Finite element implementation of a model to estimate the permanent strain of cyclically-loaded soil

Babaoğlu, Muhittin
In vast majority of geotechnical structures such as monopile or strip foundation, which are subjected to repeated loading, long-term resilience of the structures is directly related with the behavior of granular materials subjected to cyclic loading. Repeatedly loaded structure distributes stress to soil that surrounds the structure. When granular materials are exposed to cyclic loading, plastic strain occurs despite the applied stress is less than plastic yield, which results to residual settlement. This thesis provides a simplified numerical method implementation in finite element method (FEM) that estimates deformation of granular materials exposed to high numbers of cyclic loading for intricate 3D systems. Using explicit approach, which determines permanent strain for a specific number of loading cycles by means of empirical formulas in one solution step, this method eliminates error accumulation due to every FEM steps. Required experimental tests to obtain model parameters are elaborated. This model is utilized for the simulation of constant-amplitude cyclic loaded monopile embedded in soil. Comparison of numerical results with experimental data indicates great agreement and considerable improvement over commonly used existed methods. This study offers suggestions for prospective researches in the view of proposed method, which focus on 3D modeling of cyclic loaded granular materials. Furthermore, varying-amplitude cyclic loaded monopile is also modeled as an extension of the proposed model with strain-hardening approach.


Finite element analysis and practical modeling of reinforced concrete multi-bin circular silos
Balkaya, C; Kalkan, E; Yuksel, SB (2006-05-01)
Stress resultants in overlapping wall regions (intersection walls) of multi-bin circular silos require a significant computational effort to determine forces due to structural continuity. This paper presents a practical equivalent beam model for computing design forces along the silo walls when subjected to various internal and interstice loadings. The equivalent beam model of intersection wall was developed based on the effective length concept, and verified in a comprehensive series of finite element (FE)...
Metaheuristic based backcalculation of rock mass parameters around tunnels
Gedik, Görkem; Pekcan, Onur; Department of Civil Engineering (2018)
Due to uncertainities in the ground conditions and the complexity of soil-structure interactions, the determination of accurate ground parameters, which are not only used in tunnel construction but in the design of all underground structures, have a great significance in having structures that are cost-efficient. Backcalculation methods which rely not only on laborotory and field tests but also on field monitoring and field data provide real structure conditions and therefore it is gaining popularity in geo...
Finite element modeling of block shear failure in coped steel beams
Topkaya, Cem (2007-04-01)
Block shear is a potential failure mode that is encountered in the connection regions of coped steel beams. Limited experimental studies completed so far have shown that the block shear failure in coped steel beams is a complex phenomenon, which is highly dependent on the number of bolt lines. In this paper, the use of the finite element method in predicting the block shear failure load was studied by making comparisons with experimental findings. The effects of numerical modeling details on load capacity p...
Models for Pore Pressure Response of Low Plastic Fines Subjected to Repeated Loads
SAĞLAM, SELMAN; Bakir, Sadik (2018-01-01)
Cyclic pore pressure response of low plastic fines is examined with regard to factors influencing overall behavior of such soils under repeated loads. A model for pore pressure generation under repeated loads and another model for relationship between cyclic pore pressure and straining are proposed. The models are developed in consideration of an extended database generated through a comprehensive literature review. The models are evaluated based on the comparisons between predicted and measured pore pressu...
Stress Scaling Factors for Seismic Soil Liquefaction Engineering Problems: A Performance-Based Approach
Çetin, Kemal Önder; Bilge, Habib Tolga (2013-06-19)
Most of the widely used seismic soil liquefaction triggering methods propose cyclic resistance ratio (CRR) values valid at the reference normal effective stress (sigma(v,0)') of one atmosphere and zero static shear stress (tau(st,0)) states. Then, a series of correction factors are applied on this reference CRR, for the purpose of assessing the variability due to normal effective and static shear stress states (i.e. K-sigma and K-alpha corrections) acting on the horizontal plane. In the literature, a number...
Citation Formats
M. Babaoğlu, “Finite element implementation of a model to estimate the permanent strain of cyclically-loaded soil,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Civil Engineering., Middle East Technical University, 2020.