Evaluating Impact of Adjacent Tall Buildings on Seismic Response of Underground Structures: Fid-Bau Portal

Evaluating Impact of Adjacent Tall Buildings on Seismic Response of Underground Structures

Basarah, Yuamar I. / Numanoglu, Ozgun A. / Hashash, Youssef M. A.

Underground structures are commonly constructed near existing or new tall buildings in dense urban areas. Tall buildings, during earthquake shaking, generate base shear that is carried by the building foundation and surrounding soils. This base shear may be transmitted to adjacent underground structures. A previous study was conducted by combining dynamic centrifuge tests and numerical simulations to evaluate the impact of highly idealized adjacent tall buildings on the seismic response of underground structures. The numerical model can reproduce the seismic behavior observed in the centrifuge including the additional loading demands imposed by adjacent building on underground structures. Furthermore, a large-scale parametric study using three-dimensional (3D) nonlinear finite element analysis with more realistic soil-structure-underground structure (SSUS) representation is performed to evaluate the impact of variability in the SSUS system on the seismic response of underground structures. The effects of different building heights, building foundations, underground structure configurations, and soil profiles are evaluated using a suite of ground motions. The results show that (1) as the adjacent building became taller and hence the base shear increased, greater dynamic earth pressures were transmitted to the underground structure, (2) the dynamic earth pressures were reduced with increasing building to underground structure distance, and (3) the racking displacements of underground structures were strongly dependent on building foundation and underground structure configurations such as basement depth, pile length, and the depth of the underground structure. For design purposes, these interactions need to be considered by modeling a realistic building and underground structure representation in SSUS system to evaluate the added demands that a given building will impose on underground structures including cut-and-cover boxes and bored tunnels.