Construction of the New Marlborough School in Kensington, London involved a new basement just 9m above a 3m diameter storm drain. This required a complex basement geometry around the exclusion zone and a detailed ground movement analysis to ensure the storm drain would not be compromised.

A 3D FEA model of the basement and underlying storm drain was used to demonstrate that the stress change and distortion of the drain were acceptable and also provide settlement, bending moment and spring stiffness values for the basement raft design.

Highlights

• 3D FEA model of the complex basement geometry, underlying rc segment lined storm drain and surrounding ground.

• Simulation of demolition of old school, excavation of basement and construction of new school.

• Output of stress changes and distortion of storm drain for acceptance by Thames Water.

• Output of basement raft settlement, bending moment and coefficients of subgrade reaction for structural design.