Sharif Digital Repository

In this thesis, the use of jet-engine for oil well fire fighting which is a latest in kind is described and analyzed. For this purpose, more familiarization with this system and some knowledge’s such as hydrodynamics characteristic of nominated area, traditional ways of fire fighting in region, different types of jet engines available type of offshore vessels, type of flame and their characteristic are required, which after studying and analyzing above fields in details, the use of turbojet motors and barge has been chosen for the case to obtain optimum specification os this turbojet motors and required dimensions of barge Some information about oil well shuch as, fluid output, speed rate... 

This paper investigates the behavior of the Y-shaped bracing system. Because of the special type of eccentricity in this system, the behavior of the frame is strongly dependent on the geometrical changes of the braces. So that even in the elastic region, it shows the geometrically nonlinear behavior. The amount of eccentricity is very effective on the nonlinear behavior of the frame. Also the ratio of cross sections of the bracing members has a very important impact on the expected performance of the frame. The results show that this system tolerates large displacements, and can act like a base isolation system. Firstly, using a two-dimensional accurate modeling related to the geometrical... 

A particular kind of concentric bracing system composed of three members arranged in y-shaped geometry is examined in this thesis. The non-straight diagonal strut of this off-centre bracing causes eccentricity to the system and is connected to the frame corner through a third member. Providing adequate openings in braced bays accompanied by improved energy dissipation are resulted in positive attitude toward using y-bracing frame as a lateral load resisting system. However, lacking of specific design codes could be problematic for engineers. To overcome this incompetency, seismic performance factors including the response modification coefficient, the system overstrength factor, and... 

Finding suitable locations for installing conventional concentric bracings such as X and V, without interfering with building architecture and its openings, is a routine challenge in building design. One of the less known forms of concentric bracings which can be used to solve this issue, is the y-shaped bracing composed of three braces. In the current thesis, results of analytical studies, computer modeling and experimental tests are presented to extend the knowledge of structural behavior of y-bracings. As the first step, effective buckling lengths of braces with rigid connections were found from equilibrium equations incorporating the effect of axial force on rotational stiffness of...