Abstract
Without demolishing an entire existing building, it is possible to sustainably expand its underground spaces to enhance the building’s functionality. However, there have been a few relevant studies exploring this option, and they did not consider the financial feasibilities of underground vertical extension methods. Therefore, this paper analyzes the economic impacts of three sustainable vertical extension methods for existing underground spaces. The extension methods were the (1) bottom-up, (2) normal top-down, and (3) top-down with multi-post downward (MPD) methods. In order to analyze and compare the economic impacts of the underground vertical extension methods, 24 illustrative examples were generated in this paper. Construction costs of the three sustainable vertical extension methods for existing underground spaces are calculated and compared. Those are based on the quantity of used materials in the construction phase and dismantled materials in the demolition phase, as well as unit costs of each material. In addition, the structural stabilities of the examples are analyzed using MIDAS Gen 2017. As the results, the top-down method with MPD was the lowest sustainable method for vertically expanding underground spaces compared to other two methods under the same condition. Moreover, the higher the number of underground floors of existing buildings and the greater the number of extended basement floors, the more economically advantageous was the top-down method with MPD. Considering their structural stabilities and economic impacts of the extension methods help practitioners to select appropriate construction techniques and reduce costs, risks, and the amount of generated construction and demolition waste.
Highlights
The use of underground space in buildings in congested urban areas has been increasing since there is a lack of available aboveground space [1,2,3,4] and the development of additional underground space in existing cities can provide new potential for urban development [5]
This paper analyzed the economic impacts of three vertical extension methods for basement floors of existing buildings, which were the bottom-up, normal top-down, and top-down with multi-post downward (MPD) methods
Extension cost of the three methods to sustainably expand underground spaces of existing buildings were calculated based on the quantity of used or demolished materials, their unit cost, and the assumed labor cost rate
Summary
The use of underground space in buildings in congested urban areas has been increasing since there is a lack of available aboveground space [1,2,3,4] and the development of additional underground space in existing cities can provide new potential for urban development [5]. Previous studies did not consider detailed excavation and construction processes based on various site conditions They did not analyze the economic feasibility of the proposed underground vertical extension methods for existing buildings. The three sustainable methods are bottom-up, normal top-down, and top-down multiple posts downward (MPDs) methods To analyze their economic impacts, construction costs of 24 illustrative examples to which three sustainable vertical extension methods for existing underground spaces are applied, are calculated, and compared. Their structural stabilities are analyzed using MIDAS Gen 2017.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
