Sharif Digital Repository

These days steel frames are among the most widespread structural systems, and apart from this, tendency for using slender members in these frames, shows the need for study of effects of axial force and in other words stability of the structure and its members. When secondary effects due to axial gravity forces which results in lateral displacement of the structure come in action, they will reduce strength significantly; as a consequent ductility demand with raise. If this decreased strength exceeds the existing redundant strength, displacements will increase significantly and cause instability of the structure and its collapse. AISC 360-10 has introduced 3 methods for analyzing stability of... 

This paper puts forward an innovative energy dissipation system in steel moment resisting frames, and presents its experimental and numerical studies. In the proposed system, a replaceable beam with a smaller cross-section than that of the main beam is placed at the mid span of the beam designed to act as a shear fuse. This shifts the location of the plastic hinging from the ends of the beam to the middle since the shear fuse yields in shear prior to the flexural yielding of the main beam. This system eliminates the need to comply with the rigorous limitation on the beam span-to-depth ratio that is proposed by seismic design codes to ensure the formation of plastic hinges at the two ends of... 

Nowadays, proper design and retrofitting of structures against natural and manmade disasters, is among the main concerns of researchers and designers in order to reduce financial and human costs. Extensive research has been carried out on the structures resistance against earthquake up to now. Although, the vast amount of research has resulted various regulations and guidelines, there is still a long way ahead to achieve the desirable results. Due to high sensitivity of the steel to temperature variations, fire exposure is more destructive for steel structures compared with the concrete ones. The performance of an intermediate three-storey steel moment frame with 4 spans was studied in this... 

Study of former earthquakes damages reveals that irregular structures are more susceptive to failure than regular ones. Irregular structures are classified into two categories, namely those with irregularity in elevation and the ones with irregularity in plan. Besides, one of the crucial parameters in working out the earthquake’s equivalent static load is response modification coefficient (R). Based on the type of seismic lateral force-resisting system, this parameter can have various values. In this research, using nonlinear static analysis, the response modification coefficient of a great number of 3-D steel frames of 5, 7 and 9 m spans and having 1 to 10 stories with various... 

Abstract- Due to vulnerability of metallic structures to fire, to have an advance estimate of the behaviour and performance of the structure during fire, can greatly assist the designers to make preparations and take precautionary measures to prevent excessive damage to the building. The study of the behaviour of a structure at high temperatures can be divided into two parts, that of its members, and that of its joints. The survey of the literature reveals that most of the previous work concentrated on the former, and it seems that there has not been much work on the latter. The objective of this project was to study the behaviour of structural joints at elevated temperatures, in general,... 

Today using cold-formed steel elements as members of light-weight structures is more common especially in low-rise residential and industrial buildings. Due to Thin-walled plates used to make these sections, members of the frame are prone to premature local buckling and they don’t show good ductility under seismic loadings. Beacause of these reasons, using cold-formed steel elements in moment frames has become a big challenge for scientists. Lots of numerical and experimental models have been presented.
In this study, we investigated the behavior of a beam-column moment connection, consists of two back to back channel sections with curved flanges, using a plate passing through the... 

Life-cycle cost analysis (LCCA) is an assessment tool for studying the performance of systems in many fields of engineering. In earthquake engineering LCCA demands the calculation of the cost components that are related to the performance of the structure in multiple earthquake hazard levels. In this work structural performance required for LCC estimation is achieved by performing ET analysis, while Incremental static and dynamic analyses are two procedures that can be traditionally used for estimating the seismic capacity of structural systems. In this method the structure is subjected to an increasing accelerogram which its time represents ascending earthquake intensities corresponding to... 

Shape memory alloys (SMAs) are nowadays promising candidates for seismic engineering appli-cations due to their ability to undergo reversible deformations and to dissipate energy when subjected to cyclic loading. This thesis presents a numerical study of the torsional performance of structures equipped with end-plates connections using SMA as well as high strength steel bolts and identifies the required locations of SMA connections in a number of typical steel mo-ment resisting frames to improve their seismic torsional performance in terms of maximum inter-story drift and residual deformations. In this regard, 6 and 9-story steel structures were considered with eccentricity ratios of 0%,... 

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 mostbuildings,wallpanels andarchitecturalreasonsaremanufactured. Butbecause of thecomplexity ofthe issueandthe lack oflogicaland yetsimpleanalytical modelof thecombinedfillerpanels and its effectonthe structural behaviorlargelyaffectedcarefulconsiderationin analysisofbuildingstructuresbeneglected. This assumptionmay reducethe accuracy oftheestimation oflateral stiffness, strengthand ductilityofthestructureloading. Althoughthe2800 Iranian Standard stipulated that thewallsshouldbe consideredin loading and design but anywhere the code don’t talk about method, and details needs toshouldbe taken intoconsideration. Among theimportantissuestobe mentioned, effect of infills in creation of soft... 

In this dissertation, a vast number of 2D steel IMFs (Intermediate Moment Frames) with various number of stories and bays, each having one soft storey, of various intensities (ordinary soft storey & extreme soft storey), were studied. The frames were loaded according to ASCE SEI-7-16 and were designed based on AISC-360-10. In order to make a storey softer than others, its height was increased with respect to those of other ones. The dynamic ‘nonlinear spectral analysis,’ and two different static approaches, namely those of ‘ASCE/SEI-7-90’ and ‘ASCE/SEI-7-16,’ were used to study the frames. Comparison of the results obtained from the three aforementioned methods, one dynamic and two static...