M.Ing. / Design parameters for ferritic type stainless steel structural members do not exist and is needed. This study attempts to find design parameters for ferritic type stainless steel compression elements. The ferritic type stainless steel under consideration in this study is Type 3CR12 corrosion resisting steel, which is a modified Type 409 stainless steel. The purpose of this study was to determine the limiting web width-to-thickness and flange width-to-thickness ratios for the prevention of local buckling in axially loaded hotrolled Type 3CR12 corrosion resisting steel columns. Experimental data was obtained in an ongoing study on the limiting width-to-thickness ratios for elements in compression. No conclusion on this aspect can be reached at this stage of the investigation

Thesis. (M.Tech. (Dept. of Civil Engineering and Building, Faculty of Engineering and Technology)) -- Vaal University of Technology, 2011. / This research focused on the structural performance of Fibre Reinforced Polymer (FRP) re-bars in structural foundation compared to steel reinforcement re-bars. The corrosion of steel re-bars is the main reason of deterioration of reinforced concrete. However, use of FRP re-bars as alternative reinforcement will address the deterioration of reinforced concrete. Carbon and Glass Fibre Reinforced Polymer re-bars were used as reinforcing bars and traditional steel reinforced concrete was used as the reference. Thirty six specimens of reinforced concrete bases were tested for flexural capacity at different ages. The simulation of Soil Bearing Pressure of this study was derived from the model of beam finite length on elastic foundation. The foundation base was treated as a beam while the soil was modelled as series of timber elements acting as springs. The mathematical model to reflect the model was as documented by Timoshenko (1976:18) and Den Hartog (1952:160). Results showed that stress in the steel re-bars of reinforced concrete was higher than that of Carbon Fibre Reinforced Polymer (CFRP) and Glass Fibre Reinforced Polymer (GFRP) re-bars by 227 MPa (5.99 percent) and 284 MPa (7.61 percent), respectively. The stress in CFRP re-bars was 57 MPa or 1.53 percent higher compared to GFRP re-bars of FRP reinforced concrete. Furthermore, the experimental ultimate moments of CFRP and GFRP reinforced concrete foundation – bases on the 28th day were 23.917 kNm (79.0 percent) and 23.529 kNm (77.7 percent) higher than the theoretical ultimate moments, respectively. However, steel reinforced concrete foundation – bases had the higher calculated deflection than FRP reinforced concrete. With high resistance to corrosion as a property, FRP re-bars appeared to be a better alternative reinforcement to steel in corrosion in an aggressive environment. / Vaal University of Technology

Graduation date: 1998

Thesis (M.E.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 27, 2007) Includes bibliographical references.

No / This paper presents a numerical method for estimating the curvature, deflection and moment capacity of hybrid FRP/steel reinforced concrete beams. A sectional analysis is first carried out to predict the moment-curvature relationship from which beam deflection and moment capacity are then calculated. Based on the amount of FRP bars, different failure modes were identified, namely tensile rupture of FRP bars and concrete crushing before or after yielding of steel reinforcement. Comparisons between theoretical and experimental results of tests conducted elsewhere show that the proposed numerical technique can accurately predict moment capacity, curvature and deflection of hybrid FRP/steel reinforced concrete beams. The numerical results also indicated that beam ductility and stiffness are improved when steel reinforcement is added to FRP reinforced concrete beams. (C) 2015 Elsevier Ltd. All rights reserved,

No description available.

The primary objective of this research was to experimentally investigate material and bond properties of three different types of fiber reinforced polymer (FRP) bars, and determine their effect on the design of a bridge deck using FRP bars as the top mat of reinforcement. The properties evaluated include the tensile strength, modulus of elasticity, bond behavior, and maximum bond stress. The experimental program included 47 tensile tests and 42 beam end bond tests performed with FRP bars. Tensile strength of the bars from the tensile testing ranged from 529 MPa to 859 MPa. The average modulus, taken from all the testing, for each type of bar was found to range from 40 GPa to 43.7 GPa. The maximum bond stress from the beam end bond tests ranged from 9.17 MPa to 25 MPa. From the tests, design values were found in areas where the properties investigated were related. These design values include design tensile strength, design modulus of elasticity, bond coefficient for deflection calculations, bond coefficient for crack width calculations, and development length. The results and conclusions address design concerns of the different types of FRP bars as applied in the top mat of reinforcement of a bridge deck. A secondary objective was to evaluate the disparity in results between direct pullout tests, and beam end bond tests. Results from the experimentally performed beam end bond test were compared to previous literature involving the direct pullout tests. Results from the performed beam end bond tests were higher than all of the literature using direct pullout results. No recommendations were given on the disparity between the two test methods. / Master of Science

Master of Science / Department of Civil Engineering / Sunanda Dissanayake / Speed management has been a challenge, particularly in places where high-speed highways pass through. Due to high rate of fatalities and low budgets available, it is therefore necessary to identify low-cost effective approaches in reducing speeds. Optical Speed Bar (OSB) treatment is one such technique. This research makes an attempt to evaluate the effectiveness of OSBs in reducing approach speeds on two-lane, rural highways approaching small communities. Speed data were collected and analyzed “before” and “after” periods at five sites. Effectiveness of OSBs was evaluated using changes in mean and 85th percentile speeds under different categories by considering all vehicles, vehicle classification (two axles vs. more than two axles), day of the week (weekdays vs. weekends), and time of day (daytime vs. nighttime), as well as proportions exceeding posted speed limit, using t-test mean speeds, F-test for analysis of variance, and Z-test for proportions of vehicles exceeding posted speed limit between “before” and “after” datasets. Even though motorists were found to slow down on the approaches, in response to speed zones, speeding was noted. “Before” speed data indicated higher speeds than desired at the sites. The 85th percentile speeds were between 50 and 63 mph while the posted speed limits on the approaches were 45 mph at four sites, and the 85th percentile speed was about 42 mph at one site with an approach posted speed limit of 30 mph. The “before” degrees of noncompliance were up to 90 % of free-flowing vehicles at the sites. Speed data analysis showed significant reductions in speeds at ends of OSBs at four test sites. Mean and 85th percentile speeds and standard deviations were found reduced in the after periods. Percent reductions in mean speeds were between 1.2 and 8.2 %, with 85th percentile reductions between 3.2 and 8.9 %. At one site, no notable change in mean and 85th percentile speeds occurred at the end of OSBs, but significant increases in standard deviations were noted. Speed reductions were higher for two-axle vehicles, during the daytime and on weekdays with few exceptions. Results of the study showed, as other previous studies did, OSBs may have some minor effects on vehicle speeds. The study provides an indication that it may be possible to create safety improvements as result of using OSBs on the approach to a rural community. However, magnitude of speed reductions was generally small, though the reductions were statistically significant at the 95% confidence level. Because of the non-consistence of the magnitude of speed reductions at the test sites, no conclusion can be drawn as to how much OSB treatment reduced speeds. These results were based on “after” periods up to five months. Therefore, further study would be required to determine whether these safety improvements are sustained over an even longer time period. Even though minor speed reductions occurred, speeds observed at the sites were still higher than the posted speed limits, indicating OSBs were not effective enough in providing the desired speed limit compliance. Additional studies would be helpful to identify combinations of countermeasures, for instance OSBs and other techniques, effective in providing speed limit compliance.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy