Evaluation of performance of non‐invasive upgrade strategy for beam–column sub‐assemblages of poorly designed structures under seismic type loading

Abstract

Summary Beam–column sub‐assemblages are the one of the most vulnerable structural elements to the seismic loading and may lead to devastating consequences. In order to improve the performance of the poorly/under‐designed building structures to the critical loading scenarios, introduction of steel bracing at the RC beam–column joint is found to be one of the modern and implementable techniques. In the present work, a diagonal metallic single haunch/bracing system is introduced at the beam–column joints to provide an alternate load path and to protect the joint zone from extensive damage because of brittle shear failure. In this paper, an investigation is reported on the evaluation of tae influence of different parameters, such as angle of inclination, location of bracing and axial stiffness of the single steel bracing on improving the performance through altering the force transfer mechanism. Numerical investigations on the performance of the beam–column sub‐assemblages have been carried out under cyclic loading using non‐linear finite element analysis. Experimentally validated numerical models (both GLD and upgraded specimen) have been further used for evaluating the performance of various upgrade schemes. Cyclic behaviour of reinforcement, concrete modelling based on fracture energy, bond‐slip relations between concrete and steel reinforcement have been incorporated. The study also includes the numerical investigation of crack and failure patterns, ultimate load carrying capacity, load displacement hysteresis, energy dissipation and ductility. The findings of the present study would be helpful to the engineers to develop suitable, feasible and efficient upgrade schemes for poorly designed structures under seismic loading. Copyright © 2016 John Wiley & Sons, Ltd.

Minimally Invasive Retrofitting of RC Joints with Externally Applied SMA Plate—Adaptive Design Optimisation through Probabilistic Damage Simulation

“…Moreover, structural interventions need to have enhanced characteristics such as being rapid, minimally invasive, cost-effective and subsequently financially viable, in order to qualify as adequately resilient solutions. Some examples with various novel materials and techniques can be found in [4][5][6][7][8][9], and a state-of-the-art report and guidance in [10]. The research reported below seeks to address this issue with a focus on the use of advanced superelastic shape memory alloys for use at the critical joint locations of framed concrete structures.…”

A novel structural detailing for the improvement of seismic and progressive collapse performances of RC frames

“…Qu et al proposed an unconstrained gusset connection for the buckling restrained braces in RC frames to mitigate the complicated and harmful interactions between the gusset plate and the adjoining columns. Sasmal and Nath proposed a diagonal metallic single haunch/bracing system for protecting the beam‐column joints of poorly designed structures under seismic cyclic loading. In addition to these research efforts, other researchers have investigated the effects of different types of structural detailing on the progressive collapse resistance of RC beams.…”