scholarly journals Load Distribution in Precast Wide-Flange CPCI Girder Bridges

2021 ◽  
Author(s):  
Magued W. Ibrahim
Keyword(s):  
Load Distribution ◽  
Design Method ◽  
Structural Response ◽  
Distribution Factor ◽  
Girder Bridges ◽  
Short Period ◽  
Load Distribution Factors ◽  
The Cost ◽  
Conventional Systems ◽  
Load Distribution Factor

As Ontario bridge infrastructure enters the era of maintenance, rehabilitation and replacement, prefabricated bridge systems will certainly have many advantages as compared to the conventional systems. Prefabricated systems can be quickly assembled and the traffic can be opened in a very short period of time, minimizing the lane closure time, reducing the cost and design time, and minimizing forming and labour work. The Canadian Highway Bridge Design Code specifies simplified design method for slab-on-girder bridges in the form of moment and shear distribution factors. This thesis presents a parametric study, using the finite-element method, on a series of precast Wide-Flange CPCI girder bridges to examine the applicability of the CHBDC load distribution factors to this prefabricated bridge system. The parameters considered in this study include span length, number of lanes, number of girders, live load conditions, presence of intermediate diaphragms, and type of connections between individual girders. This study revealed that CHBDC load distribution factors generally overestimate the structural response of such bridges. As a result, a refined set of load distribution factor equations were developed.

scholarly journals Load Distribution in Precast Wide-Flange CPCI Girder Bridges

2021 ◽  
Author(s):  
Magued W. Ibrahim
Keyword(s):  
Load Distribution ◽  
Design Method ◽  
Structural Response ◽  
Distribution Factor ◽  
Girder Bridges ◽  
Short Period ◽  
Load Distribution Factors ◽  
The Cost ◽  
Conventional Systems ◽  
Load Distribution Factor

As Ontario bridge infrastructure enters the era of maintenance, rehabilitation and replacement, prefabricated bridge systems will certainly have many advantages as compared to the conventional systems. Prefabricated systems can be quickly assembled and the traffic can be opened in a very short period of time, minimizing the lane closure time, reducing the cost and design time, and minimizing forming and labour work. The Canadian Highway Bridge Design Code specifies simplified design method for slab-on-girder bridges in the form of moment and shear distribution factors. This thesis presents a parametric study, using the finite-element method, on a series of precast Wide-Flange CPCI girder bridges to examine the applicability of the CHBDC load distribution factors to this prefabricated bridge system. The parameters considered in this study include span length, number of lanes, number of girders, live load conditions, presence of intermediate diaphragms, and type of connections between individual girders. This study revealed that CHBDC load distribution factors generally overestimate the structural response of such bridges. As a result, a refined set of load distribution factor equations were developed.

INFLUENCE OF SPAN LENGTH AND CROSSBEAM ON LOAD DISTRIBUTION FACTOR FOR GIRDER BRIDGES

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Hyo-Gyoung Kwak ◽  
Joungrae Kim
Keyword(s):  
Finite Element ◽  
Load Distribution ◽  
Span Length ◽  
Distribution Factor ◽  
Steel Girder ◽  
Girder Bridges ◽  
Load Distribution Factor ◽  
Exterior Girder ◽  
Grillage Method ◽  
Concrete Girder

Load distribution factor at concrete girder bridges and steel girder bridges are analyzed with finite element method to see effect of span length and cross beam to load distribution factor. Span lengths of analyzed bridge models are 30m, 40m, 50m and 60m. The number of intermediate cross beam is increased from one to until distance between cross beams becomes 5m. The finite element analysis results show that concrete girder and steel girder can use same load distribution factor and span length doesn’t affect to load distribution factor. Even though load distribution factor in interior girders is not influenced by cross beam, in exterior girders it is influenced by cross beam. Effect of cross beam in exterior girder is influenced by the number of lanes and distance from exterior girder to curb. Since design code introduces conservative load distribution factor, economically improved load distribution factor is proposed. The proposed load distribution factor includes cross beam effect with the number of lanes and distance from exterior girder to curb. The proposed equation is compared with AASHTO code and grillage method which is well-known method to calculate load distribution. The comparison results showed that the proposed equation is more efficient and useful than AASHTO and safer than the grillage method.

Applicabiliy of the simplified load distribution factor equation to PSC girder bridges

2005 ◽  
Vol 9 (4) ◽  
pp. 313-319 ◽  
Author(s):  
Wonseok Chung ◽  
Kitjapat Phuvoravan ◽  
Judy Liu ◽  
Elisa D. Sotelino
Keyword(s):  
Load Distribution ◽  
Distribution Factor ◽  
Girder Bridges ◽  
Load Distribution Factor ◽  
Factor Equation

Simplified Load Distribution for Vehicles with Nonstandard Axle Gauges

2000 ◽  
Vol 1696 (1) ◽  
pp. 158-170 ◽  
Author(s):  
Brian L. Goodrich ◽  
Jay A. Puckett
Keyword(s):  
Load Distribution ◽  
Live Load ◽  
Distribution Factor ◽  
Rigorous Results ◽  
Girder Bridges ◽  
Finite Strip Method ◽  
Simplified Method ◽  
Live Load Distribution Factors ◽  
Live Load Distribution ◽  
Load Distribution Factors

Several simplified methods have been developed to determine the live-load distribution factors for overweight vehicles on slab-on-girder bridges; however, these methods were developed for vehicles with standard axles. Many vehicles exist with nonstandard axle configurations, such as two-wheel axles that are wider than 6 ft (1.83 m) and four-wheel axles with wheels that are evenly or unevenly spaced. For these vehicles, a rigorous analysis is generally desired but is often deemed uneconomical. Therefore, a simplified method should be an asset to the bridge community and the trucking industry. A simplified method for determining live-load distribution factors for vehicles with nonstandard axle configurations is presented. Distribution factor formulas for moment and shear in interior and exterior girders are given. These formulas account for the transverse axle configurations that compose a vehicle. Several two- and four-wheel axle configurations are considered. The distribution factor formulas for slab-on-girder bridges presented in the AASHTO LRFD Bridge Design Specifications are incorporated into the proposed simplified method. The simplified method formulas were developed to approximate the results from a rigorous finite strip method. Comparisons are presented as verification of the accuracy of the simplified method. The simplified method results are usually conservative and correlate reasonably well with the rigorous results. In general, simplified methods worked better for interior girders than for exterior girders, and moment was better predicted than shear.

Evaluation of existing prestressed concrete bridges considering the randomness of live load distribution factor due to random vehicle loading position

2016 ◽  
Vol 20 (5) ◽  
pp. 737-746 ◽  
Author(s):  
Junyuan Yan ◽  
Lu Deng ◽  
Wei He
Keyword(s):  
Prestressed Concrete ◽  
Load Distribution ◽  
Random Variable ◽  
Live Load ◽  
Distribution Factor ◽  
Live Load Distribution ◽  
Load Distribution Factors ◽  
Bridge Assessment ◽  
Load Distribution Factor ◽  
Transverse Position

The live load distribution factor is a very important parameter in both the design of new bridges and the evaluation of in-service bridges. Studies have shown that there can be large discrepancy between the actual load distribution factors of field bridges and the load distribution factors predicted by bridge design codes. In addition, the load distribution factor is always treated as a constant in bridge assessment even though it is a random variable with certain statistical properties. In this study, the reliability indexes of 15 prestressed concrete girder bridges designed following the AASHTO LRFD code are calculated by considering the randomness of the load distribution factors induced by the random vehicle transverse position. It is found that there is a considerable increase in the calculated bridge reliability indexes, especially for short-span bridges, when the load distribution factor is modeled as a random variable with the statistical properties obtained from numerical simulations. This suggests that vehicle transverse position is one important factor that can be considered if a refined analysis is desirable when traditional evaluation methods predict unsatisfactory bridge assessment results. The findings in this article also highlight the importance of considering the actual vehicle transverse position in the evaluation of existing bridges.

scholarly journals Single-Lane Live Load Distribution Factor for Decked Precast, Prestressed Concrete Girder Bridges

2005 ◽  
Vol 1928 (1) ◽  
pp. 142-152 ◽  
Author(s):  
Jason L. Millam ◽  
Zhongguo (John) Ma
Keyword(s):  
Prestressed Concrete ◽  
Load Distribution ◽  
Live Load ◽  
Distribution Factor ◽  
Girder Bridges ◽  
Girder Bridge ◽  
Live Load Distribution ◽  
Load Distribution Factor ◽  
Precast Prestressed Concrete ◽  
Bridge System

The live load distribution factor equations provided by AASHTO load and resistance factor design specifications for the decked precast, prestressed concrete (DPPC) girder bridge system do not differentiate between a single-lane or a multilane loaded condition. This practice results in a single-lane load rating penalty for DPPC girder bridges. This paper determines distribution factor equations that accurately predict the distribution factor of the DPPC girder bridge system when it is subjected only to single-lane loading. Eight DPPC girder bridges were instrumented. Each bridge was loaded with a single load vehicle to simulate the single-lane loaded condition. The experimental data were used to calibrate grillage models of the DPPC girder bridge system. The calibrated grillage models were used to conduct a parametric study of the DPPC girder bridge system subjected to a single-lane loaded condition. Four new equations that describe the single-lane loaded distribution factor for both shear and moment forces of these bridges are developed in this paper.

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