Experimental Study On Impact Behavior Of RC Beams Without Stirrups Strengthened With CFRP Sheets Under Shear Load

In recent years, reinforced concrete structures are damaged due to the impact of extreme load excited by earthquakes, explosions and collision, which may cause mass casualties and a great property loss. As an advanced reinforcement material, the carbon fiber reinforced polymer(CFRP) composites play an important role and have got rapid development in practical engineering. Under the impact loads, structures are subjected to complex stress wave propagation and inertial effect, which makes their structure behavior more complicated. In the fiber reinforced concrete structures, there are still few researches on the behavior of r einforced concrete beam without stirrups under dynamic loads. The number of reinforced concrete test beams under impact load is still very limited, and the research on inertial effect in the process of impact effect is not detailed enough. Consequently, inertial effect is the key point of the research on the impact resistance. This research uses bending test to study the shear resistance of reinforced concrete beams without stirrups retrofitted with CFRP composites under static and dynamic loads. Specific contents of this study are summarized as follows:(1) Through the static loading test of the reinforced concrete beam without stirrup, the load-deflection curve, the strain distribution of the rebar and the CFRP strip are derived, and the influence of the different CFRP strip spacing on the shea r capacity and failure mode are researched.(2) Through the dynamic loading test of the reinforced concrete beam without stirrup, we study the fracture morphology and its developing process, impact load, end reaction, mid-span deflection and acceleration of the beams with different strengthening methods under different impact speed and impact energy.(3) By comparing the static and dynamic test results, the shear capacity and energy dissipation capacity of the reinforced concrete beam strengthened by CFRP under the impact load are summarized, which provide s the basis for the practical engineering design.