Sharif Digital Repository

Rail transport system plays an important role in the development of the economies of the countries. This system is worn out over time by operating and weather conditions and requires maintenance and repair. One of the objectives of maintenance operations is to maintain tracks in an acceptable level and prevent their excessive deviation from the optimal situation. This deviation is called geometric irregular deviation. If these irregularities go away, they can cause traffic accidents and derailment in addition to losing travel convenience. So avoiding the deviation of the tracks is a very important. Maintenance management systems in the past few decades have been considered by the experts in... 

Today, building sectors account for 34% of total energy consumption in Iran. Increasing demand of the comfort level along with population growth necessitates much more attention about energy requirements in the country. Such phenomenon has already raised concerns about the heavy environmental impacts. The present research studies minimization of global warming potential effect for an educational building by developing life cycle optimization model. The Department of Engineering of Sharif University of Technology is selected as the case study and optimal solutions has been achieved for this building. Results state that implementing cogeneration and renewable energies can reduce20 -25% of the... 

This dissertation proposes a probabilistic framework for optimal calibration of design provisions based on the minimization of lifecycle cost (LCC) and its uncertainty. Subsequently, this framework is utilized to determine the optimal robust design base shear coefficient of building structures, and propose a methodology for codifying it while preserving the current structure of the base shear equation. In the first part of the proposed methodology, various structures are designed with different seismic base shears. Then, at each site, their LCC comprising the construction costs and seismic losses is calculated. Various types of seismic loss considered in this study include the direct... 

costs of construction of a structure include: initial construction cost, maintanance cost, seismic risk cost and etc., that in this investigation,the seismic risk of multi-span conc. & steel bridges has been compared. the seismic damage is converted to equivalent finincial value by the concept of life-cycle cost, and then is compared with initial construction cost of structure.in this method, assessment of seismic damage based on structure response, in different earthquake intensity and by damage state concept is done. ET method has been used for predicting response of models.in this investigation two conc. & steel models, with similar geometrical specification and different design results,... 

The actual value of structures should not be evaluated only based on initial cost, because failure cost and economical losses due to corrosion and natural hazards can be catastrophic. The aim of this research is Comparative study of life cycle cost of steel and concrete building systems designed based on standard 2800 by Endurance Time Method. These costs include initial cost and life cycle cost Due to the aftermath of the earthquake in the life of the structure. In this research, because it requires a lot nonlinear dynamic time history analysis, Endurance Time Method used which is both good accuracy and also drastically reduces the cost of computing-off. Selected models for the study, four,... 

process design and decision-making about it are challenging activities that involve optimizing conflicting goals such as cost, technical feasibility, and environmental impacts. These conflicting goals can be analyzed by considering the complete life cycle of a process or product in the initial design and decision-making. Life cycle analysis follows the environmental effects throughout the life cycle of a product, including extraction, transportation, production, consumption, and disposal. Life cycle assessment includes four fundamental stages: goal and scope definition, inventory analysis, life cycle impact assessment, and interpretation of results. The aim of this project is to investigate... 

Damming projects always have been important while construction, operation and even demolition due to their major effects on society, environment and economy. Although researchers have focused on one or a few phases of construction projects to develop sustainable infrastructures, the research community has to consider long term effects of developments too. There are a variety of such effects that ignoring them will cause construction of not convenient infrastructures i.e. air pollution and over-consumption of energy resources while construction, operation and demolition. Therefore, it is suggested to consider life cycle assessments to include all bad effects in all phases of a project. Dams... 

Every year, a lot of costs are incurred to dairy production sets for new product production or product improvement.cosidering to the high amount spent on this sector so if there is not any cost management and cost planning based on life cycle of projects , costs will increase .As a result today considering of life cycle in cost management is a Essential principle . In this study we consider kalleh dairy company as a case study and resuls of this study will be a complete economic model for cost management based on the life cycle of dairy projects  

Infrastructure systems play a critical role in the economic and social activities of a community. Effective and continuous performance of these infrastructure systems is essential to the welfare and prosperity of the communities. Infrastructure systems comprise networks of interdependent assets that are built through a long and costly process. These assets are subject to a variety of factors that reduce the performance and reliability over time. These factors also increase the vulnerability of infrastructure assets in face of future probable hazards. In order to ensure the continuous and uninterrupted performance of infrastructure assets in post-hazard situations, asset managers should plan... 

Schools are known as the educational infrastructure of countries. Most people in the community spend more than 12 years of their education in schools. The organization for development, renovation, and equipping of in Iran, as the custodian of school construction in the country, has moved towards using new technologies due to the problems encountered in schools' construction. Among these tools, BIM is selected to help project management and control. For BIM implementation on the macro scale, readiness assessment plays a significant role. In this dissertation, an attempt has been made to provide a model for evaluating the needs, use BIM, and evaluate the organization by having a strategic... 

Most of the seismic regulations in the Iranian design codes are adopted from the U.S. codes, while the severe earthquake rates with regards to the gross area and total population of Iran is 8.4 and 5.5 times the rates for U.S. respectively. In fact, Iranian rates are between the ones for U.S. and Japan which have up to 200% difference in prescribed strength level in their seismic codes. Poor construction quality regarding defected control in Iran adds to the problem. Therefore, the prescribed strength level of U.S. building codes and thus their target reliability index seems insufficient for use in Iran. Also, previous research has shown that the load and resistance factors in Iranian... 

This study proposes an efficient risk-targeted framework for integrated optimal seismic design and quantifying target safety of steel Special Moment-Resisting Frames (steel SMRFs) with and without various passive damping devices such as Buckling-Restrained Braces (BRBs), Friction Dampers (FDs), and Fluid Viscous Dampers (FVDs). This framework provides an automated design procedure formulated as a constrained single-objective optimization problem to achieve the minimum Life Cycle Cost (LCC) within the Particle Swarm Optimization (PSO) algorithm and can be the basis of current seismic codes for target safety calibration. LCC includes initial construction cost and lifetime seismic losses such... 

Bridge is one of the most important structure that are used in urban transportation system. In recent decade, international standards and codes have introduced “Performance Based Design” for structure design criteria. Large and complex dynamic and time history analyzes are obstacles against this method; especially in finding optimum design that requires repeated analyzes. In this research, application of Endurance Time (ET) method in seismic design of urban concrete bridges has been evaluated and value based design of them has been presented. In ET method, seismic performance of structures under artificial intensifying accelerograms is investigated. Performance of structure in... 

The aim of this research is value based optimum design of structures to minimize the costs imposing on them during lifetime. For this purpose, an optimization procedure is used to get optimum solutions. Therefore, in this optimization problem, total costs are objective functions and required limits of codes are as the constraints. The costs include initial costs of constructing and life cycle costs. The weight of structural components and seismic consequences during the lifetime of structure are used as a criterion to assess initial costs and life cycle costs, respectively. In this research, seismic losses are determined based on the probabilistic seismic assessment framework, which depends... 

The objective of this research is to evaluate the concept of a new design methodology based on the total value of the structure namely Value Based Design of structures (VBD) by the use of potential benefits of the ET method. While prescriptive and also performance based approaches of seismic design commonly try to find a structure with lower initial cost satisfying a number of requirements under seismic actions, a new design approach to incorporate directly the concept of value in design procedure have been formulated here to achieve an economical design with lower total cost in its life time. In this method the design sections of structural elements are considered as optimization parameters... 

The growing amounts of generation of electronic wastes (e-waste) and their increasing environmental impacts require a special optimal waste management strategy. Many different methods have been developed to managing e-waste. To make the best choices according to the conditions of each system, having an adequate knowledge of all methods and comparing them is the most important point. This research aims to design a system for managing e-waste by selecting mobile phones as an example of electronic waste and find the optimal condition of the system to increase economic benefits and reduce environmental impact. Recycling and landfill are selected as the main methods in this project. Four lines... 

Seismic base isolation is the most effective method of protecting and strengthening structures against seismic damage caused by large to small earthquakes and aftershocks. Providing damping and energy absorption of the seismic isolation at the structure's base level can significantly reduce the cost of repairing and strengthening the structure in addition to reducing seismic damage. However, besides these advantages, due to their high cost, seismic isolations in major infrastructure projects, hospitals, and crisis management centers should have economic and social justification. In this regard, a value-based seismic design approach can justify this important issue. In recent years of... 

The objective of this study is to design a real structure based on value using the endurance time method, which is designed according to common design codes. In the value-based design of this structure, a variation of the lateral load coefficient has been used for the design of the investigated structural specimens. The term "value" in this research refers to the total costs incurred over the lifespan of the structure. The initial construction costs of the structure and the life cycle costs are optimized in the value-based design process. The initial construction cost in this research consists of two parts: the first part is variable costs that arise from the consumed materials in the... 

In recent years, due to the economical concerns in the structural design, many researches are devoted to introduce new frameworks for optimization of the construction cost as well as maintenance and rehabilitation costs in the life time. The bridges are the most crucial components of the transportation networks and their appropriate performances assures the flow in the transportation network. Hence, the reliability and response of such infrastructures especially in the emergency conditions and the state of servicibality after the hazards like earthquake play a key role in the social life. So far the design procedure of such infrastructures are only limited to the serviceability conditions as... 

A set of infected computers which are coordinated in some manner by one’s willingness and can perform malicious activities and provide threats in the cyberspace forms a network of bots, namely botnet. Botnet threats are more important and significant than other malwares due to their huge scale. A lot of computers coming together in a network obeying one’s commands allows their controller to conduct, for example, DoS attacks larger than ever seen incidents. This thesis, introduces botnets, their various threats, and an effective technique for detecting them. For this reason, different probable states of bots will be studied and modeled as a coherent bot life-cycle. The bot life-cycle allows...