A Stochastic Multi-scale Approach for Numerical Modeling of Complex Materials - Application to Uniaxial Cyclic Response of Concrete

In complex materials, numerous intertwined phenomena underlie the overall response at macroscale. These phenomena can pertain to different engineering fields (mechanical , chemical, electrical), occur at different scales, can appear as uncertain, and are nonlinear. Interacting with complex materials thus calls for developing nonlinear computational approaches where multi-scale techniques that grasp key phenomena at the relevant scale need to be mingled with stochastic methods accounting for uncertainties. In this chapter, we develop such a computational approach for modeling the mechanical response of a representative volume of concrete in uniaxial cyclic loading. A mesoscale is defined such that it represents an equivalent heterogeneous medium: nonlinear local response is modeled in the framework of Thermodynamics with Internal Variables; spatial variability of the local response is represented by correlated random vector fields generated with the Spectral Representation Method. Macroscale response is recovered through standard ho-mogenization procedure from Micromechanics and shows salient features of the uniaxial cyclic response of concrete that are not explicitly modeled at mesoscale.Comment: Computational Methods for Solids and Fluids, 41, Springer International Publishing, pp.123-160, 2016, Computational Methods in Applied Sciences, 978-3-319-27994-

A Study of the Historical Construction Technology of Bell Towers in Cyprus

This paper aims to present the historical construction technology of churches’ bell towers in Cyprus, starting with the initiation of their use and addressing the development of their distinctive morphology adapting and mixing various architectural styles. Traditional bell towers are tall and slender unreinforced masonry structures that are known to be particularly vulnerable to earthquake actions encountered in seismogenic regions, such as Cyprus. Therefore, iron and wood elements with high tensile capacities were commonly utilized in Cypriot bell towers in the form of ties. In particular, the bell tower of Saint John’s church in Psevdas village was constructed using such technology and is an example case studied in more detail in the present work. This tower suffered a partial collapse during an earthquake on May 12th, 2016 and underwent restoration within the next year. Based on the knowledge gathered from the case of the damaged tower and the visual inspection of other bell towers in Cyprus, the use of timber and iron ties in these masonry structures is deemed to be essential for their protection from seismic actions