One of the most important aspects of designing dimension-stone cladding involves determining the configuration, size and spacing of the panels and anchorages that will affix the stone panels to the underlying building substrate. A laboratory study was carried out in order to determine the mechanical and physical behaviour of medium size granite panels. A significant number of samples were subjected to transverse pull out tests in accordance with EN 13364:2001, so that the breaking load at the dowel hole could be determined. The material strength was evaluated by determining flexural strength under a concentrated load (in accordance with EN 12372) and a under constant moment (in accordance with EN 13161). The flexural resistance and dowel force anchorage data were then processed and used to build a semi-empirical model for determining the value of the forces obtained. Finite-element computer analyses of the stress states induced in the stone panels by the dowels were also carried out. Recommendations are made for design formulae and the procedure to be used in the prediction of design resistance in granite stone cladding panels showing similar behaviour.

This paper describes epoxy resins by means of electrical impedance spectroscopy (EIS) and the mathematical tool of fractional calculus (FC). Two stages are considered: first, the EIS is used for testing the samples and, second, the measured data are approximated using integer and fractional order models. The FC-based modelling describes the epoxy resins using a small number of parameters that reflect their main characteristics. The EIS data gathered for the epoxies samples are compared with those of different adhesives and sealants by means of a hierarchical clustering algorithm that unravels the relationships between the distinct materials. This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.

This paper analyses undercut anchorage technology, in particular its behaviour and performance as a fixing system for dimension stone cladding of rainscreen façades. Based on a number of mechanical tests using various types of Portuguese stone – three igneous, two sedimentary and one metamorphic – a study was carried out to investigate the relationship between the flexural strength and breaking load of specific and very common stone types. Several physical and mechanical characterisation tests and 130 pull-out tests with 6 and 8 mm cone bolt threads were performed to determine the pull-out load failure on six different stone types: three granite, two limestone and one marble. Finite-element stress analyses were carried out, and the test results were the basis for calibrating a simple formula that can be used to estimate the stone's breaking load at the undercut anchorage. Stress concentration factors are proposed to take into account the undercut drill hole geometry and the specific properties of each type of stone. Stone specimens from the same batches were subject to pull-out force tests using dowel anchorages, whose values were then compared with the breaking load of undercut anchorages. Results are discussed and conclusions are drawn based on tensile stress values by comparing the test results, the finite-element method and the proposed semi-empirical formulations for the same breaking load.

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Today's thin stone veneers must be designed to resist, besides their self-weight, high wind pressures and induced seismic forces. They must accommodate hygrometric differential movement, deflection, vibration and creep, etc. When available, code requirements do not provide an accurate or realistic safety factor for the specific type of anchor and or stone used in a project. Global safety factors that are recommended by stone industry associations are imprecise and used as rules of thumb. Limit state design has replaced the older concept of allowable stress design in most forms of civil engineering. As a result, all modern buildings are designed in accordance with a code which is based on limit state theory for all man-made materials, yet there is an astonishing nonexistence of ′natural stone′. In this paper partial factors of safety are proposed depending on the types and on the coefficients of variation of the distributions of resistances. Their values are determined using structural reliability analysis for the load and resistance factor design format according to Eurocode 1990. Aging and stone resistance decay is outside the scope of the article, yet some guidance is provided on the influence of stone durability on stone cladding performance. An application example is used to illustrate both methods, and conclusions are drawn.