Mohammad Haji - Department of Civil Engineering, University of Tehran, Tehran, Iran
Mohammad Sadegh Marefat - Department of Civil Engineering, University of Tehran, Tehran, Iran
Ali Kheyroddin - Department of Civil Engineering, University of Tehran, Tehran, Iran

The use of FRP materials to strengthen reinforced concrete columns has gained a significantreputation in the construction industry due to its excellent advantages compared to steel, such as noncorrosion,non-magnetic properties, high tensile strength in relation to weight, better resistance to fatigueand ease of implementation. But the use of these materials as a stirrup for new columns has been recentlynoticed. Early studies focused on pultruded FRP stirrups and led to good results. However, no report hasbeen published regarding the composite wrap as a spiral in the new column, and it seems that studies inthis field are necessary. In this article, FRP strips are used as stirrups, and the behaviour of reinforcedcolumns with this type of stirrups is compared with columns with steel stirrups and pultruded FRPstirrups. The study is numerical and the changes in parameters such as distance of spiral pitches, numberof FRP layers and width of strips have also been investigated. The results show that increasing the stripwidth, increasing the number of layers, and reducing the spiral pitch improve the performance of thecolumns, while the effect of increasing the strip width is somewhat greater. Also, the use of FRP strips asreinforcement instead of steel stirrups or pultruded FRP spirals does not have a negative effect on thebehaviour of the column and leads to reliable and acceptable results.

Reinforced concrete column, Stirrup, Spiral strip, FRP, Finite element