ارائه روش ناحيه نزديك و مدل هاي نيمه تحليلي براي تحليل اندر كنش سازه و خاك و پاسخ حداكثر سازه هاي مجاور هم در زلزله

چكيده انگليسي :

Presentation of the Near Field Method and Semi Analytical Models for Analysis of Soil Structure Interaction and the Maximum Responses of Adjacent Structures during Earthquakes Mehdi Ghandil m ghandil@cv iut ac ir Date of Submission 2011 06 18 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Farhad Behnamfar Mahmood Vafaeianfarhad@cc iut ac irAbstractIn design of low rise structures the effects of soil structure interaction are often ignored However theseeffects are considerable for heavy structures such as skyscrapers or multi level highway structures Theexistence of this interaction phenomenon can also be extended to the adjacent buildings For example in anarea congested with many nearby tall buildings to account for the proximity effects of adjacent buildingswill become critical Previous few studies conducted in this area were limited to 2D finite element plain strain models While assuming plain strain for foundation soil may be valid for a building structure withlimited dimensions in plan this assumption could be erroneous In this thesis the effects of soil structure interaction and structural adjacency on the response of structuresare studied Also a simple and effective method for soil modeling in the analysis of soil structure interactionand adjacent structures is presented 3D models of 5 10 15 and 30 Story building structures on strip mattand group piles are used The foundation soils are assumed to be 25 m layered sand and 45 m layered clay The site classification for both of these soils is type III corresponding to the Iranian Code of Practice forSeismic Resistant Design of Buildings Dynamic analyses are performed under seven horizontal componentsof actual earthquakes For structural modeling beam element is used for frames and piles Shell elements are used for rigiddiaphragm and pile caps Solid 3D element with 8 nodes is selected for direct finite element modeling ofsoils Structural elements are assumed to behave linearly in general and nonlinearly in critical cases Toaccount for soil nonlinearities the equivalent linear approach is assumed for soil behaviour This method iseffective fast and sufficiently accurate for analysis of large scale soil media Also in critical states plasticmodeling is done for the near field soil Results show that the soil structure interaction SSI increases thelateral displacement response of moderate tall and very tall structures up to 24 in roof and 98 in firstStory of structures and decreases the lateral displacement of short structures 12 in average For shearforce responses of structures in stories SSI decreases the response in all cases up to 30 in the first Storyand 50 in roof levels In structural adjacency cases results show that the adjacency increases the lateraldisplacements of stories up to 80 in first Story for shorter structure and 30 in first Story for tallerstructure and decreases the shear forces of stories up to 75 in roof for shorter structure and 20 in rooffor taller structure It is expected that for two adjacent structures as they are closer the interaction responseof the structures is higher and for deep site cases the variation of response of the structures are moreextensive Finally for presentation of applicable and useful results from this study several semi analyticalformulations are developed Keywords Soil Structure Interaction Structural Adjacency Equivalent Linear Method Near FieldMethod Story Lateral Displacement Story Shear Force

قنديل، مهدي

ارائه روش ناحيه نزديك و مدل هاي نيمه تحليلي براي تحليل اندر كنش سازه و خاك و پاسخ حداكثر سازه هاي مجاور هم در زلزله

مجاورت سازه ها , روش خطي شده معادل , روش ناحيه نزديك , جابجايي طبقات , برش طبقات