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1	Behavior and Analysis of a Horizontally Curved and Skewed I-girder Bridge Ozgur, Cagri 09 April 2007 (has links) This thesis investigates the strength behavior of a representative highly skewed and horizontally curved bridge as well as analysis and design procedures for these types of structures. The bridge responses at and above a number of limits in the AASHTO (2007) Specifications are considered. The study includes the evaluation of various attributes of the elastic analysis of the subject bridge. These attributes include: (1) the accuracy of 3-D grid versus 3-D FEA models, (2) first-order versus second-order effects during the construction, (3) the ability to predict layover at bearing lines using simplified equations and (4) the benefit of combining the maximum and concurrent major-axis and flange lateral bending values due to live load compared to combining the maximums due to different live loads when checking the section resistances. The study also addresses the ability of different AASHTO 2007 resistance equations to capture the ultimate strength behavior. This is accomplished by comparing the results from full nonlinear 3-D FEA studies to the elastic design and analysis results. Specifically the use of the 2007 AASHTO moment based one-third rule equations is evaluated for composite sections in positive bending. Layover Steel bridges Skewed bridges Curved bridges One-third rule Second order effects Strength behavior Staggered cross-frames Grid analysis Behavior of bridges FEA analysis Curves in engineering Measurement Bridges Design and construction Analysis
2	A real-time bus dispatching policy to minimize headway variance Berrebi, Simon Jonas Youna 22 May 2014 (has links) Transit agencies include buffer time in their schedules to maintain stable headways and avoid bus bunching. In this work, a real-time holding mechanism is proposed to dispatch buses on a loop-shaped route, solely based on operating conditions in real-time. Holds are applied at the terminal station to minimize the expected variance of bus headways at departure. The bus-dispatching problem is formulated as a stochastic decision process. The optimality equations are derived and structural properties of the optimal policy are inferred by backward induction. The exact optimal holding policy is then found in closed form, as a function of the expected travel time of buses currently running. A simulation assuming stochastic operating conditions and unstable headway dynamics is performed to assess the expected average waiting time of passengers at stations. The proposed control strategy is found to provide lower passenger waiting time and better resiliency than methods recommended in the literature and used in practice. Bus Bunching Real-time Information Control Hold Holding Dispatching BRT Stochastic Optimization AVL, APC Prediction Schedule Headway Layover Control-point Terminal station Route Scheduling Bus lines Timetables Stochastic processes

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Behavior and Analysis of a Horizontally Curved and Skewed I-girder Bridge

A real-time bus dispatching policy to minimize headway variance