Dimensjonering og analyse av fiberarmert polymer som armeringsstenger i plattendekke
Abstract
Fiber reinforced polymer (FRP) is an advanced composite which offers high capacity in tensilestrength, low weight and excellent corrosion resistance. Rebars made from basalt-, glass- and carbonfibers are readily available in the marked, but the practical use in the construction industry is limitedbecause of less knowledge and no codes or standardization. This thesis studies the use of FRP-rebarsin lattice girder slabs to compare the effect the rebar has on longer spans compared to regular steelreinforced lattice girder slabs. Both non-tensioned and pre-tensioned alternative have been studiedwith a variable thickness and length. Design manuals and codes from American Concrete Institute(ACI) and Canadian Standards Association (CSA), as well as the American Association of StateHighway and Transportation Officials (AASHTO) has been used to calculate the capacity of the slabregarding flexural deflection, moment capacity and shear capacity. The lattice girder slab has alsobeen dimensioned with regular steel reinforcement in accordance with Eurocode 2, for acomparison. Finite Element Method (FEM) has also been used to validate the results and study theload-deflection difference of the different material properties. Additional study has been done onbond and fire resistance for FRP-rebars embedded in concrete structure.Throughout the study it has been found that large spans with FRP-rebar have challenges when itcomes to flexural deflection. This is mainly due to low modulus of elasticity which contributes to lesslongitudinal stiffness compared to steel. By pre-tensioning FRP-rebar it is possible to overcome thisand take advantage of the high tensile strength to pretension with camber, especially for carbonfiber rebars. Bond between FRP-rebar and concrete is usually as good or some cases better thatribbed steel rebar if surface has been treated with sand coating or helical twinned fibers. Fireresistance is generally low because of matrix low glass transition temperature and extra cover isnecessary for protection.