بررسي رفتار برون صفحه ي ديوارهاي بنايي تقويت شده با كامپوزيت هاي سيماني مهندسي شده (ECC)

چكيده انگليسي :

117 Investigation of Out of Plane Behavior of Masonry Wall Retrofitted with Engineered Cementitous Composites ECC Farhad Sehati f sehati@cv iut ac ir June 21 2017 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Mohammad Reza Eftekhar eft@cc iut ac ir AbstractMasonry structures are one of the most vulnerable types of structures in the earthquake due tomassive mass and low material resistance There are many ways to Seismic Rehabilitation ofmasonry structures but the existing methods along with the running time also lead to thedifficulty of implementation Also the common methods impose a massive mass to the structure which itself increases the earthquake lateral forces and it will be necessary to strengthen thefoundation of the structure In the recent decades the use of engineered cementitious composites ECC has become commonplace to increase the bearing capacity and ductility in structuralmembers Composite ECC is High Performance Fiber Reinforced Cementitious Composites HPFRCC which due to its high tensile strength and composite strength it seems that the use ofthese materials in retrofitting masonry walls not only can increase the speed and ease ofimplementation it also has the capability to confront with other methods in terms of costs Thiscomposite is manufactured with different materials combinations the components of that can bechanged according to the designer s requirements Usually the main components of the ECC arecement fly ash fine grain silica sand and optimal amounts of polyvinyl alcohol fibers PVA Due to access restrictions to the fly ash and the cost of silica sand studies in this research haveshown that the use of slag and limestone can be used as a substitute for these two substances inthe ECC mixing plan For this purpose in the first part of this research the effect of replacementof different amounts of slag and fly ash with cement the addition of micro silica and nano silica as well as the effect of fiber type and its amount on the strength and toughness of ECC mortarwere investigated in 21 different mixing plan The results of the experiments on the ECC mixingplans show the addition of slag and fly ash increases the ductility of the flexural samples alongwith reducing the flexural strength Also the addition of Micro Silica and Nano Silica in themixing plan compensates the part of the reduction in flexural strength but it reduces the degree oftoughness of the samples In the second part of this research ECC mortars have been used tostrengthen out of plane of the 7 masonry prisms The parameters for retrofitting these prismsinclude the type and thickness of the mortar the number of reinforced surfaces the number ofgalvanized mesh layer in the tensile surface and the length of the PVA in ECC mortar The resultsshow that the retrofitted an 8 mm thick ECC mortar layer without galvanized mesh cansignificantly increase the bearing capacity and toughness of the compared to non reinforced ones In addition the increase in the bearing capacity and the toughness of the ECC mortar reinforcedspecimens with a galvanized mesh layer compared to the reinforced sand cement mortar with thesame specifications is 300 and 400 percent respectively Also the results of the failure ofreinforced specimens show that the ECC masonry layer adhesion and the surface of the prismlayers are suitably provided and no proper joints are required to provide the proper performanceof the reinforcing mortar Key words Cementitous Composites Flexural Strength Slag Toughness Index Masonry Prism

صحتي، فرهاد

بررسي رفتار برون صفحه ي ديوارهاي بنايي تقويت شده با كامپوزيت هاي سيماني مهندسي شده (ECC)

كامپوزيت هاي سيماني , مقاومت خمشي , سرباره , شاخص طاقت , منشور بنايي