Sharif Digital Repository

With the popular choice of using underground structures and tunnel in big cities and with significant damage in recent large earthquake; therefore more attention is given to the behavior of the underground structure in seismic area. The purpose of this thesis is to present the Soil-Tunnel-Structure Interaction analysis performed for different dynamic load condition. Therefore we modeled a 3D intersection part of two different tunnels in homogeneous soil by ABAQUS software. The soil and concrete structure of tunnel is modeled by three dimensional solid finite elements and the boundary of soil is modeled by three dimensional infinite elements with 8 nodes. The results demonstrate the geostatic... 

Earthquake motions are among random excitation loads. For that we used random vibration approach to estimate response of multi-degree of freedom base isolated structures under ground excitation. Some models including linear model ,nonlinear Bouc-Wen and BBW models are studied for modeling the superstructure .Several base isolation models including the laminated rubber bearing, high damping laminated rubber bearing ,resilient-friction base isolator with or without sliding upper plate and the Electricity de France system, are studied . El Centro 1940 and Mexico City 1985 earthquake which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations... 

Shear walls are commonly used in tall concrete buildings to resist lateral loads. Due to the presence of regular door or window openings, a shear wall is often divided into smaller wall units coupled together by coupling beams. In any case, the earthquake resistance of a coupled shear wall structure is highly dependent on the nonlinear behaviour, especially the strength and ductility, of the coupling beams. Many existing building structures without provisions for resisting earthquake loads might no longer be considered to be up to the new standard due to increased-load specifications in the seismic code. A large number of RC coupling beams might require rehabilitation or retrofitting to... 

In recent years, the application of base isolation as a seismic design strategy for reducing the effects of earthquake ground motion has become an advantageous method and much effort has been devoted to base isolation research and there has been a growing acceptance of this approach. In this research, the effect of using base isolators in reducing the dynamic forces of piers and abutments of bridges is studied. More specifically double-span bridges are the target of this research. After modeling a regular bridge in a typical analysis program, it is excited by different earthquake accelerograms and then the effect of using base isolators in dissipating the earthquake energy is investigated  

Natural phenomena, such as earthquakes, floods, and hurricanes, have been, and will be, one major source of mankind disastrous problems. Mankindinterventions to relieve this heavy pressure on humanity have been divided into four categories: mitigation, preparedness, response, and recovery. This study is in the response phase, and aims to find an optimal network to help people in the devastated part of a city, hit by a major earthquake. Such earthquakes demolish buildings over the people inside, causing them fatal harm and serious injuries. At the same time, they ruin the city infrastructures (life lines), including transportation networks, preventing flow of relief supply to reach to the... 

Long-term effects of natural disasters, like earthquakes, in many cases have been reported high on transportation networks. Disruption in this lifeline network's performance imposes high social and economic costs upon the society. Undoubtedly, retrofitting the structures of all network links (or constructing new links) are practically impossible and economically infeasible. One solution to this problem is finding a method for determining the network's important links, and retrofitting their structures. Based on this concept, an optimization problem of network performance improvement under these stochastic events is introduced. In this problem, a link importance index for network links is... 

Natural disasters have been with the earth, and felt critical as far back as human history. These incidents are inevitable, but their effects may be controlled. One important problem after a disastrous earthquake is the management of people’s vehicular movements in a chaotic situation. This study is an endeavor to envisage what would possibly happen after such an incident, and how could we possibly control or manage the traffic in such an occasion. We start with the analysis of the online reports of similar past incidents, and try to picture how people react to these events. We try to identify the trip purposes that have been shown to be pursued, and the respective origins and destinations.... 

In this study, a new type of metallic yielding damper called Telescopic damper is proposed and analyzed numerically. The damper comprises of three concentric steel tubes connected together by lead shear keys. The relative axial deformation of steel tubes under axial forces results in shear deformation and yielding in lead shear keys and dissipates energy. The inner steel tube has a lock which limits its movement to some certain extent and beyond this limit the outer tube activates. Therefore, a multi-linear force-deformation behavior with two different yield plateaus is expected for the introduced telescopic damper. The multi-level yield plateaus of damper makes it effective in both low and... 

The parametric study of a new introduced metallic yielding damper called telescopic damper is addressed. The telescopic damper comprises of three concentric steel pipes connected together by lead shear keys. The inner and outer steel pipes are subjected to axial loading which results in the shear yielding of the embedded lead cylinders. The inner steel pipe has a lock which limits its movement to some certain extent and beyond this limit the outer tube activates. Employing ABAQUS software, the behavior of damper under cyclic loading is studied numerically. The finite element model is verified by available results in the literature. The effects of inner and outer steel pipes thickness,... 

The aim of this study is to evaluate post-earthquake travel behavior in Tehran. After a horrible disaster, like earthquake, people’s travel behavior may change substantially in comparison with normal condition. If people’s travel behavior can be predicted after an earthquake, then authorities can manage travels for emergency medical services in a more efficient way, so the casualties are profoundly diminished. To collect a formation, a questionnaire about socio-economic characteristics of people and their post-earthquake travel behavior was designed. According to the obtained results, time of occurrence and severity of the earthquake are of the utmost importance. So if the earthquake occurs... 

Occurrence of natural disasters such as flood, windstorms, tsunamis and earthquakes has caused striking effects on critical infrastructures like power systems in recent decades. There are some examples of high-impact low-possibility (HILP) events which causes catastrophic effects on power systems. Traditionally, planning and operational studies of power system have been run taking into account some reliability metrics. Although, the reliability indices can represent the ability of a system in confronting with possible failures of components, they are unable to efficiently consider the effects of severe events such as earthquake and other HILP events. Moreover, traditional power systems were... 

Earthquakes are of self-organized critical phenomena, the phenomena that exhibit scaling behavior without tuning external parameters. A number of models have been proposed to describe such features of earthquakes, the most known one is the Burridge-Knopoff model. The Burridge-Knopof model is a spring-block system where the blocks slip on a plate which has friction and are attached through some other springs to a moving plate. Because of the moving plate the blocks become under increasing tension but do not move until the tension overcomes the static friction. As a result, the blocks will move and then stop repeatedly. These movements are avalanche-like and their intensity obeys a power-law... 

Liquefaction is an important phenomenon in geotechnical engineering which can cause severe damages to structures. Liquefaction-induced lateral spreading is defined as the lateral displacement in mild slopes or level grounds ending in free faces (such as quay walls) triggered by liquefaction in subsurface soil layers. During recent years, extensive studies have been conducted around the world documenting liquefaction induced lateral spreading and its effects on deep foundations. In the present study, a series of shaking table experiments which were previously conducted at Sharif University of Technology are numerically simulated using the three dimensional finite difference based program,... 

This dissertation proposes a new platform and a new software for evaluation of urban Water Distribution Network (WDN) resilience. Resilience is considerd as the ability of an infrastructure to come back to steady state after being affected by any environmental or man-made disturbance. WDN, as an essential infrastructure, has major role on resilience and sustainability of cities and communities. Today, uninterrupted performance of WDN is a basic need of people who live in cities. This uninterrupted performance becomes bolder in face of man-made or natural disasters like earthquake. The uninterrupted performance of a system is dependent on the system’s resilience. Majority of researchers... 

In this research, a single degree of freedom (SDOF) system equipped with a telescopic damper is analyzed under earthquake excitations. In order to assess the effectiveness of telescopic damper, some SDOF systems equipped with other types of dampers including viscous damper, friction damper, T-ADAS damper, and Curadelli’s lead damper(CLD) are also analyzed under similar excitations. Inspired by CLD damper, this TLSD damper is primarily introduced, developed and tested at Sharif University of Technology in Tehran by Mr. Pournamazian in 2016. Results shows that the telescopic lead shear damper can increase the CLD damper displacement by 100%. To get better results in terms of damper’s behavior... 

The main goal of partake quake-attenuating in buildings is to absorb energy and to attenuate the exerted forces into structures as a result of ground motions. Notwithstanding achievements and developments in the field of dampers production, applying of dampers in structures is proportional to following complicated technology and subtle engineering. Installation and initiation of dampers depend on educated and expert crew; moreover, such attenuating systems need maintenance and repair during the useful structural life time. Therefore, nowadays civil engineering suffers from the lack of such quake-attenuating systems to be able to respond simply but applicable mechanism at the same time for... 

The aim of this research is presentation of A framework to select the appropriate combination of retrofit and insurance in order to reduce earthquake losses. The vulnerability of buildings to earthquakes can lead to significant damage to owners and residents of these buildings. It is imperative that appropriate measures be taken to reduce these adverse effects before the risk occurs. Some of these measures, such as seismic retrofit of buildings, can reduce the vulnerability of buildings and, consequently, financial and human losses. Some other measures like insurance, in the event of an earthquake, can reduce the financial losses incurred by owners and residents of vulnerable buildings.... 

Annually Natural disasters make tremendous impacts on societies. Fatality rate of earthquake in Iran is almost more than all other disasters. There are numerous problems in disaster Management's of Iran and other countries. One of the disaster Management's phases is response phase which mostly depends on emergency processes, so most of papers working on this phase, plan for emergency state by using different techniques.All the studies seeking the response phase, try to reduce the loss of disaster by the use of immediate response to earthquake, pointing the disaster after occurrence. But Another point of view is to make loss reduction by precautious activities and plans. Actually, the loss... 

Electrical power is an inseparable part of human life. Therefore, design and analysis of electrical transmission towers have always been important for scientists. In common design methods due to the lightness of these structures only the wind load is considered and earthquake effects are neglected. On the other hand, regarding regulation No.2800 a lot of areas of Iran are located in earthquake zones. Therefore, it is necessary to evaluate the performance of these structures against earthquakes. In this research, regarding conducted studies, we decided to use incremental dynamic analysis method (IDA) in order to evaluate seismic performance of the tower. In sake of thoroughness of the... 

Resiliency is, now, recognized as a vital characteristics of every urban transportation network. This is so, because transportation network is considered as a life-line in disastrous events, such as major earthquakes. In this respect, design of networks may be considered (1) before the incident, (2) after the incident for 72 hours, and (3) from this 72 hours on. From the point of view of (1), design of the network may be considered as strengthening important links under budget constraints to withstand the design incident, in order to be able to function properly (to help the affected people, to evacuate the populated area, etc.).Design of network based on the point of view of (2), the one...