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- Title
- Analytical evaluation of marine concrete pile repairs.
- Creator
- Saleh, Zaher A. Abou., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
The purpose of the thesis is to determine and compare the performance characteristics of marine piles corroded by chloride diffusion and repaired by several different methods for both uncracked and cracked concrete and to determine their structural integrity. The long-term objective is the comparison of the analytical values with those from an on-going experimental evaluation. The time for chloride concentration reach the threshold value that initiates corrosion in the reinforcement has been...
Show moreThe purpose of the thesis is to determine and compare the performance characteristics of marine piles corroded by chloride diffusion and repaired by several different methods for both uncracked and cracked concrete and to determine their structural integrity. The long-term objective is the comparison of the analytical values with those from an on-going experimental evaluation. The time for chloride concentration reach the threshold value that initiates corrosion in the reinforcement has been determined by Fick's law, extended to 2-D and 3-D chloride diffusion, for (a) uncracked concrete, and (b) for cracked concrete with the Simplified Smeared Approach (SSA). The structural integrity of the concrete circular pile is compared before and alter repair, by (a) finite element modeling using ANSYS software with the maximum deflection, and (b) beam strength analysis to find the moment capacity for cracked and ultimate conditions. The overall findings indicate the adequacy of the repair procedures.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13062
- Subject Headings
- Concrete piling, Reinforced concrete--Corrosion, Seawater corrosion
- Format
- Document (PDF)
- Title
- Correlation of Chloride Diffusivity and Electrical Resistance for Cracked Concrete.
- Creator
- Merantus, Stanley W., Reddy, Dronnadula V., Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
The durability of Reinforced Concrete (RC) structures in the Marine environment is causing serious concern in the structural infrastructure. Reinforced concrete structures, exposed to aggressive environments, are expected to last with little or no maintenance for long periods of time. However, one of the most serious environmental exposures that causes degradation is Chloride Diffusion, due to shrinkage, atmospheric corrosion, and tide-induced wet and dry conditions at the air-water...
Show moreThe durability of Reinforced Concrete (RC) structures in the Marine environment is causing serious concern in the structural infrastructure. Reinforced concrete structures, exposed to aggressive environments, are expected to last with little or no maintenance for long periods of time. However, one of the most serious environmental exposures that causes degradation is Chloride Diffusion, due to shrinkage, atmospheric corrosion, and tide-induced wet and dry conditions at the air-water interfaces of coastal structures. Therefore, chloride diffusivity, which correlates with the electrical resistivity, has a significant impact on the durability of concrete. Concrete chloride diffusivity has been experimented by multiple agencies and researchers on sound concrete, but there is a considerable need for investigation of the durability of cracked concrete in the marine environment. The two test methods carried out are presented: Standardized American Society for Testing and Materials (ASTM) C1202 for Rapid Chloride Permeability (RCP) and ASTM D257 for Surface Resistivity (SR), and Nordtest (NT) Build 492 for Rapid Chloride Migration (RCM) and Bulk Resistivity (BR) for both sound (uncracked) and cracked (micro and macro) concrete. The limitations of the ASTM method, due to measurements before the steady-state migration is reached, does not account for leakage in cracked concrete, and the heating of the specimen due to higher current that increase the conductivity are indicated. The Rapid Chloride Migration test provides for the non-steady state of diffusion. Again, Bulk Resistivity, in contradistinction to Surface Resistivity is more accurate for cracked concrete. The correlation betweeen RCM-BR are plotted. Chloride Permeability/Migration is an important parameter that governs the Durability of Concrete. The principal contribution is the highlighting of the inadequacy of the current widely used standard ASTM C1202 for diffusivity testing, and the need for revision with further investigation.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004942, http://purl.flvc.org/fau/fd/FA00004942
- Subject Headings
- Reinforced concrete--Construction--Corrosion., Reinforced concrete--Deterioration., Concrete--Corrosion., Concrete--Chemical resistance., Chlorides--Environmental aspects., Chlorides--Diffusion rate.
- Format
- Document (PDF)
- Title
- Effect of elevated temperature and fire on structural elements retrofitted by carbon fiber reinforced polymer composites.
- Creator
- Young, Jody David, Jr., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
This thesis presents an experimental investigation for evaluating effects of fire exposure on properties of structural elements retrofitted by carbon fiber reinforced polymers. Mechanical properties of CFRP-strengthened reinforced concrete members, protected with secondary insulation, were investigated, before and after (residual) direct fire exposure. Direct fire contact resulted in a reduction in capacity of 9-20% for CFRP-strengthened RC beams, and 15-34% for CFRP-strengthened RC columns....
Show moreThis thesis presents an experimental investigation for evaluating effects of fire exposure on properties of structural elements retrofitted by carbon fiber reinforced polymers. Mechanical properties of CFRP-strengthened reinforced concrete members, protected with secondary insulation, were investigated, before and after (residual) direct fire exposure. Direct fire contact resulted in a reduction in capacity of 9-20% for CFRP-strengthened RC beams, and 15-34% for CFRP-strengthened RC columns. Furthermore, a dimensional analysis was developed for a heat transfer relationship between full and small-scale specimens, allowing a ¼ exposure time reduction for the latter. Results from experimental investigations demonstrate benefits of employing secondary fire protection to CFRP-strengthened structures, in spite of the glass transition temperature being exceeded in the early stages of the elevated-temperature exposure. Therefore, it is suggested, that fire protection is necessary for a CFRP-strengthened structural member to retain integrity throughout the duration of the fire exposure, and upon return to ambient temperature.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13322
- Subject Headings
- Buildings--Repair and reconstruction, Reinforced concrete, Fiber reinforced plastics, Fire resistant materials, Thermodynamics, Heat engineering, Concrete--Effect of temperature on
- Format
- Document (PDF)
- Title
- Fire resistance of corroded structural concrete.
- Creator
- Martinez, Fernando Jose, Reddy, Dronnadula V., Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
One of the major causes of structural repairs worldwide is the corrosion of reinforced concrete structures, such as residential buildings and piers, which are exposed to harsh marine environments. This investigation aims to provide experimental evidence of the fire resistance of corroded high strength reinforced concrete. For this, 14 reinforced concrete beams of three different concrete mix designs (different strengths) were prepared along with concrete cylinders for compression strength...
Show moreOne of the major causes of structural repairs worldwide is the corrosion of reinforced concrete structures, such as residential buildings and piers, which are exposed to harsh marine environments. This investigation aims to provide experimental evidence of the fire resistance of corroded high strength reinforced concrete. For this, 14 reinforced concrete beams of three different concrete mix designs (different strengths) were prepared along with concrete cylinders for compression strength testing (ASTM C39). After proper moist curing, all beams were corroded, in two phases, with impressed current, then “crack scored ”for corrosion evaluation, after which half were exposed to fire, also in two phases, following the ASTM E-119-12 time-temperature curve, using a gas kiln. The fire damage was evaluated and compared between phases by using Ultrasonic Pulse Velocity technology. Finally, all specimens were tested for flexural strength by using the third-point loading method (ASTM C78) and the effects of fire on the corroded beams were analyzed according to the level of corrosion.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004304, http://purl.flvc.org/fau/fd/FA00004304
- Subject Headings
- Concrete -- Effect of temperature on, Fire resistant materials, Reinforced concrete -- Corrosion, Thermodynamics
- Format
- Document (PDF)
- Title
- Rain-wind-induced cable vibrations in cable-stayed bridges.
- Creator
- Calle, Oscar F., Reddy, Dronnadula V., Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
This research is aimed at investigating and analyzing the rain-windinduced cable vibration phenomena experienced in cables of cable-stayed bridges and also the countermeasures employed by engineers to mitigate the large-amplitude vibration problem reported by various researchers around the world. In order to investigate the problem of the water rivulet creation at the top of the cable surface, a single-degree-of-freedom (SDOF) analytical model was developed and analyzed. This thesis studies...
Show moreThis research is aimed at investigating and analyzing the rain-windinduced cable vibration phenomena experienced in cables of cable-stayed bridges and also the countermeasures employed by engineers to mitigate the large-amplitude vibration problem reported by various researchers around the world. In order to investigate the problem of the water rivulet creation at the top of the cable surface, a single-degree-of-freedom (SDOF) analytical model was developed and analyzed. This thesis studies the aerodynamic instability of cables in cable-stayed bridges by doing literature review of a typical in-situ test, developing a single degree-of-freedom (SDOF) analytical model, and an ANSYS finite element model. Furthermore, a linear viscous damper that acts as a countermeasure to the large amplitudes of vibration is reported and analyzed. The suppression characteristics and damper effectiveness of such countermeasure are summarized.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004271, http://purl.flvc.org/fau/fd/FA00004271
- Subject Headings
- Bridges -- Aerodynamics, Bridges -- Vibration -- Prevention, Cable stayed bridges -- Maintenance and repair, Damping (Mechanics), Structural dynamics, Vibration -- Mathematical models, Wind resistant design
- Format
- Document (PDF)