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A study of endurance time method in the analysis of elastic moment frames under three-directional seismic loading
, Article Asian Journal of Civil Engineering ; Volume 11, Issue 5 , 2010 , Pages 543-562 ; 15630854 (ISSN) ; Estekanchi, H ; Sharif University of Technology
2010
Abstract
Endurance Time (ET) method is a time history based analysis procedure that applies special intensifying acceleration functions for estimating the seismic performance of structures at different excitation levels in each single analysis. One of the extensions of the ET method is in the seismic assessment of buildings considering multi-component excitation. In this paper, a procedure for three-directional seismic analysis of buildings is proposed and application of this method to several steel moment frames is investigated. Several Steel Moment Frames were designed according to INBC Code. These Frames were analyzed under ET acceleration functions in horizontal and vertical directions...
Nonlinear seismic assessment of steel moment frames under bidirectional loading via endurance time method
, Article Structural Design of Tall and Special Buildings ; Vol. 23, issue. 6 , April , 2014 , p. 442-462 ; ISSN: 15417794 ; Estekanchi, H. E ; Sharif University of Technology
2014
Abstract
In this paper, considering horizontal components of seismic excitation, an algorithm for the nonlinear multi-component analysis of building structures by the Endurance Time (ET) method is proposed, and results of the ET method for various steel moment frames with one to seven stories are verified by comparing with the results from Nonlinear Time History Analysis with use of two different sets of ground motions. In addition, several parameters such as eccentricities and irregularities in structure, rotational and lateral stiffness, effect of hysteresis type and ductility have been considered for sensitivity analysis on results, obtained by ET method. Results show that on the basis of...
Endurance time method for multi-component analysis of steel elastic moment frames
, Article Scientia Iranica ; Volume 18, Issue 2 A , 2011 , Pages 139-149 ; 10263098 (ISSN) ; Estekanchi, H. E ; Sharif University of Technology
2011
Abstract
The Endurance Time (ET) method is a time history-based dynamic analysis procedure which uses special intensifying acceleration functions for evaluation of the seismic response of structures. One of the potential applications of the ET method is in the three-dimensional analysis of buildings under multidirectional excitations. In this paper, considering horizontal components of excitation, an algorithm for the multi-component analysis of building structures by the ET method is proposed, and results of the ET method for various steel moment frames with 1 to 7 stories are compared with results from time history analysis with real earthquakes. Results show that based on recommendations of...
Compatibility of the endurance time method with codified seismic analysis approaches on three-dimensional analysis of steel frames
, Article Structural Design of Tall and Special Buildings ; Volume 22, Issue 2 , 2013 , Pages 144-164 ; 15417794 (ISSN) ; Estekanchi, H. E ; Sharif University of Technology
2013
Abstract
The endurance time (ET) method is a time history-based dynamic pushover analysis procedure that utilizes special intensifying acceleration functions for estimating the seismic performance of structures at different excitation levels. One of the potential applications of the ET method is in the three-dimensional analysis of buildings considering multidirectional excitation. In this paper, a procedure for multi-component analysis by the ET method has been developed. Several steel moment frames with heights from 9.6 to 48 m were designed according to the Iranian National Building Code. By applying the proposed algorithm for three-dimensional analysis of structures by the ET method, these frames...
Three Dimensional Non-Linear Seismic Analyses of Buildings, Using Endurance Time Method
, Ph.D. Dissertation Sharif University of Technology ; Esmaeil Pourestekanchi, Homayun (Supervisor)
Abstract
Endurance Time Method (ET) is a type of dynamic pushover procedure in which the structure is analyzed under special series of accelerograms, called ET acceleration Functions (ETAF) and the response of structure is sketched versus time until the collapse state. With evaluating response curve and the time which damage in structure reach the expected value, the final assessment of structure can be made. In this dissertation, the application of ET method for Non-linear 3 dimensional seismic analysis of steel moment frames under earthquake multicomponent excitation is investigated. For this purpose, various patterns of ET loading are investigated and the most appropriate algorithm in...
Characteristics of second generation endurance time acceleration functions
, Article Scientia Iranica ; Volume 17, Issue 1 A , 2010 , Pages 53-61 ; 10263098 (ISSN) ; Estekanchi, H. E ; Vafai, A ; Sharif University of Technology
2010
Abstract
The Endurance Time (ET) method is a time-history based dynamic pushover procedure in which structures are subjected to specially designed, intensifying accelerograms, and their seismic performance is judged based on the time duration needed to satisfy the required design objective. Second generation refers to ET acceleration functions that are generated by application of optimization techniques in order to produce response spectra compliant linearly intensifying accelerograms. In this paper, the major characteristics of a set of second generation ET acceleration functions (ETA20a01-3) are investigated. The template response spectra of this set of ET acceleration functions corresponds to the...
Application of the endurance time method in seismic analysis of concrete gravity dams
, Article Scientia Iranica ; Volume 18, Issue 3 A , June , 2011 , Pages 326-337 ; 10263098 (ISSN) ; Estekanchi, H. E ; Vafai, A ; Ghaemian, M ; Sharif University of Technology
2011
Abstract
In this paper, application of the Endurance Time (ET) method in seismic analysis of concrete gravity dams has been investigated. The ET method is based on time history analysis of structures, subjected to specially designed intensifying acceleration functions. It is expected that by developing its application in analysis of concrete dams, useful information on the seismic behavior of such dams at various excitation intensities can be obtained. Results from linear analysis of Folsom and Koyna dams under real earthquakes and ET acceleration functions have been compared. It is shown that the ET method can predict the response of concrete gravity dams to individual earthquakes with reasonable...
Studying the Behaviour and Performance of an Innovative Floating Offshore Platform
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
The objective of this project is to study the behaviour and performance of an innotative floating offshore platform. Such Platform not only can be used for exploring oil from offshore fields, but for creating artificial islands, where land is in short supply. Due to its specific and, at the same time, simple geometry (symmetric), its fabrication does ont involve much complexity. Studies carried out on this platform include the investigation into its structural behaviour under gravitational (including self weight) and bouyancy forces. Studied cases include a number of platforms with different (geometrical) sizes and under 3 various bouyancy conditions (percentage), namely 1) 50% of the height...
The Study of The Behaviour of Steel Structures with Semi-Rigid Connections Subject to Fire
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
Fire is one the events which threatens the very existence of every building, residential, office, industrial or else. However, this threat is more serious with regard to buildings with steel structures. Steel, despite its many advantages over other structural materials, such as having high strength to weight ratio, ductility, toughness and resilience, has the disadvantage of rapidly losing its strength at elevated temperatures, i.e. in fire. Therefore, it is the responsibility of the designer to make the serious decision of whether to use steel, concrete, timber, or other materials for the structure of the building to be designed. Observations made during full-scale fire tests as well as...
Study of the P-^ Effects on the Behavior of Split-Level Steel Structures
, M.Sc. Thesis Sharif University of Technology ; Khansari, Vahid (Supervisor)
Abstract
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...
Three Dimensional Simulation of Morphology of Nanodroplets Near and on Structured Substrates
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
Mesoscopic hydrodynamic equations are solved employing a VOF based method to investigate the equilibrium shape of nanodroplets positioned over various topographic geometries of the supporting substrate for three-dimensional systems. By taking into account liquid-liquid and liquid-solid interactions a complex distribution for inter-molecular forces over the substrates (the disjoining pressure) is observed. In this research we show that motion of nanodroplets not only caused by contact angle difference in drplets two sides, but also depend on disjoining pressure parameters.Geometries with increasing complexities, from wedges to three dimensional edges and wedges, were explored with the main...
Investigating the Seismic Behaviour of Split-Level Building Structures
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
Observations made after previous earthquakes have shown the crucial role of irregularities in initiating damage in buildings with irregularity, either in Plan or in Elevation. Since in existing Building Codes, there is no provision for the distribution of the Equivalent Static Loads for such buildings, designers have no option but to resort to Dynamic Analysis. In this work, the seismic behaviour of a group of two-dimensional steel building structures with irregularity in elevation, namely Split-Level buildings, was studied. The studied structures consist of a series of 5- and 15-storey frames having two parts with splitting distance of 150 cm. Both, moment-resisting and braced frames were...
Numerical Study of Base Plates under Biaxial Bending
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
Base plates as the connecting components of steel structures to their foundations, have a crucial role in the behavior of these structures. In order to limit the thickness of base plates hence their cost within reasonable values, various types of attachments (stiffeners) are normally added to them. In this project 6 different configurations, Models, for the base plate and its attachments were considered and studied through finite element analysis. Each Model was studied under the combination of biaxial moments and a range of compressive loads including 0, 0.05 P/Py, 0.10 P/Py and 0.15 P/Py, where Py is the plastic load of the column. The moment-rotation curves of all models under various...
Numerical Modeling of the Behavior of Base Plates with Various Degrees of Rigidity Under Cyclic Loads
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Co-Advisor)
Abstract
Due to the important role of base plates, both in transferring forces from the structure to the foundation, and also in transferring vibrations from soil to the structure, it is necessary to have sufficient knowledge on their behaviour and performance under monotonic and cyclic loading regimes. In fact, the behaviour of the supports of any structure cannot be identified without identifying the behaviour of its base plates. Numerous configurations with/without various types of attachments have been proposed and used for base plates. In this work, altogether six commonly-used types of base plates were studied and their behaviour under monotonic and cyclic loadings was obtained using commercial...
Homogeneous Charge Compression Ignition (HCCI) Combustion Simulation using a Multi-Zone Chemical kinetics Model
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor)
Abstract
In recent years, the idea of Homogenous charge compression ignition (HCCI) engines has been in the center of attention as a new generation of internal combustion engines. Intense decrease in pollutant emission rate like NOx, low fuel consumption and high thermal efficiency are the main reasons of why these engines are in center of attention, however, some drawbacks, which the main one combustion control which happens in limited operation range between knock and misfiring has limited the use of these engines. Hence approaches like adding synthesis gas, using exhaust gas recirculation, controling effective comperession ratio by using variable valve timing, changing the input conditions...
Factorial Design of Experiments to Identify Effective Factors on Domestic Vehicle Emissions and Fuel Consumption
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor)
Abstract
Reducing air pollutant emissions from vehicles is a difficult and time consuming procedure which needs utilizing of modern emission control equipment and setting strict regulations for car factories and drivers as well. How efficient these policies are and proposing operative solutions for air quality improvement depend on developing a sustainable model which is used in vehicle emission predictions and their share in total emissions. Emission factors are not constant values as they can be affected by various operational and ambient parameters. Development of Emission inventories calls for a huge number of measurements using different vehicles in diverse conditions. Thus, recognition of...
Development and Application of Mobile Source Emission Factor Matrix for Use in Wrf/Camx Air Dispersion Model of Tehran
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor)
Abstract
Tehran, with approximately 750 km2 of land area, a population of more than 8 million people with about 4 million active on-road vehicles, is dealing with serious air pollution problems. To model the environmental phenomenon precisely, this study aims to develop on-road air pollutant emission factor matrices based on existing traffic in Tehran routes and to run air quality modelling within Tehran geographic boundaries. We developed emission factor matrices using SMOKES-MOVES emission modeling system. To do so, we calculated on-road emission factors from actual traffic-related data and run MOVES emission model. And use use them for different pollutants considered in air quality models. Then,...
Studying the Behaviour of Split-Level Structures with Semi-Rigid Connections
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
Past earthquakes show that irregular structures have been more vulnerable than their regular counterparts. One of the common types of irregular buildings in urban areas is split-level ones. On the other hand, beam-to-column connections in steel structures are mostly of "semi-rigid" type. In this work, effects of different levels of rigidity of connections, 100%, 75%, 50% and 25%, on the behavior of a number of two-dimensional split-level steel structures, with 1.5 m difference in levels of floors, 2, 3, 5 and 6 bays, and 5, 10 and 15 stories, were studied. All frames were analyzed “with” and “without” considering the P-∆ phenomenon, with two methods, ‘equivalent static load,’ and ‘modal...
Micro-modeling of Tehran 4-stroke Gasoline Motorcycle Fleet Emission and Investigating the Effects of Increasing Fueling System and Engine Technology Level
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor)
Abstract
The city of Tehran is dealing with air pollution problems for years. Providing a solution for this problem requires information about different pollutants emission sources. In this subjects, emission factors and emission models are essential tools for decision makers. Among different mobile emission sources in Tehran, motorcycles are of high importance. In this project, for the first time in Iran, exhaust gas pollutants emission of 66 motorcycles with different ages and engine displacement volumes were measured according to Euro-3 standard certification procedure. Measurement results showed that none of the tested motorcycles passed the Euro-3 certification limit on CO emission. Calculations...
Partially Homogenous HCCI Combustion Chemical Kinetics Model Initial Conditions Development by CFD Modeling
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor)
Abstract
Homogeneous Charge Compression Ignition (HCCI) engines are the new generation of internal combustion engines which have diesel-like thermal efficiency, while they have low nitrogen oxide and soot emission. One of the major problems of HCCI engines is combustion timing control due to its dependence on reactivity of the charge and chemical kinetics. Moreover, limiting operation range between knock and misfiring is the other drawback of using these kind of engines. In the present work, partially homogeneous HCCI combustion in a single cylinder diesel engine is modeled using Computational Fluid Dynamics (CFD) coupled with chemical kinetics. Simulation includes the engine cycle from exhaust valve...