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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
681

Shear behaviour of continuous concrete beams reinforced with GFRP bars

Mahmoud, Karam Abdou Awad 26 November 2015 (has links)
Continuous beams represent main structural elements in most reinforced concrete (RC) structures such as parking garages and overpass bridges. Deterioration of such structures due to corrosion of steel reinforcement is common in North America. To overcome the corrosion problems, the use of fiber-reinforced polymer (FRP) bars and stirrups becomes a viable alternative to steel reinforcement. However, to date, the shear behaviour of FRP-RC continuous beams has not been explored yet. As such, the objective of this study is to investigate the shear behaviour of such beams. In this study, twenty four full-scale continuous concrete beams were constructed and tested. The test beams had rectangular cross section with 200-mm width and a height of 300, 550 or 850 mm and were continuous over two equal spans. The main investigated parameters were concrete strength, type and ratio of longitudinal reinforcement, type and ratio of transverse reinforcement and beam effective depth. Moreover, a 3-D nonlinear finite element model (FEM) was constructed to simulate the behaviour of FRP-RC continuous beams. The model was verified against the experimental results and validated against test results from previous studies. Then, the verified/validated model was used to conduct a parametric study to investigate the effect of a wide range of the parameters on the shear behaviour of GFRP-RC beams. The experimental and FEM results showed that shear-critical GFRP-RC continuous beams exhibited moment redistribution. Also, it was observed that increasing the concrete strength and the longitudinal reinforcement ratio increased the shear strength significantly. Moreover, the presence of GFRP stirrups significantly enhanced the shear strength of the tested beams. Regarding the size effect, test results showed that there was adverse or no size effect on the shear strength of GFRP-RC continuous beams when they failed in the interior shear span while beams failed in the exterior shear span exhibited clear size effect. Furthermore, a comparison between the test results and the provisions of the available models and FRP standards and design guidelines in North America revealed that these design provisions can be safely applied to continuous beams. / February 2016
682

Comparison of power grip and lateral pinch strengths between the dominant and non-dominant hands for normal Chinese male subjects ofdifferent occupational demand

Lau, Wai-shing, Vincent., 劉偉誠. January 2001 (has links)
published_or_final_version / Medical Sciences / Master / Master of Medical Sciences
683

Study of Mechanical Properties of PVA Fiber-Reinforced Concrete With Raman Spectroscopic Analysis

Annam, Ramyasree 01 May 2015 (has links)
The brittleness of concrete has always been a safety and economic issue of great concern. The low tensile strength of concrete is the cause of its intrinsic brittle nature. This is critical considering the amount of concrete used for the construction of highways, buildings, and other facilities. The mechanical properties of concrete must be improved to provide upgraded construction. Crack resistant and durable concrete has always been a major goal for engineers. Many approaches have been tried to make concrete a better construction material. Fiber reinforcement is an approach which has been shown to improve the quality and durability of concrete. The focus of this research is to develop a mix design of fiber reinforced concrete and then test these materials for both compressive and tensile strength after casting into cubes. The effect of polyvinyl alcohol fibers on the mechanical properties of concrete was also studied. The impacts of moisture and the stress applied on the fibers were determined using Raman spectroscopy.
684

Preliminary normative standards for muscular strength assessment using free-weights and Paramount/Cybex machines / Title on approval sheet: Creating standards for muscular strength assessment using free-weights and Paramount machines

Kesler, Douglas D. January 2005 (has links)
Preliminary normative standards are a tool clinical exercise specialists and health fitness instructors can use when interpreting muscular strength testing results. However, a challenge for professionals is evaluating an individual's one-repetition maximum (IRM) and relating that to others of the same age and gender, because there are no preliminary normative standards for 1RMs available when testing via free-weights and machines.This study conducted at Ball State University, Adult Physical Fitness Laboratory, examined results of muscular strength testing in order to obtain the normative muscular strength of adults. The purpose was to develop preliminary normative standards for strength of adults and to compare the 1RM weight an individual lifts between free-weights, Paramount, and Cybex machines. Seventy-nine healthy men and women between 18 and 79 years of age participated in the study. Subjects were tested on free weights, Paramount, and Cybex machines.Test results revealed preliminary normative standards for 1RM on free weights. Individuals were categorized in three age groups for the free-weight bench press and the Cybex (free-weight) Leg Press. The 18-23 year olds obtained a IRM mean (± Standard Deviation (SD)) of 200.6 + 32.8 lbs and 83.6 ± 18.5 lbs for men and women, respectively, for the free-weight bench press. The 43-59 year olds obtained a 1RM mean of 149.2 ± 41.8 lbs and 71.3 ± 8.6 lbs and the 60-79 year olds had a 1RM mean of 119.5 + 30.0 Ibs and 61.6 ± 15.6 lbs for men and women, respectively, for the free-weight bench press. The 18-23 year olds obtained a 1RM Cybex (free-weight) leg press mean of 484.9 + 58.0 lbs and 234.3 ± 67.5 lbs for men and women, respectively. The 43-59 year olds were able to obtain 1RM means of 444.4 + 84.9 lbs and 254.5 ± 51.7 lbs and the older subjects (60-79 years old) were able to obtain 1RM mean of 390.7 ± 98.6 lbs and 230.3 ± 76.6 lbs for men and women, respectively. Results were also documented in relative values by the amount of weight pushed divided by body weight for better comparison of individuals. Subjects generally lifted more weight on the Cybex (free-weight) leg press compared to the Cybex (machine) leg press. All subjects (N=79) had a mean and standard deviation of 294.9 + 87.7 lbs for the Cybex (machine) leg press (1RMs) and 343.4 ± 123.4 lbs on the Cybex (free-weight) leg press (1RMs). There was a significant difference between the Cybex (free-weight) leg press and the Cybex leg press (p<.001). The correlation for these two types of lifts was r=0.88. There was a significant difference between the free-weight bench press and the Paramount seated chest press (p<.001). The correlation for between the two types of lifts was r=0.93. / School of Physical Education, Sport, and Exercise Science
685

Investigation of wet paper cohesive properties

Guerrero Serrato, Alexander 09 July 2008 (has links)
Wet web paper cohesive properties behave in a similar way than tensile strength properties. The result was obtained using an unique apparatus developed by the IPST, which allows the cohesive strength determination for different wet web solids content. With the results a linear relation can be established between the cohesive strength index (obtained with the splitting apparatus) and the tensile strength index (obtained with the Instron). The splitting apparatus results can be used to calculate strain based on the work of Osterberg.
686

Evaluation of high strength lightweight concrete precast, prestressed bridge girders

Dunbeck, 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.
687

Hand function in children and in persons with neurological disorders : aspects of movement control and evaluation of measurements /

Svensson, Elisabeth, January 2009 (has links)
Diss. (sammanfattning) Umeå : Umeå universitet, 2009. / Härtill 4 uppsatser.
688

A comparison between in vivo and in vitro bond strengths of a glass ionomer cement a clinical study : a thesis submitted in partial fulfillment ... restorative dentistry, operative ... /

Tyler, Michael W. January 1986 (has links)
Thesis (M.S.)--The University of Michigan, 1986. / Also issued in print.
689

A comparison between in vivo and in vitro bond strengths of a glass ionomer cement a clinical study : a thesis submitted in partial fulfillment ... restorative dentistry, operative ... /

Tyler, Michael W. January 1986 (has links)
Thesis (M.S.)--The University of Michigan, 1986. / eContent provider-neutral record in process. Description based on print version record.
690

Hand function in children and in persons with neurological disorders aspects of movement control and evaluation of measurements /

Svensson, Elisabeth, January 2009 (has links)
Diss. (sammanfattning) Umeå : Univ., 2009.

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