Anchorage force transfer mechanism and bearing capacity theoretical of pawl bolt anchored in plain concrete.

In this paper, the anchorage mechanism and bearing capacity of the special type of pawl bolt anchored in concrete under uplift load were studied. Static tests were carried out on two typical pawl bolts, namely 135° and 180° pawl bolts, and the effects of anchorage depth and pawl type on their failure modes were studied. The experimental results show that the uplift bearing capacity of pawl bolt is improved more effectively than that of smooth bolt. The two typical failure modes of pawl bolts under uplift load are concrete breakout failure and bolt yield failure. The concrete breakout failure exclusively occurs with anchorage depth of 5 d , while the failure mode could change from concrete breakout failure to bolt yield failure with the increase of anchorage depth. The finite element model was established to elucidate the failure mechanism of anchorage bolt and concrete. The crack propagation and diffusion angle distribution of anchorage concrete can be directly judged by concrete tensile damage and stress vector in simulation analysis. Additionally, a calculation method to accurately predict the uplift bearing capacity of pawl bolt was proposed, which considered the effect of diffusion angle θ i on the uplift bearing capacity and further discusses the change law of cone diffusion angle θ i and concrete crack propagation. The calculated results exhibited a concordance with the experimental and numerical results, which shows that the formula presented in this paper can be considered reliable and can guide the practical engineering design. ● Studied design params' impact on pawl bolts force transfer mechanism and concrete cone diffusion angle. ● Examined concrete crack behavior under uplift load for pawl bolts. ● Proposed spatial angle-variation elliptic concrete cone calculation model for pawl bolts based on cone diffusion angle. [ABSTRACT FROM AUTHOR]