Probabilistic assessment of live load effects on continuous span bridges with regular and irregular configurations and its design implications

2020 ◽  
Vol 47 (4) ◽  
pp. 405-417
Author(s):  
A.D. García-Soto ◽  
A. Hernández-Martínez ◽  
J.G. Valdés-Vázquez
Keyword(s):  
Probabilistic Assessment ◽  
Live Load ◽  
Load Model ◽  
Motion Data ◽  
Load Models ◽  
Weigh In Motion ◽  
Single Vehicle ◽  
Load Effects ◽  
Extreme Distribution ◽  
Live Load Model

Studies on live load effects reported in recent literature are based on simple span bridges or on a limited number of continuous span bridges and regular configurations. In this study, an extensive probabilistic assessment of live load effects on continuous bridges is carried out for regular and irregular span configurations using weigh-in-motion data. Single vehicle passage is considered, and live load effects are compared with those from a live load model developed for simple spans from the same database. Truck models from Canada are also used for comparison purposes. Discussion of the fitting of extreme distribution is included, and an optimization scheme for the fitting is proposed. The most important finding of the study is that the use of live load models developed from simple spans or a limited number of continuous spans may not be suitable for designing continuous bridges, especially those with irregular configurations and short spans.

Statistical Investigation of Design Live Load by Applying WIM Data with Different Degree of Compliance with Truck Weight Limit

2018 ◽  
Author(s):  
Inyeol Paik ◽  
Kilhwan Jeong
Keyword(s):  
Measurement Data ◽  
Statistical Investigation ◽  
Live Load ◽  
Overload Control ◽  
Safety Level ◽  
Motion Data ◽  
Weigh In Motion ◽  
Single Vehicle ◽  
Live Load Model ◽  
Truck Weight

<p>The live load model applied to the design of the bridge should be defined so that a target safety level can be secured in the actual traffic environment. In this paper, it is presented that the live load could be greatly affected by the measurement data used for the statistical estimation process. For this purpose, a statistical analysis is performed on WIM (weigh-in-motion) data measured during different periods in terms of the overload control at the same spot of an expressway in Korea. The effects by a single vehicle, the back-to-back series vehicles and the side-by-side parallel vehicles are obtained and compared.</p>

scholarly journals Single and multiple presence statistics for bridge live load based on weigh-in-motion data

2017 ◽  
Vol 10 (6) ◽  
pp. 1163-1173 ◽  
Author(s):  
E. L. PORTELA ◽  
R. M. TEIXEIRA ◽  
T. N. BITTENCOURT ◽  
H. NASSIF
Keyword(s):  
High Speed ◽  
Daily Basis ◽  
Concrete Bridges ◽  
General Tendency ◽  
Live Load ◽  
Motion Data ◽  
Load Models ◽  
Weigh In Motion ◽  
Live Load Model ◽  
Bridge Spans

Abstract Modeling the traffic loads on bridges has been the subject of numerous studies. Defining a live load model to be used for bridge design is not an easy task. It demands among many other things a reliable dataset, a well-defined procedure for filtering data and also the determination of statistics for single and multiple presence occurrences. This study examines and characterizes the live load statistics for Brazilian concrete bridges. Single and multiple truck presence are evaluated for different bridge spans and truck daily volume. The sample is comprised of the thirteen months of data from a High Speed Weigh-In-Motion station (HS-WIM) in a resolution of one hundredth of a second currently operating on the Fernão Dias highway, also known as BR-381. The system provides eleven thousand records on a daily basis. After the filtering process three thousand trucks remain. The station takes measures in an same-direction two-lane highway, which allows the evaluation and characterization of both single and multiple presence statistics. Three case of multiple presence are considered: following, side-by-side and staggered cases. The consideration of truck multiple presence on concrete bridges is mandatory to understand and characterize live load models. The results show that with the exception of the side-by-side case, the frequency of multiple truck presence is significantly affected by span length. It also shows that the daily truck volume considerably affects the multiple presence statistics for all load patterns. The results show that the general tendency of the occurrence of all multiple presence events is to increase as the truck volume increases.

Reliability-Based Site-Specific Live Load Models for the Gordie Howe International Bridge

2019 ◽  
Author(s):  
Todd Ude ◽  
Y. Eddie He ◽  
Matt Chynoweth ◽  
Zaher Yousif
Keyword(s):  
Live Load ◽  
Simulation Studies ◽  
Traffic Patterns ◽  
Limit States ◽  
Site Specific ◽  
Motion Data ◽  
Load Models ◽  
Design Life ◽  
Weigh In Motion ◽  
Large Databases

<p>This paper discusses the development of project-specific live load models to achieve target reliability levels for the Gordie Howe International Bridge. This new bridge between Windsor, Ontario Canada and Detroit, Michigan USA will have a main span of 853 m (2800 ft), a design life of 125 years, and will experience atypical traffic patterns as a result of customs inspection plazas required at both ends of the bridge. Due to these variations relative to standard practice, large databases of weigh-in-motion data and simulation studies were used to modify the live load models of both country’s codes following the approach of NCHRP 683. The limit states addressed extend beyond the Strength 1 (ULS 1), to include high dead-to-live ratio combinations, and fatigue limit states.</p>

scholarly journals Development of Brazilian highway live load model for unlimited fatigue life

2020 ◽  
Vol 13 (4) ◽  
Author(s):  
Anselmo Leal Carneiro ◽  
Enson de Lima Portela ◽  
Túlio Nogueira Bittencourt
Keyword(s):  
Fatigue Life ◽  
Bending Moment ◽  
Highway Bridges ◽  
Live Load ◽  
Box Girders ◽  
Load Effect ◽  
Load Model ◽  
Weigh In Motion ◽  
Bias Factor ◽  
Live Load Model

Abstract This work studies the fatigue live load model used in Brazil for highway bridges. Using the unlimited fatigue life approach, the current live load model is evaluated in relation to the actual traffic and a new fatigue live load model is proposed. Weigh-in-motion (WIM) stations data on two important Brazilian highways are used. The main structural analysis performed in this paper consider the bridges as box girders or multiple girders. The ratio between real traffic and the live load model load effect (bias factor) are determined for single and continuous spans in terms of bending moment and shear force. It is found that the bias factor of the current live load can vary a lot and may not ensure unlimited fatigue life. The proposed model, on the other hand, presents more uniform bias factors and is in accordance with the unlimited fatigue life approach for the WIM data.

scholarly journals Towards actual brazilian traffic load models for short span highway bridges

2015 ◽  
Vol 8 (2) ◽  
pp. 124-139 ◽  
Author(s):  
C. E. Rossigali ◽  
M. S. Pfeil ◽  
R. C. Battista ◽  
L. V. Sagrilo
Keyword(s):  
Highway Bridges ◽  
Traffic Load ◽  
Live Load ◽  
Heavy Vehicles ◽  
Load Model ◽  
Load Models ◽  
Short Span ◽  
Live Load Model ◽  
Traffic Simulations ◽  
Gathering Data

New live load models for highway bridge design in Brazil are under development by assembling real traffic database, traffic simulations, analytical-numerical modeling of the dynamic interaction between vehicle and structure and statistical extrapolations. This paper presents and discusses the results obtained in the first stages of this work which includes the comparison between the static effects due to the actual traffic of heavy vehicles and those generated by the live load model given in the current national code NBR 7188. It is demonstrated that this live load model is not appropriate to represent the actual traffic effects and may be, in some cases, non-conservative. The present work deals with short span bridges for two lanes single carriageway under free flow traffic scenarios. The representative static effects in these bridges due to the actual traffic of heavy vehicles are obtained by extrapolating its probability density functions to a certain return period. To this purpose, a traffic database was constructed by gathering data from several weighing stations in Brazilian highways which was then applied to perform traffic simulations through a specially developed computational tool.

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