Shear Performance of the GFRP Bolt Interface Between the GFRP Profile and UHPC/Concrete Slabs

ABSTRACT In order to assess the feasibility of employing glass fiber reinforced polymer (GFRP) bolts as a corrosion‐resistant solution for composite structures comprising GFRP and ultrahigh‐performance concrete (UHPC), the shear performance of GFRP bolts interface between UHPC and GFRP was investigated through push‐out tests. A total of seventeen GFRP–concrete push‐out specimens were tested, including eleven GFRP–UHPC specimens with a GFRP bolt interface, two GFRP–UHPC specimens with a steel bolt interface, and four GFRP–concrete specimens with a GFRP bolt interface. The experimental parameters included the concrete strength, bolt type, bolt embedment length ( h bolt ), bolt number ( n bolt ), bolt spacing ( s bolt ), and bolt diameter ( d bolt ). The results revealed three failure modes, that is, bolt shear shank failure, concrete failure, and GFRP flange shear failure. Under the same design parameters, the ultimate bearing capacity ( P u ) of GFRP bolt pull‐out specimens is 72.4% and 49% of 4.8 grade steel bolt and 8.8 grade steel bolt pull‐out specimens, respectively. The application of UHPC prevents concrete compression failure. Increasing the d bolt and the n bolt can significantly enhance the P u of the specimen, and the s bolt and h bolt have limited impacts on the P u . The “bilinear” model was proposed to predict the load–slip curve of the GFRP bolt interface between the FRP–UHPC push‐out specimens. Based on the experimental data, a calculation method was proposed to calculate the ultimate shear capacity of the GFRP bolt interface between the FRP‐UHPC specimens.