Browsing by Author "Van de Lindt, John W., committee member"
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Item Open Access Reliability-based lifetime performance analysis of long-span bridges(Colorado State University. Libraries, 2010) Wu, Jun, author; Chen, Suren, 1973-, advisor; Van de Lindt, John W., committee member; Heyliger, Paul Roy, 1958-, committee member; Sakurai, Hiroshi, committee memberLong-span bridges generally serve as the significant hub in the transportation system for normal transportation and critical evacuation paths when any disaster happens. Thus, the safety and serviceability of long-span bridges are related to huge economic cost and safety of thousands of lives. The objective of this research is to establish a general framework to evaluate the lifetime performance of long-span bridges through taking account of more realistic load situations, such as traffic flow and wind environment. After some background information is introduced in Chapter 1, Chapter 2 covers the modeling of stochastic traffic flow for the bridge infrastructure system in a more realistic way by using the Cellular Automaton model. Based on the detailed information of individual vehicles of the stochastic traffic flow, the general framework to study Bridge/Traffic/Wind dynamic performance is developed in Chapter 3. Chapter 3 and Chapter 4 also report the results of the bridge's serviceability under normal and extreme loads events, respectively. In Chapter 5, the scenario-based fatigue model is further developed based on the dynamic framework developed in Chapter 3. Finally, the reliability-based analysis is conducted in Chapter 6 to study the fatigue damage caused by the coupling effects among bridge, traffic flow and wind throughout the bridge's service life.Item Open Access Structural engineering masters level education framework of knowledge for the needs of initial professional practice(Colorado State University. Libraries, 2012) Balogh, Zsuzsa Eniko, author; Criswell, Marvin E., advisor; Grigg, Neil S., committee member; Van de Lindt, John W., committee member; Siller, Thomas J., committee member; De Miranda, Michael Anthony, committee memberFor at least the last decade, engineering, civil engineering, along with structural engineering as a profession within civil engineering, have and continue to face an emerging need for "Raising the Bar" of preparedness of young engineers seeking to become practicing professional engineers. The present consensus of the civil engineering profession is that the increasing need for broad and in-depth knowledge should require the young structural engineers to have at least a Masters-Level education. This study focuses on the Masters-Level preparedness in the structural engineering area within the civil engineering field. It follows much of the methodology used in the American Society of Civil Engineers (ASCE) Body of Knowledge determination for civil engineering and extends this type of study to better define the portion of the young engineers preparation beyond the undergraduate program for one specialty area of civil engineering. The objective of this research was to create a Framework of Knowledge for the young engineer which identifies and recognizes the needs of the profession, along with the profession's expectations of how those needs can be achieved in the graduate-level academic setting, in the practice environment, and through lifelong learning opportunities with an emphasis on the initial five years experience past completion of a Masters program in structural engineering. This study applied a modified Delphi method to obtain the critical information from members of the structural engineering profession. The results provide a Framework of Knowledge which will be useful to several groups seeking to better ensure the preparedness of the future young structural engineers at the Masters-Level.Item Open Access Valuable utilization of spray dryer ash and its performance in structural concrete(Colorado State University. Libraries, 2010) Namagga, Carolyne Alex, author; Atadero, Rebecca A., advisor; Ozbek, Mehmet E., committee member; Van de Lindt, John W., committee memberThis research focuses on the valuable utilization of Spray Dryer Ash (SDA) and investigates its performance in concrete for structural and transportation applications. Based on the challenges associated with coal ash (including SDA) and the economic costs linked to cement production, this research seeks to provide an environmentally friendly and more cost effective concrete product by utilizing SDA in partial replacement of cement in concrete. Cement production is a rather expensive venture and yet there is an abundance of coal ash that is disposed of in landfills that could be utilized positively. The fineness and low carbon content properties of SDA/ Class C fly ash provide potential benefits of increased strength (compressive and bond) and durability (freeze-thaw and corrosion) when used in concrete. With the exception of high sulfur content, SDA exhibits very excellent properties that are closely related to Class C fly ash and Portland cement. The addition of Spray Dryer Ash in non-air entrained concrete provided a general increase in its strength. The compressive strength test results indicate that replacing proportions of cement with SDA would provide improved strength and a most cost effective solution. When utilized within optimal limits of 25-35% replacement, SDA presents reasonable benefits to compressive and bond strength. The utilization of SDA provided modest benefits when used in certain proportions and at the very least it did not seem to degrade the properties much. It produced a negligible effect on the freeze-thaw durability of the concrete while an increase in the SDA provided an increased corrosion resistance and a reduced corrosion rate in concrete. Based on the results of this research, SDA has great potential for its utilization as a structural material in transportation infrastructures.