scholarly journals A Rapid Detection Method for Bridges Based on Impact Coefficient of Standard Bumping

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Xiaolan Liu ◽  
Xianmin Zhang ◽  
Yadong Wang

The evaluation method of load transfer efficiency using falling weight deflectometer is unworkable in remote mountain areas and transportation difficult region. Therefore, a novation method of load transfer efficiency evaluation is proposed using the index of amplitude ratio. Finite element method is applied to study the influence of dowel bar parameters (diameter, length, spacing, and elastic modulus) and pavement structures parameters (thickness and modulus) on load transfer efficiency, frequency, and the ratio of amplitude. Results of finite element model show that the effects of dowel bar and pavement structure parameters on load transfer efficiency and the ratio of amplitude are similar. The load transfer efficiency, frequency, and the ratio of amplitude enhance with the increase of dowel bar diameter, length, and elastic modulus and the decrease of dowel bar spacing. The subgrade modulus has more significant influence on the load transfer efficiency, frequency, and the ratio of amplitude than other pavement parameters. Polynomial function method is utilized to established load transfer mode between deflection-based load transfer efficiency and the ratio of amplitude. The feasibility and reliability of new method is verified by static and dynamic load test. All results are helpful for the development of highway engineering and airport engineering.

2012 ◽  
Vol 178-181 ◽  
pp. 1152-1155 ◽  
Author(s):  
Luo Ke Li ◽  
Yun Liang Li ◽  
Yi Qiu Tan ◽  
Zhong Jun Xue

In a jointed plain concrete pavements, the dowel bar system are used to provide lateral load transfer across transverse joint. Corrosion of commonly used steel dowel in engineering practice reduces their service life and costs considerable maintenance and repair spending for concrete pavements. The objective of this study focus primarily on the performance of none eroded GFRP dowel on LTE( load transfer efficiency) with the help of a three-dimensional finite-element model. The amount of LTE can be obtained directly from comparing the maximum deflection of the concrete slab and the level tensile stress under the concrete slab. According to the finite element results, the larger-diameter GFRP dowel are found to perform the best in this study.


2013 ◽  
Vol 857 ◽  
pp. 160-165
Author(s):  
Peng Peng ◽  
Bo Tian ◽  
Xiu Xiong Mo ◽  
Kai Min Niu

Finite element model analysis was performed with respect to patterns of load transfer relying on the action of aggregate interlocking and on the concurrent action of aggregate interlocking and dowel bars. The best timing for dowel bar retrofit was determined by way of increase in load transfer efficiency and maximum tensile stress borne at joints. The situation of dowel bar retrofit to restore load transfer efficiency was verified by way of onsite tests and economic analysis performed before we came to the conclusion that the way of dowel bar retrofit to restore load transfer efficiency is fairly cost effective. The construction technique of dowel bar retrofit to restore load transfer efficiency is finally summarized in light of engineering practice.


2020 ◽  
Vol 11 (1) ◽  
pp. 120
Author(s):  
Linh Vu ◽  
Yun Suk Kang

In Korea, a precast floating track with anti-vibration isolators was recently developed to reduce the vibration and noise in urban railway stations, without disrupting train operations. This precast floating slab track is a newly developed structure and differs from existing conventional slab tracks. In this study, a Finite Element Method program (MIDAS CIVIL 2019) was used to analyze the load-carrying ability of structures under the train axle loads. After finishing the design, to understand more precisely about load transfer efficiency of this type of track, an assembly test (two load cases) was conducted with three precast panels (with rail 60 K mounted on) and compared with Finite Element Analysis results. The final results satisfied the test standards in Korea, which confirms that the precast floating track has an acceptable safety factor and structural behavior.


Author(s):  
Michael I. Hammons

A rational, three-dimensional (3D) finite element modeling technique was developed to predict the structural response of a jointed concrete airport pavement system. Model features include explicit 3D modeling of the slab continua, load transfer capability at the joint, explicit 3D modeling of the base course continua, load transfer capability across the cracks in the base course, and contact interaction between the slabs and base course. Environmental effects were not explicitly included in the model development. The model was applied to predict the response of an instrumented pavement at the Denver International Airport (DIA) to a test vehicle driven over the instrumented pavement under day and night conditions. The DIA pavement was modeled as a three-layer system with the presence of cracking in the base course as well as a variety of interface conditions between the slabs and base course considered. Complex response patterns caused by environmental factors were observed in the data from DIA, making separation of load-induced and environmentally induced response difficult. The general shape and form of the deflection- and stress-based load transfer efficiency predictions from the finite element models match those observed at DIA. Model predictions of stress-based load transfer efficiencies were generally more accurate than predictions of deflection-based load transfer efficiency. The model developed represents a significant advancement in the state of the art and features innovations that are compatible with the FAA’s advanced pavement design model requirements.


Author(s):  
Neeraj Buch ◽  
Dan G. Zollinger

The results of an in-depth study of factors that affect dowel looseness in jointed concrete pavements are presented. The laboratory investigation revealed the influence of aggregate type (in relation to oxide content), aggregate texture and shape, bearing stress (dowel diameter and crack width), load magnitude, and number of load cycles on the magnitude of dowel looseness and the subsequent loss in load transfer efficiency across saw-cut joints. A discussion is included on the development of an empirical-mechanistic dowel looseness prediction model based on the experimental results. Results of the sensitivity analysis of the dowel looseness prediction model (using laboratory data) are also presented. An associated scope of this research was to develop a relationship between dowel looseness and loss of load transfer efficiency. The sequential use of the dowel looseness prediction model and its relationship to load transfer efficiency allows the design engineer to predict load transfer characteristics of a joint, based on calculated (or measured) dowel looseness. The framework suggested to predict dowel looseness can then be incorporated into a fault prediction model for doweled joints.


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