Quantifying Shear Wall Quantity for Seismic Design Practice of Reinforced Concrete Buildings With One-way Joist Slabs

One- or two-way joist slab floor systems are commonly favored in modern residential reinforced concrete (RC) building applications due to their efficiency in architectural and structural design processes. However, a significant number of such buildings experienced heavy damage or collapse mechanisms during the catastrophic earthquakes in Turkey since they are more vulnerable due to some uncertainties in the design and construction stages such as relatively limited strength, stiffness, higher inertia forces and P -𝛥 effects and forces to be transferred in the parts passing outside column / shear wall. In this regard, although well-known seismic codes such as Eurocode, UBC, ASCE and NZS do not impose additional requirements for the design of structural systems with joist slabs, the seismic codes of some Mediterranean basin countries regulate the ductility levels, use of shear walls and member/system-based specific requirements. In the present study, the impact of shear wall quantity on the seismic behavior of RC buildings with one-way joist slabs was investigated on five-story structural systems, which are basically similar in terms of the slab properties and layout but have different overturning moment ratios (𝛼𝑀=𝛴𝑀 _{𝑏𝑎𝑠𝑒} 𝛴𝑀 _𝑂 ⁄=0.75,0.60,0.45,0). In this context, a total of 88 bi-directional nonlinear time history analyses were conducted on four structural systems, which are highly representative of buildings in the earthquake zones of Türkiye, under real earthquake ground motions. Hence, the seismic behavior demands—including story displacement, inter-story drift and plastic deformations, distributions of plastic hinges and member-based performance levels—were discussed by the overturning moment ratio that directly associates with the shear wall quantity in the system. It can be concluded that when these buildings are jointly designed with the shear walls and frames of high ductility level—through the capacity design principles—the stipulated performance objective can be successfully achieved by the criteria of 0.75>𝛼 _𝑀 ≥0.40 instead of the current TSC provision of 𝛼 _𝑀 ≥0.75.