Multiscale computational first order homogenization of thick shells for the analysis of out-of-plane loaded masonry walls

This work presents a multiscale method based on computational homogenization for the analysis of general heterogeneous thick shell structures, with special focus on periodic brick-masonry walls. The proposed method is designed for the analysis of shells whose micro-structure is heterogeneous in the in-plane directions, but initially homogeneous in the shell-thickness direction, a structural topology that can be found in single-leaf brick masonry walls. Under this assumption, this work proposes an efficient homogenization scheme where both the macro-scale and the micro-scale are described by the same shell theory. The proposed method is then applied to the analysis of out-of-plane loaded brick-masonry walls, and compared to experimental and micro-modeling results.Peer ReviewedPostprint (author's final draft

Out-of-plane in situ cyclic testing of unreinforced stone masonry walls with distributed loads

The present paper reports an in situ experimental test campaign carried out on existing buildings, in order to investigate the seismic behaviour of traditional masonry walls subject to out-of-plane loads. For the testing proposes, an experimental test setup based on a selfequilibrated scheme was developed and optimized to be applied in situ in two specimens on original and strengthened conditions. The obtained results are presented and carefully discussed namely from the reinforcement solutions’ efficiency point-of-view, as well as compared to previous experimental data obtained for the same type of masonry walls. Additionally, a simplified linearized displacement-based procedure was adapted in order to characterize the nonlinear force-displacement relationship for unreinforced traditional masonry walls and to analytically predict the experimental test results. The confrontation between the experimental and the analytical results are presented and discussed

Evaluation of the in-plane seismic performance of stone masonry walls

Although traditional historic masonry walls can be viewed as unsuitable structures to undergo seismic actions, they, in fact, exist and frequently represent the major structural elements of ancient buildings. Brick unreinforced masonry walls have been widely studied both from experimental and numerical point of view, but scarce experimental information is available for stone masonry walls. Therefore, the present work aims at increasing the insight about the behavior of typical ancient masonry walls under cyclic loading. Besides the strength and stiffness characterization, information about nonlinear deformation capacity is provided in terms of ductility factor and lateral drifts, which represent a step forward for the new concepts of performance based design

Assessment of damage of masonry walls as a function of displacements and repair costs

An overview of a database of cyclic tests of masonry walls is firstly presented in this thesis.\ud The objective of the analysis of the database was to estimate the relationship between the\ud damage and displacements of the masonry walls. A discussion on the typical failure\ud mechanisms of masonry walls and definition of damage states is then presented in the first\ud part of the thesis which addresses also the issue of rehabilitaiton and strengthening of\ud masonry walls by different techniques. The aim of the thesis was to estimate costs of\ud rehabilitiation and strengthening of masonry walls. For this reason six From the base of cyclic\ud tests were selected from the database and analyzed in more details. The cost of reparing the\ud damage in masonry walls was estimated and compared to the costs of construction of new\ud wall. The results have shown that the procedures and reparing costs depend on the damage\ud and the type of masonry. The cost of repairing of damaged walls per unit area is greater than\ud the cost of replacing the wall or the cost of new construction.Therefore it not likely that hollow\ud brick masonry will be reapried in the case of extensive damage

Parametrical study of masonry walls subjected to in-plane loading through numerical modeling

This paper deals with the numerical assessment of the influence of parameters such as pre-compression level, aspect ratio, vertical and horizontal reinforcement ratios and boundary conditions on the lateral strength of masonry walls under in-plane loading. The numerical study is performed through the software DIANA® based on the Finite Element Method. The validation of the numerical model is carried out from a database of available experimental results on masonry walls tested under cyclic lateral loading. Numerical results revealed that boundary conditions play a central role on the lateral behavior of masonry walls under in-plane loading and determine the influence of level of pre-compression as well as the reinforcement ratio on the wall strength. The lateral capacity of walls decreases with the increase of aspect ratio and with the decrease of pre-compression. Vertical steel bars appear to have almost no influence in the shear strength of masonry walls and horizontal reinforcement only increases the lateral strength of masonry walls if the shear response of the walls is determinant for failure, which is directly related to the boundary conditions.This work was partly supported by contract DISWALL - "Development of innovative systems for reinforced masonry walls" - COOP-CT-2005-018120 from the European Commission. The first author was supported by the Programme Alssan, the European Union Programme of High Level Scholarships for Latin America, Scholarship No. E06D100148BR

Retrofitting masonry infill walls with textile reinforced mortar

The vulnerability of unreinforced masonry walls (URM) under seismic events, causing huge loss of money and human lives, has revealed the enormous need for an efficient strengthening material. In this context, the present paper reports the development of a new reinforcing material for masonry walls based on braided fibrous structures. These fibrous materials were developed through braiding of polyester yarns around a core made of either glass or carbon fiber (core reinforced braid) or without any core (simple braid). Masonry walls were fabricated by placing these braided materials on the surface of clay brick walls in a mesh like configuration and covering with a mortar layer. The flexural behavior of developed masonry walls was compared with URM and walls reinforced with more commonly used glass fiber laminates using the same configuration and process

Distinguishing damages from two earthquakes —Archaeoseismology of a Crusader castle (Al-Marqab citadel, Syria)

Damages from two major earthquakes are identified in medieval Al-Marqab citadel (Latin: Margat) in coastal Syria. Built by the Order of St. John (Hospitallers) in the twelfth–thirteenth centuries, the hilltop fortification has masonry walls made with and without mortar, using the opus caementum technology (Roman concrete). V-shaped and U-shaped failures, single-corner and symmetrical corner collapses, and in-plane shifts of ashlar masonry walls are identified and dated by historical and archaeological methods. The azimuth of displacement is NE-SW for the older damages of the Crusader period (A.D. 1170–1285), possibly related to the A.D. 1202 earthquake. A later, NW-SE displacement occurred during the Muslim period (post- 1285). The 1202 earthquake produced at least VIII intensity on the MSK scale at Al-Marqab, which is higher than previously considered

Simulation of retrofitted unreinforced concrete masonry unit walls under blast loading

This paper describes an investigation into the effectiveness of using spray-on nano-particle reinforced polymer and aluminium foam as new types of retrofit material to prevent the breaching and collapse of unreinforced concrete masonry walls subjected to blast over a whole range of dynamic and impulsive regimes. Material models from the LSDYNA material library were used to model the behaviors of each of the materials and its interface for retrofitted and unretrofitted masonry walls. Available test data were used to validate the numerical models. Using the validated LS-DYNA numerical models, the pressure-impulse diagrams for retrofitted concrete masonry walls were constructed. The efficiency of using these retrofits to strengthen the unreinforced concrete masonry unit (CMU) walls under various pressures and impulses was investigated using pressure-impulse diagrams. Comparisons were made to find the most efficient retrofits for masonry walls against blasts

Experimental investigations on dry stone masonry walls

Brick unreinforced masonry walls have been widely studied both from experimental and numerical point of view, but scarce experimental information is available for dry stone masonry walls that constitute the material more frequently used in the construction of ancient historical constructions. Therefore, the present work aims at increasing the insight about the behavior of typical ancient masonry walls under cyclic loading. To attain such goal, different experimental approaches are considered: static cyclic and dynamic tests. Besides the considerable out-of-plane movements of the stones, it was found that flexural response of the walls prevails in both experimental approaches

Experimental analysis of reinforced concrete block masonry walls subjected to in-plane cyclic loading

An innovative system for reinforced concrete masonry walls based on the combination of vertical and horizontal trussed reinforcement is proposed. The mechanical characterization of the seismic behavior of such reinforced masonry walls is based on static cyclic tests carried out on panels with appropriate geometry. The influence of the factors influencing the in-plane cyclic behavior of concrete masonry walls, such as the horizontal reinforcement, precompression, and masonry bond pattern, is discussed. The results are analyzed in terms of failure modes and force versus displacement diagrams, from which the seismic performance is assessed based on the ductility and energy capacity dissipation. The results stressed that the increase on the precompression level leads to a stiffer and more brittle lateral behavior of the masonry walls. The presence of horizontal reinforcement ensures better control and better distribution of cracking, even if only a marginal increase of lateral strength was found in the particular testing program.This work was partly supported by contract DISWALL – “Development of innovative systems for reinforced masonry walls” – COOP-CT-2005-018120 from the European Commission. The first author was supported by the Programme Alβan, the European Union Programme of High Level Scholarships for Latin America, Scholarship nº E06D100148BR