ABSTRACT
Underpinning is the process of strengthening the foundation of an existing structure due to various reasons, such as changes in usage of structure, inadequate original foundation strength or construction like excavation and tunnelling nearby the existing structure foundation. Nowadays, underpinning is commonly used in the construction industry as it is more economical in general, strengthening the present structure’s foundation than building the new one. The same concept was adopted at Mirage Tower, existing multi-storey building, located at 80 Kim Seng Road due to undercrossing of Thomson East Coast Line (TEL) tunnels. Even though said “Underpinning”, different existing site constraints make challenges in underpinning design and construction are unique for each underpinning work. This paper discusses about how the underpinning design appear based on the existing site constraints and design changes along the way due to additional constraints to attain the workable solution until the construction phase.
