Throughout the world, particularly in countries such as Canada, water crossings are a significant part of the infrastructure system. Since corrugated metal pipe culverts are an inexpensive choice, as well as hydraulically efficient, they are a very appealing option to designers. To ensure that the natural ecosystem is not adversely affected, culverts must be designed so that throughout the year fish can migrate upstream. Current design regulations are based on the average velocity within the culvert and the prolonged swimming speed of the fish species present. In order to examine the validity of this approach, a physical modeling study was undertaken using a circular CMP culvert. It was found that there is significant cross sectional area below average velocity, and that gravel embedment further increases this area. In addition, a technique was developed that produced very agreeable streamwise velocity predictions over a two dimensional cross section in the developed region.

Self consolidating concrete (SCC) is widely used in the construction industry. SCC is a high performance concrete with high workability and consistency allowing it to flow under its own weight without vibration and making the construction of heavily congested structural elements and narrow sections easier. Fiber reinforced polymer (FRP) reinforcement, with its excellent mechanical properties and non-corrosive characteristic, is being used as a replacement for conventional steel reinforcement. In spite of the wide spread of SCC applications, bond and flexural behaviour of SCC beams reinforced or prestressed with FRP bars has not been fully studied. Furthermore, the ACI 440.1R-06 equation for determining the development length of FRP bars is based on Glass FRP (GFRP) bars and may not be applicable for Carbon FRP (CFRP) bars. This research program included an experimental and analytical study to investigate the flexural and bond behaviour of SCC beams reinforced with FRP bars and SCC beams prestressed with CFRP bars. In the experimental phase, fifty-six beams were fabricated and tested. Sixteen of these beams were prestressed with CFRP bars and forty beams were reinforced with non-prestressed GFRP or CFRP bars. Four concrete batches were used to fabricate all the specimens. Three mixes were of self consolidating concrete (SCC) and one mix was of normal vibrated concrete (NVC). The test parameters for the non-prestressed beams were the concrete type, bar type and bar diameter, concrete cover thickness and embedment length while the test parameters for the prestressed beams were the concrete type and the prestressing level (30%, 45% and 60%). The transfer length of the prestressed CFRP bars was determined by means of longitudinal concrete strain profile and draw-in methods. All beams were tested in four-point bending to failure. Measurements of load, midspan deflection, bar slip if any at the beam ends, strain in reinforcing FRP bar at various locations, and strain in concrete at the beam midspan were collected during the flexural test. The concrete compressive strength at flexural tests of SCC mix-1, mix-2, and mix-3 were 62.1MPa, 49.6MPa and 70.9MPa, respectively and for the NVC mix was 64.5MPa. The material test results showed that SCC mixes had lower modulus of elasticity mechanical properties than the NVC mix. The modulus of elasticity of the SCC mixes ranged between 65% and 82% of the NVC mix. The modulus of rupture of the SCC mixes was 86% of the NVC mixes. The test results for beams prestressed with CFRP bars revealed that the variation of transfer length of CFRP bars in SCC versus their prestressing level was nonlinear. The average measured transfer lengths of 12.7mm diameter CFRP bars prestressed to 30%, 45% and 60% was found to be 25db, 40db, 54db, respectively. Measured transfer lengths of the 12.7mm diameter CFRP bar prestressed to 30% in SCC met the ACI440.4 prediction. However, as the prestressing level increased, the predicted transfer length became unconservative. At a 60% prestress level, the measured/prediction ratio was 1.25. Beams prestressed with CFRP bars and subjected to flexural testing with shear spans less than the minimum development length had local bar slippage within the transmission zone. Beams that experienced local bond slip, their stiffness was significantly decreased. A modification to the existing model used to calculate the transfer and development lengths of CFRP bars in NVC beams was proposed to account for the SCC. The test results for beams reinforced with FRP bars indicated that the average bond strength of CFRP bars in NVC concrete is about 15% higher than that of GFRP bars in NVC. The ACI 440.1R-06 equation overestimated the development length of the CFRP bars by about 40%, while CAN/CSA-S6-06 equation was unconservative by about 50%. A new factor of (1/1.35) was proposed to estimate the development length of the CFRP bars in NVC when the ACI440.1R-06 equation is used. Beams made from SCC showed closer flexural crack spacing than similar beams made from NVC at a similar loading. The deflection of beams made from SCC and reinforced with CFRP bars was found to be slightly larger than those made from NVC. The average bond stresses of GFRP and CFRP bars in SCC were comparable to those in NVC. However, FRP bars embedded in SCC beams had higher bond stresses within the uncracked region of the beams than those embedded in NVC beams. In contrast, FRP bars in SCC had lower bond stresses than FRP bars in NVC within the cracked region. The average bond strength of GFRP in SCC was increased by 15% when the concrete cover thickness increased from 1.0db to 3.0db. Cover thicknesses of 2db and 3db were found to be sufficient to prevent bond splitting failure of GFRP and CFRP bars in SCC, respectively. Bond splitting failure was recorded when the cover thickness dropped to 1.5db for the GRP bars and to 2.0db for the CFRP bars. An insignificant increase in average bond stress was found when the bar diameter decreased from 12.7mm to 6.3mm for the CFRP bars, and a similar increase occurred in GFRP bars when the bar diameter decreased from 15.9mm to 9.5mm. New models to calculate the development length of GFRP and CFRP bars embedded in SCC were proposed based on the experimental results. These models capture the average bond stress profile along the embedment length. A good agreement was found between the proposed model and the experimental results. Analytical modeling of the load-deflection response based on the effective moment of inertia (ISIS Canada M5) was unconservative for SCC beams reinforced with CFRP bars by 25% at ultimate loading. A new model for bond stress versus Ma/Mcr (applied moment to cracking moment) ratio was developed for GFRP and CFRP bars in SCC and for CFRP bars in NVC. These bond stress models were incorporated in a new rigorous model to predict the load-deflection response based on the curvature approach. The FRP bar extension and bond stress models were used to calculate the load-deflection response. With these models 90% of the calculated deflections were found to be within ± 15% of the experimental measured results for SCC beams reinforced with FRP bars. Analytical modeling of the load-deflection for NVC and SCC beams prestressed with CFRP bars are proposed done. The moment resistance was calculated using Sectional Analysis approach. The deflection was calculated using simplified and detailed methods. The simplified method was based on the effective moment of inertia while the detailed method was based on effective moment of inertia and effective centroid. The experimental results correlated well with the detailed method at higher loads range. This study provided an understanding of the mechanism of bond and flexural behaviour of FRP reinforced and prestressed SCC beams. The information presented in this thesis is valuable for designers using FRP bars as flexural reinforcement and also for the development of design guidelines for SCC structures.

This thesis investigates an influence of environmental variables (temperature and food availability) on development and growth of the first three nymphal stages of Ilyocoris cimicoides Linnaeus, 1758 Individuals were housed individually in experimental cages from eklosis into adulthood. Experiments were carried out in a combination of four different temperatures (17 ?, 19 ?, 22 ? and 25 ? C) and two different modes of food availability (full-fed every day, red-fed every other day) (in eight treatments). The temperature significantly influenced the length of nymphal development. According to our expectation, shortest development was achieved in individuals reared at 25° C. Development period was prolonged by decreasing temperatures. Unpredictably, the nymphs of the 3rd instar had longest development at the lowest temperatures (17 ? C) whereas nymphal development of the 1st and 2nd instars ran faster Both, the lowest- (17 ? C) as well as the highest used temperature (25 ? C) are probably very close to the temperature limits, that corresponds to the limits of postembryonic development. The optimum temperature for development was 22 ? C. Furthermore, it has been found that food availability should also significantly affect growth and development. Surprisingly, less mortality was observed in individuals reared in reduced feeding treatment, except the only case - nymphs reared in low temperature (19 ? C), where higher mortality was found in individuals reared at the same food availability.

Doctor of Philosophy / Department of Civil Engineering / Robert J. Peterman / Results of an extensive experimental program conducted to determine the material, bond characteristics, and time-dependent deformations of a proposed self-consolidating concrete (SCC) mixture for bridge girders are presented. This research program was completed in a three-step process. The first phase consisted of 15 full-scale, pretensioned SCC flexural specimens that were tested to evaluate their transfer and development lengths. These specimens included both single-strand and multiple-strand beams, as well as specimens designed to evaluate the so-called “top-strand" effect. The top-strand specimens, with more than 20 inches of concrete below the strand, were tested to evaluate the current American Association of State Highway Officials requirement of a 30% increase development length when the concrete below the strand is more than 12 inches. Strand end-slip measurements, used to estimate transfer lengths, indicated the proposed SCC mixture meets ACI and AASHTO requirements. In addition, flexural tests confirmed the proposed SCC mixture also meets current code requirements for development length. The second step was to evaluate the elastic shortening, creep, and shrinkage properties of the proposed SCC mixture for bridge girders. Four bridge girders with an inverted-T profile were used to measure these time-dependent deformations. In two of the specimens, the strands were tensioned to 75% of ultimate tensile strength (representing a girder that would be put into service). Strands of the other two specimens were left untensioned to evaluate shrinkage effect of the concrete alone. The shrinkage was then subtracted from the fully tensioned specimens and elastic shortening and creep were isolated after relaxation losses were calculated from code expressions. In addition, the fully tensioned specimens were used to determine transfer lengths of the prestressing strand. The final step in the program was to record strain measurements in actual bridge girders used in the field. Elastic shortening, creep, and shrinkage prestress loss results of the proposed SCC mixture were compared with current design equations. Instrumentation of seven pretensioned girders in a five-span bridge located in Cowley County, Kansas, was used to measure time-dependent deformations. Three of these girders utilized SCC, while the other four were cast with conventional concrete.

Reinforced masonry grouted using self-consolidating grout (SCG) is a relatively new and economically competitive option for construction, providing advantages such as reduced construction time, decreased noise and vibration, and reliable consolidation. However, SCG has different properties than conventional grout and its performance should be verified using current governing code requirements. The purpose of this research program was to determine the development length of spliced reinforcing bars in masonry grouted with SCG.Twelve masonry panels, four courses high and two and a half blocks wide, were constructed using 8-inch concrete masonry units, each with two pairs of vertically spliced #6 reinforcing bars. Six of the panels had splice lengths that met current code provisions to verify that the code requirements are adequate for use with SCG. The remaining panels had shorter splice lengths than required to investigate the possibility of shorter splices in SCG. The ultimate bond strengths were compared to the design requirement for a splice to develop 125% of the yield strength of the rein-forcing bars.All lap splices developed the required stress, including those with shorter lengths. This indicates that the current code provisions are adequate to determine the development length of reinforcement splices in masonry grouted with SCG and reinforced with #6 bars in the specific configurations tested. According to this study, a development length reduction factor may be viable when SCG is used in masonry.

The use of high compressive strengths in prestressed bridge girders can lower costs by allowing for longer spans, increased girder spacing, and smaller cross-sections. If high strength lightweight concrete (HSLWC) is used, these advantages are further enhanced due to the corresponding reduction in self-weight. Additional benefits can then be realized in the form of more traffic lanes, increased load capacity, smaller substructures, reduced crane capacity requirements, and lower shipping costs. Despite the possible economic savings, HSLWC has been used infrequently in prestressed bridge girder applications across the nation. While recent research has been performed to extend the applicability of current bridge design specifications to normal weight concretes with strengths as high as 18 ksi, little has been done by comparison with regards to HSLWC. The purpose of the research in this report was to assess whether current bridge design specifications for transfer length, development length, prestress loss, camber, and flexural capacity are satisfactory for use with fully-bonded, pretensioned flexural members consisting of HSLWC and to make recommendations for improvements where necessary. Twelve high strength pretensioned beams of variable unit weight (eight lightweight beams and four normal weight beams) and strand size (eight beams with 0.5-in. strand and four beams with 0.6-in. strand) were cast at the Thomas M. Murray Structural Engineering Laboratory at Virginia Tech. These beams were allowed to sit for a period of several months after fabrication while measurements were taken regarding transfer length, prestress loss, and camber. After this period, the beams were load tested to collect development length data, flexural data, and further data related to prestress loss. In addition to the laboratory cast beams, prestress loss and camber data from six full-size bridge beams (five lightweight beams and one normal weight beam) cast as part of a separate project at Virginia Tech was examined. Analysis of the results for all beams shows that with a few caveats, the current AASHTO LRFD Specifications and other design methods examined regarding the topics under consideration are satisfactory for use in the design of HSLWC pretensioned bridge girders with properties similar to those of the beams studied. / Ph. D.

The purpose of this study was to investigate the influence an increase in strand strength and the effect the as-cast vertical location had on transfer length, development length, and flexural strength and to resolve the discrepancies regarding the definition of the top-bar/strand effect. Two types of test specimens were fabricated and tested investigating each respective item. The increase in strand strength was found to influence transfer length, development length, and flexural strength, while the as-cast vertical location was only found to influence transfer length, and in turn development length. Contrary to the historical definition, the top-bar/strand effect was found to be more dependent on the amount of concrete cast above the strand than the amount below it, with transfer lengths showing a steady increase with a decrease in the amount of concrete cast above the strand. As a result of the findings of this study, a new transfer length equation was proposed and a previously proposed flexural bond length equation was recommended for use in lieu of the current code provisions. The current equations for flexural strength were found to give adequate estimates for flexural strength, although a decrease in ductility was noted. / Ph. D.

Encouraged by the performance of high performance normal weight composite girders, Virginia Department of Transportation has sought to exploit the use of high strength lightweight composite concrete (HSLWC) girders to achieve economies brought about by the reduction of dead loads in bridges. Transfer Length measurements conducted on two AASHTO Type IV HSLWC prestressed girders, resulted in an average transfer length of 17 inches, well below the AASHTO and ACI guidance. Two girders composed of HSLWC AASHTO Type II girders and a 48" x 8" normal weight 4000-psi concrete deck were produced. The HSLWC Type II girders were cast of concretes with a compressive strength of 6380 psi and unit weight of 114 pcf. Full scale testing of the girders was conducted to evaluate development length and flexural strength in HSLWC composite girders. Embedment lengths of five, six and eight feet were evaluated. Tests indicated a development length of about 72 inches, marginally below the ACI and AASHTO stipulation. Four of eight strands in the girders showed general bond failure nevertheless, the tested girders exceeded their theoretical flexural capacity by 24 to 30 percent. A third composite girder was cast of a high strength normal weight concrete (HSNWC) Type II girder, and topped with a 48" x 8" normal weight 4000-psi concrete deck. This girder was intended as a control specimen to contrast its test results with the HSLWC composite girders. The targeted compressive strength of both the HSLWC and HSNWC AASHTO beams was 8000 psi. The compressive strength of the HSNWC mixture, however, was about 8990 psi compared to 6380 psi for the HSLWC mixture. Prestress losses in HSLWC AASHTO Type IV girders monitored over a nine-month period were found to be less than those calculated using the ACI and PCI models. Furthermore, the ACI model indicated that the effective prestressess retained in the HSLWC girders in 30 year's time are greater than 50% of the specified tensile strength of the strands. / Master of Science

Master of Science / Department of Civil Engineering / Robert J. Peterman / With limited research being conducted solely on lightweight concrete prestressed bond and current development-length equations based on tests performed on normal-weight members, more investigation on lightweight concrete prestress bond is necessary. Additionally, the effects of water-reducing agents on normal-weight and lightweight concrete need further exploration. The aim of this study was to examine these areas using two locally available lightweight aggregates from Kansas and one from North Carolina to determine if lightweight prestressed concrete bridge girders are a useful alternative for the Kansas Department of Transportation. The lightweight concrete mixes developed were capable of attaining 5000 psi compressive strength in 16 hours and 7000 psi in 28 days. During the large block pull-out test, the average maximum force at pull-out and first observable slip was higher for the block cast with a three inch slump then the companion specimen poured at a nine-inch slump. During flexural testing, the two beams not reaching nominal moment capacity, KC-9 and STA-9, failed in compression without strand end slip. The moment capacity was considerably greater for three-inch slump members than the companion specimen placed with nine-inch slump concrete.

Cantilevered reinforced concrete columns with a lap splice of the longitudinal reinforcement near the base can induce high moment demands on the splice region when lateral loads are present on the structure. Code design specifications typically require a conservative splice length to account for these high moment demands and their consequences of bond failure. The required splice length is calculated as a function of required development length, which is a function of the bond between the reinforcement and the surrounding concrete, and a factor depending on the section detailing. However, the effects of concrete deterioration due to alkali silica reaction (ASR) and/or delayed ettringite formation (DEF) may weaken the bond of the splice region enough to overcome the conservative splice length, potentially resulting in brittle failure of the column during lateral loading. This thesis presents the following results obtained from an experimental and analytical program. * Fabrication of large-scale specimens of typical column splice regions with concrete that is susceptible to ASR/DEF deterioration * Measurement of the large-scale specimen deterioration due to ASR/DEF accelerated deterioration * Analytical model of the column splice region based on flexure theory as a function of the development length of the reinforcement and a factor to account for deterioration of the bond due to ASR/DEF * Experimental behavior of two large-scale specimens that are not influenced by premature concrete deterioration due to ASR/DEF (control specimens). This experimental data is also used to calibrate the analytical model. The conclusions of the research are that the analytical model correlates well with the experimental behavior of the large-scale control specimens not influenced by ASR/DEF. The lap splice region behaved as expected and an over-strength in the splice region is evident. To account for ASR/DEF damage, the analytical model proposes a reduction factor to decrease the bond strength of the splice region to predict ultimate performance of the region with different levels of premature concrete deterioration.