SAIDEL Engineering has designed the first residential building above subway tunnels in western Bucharest, Romania. The Euro 2.5 million project was initiated by a land developer. The structure was initially planned as a 10-storey building with a basement for parking. As a pioneer project located in the tunnel protection zone, it had an irregular footprint and required approval from the subway operator. It was required to demonstrate minimal displacement of tunnels and effect on structural forces. SAIDEL Engineering was responsible for providing structural and geotechnical design, with the aim of reducing the overall effect of the building on the tunnel lining by providing a safe and cost-efficient foundation.
The project was complex and required SAIDEL Engineering to modify the shape of the footprint to reduce the irregularity of the building, while still complying with the functional and architectural demands. It was also required to obtain the conservative subway operator’s approval, which took two years. To enable the project to proceed as quickly as possible, the company needed to determine an innovative excavation plan and conceptual design for the foundation that was acceptable to the subway operator, Metrorex.
To fulfil Metrorex’s strict demands to minimise impact on tunnels, SAIDEL Engineering initially performed a 2D geotechnical analysis to determine and present feasible solutions for both the excavation and foundation that complied with the displacement and structural requirements. It also wanted to increase the safety of the conceptual foundation design through 3D geotechnical modelling and analysis. While it received approval for the excavation, SAIDEL Engineering sought to develop 3D models for improved accuracy and optimisation for the geotechnical design. “Given the sensitivity of the project, we desired to increase the safety of the solution,” says Serban Nicolau, FEM design engineer at SAIDEL Engineering.
SAIDEL Engineering faced numerous obstacles while modelling the piles and pier loads given the size of the model, which features more than 1.1 million elements and 1.5 million nodes. It needed an advanced geotechnical engineering application to provide the subway operator with accurate, quality design and documentation, proving that the structural foundation and the 10-storey residential building will have minimal influence on the tunnel lining.