The effect of foundation type selection on approximate cost of reinforced concrete buildings: the role of soil classes and number of floors

Abstract

This study investigates the choice of foundation type, which is one of the factors affecting the approximate cost of rough construction of buildings with reinforced concrete structural systems. In the study, isolated, continuous and raft foundation types are discussed comparatively for buildings with different numbers of floors (1-4 floors above the basement) and different soil classes (ZB-ZE). In the literature, there is no study in which the effects of foundation type, number of floors and soil classes on the approximate cost of a building are analyzed together. This study aims to fill this gap in this field. Reinforced concrete design and analysis were performed using Protastructure 2022 software; concrete, formwork and reinforcing steel quantities were calculated, and approximate costs were calculated with the Republic of Türkiye Ministry of Environment, Urbanization and Climate Change 2024 Construction and Installation Unit Prices (TCÇŞİDB 2024) and the results were presented in tables and graphs. According to the study's findings, as the soil class improves, isolated foundations are more economical than other foundations. In contrast, the cost of isolated foundations increases significantly as the soil class deteriorates and the number of floors increases, while the cost difference between continuous foundation and raft foundation decreases.