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Effects Of Slurry Type On Drilled Shaft Strength, Cesar Quesada Garcia
Effects Of Slurry Type On Drilled Shaft Strength, Cesar Quesada Garcia
USF Tampa Graduate Theses and Dissertations
The main objective of this research is to identify how the strength of drilled shafts is affected by the use of various types of drill slurry. When concrete is placed in drilled shafts it flows out radially and a laitance interface forms creating a crease on the backside of the reinforcement cage due to the laitance trapped in concrete flowing around the rebar. This can cause concrete to not fully encapsulate the steel making the shafts prone to corrosion and the strength of the cover concrete is locally reduced. Over the past 9 years 58, 42-inch diameter shafts have been …
Electrochemical Methods To Characterize Drilled Shaft Deficiencies, Sarah Jo Mobley
Electrochemical Methods To Characterize Drilled Shaft Deficiencies, Sarah Jo Mobley
USF Tampa Graduate Theses and Dissertations
In recent years drilled shafts have become the preferred foundation method for marine bridges. Typically, the drilled shaft is selected over traditional driven piles due to soil strata encountered, construction economy, increased lateral stiffness requirements, and/or vibration control considerations. The most critical component in drilled shaft construction is borehole stabilization. Wall sloughing or groundwater inclusion can have devastating effects on the strength of the finished shaft however recent research has shown that the materials, more specifically the slurry, used to accomplish stabilization may be having a negative impact on the durability of the finished product. This thesis investigates the durability …
Time Dependent Effect Of Drilling Slurries On Side Shear Resistance Of Drilled Shafts, Warren Allen
Time Dependent Effect Of Drilling Slurries On Side Shear Resistance Of Drilled Shafts, Warren Allen
USF Tampa Graduate Theses and Dissertations
Drilled shafts are cylindrical deep foundations constructed by casting fluid concrete into an excavated hole. These elements rely largely on side shear resistance generated by their substantial diameters and lengths to effectively transfer loads. Therefore, an exceptional concrete to soil interface is essential for proper performance of these structures. The FDOT preferred stabilization fluid, bentonite slurry, has been proven to degrade this interface with increased exposure time due to filter cake formation. For this reason, slurry exposure time has been limited to 36 hours by FDOT. Alternately, polymer slurries do not form a filter cake but rather stabilize excavations through …
The Evaluation Of Hybrid Slurry Resulting From The Introduction Of Additives To Mineral Slurries, Kyle Douglas Yeasting
The Evaluation Of Hybrid Slurry Resulting From The Introduction Of Additives To Mineral Slurries, Kyle Douglas Yeasting
USF Tampa Graduate Theses and Dissertations
Drilled shaft construction often requires the use of drill slurry to maintain borehole stability during excavation and concreting. While drill slurry may be composed of fluids ranging from air to petroleum, drilled shaft construction typically makes use of water based drilling fluids. Although clean water may be utilized as a drilling fluid, a premixed slurry consisting of water, minerals, and/or polymers is more commonly used. Florida Department of Transportation (FDOT) specifications require the use of mineral slurry for all primary structures. The slurry resists the intrusion of groundwater, slows the outward migration of drilling fluid from the excavation, and aids …