Sharif Digital Repository

The main purpose of this study is computational modeling of saturated deformable porous media using multiscale finite element method and explicit modeling of discontinuities such as microcracks at the microscopic scale. The real engineering problems we deal with in the simulation of the phenomenas happening in nature or industrial applications, in contrast to the simplifications being assumed, occur in heterogeneous materials. Although most microscopic heterogeneities are not present in macroscopic scale, they do have their effects on material behavior. In the computational homogenization method, the problem is analyzed coupled in two scales, therefore, the macroscopic behavior of media is... 

Nowadays, with the advent of Autonomous Vehicles(AV), Researchers in different areas focused more on this type of vehicle. Research shows that autonomous vehicles are faster and more precise than Human-driven vehicles(HDV). So if all the users in a road use autonomous Vehicles, the road’s capacity increases; this Thesis develops a mathematical approach for designing AV exclusive lanes for a time horizon in which there are two types of AVs and HDVs on the road. Considering each type of vehicle’s relative performance for an OD pair in the given year, the demand for that OD pair for the next year calculates with a diffusion model. Designing AV exclusive lanes problem is formulated in a bi-level... 

This paper proposes a novel probabilistic approach to account for soil-structure interaction (SSI) in the seismic design of building structures. In this approach, an SSI response modification factor, RSSI, is introduced to capture SSI effects on the seismic performance of structures. The proposed procedure quantifies RSSI such that the probability distribution of the collapse capacity of the structure designed to account for SSI concurs with that of the structure designed using the default fixed-base provisions. The proposed approach is employed for special steel moment frame buildings with surface foundation. A surrogate single degree of freedom (SDOF) system is developed in this study and... 

In this thesis the hourly concentration of different gaseous air pollutants in Tehran is modeled using Land Use Regression (LUR) and Artificial Neural Network, separately. Both models are provided with the same set of input data; the first step is to find these data. Since traffic affects air pollution, information about traffic conditions is one of the main inputs in air pollution modeling. Therefore, to obtain traffic information, in this thesis, first a novel method is developed to extract and analyze Google Maps traffic data. In this method, image processing is used along with the Geographic Information System (GIS) to count the number of pixels of different traffic colors for each road... 

Master curves describe the behavior of asphalt binders over a wide range of temperatures and loading frequencies which are utilized by various predictive models in design and analysis procedure of asphalt mixtures. Frequency sweep test is extensively used for construction of master curves within the temperature range of 4 ̊C to 82◦̊C and frequency range of 0.01 to 30 Hz. There is a concern that master curves are unable to accurately represent the low temperature (below 4 C) behavior of binders. In this study a new cyclic loading pattern for the bending beam rheometer (BBR) test was utilized to conduct the low temperature tests and generate an isotherm compliance curve for incorporating the... 

In this study, using the correspondence principle and Laplace transform, the results obtained in the elastic medium for the Eshelby inclusion problem are expanded into the linear viscoelastic medium. The simplicity and breadth of application of the correspondence principle is so great that it enables one to obtain closed-form solutions in Laplace domain for problems that have closed form solutions in elastic media. However, in complex problems, the long formulas lead the user to apply numerical methods to perform inverse Laplace transform. First, by taking advantage of Green’s function the strain and stress fields are obtained in Laplace domain for the points lying inside and outside of an... 

Asphalt binders are known to exhibit an inherent ability to repair damage. Such selfhealing potentially affects the fatigue damage performance of bituminous materials. There is no consensus about the effect of aging and polymer modification on cohesive healing. Also, the effectiveness of rejuvenating agents have not been addressed in previous studies. In the current study, three healing indices are presented to precisely quantify the healing capacity of various binders. These indices have been defined using the damage characteristic curves derived from interrupted linear amplitude sweep (LAS) tests. Instantaneous healing (IH) describes immediate reduction in accumulated damage after the rest... 

Studying the performance of irregular structures in past earthquakes reveals that due to their severe vulnerability, we need to accurately assess the behavioral characteristics of such structures. On the other hand, all existing seismic codes recommend the use of response modification factor to determine the base shear, design forces of the members, and the design drift ratios, which seem to have limited comprehensiveness. Moreover, the response modification factor for a structural system is discussed in a general manner and the effect of factors such as number of bays, number of stories, span length, story height and irregularities are not considered. In this research, the effects of... 

In this study, community resilience after a disaster is optimally enhanced for interdependent infrastructures through prioritization of recovery operations considering limited resources. Optimal enhancement of community resilience can be performed at two levels: Pre-disaster and Post-disaster. In the pre-disaster level, resilience enhancement is achieved through optimization of long-term decision making that includes optimized allocation of resources to retrofit of buildings. However, in the post-disaster response and recovery period, allocating resources to retrofit or backup systems is infeasible. Therefore, in the post-disaster level considered in this study, resilience enhancement is... 

Vehicle Kilometers of Travel (VKT) as one of the most important indicators of travel behavior, express the total kilometers traveled by all vehicles on city networks. Due to the expansion of urbanization and, consequently, the growth of cities, the need for awareness of citizen’s travel behavior and planning for it, is felt in more cities. Spatial transfer of a model which refers to transfer a model from on region (context) to another one, helps different regions to benefit from the results of modeling with a relatively low expense.The main purpose of the research was evaluating spatial transferability of models developed to estimate VKT in three metropolitan cities of Iran which are... 

The goal of this research is to solve the traffic assignment of electric vehicles with considering trip chains. Limited driving range of electric vehicles is considered as one the most important obstacles for the development of these cars. The worry that the battery will run out of power before the destination is an important issue regarding the electric cars and people usually experience it more in trip chains. In this research, a complementary model and a linearization method is used for traffic assignment. In determining shortest paths in the traffic assignment, in addition to considering the travel time and the distance limit, the constraint of passing through activity nodes is... 

Observation made after previous earthquakes revealed that irregular structures had shown unfavourable performance compared to their regular counterparts. In general, structural irregularities are classified into two categories, “irregularity in plan,” and “irregularity in elevation (height).” In order to investigate the effects of irregularities on the “response modification factor,” three types of 3-D steel structures were studied, namely type 1: regular ones, type 2: split-level ones (having irregularity in elevation), and type 3: irregular in plan as a result of having eccentricities of 5%, 10%, and 20% between the centers of mass and rigidity. All the studied frames were initially loaded... 

In this thesis, an analytical solution is presented for pure bending of SMA curved beams with rectangular cross section and both loading and unloading stages are considered. Moreover, by appropriate simplification, its application in elastoplastic pure bending of curved beams made of regular materials is investigated. Elastic-linear kinematic hardening behavior of the material is assumed and both loading and unloading stages are considered. Exact plane plasticity solution of the elastoplastic pure bending of curved beams made of regular materials which exists in loading and is available for rectangular cross section has many unknowns and longsome equations. Therefore, it is difficult to use... 

The relationship between travel behavior and Built Environment has been context of variety of research during past decades. Many modern urban development theories such as new-urbanism and smart growth are commonly based on interactions between these two concepts. This research is aiming to analyze the effects of built environment on household trip generation, mode and destination choice as specific indices of travel behavior, based on travel diary data of Shiraz city. Multiple Linear Regression and Multinomial Logit Model concepts are used to analyze aforementioned travel behaviors in two levels. Base models predict socio-economic variables importance and expanded models are used to test... 

A probabilistic approach to modeling the seismic damage incurred by structural and nonstructural components is developed in this study. For this purpose, Bayesian linear regression is employed to characterize the epistemic uncertainty in the model. In this approach, regressors are constructed based on the mechanics of damage. In turn, the probability distributions of the model parameters and the model error are quantified by Bayesian regression using real-life data from laboratory experiments and/or post-earthquake inspections of damaged components. The study presents the stepwise procedure of collecting the observations, quantifying the repair costs, developing model forms, performing model... 

The necessity of providing synthetic acceleration records suitable for seismic assessment of the structures in the regions whose seismological history has not enough instrumental recordings has become one of the main concerns of the earthquake engineers. Despite being accurate in estimating earthquake ground motion, physics-based methods involve complicated procedures and need the detailed information about source, path and the site conditions of the scenario event which is not available for lots of engineering problems. The main goal of this dissertation is to introduce a novel stochastic method for the simulation of the non-stationary earthquake acceleration records compatible enough with... 

One of the most important criteria in travel analysis is the vehicle kilometer traveled (VKT). The distance which personal cars, vans or other automobiles travel is measured through this criterion. In addition, the VKT is used in transportation planning, accident analysis, transportation budgets assignment, and estimation of automobile pollutions. In this work we process origin-destination data gathered in Shiraz, Iran to estimate the VKT. To this end, we incorporate the linear regression and geographically weighted regression (GWR) methods. Through this research, data from origin-destination statistics of Shiraz, gathered by the transportation institute of Sharif University of Technology in... 

The dams as one of the most costly and most fundamental infrastructure that human steps to make their, always paid special attention to people in different historical periods. According to the high cost of this structure, optimum design is so important. On other hand stability of structure as main aspects of the design that in the absence of it is threatening the lives of many people in downstream. Therefor the engineers consider two important aspect when they want to design a dam. The first step in designing is determinate the external loads. A designer not only must recognize this loads but also by using the material that he consume in the body of dams reach to a safety structure in During... 

Marine risers are tubular components, which are used to transfer fluids between seabed and floating platform. They may have a great share in cost of oil and gas production systems. One of the risers used in deep-water, is Steel Catenary Riser which is an economic alternative. However, amongst issues in designing this type of risers, high stress level in floating platform connection point and seabed touch- down zone is notable which is created due to platform movements, currents and wave loading and finally, leads to fatigue life reduction. Using buoyancy modules which are attached to risers is one of stress levels reduction solutions in hotspot points. In this study, considering the Caspian... 

The main objective of this study is to identify the contribution of different damping mechanisms in equivalent damping of inelastic soil- structure systems which can be used to reach a better estimation of inelastic soil- structure systems response using some simplified methods. This mechanisms include the material damping of soil and structure, radiation damping of soil and also the structure’s nonlinear behavior. Despite the studies have been done, even in the fixed base systems, there is not an exact prediction for the contribution rate of inherent damping and energy absorption related to nonlinear behavior in equivalent damping of system. Considering the flexibility of soil under the...