THE CONCRETE BRIDGE MAGAZINE

SPRING 2011

ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

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52 | ASPIRE , Spring 2011 A A S H T O L R F D T he Fifth Edition of the AASHTO LRFD B r i d g e D e s i g n S p e c i f i c a t i o n s wa s published in 2010. It was subsequently revised when the American A ssociation of State Highway and Transportation Officials (AASHTO) Subcommittee on Bridges and Str uctures (SCOBS) considered and adopted changes at their annual meeting in Sacramento, Calif., in May of 2010. Technical Committee T-10, Concrete Design, developed Agenda Items 22, 23, and 31 over the past several years and moved them to the full subcommittee ballot during this meeting. These revisions are described in this article. Agenda Item 22 adds provisions to Article 5.11.5.2.1 for lap splices of reinforcement. Based on research published in the Washington State Department of Transportation (WSDOT) Tr a n s p o r t a t i o n C e n t e r ( T R A C ) R e p o r t WA-RD 417.1, titled "Noncontact Lap Splices in Bridge Column-Shaft Connections," an equation was added to limit the spacing of transverse reinforcement in the splice zone of such shafts. The provisions are for columns with longitudinal reinforcement that anchors into oversized drilled shafts, where the bars are spliced by noncontact lap splices, and the longitudinal column and shaft reinforcement are spaced farther apart transversely than one- fifth the required lap splice length or 6 in. Agenda Item 23 deleted provisions and commentar y from Article 5.12.2 relative to aggregates that are known to be excessively alkali-silica reactive (ASR). These provisions and the commentar y related to the testing of aggregates for ASR were deemed more appropriate for the AASHT O LRFD Bridge Construction Specifications . Appropriate r efer ence was made to the Constr uction Specifications. As a companion to Agenda Item 23, Agenda Item 31 was approved in conjunction with SCOBS Technical Committee T-4, Construction. Through this agenda item, the provisions deleted from the LRFD Bridge Design Specifications in Agenda Item 23 were revised, updated, and inserted into the LRFD Bridge Construction Specifications. These and the complete set of 2011 Interim Revisions to the AASHTO LRFD Bridge Design Specifications will be published in 2011 by AASHTO. If you would like to have a specific provision of the AASHTO LRFD Bridge Design Specifications explained in this series of articles, please contact us at www. aspirebridge.org. 2011 Interim Revisions Related to Concrete Structures by Dr. Dennis R. Mertz EdItoR'S NotE AASHTO_Spr11.indd 52 3/30/11 5:21 PM

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