Live load factors for serviceability limit state of prestressed concrete girder stresses

2012 ◽  
pp. 3183-3190
Author(s):  
E Hwang ◽  
S Kim ◽  
S Nguyen
Keyword(s):  
Prestressed Concrete ◽  
Limit State ◽  
Live Load ◽  
Serviceability Limit State ◽  
Load Factors ◽  
Concrete Girder

Reliability Analysis of Prestressed Concrete Bridges in Mexico: Assessment and Live Load Factors Proposal

2021 ◽  
Author(s):  
Rolando Salgado-Estrada ◽  
Sergio A. Zamora-Castro ◽  
Agustín L. Herrera-May ◽  
Yessica A. Sánchez-Moreno ◽  
Yair S. Sánchez-Moreno
Keyword(s):  
Reliability Analysis ◽  
Prestressed Concrete ◽  
Concrete Bridges ◽  
Live Load ◽  
Prestressed Concrete Bridges ◽  
Load Factors

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.

Analysis of serviceability limit state of GFRP prestressed concrete beams

2015 ◽  
Vol 134 ◽  
pp. 450-459 ◽  
Author(s):  
Mantas Atutis ◽  
Juozas Valivonis ◽  
Edgaras Atutis
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Limit State ◽  
Serviceability Limit State

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.

Load and resistance factors for prestressed concrete girder bridges

2020 ◽  
Vol 19 (3) ◽  
pp. 103-115
Author(s):  
Andrzej S. Nowak ◽  
Olga Iatsko
Keyword(s):  
Prestressed Concrete ◽  
Theoretical Point ◽  
Design Point ◽  
Resistance Factors ◽  
Girder Bridges ◽  
Load Factors ◽  
Load And Resistance Factors ◽  
The Mean ◽  
Standard Deviations ◽  
Concrete Girder

There has been a considerable progress in the reliability-based code development procedures. The load and resistance factors in the AASHTO bridge design code were determined using the statistical parameters from the 1970's  and early 1980’s. Load and resistance factors were determined by first fixing the load factors and then calculating resistance factors. Load factors were selected so that the factored load corresponds to two standard deviations from the mean value and the resistance factors were calculated so that the reliability index is close to the target value. However, from the theoretical point of view, the load and resistance factors are to be determined as coordinates of the so-called “design point” that corresponds to less than two standard deviations from the mean. Therefore, the optimum load and resistance factors are about 10% lower than what is in the AASHTO LRFD Code. The objective of this paper is to revisit the original calibration and recalculate the load and resistance factors as coordinates of the “design point” for prestressed concrete girder bridges. The recommended new load and resistance factors provide a consistent reliability and a rational safety margin.

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.

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