Self-compacting concrete has soon been around for a decade. Recently the prefabrication industry has started to use this fairly new concrete type in larger scales, mainly because of its distinctive properties.  There are still certain areas that need to be thoroughly examined, such as bond capacity. There have been very few studies regarding shear capacity due to the fact that the procedure is complicated. This report will highlight a method to examine the shear capacity of different surfaces that have been prewetted as well as non-prewetted surfaces. The surface areas follow BBK 04’s and Eurocode 2’s demand for surface roughness.  A smooth surface will be completed in order to confirm if the different shapes influence the bond strength by shear stress or not.                        The purpose of this essay is to measure the bond strength within the shear capacity as well as examine the impact it has on surface roughness and treatment for shear bond. The method used to identify the shear capacity is called L-shaped Push-Off Test. The dimension of the object was selected with the help of a previous research paper. The Sand-Patch method is predominantly used to measure the surface roughness.  The results showed no difference between the demands of surfaces of BBK04 and Eurocode 2 considering the shear capacity. However the non-prewetted surface was measured with the highest shear capacity value. Apart from the shear strength, deformation was measured in both vertical and horizontal direction and it was clearly shown that the vertical deformation was measured to be ten times higher than the horizontal deformation.  There was no difference between the BBK 04 and Eurocode 2 considering the vertical deformation. However the difference occurred on the horizontal direction between BBK 04 and Eurocode 2 where the specimens of Eurocode 2 received three times higher deformation compared to BBK 04. The conclusion can be drawn that the surface roughness of BBK 04 would be more suitable than eurocode2 considering deformation.      The overall result was that the surface treatment with the demands of BBK 04 and Eurocode 2 showed minor difference after being measured with the Push-Off Test method. This has been confirmed with the estimated shear capacity (1.2 MPa). The results revealed that the treatment of surface could be made in either way, brush or rake. As a conclusion the assessment of the shear strength showed that Eurocode 2's demand is too strict comparing demands of BBK 04. / Att bestämma vidhäftningen mellan prefabricerade element och senare pågjutning på arbetsplats är viktigt. Självkompakterande betong är en betongtyp som flera prefabricerade företag börjat använda på grund av dess goda egenskaper. Dock finns några oklarheter som behöver utredas vidare, exempelvis vidhäftningskapaciteten vid pågjutning. I och med införandet av Eurokod blev det större krav på skrovligheten jämfört med tidigare krav i BBK 04. För självkompakterande betong kan det vara svårt att få till en skrovlighet enligt både BBK och speciellt Eurokod. För undersökning av vidhäftningskapacitet kopplat till draghållfastheten finns beprövade metoder som följer svensk standard. Dock finns ingen svensk standard för vidhäftningsprov för skjuvhållfastheten, bland annat på grund av att för få undersökningar har utförts och att provnings-utförandet är mer komplext. Syftet med denna undersökning är att jämföra olika mätmetoder för att mäta skjuvspänningar för vidhäftningen mellan prefabelement och pågjutningsbetong samt att också undersöka olika metoder för att mäta ytjämnheten. Målet är att identifiera skjuvkapaciteten i vidhäftningen samt få reda på vilken påverkan ytjämnhet och ytbehandling har för vidhäftningen. Detta för att utvärdera om Eurokod 2:s hårdare krav på skrovlig yta är nödvändig jämfört med BBK 04 med avseende på skjuvning. Ytor som ska jämföras är avdragen yta och yta som uppfyller BBK 04:s samt Eurokod 2:s  krav på skrovlig yta. Mätmetoder för skrovlighet ska undersökas för att senare utvärderas och användas i undersökningen.  Förutom dessa ytor som normalt förvattnas ska även en yta som följer BBK 04:s krav på skrovlig yta utan förvattning undersökas om förvattning har någon positiv inverkan på vidhäftningen. Den mätmetod som valdes för att identifiera skjuvhållfastheten var L-formad Push-Off-metod, vilket dimensionerades med hjälp av en referensundersökning. Provkroppen tillverkades i Strängbetongs fabrik i Kungsör och innan pågjutningen utfördes mättes ytjämnheten på vidhäftningsytan med hjälp av Sand-Patch-metoden. För att bekräfta validiteten hos Sand-Patch-metoden användes också en annan mätmetod, så kallad Profilmall. Efter att ytorna var uppmätta och pågjutningen hårdnat skickades provkropparna till CBI Betonginstitut för skjuvhållfasthetsprovning samt tryckprovning. Resultaten från undersökningen visade att inga större skillnader i skjuvhållfasthet mättes mellan Eurokods och BBKs krav på ytjämnhet, men det visade sig att den obehandlade ytan klarade av högst skjuvhållfasthet. Alla värden var betydligt högre än vad både Eurokod och BBK 04 anger för hållfasthetsklassen C45/55. Under provningstillfället upptäcktes sprickbildning vid 85 kN både i den befintliga betongen samt vid pågjutningen på de tunnaste delarna, för samtliga provförsök. Utöver skjuvhållfastheten mättes även deformationer såväl vertikalt som horisontellt och det framgick tydligt i resultatet att vertikala deformationerna var mer än tio gånger större än de horisontella. Ingen skillnad mellan BBK och Eurokod kunde tydas vid vertikala deformationer, dock vid horisontella deformationer mättes Eurokod till tre gånger större horisontella deformationer jämfört med BBK. Detta tyder på att BBKs krav på skrovlighet är bättre än Eurokod ur deformationssynvinkel Med denna undersökning som grund kan tillverkarna välja att avstå från Eurokod 2:s hårdare krav på skrovlig yta och fortsätta att behandla ytan enligt BBK 04. I och med detta menar författarna att Eurokod 2:s hårdare krav på skrovlig yta inte är nödvändig jämfört med BBK 04 med avseende på skjuvning (vidhäftning), vilket var det primära målet för undersökningen.

As part of an international cooperative research program, the U.S. Geological Survey (USGS) and researchers from the National Gas Hydrate Program (NGHP) of India are studying the physical properties of sediment recovered during the NGHP-01 cruise conducted offshore India during 2006. Here we report on index property, acoustic velocity, and triaxial shear test results for samples recovered from the Krishna-Godavari Basin. In addition, we discuss the effects of sample storage temperature, handling, and change in structure of fine-grained sediment. Although complex, sub-vertical planar gas-hydrate structures were observed in the silty clay to clayey silt samples prior to entering the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI), the samples yielded little gas post test. This suggests most, if not all, gas hydrate dissociated during sample transfer. Mechanical properties of hydrate-bearing marine sediment are best measured by avoiding sample depressurization. By contrast, mechanical properties of hydrate-free sediments, that are shipped and stored at atmospheric pressure can be approximated by consolidating core material to the original in situ effective stress.

Hydro One, a major distribution of electricity in Ontario, has reported that approximately 16,000 of the wood utility poles in its network of two million poles have been damaged by woodpeckers. With a cost of replacement of approximately $4000 per pole, replacing all affected poles is an expensive enterprise. Previous research conducted at UW attempted to quantify how different levels of woodpecker damage affected the pole strength. In the course of this research, some shear failures were observed. Utility poles being slender cantilevered structures, failures in shear are not expected. The objectives of this study were to determine the effective shear strength of wood utility poles and to determine the reliability of wood utility poles under different configurations, including poles that had been damaged by woodpeckers. An experimental programme was developed and conducted to determine the effective shear strength of wood poles. Red Pine wood pole stubs were used for this purpose. The stubs were slotted with two transverse half-depth cuts parallel to one another but with openings in opposite directions. A shear plane was formed between these two slots. The specimens were loaded longitudinally and the failure load was recorded and divided by the failure plane area to determine the shear strength. The moisture content of each specimen was recorded and used to normalize each data point to 12 % moisture content. The experimental study showed that the mean shear strength of the Red Pine specimens adjusted to 12 % moisture content was 2014 kPa (COV 47.5 %) when calculated using gross shear area, and 2113 kPa (COV 40.5 %) when calculated using net area. The shear strength of full-size pole specimens can be represented using a log-normal distribution with a scale parameter of λ = 0.5909 and a shape parameter of ζ = 0.5265. iii The reliability of Red Pine wood utility poles was determined analytically. A structural analysis model was developed using Visual Basic for Applications in Excel and used in conjunction with Monte Carlo simulation. Statistical distribution parameters for wind loads and ice accretion for the Thunder Bay, Ontario region were obtained from literature. Similarly, statistical data were obtained for the modulus of rupture and shear strength from previous research conducted at UW as well as the experimental programme conducted in this research. The effects of various properties on reliability were tested parametrically. Tested parameters included the height of poles above ground, construction grade, end- of-life criterion, and various levels of woodpecker damage. To evaluate the results of the analysis, the calculated reliability levels were compared to the annual reliability level of 98 % suggested in CAN/CSA-C22.3 No. 60826. Results of this reliability study showed that taller poles tend to have lower reliability than shorter ones, likely due to second-order effects having a greater influence on taller poles. The Construction Grade, a factor which dictates the load factors used during design, has a significant impact on the reliability of wood utility pole, with poles designed using Construction Grade 3 having a reliability level below the 98 % threshold. Poles designed based on Construction Grade 2 and 3 having reached the end-of-life criterion (60 % remaining strength) had reliability below this threshold whilst CG1-designed pole reliability remained above it. Wood poles with exploratory- and feeding-level woodpecker damage were found to have an acceptable level of reliability. Those with nesting-level damage had reliability below the suggested limits. Poles with feeding and nesting damage showed an increase in shear failure. The number of observed shear failure depended on the orientation of the damage. Woodpecker damage with the opening oriented with the neutral axis (i.e., the opening perpendicular to the direction of loading) produced a greater number of shear failure compared to woodpecker damage oriented with the extreme bending fibres.

No description available.

The compression behaviour, shear strength characteristics, and material properties of dense slurries and soft settled beds of natural fine-grained sediments were studied experimentally. Slurries of varying initial density, initial height, and pore fluid salinity were settled one-dimensionally, by self-weight, in the laboratory. Settling behaviour was studied in terms of slurry appearance, particle segregation, height of surface versus time, sediment surface and element settlement rates, and the redistribution of sediment with respect to height and time. Consolidation behaviour was studied in terms of sediment compressibility and pore fluid flow. Shear strength was examined "in situ" and elated to the parameters effective stress and specific volume. Instruments and techniques were developed to facilitate the measurement of low effective stresses, low strengths, and high specific volumes. A small scale sediment sampler was developed and used in an attempt to study the arrangement of particles within soft sensitive beds. The experimental results revealed numerous fundamental reasons why theoretical models of settling and consolidation are unsatisfactory when applied to dense flocculated slurries and beds of high specific volume, respectively. For the sediment studied, well-defined compressibility and shear strength relationships were observed. Pore fluid flow relationships were non-unique at high specific volumes. The compression behaviour of slurries was found to have a rational basis in terms of electrochemical forces and degrees of particle association. The experimental results are relevant to engineering practice. Recommendations are made regarding future research.

Plate girders are fabricated in situations where standard structural shapes do not possess the required strength necessary to carry applied loads. In many instances, plate girders are tapered so that the resistance to bending is proportional to the bending moment, creating cost effective, aesthetically pleasing structures. The AISC 2010 Specifications accurately predict the flexural capacity of tapered plate girders but recent research has suggested that the required shear strength is overly conservative. The researchers postulate that the required shear strength is overly conservative due to an effect known as modified shear that has been neglected from the AISC 2010 Specifications but has been suggested by several authors. This research investigates both analytically and experimentally, tapered member ultimate shear strength considering a “modified” and “unmodified” applied shear approach. A new design formula introduced by Lee et al. (2008) will be used in conjunction with the AISC 2010 Specification in making ultimate shear strength comparisons. A total of 12 specimens are tested to failure, ten tapered and two prismatic built-up plate girders.

Bermudagrass (Cynodon dactylon L.) is often used for athletic fields due to its wear tolerance and recuperative ability. Studies were conducted May 2007 through November 2008 in Lexington, Kentucky. The cultivars ‘Quickstand’, ‘Tifway’, ‘Riviera’, and ‘Yukon’ grown in a sand-based medium were used to investigate differences in wear tolerance and shear strength. Trinexapac-ethyl (TE) was applied at label rates and frequencies or untreated. Overseeding treatments were perennial ryegrass (Lolium perenne L.) at 0, 612, and 1225 kg PLS ha-1. Traffic treatments were applied with a Brinkman traffic simulator 3 d wk-1 August through October. Shear tests were conducted using the Clegg shear tester once wk-1 for the same period. The main effect of cultivar was significant (p Quickstand=Yukon) and overseeding at the medium and high rates. Significant differences (p Tifway =Yukon (2007) and with Riviera ≥ Quickstand > Tifway = Yukon (2008). Significant differences (p0.05) in either year for traffic tolerance or shear strength.

As an abundant sedimentary rock, shale is widely used as construction material around the world. However, shale is a fissile and laminated material and is therefore subject to deterioration due to environmental and chemical forces (i.e., weathering), which is possible to cause high maintenance cost on associated structures and failures of earth slopes and embankments. However, currently, there is lack of efficient method to monitor the weathering process of shale. This thesis uses several shale samples collected from the commonwealth of Kentucky to study the deformation and shear behaviors of weathered compacted shale. A new electrical approach was developed to access the deformation behavior of shale. The long term deformation behaviors, such as collapse and swell can be predicted from specific electrical parameters. The critical state theory was used to describe the shear behavior of weathered compacted shale. Some findings observed by previous researchers were confirmed, and new empirical equations were provided to estimate the shear strength parameters of weathered compacted shale.

No description available.

In this study, the relationship between soil suction and shear strength parameters of compacted METU campus clay were investigated at different moisture contents. Soil samples were tested at optimum moisture content (i.e. w=20.8%), at dry side of optimum moisture content (i.e. w=14.8%, 16.8%, 18.8%) and at wet side of optimum moisture content (i.e. w=22.8%, 24.8%, 26.8%). Direct shear tests were performed to measure shear strength parameters (c&#039 / , &amp / #934 / &#039 / ) and soil suctions were measured by filter paper method after direct shear tests. These relationships were also investigated on soaked samples. The trends for suction, angle of internal friction and cohesion, which change on the dry side and wet side of optimum moisture content, were analyzed. The compacted METU campus clay gains granular soil fabric at the dry side of optimum moisture content. As moisture content increases, cohesion increases up to optimum moisture content and then decreases. But angle of internal friction decreases as moisture content increases. Soaking affects the samples more which are on the dry side of optimum moisture content. The soil suction (total suction and matric suction) affects the shear strength, and an increase in soil suction increases the shear strength.