Safe Platooning Headways on Girder Bridges

2021 ◽  
pp. 036119812110363
Author(s):  
Bowen Yang ◽  
Joshua S. Steelman ◽  
Jay A. Puckett ◽  
Daniel G. Linzell
Keyword(s):  
Prestressed Concrete ◽  
Limit State ◽  
Live Load ◽  
Load Effect ◽  
Operational Strategies ◽  
Reliability Indices ◽  
Girder Bridges ◽  
Legal Limits ◽  
Weigh In Motion ◽  
Load And Resistance Factor

Truck platooning—digitally linking two or more trucks to travel in a closely spaced convoy—is an emerging technology with the potential to save fuel and reduce labor. A framework is described to determine how much a platoon permit load might be increased above Federal Bridge Formula B legal limits, given strict control over the load characteristics and operational tactics. Soon, platoons are expected to advance not only with respect to traffic operations but also in their ability to weigh and report axle weight and spacing, functioning as mobile weigh-in-motion vehicles. Consequently, platoon live load statistics (bias and coefficient of variation) can differ from code assumptions, and are perhaps controllable, which poses a significant opportunity with respect to operational strategies. A parametric study is presented that examined safe headways between platooning trucks, considering different girder spacings, span lengths, numbers of spans, types of structure, truck configurations, numbers of trucks, and adjacent lane loading scenarios. The Strength I limit state was evaluated for steel and prestressed concrete I-girder bridges optimally designed using load and resistance factor design. Reliability indices, β, were calculated for each load case based on Monte Carlo simulation. Summary headway guidance was developed and is presented here to illustrate potential safe operational strategies for varying truck weights and platoon live load effect uncertainties.

Load Rating of Prestressed Concrete Girder Bridges

2005 ◽  
Vol 1928 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Brandy J. Rogers ◽  
David V. Jáuregui
Keyword(s):  
New Mexico ◽  
Prestressed Concrete ◽  
Resistance Factor ◽  
Live Load ◽  
Dead Load ◽  
Girder Bridges ◽  
Load Effects ◽  
The Dead ◽  
Load And Resistance Factor ◽  
Concrete Girder

In light of the adoption of the load and resistance factor design (LRFD) philosophy by the AASHTO Subcommittee on Bridges and Structures, research efforts are under way to facilitate the transition from load factor rating (LFR) to load and resistance factor rating (LRFR) in New Mexico. Five prestressed concrete girder bridges, courtesy of the New Mexico bridge inventory, were rated with the BRASS-GIRDER and BRASS-GIRDER (LRFD) structural software. The objectives for this study were to evaluate and verify the BRASS (bridge rating and analysis of structural systems) software, to identify the source of dissension between LFR and LRFR rating factors, and to examine any trends in the rating factors as affected by bridge geometry. The comparison of LFR and LRFR focused on both flexure and shear for the strength limit state. The LRFR method generally yielded lower rating factors for flexure, with the longer-span bridges demonstrating a larger deviation between LFR and LRFR. The live load effects were identified as the major factor contributing to the difference in flexure ratings; the dead load effects and flexural resistance had little effect. The LRFR rating factors for shear also were generally lower than those produced by LFR. The discrepancy in the shear ratings was caused by both the live load effects and shear resistance. The dead load effects contributed little to the variation in LFR and LRFR rating factors for shear. Overall, the shear ratings controlled over those based on flexure.

Live-Load Girder Distribution Factors for Bridges Subjected to Wide Trucks

2000 ◽  
Vol 1696 (1) ◽  
pp. 144-149 ◽  
Author(s):  
Sami W. Tabsh ◽  
Muna Tabatabai
Keyword(s):  
Finite Element ◽  
The United States ◽  
Live Load ◽  
Wheel Load ◽  
Element Analysis ◽  
Load Effect ◽  
Design Specifications ◽  
Girder Bridges ◽  
Girder Distribution Factors ◽  
Modification Factor

An important problem facing engineers and officials in the United States is the constraint imposed on transportation due to limitations of bridges. These limitations typically constrain vehicles to minimum heights and widths, to minimum and maximum lengths, and to a maximum allowable weight. However, with current demands of society and industry, there are times when a truck must carry a load that exceeds the size and weight of the legal limit. In this situation, the trucking company requests from the state departments of transportation an overload permit. For a truck with a wheel gauge larger than 1.8 m (6 ft), the process of issuing a permit for an overload truck requires a tremendous amount of engineering efforts. This is because the wheel load girder distribution factors (GDFs) in the design specifications cannot be used to estimate the live-load effect in the girders. In some cases, an expensive and time-consuming finite element analysis may be needed to check the safety of the structure. In this study, the finite element method is used to develop a modification factor for the GDF in AASHTO’s LRFD Bridge Design Specifications to account for oversized trucks with a wheel gauge larger than 1.8 m. To develop this factor, nine bridges were considered with various numbers of girders, span lengths, girder spacings, and deck slab thicknesses. The results indicated that use of the proposed modification factor with the GDF in the design specifications can help increase the allowable load on slab-on-girder bridges.

Prestressed Concrete Continuous Beam Bridge Span Arrangement and Structure Size Proposed Analytical

2014 ◽  
Vol 496-500 ◽  
pp. 2516-2519
Author(s):  
Chun Hui Dong
Keyword(s):  
Prestressed Concrete ◽  
Limit State ◽  
Steel Beam ◽  
Live Load ◽  
Cross Sectional ◽  
Bridge Span ◽  
Continuous Beam Bridge ◽  
Stress And Deformation ◽  
Beam Bridge

By analyzing the bridge structure in the course of the dead load and live load, taking into account different load safety factor for load combinations that will limit state as a result of the combination of two kinds of forces calculated tendon force estimates, estimate the various sections of the steel beam, in accordance with certain requirements of the steel beam is a good layout, construction and consider re-simulate prestress for the role of the second combination, the process of the construction and use of a cross-sectional strength checking, stress and deformation checking checking.

Calibration of the Ontario Highway Bridge Design Code 1991 edition

1994 ◽  
Vol 21 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Andrzej S. Nowak ◽  
Hid N. Grouni
Keyword(s):  
Reinforced Concrete ◽  
Reliability Analysis ◽  
Prestressed Concrete ◽  
Highway Bridge ◽  
Live Load ◽  
Design Code ◽  
Reliability Indices ◽  
Resistance Factors ◽  
Load And Resistance Factors ◽  
Selection Of

The paper describes the calculation of load and resistance factors for the Ontario Highway Bridge Design Code (OHBDC) 1991 edition. The work involved the development of load and resistance models, the selection of the reliability analysis method, and the calculation of the reliability indices. The statistical models for load and resistance are reviewed. The considered load components include dead load, live load, and dynamic load. Resistance models are developed for girder bridges (steel, reinforced concrete, and prestressed concrete). A reliability analysis is performed for selected representative structures. Reliability indices are calculated using an iterative procedure. The calculations are performed for bridge girders designed using OHBDC 1983 edition. The resulting reliability indices are between 3 and 4 for steel girders and reinforced concrete T-beams, and between 3.5 and 5 for prestressed concrete girders. Lower values are observed for shorter spans (up to 30–40 m). The acceptance criterion in the selection of load and resistance factors is closeness to the target reliability level. The analysis confirmed the need to increase the design live load for shorter spans. Partial resistance factors are considered for steel and concrete. The criteria for the evaluation of existing bridges are based on the reliability analysis and economic considerations. Key words: bridge code, calibration, load factor, resistance factor, reliability index.

Live Load Distribution in Prestressed Concrete Girder Bridges with Curved Slab

2013 ◽  
Vol 284-287 ◽  
pp. 1441-1445
Author(s):  
Doo Yong Cho ◽  
Sun Kyu Park ◽  
Woo Seok Kim
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Parametric Study ◽  
Load Distribution ◽  
Critical Parameters ◽  
Live Load ◽  
Finite Element Analyses ◽  
Distribution Factor ◽  
Girder Bridges ◽  
Live Load Distribution

This paper presents the live load distribution in straight prestressed concrete (PSC) girder bridges with curved deck slab utilizing finite element analyses. Numerical modeling methodology was established and calibrated based on field testing results. A parametric study of 73 cases with varying 6 critical parameters was used to determine a trend over each parameter. Through live load girder distribution factor (GDF) comparisons between the AASHTO LRFD, AASHTO Standard factors and finite element analyses results, both AASHTO live load distribution predicted conservatively in most bridges considered in the parametric study. However, in the bridges with curved slab, GDF was underestimated due to curvature influences. This study proposes a new live load distribution formula to predict rational and conservative live load distribution in PSC girder bridges with curved slab for a preliminary design purpose. The proposed live load distribution provides better live load analysis for the PSC girder bridge with curved slab and ensures the GDF is not underestimated.

Load effects of overweight and oversize vehicle traffic on pavements and bridges

2021 ◽  
Author(s):  
Eui-seung Hwang ◽  
Min-Tae Hwang ◽  
Do-Young Kim ◽  
Seong-Min Kim
Keyword(s):  
Concrete Pavements ◽  
Cement Concrete ◽  
Steel Girder ◽  
Load Effect ◽  
Vehicle Traffic ◽  
Girder Bridges ◽  
Weigh In Motion ◽  
Steel Girder Bridges ◽  
Load Effects ◽  
The Military

<p>Currently vehicle traffic regulations regarding on axle and total weights in Korea are simple, outdated and different from the regulations in other countries, such as US or European countries. In this study, load effect of over-loaded and special permit vehicle traffic on bridges and pavements are analyzed. Types of typical bridges include concrete and steel girder bridges. Types of pavements include asphalt and cement concrete pavements. Various weigh-in-motion (WIM) truck data are collected and used for comparing overweight ratios. Based on WIM truck data, load effects of various oversize vehicles mixed with common traffic are analyzed for various bridge types. Oversize vehicles include vehicles used in construction field, crane vehicles and transport vehicles for the military purpose. The effect of axle types on pavement design is also analyzed. The results of this study will be the basis of new provisions and regulations regarding on axle and total weights limitations as well as special permit vehicle.</p>

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