scholarly journals Traffic Sensing Methodology Combining Influence Line Theory and Computer Vision Techniques for Girder Bridges

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xudong Jian ◽  
Ye Xia ◽  
Jose A. Lozano-Galant ◽  
Limin Sun
Keyword(s):  
Computer Vision ◽  
Safety Evaluation ◽  
Field Tests ◽  
Theoretical Background ◽  
Traffic Load ◽  
Systematic Analysis ◽  
Motion System ◽  
Influence Line ◽  
Line Theory ◽  
Girder Bridge

Collecting the information of traffic load, especially heavy trucks, is crucial for bridge statistical analysis, safety evaluation, and maintenance strategies. This paper presents a traffic sensing methodology that combines a deep learning based computer vision technique with the influence line theory. Theoretical background and derivations are introduced from both aspects of structural analysis and computer vision techniques. In addition, to evaluate the effectiveness and accuracy of the proposed traffic sensing method through field tests, a systematic analysis is performed on a continuous box-girder bridge. The obtained results show that the proposed method can automatically identify the vehicle load and speed with promising efficiency and accuracy and most importantly cost-effectiveness. All these features make the proposed methodology a desirable bridge weigh-in-motion system, especially for bridges already equipped with structural health monitoring system.

Multi-Vehicle Load Identification Using Existing Bridge Health Monitoring System

2019 ◽  
Author(s):  
Limu Chen ◽  
Xudong Jian ◽  
Ye Xia ◽  
Limin Sun
Keyword(s):  
Computer Vision ◽  
Monitoring System ◽  
Health Monitoring ◽  
Safety Evaluation ◽  
Field Tests ◽  
Theoretical Background ◽  
Traffic Load ◽  
Systematic Analysis ◽  
Health Monitoring System ◽  
Vehicle Load

<p>Collecting the information of traffic load, especially heavy trucks, is crucial for bridge statistical analysis, safety evaluation, as well as maintenance strategies. This paper presents a traffic sensing methodology that combines a deep learning based computer vision technique with the influence line theory. Theoretical background and derivations are introduced from both aspects of structural analysis and computer vision techniques. In addition, to evaluate the effectiveness and accuracy of the proposed traffic sensing method through field tests, a systematic analysis is performed on a continuous box-girder bridge. The obtained results show that the proposed method can automatically identify the vehicle load and speed with promising efficiency and accuracy, and most importantly cost-effectiveness. All these features make the proposed methodology a desirable bridge weigh-in-motion system, especially for bridges already equipped with structural health monitoring system.</p>

scholarly journals Comparision of constant-span and influence line methods for long-span bridge load calculations

2016 ◽  
Vol 11 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Ainars Paeglitis ◽  
Andris Freimanis
Keyword(s):  
Measurement Errors ◽  
Gumbel Distribution ◽  
Traffic Load ◽  
Design Stage ◽  
Long Span Bridges ◽  
Load Models ◽  
Long Span ◽  
Motion System ◽  
Influence Line ◽  
Long Span Bridge

Traffic load models available in building standards are most often developed for short or medium span bridges, however, it is necessary to develop traffic load models just for long span bridges, because the most unfavourable traffic situations are different. Weigh-in-Motion system data from highway A1 and A3 were used in this study. Measurement errors from data were cleaned using two groups of filters. The first group was based on vehicle validity codes recorded by both systems, if any circumstances might have influenced the measurements, the second group cleaned data using general filters for all vehicles and specific filters for trucks and cars. Additionally, vehicles were adjusted for influence of temperature. Data cleaning increased the average gross vehicle, so it could be considered as a conservative choice. Six traffic scenarios, each with different percentage of cars in the traffic, were made to assess the difference in loads from different traffic compositions. Traffic loads for long-span bridges were calculated using two approaches: the first assuming constant span length, the second, using influence lines from a bridge currently in design stage. Gumbel distribution were fitted to the calculate loads and they were extrapolated to probability of exceedance of 5% in 50 year period. Results show that influence line approach yield larger loads than those from constant-span. Both approaches result in loads larger than ones in Eurocode 1 Load Model 1, however, increase might have been caused by an increase in vehicle weight.

scholarly journals Infrastructure Safety Oriented Traffic Load Monitoring Using Multi-Sensor and Single Camera for Short and Medium Span Bridges

2019 ◽  
Vol 11 (22) ◽  
pp. 2651 ◽  
Author(s):  
Ye Xia ◽  
Xudong Jian ◽  
Bin Yan ◽  
Dan Su
Keyword(s):  
Field Tests ◽  
Traffic Monitoring ◽  
Strain Sensors ◽  
Traffic Load ◽  
Test Results ◽  
Moving Vehicles ◽  
Load Monitoring ◽  
Single Sensor ◽  
Girder Bridge ◽  
The Cost

A reliable and accurate monitoring of traffic load is of significance for the operational management and safety assessment of bridges. Traditional weight-in-motion techniques are capable of identifying moving vehicles with satisfactory accuracy and stability, whereas the cost and construction induced issues are inevitable. A recently proposed traffic sensing methodology, combining computer vision techniques and traditional strain based instrumentation, achieves obvious overall improvement for simple traffic scenarios with less passing vehicles, but are enfaced with obstacles in complicated traffic scenarios. Therefore, a traffic monitoring methodology is proposed in this paper with extra focus on complicated traffic scenarios. Rather than a single sensor, a network of strain sensors of a pre-installed bridge structural health monitoring system is used to collect redundant information and hence improve accuracy of identification results. Field tests were performed on a concrete box-girder bridge to investigate the reliability and accuracy of the method in practice. Key parameters such as vehicle weight, velocity, quantity, type and trajectory are effectively identified according to the test results, in spite of the presence of one-by-one and side-by-side vehicles. The proposed methodology is infrastructure safety oriented and preferable for traffic load monitoring of short and medium span bridges with respect to accuracy and cost-effectiveness.

Steel Girder Bridge with RC Deck Retrofit From Non-Composite to Composite Behaviour

2016 ◽  
Author(s):  
Abheetha Peiris ◽  
Issam Elias Harik
Keyword(s):  
Field Tests ◽  
High Strength ◽  
The United States ◽  
Field Application ◽  
Steel Girder ◽  
Shear Connectors ◽  
Before And After ◽  
Steel Girder Bridge ◽  
Girder Bridge ◽  
Concrete Deck

In the past, a number of steel girder-reinforced concrete deck bridges on county roads in the United States have been built as non-composite. Most of these bridges currently have load postings limiting the capacity of bus and truck loads on their roadways. Recent research showed that post installed high strength bolts could be used as shear connectors in rehabilitation work to achieve partial composite design by deploying 30% to 50% of the connectors typically required for a full composite design. This paper presents details on the analysis, design, and field application of post-installed shear connectors on a non-composite concrete deck steel girder bridge in Kentucky. In order to minimize traffic disruption and construction costs, the shear connectors were inserted on the bottom side of the deck through the top flange of the steel girder. While the load rating increased by 132%, field tests conducted before and after installation of the shear connectors showed that the bridge's live load deflections were reduced by more than 27%.

scholarly journals Comparison of Real Response and Theoretical Modeling of Pavement with Thick Asphalt Layers under Heavy Traffic Load

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Jingsong Shan ◽  
Hongmei Shao ◽  
Qiuzhong Li ◽  
Peili Sun
Keyword(s):  
Theoretical Model ◽  
Heavy Traffic ◽  
Field Tests ◽  
Fatigue Cracking ◽  
Field Measurements ◽  
Traffic Load ◽  
Theoretic Model ◽  
Static Modulus ◽  
Two Samples ◽  
The Difference

Two kinds of asphalt pavement with thick asphalt layers were used to construct two samples. In structure I, a semirigid base and graded crushed stone subbase were used. In structure II, a granular base and semirigid subbase layer were used. Responses of the two structures under traffic loads were measured using optical fiber sensors, and the differences between theoretical model results and field measurements were analyzed. Field measurements show that vertical compressive stress in structure I is larger than that in structure II. The maximum tensile strain of the asphalt layer is located at the bottom of the AC-25C layer in structure I and at the bottom of the AC-25F layer in structure II. The latter is significantly larger than the former, indicating the possibility of fatigue cracking induced by traffic load is higher in structure II. The measured tensile horizontal strain at the bottom of the semirigid layer is relatively low (<30εμ) in both structure I and structure II. In theoretical model, static modulus, dynamic modulus, and interface bonding ability are considered and theoretical responses are calculated. There are significant differences between the theoretical results and field test data. In the theoretic model, the material properties of layers and bonding status of adjacent layers all influence the results. In order to reduce the difference between the calculated and measured results, numerous material tests and field tests should be carried out.

scholarly journals Technologies, Discourse Analysis, and the Spoken Word: The MRC Approach: An Empirical Approach to Interpreter Performance Evaluation and Pedagogy

2009 ◽  
Vol 50 (4) ◽  
Author(s):  
Peter P. Lindquist
Keyword(s):  
Performance Evaluation ◽  
Empirical Evidence ◽  
Cognitive Processes ◽  
Theoretical Work ◽  
Training Needs ◽  
Theoretical Background ◽  
Spoken Word ◽  
Systematic Analysis ◽  
Recent Developments

Abstract Given the evanescent quality of the spoken word, interpreters tend to be evaluated, trained, and selected on the basis of unproven theories and preconceptions about the cognitive processes and areas of difficulty associated with their work. A gap persists between theoretical work and empirical evidence of the processes proposed by such studies. Recent developments in technology are now being applied to interpreter performance evaluation, shedding light on aspects of interpreter performance that have previously resisted systematic analysis. It is now possible to examine large volumes of language in use, in both audio and textual realms. This paper presents the MRC model for analysis of interpreter performance and a study conducted using that method for the purpose of identifying interpreter training needs. Theoretical background, the MRC model, and the study outcomes and pedagogical implications are presented.

Revisiting arching in deck slabs

1996 ◽  
Vol 23 (4) ◽  
pp. 973-981 ◽  
Author(s):  
Baidar Bakht
Keyword(s):  
Design Method ◽  
Field Tests ◽  
Scale Model ◽  
Girder Bridges ◽  
Transverse Arch ◽  
Deck Slabs ◽  
Arching Action ◽  
Girder Bridge ◽  
Concrete Deck ◽  
Deck Slab

The arching action in concrete deck slabs of girder bridges is generally recognized and is utilized by the Ontario Highway Bridge Design Code, and some other codes, to specify an empirical design method which leads to considerable savings in the amount of reinforcement. Despite this general recognition, there are some aspects of the arching action that are yet to be explored. To the knowledge of the author, all reported laboratory and field tests on deck slabs exploring its arching action under applied loads have been conducted by measuring strains in the bottom transverse reinforcement midway between the girders. Based on the results of tests on a full-scale model of a deck slab, it has been confirmed in this note that the transverse bottom reinforcement in the deck slab acts as a tie to the internal transverse arch in the slab. Because of embedment in concrete, the force in this reinforcement is the smallest midway between the girders, and not the largest as would be the case if the slab were in pure bending. Key words: arching in slabs, deck slabs, girder bridge, punching shear, steel-free deck slabs.

scholarly journals A Simplified Shear-Strain Based Bridge Weigh-In-Motion Method For In-Service Highway Bridges

2019 ◽  
Vol 8 ◽  
pp. 11-22
Author(s):  
Sergio Lobo Aguilar ◽  
Richard E. Christenson
Keyword(s):  
Shear Strain ◽  
Field Tests ◽  
Highway Bridges ◽  
Influence Line ◽  
Bending Strain ◽  
Weigh In Motion ◽  
Gross Vehicle Weight ◽  
Bridge Weigh In Motion ◽  
The Difference ◽  
Motion Method

Bridge Weigh-In-Motion (BWIM) has been demonstrated to be reliable for obtaining critical information about the characteristics of trucks that travel over the highways. Continued improvements provides greater opportunity for increased use of BWIM. Traditional BWIM systems based on measuring the bending strain of the bridge have various challenges which has led to a class of BWIM methodologies that employ the use of shear strain in determining the gross vehicle weight (GVW) of crossing trucks. However, the known techniques of these shear-strain BWIM methods assume or measure the shear influence line for the calculation of the GVW. In this paper, an alternative shear-strain based BWIM technique is proposed. The method presented here is independent of the influence line, does not require a measurement of the speed of the truck, and is based on the difference in magnitude observed at the discontinuity of the shear strain record as a truck crosses over the sensor location on the bridge. A series of field tests is presented that demonstrate this shear-strain based BWIM method has error levels consistent with other more complex BWIM methods and as such has great potential to be used for determining the GVWs of trucks that travel on simple or multispan bridges in a consistent and reliable manner.

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