GRC PERMANENT FORMWORK

Existing practice in the design and performance of grc (glass fibre reinforced concrete) formwork is described. Experiments with varying designs and spans have been carried out at the transport and Road Research Laboratory and in-situ to test the bond between the grc and concrete formwork. The authors present the factors which need consideration at the various stages of construction: (1) shrinkage of the in-situ concrete which is restrained by the panel; (2) the panel has to carry its own weight and weight of the in-situ concrete; (3) intake of water by the panel leading to expansion and thus imposing force on the concrete; (4) shrinkage of the in-situ concrete restrained by the panel; (5) creep relieves internal strain; (6) the live load and removable dead load will be carried in composite action. The differential natural strains in both components can cause stress which should be taken into account. Equations are derived which calculate the stresses at various stages for any configuration of slab and shutter panel. The formulae show that tensile strength in the panel, due to shrinkage and loading will lead to compression and cracking. The Department of Transport has set interim guide line limits of 0.5mm for cracking in the panel and 0.25mm for a crack in the slab. Attention is drawn to the contribution of arching to the reduction of tensile stress in the extreme fibre. Cases of trial sections are described in which the above mathematical formulae have been applied. Finally considerations are presented on an improved economical design for corrugated panels and on the manufacturing process, checking, site handling and transportation of grc products.

  • Availability:
  • Corporate Authors:

    INSTITUTION OF HIGHWAYS & TRANSPORTATION

    6 ENDSLEIGH STREET
    LONDON,   United Kingdom  WC1H 0DZ
  • Authors:
    • BRIDLE, R J
    • North, G G
  • Publication Date: 1988-10

Language

  • English

Media Info

  • Pagination: p. 26-31
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00487058
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS, ATRI
  • Created Date: Sep 30 1989 12:00AM