Abstract: A new type of CFRP stirrup production process was proposed, and a new type of closed composite wire winding CFRP stirrup was designed and manufactured, which is characterized by direct winding of carbon fiber composite wire, avoiding the problem of weak tensile strength of stirrup caused by folding at the bend, and improving the performance of traditional pultrusion FRP stirrup at the bend. The effects of bending radius, multiple wire layers, stirrup width and concrete strength on the tensile strength of CFRP stirrup were analyzed by orthogonal experiment. The results show that the number of multiple wire layers is the biggest factor affecting the tensile strength at the bending point of the new enclosed composite wire wound CFRP stirrup, and it is inversely proportional to the tensile strength at the bending point of the stirrup. Secondly, with the increase of stirrup width and bending radius, the tensile strength of stirrup increases, and the linear relationship is approximately positive. The influence of concrete strength on the tensile strength at the bend of stirrup is not obvious, and there is no obvious rule. The results show that the new process can obviously improve the tensile strength compared with the traditional process, and has a good engineering application prospect.

Key words: bending strength, CFRP stirrup, orthogonal test, stirrup technology, stirrup formula