The University of Massachusetts Amherst
University of Massachusetts Amherst

Search Google Appliance

Links

Instrument to evaluate remaining prestress in damaged prestressed concrete bridge girders

TitleInstrument to evaluate remaining prestress in damaged prestressed concrete bridge girders
Publication TypeJournal Article
Year of Publication1998
AuthorsCivjan SA, Jirsa JO, Carrasquillo RL, Fowler DA
JournalPCI Journal
Volume43
Issue2
Start Page62
Pagination62-71
Date Published04/1998
Abstract

The decision of whether to repair or replace a damaged prestressed concrete bridge girder can be very difficult when a reliable estimate of prestress remaining in the strands is not available. A prototype  instrument has been developed to estimate stress levels in exposed prestressed strands in existing members. The stress level is determined by application of a lateral force to an exposed strand and  measuring the resulting displacement. The instrument was calibrated for 0.5 in. (12.7 mm) diameter seven-wire strand with exposed lengths of 7.5 to 3.75 ft (0.46 to 7. 7 4 m). It was tested to determine  its accuracYt precision, and usefulness in the field. Strand forces were consistently estimated to within 7 0 percent of the actual load. The device was also utilized in the placement of strand splices and was  found to be more reliable in checking induced strand tensions than the standard torque wrench method.