Enhancement of buckling capacity of steel plates strengthened with GFRP plates

The current study assesses the enhancement in the buckling capacity of steel plates through bonding glass fibre reinforced polymer (GFRP) plates. Despite their low modulus of elasticity, GFRP plates are relatively thick and, therefore, can be efficient in magnifying the buckling capacity of the retrofitted steel plates. In this application, a heavy duty adhesive system that was tested in a previous experimental programme is employed to bond the steel and the GFRP plates. The current study is conducted numerically using a nonlinear shell element model to simulate the steel and GFRP plates and a special contact element to simulate the flexibility of the adhesive medium. The failure modes in the adhesive and the GFRP plates, based on real strength values, as well as the instability of the entire system are considered. A buckling magnification factor relating the capacity of the retrofitted system to the capacity of the corresponding bare steel plate is evaluated. The study considers two types of boundary conditions as well as two types of in-plane compatibility between the steel and GFRP plates. The effect of geometric imperfection is also studied. Both elastic and inelastic stability analyses are considered in this investigation.

► The consistent shell element is used to simulate both the steel and GFRP plates.
► A continuous linear spring system is derived and is used to simulate the adhesive bonding the steel and GFRP plates.
► A significant enhancement in the buckling capacity is observed for slender steel plates retrofitted with GFRP.
► The failure mode changes from elastic buckling to either GFRP or adhesive failure with the increase of the GFRP thickness.
► Geometric imperfection reduces buckling capacity enhancement of steel/GFRP system by 56%.