Shear distribution in simply supported skew composite bridges

1995 ◽  
Vol 22 (6) ◽  
pp. 1143-1154 ◽  
Author(s):  
Tarek Ebeido ◽  
John B. Kennedy
Keyword(s):  
Parametric Study ◽  
Load Distribution ◽  
Experimental Program ◽  
Distribution Factor ◽  
Simply Supported ◽  
Shear Distribution ◽  
Truck Loading ◽  
Composite Bridges ◽  
Bridge Models ◽  
Composite Steel

Composite steel–concrete bridges remain one of the most common types built. Proper design of new bridges and evaluation of existing bridges requires accurate prediction of their structural response to truck loads. The American Association of State Highway and Transportation Officials has traditionally applied a load distribution factor for both moment and shear. The Ontario Highway Bridge Design Code (OHBDC) considers several parameters in establishing load distribution factors for moment. However, the method is limited to bridges with skew parameters less than a certain value specified in the code. The presence of skew reduces the longitudinal moments in the girders. However, it also causes high concentration of shear in the girder closest to the obtuse corner and reduces shear concentration in the girder closest to the acute corner as well as in the interior girders. Therefore, shear should be considered in the design of such bridges. In this paper, the influence of skew on the shear distribution factor is investigated. The influences of other factors such as girder spacing, bridge aspect ratio, number of lanes, number of girders, end diaphragms, and intermediate cross-beams are presented. An experimental program was conducted on six simply supported skew composite steel–concrete bridge models. Results from a finite element analysis showed excellent agreement with the experimental results. An extensive parametric study was conducted on prototype composite bridges subjected to OHBDC truck loading. The parametric study included more than 400 cases. The data generated were used to develop empirical formulas for shear distribution factors for OHBDC truck loading and also for dead load. An illustrative example is presented. Key words: bridges, codes of practice, composite, distribution, reaction, reinforced concrete, shear, skew, structural engineering, tests.

Load Distribution for Moment and Shear on Skewed Bridge Structures

2011 ◽  
Vol 255-260 ◽  
pp. 1244-1247
Author(s):  
Yi Zhou Zhuang ◽  
Tao Ji ◽  
Bao Chun Chen
Keyword(s):  
Load Distribution ◽  
Distribution Factor ◽  
Skew Angle ◽  
Shear Distribution ◽  
Moment Distribution ◽  
Bridge Structures ◽  
Skewed Bridge ◽  
Aashto Lrfd ◽  
Skew Angles ◽  
Bridge Models

Based on FEA for three bridge models with varying skew angles, the effect of skew angle on the design moment and shear of skewed bridge structures was studied and also compared to AASHTO specifications. The results show that, generally, ASSHTO-LFD covers FEM in moment distribution factor, but a little less in shear distribution factor, and that, however, AASHTO-LRFD reduces moment distribution factor below AASHTO-LFD and near to FEM, but increases shear distribution factor a lot beyond AASHTO-LFD and FEM.

Girder moments in simply supported skew composite bridges

1996 ◽  
Vol 23 (4) ◽  
pp. 904-916 ◽  
Author(s):  
Tarek Ebeido ◽  
John B. Kennedy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Parametric Study ◽  
Distribution Factor ◽  
The Finite Element Method ◽  
Simply Supported ◽  
Moment Distribution ◽  
Composite Bridges ◽  
The Moment ◽  
Element Method

The evaluation of girder moments in composite bridges becomes more urgent with the trend to increasing truck loads. The method specified by the American Association of State Highway and Transportation Officials for such an evaluation depends only on the centre-to-centre girder spacing. This method does not account for skew and therefore is extremely conservative for skew composite bridges, since the presence of skew reduces the longitudinal moments in the girders. The method proposed by the Ontario Highway Bridge Design Code (OHBDC) depends on the longitudinal and transverse rigidities of the bridge in addition to the girder spacing. However, this method is limited to bridges with skew parameters less than a certain value specified in the code. In this paper, the influence of skew on the moment distribution factor is investigated. Furthermore, the influences of other factors such as girder spacing, bridge aspect ratio, number of lanes, number of girders, and intermediate transverse diaphragms on the moment distribution factor are examined. An experimental program was conducted on six simply supported skew composite steel–concrete bridge models. The finite element method was used for the theoretical analysis. Good agreement is shown between the experimental results and the theoretical results. In addition, the finite element method was employed to conduct an extensive parametric study on more than 300 prototype composite bridge cases. The data generated from the parametric study were used to deduce expressions for the moment distribution factor for OHBDC truck loading and for dead load. An illustrative example is presented. Key words: bridges, codes of practice, composite, distribution, moment, reinforced concrete, skew, structural engineering, tests.

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 distribution in continuous composite bridges

1983 ◽  
Vol 10 (3) ◽  
pp. 384-395 ◽  
Author(s):  
John B. Kennedy ◽  
N. F. Grace
Keyword(s):  
Load Distribution ◽  
Transverse Load ◽  
Design Parameters ◽  
Skew Angle ◽  
Composite Action ◽  
Transverse Cracking ◽  
Composite Bridges ◽  
Current Design ◽  
Bridge Models ◽  
Concrete Deck

The influence of transverse diaphragms on the load distribution in composite bridges has been minimized in current design codes. Tests have shown that when diaphragms having an I-section are rigidly connected to the longitudinal girders, a rigid gridwork is formed; this gridwork in composite action with the concrete deck distributes the wheel loads on the bridge in an orthotropic manner. In this paper, the influences of the number of diaphragms, aspect ratio, skew, and cracking of the concrete deck on the transverse load distribution in continuous composite bridges are examined. The theoretical results are verified and substantiated by tests on two 1/8-scale bridge models. The results indicate that such diaphragms, rigidly connected to longitudinal girders, significantly enhance the transverse load distribution, and thus a reduction in the design load for the girders results; the degree of this enhancement increases with increase in the width as well as the skew angle of the bridge. Furthermore, transverse cracking of the concrete deck at the intermediate support(s) does not appear to influence significantly the transverse distribution of the design parameters.

scholarly journals Investigation of Load Distribution Factors for Simply-Supported Composite Multiple Box Girder Bridges

2021 ◽  
Author(s):  
Siham Kadhim Jawad
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
Load Distribution ◽  
Shear Force ◽  
Bending Moment ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Simply Supported ◽  
Girder Bridges ◽  
Load Distribution Factors

Composite box-girder bridges are recently used in modern highway urban system because of their profitable and structural aptitude advantages. North Americans Codes of Practice specify empirical equations for girder moment and shear forces in such bridges in the form of live load distribution factors. These factors were proven to be conservative in some cases and underestimate the response in other cases. Therefore, an extensive parametric study, using the finite-element modeling, was conducted to examine the key parameters that influence the load distribution factors of such bridges. A total of 276 prototype bridges were analyzed to evaluate girder bending moment, shear force and deflection distribution factors for simply-supported composite multiple box-girder bridges when subjected to CHBDC truck loading. Design parameters considered in this study were bridges span length, numbers of design lanes, number of box girders and girder spacing. Based on the data generated from parametric study, sets of simple empirical expressions were developed for bending moment; shear force and deflection distribution factors for such bridges. A correlation between the finite-element results with CHBDC and AASHTO-LRFD empirical expressions showed the former are more reliable in structural design of composite box-girder bridges.

Wheel Load Distribution on Simply Supported Skew I‐Beam Composite Bridges

1993 ◽  
Vol 119 (2) ◽  
pp. 399-419 ◽  
Author(s):  
Alfred G. Bishara ◽  
Maria Chuan Liu ◽  
Nasser D. El‐Ali
Keyword(s):  
Load Distribution ◽  
Wheel Load ◽  
Simply Supported ◽  
Composite Bridges

Skew composite bridges — analyses for ultimate load

1995 ◽  
Vol 22 (6) ◽  
pp. 1092-1103 ◽  
Author(s):  
Alaa Helba ◽  
John B. Kennedy
Keyword(s):  
Finite Element ◽  
Ultimate Load ◽  
Ultimate Limit State ◽  
Yield Line ◽  
Skew Bridges ◽  
Truck Loading ◽  
Composite Bridges ◽  
Composite Bridge ◽  
Bridge Models ◽  
Line Analysis

The ultimate limit state design for composite skew bridges with slab-on-I-steel girders requires a reliable prediction of their ultimate load capacity. In this paper, the results from a yield-line analysis of prototype composite bridges subjected to OHBDC truck loading are presented and compared with the results from a nonlinear finite element analysis of such prototype skew bridges. The favourable comparison between the two sets of results indicates that the collapse loads of skew composite bridges can be reliably and readily predicted by the yield-line method of analysis. Equations useful for the design and analysis of skew bridges are given. The experimental results from five composite bridge models tested to failure verify and substantiate the analyses. Results of the ultimate loads of six other skew composite bridge models with punched-to-failure deck slabs are also shown. A general and simplified method relating OHBDC truck loading to the collapse load predicted using the yield-line analysis is presented. Key words: analysis, bridges, composite, design, failure patterns, finite element, models, skew, yield-line.

scholarly journals Load distribution in concrete solid slab bridges

2021 ◽  
Author(s):  
Muhammad Ishtiaq
Keyword(s):  
Parametric Study ◽  
Plate Theory ◽  
Torsional Rigidity ◽  
Empirical Equations ◽  
Design Code ◽  
Shell Elements ◽  
Shear Distribution ◽  
Truck Loading ◽  
The Moment ◽  
Slab Bending

Canadian Highway Bridge Design Code (CHBDC) specifies empirical equations for the moment and shear distribution factors for selected bridge configurations. These empirical equations were based on the orthotropic plate theory with equivalent slab bending and torsional rigidity. Also, they were based on analysis procedure and CHBDC truck loading condition slightly different from those specified in the current CHBDC code of 2006. In this study, a parametric study was conducted, using the finite-element modeling to determine the moment and shear distribution factors for solid slab bridges subjected to CHBDC truck loading. Shell elements were used to model the bridge deck slab supported over bearings on each side of the bridge at 1.2 m spacing. The results from the parametric study were correlated to those available in the CHBDC code. Results show considerable difference in FEA results and CHBDS equations, especially for shear distribution factors. This project provides research results that can be used further to develop more reliable expressions for moment and shear distribution factors for solid slab bridges.

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