Probability-Based Static Truck Loading Model for Rural Bridges in Saskatchewan

Author(s):  
Kien T. Doan ◽  
Lisa R. Feldman ◽  
Bruce F. Sparling

A study was conducted to establish a new truck load model intended for the evaluation and design of bridges with simple spans of 20m or less located on rural roads in Saskatchewan. Monte Carlo simulation was used to generate truck data sets based on site-specific traffic conditions determined from a traffic count program conducted between 2008 and 2012 across all 296 rural municipalities, and data collected from six weigh-in-motion stations in the province from January to December 2013. All axle weights and spacings were modelled as probabilistic parameters. The critical truck configuration featured a truck tractor with a steering axle and tandem axle group, and a truck trailer with a tridem axle group. Truck models with a common axle configuration but varying weights were developed for various reference periods that reliably reproduced extreme nominal load effects over those periods. The use of other data sets may lead to different results.

2020 ◽  
Vol 47 (4) ◽  
pp. 405-417
Author(s):  
A.D. García-Soto ◽  
A. Hernández-Martínez ◽  
J.G. Valdés-Vázquez

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.


2016 ◽  
Vol 11 (3) ◽  
pp. 197-204
Author(s):  
Zigang Xu ◽  
Qiang Han ◽  
Junfeng Jia ◽  
Zilan Zhong ◽  
Chao Huang

In order to assess the vehicle load carrying capacity of existing bridges on the national highway G103 in Beijing, the vehicle load model for the practical traffic flow conditions needs to be determined. Based on the traffic axle load data measured by the weigh-in-motion system and the methods proposed by General Code for Design of Highway Bridges and Culverts (JTG D60-2004) and Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts (JTG D62-2004), the vehicle load parameters under practical traffic flow conditions are investigated. A typical 6-axle vehicle model with a 2-1-3 axial pattern is proposed by using the statistical analysis of total weight, axial weight, etc. The live load effects of Daliushu No. 2 Bridge, one highway bridge on the national highway G103, are analyzed using the proposed model and compared to the vehicle load model given in the Chinese code. The results show that there are great differences in the vehicle load parameters and the live load effects from the proposed vehicle load model increased by 20–50% compared with the model given by the code. The overweight vehicles are potential threats to the safety of existing bridges.


2010 ◽  
Vol 2 (3) ◽  
pp. 60-66
Author(s):  
Nemunas Abukauskas ◽  
Egidijus Skrodenis

The results of lengthy thorough investigations into traffic safety situation show that the percentage of pedestrians getting involved in road traffic accidents on Lithuanian roads is significantly higher (more than 33 % of the total number of injury and fatal accidents) than that compared to the other European Union member-states. The article studies traffic safety problems and their factors causing the largest influence on the occurrence of these accidents. Considering valuable experience gained by foreign countries, investigation was carried out to establish general and main factors causing insufficient road safety conditions and significance of these factors to road safety. The article also shows the main activity improving road safety in Lithuania and discusses the effectiveness of strategic and local (temporary and long term) measures to improve conditions for pedestrian road safety.


Author(s):  
Nicolas Rodrigue ◽  
Thibault Latrille ◽  
Nicolas Lartillot

Abstract In recent years, codon substitution models based on the mutation–selection principle have been extended for the purpose of detecting signatures of adaptive evolution in protein-coding genes. However, the approaches used to date have either focused on detecting global signals of adaptive regimes—across the entire gene—or on contexts where experimentally derived, site-specific amino acid fitness profiles are available. Here, we present a Bayesian site-heterogeneous mutation–selection framework for site-specific detection of adaptive substitution regimes given a protein-coding DNA alignment. We offer implementations, briefly present simulation results, and apply the approach on a few real data sets. Our analyses suggest that the new approach shows greater sensitivity than traditional methods. However, more study is required to assess the impact of potential model violations on the method, and gain a greater empirical sense its behavior on a broader range of real data sets. We propose an outline of such a research program.


BMJ Open ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. e037719
Author(s):  
Helen Strongman ◽  
Rachael Williams ◽  
Krishnan Bhaskaran

ObjectivesTo describe the benefits and limitations of using individual and combinations of linked English electronic health data to identify incident cancers.Design and settingOur descriptive study uses linked English Clinical Practice Research Datalink primary care; cancer registration; hospitalisation and death registration data.Participants and measuresWe implemented case definitions to identify first site-specific cancers at the 20 most common sites, based on the first ever cancer diagnosis recorded in each individual or commonly used combination of data sources between 2000 and 2014. We calculated positive predictive values and sensitivities of each definition, compared with a gold standard algorithm that used information from all linked data sets to identify first cancers. We described completeness of grade and stage information in the cancer registration data set.Results165 953 gold standard cancers were identified. Positive predictive values of all case definitions were ≥80% and ≥94% for the four most common cancers (breast, lung, colorectal and prostate). Sensitivity for case definitions that used cancer registration alone or in combination was ≥92% for the four most common cancers and ≥80% across all cancer sites except bladder cancer (65% using cancer registration alone). For case definitions using linked primary care, hospitalisation and death registration data, sensitivity was ≥89% for the four most common cancers, and ≥80% for all cancer sites except kidney (69%), oral cavity (76%) and ovarian cancer (78%). When primary care or hospitalisation data were used alone, sensitivities were generally lower and diagnosis dates were delayed. Completeness of staging data in cancer registration data was high from 2012 (minimum 76.0% in 2012 and 86.4% in 2014 for the four most common cancers).ConclusionsAscertainment of incident cancers was good when using cancer registration data alone or in combination with other data sets, and for the majority of cancers when using a combination of primary care, hospitalisation and death registration data.


2018 ◽  
Vol 23 (11) ◽  
pp. 04018048 ◽  
Author(s):  
Nicholas R. Grieco ◽  
Jeffrey D. Niemann ◽  
Timothy R. Green ◽  
Andrew S. Jones ◽  
Peter J. Grazaitis

1999 ◽  
Vol 26 (5) ◽  
pp. 655-666 ◽  
Author(s):  
Xun Zhi ◽  
Ahmed Shalaby ◽  
Dan Middleton ◽  
Alan Clayton

The primary objective of a weigh-in-motion (WIM) system is to provide highway designers and agencies with information on the loads and traffic volumes using a particular highway, thereby facilitating improved pavement design, management, and weight enforcement. In this paper, the historic performance of WIM systems in Manitoba is evaluated. The results indicate that large numbers of unreasonable data are produced from the WIM systems, calibration procedures are not standardized, and there is drift in calibration. The performance of the Brokenhead WIM system was evaluated through a detailed survey conducted at the Brokenhead WIM site and the Westhawk Permanent Truck Weigh Station in August 1997. The Brokenhead site is on the Trans-Canada highway east of Winnipeg. It is the only WIM system in the country that measures truck characteristics and movements between eastern and western Canada. The survey produced a large database permitting the comparison of truck dimension measurements, truck weights, and vehicle classification between those produced by the WIM system and those observed manually. The results indicate that WIM axle-spacing data sets were outside the tolerance for 95% conformity specified by the American Society for Testing and Materials (ASTM). The system classified 5 to 9 axle combination trucks more accurately than some 2- and 3-axle vehicles. The WIM system underestimated about 90% of truck weights in the survey period. The degree of underestimation exceeded 50% of the corresponding static weights. This finding highlights the importance of quality control and corrections on WIM data prior to their use in research or engineering practice.Key words: weigh-in-motion, vehicle classification, calibration, axle spacing, axle load.


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