- Seismic Analysis of Soil-Structure Interaction.
- Soil Dynamics and Geotechnical Earthquake Engineering.
- Seismic Performance Design of Buildings.
- Numerical Modeling and Simulation.
- Deep Excavation and Earth Retaining Structures.
- Use of Precision Instruments in Excavation Projects.
- Building Damage Assessment for a Building Adjacent to Excavation.
Yeganeh, N & Fatahi, B 2019, 'Effects of choice of soil constitutive model on seismic performance of moment-resisting frames experiencing foundation rocking subjected to near-field earthquakes', Soil Dynamics and Earthquake Engineering, vol. 121, pp. 442-459.View/Download from: Publisher's site
© 2019 Elsevier Ltd The current study investigated the extent to which the choice of the soil constitutive models can impact the predicted seismic performance of a 20-story reinforced concrete moment-resisting building with a mat foundation considering the Seismic Soil-Structure Interaction (SSSI). Since the soil, in general, is the weakest material, involved in the commonplace geotechnical engineering projects, a soil constitutive model would be able to rule the dynamic response of the system. In this research, the hardening plasticity-based soil constitutive model, named 'hyperbolic hardening with hysteretic damping' in conjunction with the two simple, conventional soil models, namely, the isotropic elastic with hysteretic damping model, and elastic-perfectly plastic Mohr-Coulomb with hysteretic damping model, were invoked in the three-dimensional coupled soil-structure numerical simulations using FLAC3D software. The direct method of analysis was used for analyzing the soil-foundation-structure system in one single step without a need to separately analyze each part of the domain. The cherry-picked earthquake excitations, viz, the 1999 Chi-Chi (Taiwan), and 2011 Kohriyama (Japan), were scaled by means of the widely-used response spectrum matching method as per the design response spectrum of a strong rock. The plastic moment concept was employed so as to assign the elastic-perfectly plastic model to the superstructure and its foundation. Additionally, the strain-compatible shear modulus and damping dependency on the cyclic shear strain were considered via the programmed hysteretic damping algorithm. The numerical predictions included the response spectra at the seismic bedrock and ground surface, base shear forces, shear force distributions along the building height, maximum and permanent foundation displacements, and foundation rocking, plus the flooring lateral deflections and inter-story drifts. The life safety limits for the transient and residual total in...
Yeganeh, N & Fatahi, B 2018, 'Seasonal Effects on Seismic Performance of High Rise Buildings Considering Soil-Structure Interaction', 16th European Conference on Earthquake Engineering, Thessaloniki, Greece.View/Download from: UTS OPUS
The Seismic Soil-Structure Interaction (SSSI), which is a tangled phenomenon, is concerned with the shear waves in preference to the longitudinal waves on account of a prevalent greater energy content in the former. The need for the high rise buildings in the megalopolises results in the paramountcy of the seismic soil-foundation-building interaction analysis in order to achieve the reliable predictions and mayhap curtail the severe damage and probable partial or total collapse of the superstructures. The seasonal effects could influence the soil moisture content particularly in the vadose zone near the surface, exacerbated by the climate change effects, inducing more frequent floods and drought. Wherefore, a soil-structure model was evaluated in this study, subjected to the soil moisture variations in the vadose zone, by utilizing the 3D finite difference modeling technique through the fully nonlinear dynamic analysis in the time domain considering SSSI during the 1994 Northridge earthquake. In particular, the objective was probing the possible effects of the selected degree of saturation (Sr) values, i.e., 5%, 17.5%, 60%, and 100%, for the noncohesive soil, named 'Glacier Way Silt', in conjunction with the small-strain shear moduli on the seismic performance and its corresponding damage of a 20-story reinforced concrete moment-resisting building frame. It is of note that the said values of Sr were employed for the common 4-m zone of influence in Australia, being a sequel of the natural and artificial wetting-drying cycles. Get to the point, it was concluded that the season, in which an earthquake befalls, is stark prominent insomuch as it is potent to impact the extend of the damage in a superstructure.
Yeganeh, N, Fatahi, B & Terzaghi, S 2017, 'Effects of Shear Wave Velocity Profile of Soil on Seismic Response of High Rise Buildings', International Conference of the International Association for Computer Methods and Advances in Geomechanics, International Association for Computer Methods and Advances in Geomechanics (IACMAG), Wuhan, China.View/Download from: UTS OPUS
There is, nowadays, a conspicuous demand for the high rise buildings in the high-density dwellings of the urban areas; in consequence, harnessing the whiz-bang numerical simulations plus conducting the rigorous experimental studies so as to design and construct such prodigious structures would be essential. Thus, the appropriate parameters for modeling the structure and the soil medium in the Soil-Structure Interaction (SSI) system should be selected. The soil-structure interaction is referred to the process in which the soil response is told on by the structure motion whilst the latter is affected by the soil motion. The current research zeroed in on the soil shear wave velocity and its influence on the superstructure performance. Invoking the weighted average shear wave velocity with the aim of calculating the soil shear modulus, which is closely related to the strength and deformation characteristics of the soil, has been a hotly debated issue since the aforesaid parameter was posited by a plethora of codes and regulations to obtain the soil site classification required for the earthquake design. To that end, the numerical model, having two assorted profiles associated with the shear wave velocity, namely, the in situ non-uniform profile (Case A) and the equivalent uniform profile (Case B), was built by means of FLAC3D, capable of analyzing the complex interaction issues via the direct method whereby the entire system of the structure-foundation-soil is modeled and analyzed in one single step. To put it in a nutshell, employing the weighted average shear wave velocity for the entire soil mass in parsing of the 3D seismic soil-structure interaction problems would be accused for ending up with somewhat unreliable results, e.g., underestimated drift ratio and building deformation, which might be the culprit of the damage to the building and possibly the death of the residents residing in the earthquake-prone zones.