Usually, soils and structures with different characteristics are closely influenced by each other in civil engineering problems. In addition, structural and geotechnical designs are commonly covered by two different groups with different backgrounds, which often results in communication difficulties as well. The lack of consistency in design may yield to incorrect assumptions and engineering judgments resulting in dangerous or overconservative design. This is seen especially in normal infrastructure construction projects which cannot provide as extensive and multidisciplinary resources as in massive projects.
Ali Vatanshenas believes that it is the delicate blend of both structural and geotechnical perspective that results in the closest estimations with respect to reality. In his doctoral dissertation, he proposed a unified modelling strategy in which both the soil and structure can be modelled sufficiently accurate for practical applications. To reach this goal, the diverse aspects of both the structure and soil must be understood well.
”In my research, I presented these diverse topics in a stepwise and comprehensible manner, chapter by chapter. Then I combined these separated topics to create and verify two comprehensive 3D bridge-soil models,” Vatanshenas explains.
In his thesis, Vatanshenas estimated nonlinearity and maximum shear modulus of plastic soils with low overconsolidation ratio. He also developed and verified new hyperbolic p-y curves suitable for pile-soil, pile group-soil, and wall-soil interactions.
The other main goals of his research were to indicate the importance of structural nonlinearity in soil-structure interaction problems and propose a fully coupled three-dimensional soil-structure interaction modelling technique appropriate for nonlinear static (pushover), linear dynamic (modal), and nonlinear dynamic (time history) analyses applications.
"In my work, I identified the main elements of the interaction problem in two cases between soil and bridge through sensitivity analysis. Through simulation, I was able to find out the nonlinear dynamic response of two instrumented bridges under earthquake loads,” he adds.
Public defence on Friday 24 May
The doctoral dissertation of MSc (Tech) Ali Vatanshenas in the field of civil engineering entitled Nonlinear Soil-structure Interaction of Bridges : Practical Approach Considering Small Strain Behaviour will be publicly examined at the Faculty of Built Environment at Tampere Univeristy at 12 o'clock on Friday 24 May 2024 at City centre campus, in auditorium K103 in Linna building (Kalevantie 5, Tampere).
The Opponent will be the Professor Murat Dicleli and the Custos will be Industry Professor Anssi Laaksonen from Tampere University.