Violeta Bokan-Bosiljkov

Bio: Violeta Bokan-Bosiljkov is an academic researcher from University of Ljubljana. The author has contributed to research in topics: Grout & Masonry. The author has an hindex of 9, co-authored 15 publications receiving 308 citations.

In situ tests and seismic assessment of a stone-masonry building

Abstract: The injection of grout into multi-leaf stone masonry walls with a sufficient amount of voids can be an effective technique for the seismic strengthening of such walls. In order to evaluate the effectiveness of different types of commercial grouts that fulfilled the adopted criteria, the stone masonry walls of an actual building were strengthened by means of grout injection, using cement and combined cement–lime grouts. The quality and effectiveness of grout injection technique was assessed by non-destructive tests (sonic and radar tests), minor destructive tests (surface and in-depth probing and coring, and the double flat jack test), and destructive test (shear-compressive test), all in situ. Preliminary laboratory tests were also performed on mortar and stone specimens, on the injection grouts, and on cylinders representing the inner core of the strengthened walls. Finally, the seismic resistance of the building was evaluated in non-strengthened and strengthened variants (i.e. after grout injection of the walls with cement or lime–cement grout) by means of non-linear static analysis, using the pushover method. Obtained results show that shear characteristics of the walls (tensile strength and stiffness) depend significantly on the type and properties of the injected grout, i.e. on the grout’s ability to achieve a solid bond between the stones and the leaves including the properties (strength and stiffness) of the grout itself. In the case of the type of masonry under consideration, an adequate level of seismic resistance can be achieved also by using combined cement–lime grouts, although cement grout can provide higher seismic resistance.

In-plane shear performance of masonry panels strengthened with FRP

Abstract: The opportunities provided by the use of Fiber Reinforced Polymers (FRPs) composites for the shear strengthening of tuff masonry structures were assessed on full-scale panels subjected to in-plane shear-compression tests at the ENEL HYDRO S.p.A. laboratory, ITALY. Tuff masonry specimens have been arranged in order to simulate both mechanical and textural properties typical of buildings located in South-Central Italian historical centres. In this paper, the outcomes of the experimental tests are presented. The monotonic shear-compression tests were performed under displacement control and experimental data have provided information about in-plane behaviour of as-built and FRP strengthened tuff masonry walls. Failure modes, shear strength, displacement capacity and post-peak performance are discussed.

Modelling of lime mortar carbonation

Abstract: The carbonation process in lime mortar is influenced by the diffusion of carbon dioxide into the mortar pore system, by the kinetics of the lime carbonation reaction, and by the drying and wetting process in the mortar. All these phenomena depend on the presence of water in the mortar. Water is present in liquid form as well as vapour. Physical models and their mathematical basis are given for the factors influencing carbonation. The mathematical description of the carbonation process in lime mortar completes the information necessary to model the simulation of carbonation in conjunction with the drying process. Simulations at different carbon dioxide concentrations showed a good correlation between experiment and mathematical prediction.ResumeOn donne un aperçu général des différents facteurs qui influencent la carbonatation du mortier à la chaux. On démontre que le contenu d'eau dans le matériau influence la carbonatation aussi bien par un changement de la diffusivité à travers le matériau que par un changement de la réaction entre le gaz carbonique et la chaux. Un modèle mathématique a été développé qui permet la simulation du processus de la carbonatation en tenant compte de l'évolution de séchage du matériau dans son environnement. Des simulations avec des concentrations de gaz carbonique différentes montrent une bonne corrélation entre les expériences et les prédictions mathématiques.

In‐plane strength of unreinforced masonry piers

Abstract: The definition of adequate simplified models to assess the in-plane load-bearing capacity of masonry piers, in terms of both strength and displacement, plays a fundamental role in the seismic verification of masonry buildings. In this paper, a critical review of the most widespread strength criteria present in the literature and codes to interpret the failure modes of piers (rocking, crushing, bed joint sliding or diagonal cracking) are proposed. Models are usually based on an approximate evaluation of the stress state produced by the external forces in a few points/sections and on its assessment with reference to a limit strength domain. The aim of the review is to assess their reliability by discussing the hypotheses, which they are based on (assumed stress states; choice of reference points/sections on which to assess the pier strength; characteristics of the limit strength domain) and to verify the conditions for their proper use in practice, in terms of both stress fields (depending on the geometry of the pier, boundary conditions and applied loads) and types of masonry (i.e. regular brick masonry vs rubble stone masonry). In order to achieve these objectives, parametric nonlinear finite element analyses are performed and different experimental data available in the literature are analysed and compared. Copyright © 2008 John Wiley & Sons, Ltd.