Numerical Investigations on Response of Multistorey Building Frames Subjected to Adjacent Unsupported Excavations

• Published in: Geotechnical and geological engineering Vol. 41; no. 2; pp. 1223 - 1245
• Main Authors: Mandala, Vishnuvardhan, Patel, K. A., Chavda, Jitesh T.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2023; Springer Nature B.V
• Subjects: Bending moments; Building frames; Buildings; Civil Engineering; Columns (structural); Constitutive models; Construction; Deformation; Deformation effects; Dredging; Earth and Environmental Science; Earth Sciences; Excavation; Forces (mechanics); Geotechnical Engineering & Applied Earth Sciences; Hydrogeology; Investigations; Mathematical models; Multistory buildings; Original Paper; Parameters; Raft foundations; Safety factors; Sensitivity analysis; Shear forces; Soil; Soils; Structural integrity; Terrestrial Pollution; Urban areas; Urbanization; Waste Management/Waste Technology; Finite element method; Stability of open excavation; Mohr–Coulomb model; Linear–Elastic model; Multistorey building frame; Factor of safety
• ISSN: 0960-3182; 1573-1529
• DOI: 10.1007/s10706-022-02331-2

Due to rapid urbanization, open excavations are not uncommon these days. However, many issues are arising during the execution of unsupported open excavations when not designed and executed properly. Moreover, in urban areas where new buildings are constructed closer to the existing buildings, these excavations may affect the structural integrity of the adjacent existing buildings. Therefore, there is a need to evaluate the response of multistorey building frame (MBF) subjected to nearby series of unsupported open excavations. In the study, a numerical investigation on response of RCC-MBF structure with raft foundation resting on medium dense sand subjected to adjacent unsupported open excavations is performed using a 3D finite element program PLAXIS-3D. The series of open excavation is simulated considering the different geometrical parameters of excavation, such as varying setback distance, and different excavation volumes. As a response, the four parameters are monitored in the columns of the MBF i.e., displacement of the structure in x- and z -directions (i.e., settlement and tilt), and redistributed bending moments and shear forces in the column of MBF. The linear and non-linear analyses are performed to account the effect of constitutive models on the response of the MBF by assigning the Linear–Elastic and Mohr–Coulomb soil constitutive models to the soil respectively. Further, a sensitivity analysis is performed to evaluate the effect of strength and deformation parameters of the soil, and the geometrical parameters of the excavation on the factor of safety of excavation slope. Based on the results, it is observed that Mohr–Coulomb constitutive model can be used to analyse the response of structure subjected to unsupported open excavations. Finally, the effect of different foundation schemes is also analysed in the study.