The Influence of Compressive Stress on the Load-Bearing Capacity of Masonry Subjected to Vertical Displacements

3rd World Multidisciplinary Civil Engineering, Architecture, Urban Planning Symposium

土木建筑工程;文学

Piekarczyk, Adam^1

Silesian University of Technology, Civil Engineering Faculty, Department of Building Structures, Akademicka 5, Gliwice

44-100, Poland^1

关键词: Autoclaved aerated concrete;    Clay brick walls;    Compressive loads;    Hydraulic cylinders;    Load-bearing capacity;    Solid clay bricks;    Vertical compressive stress;    Vertical displacements;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/471/5/052017/pdf
DOI  :  10.1088/1757-899X/471/5/052017

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

The paper describes the results of tests of masonry wallets made of solid clay bricks with joints of normal thickness (10 specimens) and filled vertical joints and autoclaved aerated concrete (AAC) blocks with thin joints and unfilled vertical joints (5 specimens). The specimens made of clay bricks were 1290 mm wide, 1415 mm high and 250 mm thick, while the specimens made of AAC blocks had the width of 1250 mm, the height of 1510 mm and the thickness of 240 mm. The tests were carried out in a specially designed steel test stand witch which the masonry specimens were monolithised. The force applied along the vertical edge of the specimens and causing the vertical displacements was carried out by means of hydraulic cylinder. The masonry specimens were tested without participation of vertical compressive stresses perpendicular to the bed joints σc or the tests were carried out after initial compression, which induced stress in the wall with mean values from 0.3 to 1.5 N/mm2 for solid clay brick specimens and 0.9 N/mm2 in walls made of AAC blocks. The compressive loads were implemented using four pairs of tensioned steel tendons equipped with springs to compensate the influence of masonry displacements. The deformation angles of masonry were also investigated. Deformation angles were calculated based on changes in the length of the system of measuring bases placed on both surfaces of the specimens. The compressive stresses σc influenced the values of the mean shear stress τcr,σ (force inducing vertical displacements divided by the area of the vertical cross-section of the specimen) at which the first oblique crack appeared. The τcr,σ stress was always greater than the stress τcr,0 at which the first crack occurred in the specimens tested without compression. The ratio τcr,σ/τcr,0 for solid clay brick specimens ranged from 1.38 to 2.24, depending on the stress value σc and 2.18 for masonry made of AAC blocks. Compressive stresses also influenced the increase of the masonry deformation angles at the moment of the first cracking θ cr,σ in relation to the deformation angle θ cr,0 of the specimens tested without compression. This effect was proportional to the increase of τcr so that the mean modulus of deformation was about 1630 N/mm2 for clay brick walls. In the case of specimens made of AAC blocks a ratio of stress to angles of deformation Gcr equal to 631 N/mm2 when the tests were not accompanied by compressive stresses (σc = 0) and 461 N/mm2 when σc = 0,90 N/mm2. Similar results were obtained in the case of the effect of the compressive stress σc on the increase of shear stress τu and the accompanying deformation angles λ u at the maximum force inducing vertical displacements of masonry specimens obtained in tests.