BOND-SLIP LAW BETWEEN TIMBER AND NEAR SURFACE MOUNTED REBAR CONSIDERING LOCATION FUNCTION

The mechanical properties of timber structure components can be improved significantly with the near surface mounted technique, and the strengthening effects depend on the collaborative working performance between timber and rebars. The bond-slip constitutive relationship is the necessary basis for the theory calculation and finite element analysis. On the basis of the pull-out test results of 18 timber specimens (6 groups) with near surface mounted rebars, the distribution of the local bond stress and local relative slip-displacement along the anchorage length of steel rebars were obtained by analyzing and calculating the experimentally measured strain of steel bars and the relative-slip values of steel rebars to the end of specimens. The distribution law of local bond stress indicates that it is bimodal and the local relative slip-displacement curves are related to anchorage length. Further, the local bond-slip curves, the distribution of which varies along the measurement position and the bond stress distribution curves under the same slip value are analyzed. Then, a location function describing the bond-slip relationship is derived by the normalization method, and the influences of diameter and anchorage length of steel rebars on the distribution of the location function are discussed. Finally, the bond-slip law between timber and near surface mounted steel rebar considering the location function is constructed.