1,721,092 research outputs found
“Moment redistribution limits for steel-concrete composite beams accounting for ULS and SLS requirements.”
No full textNumerical evaluation of long-term behaviour for continuous steel-concrete composite beams
No full textIn the paper, results obtained by using a new finite element model for the study of steel-concrete composite beams are presented. Creep, shrinkage, cracking in tensile zone for
concrete and non linear elastic deformable connection are considered. By means of numerical and experimental comparisons it is shown how this numerical approach provides accurate results. The most important parameters that influence the response are analysed and same
effects of viscous phenomena on serviceability and ultimate limit states are presented
A finite element model for collapse and long-term analysis of steel-concrete composite beams
No full textThis paper concerns the development of a numerical procedure for studying steel–concrete composite beams with regard to both the collapse analysis and long-term behavior at the serviceability limit state. The interaction among different parameters that affect the beam response, i.e., connection flexibility, rheological phenomena of concrete (creep and shrinkage), and nonlinear behavior of component materials (concrete cracking, nonlinear behavior of connection, yield of reinforcement, and yield of steel beam), is adequately
considered by a uniaxial finite element model. The creep of concrete is taken into account using Maxwell’s generalized rheological model
through a step-by-step time increment procedure. The nonlinear behavior of component materials is considered through a new nonlinear iterative procedure called the ‘‘modified secant stiffness method,’’ particularly effective for this type of problem. Some comparisons with experimental results demonstrate the reliability of the proposed formulation and its capability to predict the real structural behavior in both short-term tests under the collapse load and long-term tests under the service load
A macro-model with nonlinear springs for seismic analysis of URM buildings
Full text linkSeismic assessment of existing unreinforced masonry buildings represents a current challenge in structural engineering. Many historical masonry buildings in earthquake regions were not designed to withstand seismic loading, thus these structures often do not meet the basic safety requirements recommended by current seismic codes and need to be strengthened considering the results from realistic structural analysis. This paper presents an efficient modelling strategy for representing the nonlinear response of unreinforced masonry components under in-plane cyclic loading which can be used for practical and accurate seismic assessment of masonry buildings. According to the proposed strategy, a generic masonry perforated walls is modelled using an equivalent frame approach, where each masonry component is described utilising multi-spring nonlinear elements connected by rigid links. When modelling piers and spandrels, nonlinear springs are placed at the two ends of the masonry element for describing the flexural behaviour, and in the middle for representing the response in shear. Specific hysteretic rules allowing for degradation of stiffness and strength are then used for modelling the member response under cyclic loading. The accuracy and the significant potential of the proposed modelling approach are shown in several numerical examples, including comparisons against experimental results and the nonlinear dynamic analysis of a building structure
“Time-dependent behaviour of the ‘Tecnaria’ stud connector for timber-concrete composite structures“
No full text"Moment redistribution in continuous steel-concrete composite beams with compact cross-section"
No full textThe paper investigates the design of continuous steel-concrete composite beams with compact cross section using the elastic analysis with limited redistribution. The permissible moment redistribution which satisfies the requirements of the ultimate limit state
(collapse) and serviceability limit state (crack width in the concrete slab) was computed. An advanced finite element program accounting
for all mechanical nonlinearities and time-dependent phenomena (creep and shrinkage of concrete) was used. An extensive parametric analysis aimed to determine the influence of several geometrical parameters on the permissible moment redistribution was carried out on propped cantilevers and fixed-end beams. The analyzed parameters include the shape of the steel profile, the ratio between the depths of
concrete slab and steel beam, the steel to concrete area ratio, and the reinforcement percentage of the concrete slab. The analysis was
limited to compact steel sections (AISC 360-05) or class 1 steel sections (Eurocode 3) and low ductility reinforcing steel (elongation at maximum load epsilonru=2.5%). The moment redistribution domain which satisfies the rotation compatibility in the critical sections, due to the attainment of the rupture of the reinforcement or the local buckling of the steel profile, and the control of cracking (<0.3 mm) in service
was evaluated and compared with the limits recommended by current codes of practice. A proposal for the allowable moment redistribution
domain according to the limits of the study was given
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