ارائه مدل جديد رفتاري براي واحدهاي آجر كاري معمول ساختمان هاي بنايي تاريخي ايران

چكيده انگليسي :

The New Model for Common Brickwork Units Behavior in Historical Masonry Structures of Iran Parvaneh Ansary p ansary@cv iut ac ir August 18 2010 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Dr Amir Mehdi Halabian Mahdi@cc iut ac ir Abstract Masonry is the oldest building material that still wide use in present buildings Also thousands of brick made historical buildings in Iran are counted as the important legacy of Iran The need to preserve and protect these historical structures has seen the emergence of researches directed toward the analytical modelling of fracture in masonry Masonry is a composite material made of units brick blocks etc and mortar Important new developments in masonry materials and applications occurred in the last decades but the techniques to assemble bricks and mortar are the same as the ones developed thousand years ago The fracturing mechanism in masonry is a complex phenomenon due to two brittle materials with distinct material properties The mechanical behavior of brickwork is strongly affected by the behavior of mortar joints Mortar joints are the plans of weakness of masonry especially in old buildings due to the weathering and agedness Therefore the orientation of mortar joints affects the fracture pattern of brickwork and causes different types of crack pattern in brickwork settings Accordingly the analysis of historical buildings aimed at structure assessment and restoration and other masonry buildings demands an adequate understanding of the mechanical behaviour of these different types of brickwork setting and accurate data consist of elastic and inelastic parameters This study presents the results of numerical modelling of common types of brickwork behavior existed in Iran s brick built monuments Since the possibility of derivation an accurate yield criteria is probably costly and time consuming there is a higher willingness of using simple plasticity material model for practical problems Forming of the placement of bricks and mortar bound have a large influence in implementation of load bearing elements in masonry structures It is noted that masonry exhibits distinct directional properties because of the influence of the mortar joints An accurate analysis of masonry structures in a macro modeling or composite perspective requires a material description for all stress states Its failure cannot therefore be defined simply in terms of a criterion based on the principal stresses at any point The influence of a third variable must also be considered Generally masonry modeling on computers has been performed with three different main approaches via detailed Micro Modelling Simplified Micro Modelling and Macro Modelling In this study the computations of simplified micro modeling simulated tests of brickwork panels are performed using 3DEC program based on Distinct Element Method DEM Analysis that used in this software is in form of dynamic semi static process with Discrete Distinct Element method and with use of frequency in contact force displacement law and Newton second law In the DEM modelling Mohr Coulomb failure surface with a tension cut off is chosen as a constitutive law for both blocks and joints with zero thickness representing mortar bonds Using these elastic plastic parameters for different parts the behaviors of different brickwork setting constructions subjected to the semi static loads are evaluated This investigation is aimed for loading of different types of brickwork and achievement of the new model for common brickwork units behavior This study involved axial and biaxial compression and tension tests with the form of plane stress situations on square panels of brickwork with varying principal stress ratios and bed joint orientations third variable for two brickwork types Running Bond The study forms part of a series of models aimed at developing a complete 1 2 failure surface for all principal stress com

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ارائه مدل جديد رفتاري براي واحدهاي آجر كاري معمول ساختمان هاي بنايي تاريخي ايران

سطح شكست , روش اجزاء محدود , چيدمان آجر كاري , تنش هاي دو محوري , درزهاي خوابيده