| In virtue of the advantages of fiber-reinforced plastic/polymer (FRP), light-weight, high-strength, nice environmental and fatigue resistibility, it has been broadly used in structural strengthening in the past two decades. As a new strengthing technique, near-surface mounted (NSM) FRP reinforcement has many virtues than other reinforcement. It's accepted by lots of scholars and engineers. Sufficient tests are urgently needed to provide mature theory for practice.The bond mechanics of NSM FRP composites to concrete should be obtained first for it is the primary step in the whole investigation of NSM FRP reinforcement.A total of 9 specimens have been investigated in a new modified beam-shear test program in order to study bond behavior of NSM carbon-FRP (CFRP) strips to concrete. Three variables which are suspected influencing bond behavior of NSM CFRP strips to concrete have been investigated, including: loading mode,bonded length and adhesive. This thesis focuses on bond failure modes, failure mechanics, factors influencing bond behavior, bond shear stress-slip relationship and bond failure load.Based on the test results, the debonding mechanics between CFRP strips and adhesive is better understand. The slip of free end can be presumed zero. Taking it as the bond failure criterion, this paper gets the formula of bond failure load and also presents it tallies well with the test results and the existing numerical analysis method. Based on this, a ultimate limit state designed method is carried out. The debonding mechanics of dynamical load is dicussed. Based on this, the solution of bond differential equation (when CFRP doesn't slip at free bonded end, only using the first and the second part of the bond-slip curve) has been worked out. From this, the formula of bond failure load under dynamical load is also proposed.
|
PDF Full Text Request