Development of loading-truck model and live-load factor for the Canadian Standards Association CSA-S6 code

1987 ◽  
Vol 14 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Akhilesh C. Agarwal ◽  
Moe S. Cheung
Keyword(s):  
Highway Bridges ◽  
Load Level ◽  
Load Factor ◽  
Live Load ◽  
Limit States ◽  
Load Factors ◽  
Loading System ◽  
Using Data ◽  
Council Of Ministers ◽  
Level Loading

Studies have shown that the MS-200 loading model in the Canadian Standards Association standard CAN3-S6-M78 for design of highway bridges no longer represents modern-day heavy trucks in Canada. For the new edition of the CSA-S6 code, based on the limit states philosophy, a new loading-truck model was developed based on the Council of Ministers' loading, which is the legal load limit for interprovincial transportation in Canada. The loading model, designated as the "CS-W loading truck," provides the flexibility to adopt a multiple-level loading system appropriate to various jurisdictions.The live-load factor was determined from a statistical approach using data from a truck survey conducted across Canada in seven provinces. Responses in simple-span bridges were determined by running one or more trucks from the survey across the bridge. Based on this study, a live-load factor of 1.60 was determined and CS-600, with a gross weight of 600 kN, was selected as the standard load level. As well, the validity of the truck model and the live-load factors were checked for continuous-span bridges. Key words: highway bridges, design loads, codes and standards, live-load models, load factors, load surveys, vehicle weight regulations.

scholarly journals Calibration of the Live Load Factor for Highway Bridges with Different Requirements of Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Lang Liu ◽  
Qingyang Ren ◽  
Xu Wang
Keyword(s):  
Structural Reliability ◽  
Highway Bridges ◽  
Calibration Method ◽  
Mean Value ◽  
Load Factor ◽  
Live Load ◽  
Load Effect ◽  
Load Factors ◽  
Short Period ◽  
Traffic Volumes

Highway bridge load rating has been moving toward structural reliability since the issuance of AASHTO LRFR specifications; however, the recommended load factors were carried out by a few reliable truck data. The objective of this study is to calibrate the live load factor in AASHTO LRFR Rating Specification by using huge amount of WIM data collected in California for more than ten years between 2001 and 2013. Since traffic volumes, vehicular overloads, and traffic components are highly related to the load effect induced, a set of calibration equations is proposed here, in which the nominal standard load effect models are used and different requirements of loading are taken into account. By the analytical model of platoons of trucks and the extrapolation of the gathered WIM data over a short period of time to remote future over a longer time period, the expected maximum live load effects over the rating period of 5 years are also obtained. Then, the live load factor is calibrated as the product of the codified value multiplied by the ratio between the nominal standard load effect and the expected mean value. The results show that the products of the two ratios present rather constant, implying the proposed method and load configurations selected are effective. In the end, the live load factors of 1.0 and 0.7 along with load configurations are recommended for a simple span length less than 300 ft. The recommended calibration method and live load factors will eliminate the unnecessary overconservatism in rating specifications.

Load factor calibration for the proposed 2005 edition of the National Building Code of Canada: Companion-action load combinations

2003 ◽  
Vol 30 (2) ◽  
pp. 440-448 ◽  
Author(s):  
F M Bartlett ◽  
H P Hong ◽  
W Zhou
Keyword(s):  
Companion Paper ◽  
Building Code ◽  
Wind Loads ◽  
Load Factor ◽  
Live Load ◽  
Dead Load ◽  
Limit States ◽  
Snow Load ◽  
Load Factors ◽  
Snow Loads

The 2005 edition of the National Building Code of Canada (NBCC) will adopt a companion-action format for load combinations and specify wind and snow loads based on their 50 year return period values. This paper presents the calibration of these factors, based on statistics for dead load, live load due to use and occupancy, snow load, and wind load, which are summarized in a companion paper. A target reliability index of approximately 3 for a design life of 50 years was adopted for consistency with the 1995 NBCC. The load combinations and load factors for strength and stability checks recommended for the 2005 NBCC were based on preliminary values from reliability analysis that were subsequently revised slightly to address major inconsistencies with past practice. The recommended load combinations and factors generally give factored load effects similar to those in the 1995 NBCC, but are up to 10% more severe for the combination of dead load plus snow load and are generally less severe for the combination of dead load, snow load, and live load due to use and occupancy. Load factors less than one are recommended for checking serviceability limit states involving specified snow and wind loads. Importance factors for various classifications of structure are also presented. Revisions to the commentaries of the NBCC are recommended that will provide guidance on dead load allowances for architectural and mechanical superimposed dead loads and cast-in-place cover slabs and toppings.Key words: buildings, code calibration, companion action, dead loads, live loads, load combinations, load factors, reliability, safety, snow loads, wind loads.

Probabilistic assessment of a design truck model and live load factor from weigh-in-motion data for Mexican Highway bridge design

2015 ◽  
Vol 42 (11) ◽  
pp. 970-974 ◽  
Author(s):  
A.D. García-Soto ◽  
A. Hernández-Martínez ◽  
J.G. Valdés-Vázquez
Keyword(s):  
Bridge Engineering ◽  
Load Factor ◽  
Engineering Practice ◽  
Live Load ◽  
Bridge Design ◽  
Statistical Characterization ◽  
Motion Data ◽  
Weigh In Motion ◽  
Load Factors ◽  
Truck Load

This study is focused on the statistical characterization of live load effects on bridges using weigh-in-motion data from a Mexican highway. A truck load model that is simpler than the design truck model implemented in the current Mexican requirements is suggested for design. The statistics are employed in target-reliability based calibration and verification of load factors in Mexican bridge design. Suggestions that could be useful for the Canadian bridge engineering practice are included.

scholarly journals Force reduction factors for the seismic provisions of the National Building Code of Canada

1987 ◽  
Vol 14 (4) ◽  
pp. 447-454 ◽  
Author(s):  
J. H. Rainer
Keyword(s):  
Building Code ◽  
Load Factor ◽  
Limit States ◽  
Load Factors ◽  
Earthquake Resistant Structures ◽  
Structural Configurations ◽  
Force Reduction ◽  
Factor Α ◽  
Reduction Factors

A derivation of force reduction factors for the seismic provisions of the National Building Code of Canada (NBCC), 1985, is presented. This includes the following: classification of seismic actions, applicable limit states, change in load factor, derivation of force reduction factors, and classification of structural configurations. Quantitative comparisons are made between the derived force reduction factors and the response modification factors of the Applied Technology Council and good agreement was found. It is suggested that seismic requirements should be considered as accidental actions with a load factor αQ = 1.0. These results can form the basis for possible modifications to the 1985 NBCC seismic provisions. Key words: earthquake resistant structures, building code, loads, load factors.

scholarly journals Live Load Factors for Military Traffic in Bridge Evaluation

2020 ◽  
Author(s):  
Andrew James MacDonald ◽  
Mike Bartlett ◽  
Gordon R.G. Wight
Keyword(s):  
Highway Bridges ◽  
Live Load ◽  
Bridge Design ◽  
Traffic Loading ◽  
Girder Bridges ◽  
Military Vehicles ◽  
Code Calibration ◽  
Load Factors ◽  
Bridge Evaluation ◽  
Gross Vehicle Weight

Military vehicles are sometimes required to transit bridges owned and operated by civilian bridge authorities. Using available data regarding the gross vehicle weight and associated axle loads of military traffic, live load factors, calibrated to the Canadian Highway Bridge Design Code, are proposed for bridge design and evaluation. This paper recommends live load factors for three categories military vehicles: (1) Wheeled-Transport vehicles; (2) Wheeled-Fighting vehicles; and (3) Tracked-Fighting vehicles. The values are derived for interior girders of a simply supported slab-on-girder bridges subjected to a single lane of traffic loading and are believed to be generally applicable for other structural elements and bridge types. Inherent differences between fighting vehicles, which are heavily armoured, and transport vehicles, which although armoured have high payloads, suggest that highway bridges should be evaluated separately for military fighting vehicles and military transport vehicles using distinct live load factors. Keywords: Bridge Evaluation, Code Calibration, Military Vehicles.

Nonlinear analysis of cable-stayed bridges at ultimate load level

1996 ◽  
Vol 23 (5) ◽  
pp. 1111-1117 ◽  
Author(s):  
M. S. Khalil
Keyword(s):  
Ultimate Load ◽  
Load Level ◽  
Load Factor ◽  
Nonlinear Behaviour ◽  
Safety Index ◽  
Nonlinear Load ◽  
Cable Stayed Bridge ◽  
Load Factors ◽  
Analysis Design ◽  
Cable Stayed Bridges

Cable-stayed bridges have unique characteristics which require unique treatment in their analysis, design, and construction. This paper discusses some of these characteristics and presents proposed means of solving the associated problems. The paper discusses the nonlinear behaviour of the cable-stayed system, the load factors required for the analysis of that type of bridge, the manner of application of the loads, and the analysis under factored loads. The paper presents the results of the analysis of the ALRT cable-stayed bridge in Vancouver, Canada. Key words: cable-stayed, bridges, nonlinear, load factor, safety index.

scholarly journals Design Live-Load Factor Calibration for Michigan Highway Bridges

2016 ◽  
Vol 21 (6) ◽  
pp. 04016014 ◽  
Author(s):  
Christopher D. Eamon ◽  
Valid Kamjoo ◽  
Kazuhiko Shinki
Keyword(s):  
Highway Bridges ◽  
Load Factor ◽  
Live Load

scholarly journals Canadian highway bridge evaluation: load and resistance factors

1992 ◽  
Vol 19 (6) ◽  
pp. 992-1006 ◽  
Author(s):  
D. J. Laurie Kennedy ◽  
Darrel P. Gagnon ◽  
David E. Allen ◽  
James G. MacGregor
Keyword(s):  
Field Measurements ◽  
Highway Bridges ◽  
Live Load ◽  
Safety Criterion ◽  
Transverse Distribution ◽  
Resistance Factors ◽  
Load Factors ◽  
Target Values ◽  
Load And Resistance Factors ◽  
Live Loads

Consistent load and resistance factors are developed for a range of target values of the reliability index, β, following first-order second-moment analysis techniques for use in the evaluation of highway bridges. Dead load factors are established for steel girders, concrete girders, concrete bridge decks, and wearing surfaces, taking into account the statistical variations of weights and the range of load fractions as determined from field measurements. Live load factors are established for four categories of live loads: NP — non-permit traffic that are permitted by legislation; PM — permit, multiple trip, bulk haul, divisible loads; PS — permit, single trip, unsupervised, mixed with non-permit traffic; and PC — permit, controlled, supervised extremely heavy loads with escort. These live load factors are based on field surveys of truck weights, in Alberta and elsewhere. The event curves for NP, PS, and PM traffic have been used to determine the maximum annual truck, as the period of evaluation was chosen as 1 year based on a life-safety criterion-related to the consequences of failure. Because PC traffic is so rare, it was dealt with on an event basis. Impact data of others were analyzed to determine the appropriate bias coefficients and coefficients of variation. Uncertainties in the transverse distribution of both dead and live loads were also considered.Resistance factors are based on statistical data reported in the literature and take into account the variation in material properties, member size, and the resistance formulations. Key words: dead and live load factors, resistance factors, impact, maximum annual, traffic categories, transverse distribution, weight fractions.

Effect of guy initial tension on design of guyed antenna towers

1996 ◽  
Vol 23 (2) ◽  
pp. 457-463
Author(s):  
Yohanna M. F. Wahba ◽  
Murty K. S. Madugula ◽  
Gerard R. Monforton
Keyword(s):  
Load Factor ◽  
Case Scenario ◽  
Limit States ◽  
Initial Tension ◽  
Worst Case ◽  
Design Procedures ◽  
Design Engineers ◽  
Load Factors ◽  
Current Design ◽  
Guyed Towers

This study examines the effect of changing the initial guy tension on the design of guyed antenna towers. Six different guyed towers with various heights and loading conditions are used in this study, in which initial guy tensions are changed and the corresponding effect on the forces in the tower components are examined. Also, the methods used in measuring the initial tension are reviewed. On the basis of this study, it is proposed that the initial guy tensions have a load factor different from the value of 1.0 suggested in CSA S37-94. Two additional load combinations are developed from this analysis in order to assist design engineers in determining the worst case scenario for the variation of initial tension in the guys. Results are compared for designs using the current design procedures and the design using the proposed load factors for initial tensions in guy wires. Key words: antenna towers, guyed towers, limit states design, guys, initial tension.

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