Experimental and numerical study of the damage process in RC

International audienceIn the present paper, the collapse resistance of reinforced concrete (RC) beam-column sub-assemblages subjected to a middle column removal scenario is investigated on the basis of experimental tests and numerical calculations. For the experimental programme, three one-third scale substructures are designed with two types of longitudinal steel rebar to observe the influence of rebar detailing on the global structural behaviour. The structure under consideration is composed of a two-bay beam, and a middle column lies on two sliding-pin connections to prevent a catenary action mechanism. A digital image correlation (DIC) technique was employed with the experiments to observe the growth of cracks. In addition, numerical simulations using the finite element method (FEM) were also done. The Denoual-Forquin-Hild (DFH) anisotropic damage model is used to simulate the behaviour of the concrete, whereas a plasticity model is used for the steel rebars. The numerical simulations are compared with experimental data in terms of structural yield strength, change in stiffness and crack propagation, and better agreement is observed when a weakening of the concrete due to beam stirrups is taken into account

Numerical modelling of landfill lining system–waste interaction: implications of parameter variability

This article was published in the journal, Geosynthetics International [ICE Publishing / © Thomas Telford Ltd.]. The definitive version is available at: http://www.icevirtuallibrary.com/content/serial/geinNumerical modelling techniques can be used to examine the serviceability limit states of landfill side-slope lining systems in response to waste placement. A study has been conducted in which the variability of significant model input parameters have been investigated within a probabilistic framework using Monte Carlo simulation. Key model parameters are treated as random variables, and the statistical information required to describe their distributions has been derived from a laboratory repeatability testing programme, a literature survey and an expert consultation process. Model outputs include relative shear displacements between lining components, and tensile strains in the geosynthetic layers that occur in response to staged placement of waste against the side slope. It was found that analyses including input parameter variability were able to identify mechanisms influencing liner performance and their probability of occurrence. These mechanisms include large (i.e. ≫100 mm) relative displacements at interfaces that can generate post-peak strengths, and mobilised tensile strains in the geomembrane and geotextile layers. Additionally, it was found that relative displacements at the controlling (i.e. weakest) liner interface are greater for landfills with a steep side slope, for stiffer waste and thicker waste lifts, while tensile strains in the geosynthetic elements are greater for steep side slopes, more compressible waste and thinner waste lifts. Outputs from probabilistic analyses such as that used in this study can guide engineers regarding geometries and materials that could produce waste-settlement-generated serviceability limit state failures, and hence can be used to support more reliable designs

Implications of Masonry Infill and Partition Damage in Performance Perception in Residential Buildings after a Moderate Earthquake

Engineers usually focus on the performance of structural members, whereas the occupants of a residential building are affected mostly by the performance of infill and partition walls in buildings after a moderate earthquake. This often creates controversy and discussion regarding the post-earthquake use of buildings. Seismic rehabilitation codes for existing buildings offer sophisticated measures in rating the seismic performances of structural components, whereas performance measures suggested for infill and other partition walls are crude by comparison. Furthermore, seismic design codes for new buildings totally disregard such disparity, since their force-based approaches are built on single-level performance targets specified implicitly for the entire building under a design level, that is, a rare earthquake. In this paper, performance levels of buildings after an earthquake of moderate intensity are discussed from the viewpoints of engineers and building occupants. Suggestions are made for achieving uniform performance in structures where the seismic forces are resisted by structural members as well as the infills and partition walls coupling with the structural system although the contribution of such walls to seismic resistance and their performance is not usually considered in design