Proposal of procedure for identification of Menétrey–Willam (M-W-3) plasticity surface of homogeneous and hollow masonry units

The article presents the author’s proposal to determine the parameters of the Mentérey–Willam (M-W-3) plasticity surface of the homogeneous masonry elements made of autoclaved aerated concrete (AAC) and vertically hollow calcium-silicate (Ca-Si) masonry units. The uniaxial and triaxial tests of AAC samples in a standard Hoek’s cell was performed while the hollow units made of silicate were tested on a custom-made test stand. By performing statistical analyses, the shape of the meridians of the surface was determined, and then the eccentricity e of the elliptical function was identified

Mechanical Properties of Masonry Walls Made of Calcium Silicate Materials Made in Poland. Part 1. Masonry Properties and Compressive Strength

AbstractThe article presents the results of the compressive strength of wall with thin joints made of 15 types of silicate masonry produced by 12 Polish manufacturers. According to the requirements of PN-EN 772-1:2001 [2] set a normalized compressive strength fb (90 specimens) of masonry units. Investigations of the compressive strength of the wall in made with accordance the requirements of PN-EN 1052-1:2001 [1] (44 specimens) specifying both the characteristic compressive strength fk and the value of K factor as well. Determined the basis strength characteristics of the wall under compression compared to the characteristic proposed in the Polish National Annex to PN EN 1996-1-1 and national annexes of other European countries

Shear and flexural strength of masonry walls made of calcium silicate materials made in Poland

In the article are presented the results of the shear and flexural strength of the masonry specimens with the thin joints made of 15 types of the calcium-silicate masonry units produced by 12 Polish manufacturers. The tests of initial shear strength of the masonry fvko were carried out according to the PN-EN 1052-3 [12] standard (117 specimens). The dependence of the shear strength on the vertical holes percentage were considered as well. The article describes also the results of flexural strength tests (48 specimens) at failure in the plane parallel and perpendicular to the bed joints. The shear and flexural strength is compared with characteristic values proposed in the Polish NA to the PN-EN 1996-1-1 [10] code and national annexes of other European countries. On the basis of performed tests of mechanical parameters of the wall, the authors chose the optimal masonry element, which was used for testing walls subjected to compression, shearing and bending in the plane [16—18]. The results of these studies were partly presented at the international conference WMCAUS-2016 and published in [19

Testing Joints between Walls Made of AAC Masonry Units

Joints between walls are very important for structural analysis of each masonry building at the global and local level. This issue has often been neglected in the case of traditional joints and relatively squat walls. At present, the issue of wall joints is becoming particularly important due to the continuous drive for simplifying structures, introducing new technologies and materials. Eurocode 6 and other standards (American, Canadian, Chinese, and Japanese) recommend inspecting joints between walls, but no detailed procedures have been specified. This paper presents our own tests on joints between walls made of autoclaved aerated concrete (AAC) masonry units. Tests included reference models composed of two wall panels joined perpendicularly with a standard masonry bond (six models), with classic steel and modified connectors (twelve models). The shape and size of test models and the structure of a test stand were determined on the basis of the analysis of the current knowledge, pilot studies and numerical FEM (Finite Element Method) - based analyses. The analyses referred to the morphology and failure mechanism of models. Load-displacement relationships for different types of joints were compared and obtained results were related to results for reference models. The mechanisms of cracking and failure was found to vary, and clear differences in the behaviour and load capacity of each type of joint were observed. The individual working phases of joints were determined and defined, and an empirical approach was proposed for the determination of forces and displacement of wall joints

Identification of Stress States in Compressed Masonry Walls Using a Non-Destructive Technique (NDT)

The structure safety can be assessed, but only indirectly, by identifying material properties, geometry of structures, and values of loads. The complete and comprehensive assessment can be done only after determining internal forces acting inside structures. Ultrasonic extensometry using an acoustoelastic effect (AE) is among the most common non-destructive techniques (NDT) of determining true stresses in structures. Theoretical bases of the method were described in the mid 20th century. They were founded on the correlation between ultrasonic waves and the value and direction of stresses. This method is commonly used to determine stresses mainly in homogeneous materials without any inherent internal defects. This method is rarely applied to porous or composite materials, such as concrete or rock due to a high dispersion of results. Autoclaved aerated concrete (AAC), characterized by high homogeneity and porosity, is the popular material in the construction sector, used to produce masonry units. The discussed tests involved the acoustoelastic effect to determine stresses in the masonry wall made of AAC. This paper presents a widely theoretical background for the AE method, and then describes the author’s own research on AAC divided into two stages. At first, the empirical relationships between compressive stress and velocity of longitudinal ultrasonic wave, including humidity, were determined. In stage II, nine masonry walls were tested in axial compression. Mean compressive stresses in the masonry wall determined with the proposed method were found to produce a satisfactory confidence level up to ca. 50% of failure stresses. Results were significantly understated for stresses of the order of 75% of failure stresses

Joints in walls

W artykule zostały przedstawione wyniki badań własnych połączeń ścian wykonanych z autoklawizowanego betonu komórkowego. Badania przeprowadzono na autorskim, zmodyfikowanym stanowisku badawczym. Łącznie przebadano trzy serie murów po trzy elementy badawcze. Ponadto zaprezentowano ustalenia normowe w zakresie, jakim jest łączenie ścian murowanych, a także przedstawiono podstawowy dostępny na rynku asortyment służący do łączenia ścian.The issue of joints in masonry walls is not well investigated. There is very little experimental research performed on this matter and the test results are hard to be compared because of a lack of unifieded testing schemes and procedures. Hence, the authors performed own tests of joints in walls made of the AAC – the most popular masonry element – with the use of steel connectors

Łączenie ścian. Cz.1

W niniejszym artykule zebrano informacje odnośnie do wymogów normowych, procedur obliczeniowych, zaleceń producentów, a także wyników i wniosków z badań doświadczalnych prowadzonych na świecie w temacie dotyczącym zagadnienia połączeń ścian