Sharif Digital Repository

Due to unusual response of structures of buildings with irregularity in their architecture to dynamic excitations, to have a comprehensive knowledge of their behavior during earthquakes is of utmost importance. Building irregularities are in general divided into two major categories, namely Irregularity in Plane and Irregularity in Elevation, and one of the forms of the latter is where there is a split in the levels of the building. In this work, through a series of case studies, the effects of P- phenomenon on the behavior of steel split-level building structures were studied. 5, 10 and 15 story buildings with 5 and 6 bays, and level splitting of 30, 60, 90, 120 and 150 cm were studied. All... 

Due to restrictions on connecting beams to columns in steel structures when moment-resisting connections in two perpendicular directions are employed, the use of ordinary wide-flange sections or fabricated boxes becomes impractical. Application of Cruciform sections, especially when fabricated from two split-I sections (IPE sections) seems to be a reasonable solution to this problem. In this study, using Finite Elements Method and a commercial FEM software, the nonlinear behaviour of a number of cruciform columns, already tested by others, were modeled numerically. After reaching results in acceptable agreement with those of the tests, potentially suitable sections for fabrication of... 

In this work the response modification factor (RMF), behaviour factor, of two-dimensional regular and split-level steel braced frames was worked out and presented. A total number of 840 frames with various number of stories, spans, braced spans and span lengths were studied. Frames were loaded based on ASCE 7-10 and designed in accordance with AISC 360-10. Static nonlinear analysis and Uang method were used for obtaining the RMFs of the studied frames. The effect of split-level irregularity and parameters such as number of stories on the RMF were worked out and are presented in this thesis. Linear regression was used to develop formulae for RMFs of regular and split-level braced frames.... 

In this study, the behavior of a new innovative bracing system under cyclic loading and according to AISC code is investigated. An Ideal bracing system, in addition to having sufficient stiffness, should have a suitable ductility. Also, in order to prevent inelastic behavior of other structural members, braces, in addition to possessing high architectural adaptivity, must be able to contain the damage within itself and behave like a fuse. Three specimens with different sections, IPE100, HEA100 and 2UNP100, were designed and tested. The results of these tests represent an elastic- (approximately) perfectly plastic behavior of the brace if an appropriate section is used. Moreover, this bracing... 

Various types of tanks are used to store a variety of liquids, drinking water, chemicals, petrochemicals, and liquefied natural gas. Of these, one type is ‘elevated tank’ which is used to provide the required pressure for the water distribution systems rather than satisfying the water demand. Satisfactory performance of tanks during strong ground motions is crucial for modern facilities. Theoritical and experimental investigations of the dynamic behaviour of liquid storage tanks are conducted to seek possible improvments in the design of such tanks to resist earthquakes. The behaviour and performance of a new elevated tank was studied in this work. It was carried out through finite elements... 

Observation made after previous earthquakes revealed that irregular structures had shown unfavourable performance compared to their regular counterparts. In general, structural irregularities are classified into two categories, “irregularity in plan,” and “irregularity in elevation (height).” In order to investigate the effects of irregularities on the “response modification factor,” three types of 3-D steel structures were studied, namely type 1: regular ones, type 2: split-level ones (having irregularity in elevation), and type 3: irregular in plan as a result of having eccentricities of 5%, 10%, and 20% between the centers of mass and rigidity. All the studied frames were initially loaded... 

In this thesis, the shearing behaviour of a semi-rigid connection is studied experimentally. Due to high shear rigidity of existing connections, even those which demonstrate semi-rigid behaviour under bending, their shear characteristics have not been studied yet. Regarding the concerned semi-rigid connection, it was necessary to examine its behaviour under shear, experimentally. Altogether, five series of specimens were tested under shear loading. Tests on two of these series, due to fabrication deficiencies, twice had to be halted before reaching the final stage—each time the specimens were sent to the fabricator to fix the improper welds. The results of these tests clearly show the high... 

The lateral force & its control has always been a great concern to structural designers. Based on the project’s location, this force can be either earthquake or wind force. In our country, Iran, the earthquake force is usually the dominant one. Of the most important differences between these two kinds of forces, we may point out the cyclic characteristics and nature of earthquake forces. One can choose different strategies to face the earthquake force including the use of dampers. Dampers exist in vast varieties of different categories which we will briefly explain in this thesis. Dampers can be used on their own or in combination with other lateral force resistance systems like bracings or...