Current Issue : January - March Volume : 2014 Issue Number : 1 Articles : 6 Articles
This paper proposes an analysis procedure able to determine the flexural response of rectangular symmetrically reinforced\r\nconcrete sections subjected to axial load and uniaxial bending.With respect to the usual numerical approaches, based on the fibre\r\ndecompositionmethod, this procedure is based on the use of analytical expressions of the contributions to the equilibriumgiven by\r\nthe longitudinal reinforcement and the concrete region in compression, which depend on the neutral axis depth and the curvature\r\nat each analysis step. The formulation is developed in dimensionless terms, after a preliminary definition of the geometrical and\r\nmechanical parameters involved, so that the results are valid for classes of RC sections.The constitutive laws of the materials include\r\nconfinement effect on the concrete and postyielding behaviour of the steel reinforcement, which can be assumed to be softening\r\nbehaviour for buckled reinforcing bars. The strength and curvature domains at the first yielding of the reinforcement in tension\r\nand at the ultimate state are derived in the form of analytical curves depending on the compression level; therefore, the role of a\r\nsingle parameter on the shape of these curves can easily be deduced. The procedure is validated by comparing some results with\r\nthose numerically obtained by other authors....
The vibration-based structural health monitoring has been traditionally implemented through the deterministic approach that\r\nrelies on a single model to identify model parameters that represent damages. When such approach is applied for truss bridges,\r\ntruss joints are usually modeled as either simple hinges or rigid connections. The former could lead to model uncertainties due to\r\nthe discrepancy between physical configurations and their mathematical models, while the latter could induce model parameter\r\nuncertainties due to difficulty in obtaining accurate model parameters of complex joint details. This paper is to present a new\r\nperspective for addressing uncertainties associated with truss joint configurations in damage identification based on Bayesian\r\nprobabilistic model updating and model class selection. A new sampling method of the transitional Markov chain Monte Carlo is\r\nincorporated with the structure�s finite element model for implementing the approach to damage identification of truss structures.\r\nThis method can not only drawsampleswhich approximate the updated probability distributions of uncertainmodel parameters but\r\nalso provide model evidence that quantify probabilities of uncertain model classes. The proposed probabilistic framework and its\r\napplicability for addressing joint uncertainties are illustrated and examined with an application example. Future research directions\r\nin this field are discussed....
Liquefaction-induced lateral spreading during Tohoku earthquake resulted in significant damage, and disruption of functionality\r\nfor structures and life. The paper aims at reproducing this on-site evidence presenting the state of the art about the most credited\r\nqualitative approach and comparing these methods with numerical computation. In this regard, finite element (FE) simulations are\r\nincreasingly providing a versatile environment in order to assess economical and effective damage. In the study, several systematic\r\nthree-dimensional FE computations have been conducted to numerically evaluate the effects in terms of liquefaction-induced lateral\r\ndeformations. The analysis is performed in correspondence with Urayasu City, where the registered liquefaction consequences on\r\nresidential buildings were wide if compared with the ordinary seismic shake. This study can be used both for post-earthquake\r\nevaluations and for pre-earthquake vulnerability predictions....
This investigation is focused on bending experiment of some prismatic perlite lightweight concrete. In these samples, textile waste\r\nfibers are confined with textile mesh glass fiber and embedded in the central part of cubic lightweight concrete specimens. Bending\r\nexperiments revealed that lightweight concrete panels with a core of textile waste fiber have less density than water and high energy\r\nabsorption and ductility. Furthermore, these composite panels by having appropriate thermal insulation characteristics could be\r\nused for partitioning in the buildings....
A three-dimensional (3D) modeling approach to investigate nonlinear seismic response of a curved and skewed bridge system is\r\nproposed.The approach is applied to a three-span curved and skewed steel girder bridge in the United States. The superstructure is\r\nmodeled using 3D frame elements for the girders, truss elements for the cross-frames, and equivalent frame elements to represent\r\nthe deck. Spherical bearings are modeled with zero-length elements coupled with hysteretic material models. Nonlinear seismic\r\nresponses of the bearings subjected to actual ground motions are examined in various directions. Findings indicate that the bearings\r\nexperience moderate damage for most loading scenarios based on FEMA seismic performance criteria. Further, the bearing\r\nresponses are different for the loading scenarios because of seismic effects caused by interactions between excitation direction\r\nand radius of curvature....
The seismic vulnerability of a historical Basilica church located in Italy is studied by means of limit analysis and nonlinear finite\r\nelement (FE) analysis. Attention is posed to the failure mechanisms involving the fac�¸ade of the church and its interaction with the\r\nlateral walls. In particular, the limit analysis and the nonlinear FE analysis provide an estimate of the load collapse multiplier of the\r\nfailure mechanisms. Results obtained from both approaches are in agreement and can support the selection of possible retrofitting\r\nmeasures to decrease the vulnerability of the church under seismic loads....
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