Matching Items (158)
Description
After describing the types of foundation systems employed for high rise buildings, this thesis discusses the process of foundation design for tall buildings as it is practiced today, including computer programs used in designing the foundations of high rise buildings. This thesis then presents the geotechnical in-situ and laboratory tests used to establish the parameters required for input to design analyses for high rise building foundations. This thesis subsequently describes the Construction Quality Assurance practices used in the construction of the foundations of high rise buildings. This thesis next presents several case histories detailing the foundation practices employed in the design and construction of modern high rise buildings. Finally, this thesis provides some concluding thoughts regarding the development of the geotechnical practices when designing and constructing high rise buildings.
ContributorsMohammad, Saeed Ishaq (Author) / Kavazanjian, Edward (Thesis director) / Zapata, Claudia (Committee member) / Houston, Sandra (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2013-05
Description
This dissertation investigates the potential for enzyme induced carbonate cementation as an alternative to Portland cement for creating building material from sand aggregate. We create a solution of urease enzyme, calcium chloride (CaCl2), and urea in water and added sand. The urease catalyzes the synthesis of carbonate from urea, and the carbonate then bonds with a dissociated calcium ion and precipitates from the solution as calcium carbonate (CaCO3). This precipitate can form small crystal bridges at contacts between sand grains that lock the sand grains in place. Using enzyme induced carbonate precipitation we created a cemented sand sample with a maximum compressive strength of 319 kPa and an elastic modulus of approximately 10 MPa. Images from the SEM showed that a major failure mechanism in the cemented samples was the delamination of the CaCO3 from the sand grains. We observed that CaCO3 cementation did not when solutions with high concentrations of CaCl2 and urea were used.
ContributorsBull, Michael Ryan (Author) / Kavazanjian, Edward (Thesis director) / Chawla, Nikhilesh (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor)
Created2014-05
Description
As green buildings become more popular, the challenge of structural engineer is to move beyond simply green to develop sustainable, and high-performing buildings that are more than just environmentally friendly. For decades, Portland cement-based products have been known as the most commonly used construction materials in the world, and as a result, cement production is a significant source of global carbon dioxide (CO2) emissions, and environmental impacts at all stages of the process. In recent years, the increasing cost of energy and resource supplies, and concerns related to greenhouse gas emissions and environmental impacts have ignited more interests in utilizing waste and by-product materials as the primary ingredient to replace ordinary Portland cement in concrete systems. The environmental benefits of cement replacement are enormous, including the diversion of non-recycled waste from landfills for useful applications, the reduction in non-renewable energy consumption for cement production, and the corresponding emission of greenhouse gases. In the vast available body of literature, concretes consisting activated fly ash or slag as the binder have been shown to have high compressive strengths, and resistance to fire and chemical attack. This research focuses to utilize fly ash, by-product of coal fired power plant along with different alkaline solutions to form a final product with comparable properties to or superior than those of ordinary Portland cement concrete. Fly ash mortars using different concentration of sodium hydroxide and waterglass were dry and moist cured at different temperatures prior subjecting to uniaxial compressive loading condition. Since moist curing continuously supplies water for the hydration process of activated fly ash mortars while preventing thermal shrinkage and cracking, the samples were more durable and demonstrated a noticeably higher compressive strength. The influence of the concentration of the activating agent (4, or 8 M sodium hydroxide solution), and activator-to-binder ratio of 0.40 on the compressive strengths of concretes containing Class F fly ash as the sole binder is analyzed. Furthermore, liquid sodium silicate (waterglass) with silica modulus of 1.0 and 2.0 along with activator-to-binder ratio of 0.04 and 0.07 was also studied to understand its performance in contributing to the strength development of the activated fly ash concrete. Statistical analysis of the compressive strength results show that the available alkali concentration has a larger influence on the compressive strengths of activated concretes made using fly ash than the influence of curing parameters (elevated temperatures, condition, and duration).
ContributorsBanh, Kingsten Chi (Author) / Neithalath, Narayanan (Thesis director) / Rajan, Subramaniam (Committee member) / Mobasher, Barzin (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2013-05
Finite element analysis of silicon thin films on soft substrates as anodes for lithium ion batteries
Description
The wide-scale use of green technologies such as electric vehicles has been slowed due to insufficient means of storing enough portable energy. Therefore it is critical that efficient storage mediums be developed in order to transform abundant renewable energy into an on-demand source of power. Lithium (Li) ion batteries are seeing a stream of improvements as they are introduced into many consumer electronics, electric vehicles and aircraft, and medical devices. Li-ion batteries are well suited for portable applications because of their high energy-to-weight ratios, high energy densities, and reasonable life cycles. Current research into Li-ion batteries is focused on enhancing its energy density, and by changing the electrode materials, greater energy capacities can be realized. Silicon (Si) is a very attractive option because it has the highest known theoretical charge capacity. Current Si anodes, however, suffer from early capacity fading caused by pulverization from the stresses induced by large volumetric changes that occur during charging and discharging. An innovative system aimed at resolving this issue is being developed. This system incorporates a thin Si film bonded to an elastomeric substrate which is intended to provide the desired stress relief. Non-linear finite element simulations have shown that a significant amount of deformation can be accommodated until a critical threshold of Li concentration is reached; beyond which buckling is induced and a wavy structure appears. When compared to a similar system using rigid substrates where no buckling occurs, the stress is reduced by an order of magnitude, significantly prolonging the life of the Si anode. Thus the stress can be released at high Li-ion diffusion induced strains by buckling the Si thin film. Several aspects of this anode system have been analyzed including studying the effects of charge rate and thin film plasticity, and the results are compared with preliminary empirical measurements to show great promise. This study serves as the basis for a radical resolution to one of the few remaining barriers left in the development of high performing Si based electrodes for Li-ion batteries.
ContributorsShaffer, Joseph (Author) / Jiang, Hanqing (Thesis advisor) / Rajan, Subramaniam D. (Committee member) / Peralta, Pedro (Committee member) / Arizona State University (Publisher)
Created2011
Description
Fluctuating flow releases on regulated rivers destabilize downstream riverbanks, causing unintended, unnatural, and uncontrolled geomorphologic changes. These flow releases, usually a result of upstream hydroelectric dam operations, create manmade tidal effects that cause significant environmental damage; harm fish, vegetation, mammal, and avian habitats; and destroy riverbank camping and boating areas. This work focuses on rivers regulated by hydroelectric dams and have banks formed by sediment processes. For these systems, bank failures can be reduced, but not eliminated, by modifying flow release schedules. Unfortunately, comprehensive mitigation can only be accomplished with expensive rebuilding floods which release trapped sediment back into the river. The contribution of this research is to optimize weekly hydroelectric dam releases to minimize the cost of annually mitigating downstream bank failures. Physical process modeling of dynamic seepage effects is achieved through a new analytical unsaturated porewater response model that allows arbitrary periodic stage loading by Fourier series. This model is incorporated into a derived bank failure risk model that utilizes stochastic parameters identified through a meta-analysis of more than 150 documented slope failures. The risk model is then expanded to the river reach level by a Monte Carlos simulation and nonlinear regression of measured attenuation effects. Finally, the comprehensive risk model is subjected to a simulated annealing (SA) optimization scheme that accounts for physical, environmental, mechanical, operations, and flow constraints. The complete risk model is used to optimize the weekly flow release schedule of the Glen Canyon Dam, which regulates flow in the Colorado River within the Grand Canyon. A solution was obtained that reduces downstream failure risk, allows annual rebuilding floods, and predicts a hydroelectric revenue increase of more than 2%.
ContributorsTravis, Quentin Brent (Author) / Mays, Larry (Thesis advisor) / Schmeeckle, Mark (Committee member) / Houston, Sandra (Committee member) / Arizona State University (Publisher)
Created2010
Description
Ordered buckling of stiff films on elastomeric substrates has many applications in the field of stretchable electronics. Mechanics plays a very important role in such systems. A full three dimensional finite element analysis studying the pattern of wrinkles formed on a stiff film bonded to a compliant substrate under the action of a compressive force has been widely studied. For thin films, this wrinkling pattern is usually sinusoidal, and for wide films the pattern depends on loading conditions. The present study establishes a relationship between the effect of the load applied at an angle to the stiff film. A systematic experimental and analytical study of these systems has been presented in the present study. The study is performed for two different loading conditions, one with the compressive force applied parallel to the film and the other with an angle included between the application of the force and the alignment of the stiff film. A geometric model closely resembling the experimental specimen studied is created and a three dimensional finite element analysis is carried out using ABAQUS (Version 6.7). The objective of the finite element simulations is to validate the results of the experimental study to be corresponding to the minimum total energy of the system. It also helps to establish a relation between the parameters of the buckling profile and the parameters (elastic and dimensional parameters) of the system. Two methods of non-linear analysis namely, the Newton-Raphson method and Arc-Length method are used. It is found that the Arc-Length method is the most cost effective in terms of total simulation time for large models (higher number of elements).The convergence of the results is affected by a variety of factors like the dimensional parameters of the substrate, mesh density of the model, length of the substrate and the film, the angle included. For narrow silicon films the buckling profile is observed to be sinusoidal and perpendicular to the direction of the silicon film. As the angle increases in wider stiff films the buckling profile is seen to transit from being perpendicular to the direction of the film to being perpendicular to the direction of the application of the pre-stress. This study improves and expands the application of the stiff film buckling to an angled loading condition.
ContributorsKondagari, Swathi Sri (Author) / Jiang, Hanqing (Thesis advisor) / Yu, Hongyu (Committee member) / Rajan, Subramaniam D. (Committee member) / Arizona State University (Publisher)
Created2010
Description
This thesis is part of a larger research project, conducted by Elizabeth Stallings Young, which aims to improve understanding about the factors controlling the process of MIDP and the interaction between the biochemical reactions and the hydrological properties of soils treated with MIDP. Microbially Induced Desaturation and Precipitation (MIDP) is a bio-geotechnical process by which biogenic gas production and calcite mineral bio-cementation are induced in the pore space between the soil particles, which can mitigate earthquake induced liquefaction (Kavazanjian et al. 2015). In this process substrates are injected which stimulate indigenous nitrate reducing bacteria to produce nitrogen and carbon dioxide gas, while precipitating calcium carbonate minerals. The biogenic gas production has been shown to dampen pore pressure build up under dynamic loading conditions and significantly increase liquefaction resistance (Okamura and Soga 2006), while the precipitation of calcium carbonate minerals cements adjacent granular particles together. The objective of this thesis was to analyze the recorded pore pressure development as a result of biogenic gas formation and migration, over the entire two-dimensional flow field, by generating dynamic pressure contour plots, using MATLAB and ImageJ software. The experiment was run in a mesoscale tank that was approximately 114 cm tall, 114 cm wide and 5.25 cm thick. Substrate was flushed through the soil body and the denitrifying reaction occurred, producing gas and correspondingly, pressure. The pressure across the tank was recorded with pore pressure sensors and was loaded into a datalogger. This time sensitive data file was loaded into a MATLAB script, MIDPCountourGen.m, to create pressure contours for the tank. The results from this thesis include the creation of MIDPContourGen.m and a corresponding How-To Guide and pore pressure contours for the F60 tank. This thesis concluded that the MIDP reaction takes a relatively short amount of time and that the residual pressure in the tank after the water flush on day 17 offers a proof of effect of the MIDP reaction.
ContributorsCoppinger, Kristina Marie (Author) / van Paassen, Leon (Thesis director) / Kavazanjian, Edward (Committee member) / Stallings-Young, Elizabeth (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Expansive soils in the United States cause extensive damage to roadways, buildings, and various structures. There are several treatment or methods of mitigation for these expansive soils. These treatments can be physical or chemical treatments that serve to provide more suitable building qualities for foundations and roadways alike. The main issue with expansive soils, is the volumetric variations, which are known as swelling and consolidation. These behaviors of the soil are usually stabilized through the use of lime solution, Portland Cement Concrete, and a newer technology in chemical treatments, sodium silicate solutions. Although the various chemical treatments show benefits in certain areas, the most beneficial method for stabilization comes from the combination of the chemical treatments. Lime and Portland cement concrete are the most effective in terms of increasing compressive strength and reduction of swell potential. However, with the introduction of silicate into either treatment, the efficacy of the treatments increases by a large amount lending itself more as an additive for the former processes. Sodium silicate solution does not lend itself to effectively increase the compressive strength of expansive soils. The sodium silicate solution treatment needs extensive research and development to further improve the process. A proposed experiment plan has been recommended to develop trends of pH and temperature and its influence on the effectiveness of the treatment. Nonetheless, due to the high energy consumption of the other processes, sodium silicate solution may be a proper step in decreases the carbon footprint, that is currently being created by the synthesis of Portland Cement Concrete and lime.
ContributorsMeza, Magdaleno (Author) / Zapata, Claudia (Thesis director) / Kavazanjian, Edward (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Current practice and a new technology for mitigating fugitive dust on construction sites are compared on the basis of economic, environmental and social impacts for this assessment. Fugitive dust can have serious health impacts, such as repertory illnesses and valley fever, on affected persons and is regulated by the Environmental Protection Agency and enforced by state and local agencies. Current practice consists of either relatively continuous application of potable water, a valuable resource, or application of expensive polymers, however, water application is considered the best available technology (BAT). The new technology, developed by the Center of Bio-medicated and Bio-inspired Geotechnics at Arizona State University, consists of application of Enzyme-Induced Carbonate Precipitate (EICP) to create an erosion-resistant crust. This crust is considered a "one and done" solution, until it is disturbed, however will last longer and stay more effective than quickly evaporating water. Future work will need to include how much disturbance is required to disturb the crust until ineffective towards mitigating fugitive dust. Results of the comparison show that a single EICP treatment produces 37 times less pollutants, uses 41 times less water and is 1.14 times cheaper than using water treatment to mitigate fugitive dust on a 7 acre site for 2 weeks (14 days). 14 days is the threshold at where EICP treatment becomes less expensive than water application for the purpose of mitigating fugitive dust. The EICP treatment benefits include lowering global warming inducing emissions, providing better air quality, becoming more cost effective, staying constantly effective to mitigate fugitive dust, and saving potable water.
ContributorsFabian, Aaron Jacob (Author) / Fox, Peter (Thesis director) / Kavazanjian, Edward (Thesis director) / Woolley, Miriam (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
This thesis was prepared by Tyler Maynard and Hayley Monroe, who are students at Arizona State University studying to complete their B.S.E.s in Civil Engineering and Construction Engineering, respectively. Both students are members of Barrett, the Honors College, at Arizona State University, and have prepared the following document for the purpose of completing their undergraduate honors thesis. The early sections of this document comprise a general, introductory overview of earthquakes and liquefaction as a phenomenon resulting from earthquakes. In the latter sections, this document analyzes the relationship between the furthest hypocentral distance to observed liquefaction and the earthquake magnitude published in 2006 by Wang, Wong, Dreger, and Manga. This research was conducted to gain a greater understanding of the factors influencing liquefaction and to compare the existing relationship between the maximum distance for liquefaction and earthquake magnitude to updated earthquake data compiled for the purpose of this report. As part of this research, 38 different earthquake events from the Geotechnical Extreme Events Reconnaissance (GEER) Association with liquefaction data were examined. Information regarding earthquake depth, distance to the furthest liquefaction event (epicentral and hypocentral), and earthquake magnitude (Mw) from recent earthquake events (1989 to 2016) was compared to the previously established relationship of liquefaction occurrence distance to moment magnitude. The purpose of this comparison was to determine if recent events still comply with the established relationship. From this comparison, it was determined that the established relationship still generally holds true for the large magnitude earthquakes (magnitude 7.5 or above) that were considered herein (with only 2.6% falling above the furthest expected liquefaction distance). However, this relationship may be too conservative for recent, low magnitude earthquake events; those events examined below magnitude 6.3 did not approach established range of furthest expected liquefaction distance. The overestimation of furthest hypocentral distance to liquefaction at low magnitudes suggest the empirical relationship may need to be adjusted to more accurately capture recent events, as reported by GEER.
ContributorsMonroe, Hayley (Co-author) / Maynard, Tyler (Co-author) / Kavazanjian, Edward (Thesis director) / Houston, Sandra (Committee member) / Civil, Environmental and Sustainable Engineering Program (Contributor) / Construction Engineering (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12