IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 _______________________________________________________________________________________ Volume: 04 Issue: 08 | August-2015, Available @ http://www.ijret.org 268 DYNAMIC ANALYSIS OF STEEL TUBE STRUCTURE WITH BRACING SYSTEMS Dhanapalagoud Patil 1 , Naveena M P 2 1 Student, Structural Engineering, MVJ College of Engg, Karnataka, India 2 Assistant Professor, Structural Engineering, MVJ College of Engg, Karnataka, India Abstract Nowadays, competition towards rise of tall steel structures made certain factors are compulsory like serviceability and comfort of human relating to lateral loads caused by wind or earthquake. Earthquake is dangerous to the living beings in terms of its effects on manmade structures. Structures like tall buildings are built to resist gravity loads. However many tall buildings are not so resistant in lateral loads due to earthquake so need an improvement in resisting lateral loads. So there are many structural systems which resist lateral loads by varying orientation, addition of different structural systems. Like steel tubular structural system is considered and compared for their results against lateral forces and also by providing mega bracing system and diagrid bracing system. In this dissertation work, four structural systems are considered in which one is framed structure and rest are tubular system with addition of different bracing systems as mega bracing and diagrid bracing system. For the purpose 45 storey steel structure with rectangular plan of dimension 44mx24m uniform throughout the height is considered and analyzed for gravity and lateral loads using ETABS software. Its intention is to obtain the functioning characteristics like displacements, storey shear, time period, frequency, peak displacement and peak acceleration in both x and y direction to get most economical structure in all ways. Results shows that the steel tubular structure with mega bracing system performance is much better than the framed structure, tubular and tubular structure with diagrid bracing system. Keywords: Steel Tube Structure, Mega Bracing, Diagrid Bracing, Dynamic Analysis, ETABS, Time and History Analysis. --------------------------------------------------------------------***---------------------------------------------------------------------- 1. INTRODUCTION Structures are being used from the antiquated times, where as the change in human's life made tall structures more adoptable for their economic wellbeing, requirement for their most elevated eminence in the general public for their legendry. Now days the development of urban communities by relocation of individuals from their local to lovely urban areas made more thickness more than a territory as a result ascent of tall structures have been happened. However science, technology, architect have also influencing the ascent of tall buildings. In tall structures the tallness is comparative term. Exact definition of tall structures cannot be applied worldwide. From structural engineering point of view tall structures must resist gravity and also lateral loads. The competition towards rise of tall structures have made significant about the design of building to resist against lateral load. The geometry of the building also not the fundamental criteria to design the tall and slender building yet the drift of the building is responsible for stresses developed in the building. Various structural systems are raised for stabilization of tall building against lateral loads like shear frames, belt truss with out-rigged system, frames with bracings, super columns, shear wall, wall-frame, braced tube system, outrigger system, tubular system, mega bracing. Recently, the Diagrid – Diagonal Grid – structural system is widely used. 1.1 Scope and Objective.  An attempt has been made to Analyze the fallowing tall structure using conventional software ETABS. 1) Frame structure, 2) Tube Structure, 3) Tube Structure with mega bracings, 4) Tube Structure with Diagrid bracings.  Numbers of stories considered are 45 stories, each of height 4m for all models.  To investigate and study by applying different available structural systems. For minimizing the deflection under lateral loading.  Structures are analyzed using equivalent static analysis and dynamic analysis for particular soil and zone.  Responses of different structural systems are studied in terms of displacements, story drifts.  Conclusions are drawn based on the observations and better structural system is found out with this study. 1.2 Concept of Tubular System  The main ideology of tubular structure is to resist horizontal load by arranging structural element efficiently.  In this system many elements contribute to resist loads like slabs columns beams mainly spandrel beams and columns at the periphery of the building resist lateral load.