Effects of Height and Plan Geometry on the Costs of Tunnel Form Residential Buildings

Abstract

Tunnel form systems, which are industrialised construction systems developed in the last century, are widely used in reinforced concrete projects. Accurate determination of the costs of the building properties in the design phases of construction with the tunnel form system can lead to lower construction costs. The purpose of this study is to examine the cost variations resulting from changes in geometrical characteristics of buildings in the architectural design phase. The research was carried out on residential projects, which have the biggest share in the construction sector. Six housing projects with different plan geometries were designed, and these projects were examined for nine different numbers of floors. The study aims to reveal the extent to which both the plan shape and the number of floors influence the building costs. During the design phase, recommendations are given for reducing the building costs and finding the optimal form. It has been shown that tunnel form projects are not cost-effective in low-rise buildings and after a certain height. Furthermore, when different geometries are examined, the most economical cost is obtained in square form, and the cost increases as the two dimensions in plan plane move away from each other. As a result, the data obtained from this study will provide a better assessment of the relationship between building properties and unit cost in buildings constructed with tunnel form systems.