Dual criterion equivalent linearization approach for yielding structures under earthquake excitation

, Article Structural Design of Tall and Special Buildings ; Volume 21, Issue 3 , 2012 , Pages 155-177 ; 15417794 (ISSN) Rahmatabadi, P ; Khaloo, A ; Sharif University of Technology

2012

Abstract

In order to estimate both maximum displacement and maximum inertia force of bilinear hysteretic system subjected to earthquake motions, an equivalent linearization approach with new effective parameters is presented. Effective mass and effective damping ratio as pair of effective parameters instead of the effective period and effective damping ratio in existing equivalent linear systems are introduced. Two error measures for displacement and inertia force are defined. Error distributions over a two-dimensional parameter space of effective parameters are analysed, and the parameters are determined through a statistical approach with a dual optimization criterion for displacement and inertia...

Determining Response Quantities in Yielding Structures with Viscous Damping

, M.Sc. Thesis Sharif University of Technology Rahmatabadi, Payman (Author) ; Khaloo, Alireza (Supervisor)

Abstract

In recent decades, considerable attention has been paid to application of passive energy dissipation systems in design of new buildings as well as in seismic rehabilitation of existing ones. The increased application of these devices in structures will depend on the availability of simplified methods for their analysis and design. In this study, considering high viscously damped single-degree-of-freedom systems, an equivalent linear system with new effective parameters is introduced which has capability to predict maximum displacement and maximum inertia force of the structure simultaneously. Effective mass and effective damping ratio as pair of effective parameters instead of the effective...

Mechanical properties of concrete containing a high volume of tire-rubber particles

, Article Waste Management ; Volume 28, Issue 12 , 2008 , Pages 2472-2482 ; 0956053X (ISSN) Khaloo, A. R ; Dehestani, M ; Rahmatabadi, P ; Sharif University of Technology

2008

Abstract

Due to the increasingly serious environmental problems presented by waste tires, the feasibility of using elastic and flexible tire-rubber particles as aggregate in concrete is investigated in this study. Tire-rubber particles composed of tire chips, crumb rubber, and a combination of tire chips and crumb rubber, were used to replace mineral aggregates in concrete. These particles were used to replace 12.5%, 25%, 37.5%, and 50% of the total mineral aggregate's volume in concrete. Cylindrical shape concrete specimens 15 cm in diameter and 30 cm in height were fabricated and cured. The fresh rubberized concrete exhibited lower unit weight and acceptable workability compared to plain concrete....

Experimental Studies on Mechanical Properties of Cement Mortar Including Nano Alumina and Nano Silica

, M.Sc. Thesis Sharif University of Technology Jafari Rahmatabadi, Mohammad Hossein (Author) ; Joghataie, Abdollreza (Supervisor)

Abstract

Due to the diameter and size of nanoparticles, they have been applied in various fields to make materials with better properties. In this thesis, the purpose has been to investigate the influence of nano alumina and nano alumina incorporating nano silica particles on mechanical properties of cement mortars. Different portions of nano alumina that include 1, 3, and 5% have been used. Nano silica with 1 and 2% has been used. At first, nano particles were dispersed by sonication with water, and then the cement mortars with various percent of nano additives with the same workability have been made. After different curing periods (7, 28 days), the specimens have been tested for bending and...

Intrusion Detection in Data Networks Using Header Space Analysis

, M.Sc. Thesis Sharif University of Technology Mohammadi, Amir Ahmad (Author) ; Pakravan, Mohammad Reza (Supervisor) ; Kazemian, Payman (Supervisor)

Abstract

Software Defined Networking (SDN) provides a logically centralized view of the state of the network, and as a result opens up new ways to manage and monitor networks. In this dissertation a novel approach to network intrusion detection in SDNs is introduced that takes advantage of these attributes. This approach can detect compromised routers that produce faulty messages, copy or steal traffic or maliciously drop certain types of packets. To identify these attacks and the affected switches, we correlate the forwarding state of network---i.e. installed forwarding rules---with the forwarding status of packets---i.e. the actual route packets take in the network and detect anomaly in routes....