Civil Engineering / İnşaat Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/13
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Article Citation - WoS: 37Citation - Scopus: 35Behaviour of Buried Continuous Pipelines Crossing Strike-Slip Faults: Experimental and Numerical Study(Elsevier, 2021) Demirci, Hasan Emre; Karaman, Mustafa; Bhattacharya, SubhamoyThe paper examines the behaviour of buried continuous pipelines crossing strike-slip faults using experimental and numerical modelling. A newly developed experiment setup is presented along with the derivation of relevant scaling laws and non-dimensional terms governing global response of continuous pipelines to strike-slip faulting. Four model tests are carried out to understand the performance of the pipelines and the results are presented through the derived non-dimensional framework. Three-dimensional (3D) Finite Element (FE) model is also undertaken to simulate buried continuous pipelines crossing strike-slip faults and is calibrated against the model test results and a field case record for validation and verification. A parametric study is also carried out to better understand the parameters influencing the response of buried continuous pipelines to strike-slip faults and to also investigate the effects of pipe end conditions on their behaviour. API 5 L X70 steel pipe with 490 MPa of yield strength was used in the numerical parametric study. Two different scenarios based on fault crossing angle of the pipe (beta) were considered in the parametric study: (a) pipelines in tension and bending; (b) pipelines in compression and bending. The experimental and numerical results show that the longitudinal pipe strains under strike-slip faulting are strongly dependent on six parameters: (a) normalized fault displacements (represented by delta/D where delta is the fault displacement and D is the pipe diameter which is also an indication of soil strain in the mobilised zone); (b) ratio of pipe diameter to wall thickness (D/t); (c) fault crossing angle of the pipe (beta); (d) relative soil-pipe stiffness (kD4/EI); (e) ratio of burial depth to pipe diameter (H/D) and (f) pipe end conditions. Finally, practical implications of the study are discussed.Article Citation - WoS: 10Citation - Scopus: 11Transport Capacity Models for Unsteady and Non-Equilibrium Sediment Transport in Alluvial Channels(Elsevier Ltd., 2012) Tayfur, Gökmen; Singh, Vijay P.This study investigates transport capacity models based on different dominant variables-shear stress, stream power, unit stream power, flow discharge, flow velocity, and energy slope - in a model of unsteady and non-equilibrium sediment transport in alluvial channels. The model simulates fully coupled system of water flow, suspended sediment, and bed load sediment transport processes in two-layer system of water flow phase and movable bed. The model employs conservation of mass equation for the water in both the layers; suspended sediment in the water flow phase; sediment in the movable bed layer; and the momentum equation for the water flow in the flow phase. The system is closed by relating the sediment flux in the movable bed layer to the sediment concentration in the same layer by employing the kinematic wave theory. Using the sediment transport capacity expression with different dominant variables, a series of numerical experiments are carried out for unsteady and non-equilibrium sediment transport. The results seem theoretically reasonable for hypothetical cases. The model is calibrated and validated using different experimental data sets. The calibrated value for the transport capacity model's exponent (ki) is found to be 1.50, 1.65, 0.24, 0.56, 4.80, and 0.22 for shear stress, stream power, unit stream power, discharge, velocity, and slope approaches, respectively. The numerical investigation results show that transport capacity model based on any dominant variable can be employed for modelling unsteady and non-equilibrium sediment transport.