Influence of Structural Redundancy on Fatigue Life of Offshore Wind Turbine Jacket Structures

The concept of structural redundancy is implemented in the fatigue analysis of an offshore wind turbine jacket structure. The analyzed jacket is a real life example. Time domain analyses are performed for the most representative design load case. The uni-directional and multidirectional simulations of the offshore wind turbine system are carried out using a coupling of the aero-elastic code and the finite element code. Fatigue analyses are performed using hot spot stress approach and Miner's rule. Comparative studies show that considering structural redundancy leads to expanded fatigue life of the offshore wind turbine jacket structures. © 2017 ISOPEEC/Horizon202

Experimental investigation of the sliding failure mode in full-scale squat reinforced concrete shear wall specimen

Squat-reinforced concrete shear walls are used as a gravity and lateral load resisting system in structures such as buildings and nuclear power plants. Due to their low aspect ratio, they are prone to shear or sliding failure. A shear wall was subjected to a cyclic test at the new Multi-Axis Sub-Assemblage Testing (MAST) facility at ETH Zurich. The shear to span ratio was 0.51 and a vertical load of 5.61% of the axial capacity of the wall was applied. The wall had a sliding failure, with a peak load capacity of 2760 kN. Digital Image Correlations (DIC) results show how the shear crack developed until sliding started and, from this point on, the majority of the wall deformation originated in the wall-foundation interface. Sliding displacements consisted of more than 50% of the total displacements of the specimen in large-amplitude cycles

Crack Kinematics During the Transition from Shear to Sliding or Crushing Failure in Seismically Loaded Squat Reinforced Concrete Shear Walls

Squat reinforced concrete shear walls are used as gravity and lateral-load-resisting systems in structures such as residential buildings or nuclear power plants. Due to their low aspect ratio, they are prone to failing in shear or sliding. There is uncertainty on which parameters define this failure mode transition, and how to account for this in the design of new buildings or assessment of existing structures. A series of real-scale shear wall tests are being conducted at the multi-axis subassemblage testing (MAST) facility at ETH Zürich to identify the transition between shear and sliding failures. Response analysis of two specimens with the same geometry and reinforcement ratio, but different levels of axial load is presented. Specimen SW01 failed in sliding, whereas Specimen SW02 failed in shear (diagonal compression). Their peak horizontal shear strengths were 2460 kN and 2980 kN, respectively. The evolving kinematics of the cracks developed in both specimens is analyzed using the deformation fields obtained with digital image correlation (DIC) measurements and compared to identify the point of shear-to-sliding and shear-to-compression transitions.ISSN:2366-2557ISSN:2366-256