ◽  
Dynamic Design ◽  
Analysis Experiment ◽  
Printing Machine

Printing machinery’s reliability is one of the most important index parameter and good dynamic characteristics are essential for high speed printing press. The dynamic characteristic is predictable for printing machine with dynamic design. With the complexity of printing technique and printing machine, information, such as load on components is lack, leading to the difficulty of dynamic model solving and further more the dynamic parameters needs to be verified. Firstly, according to the dynamic design method, a dynamic design process based on measuring information for printing machine was put forward. Secondly, on the basis of principle and structure analysis to typical printing machine, dynamic characteristics measurement item and method was determined. With a wallboard of a two-color offset press acting as an example, the utilizing method was illustrated through dynamic modeling, theoretical model analysis, experiment model analysis based on vibration measurement and comparing the theoretical and experimental results. Finally, a Dynamic Design Assistant Platform based Vibration Measurement for Printing Machine was developed and had been used in 10 kinds of printing machine measurement and analysis. The conclusion shows that the tolerance of the theoretical model analysis results and experiment results is allowed. A new approach for new printing machine design and optimal design for existed printing machine is given.

Remaining life estimation by fatigue damage sensor

2010 ◽  
Vol 163 (1) ◽  
pp. 3-11 ◽  
Author(s):  
K. Nihei ◽  
O. Muragishi ◽  
T. Kobayashi ◽  
K. Ohgaki ◽  
A. Umeda
Keyword(s):  
Fatigue Damage ◽  
Remaining Life ◽  
Life Estimation
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