Enhanced rational horizontal tying force method for practical robustness design of building structures

Abstract

Under the backdrop of the rational horizontal tying force method recently developed at Imperial College London, which focuses on the tying resistance of floor systems based on constant tying forces and its planar interaction with the surrounding structure alone, this paper presents relevant enhancements to the original method. These enhancements involve simplified mechanics-based models quantifying i) the residual flexural resistance arising from the curtailed reinforcement in tying via beams, ii) the additional flexural resistance from transverse beam in one-way tying via floor systems and iii) the planar restraint stiffness from the surrounding structure, including the influence of the compressive ring mobilised within the affected floor system under tensile membrane action. Following a detailed exposition of the formulation of the models, the paper presents several studies which demonstrate the effectiveness of the enhanced tying force method. Importantly, the method addresses resistance and stiffness mechanisms not covered in the current prescriptive tying requirements within a practical application framework that is still comparable in simplicity to such requirements, thereby further promoting the rational horizontal tying force method as a potential replacement for the prescriptive tying requirements in the next generation of robustness design codes.