scholarly journals Resistance Assessment of Service-Proven Aging Bridges Incorporating Deterioration-Load Dependency

2020 ◽  
Vol 5 (1) ◽  
pp. 10 ◽  
Author(s):  
Cao Wang
Keyword(s):  
Copula Function ◽  
Structural Resistance ◽  
Service Load ◽  
Prior Service ◽  
Structural Fragility ◽  
Deterioration Process ◽  
Loading Tests ◽  
Load Intensity ◽  
Beam Bridge ◽  
Bridge Resistance

The historical vehicles passed through an existing bridge can be regarded as proof-loading tests for the bridge, and, as a result, are evident of the bridge’s performance. Such service history information has been utilized to update the estimate of bridge resistance in previous studies with the help of a Bayesian method, where the resistance deterioration process was assumed to be independent of the vehicle load process. This assumption is, however, untenable in many cases where the deterioration stochastic process is statistically correlated with the load process (e.g., a greater load intensity may affect/accelerate the deterioration of structural resistance and the accumulation of structural fragility). With this regard, this paper investigates the effect of correlation between the resistance deterioration and load processes on updating the resistance of aging bridges with prior service load information. The copula function is employed to model the joint distribution of the correlated deterioration and load processes, with which the correlation is measured by the Kendall’s tau. A new method is developed in this paper to assess the updated bridge resistance taking into consideration the deterioration-load dependency in an explicit form. The applicability of the proposed method is illustrated using an existing RC beam bridge. The sensitivity analysis is conducted to examine how the deterioration-load dependency affects the updated resistance of service-proven aging bridges.

Simplified Method for Time-Dependent Reliability Analysis of Aging Bridges Subjected to Nonstationary Loads

2016 ◽  
Vol 23 (01) ◽  
pp. 1650003
Author(s):  
Cao Wang ◽  
Quanwang Li
Keyword(s):  
Structural Reliability ◽  
Operating Conditions ◽  
Time Dependent ◽  
Structural Resistance ◽  
Simplified Method ◽  
Increasing Trend ◽  
Live Loads ◽  
Load Intensity ◽  
Existing Bridges ◽  
Dimensional Integral

The performance of existing bridges may deteriorate in time due to aggressive environmental or operating conditions in service, which may eventually cause changes in structural resistance and reliability beyond the baseline assumed for new ones. In addition, the increasing trend of live loads applied to the bridges, which has been reported in many researches, also contributes to the reduction of structural reliability. In order to perform time-dependent reliability assessment for aging bridges subjected to nonstationary loading process with improved efficiency, a simplified method is proposed in this paper, where lower dimensional integral is involved in the calculation of reliability. With the proposed method, time-dependent reliability of a real aging RC bridge is conducted, and the effect of nonstationarity in load intensity on structural reliability is investigated. It is found that structural reliability is sensitive to the increase of load intensity, and is less sensitive to the varying mechanism of load intensity.

Proof testing of a noncomposite floor system

1979 ◽  
Vol 6 (4) ◽  
pp. 634-639
Author(s):  
Ram S. Ghosh
Keyword(s):  
Maximum Stress ◽  
Concrete Slab ◽  
Critical Section ◽  
Bridge Structure ◽  
System Construction ◽  
Strain Measurements ◽  
Proof Testing ◽  
Service Load ◽  
Beam Bridge ◽  
Floor System

A suspended concrete slab in a noncomposite floor system construction exhibited cracking in the upper surface, which was considered to be aggravated by the movement of heavy steel wheeled trolleys. A critical section of the floor was carefully instrumented for deflection and strain measurements and readings were taken with the heaviest service load at locations for maximum stress. The results established that the resulting induced stresses were relatively small, well below the allowable working values, which confirmed the prognosis that the complete floor was acting as an I-beam bridge structure. Accordingly, the floor was considered adequate to carry the 23.5 ton (21.3 Mg) moving trolley load.

scholarly journals Condition Evaluation of an Existing T-Beam Bridge Based on Neutral Axis Variation Monitored with Ultrasonic Coda Waves in a Network of Sensors

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3895 ◽  
Author(s):  
Hanyu Zhan ◽  
Hanwan Jiang ◽  
Jinquan Zhang ◽  
Ruinian Jiang
Keyword(s):  
Neutral Axis ◽  
Coda Waves ◽  
Strain Diagram ◽  
Structural Health ◽  
Novel Technique ◽  
Condition Evaluation ◽  
Loading Tests ◽  
Beam Bridge ◽  
T Beam ◽  
Axis Passing

Neutral axis passing through the stiffness centroid of a structure is correlated with structural health conditions. Traditional techniques rely on gauge arrays to observe strains at their installation positions, and then locate a neutral axis through the intercept of the strain diagram. However, these localization results will be severely deviated if any damages exist among gauges or inside structures. In this paper, a novel technique is proposed to locate the neutral axis by measuring and analyzing ultrasonic coda waves in a network of transducers. Because of multiple trajectories, coda waves are sensitive to minor changes in a large volume of media that are not limited to direct paths between sensors. This technique is not only capable of locating a neutral axis with great efficiency and accuracy, but can also indicate global structural health and inner damages. The applicability of the technique is demonstrated by monitoring a 30 m concrete T-beam subjected to four-point loading tests. With an array of transducers placed at the surface, the neutral axes in the large region are located. The localization results also show clear trends that the global neutral axis moves up as the loads increase, which indicates the beam contains certain degrees of inner damage.

Effect of cranial electro-stimulation on athletes’ recovery after practice of different load intensity

2015 ◽  
Vol 2 (80) ◽  
pp. 51-58
Author(s):  
Andris Rudzitis ◽  
Jame K. Daly ◽  
Viesturs Larins ◽  
Leonids Chupriks ◽  
Leonids Zhilinskis ◽  
...  
Keyword(s):  
Load Intensity

Support vector approach using data augmentation with copula function applied to load forecasting

2019 ◽  
Author(s):  
Gabriel Ribeiro ◽  
Marcos Yamasaki ◽  
Helon Vicente Hultmann Ayala ◽  
Leandro Coelho ◽  
Viviana Mariani
Keyword(s):  
Data Augmentation ◽  
Load Forecasting ◽  
Copula Function ◽  
Support Vector ◽  
Using Data ◽  
Vector Approach
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