The primary objective of this research project was to perform live load tests on a bridge deck with GFRP reinforcement in the field under service conditions. The strains and deflections in the span reinforced with GFRP in the top mat were recorded under a series of truck crossings, and these were compared to the span reinforced with all steel bars under identical loading conditions, as well as design values and other test results. Transverse strains in the GFRP bars, girder distribution factors, girder bottom flange strains, dynamic load allowances, and weigh-in-motion gauge results were examined. From the live load tests, it was concluded that the bridge was designed conservatively for service loads, with measured strains, stresses, distribution factors, and impact factors below allowables and design values. The second objective was to monitor the construction of the bridge deck. To carry out this objective, researchers from Virginia Tech were on site during the bridge deck phase of the construction. The construction crews were observed while installing both the all-steel end span and the steel bottom/GFRP top end span. The installation of the GFRP bars went smoothly when compared to that of the steel bars. The workers were unfamiliar with the material at first, but by the end of the day were handling, installing, and tying the GFRP bars with skill. It was concluded that GFRP bars are an acceptable material in bridge deck applications with respect to constructibility issues. The third objective was to set up the long term monitoring and data collection of the bridge deck. Electrical resistance strain gauges, vibrating wire strain gauges, and thermocouples were installed in the deck prior to concrete casting to provide strain and temperature readings throughout the service life of the bridge. It was concluded that the span reinforced with GFRP was instrumented sufficiently for long-term health monitoring. / Master of Science

A study was undertaken to investigate the compressive capacity of a specific group of single angle members. A review of existing literature and techniques was presented. Laboratory compression tests were performed on 22 angle members of four different sizes and two different lengths. Additional tests were performed to determine the yield strength of the material. The results, normalized with respect to the yield stress, were tabulated and discussed. Two existing analytic models were used to attempt to predict the ultimate capacity of the test members. The first, an elastic method, was based upon the AISC combined stress equation. The second, an inelastic method, was developed by Mueller and Erzurumlu of Portland State University. Comparisons were made with the results of the test program. The results indicate that both analytic models give conservative predictions when pinned end conditions are assumed and unconservative results for fixed end conditions. For the test members with L/r ratios greater than 125, the elastic method results closely paralleled the test results but for the members with L/r ratios less than 125 the correlation was less consistent. The results of the inelastic technique closely paralleled the results of all the member tests.

Using the concepts of the institutional completeness of ethnic communities (Breton, 1964) and the gay male community (Lee, 1979) and more recently, 'deviant' organizational sophistication (Best and Luckenbill, 1982), this thesis examines the gay world argue that traditional concepts, in solitude or synthesis, cannot wholly illuminate the phenomenon of modern gay evolutionary development. Notions of subculture and community are inadequate tools by which to describe the complexity and cultural materials of a contemporary and emergent ethnographic unit of analysis: the gay world. Documentary and archival research, personal correspondence and in depth participant-observation have produced an array of historical and cultural materials and analyses of gay iconography, stereotypes, bars, and gay media. Structural features such as the politicization of homosexuality (the shift from rights lobbying to political and legal litigation) the politics of gender and AIDS, emergent age structures and the paradox of capitalist enterprise and liberation have also been examined. It is hypothesized that local gay communities (towns, cities, provinces, states and territories) do not themselves wholly depict this gay world. Rather, the communities and milieux are bound as the links of a chain, through often invisible networks of gay information, publishing, support services, recreation, leisure, unique artifacts and cultural materials. Many of these links exist world wide, traversing international customs, languages, traditions, legal systems, and concrete borders. These links show both variegation and similarity but most are based upon a unique fusion and specific unity, forged by a common prism of homosexual and gay oppression, identity, cu1ture, ideology, and more recently, a still emerging sense of gay identity. / Thesis / Master of Arts (MA)

This work has had the purpose to examine defects and the cause of crack growth during long term storage in rolled bars. The bars in question are rolled and stored at Ovako in Hofors. The problem is approached by theoretically examining the possibilities of hydrogen damage, room temperature creep and naturally occurring porosity. Seven bars of three steel type groups and with different rolling dates were selected and examined for defects with ultrasonic testing. Four of the bars show defects. Specimens containing the defects are cut out and grinded so that the defects can be examined in the scanning electron microscope and analyzed with energy dispersive x-ray spectroscopy. One of the specimens shows some form of cavity containing iron carbide. One of the others shows a surface with inclusions. The remaining two both shows inclusions and cracks that seem to originate from inclusions. The theoretical studies show that there are two types of hydrogen damage that could be in effect in the studied case and also that room temperature creep could facilitate but not cause crack growth and that porosity could serve as crack initiation points. Steps should be taken to minimize the problems mentioned above when they are suspected causes. Further examination of inclusions in different steel types should be made if considered a problem. / Detta arbete har haft syftet att undersöka defekter och orsaken till spricktillväxt under långtidsförvaring av spårvalsade stänger. Stängerna i undersökningen är valsade och lagrade hos Ovako i Hofors. Problemet är angripet genom att teoretiskt undersöka risken för väteskador, kryp i rumstemperatur och naturligt förekommande porositet. Sju stänger indelade i tre stålsortsgrupper och med olika valsningsdatum valdes ut och undersöktes med ultraljud. Fyra av stängerna visade på defekter. Prov innehållande dessa defekter blev utkapade och slipade så att defekterna kan bli undersökta i svepelektronmikroskop och analyserade med energidispersiv röntgenanalys. Ett av proverna visar på ett hålrum innehållande en järnkarbid. Ett av de andra proverna visar på en yta med inneslutningar. De två återstående proverna visar på inneslutningar och sprickor som verkar utgå från inneslutningar. De teoretiska studierna visar att det finns två typer av väteskador som är aktuella i det studerade fallet och även att kryp vid rumstemperatur kan underlätta spricktillväxt men inte orsaka den och att porositet kan tjäna som sprickinitieringsställen. Åtgärder för att minimera de nämnda problemen bör tas i fall där de är misstänkta orsaker. Ytterligare undersökningar av inneslutningsbilden bör göras om inneslutningar anses vara ett problem.

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An investigation on the application of hybrid glass fibre reinforced polymer (GFRP) and steel bars bars as longitudinal reinforcement for simple and continuous concrete beams is presented. Three simply and eleven multi-spans continuous reinforced concrete beams were constructed and tested to failure. Nine continuous and two simply supported beams were reinforced with a hybrid combination of both GFRP and steel re-bars at mid spans and internal support regions. In addition, two continuous concrete beams reinforced with either GFRP or steel bars and one simply supported beam reinforced with GFRP bars were tested as control beams. The beams were classified into two groups according to the reinforcement configurations. All specimens tested were 200 mm in width and 300 mm in depth. The continuous beams comprised of two equal spans, each of 2600 mm, while the simply supported beams had a span of 2600 mm. Unlike GFRP reinforced concrete beams, the hybrid and steel reinforced concrete beams failed in a favourable ductile manner and demonstrated narrow cracks and smaller deflections compared to the GFRP-reinforced control beam. The lower stiffness and higher deflection of GFRP reinforced concrete beams can be controlled and improved by the use of steel reinforcement in combination with GFRP re-bars. However, the ratio of GFRP to steel reinforcement is a key factor to ensure sufficient ductility and stiffness beyond the first cracking stage. The experimental results showed that the extent of moment redistribution in hybrid reinforced continuous beams depends mainly on the amount of hybrid reinforcement ratio in critical sections. Similar area of steel and GFRP bars in critical sections leads to limited moment redistribution whereas different amount of steel and FRP bars in critical sections leads to a remarkable moment redistribution. Design guidelines and formulas have been validated against experimental results of hybrid GFRP/steel reinforced concrete beams tested. The Yoon’s equation reasonably predicted the deflections of the hybrid beams tested whereas Qu’s model which is based on ACI 440.1R-15 underestimated the deflections of hybrid beams tested at all stage of loading after cracking. The ACI 440.2R-08 and Pang et al., (2015) equations reasonably predicted the sagging failure moment in most continuous hybrid reinforced concrete beams, whereas they underestimated the hogging flexural strength at failure of most hybrid continuous beams. On the other hand, the formulas proposed by Yinghao et al., (2013) was very conservative in predicting the failure moment at the critical sagging and hogging sections. On the analytical side, a numerical technique consisting of sectional analyses has been developed to predict the moment–curvature relationship and moment capacity of hybrid FRP/ steel reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. In addition, a two-dimensional nonlinear finite element model was proposed using ABAQUS package. The proposed model was validated against the experimental results of the beams tested in the present research. / Higher Education Institute in the Libyan Government

yes / This paper presents test results of six concrete beams reinforced with longitudinal carbon fiber reinforced polymer (CFRP) bars and without vertical shear reinforcement. All beams were tested under a two-point loading system to investigate shear behavior of CFRP reinforced concrete beams. Beam depth and amount of CFRP reinforcement were the main parameters investigated. All beams failed due to a sudden diagonal shear crack at almost 45°. A simplified, empirical expression for the shear capacity of FRP reinforced concrete members accounting for most influential parameters is developed based on the design-by-testing approach using a large database of 134 specimens collected from the literature including the beams tested in this study. The equations of six existing design standards for shear capacity of FRP reinforced concrete beams have also been evaluated using the large database collected. The existing shear design methods for FRP reinforced concrete beams give either conservative or unsafe predictions for many specimens in the database and their accuracy are mostly dependent on the effective depth and type of FRP reinforcement. On the other hand, the proposed equation provides reasonably accurate shear capacity predictions for a wide range of FRP reinforced concrete beams.

yes / This paper presents an analytical procedure based on the stiffness matrix method for deflection prediction of concrete structures reinforced with fiber reinforced polymer (FRP) bars. The variation of flexural stiffness of cracked FRP reinforced concrete members has been evaluated using various available models for the effective moment of inertia. A reduced shear stiffness model was also employed to account for the variation of shear stiffness in cracked regions. Comparisons between results obtained from the proposed analytical procedure and experiments of simply and continuously supported FRP reinforced concrete beams show good agreement. Bottom FRP reinforcement at midspan section has a significant effect on the reduction of FRP reinforced concrete beam deflections. The shear deformation effect was found to be more influential in continuous FRP reinforced concrete beams than simply supported beams. The proposed analytical procedure forms the basis for the analysis of concrete frames reinforced with FRP concrete members.

Yes / A numerical method for estimating the curvature, deflection and moment capacity of reinforced concrete beams strengthened with prestressed near-surface-mounted (NSM) FRP bars/strips is presented. A sectional analysis is carried out to predict the moment–curvature relationship from which beam deflections and moment capacity are then calculated. Based on the amount of FRP bars, different failure modes were identified, namely tensile rupture of prestressed FRP bars and concrete crushing before or after yielding of steel reinforcement. Comparisons between experimental results available in the literature and predicted curvature, moment capacity and deflection of reinforced concrete beams with prestressed NSM FRP reinforcements show good agreement. A parametric study concluded that higher prestressing levels improved the cracking and yielding loads, but decreased the beam ductility compared with beams strengthened with nonprestressed NSM FRP bars/strips.

Yes / The flexural performance of geopolymer concrete (GPC) T-beams reinforced longitudinally with GFRP bars under a four-point static bending test was investigated. Six full-scale simply supported T-beams were cast and tested; one control specimen was made with ordinary Portland cement concrete (OPCC), while the other five beams were made of geopolymer concrete. The G-GPC2 was designed to attain the same theoretical moment capacity as the G-OPCC6 control beam. The main parameters investigated were the reinforcement ratio of ρ_f/ρ_b= 0.75, 1.05, 1.12, 1.34 and 1.34 for G-GPC1, G-GPC2, G-GPC3, G-GPC4, and G-GPC5, respectively, and compressive strength of geopolymer concrete. Based on the results of the experiments, the ultimate strain of GPC did not show the same behaviour as that of OPCC, which affects the mode of failure. The beam capacity and deflection were, respectively, overestimated and underestimated using the ACI 440 2R-17 predictive equations.