Lateral Distribution Factors for Highway Bridges

Bakht, Baidar; Moses, Fred

doi:10.1061/(asce)0733-9445(1988)114:8(1785)

Cited by 35 publications

(25 citation statements)

References 3 publications

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“…By equating the right hand sides of equations (2) and (3), it can be shown that come to be known as the a-e method. By equating the right hand sides of equations (2) and (3), it can be shown that come to be known as the a-e method.…”

Section: The Hong Kong Institution Of Engineersmentioning

confidence: 99%

An Introduction to Simplified Methods of Bridge Analysis for Hong Kong

Chan

Bakht

Wong³

1995

HKIE Transactions

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Simplified methods for bridge designs have been allowed to use for many years by various North American bridge design codes. However such methods have not yet been permited to use in Hong Kong. The use of simplified methods will not only shorten the time spent on analysis, but will also permit the designer to retain a "feel" of behaviour of the bridge which is usually lost in traditional analyses. This paper constitutes the first report on the development of simplified methods of bridge analysis for use in Hong Kong. It presents the simplified method for the analysis of girder bridges with two lanes with the objective of generating discussion from practising designers which may lead to the enhancement of the proposed method and other methods currently under development. The results from the proposed method do not deviate significantly from those obtained by other analysis methods. The basis of simplified methods and various simplified methods adopted in recent North American bridge design codes are presented so as to give a better understanding of such methods to the bridge designers in Hong Kong. It is also interesting to find out that bridges in Hong Kong are considerably stiffer than their counterparts in north America.

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Section: The Hong Kong Institution Of Engineersmentioning

confidence: 99%

An Introduction to Simplified Methods of Bridge Analysis for Hong Kong

Chan

Bakht

Wong³

1995

HKIE Transactions

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“…The Ontario Highway Bridge Code uses live load distribution factors that have a similar S/D format to the US Standard Specifications (1991). However, the OHBDC prescribes a unique approach for determination of D d that is based on the research of Bakht and Moses (1988) and Bakht and Jaeger (1990). The recent adoption of the national Canadian Highway Bridge Code (CSA, 2000) has also incorporated the work of Bakht and Moses (1988) and Bakht and Bakht and Jaeger (1990).…”

Section: Ontario Highway Bridge Code [Ohbc] and The Canadian Highway mentioning

confidence: 99%

“…However, the OHBDC prescribes a unique approach for determination of D d that is based on the research of Bakht and Moses (1988) and Bakht and Jaeger (1990). The recent adoption of the national Canadian Highway Bridge Code (CSA, 2000) has also incorporated the work of Bakht and Moses (1988) and Bakht and Bakht and Jaeger (1990). However, this specification essentially uses a live load distribution factor in which the force effect of interest (i.e., moment of shear) is distributed based on the number of design lanes divided by the number of girders.…”

Section: Ontario Highway Bridge Code [Ohbc] and The Canadian Highway mentioning

confidence: 99%

Simplified live-load moment distribution factors for simple span slab on I-girder bridges

Hevener¹

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Live load distribution factors have been used in the design of highway bridges since the first edition of the AASHTO Standard Specifications were introduced in 1931. Revisions were made to the AASHTO Standard Specifications in 1943 based on work conducted by Newmark. These changes lead to the S/5.5 factor. In 1988, an effort was made to revise the AASHTO Standard Specification equation for live load distribution to produce less conservative results. NCHRP Report 12-26 successfully developed an equation involving girder spacing, girder span length, girder stiffness, and slab thickness; and was adopted into the AASHTO LRFD Specifications. The primary goal of this effort is to identify and assess various methods of computing live load distribution factors and to use the results of laboratory and field tests to compare these methods. It is further a goal of this work to use these methods to perform a parametric study over a wide range of typical slab on steel I-girder bridges to assess the accuracy of both the AASHTO Standard and AASHTO LRFD specifications and to propose an empirical model that correlates better with the analytical results within the range of parameters that are to be studied. These studies include: (1) a verification study into the FEA techniques used in modeling bridge geometry, (2) selection of procedure of calculating load distribution factors from FEA data, (3) a verification study of the selected procedure, (4) a parametric study to assess the influence of bridge parameters on the contribution to load distribution factors, (5) the development, using regression techniques, of a new equation for live load distribution factors, and (6) a comparison of proposed distribution factors against FEA, AASHTO LRFD, and AASHTO Standard Specifications. Results from this work that over a wide range of typical bridge parameters both the AASHTO Standard and LRFD Specifications may produce conservative results and indicate the proposed equation provides a good foundation for the development of new equations for live load distribution factors. Girder spacing and girder span length were found to have the most influence of load distribution. The proposed equation developed showed good correlation to the FEA data and also correlated well against actual DOT bridge inventories used in the development of the AASHTO LRFD equation for live load distribution factors in slab on steel I-girder bridges.

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“…. It was conceptually related to Ontario Highway Bridge Design Code (1991), which was based on the research by Bakht and Moses (1988) and Bakht and Jaeger (1990). F and f C were determined from tables and were functions of the type of bridge, class of highway, girder location (interior vs. exterior), and span length, while µ was determined by design lane width.…”

Section: Load Distribution Factormentioning

confidence: 99%

Design guidelines for FRP honeycomb sandwich bridge decks

Zou¹

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Fiber-Reinforced Polymer (FRP) Bridge decks offer great advantages in highway bridge rehabilitation and new construction, due to reduced weight and maintenance costs, and enhanced durability and service-life. In practice, however, lack of bridge engineering design standards and guidelines have prevented wider acceptance and application of FRP bridge decks by transportation officials. This dissertation focuses on the study of an engineered FRP deck-steel stringer bridge system through experimental testing and both Finite Element analyses and analytical methods. A prototype mechanical shear connection was developed and designed to be used with any type of FRP panels that can accommodate any panel heights. This non-grouted sleeve-type connector can secure the deck onto a welded stud and can sustain shear forces at FRP panelsteel stringer interface. Static and fatigue tests were conducted on push-out connection specimens, and later on a scaled bridge model. The strength, stiffness, and fatigue performance characteristics of the connection were fully investigated. Constructability issues were also evaluated, such as ease of installation and economic manufacturing of the connector. Design formulations were established based on the test results. Following the connection study, a 1:3 scaled bridge model of a honeycomb FRP deck on steel stringers was evaluated. The deck was attached to three supporting steel stringers using the proposed sleeve-type mechanical connections. The model was designed as partially composite to satisfy AASHTO limits and requirements. Several issues were evaluated that included: (1) deck attachment procedures; (2) transverse load distribution factors; (3) local deck deflections; and (4) system fatigue behavior. After the bridge model was tested in the linear range, a 1.2-m wide T-section, of an FRP deck section attached to the middle stringer, was cutout from the bridge model and tested in bending for service and failure loads. The evaluations included: (1) Degree of composite action, (2) Effective deck-width, and (3) service-limit and ultimate-limit states under flexure loads. The behavior of the FRP deck under partial composite action was defined fully by these tests.

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Lateral Distribution Factors for Highway Bridges

Cited by 35 publications

References 3 publications

An Introduction to Simplified Methods of Bridge Analysis for Hong Kong

An Introduction to Simplified Methods of Bridge Analysis for Hong Kong

Simplified live-load moment distribution factors for simple span slab on I-girder bridges

Design guidelines for FRP honeycomb sandwich bridge decks

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