Browsing by Subject "shear"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
Item Characterization of design parameters for fiber reinforced polymer composite reinforced concrete systems(Texas A&M University, 2004-09-30) Aguiniga Gaona, FranciscoCorrosion of steel reinforcement in concrete structures results in significant repair and rehabilitation costs. In the past several years, new fiber reinforced polymer (FRP) reinforcing bars have been introduced as an alternative to steel reinforcing bars. Several national and international organizations have recently developed standards based on preliminary test results. However, limited validation testing has been performed on the recommendations of these standards. High variability of the tensile properties, degradation of tensile strength, direct shear capacity, predicted deflections due to creep, cracking behavior of FRP-reinforced concrete flexural members, bond behavior and development length, and effects of thermal expansion on cracking of FRP reinforced concrete have all been reported, but are areas that need further investigation and validation. The objective of this study is to evaluate the characteristics of glass FRP reinforcing bars and provide recommendations on the design and construction of concrete structures containing these bar types with regard to the areas described. The recently developed ACI 440 design guidelines were analyzed and modifications proposed.Item Evaluation of the shear design provisions of ACI 523.4R for autoclaved aerated concrete members(2009-05) Abu Yousef, Ali Emad; Klingner, R. E.; Bayrak, Oguzhan, 1969-Autoclaved aerated concrete (AAC) is a lightweight cellular building material. In Spring 2008, an experimental study was conducted at The University of Texas at Austin to evaluate the load-deflection behavior and capacity of six different factory-reinforced AAC lintel groups. The results the test program are used to evaluate the shear design provisions of ACI 523.4R “Guide for Design and Construction with AAC Panels”.Item Tenderness Assessment of Beef Steaks from US Foodservice and Retail Establishments Using Warner-Bratzler Shear and Consumer Sensory Panel Ratings(2012-02-14) Guelker, MilesBeef retail steaks from establishments in twelve US cities and beef foodservice steaks from establishments in five US cities were evaluated using Warner-Bratzler shear and consumer sensory panels. Postmortem aging times for retail establishments ranged from 1 to 358 d with a mean of 20.5 d, and those from foodservice establishments aging times ranged from 9 to 67 d with an average of 15.9 d. For retail, top blade had the lowest (P < 0.05) WBS values, while cuts from the round top round and bottom round had the highest (P < 0.05) WBS values. Top loin and ribeye steaks had the lowest (P < 0.05) WBS values compared to top sirloin foodservice steaks. Retail top blade steaks received the highest (P < 0.05) ratings by consumers for overall like, tenderness level, like tenderness, juiciness level, and like juiciness; and foodservice top loin steaks received the highest (P < 0.05) for tenderness level, like tenderness, flavor level, juiciness level, and like juiciness. USDA quality grade did have an effect on foodservice ribeye and top sirloin steaks for sensory panels. Prime foodservice ribeye steaks were rated highest (P < 0.05) for overall like, like tenderness, tenderness level, like juiciness, and juiciness level, whereas ungraded ribeye steaks were rated lowest (P < 0.05) for like tenderness and tenderness level. Ungraded foodservice top sirloin steaks were rated highest (P < 0.05) for overall like, like tenderness, like flavor, and like juiciness. Additional improvements to reduce the range of tenderness levels are necessary to increase consumer acceptability.Item The Effects of Fluid Flow On Shear Localization and Frictional Strength From Dynamic Models Of Fault Gouge During Earthquakes(2013-12-02) Bianco, RonaldThis thesis explores the effects of fluid flow on shear localization and frictional strength of fault gouge through the use of a coupled 2-phase (pore fluid-grain) Finite Difference-Discrete Element Numerical model. The model simulates slip at earthquake velocities (~1m/s) in a fluid saturated gouge-filled fault. We find three types of shear behavior: (I) distributed shear, (II) random internal localization, and (III) boundary localization. Each shear type is dependent on the applied shear velocity, V, effective confining stress, N, and internal permeability, k. Through quantitative analysis of the positions and magnitude of localized shear bands, we show under which conditions the presence of and transitions between these shear types will occur. During shear, fluid pressure deviations, delta P, are generated by dilation and compaction cycles. The fluid effects on the system are more pronounced in simulations with higher V and lower N and k. Relative to the dry experiments, fluid saturated systems have an increased localization toward the boundaries of the gouge layer (type III), and no occurrence of distributed (type I) shear. Systems with lower N and k show liquefaction events. Liquefaction events originate from increases in fluid pressure, delta P, around force chains between grains. Once delta P, the high pressures weaken the frictional forces between grains and destroy force chains. Shear then occurs at essentially zero friction until a new grain configuration recreates force chains. A reduction in mean friction is seen for systems with large liquefaction events (without inclusion of thermal pressurization), which could introduce a new mechanism in low friction faults. We also find that systems undergoing different types of shear will all trend toward type (III) shear following a liquefaction event.