101,895 research outputs found
Design and modelling of a novel damage-free steel column base
No full textColumn bases are fundamental components of a steel frame. However their design has not yet received appropriate attention. Conventional steel column bases cannot be easily repaired if damaged and exhibit difficult-to-predict and simulate stiffness, strength and hysteretic behaviour. This paper proposes a novel demountable and fully repairable column base for resilient steel buildings. The new column base isolates damage in easy-to-replace structural elements with the goal of minimizing repair time and disruption of the building service in the aftermath of a strong earthquake. Moreover, it can be easily constructed and deconstructed to enable sustainable steel frame designs. It provides significant flexibility in the design, with rotational stiffness and moment resistance that can be independently tuned. It has self-centering capability for reducing residual drifts. The paper presents design rules, an analytical hysteretic model and a 3D finite element model for the new column base
Design rules, experimental evaluation, and fracture models for high-strength and stainless-steel hourglass shape energy dissipation devices
No full textSteel yielding hysteretic devices provide a reliable way to increase the energy dissipation capacity of structures under seismic loading. Steel cylindrical pins with hourglass shape bending parts (called web hourglass shape pins - WHPs) have been recently used as the energy dissipation system of posttensioned connections for self-centering steel moment-resisting frames. This work evaluates the cyclic behavior of WHPs made of high-strength steel and two grades of stainless steel, i.e., austenitic grade 304 and duplex. Design rules for WHPs are established using principles of mechanics. Twenty-six tests using different cyclic loading protocols and different WHP geometries were conducted. The tests showed that the WHPs have stable hysteretic behavior and high fracture capacity. WHPs made of duplex stainless steel have the most favorable and predictable performance for seismic applications. Two micromechanics-based fracture models, i.e., the void growth model and the stress-modified critical strain model, were calibrated and their parameters are provided for high-strength steel and the two types of stainless steel. The ability of the cyclic void growth model to predict fracture in WHPs under cyclic loading is also evaluated.</p
Environmental benefits arising from demountable steel-concrete composite floor systems in buildings
Get PDFUltralow Cycle Fatigue Tests and Fracture Prediction Models for Duplex Stainless-Steel Devices of High Seismic Performance Braced Frames
Get PDFThis paper presents ultralow cycle fatigue tests and the calibration of different fracture models for duplex stainless-steel devices of high seismic performance braced frames. Two different geometries of the devices were tested in full scale under 14 cyclic loading protocols up to fracture. The imposed protocols consisted of standard, constant-amplitude, and randomly generated loading histories. The test results show that the devices have stable hysteresis, high postyield stiffness, and large energy-dissipation and fracture capacities. Following the tests, two micromechanics-based models, i.e., the cyclic void growth model and the built-in ABAQUS ductile fracture model, were calibrated using monotonic and cyclic tests on circumferentially notched coupons and complementary finite-element simulations. In addition, Coffin-Manson-like relationships were fitted to the results of the constant-amplitude tests of the devices, and the Palmgren-Miner’s rule was used to predict fracture of the devices under the randomly generated loading protocols. Comparisons of the experimental and numerical results show that the calibrated models can predict ductile fracture of the devices due to ultralow cycle fatigue with acceptable accuracy
Seismic analyses of composite frames with partial-strength connections and partial interaction
No full textCyclic tests and finite element analyses of exterior semi-rigid composite beam-to-column sub-assemblages
No full textInfluence of partial-strength joints and partial interaction on the seismic behavior of a composite frame: experimental tests and numerical analyses
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Experimental and numerical study on the cyclic behavior of semi-rigid exterior composite joints
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