Clock spring company, inc.

RenewWrap® Strand Sheet

RenewWrap® Strand Sheets are unidirectional reinforcement sheets consisting of an assembly of pre-cured carbon fiber micro bars. They are available in various stiffnesses and may be used to strengthen existing concrete or steel structures by external bonding. These reinforcement sheets combine the best features of traditional wet lay-up fabric and pre-cured plate FRP system.

This material was inspired by Japanese bamboo blinds — it consists of hundreds of pre-cured carbon fiber micro-rods assembled into a sheet bonded to a structure with epoxy resin. The resin allows the strand sheet to be uniformly bonded to an existing structure. The material can be spliced in the field by overlapping, like a wet lay-up system, and the quality of the bond line is visible by uniformity and complete coverage of carbon fiber strands.

The rehabilitation of the 1,090-foot-long Honjo Truss Bridge was one of the first RenewWrap® Strand Sheets applications to a steel structure. This steel truss superstructure was weakened from the corrosion of truss members — where the diagonal members penetrated the concrete deck — and the sufficient section loss required strengthening. The deck was removed around the truss members and the carbon strand sheets bonded to the webs and flanges of the W-beams comprising the diagonal members. Thirty-six diagonal members were strengthened with strand sheets, and the area of the bridge was painted after the sheets were finished curing.