Mechanism Of Shrinkage On Infilled Masonry Wall In Frame Structure And Its Cracking Control

Drying shrinkage-induced cracking is common failure mode in infilled masonry wall in frame structure. Shrinkage crack occurred reduce the applicability, durability and effect of heat preservation and energy-saving of building. So, analysis of mechanism of drying shrinkage of infilled masonry wall in frame structure, and research on cracking control measures effectively is especially important.A comprehensive method including field investigation, laboratory test, theoretical analysis, and finite element simulation has been used in research work: Site investigation of crack in masonry infilled wall in frame structure. Analysis of mechanism drying Shrinkage of masonry material used in wall; Experimental study on shrinkage of brick; Discrete finite element simulation of cracking of masonry infilled wall in frame structure; Research of cracking control measures in infilled masonry wall in frame structure; Cracking control in masonry infilled wall with opening in frame structure.The main result of this work can be drawn as follows:1. Improved Young’s formula is deduced considering the influence of the pressure difference between inside and outside of the interface. Research results can be more reasonable interpretation of the physical phenomenon which wetting angle change with the change of pressure difference between inside and outside of the interface.2. During the process of the water evaporation, deduced the formula of strain variation in the radial of the uniform pore size and reduced aperture averaging capillary structure, the results proved that the wall of capillary structure expansion. The theory of non smooth capillary tube tension is proposed. Formula of radial stress relaxation and axial compression of non smooth capillary tube is deduced during the process of the water evaporation.3. The discrete finite element model of masonry infilled wall in frame structure was constructed. The influence of the wall length, frame stiffness, joint tensile strength, boundary conditions, construction measures, dry shrinkage rate on cracking and crack width on different parts of infilled wall has been quantitatively analyzed.4. Effect of crack control measures in infilled masonry wall in frame structure has been quantitatively analyzed based on The discrete finite element model and results of drying shrinkage test on brick. The limit of length based on he crack control of masonry infilled wall in frame structure is provided.