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Multiscale modeling and design of ultra-high-performance concreteEllis, Brett D. 13 January 2014 (has links)
Ultra-High-Performance Concretes (UHPCs) are a promising class of cementitious materials possessing mechanical properties superior to those of Normal Strength Concretes (NSCs). However, UHPCs have been slow to transition from laboratory testing to insertion in new applications, partly due to an intuitive trial-and-error materials development process. This research seeks to addresses this problem by implementing a materials design process for the design of UHPC materials and structures subject to blast loads with specific impulses between 1.25- and 1.5-MPa-ms and impact loads resulting from the impact of a 0.50-caliber bullet travelling between 900 and 1,000 m/s. The implemented materials design process consists of simultaneous bottom-up deductive mappings and top-down inductive decision paths through a set of process-structure-property-performance (PSPP) relations identified for this purpose. The bottom-up deductive mappings are constructed from a combination of analytical models adopted from the literature and two hierarchical multiscale models developed to simulate the blast performance of a 1,626-mm tall by 864-mm wide UHPC panel and the impact performance of a 305-mm tall by 305-mm wide UHPC panel. Both multiscale models employ models at three length scales – single fiber, multiple fiber, and structural – to quantify deductive relations in terms of fiber pitch (6-36 mm/revolution), fiber volume fraction (0-2%), uniaxial tensile strength of matrix (5-12 MPa), quasi-static tensile strength of fiber-reinforced matrix (10-20 MPa), and dissipated energy density (20-100 kJ/m²). The inductive decision path is formulated within the Inductive Design Exploration Method (IDEM), which determines robust combinations of properties, structures, and processing steps that satisfy the performance requirements. Subsequently, the preferred material and structural designs are determined by rank order of results of objective functions, defined in terms of mass and costs of the UHPC panel.
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Evaluation of high strength lightweight concrete precast, prestressed bridge girdersDunbeck, Jennifer 08 April 2009 (has links)
This thesis evaluates the use of High Strength Lightweight Concrete (HSLW) in bridge girders for the I-85 Ramp "B" Bridge crossing SR-34 in Cowetta County, Georgia. This bridge consisted of four spans; all girders were constructed using lightweight expanded slate aggregate. Spans 2 and 3 had a design strength of 10,000 psi, and span 2 was chosen for this research. The BT-54 girders were 107 ft 11½ inches in length. The prestressing strands used in these girders were 0.6 in diameter, grade 270, low relaxation strands. Material properties and member properties were tested.
All 5 girders of span 2 were instrumented with vibrating wire strain gages at midspan, as well as with DEMEC inserts for transfer length measurements and with a deflection measurement system. Transfer length measurements found the transfer length of the girders to be 23% less than the values suggested by AASHTO and ACI equations. The deflection measurements showed 4.26 inches of camber at 56-days while the girders were stored at Standard Concrete Products. The camber measurements matched theoretical predictions within 5%. Mechanical property tests found the concrete to be within all design requirements.
A stiffness, load test was performed on each of the 5 girders at Standard Concrete Products. The average stiffness value of 8.428 x 106 kip ft2 is recommend for use by GDOT engineers in designing the deck and road profile.
This thesis discusses all short term findings from construction to the end of storage. A later report will address long term issues such as creep and shrinkage, as well as the performance of the girders as part of the bridge.
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Nondestructive evaluation of prestressed concrete structures by means of acoustic emissions monitoringXu, Jiangong. Barnes, Robert W., January 2008 (has links)
Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references (p. 202-209).
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Vacuum assisted resin transfer molding in the repair of reinforced concrete bridge structuresCauthen, Stephen Michael. January 2008 (has links) (PDF)
Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed May 30, 2008; title from title screen. Includes bibliographical references (p. 84-86).
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Reflective cracking of flexible pavements literature review, analysis models,and testing methods /Loria-Salazar, Luis Guillermo. January 2008 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2008. / "May, 2008." Includes bibliographical references (leaves 155-160). Online version available on the World Wide Web.
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Repair and strengthening of Pre-1970 reinforced concrete corner beam-column joints using CFRP compositesEngindeniz, Murat. January 2008 (has links)
Thesis (Ph.D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008. / Committee Co-Chair: Kahn, Lawrence F.; Committee Co-Chair: Zureick, Abdul-Hamid; Committee Member: Armanios, Erian A.; Committee Member: Gentry, Russell T.; Committee Member: Leon, Roberto T.
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Improving corrosion resistance of post-tensioned substructures emphasizing high performance grouts /Schokker, A. J. January 1999 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 306-312). Available also in a digital version from Dissertation Abstracts.
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Laboratory performance of highway bridge girder anchorages under hurricane induced wave loading /Lehrman, Jora. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 86-88). Also available on the World Wide Web.
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In-situ testing of a carbon/epoxy IsoTruss reinforced concrete foundation pile /Richardson, Sarah, January 2006 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2006. / Includes bibliographical references (p. 121-122).
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Seismic damage avoidance design of warehouse buildings constructed using precast hollow core panels : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Civil Engineering in the University of Canterbury /Abdul Hamid, N. H. January 2006 (has links)
Thesis (Ph. D.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.
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