| dc.description.abstract | Fiber reinforced polymer (FRP) is an advanced composite which offers high capacity in tensile
strength, low weight and excellent corrosion resistance. Rebars made from basalt-, glass- and carbon
fibers are readily available in the marked, but the practical use in the construction industry is limited
because of less knowledge and no codes or standardization. This thesis studies the use of FRP-rebars in lattice girder slabs to compare the effect the rebar has on longer spans compared to regular steel reinforced lattice girder slabs. Both non-tensioned and pre-tensioned alternative have been studied with 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 State Highway and Transportation Officials (AASHTO) has been used to calculate the capacity of the slab regarding flexural deflection, moment capacity and shear capacity. The lattice girder slab has also been dimensioned with regular steel reinforcement in accordance with Eurocode 2, for a
comparison. Finite Element Method (FEM) has also been used to validate the results and study the
load-deflection difference of the different material properties. Additional study has been done on
bond 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 it
comes to flexural deflection. This is mainly due to low modulus of elasticity which contributes to less
longitudinal stiffness compared to steel. By pre-tensioning FRP-rebar it is possible to overcome this
and take advantage of the high tensile strength to pretension with camber, especially for carbon
fiber rebars. Bond between FRP-rebar and concrete is usually as good or some cases better that
ribbed steel rebar if surface has been treated with sand coating or helical twinned fibers. Fire
resistance is generally low because of matrix low glass transition temperature and extra cover is
necessary for protection. | |
