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An elastic-plastic interface model for fracture of quasi brittle materials
No full textTECHICAL REPORT - Università degli Studi di Bresci
Cyclic Analyses of Reinforced Concrete Masonry Panels Using a Force-Based Frame Element
No full textThis paper presents the calibration of a frame element that can be used to model the flexural as well as the shear behavior of reinforced masonry panels subjected to monotonic and cyclic loads. The element can be used in the equivalent frame method to analyze masonry wall systems, and is based on a force-based Timoshenko beam element formulation that combines a fiber-section model with a phenomenological nonlinear shear law. The element was originally applied to the analysis of reinforced concrete frames, and has been recently extended to unreinforced masonry structures. Well-established constitutive laws are used for masonry and steel reinforcement. The constitutive law for shear requires special attention in order to correctly predict the shear force-deformation response of masonry walls, accounting for the presence of shear reinforcement. A procedure to calibrate the parameters of the shear law is presented. The effectiveness, accuracy, and simplicity of the force-based Timoshenko frame element and the calibration method are validated by results of experimental tests. Even though the element is general and can model any reinforced masonry panel, the applications of this paper focus on panels made of hollow concrete blocks
Empirical formulation of the out-of-plane resistance of infilled frames
Get PDFThe assessment of out-of-plane resistance of infilled frames is an issue of primary importance, in fact, post-earthquake damage observations have shown that infills subject to combined in-plane and out-of-plane inertial forces may fail out-of-plane. This collapse mode results particularly dangerous for the safety of people in the proximity area of a building subject to earthquake loads. Therefore, the possibility to perform accurate safety evaluations is fundamental to prevent this kind of failures. Available expressions for the evaluation of out-of-plane resistance of infilled frames are based on too restricted or too large datasets of experimental investigations. Because of this, such expressions are many times conflicting, showing good reliability in some cases and less in others. In order to fill this gap, this paper proposes a new data-driven empirical expression estimating OOP resistance of infilled frames. This expression is based on hybrid data-set, merging experimental data with data from numerical simulations obtained from a refined FE micro-model. The new expression has the advantage to take into account both the aspect ratio of the infilled frame, the influence of vertical loads and the mode of application of the OOP load. Validation tests are finally carried out against experimental and numerical specimens
A REINFORCED CONCRETE MODEL FOR ANALYZING FLEXURAL AND SHEAR BEHAVIOR OF R/C BEAM-COLUMNS
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A REINFORCED CONCRETE MODEL FOR ANALYZING FLEXURAL AND SHEAR BEHAVIOR OF R/C BEAM-COLUMNS
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