Bond mechanism of grout sleeve splicing for steel-FRP composite bar and pullout behavior of the bar with anchor head in concrete

Abstract

<p>The steel-fiber reinforced <a href="https://www.sciencedirect.com/topics/materials-science/polymer-composite" title="Learn more about polymer composite from ScienceDirect's AI-generated Topic Pages">polymer composite</a> bar (SFCB) can be used in concrete structures in harsh environments. However, their connection and end anchoring problems still need to be solved. Therefore, this article conducted <a href="https://www.sciencedirect.com/topics/engineering/tensile-test" title="Learn more about tensile tests from ScienceDirect's AI-generated Topic Pages">tensile tests</a> on grout sleeve splicing of SFCBs and <a href="https://www.sciencedirect.com/topics/engineering/pullout-test" title="Learn more about pullout tests from ScienceDirect's AI-generated Topic Pages">pullout tests</a> on SFCBs with anchor heads in concrete. Results indicate that bond performance between SFCBs and grout is independent of sleeve material (steel or GFRP) and <a href="https://www.sciencedirect.com/topics/engineering/bar-diameter" title="Learn more about bar diameter from ScienceDirect's AI-generated Topic Pages">bar diameter</a>. The thickness of <a href="https://www.sciencedirect.com/topics/materials-science/glass-fiber-reinforced-plastic" title="Learn more about GFRP from ScienceDirect's AI-generated Topic Pages">GFRP</a> at the rib position of the steel bar should be at least 2 mm to avoid making the peak stress declining. To eliminate the influence of grout thickness on bond behavior, curing specimens in the water is necessary. Splitting slip, <a href="https://www.sciencedirect.com/topics/engineering/peak-slip" title="Learn more about peak slip from ScienceDirect's AI-generated Topic Pages">peak slip</a> and residual slip increase with rib spacing. Residual stress decreases with the ratio of rib spacing to rib height. Peak stress and residual slip increase with <a href="https://www.sciencedirect.com/topics/materials-science/compressive-strength" title="Learn more about compressive strength from ScienceDirect's AI-generated Topic Pages">compressive strength</a> of grout. The ratio of splitting slip to peak slip varies little. The theoretical bond-slip curve is obtained, and the correlation coefficients between characteristic parameters and experimental values are 0.75–0.99. The peak splitting force is 43 % of the peak load. The differential equation has been established and solved, and results agree well with the test values. The minimal anchorage length of SFCBs (7 times the diameter) and its simplified calculation formula are obtained. Concrete <a href="https://www.sciencedirect.com/topics/materials-science/mechanical-strength" title="Learn more about strength from ScienceDirect's AI-generated Topic Pages">strength</a>, anchor-head length and tube material (steel or GFRP) do not affect pullout load-slip curves of SFCBs in concrete.<br></p>