BridgeSight Solutions

for the AASHTO LRFD Bridge Design Specification

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BridgeSight Solution for March 1999

Contraflexure Points for Continuous Highway Bridges [Click to view or Right Click to Download and Save]

BridgeSight Software is proud to share with you this time saving design aid for the AASHTO LRFD Bridge Design Specification. Several of the equations and procedures given by the specification make use of effective span lengths, most notably Article 3.6.1.3.1 application of the dual truck train element of the HL93 live load, Article 4.6.2.2.1 live load distribution factors, and Article 4.6.2.6 effective flange width. The effective span lengths are taken to be the distance between points of contraflexure due to either the permanent weight of the structure or a unit uniform load applied over the entire length of the structure, depending upon the provision.

This design aid tabulates the points of contraflexure for two , three, and four span prismatic, continuous bridges subjected to a unit uniform load, for a total of 456 unique configurations.

All of the three and four span configurations are symmetrical about their centerline.

While the tables present discrete bridge configurations, the intervals between span lengths and span ratios are small enough to permit linear interpolation without significant error.

History

May 4, 1999 Version 1.1 Update.  Fixed errors in Table 2.0 US, Table 2.2 SI and Table 2.2 US

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