Sharif Digital Repository

Elevated concrete tanks have a wide range of applications in storing drinking water, firefighting, sewage, oil, toxic chemicals, and similar fluids. Therefore, due to their usage, these tanks are usually placed in the category of very important structures and vital arteries. Consequently, their design against seismic loads and their proper performance during earthquakes are of great importance. The endeavor time Analysis is a seismic analysis method in which the structure is subjected to an increasing dynamic excitation whose intensity gradually increases over time. The structure's response over time is examined, and based on the corresponding response to various levels of excitation... 

In most places in the world as it is in our country, structural vibration caused by earthquakes are among the most destructive menaces for the building. For this reason one of the main goals for civil engineers is constructing structures that can perform properly in an earthquake-exposed situation. For moving toward this goal it is necessary to estimate structural responses considering probable earthquake excitation and use these data for design of new structures or retrofitting of existing ones. In this research, the capability of a new method named Endurance Time analysis in seismic assessment of concrete moment frame is investigated in nonlinear range. ET is a new dynamic time history... 

Preventing critical damages to structures and hence saving the lives and money is an inevitable work which a designer has to do. During the earthquake, huge amount of energy applies to the structure and finding a way to reduce transfer of this energy to main structure is crucial. For this purpose, Structural Control systems may be used. Metallic Dampers are one of those systems which absorb the earthquake input energy by having nonlinear deformations. In this Thesis, one type of this dampers which is innovated by Estekanchi, have been studied .Indeed, this damper is a connection between bracing and main frame. In this damper a U shape part acts as a sacrificing portion and absorbs energy by... 

The purpose of this study is to evaluate the performance and seismic costs for pre-designed bridges according to the Iranian Bridge Code, which maps and details are available in Code 294. In order to evaluate performance, seismic costs of a structures are determined over its life cycle and these costs are compared eventually. Seismic costs are divided into two parts of the initial cost and life cycle cost of the structure. The initial costs depend on the cost of constructing the bridge, but life cycle costs are depends on seismic damage for structure and its users over the useful life of the bridge. These damages include the cost of maintenance of the bridge over its useful life and the... 

This thesis investigates the dynamic response of a viscoelastic plate resting on a viscoelastic Winkler foundation subjected to the excitation of a moving mass. Through application of the Laplace transform, the governing equation of the problem is derived for a general viscoelastic material. Thereafter, an analytical-numerical method is proposed in order to determine the dynamic response of the viscoelastic plate. The method is based on transforming the governing partial differential equation into a new solvable system of linear ordinary differential equations. To that extent, the proposed solution proves to be applicable to plates made of any viscoelastic material and with various boundary... 

One of the main challenges in the design of wireless sensor networks (WSNs) is minimizing the energy consumption while simultaneously maximizing the performance of sensors. In this thesis, we have considered WSNs based on beacon enabled IEEE 802.15.4/Zigbee Standards with low rate applications like temperature, humidity and light sensing, which mainly have been used in a smart home environment, and proposed a cross-layer design to overcome this challenge. The design involves an optimizer module that captures the application layer and MAC sub layer behaviors. Based on these behaviors, the optimizer dynamically changes the rate of node’s traffic at the application layer and the priority of... 

We present a home energy management system that is able to manage home energy demand and resources to achieve minimum household payment in electricity dynamic pricing.Communication is used to collect needed data from the home energy system members and users in order toimprove demand and resources management. Some of the needed data comes from appliances and solar panels by wireless sensor network and some other is received from home users by a user interface.
Two algorithms are proposed that the first algorithm goal is to minimizing household payment and the second algorithm goals are flexible implementiation and decreasing household payment. To decrease household payment, these... 

In this thesis, the effect of cognition in wireless networks is studied. In a wireless communica-tion network, cognition is the ability of a device to sense the transmissions of neighboring nodes and adapt its own transmission to the sensed environment. Cognitive radios are very attractive be-cause of the increasing need for more efficient use of frequency spectrum. The goal of this thesis is the analysis of cognitive radio networks from an information theoretic perspective and to this end statistical models of the wireless medium with a limited and tractable number of devices are uti-lized. We consider three different models in three parts of the thesis. First, we consider a new... 

The use of Radio Frequency Identification is increasing rapidly. The reason is the capability to transfer data wirelessly without line-of-sight necessity, high data rate and long read range. The main advantage of barcode is its lower cost which has ensured its existence for many years. The applications and materials that are identified by RFID increase as the price of RFID tags decrease. This Project deals with the front-end of an Integrated RFID Reader for the UHF band. The bottleneck of the design is the presence of a large interferer just hundreds of kilohertz apart from the desired signal which is at about 900 MHz. The key idea of the design is utilizing feedback in order to cancel... 

Today, smart devices have become an integral part of everyday life. The Android operating system is also the most popular operating system of these devices, and as a result, various malwares are produced and distributed for this operating system every day. This makes it especially important to investigate these malwares. This includes finding people involved in the development and distribution of malware, as well as discovering other malwares created by them. Discovering other involved entities, such as social media accounts, websites, Android store accounts, and taking steps to prevent malware from being distributed by them is another aspect of this story. In order to deal with organized... 

The structure performances during past earthquakes indicate the importance of predicting behaviors of irregular structures under earthquakes. If the irregularity exceeds an expected limit, a seismic analysis should be carried out by a dynamic analysis method. The Endurance Time (ET) is a time-history method, base on dynamic analysis for seismic analyzing and designing the structures, in which structures are subjected to intensifying accelerogram functions and their Endurance Time is measured. One of the most applicable methods for RCF analysis is the Concentrated Hinge Model which is used in this research too. The needed parameters for modeling plasticity in concentrated hinge are achieved... 

In recent years, by development of computer and analytical software, engineers intended to do complicated and delicate dynamic analysis instead of static ones. This cause reduction in uncertainty in structures analysis and designing, that improves environmental, economical, and safety performance. Currently there are two common methods which are accepted in major building codes, they are spectral and time history dynamic analysis which the former analyzes structures by using design code spectra based on determination of structures’ dynamic haracteristics, and the latest do it by imposing ground motions on the structure. The spectral dynamic analysis method has some errors and causes... 

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... 

Endurance Time (ET) is a fairly comprehensive analytical method based on time history analysis applied for evaluating structural systems excited by dynamic loading of earthquake. In such evaluation assessment measure is based on endurance time of structure versus applied accelerogram function and parameters such as stiffness, lateral resistance, period of vibration and dynamic characteristics are not used directly. In this research nonlinear dynamic analysis of elevated steel tanks with laterally braced framed tower under the loading of earthquake records and ET accelerograms was studied and effectivity of ET method in analyzing such elevated tanks was verified. Due to complication of... 

In this research the appilication of a new method named Endurance Time (ET) analysis in seismic analysis of multi span bridges in linear and nonlinear ranges is investigated. Endurance Time is a time history based method of seismic analysis. In this method structure is subjected to an intensifying predefined acceleration function and different damage indices of the structure are evaluated through analysis time. The Endurance Time criterion and the Endurance Time acceleration functions have been generated in previous researchs of ET group. Using 7 earthquake records which are selected from hundred ones of PEER database based on FEMA p695 recommendations, several scaling methods are used to... 

In the earthquake conditions, the collapse of cooling towers can stop power station activities and heavy financial losses that can be led increasing disaster dimentions finally. In this thesis for analysis of concrete hyperbolic cooling towers and generally for analysis of shell structures, the endurance time (ET) method benefits are used. Also with comparision between ET and standard time history method (THA), accuracy and probable errors of ET method are discussed. It should be noted that ET method is a new time history based method of seismic analysis expect that in this method, structure is imposed under specific intensifying acceleration functions. ET method is capabable for nonlinear... 

The Endurance Time Method is reprehensively new and comprehensive method for analyzing and designing the structure quality in based on performance that is related on time history analysis for investigating structure systems under dynamical instigation in result of earthquake. In this evaluation the index comparison in based on endurance time against of applied acceleration function. The result of the structure will plot against time, until the structure will achieve to a special amount of damage. The high endurance time means high performance. While the damage index will maintain less than allowable limit until endurance time, the structure will be approvable.In this project the ability of... 

Recent studies show that irregular structures have been damaged more than regular ones during earthquakes. This proves importance of seismic response determination of this type of structures. Today, Codes define irregularity in structures and restrict seismic analysis and design of these types of structures. The Endurance Time (ET) method is a time-history based dynamic pushover procedure for seismic analysis and design of structures that has been recently proposed in Sharif University. This thesis illustrates ET capability in analysis and design of vertically irregular frames. Irregular frames with three, seven and twelve story high were designed with two types of mass and stiffness... 

Nowadays using traditional hollow clay brick in buildings to make walls and partitionsisvery common. Non-load-bearing walls in buildings are used as architectural elements for design purposes and protecting the people that are inside the building from cold , heat and sound pollution .Due to the new technologies and developing building codes interms of structure , non-load-bearing walls behaviour that is always neglected seems necessary to be considered. In this research we have investigated the static and dynamic behaviour of a patented non-load-bearing wall made up of a claybrick system with specially-designed-precision grooved faces that eliminates conventional cement mortar and results...