Experimental And Numerical Analysis Of Pakistan Brick Masonry Structure

The Kashmir earthquake (Oct. 2005), causing over 79000 deaths, was one of the worst disasters in the history of Pakistan and of the Indian subcontinent. The vast majority of buildings destroyed in the struck area are masonry buildings. Being in general the low quality of non-engineered masonry buildings the main cause of collapse and damage. The effective measures should be taken to improve the quality of masonry construction for earthquake resistance. In this background, NWFP University in Peshawar entrust the Institute of Engineering Mechanicsm, China Earthquake Administration to conduct necessary quasi-static tests for selected masonry components. This thesis is the summary and analysis of these experiments. This thesis studies the quality of the resistance of brick masonry component which is constructed in the Pakistan traditional method under shearing lode, and under compressive load. In one aspect this study enforce our impression of the failure process of brick masonry component which is constructed in Pakistan traditional method, in another aspect we can check a lot of theories. On the basis of conclusion and analysis of experiment results, this thesis use two kinds of numerical methods to simulated the failure process of masonry component under cyclic loading. This thesis could supply valuable experiment results for the study of the earthquake resistance of the Pakistan traditional masonry structures, also could supply the reference for the numerical analysis study of our country's old masonry structures. From the study ,we can get these results:1. With reference of a lot of documents, thesis writes some things about the study conditions of masonry structures in our country and in other countries at first, and then, thesis expatiate the developing process of masonry building and the methods of masonry study.2. This thesis studies the non-linear failure process of masonry components constructed in Pakistan traditional method on the basis of Simulating Pseudostatic experiment.3. Experiment results imply that, because the difference of deformation ability, the collapse of masonry component under compressive loading normal to bed joints is caused by the tensile stress in the bricks.4. From the experiment results, we can find out that the compressive stress is the main-factor which influences the resistive ability of shear loading of masonry component, at the same time thesis also indicates that the main deformation of a masonry component under some loading come from mortar joints between bricks.5. with the experiment results, we can find out that the failure of a masonry component under the combination of shear loading and compressive loading is not purely caused by the tensile stress in the mortar which overpass the resistive ability of tensile stress of the mortar, and is not also purely caused by the friction stress between brick and mortar which overpass the resistive ability of friction stress ability of the masonry component. The real condition is that the failure process of a masonry component under shear and compressive loading is the changing process of the two conditions which mentioned above. The failure process of a masonry component under the combination of shear loading and compressive loading could be divided into three steps. (1) At this step. specimen have out crack or have small cracks. The first crack is caused by the tensile stress which overpass resistive ability of tensile stress of the mortar between bricks. (2) At this step, specimen have some cracks but these bricks not united as one big crack. The crack is caused by the reason that the mortar which is not destroyed is not strong enough under tensile stress and reason that the friction-press-resisted strength is not big enough between mortar which was destroyed and bricks. (3) At this step, cracks meet each and are united as one big crack. The failure of specimen is caused by the friction stress between brick and mortar which overpass the resistive ability of friction stress ability of the masonry component.6. On the basis of the experiment results and the conclusion of other person's work in this field, thesis uses two kinds of numerical methods-separating method and collective method-separately to simulate the non-linear failure process of masonry wall. The numerical simulating results imply that, the collective method is easy, but the simulated results became more and more inaccurate with the development of the cracks in the specimen, the separating method is difficult and need a lot time to calculate, but the simulated results are near to test results.