Comparative Seismic and Cost Analysis of OMRF and Shear Wall Systems for a 15-Story RC Building in Jeddah

Abstract

Objectives: The objective of the study was to compare and contrast the seismic performance and material-based construction cost of two reinforced concrete structural systems of the 15-story building in Jeddah, Saudi Arabia, namely the Ordinary Moment Resisting Frame system and the reinforced concrete shear wall system. This was done to find out which system offers a more efficient compromise between structural response and starting material cost given the same design, loading and taking into consideration the code.   Methods: ETABS v22 was used to create two three dimensional analytical models of a 15-story reinforced concrete building with total height of 45 m. The former model was the Ordinary Moment Resisting Frame system and the latter was the reinforced concrete shear wall system. Both models were evaluated with the same geometry, material properties, and gravity loads, seismic loads, and the design-code requirements under the ACI 318-19, ASCE 7-16, and SBC 304-24. The two systems were compared with respect to fundamental period, base shear, story displacement, interstory drift and torsional response through the linear dynamic response spectrum analysis. The extracted concrete and reinforcement quantities of the analytical models were also used to compare costs based on materials. Results: The findings indicated that reinforced concrete shear wall system had superior seismic performance compared to Ordinary Moment Resisting Frame system. The fundamental period of the system reduced to 1.61 s in the shear wall system as compared to 2.53 s in the OMRF system, which illustrated increased lateral stiffness. The Ex load case reduced the maximum lateral deflection to 21.03 mm as compared to 46.04 mm and the interstory drift reduced to 0.0006 as compared to 0.0013. The OMRF system needed 7,631 m3 of concrete and 967 tons of reinforcement steel as compared to shear wall system which needed 7349 m3 of concrete and 878 tons of reinforcement steel. The approximate cost of the structural material-based on the unit rate of 250 Saudi Arabian Riyal (SAR)/m³ of concrete and 3,200 SAR/ton of reinforcement steel was 5,001,850 SAR in the OMRF system and 4,646,278 SAR in the shear wall system respectively.     Conclusions: The reinforced concrete shear wall system was determined to be more effective in the chosen 15-story structure in Jeddah since it offered increased lateral rigidity, diminished displacement, reduced interstory drift, and decreased structural cost in terms of material. Nevertheless, the results may be seen in the context of the constraints of the chosen linear dynamic analysis and material-based cost estimation.