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Abstract
Reinforced concrete deadman anchors are used by the nonprofit humanitarian organization Bridges to Prosperity [B2P] to arrest the suspension cables of pedestrian bridges they build in developing countries. The design methodology they use to determine the pullout capacity of these anchors relies on considering failure either in
uplift or sliding, but not both in tandem. The focus of this research was to investigate the failure mechanics of a concrete anchor buried in dry, cohesionless soil as it is pulled by cables resisting the load of a pedestrian bridge. The research employed two major methods: a theoretical pullout capacity based on the limit equilibrium theorems of Meyerhof; and two-dimensional finite element modeling that was verified by quantitative and qualitative scale model testing. The results of the finite element modeling were used to create design charts based on anchor length, anchor height, soil density, soil internal
friction angle, embedment depth, and the pullout angle of the cables. The results showed good correlation with what is predicted by Meyerhof’s limit equilibrium equation but
show that B2P’s design methodology is overly conservative. The results of this research should be verified by full-scale or partial-scale model testing before any changes are adopted by B2P or their members, but it appears that limit equilibrium could be used as a
working theoretical solution. Other variables that affect anchor pullout and are not covered in this research also need to be investigated for a more complete understanding of deadman anchor pullout capacity, including soil angle of dilatancy, cohesion, moisture
content, sloping ground surfaces, modulus of elasticity, Poisson’s ratio, and end effects.