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You searched for +publisher:"Texas A&M University" +contributor:("Sideris, Petros"). Showing records 1 – 3 of 3 total matches.

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Texas A&M University

1. Pillay Thulaseedharan, Nandhu. Impact of Truck Platooning on Texas Bridges.

Degree: MS, Civil Engineering, 2020, Texas A&M University

United States trucking industry has an annual revenue output of $725 billion and is expected to grow by over 40 percent by 2045. The biggest challenges faced by the industry is the ever-increasing oil prices and the shortage of drivers to meet the growing demands. Truck platooning provides an efficient solution for both the challenges, which can be incorporated by equipping the existing inventory with modern sensors and systems. Platooning of trucks is the process by which two or more trucks move together along highways, maintaining a constant close space between them also allowing for significant fuel savings. The scope of this study is to research the potential impacts of truck platoons on the Texas bridge inventory. Bridges are one of the major elements of the highway infrastructure. Texas has the largest bridge inventory in the USA with over 55,000 bridges (more than 40 percentage older than 40 years). Due to the large inventory under consideration, a subset of bridges most likely support future truck platoons was selected (6,550 bridges). For each of these structures estimated truck platoon load ratings were calculated according to the original design methodology (allowable stress, load factor, or load and resistance factor) using NBI data elements along with assumptions from prior studies. The obtained load ratings from the older structures were then standardized to the load and resistance factor rating method. Then the bridges were prioritized considering the effects of the bridge condition. This identified the structures that require the earliest attention. In total, six different trucks at four different spacings under two- and three-truck platoons were analyzed as a part of the research. In addition, a cost benefit analysis is also performed with respect to truck platoons and bridges for better understanding of the benefits. Overall conclusions were drawn regarding the sensitivity of the original design methodology, bridge span length, truck type, truck spacing and number of trucks within a platoon on the bridge prioritization. In addition, a secondary benefit of the study is that a framework is presented for other bridge owners to prioritize their bridges that may be subjected to truck platoon or other heavy vehicle loading. Advisors/Committee Members: Yarnold, Matthew (advisor), Haque, Mohammed (committee member), Sideris, Petros (committee member).

Subjects/Keywords: Bridges; Structural Engineering; Transportation; Platoons; Automation; TxDOT; Truck Platoon

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APA (6th Edition):

Pillay Thulaseedharan, N. (2020). Impact of Truck Platooning on Texas Bridges. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/191819

Chicago Manual of Style (16th Edition):

Pillay Thulaseedharan, Nandhu. “Impact of Truck Platooning on Texas Bridges.” 2020. Masters Thesis, Texas A&M University. Accessed April 15, 2021. http://hdl.handle.net/1969.1/191819.

MLA Handbook (7th Edition):

Pillay Thulaseedharan, Nandhu. “Impact of Truck Platooning on Texas Bridges.” 2020. Web. 15 Apr 2021.

Vancouver:

Pillay Thulaseedharan N. Impact of Truck Platooning on Texas Bridges. [Internet] [Masters thesis]. Texas A&M University; 2020. [cited 2021 Apr 15]. Available from: http://hdl.handle.net/1969.1/191819.

Council of Science Editors:

Pillay Thulaseedharan N. Impact of Truck Platooning on Texas Bridges. [Masters Thesis]. Texas A&M University; 2020. Available from: http://hdl.handle.net/1969.1/191819


Texas A&M University

2. Gulati, Jasmine. Reliability-Based Optimum Inspection Planning for Components Subjected to Fatigue Induced Damage.

Degree: MS, Civil Engineering, 2018, Texas A&M University

The degradation of metallic systems under cyclic loading is prone to significant uncertainty. This uncertainty in turn affects the reliability in the prediction of residual lifetime and the subsequent decision regarding the optimum inspection and maintenance schedules. In particular, the experimental data on the evolution of fatigue-induced cracks shows significant scatter stemming from initial flaws, metallurgical heterogeneities, and randomness in material properties like yield stress and fracture toughness. The objective of this research is to improve the reliability-based optimal inspection planning of metallic systems subjected to fatigue, taking into account the associated uncertainty. To that end, this research aims to address the two main challenges faced in developing a credible reliability-based framework for lifecycle management of fatigue-critical components. The first challenge is to construct a stochastic model that can adequately capture the nonlinearity and uncertainty observed in the crack growth histories. The second one involves presenting a computationally efficient strategy for solving the stochastic optimization associated with optimum maintenance scheduling. In order to fulfill these objectives, a Polynomial Chaos (PC) representation is constructed of fatigue-induced crack growth process using a database from a constant amplitude loading experiment. The PC representation relies on expanding the crack growth stochastic process on a set of random basis functions whose coefficients are estimated from the experimental database. The probabilistic model obtained is then integrated into a reliability framework that minimizes the total expected life-cycle cost of the system subjected to constraints in terms of time to inspections, and the maximum probability of failure defined by the limit state function. Lastly, an efficient and accurate optimization strategy that uses surrogate models is suggested to solve the stochastic optimization problem. The sensitivity of the optimum solution to the level of risk is also examined. This research aims to provide a decision support tool for informed decision-making under uncertainty in the life-cycle planning of systems subjected to fatigue failure. Advisors/Committee Members: Noshadravan, Arash (advisor), Sideris, Petros (committee member), Castaneda-Lopez, Homero (committee member).

Subjects/Keywords: Fatigue; Reliability; Life-cycle optimization; Maintenance; Polynomial Chaos Expansions

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Gulati, J. (2018). Reliability-Based Optimum Inspection Planning for Components Subjected to Fatigue Induced Damage. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/174132

Chicago Manual of Style (16th Edition):

Gulati, Jasmine. “Reliability-Based Optimum Inspection Planning for Components Subjected to Fatigue Induced Damage.” 2018. Masters Thesis, Texas A&M University. Accessed April 15, 2021. http://hdl.handle.net/1969.1/174132.

MLA Handbook (7th Edition):

Gulati, Jasmine. “Reliability-Based Optimum Inspection Planning for Components Subjected to Fatigue Induced Damage.” 2018. Web. 15 Apr 2021.

Vancouver:

Gulati J. Reliability-Based Optimum Inspection Planning for Components Subjected to Fatigue Induced Damage. [Internet] [Masters thesis]. Texas A&M University; 2018. [cited 2021 Apr 15]. Available from: http://hdl.handle.net/1969.1/174132.

Council of Science Editors:

Gulati J. Reliability-Based Optimum Inspection Planning for Components Subjected to Fatigue Induced Damage. [Masters Thesis]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/174132


Texas A&M University

3. Salehi Najafabadi, Mohammad. Nonlinear Modeling, Dynamic Analysis, and Experimental Testing of Hybrid Sliding-Rocking Bridges.

Degree: PhD, Civil Engineering, 2020, Texas A&M University

Hybrid sliding-rocking (HSR) bridge columns were recently developed in the context of Accelerated Bridge Construction (ABC) for seismic regions. These columns incorporate end rocking joints, intermediate sliding joints, and unbonded posttensioning to introduce self-centering and energy dissipation into the substructure. This dissertation intends to further the overall understanding of the dynamic behavior of HSR columns, improve their seismic design, and examine their construction feasibility. First, a modeling strategy is proposed to enable the nonlinear dynamic analysis of HSR columns. For this purpose, four finite element formulations are developed, namely: (1) a gradient inelastic force-based (FB) element formulation; (2) an HSR FB element formulation; (3) a continuous multi-node truss element formulation; and (4) a zero-length constraint element formulation. These element formulations are then implemented in an structural analysis software to validate the capability of the developed strategy in capturing the data from the past tests on HSR columns. Once validated, the developed modeling strategy is used to evaluate the effects of several design variables on the seismic performance of HSR columns through multiple nonlinear static and time history analyses. The examined design variables directly/indirectly represent: (i) sliding joint distribution, (ii) coefficient of friction at sliding joints, (iii) duct and duct adaptor dimensions, and (iv) posttensioning system properties. Subsequently, a number of recommendations are made about the effective design of HSR columns. The effects of vertical excitation and near-fault ground motions on the response of HSR columns are also examined, showing their minimal impacts. The above computational investigations are followed by an extensive experimental program to validate the performance of HSR columns with improved design and to examine their actual response under various loading conditions. This program includes testing of four half-scale HSR columns under uniaxial lateral loading, combined uniaxial lateral and torsional loading, and biaxial lateral loading. The columns under uniaxial lateral loading are tested in both cantilever and fixed-fixed conditions. The test results show the low damageability of the HSR columns under displacements representing 950- and 2475-year earthquakes. Selected tests under uniaxial lateral loading are also simulated using the proposed modeling strategy and improvements are suggested accordingly. Advisors/Committee Members: Sideris, Petros (advisor), Bracci, Joseph M (committee member), Mander, John B (committee member), Haque, Mohammaed E (committee member), Liel, Abbie B (committee member).

Subjects/Keywords: Accelerated Bridge Construction; precast concrete; rocking column; seismic performance; nonlinear analysis; finite element; computational modeling; experimental testing; seismic design

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Salehi Najafabadi, M. (2020). Nonlinear Modeling, Dynamic Analysis, and Experimental Testing of Hybrid Sliding-Rocking Bridges. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/191848

Chicago Manual of Style (16th Edition):

Salehi Najafabadi, Mohammad. “Nonlinear Modeling, Dynamic Analysis, and Experimental Testing of Hybrid Sliding-Rocking Bridges.” 2020. Doctoral Dissertation, Texas A&M University. Accessed April 15, 2021. http://hdl.handle.net/1969.1/191848.

MLA Handbook (7th Edition):

Salehi Najafabadi, Mohammad. “Nonlinear Modeling, Dynamic Analysis, and Experimental Testing of Hybrid Sliding-Rocking Bridges.” 2020. Web. 15 Apr 2021.

Vancouver:

Salehi Najafabadi M. Nonlinear Modeling, Dynamic Analysis, and Experimental Testing of Hybrid Sliding-Rocking Bridges. [Internet] [Doctoral dissertation]. Texas A&M University; 2020. [cited 2021 Apr 15]. Available from: http://hdl.handle.net/1969.1/191848.

Council of Science Editors:

Salehi Najafabadi M. Nonlinear Modeling, Dynamic Analysis, and Experimental Testing of Hybrid Sliding-Rocking Bridges. [Doctoral Dissertation]. Texas A&M University; 2020. Available from: http://hdl.handle.net/1969.1/191848

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