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Investigation of the Suitability of Prepakt Concrete for Mass and Reinforced Concrete Structures

Description: The purpose of the investigation reported herein was to develop data on the suitability of Prepakt concrete for mass concrete dams and for reinforced concrete construction. Prepakt concrete is made by packing the forms with coarse aggregate and then pumping in a cement base intrusion mixture (grout) to fill the voids.
Date: October 1951
Creator: Waterways Experiment Station (U.S.)
Partner: UNT Libraries Government Documents Department

Expedient Reinforcement of Concrete for Use in Southeast Asia: Report 1: Preliminary Tests of Bamboo

Description: "This report summarizes the preliminary results of a current U. S. Army Engineer Waterways Experiment Station (WES) study of the feasibility of using bamboo as an expedient reinforcement for temporary, reinforced concrete structures. The report contains an extensive review of the literature, a description of the test procedures, results of an investigation of the most important engineering properties of bamboo, descriptions of tests of 26 bamboo-reinforced structural elements (20 simply supported beams with 6-ft (1.83-m) spans, and 6 simply supported two-way slabs of varying length, width, and depth), and conclusions and tentative recommendations for the design of bamboo-reinforced structures" (p. xiii).
Date: 1969
Creator: Cox, F. B. & Geymayer, H. G.
Partner: UNT Libraries Government Documents Department

Short- and Long-Time Deflections of Reinforced Concrete Flat Slabs

Description: Summary: "This report summarizes the results of a field investigation to determine the short- and long-time deflections and concrete strains in an Army barracks flat-plate structure at Fort Hood, Killeen, Texas. Due to the rather great slab thickness of 9 in., corresponding to an L/T ratio of approximately 28, all observed deflections were small and in no instance exceeded 0.022 ft, or about 1/800 of the shorter span, during the 45-month observation period, in spite of an early temporary construction load estimated to have been almost 30 percent in excess of the total design load. The measured short-time deflections under various loading conditions compared reasonably well with deflections predicted by use of the ersatz frame analysis method" (p. ix).
Date: February 1970
Creator: Geymayer, H. G. & McDonald, J. E.
Partner: UNT Libraries Government Documents Department

Epoxy injection repairs to concrete in 225-B Building

Description: In 1982, the damaged anchor areas (67 total) in the Operating Gallery and cold manipulator shop ceiling reinforced concrete slabs were epoxy injection repaired by Construction Technology Laboratories (CTL), Portland Cement Association. The through depth vertical cracks (10 total) in the ceiling slabs in the galleries and manipulator shops were sealed and structurally repaired using epoxy injection procedures. The details of the epoxy reRair are reported. Sonic nondestructive (NDT) testing before and after the epoxy injection repairs were made by CTL to confirm that the repairs are structurally effective. CTL recommended to expedite the installation of lateral bracing for the manipulator monorail in order to avoid re-darnage to the repaired anchor areas.
Date: September 19, 1996
Creator: Vollert, F.R.
Partner: UNT Libraries Government Documents Department

The Study of Comprehensive Reinforcement Mechanism of Hexagonal Boron Nitride on Concrete

Description: The addition of hexagonal boron nitride (h-BN) has introduced a comprehensive reinforcing effect to the mechanical and electrochemical properties of commercial concrete, including fiber reinforced concrete (FRC) and steel fiber reinforced concrete (SFRC). Although this has been proven effective and applicable, further investigation and study is still required to optimize the strengthen result which will involve the exfoliation of h-BN into single-layered nano sheet, improving the degree of dispersion and dispersion uniformity of h-BN into concrete matrix. There is currently no direct method to test the degree of dispersion of non-conductive particles, including h-BN, in concrete matrix, therefore it is necessary to obtain an analogous quantification method like SEM, etc. The reinforcing mechanism on concrete, including FRC and SFRC is now attracting a great number of interest thanks to the huge potential of application and vast demand across the world. This study briefly describes the reinforcing mechanism brought by h-BN. In this study, different samples under varied conditions were prepared according to the addition of h-BN and dispersant to build a parallel comparison. Characterization is mainly focused on their mechanical properties, corrosive performance and SEM analysis of the cross-section of post-failure samples.
Date: August 2015
Creator: He, Qinyue
Partner: UNT Libraries

Electrodepostion of Iron Oxide on Steel Fiber for Improved Pullout Strength in Concrete

Description: Fiber-reinforced concrete (FRC) is nowadays extensively used in civil engineering throughout the world due to the composites of FRC can improve the toughness, flexural strength, tensile strength, and impact strength as well as the failure mode of the concrete. It is an easy crazed material compared to others materials in civil engineering. Concrete, like glass, is brittle, and hence has a low tensile strength and shear capacity. At present, there are different materials that have been employed to reinforce concrete. In our experiment, nanostructures iron oxide was prepared by electrodepostion in an electrolyte containing 0.2 mol/L sodium acetate (CH3COONa), 0.01 mol/L sodium sulfate (Na2SO4) and 0.01 mol/L ammonium ferrous sulfate (NH4)2Fe(SO4)2.6H2O under magnetic stirring. The resulted showed that pristine Fe2O3 particles, Fe2O3 nanorods and nanosheets were synthesized under current intensity of 1, 3, 5 mA, respectively. And the pull-out tests were performed by Autograph AGS-X Series. It is discovering that the load force potential of nanostructure fibers is almost 2 times as strong as the control sample.
Date: August 2014
Creator: Liu, Chuangwei
Partner: UNT Libraries

Response of Deep Two-Way-Reinforced and Unreinforced Concrete Slabs to Static and Dynamic Loading, Report 3: Static Tests of Deep Slabs Having a Span-to-Thickness Ratio of 4.12

Description: Partial abstract: "The objective of the investigation reported herein was to obtain laboratory response data for deep, two-way-reinforced and plain concrete slabs subjected to static overpressures in order to determine the response analysis necessary to analyze the target vulnerability of such structures under both active and passive defense situations" (p. 4).
Date: November 1969
Creator: Cole, K. M.; Albritton, Gayle E. & Beavers, James E.
Partner: UNT Libraries Government Documents Department

Modeling coupled blast/structure interaction with Zapotec, benchmark calculations for the Conventional Weapon Effects Backfill (CONWEB) tests.

Description: Modeling the response of buried reinforced concrete structures subjected to close-in detonations of conventional high explosives poses a challenge for a number of reasons. Foremost, there is the potential for coupled interaction between the blast and structure. Coupling enters the problem whenever the structure deformation affects the stress state in the neighboring soil, which in turn, affects the loading on the structure. Additional challenges for numerical modeling include handling disparate degrees of material deformation encountered in the structure and surrounding soil, modeling the structure details (e.g., modeling the concrete with embedded reinforcement, jointed connections, etc.), providing adequate mesh resolution, and characterizing the soil response under blast loading. There are numerous numerical approaches for modeling this class of problem (e.g., coupled finite element/smooth particle hydrodynamics, arbitrary Lagrange-Eulerian methods, etc.). The focus of this work will be the use of a coupled Euler-Lagrange (CEL) solution approach. In particular, the development and application of a CEL capability within the Zapotec code is described. Zapotec links two production codes, CTH and Pronto3D. CTH, an Eulerian shock physics code, performs the Eulerian portion of the calculation, while Pronto3D, an explicit finite element code, performs the Lagrangian portion. The two codes are run concurrently with the appropriate portions of a problem solved on their respective computational domains. Zapotec handles the coupling between the two domains. The application of the CEL methodology within Zapotec for modeling coupled blast/structure interaction will be investigated by a series of benchmark calculations. These benchmarks rely on data from the Conventional Weapons Effects Backfill (CONWEB) test series. In these tests, a 15.4-lb pipe-encased C-4 charge was detonated in soil at a 5-foot standoff from a buried test structure. The test structure was composed of a reinforced concrete slab bolted to a reaction structure. Both the slab thickness and soil media were varied ...
Date: September 1, 2004
Creator: Bessette, Gregory Carl
Partner: UNT Libraries Government Documents Department

Site Cleanup Report for Sites PBF-33 and PBF-34

Description: This document summaries the actions taken to remove asbestos-reinforced-concrete (transite) pipe and miscellaneous debris from Power Purst Facility (PBF)-33 and PBF-34 sites. Removal of pipe and debris were performed in November 2006 in accordance with the requirements discussed in notice of soil disturbance NSD-PBF-07-01. Debris at these two sites were classified as industrial waste that could be disposed at the Central Facilities Area (CFA) landfill at the Idaho National Laboratory. Asbestos removal was performed as Class IV asbestos cleanup work. All transite pipe was double bagged and dispositioned in the INL Landfill Complex at CFA. The remaining miscellaneous debris was loaded into dump trucks and taken to the INL Landfill Complex at CFA for final disposition. Cleanup actions are complete for both sites, and no debris or hazardous constituents remain. Therefore, both sites will be classified as No action sites.
Date: January 16, 2007
Creator: Jolley, W. L.
Partner: UNT Libraries Government Documents Department

Intermittent Cathodic Protection for Steel Reinforced Concrete Bridges

Description: Thermal-sprayed zinc anodes are used for impressed current cathodic protection (ICCP) systems on Oregon's reinforced concrete coastal bridges to prevent chloride-induced corrosion damage. Thermal-sprayed zinc performs well as an ICCP anode but the service life of the zinc anode is directly related to the average current density used to operate the systems. After a ICCP system is turned off, the rebar in the concrete remains passive and protected for a period of time. Intermittent operation of CP systems is possible when continuous corrosion rate monitoring is used to identify conditions when the CP system needs to be turned on to reestablish protection conditions for the rebar. This approach applies CP protection only when needed and reflects the fact that external protection may not be needed for a range of environmental conditions. In doing so, intermittent CP would lower the average current necessary to protect rebar, increase the anode service life, and reduce the lifetime costs for protecting reinforced concrete bridges.
Date: January 1, 2002
Creator: Bullard, Sophie J.; Ziomek-Moroz, Margaret; Cramer, Stephen D.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Russell, James H. et al.
Partner: UNT Libraries Government Documents Department

Evaluation of Simplified Methods for Estimating Shear Capacity Using JNES/NUPEC Low-Rise Concrete Shear Wall Cyclic Test Data.

Description: The simplified methods in current codes for determining the shear capacity of reinforced concrete shear walls had mostly been validated using the test results of single-element shear walls. Recently available JNES/NUPEC test data of reinforced concrete shear walls under multi-directional cyclic loadings provided a unique opportunity to investigate the adequacy of the simplified methods for use in situations with strong interaction effects. A total of 11 test specimens with aspect ratios between 0.47 and 0.87 have been used in the assessment. Two simplified methods from the ACI 349-01 standard [1] and one from the ASCE 43-05 standard [2] have been evaluated. This paper also presents the development of an adjustment factor to consider the aspect ratio and the development of two approaches to consider interaction effects for one of the simplified methods. It concludes with the insights on the applicability of the code methods when interaction effects exist.
Date: June 1, 2008
Creator: Nie,J.; Braverman, J.; Hofmayer, C. & Ali, S.
Partner: UNT Libraries Government Documents Department

An Approach for Assessing Structural Uplifting Using Blast Motions.

Description: The simplified methods in current codes for determining the shear capacity of reinforced concrete shear walls had mostly been validated using the test results of single-element shear walls. Recently available JNES/NUPEC test data of reinforced concrete shear walls under multi-directional cyclic loadings provided a unique opportunity to investigate the adequacy of the simplified methods for use in situations with strong interaction effects. A total of 11 test specimens with aspect ratios between 0.47 and 0.87 have been used in the assessment. Two simplified methods from the ACI 349-01 standard [1] and one from the ASCE 43-05 standard [2] have been evaluated. This paper also presents the development of an adjustment factor to consider the aspect ratio and the development of two approaches to consider interaction effects for one of the simplified methods. It concludes with the insights on the applicability of the code methods when interaction effects exist.
Date: June 1, 2008
Creator: Nie,J.; Xu, J.; Hofmayer, C. & Ali, S.
Partner: UNT Libraries Government Documents Department

Concrete nondestructive tests conducted in 225-B building

Description: In 1982, Construction Technology Laboratories (CTL), Portland Cement Association conducted additional sonic concrete nondestructive testing (NDT) in the Service Gallery on the south process (hot) cell walls and adjacent floor slab, including the locations where significant concrete degradation had been found by the 1981 sonic NDT. In the ceiling slabs, the anchor areas For the monorail hangers, and some visible cracks were sonic NDT inspected. CTL concluded that the hot cell walls have no significant reduction of structural capacity due to concrete degradation. Epoxy injection repairs were recommended by CTL for the damaged anchor areas and through depth cracks in the reinforced concrete ceiling slabs. When completed, the epoxy repairs should be inspected and confirmed with follow on sonic NDT. Lateral bracing for the Monorail system is also recommended to relieve the lateral loads on the hangers.
Date: September 19, 1996
Creator: Vollert, F.R.
Partner: UNT Libraries Government Documents Department

Managing Concrete Structures Aging-One Approach

Description: Research providing guidance on management of aging reinforced concrete structures is summarized. Topics covered include a materials property database, an aging assessment methodology to identify critical structures and degradation factors that can potentially impact performance, guidelines and evaluation criteria for use in condition assessments, and a reliability-based methodology for current condition assessments and estimations of future performance. Applicability of nondestructive evaluation and repair-related technologies is addressed.
Date: June 11, 2001
Creator: Naus, D. J.
Partner: UNT Libraries Government Documents Department

Ultimate capacity evaluation of reinforced concrete slabs using yield line analysis

Description: Yield line theory offers a simplified nonlinear analytical method that can determine the ultimate bending capacity of flat reinforced concrete planes subject to distributed and concentrated loads. Alternately, yield line theory, combined with hinge rotation limits can determine the energy absorption capacity of plates subject to impulsive and impact loads. This method is especially useful in evaluating existing structures that cannot be qualified using conservative simplifying analytical assumptions. Typical components analyzed by yield line theory are basements, floor and roof slabs subject to vertical loads along with walls subject to out of plant wall loads. One limitation of yield line theory is that it is difficult to evaluate some mechanisms; this is aggravated by the complex geometry and reinforcing layouts commonly found in practice. A yield line evaluation methodology is proposed to solve computationally tedious yield line mechanisms. This methodology is implemented in a small PC based computer program that allows the engineer to quickly evaluate multiple yield line mechanisms.
Date: December 31, 1995
Creator: Mertz, G.E.
Partner: UNT Libraries Government Documents Department

Equipment design guidelines for remote hot cell operations.

Description: Hot cells provide a unique and challenging environment for designing remotely operated equipment. A typical hot cell is an isolated room used to protect operators from highly contaminated and radioactive equipment. Hot cells usually have thick reinforced concrete walk and leaded glass windows. Operations within the hot cell are accomplished using master-slave manipulators and overhead crane or electro-mechanical manipulator systems. The inability to perform hands-on operation and maintenance in hot cells requires special design considerations. Some of these design considerations include operational interfaces, radiation, accessibility, replaceability/interchangeability, decontamination, atmospheric conditions, functionality, operator fatigue, and ease of use. This paper will discuss guidelines for designing hot cell remotely operated equipment that has been used successfully at Argonne National Laboratory. General topics in this paper will include master-slave manipulator types and limitations, overhead handling systems, viewing limitations, types and sizes of typical fasteners, hot cell compatible materials, mockup testing, guide features for mating parts, modularity, labeling, electrical fasteners, and lifting fixtures.
Date: July 10, 1998
Creator: Wahlquist, D. R.
Partner: UNT Libraries Government Documents Department

Delamination detection in reinforced concrete using thermal inertia

Description: We investigated the feasibility of thermal inertia mapping for bridge deck inspections. Using pulsed thermal imaging, we heat-stimulated surrogate delaminations in reinforced concrete and asphalt-concrete slabs. Using a dual-band infrared camera system, we measured thermal inertia responses of Styrofoam implants under 5 cm of asphalt, 5 cm of concrete, and 10 cm of asphalt and concrete. We compared thermal maps from solar-heated concrete and asphalt-concrete slabs with thermal inertia maps from flash-heated concrete and asphalt-concrete slabs. Thermal inertia mapping is a tool for visualizing and quantifying subsurface defects. Physically, thermal inertia is a measure of the resistance of the bridge deck to temperature change. Experimentally, it is determined from the inverse slope of the surface temperature versus the inverse square root of time. Mathematically, thermal inertia is the square root of the product of thermal conductivity, density, and heat capacity. Thermal inertia mapping distinguishes delaminated decks which have below-average thermal inertias from normal or shaded decks. Key Words: Pulsed Thermal Imaging, Thermal Inertia, Detection Of Concrete Bridgedeck Delaminations
Date: November 30, 1998
Creator: Del Grande, N K & Durbin, P F
Partner: UNT Libraries Government Documents Department

Effects of Rebar Temperature and Water to Cement Ratio on Rebar-Concrete Bond Strength of Concrete Containing Fly Ash

Description: This research presents the results on an experimental investigation to identify the effects of rebar temperature, fly ash and water to cement ratio on concrete porosity in continuously reinforced concrete pavements (CRCP). Samples were cast and analyzed using pullout tests. Water to cement ratio (w/c) and rebar temperature had a significant influence on the rebar-concrete bond strength. The 28-day shear strength measurements showed an increase in rebar-concrete bond strength as the water to cement ratio (w/c) was reduced from 0.50 to 0.40 for both fly ash containing and non fly ash control samples. There was a reduction in the peak pullout load as the rebar surface temperature increased from 77o F to 150o F for the cast samples. A heated rebar experiment was performed simulating a rebar exposed to hot summer days and the rebar cooling curves were plotted for the rebar temperatures of 180o F - 120o F. Fourier transform infrared spectroscopy was performed to show the moisture content of cement samples at the rebar-concrete interface. Mercury intrusion porosimetry test results on one batch of samples were used for pore size distribution analysis. An in-depth analysis of the morphological characteristics of the rebar-concrete interface and the observation of pores using the scanning electron microscope (SEM) was done.
Date: May 2010
Creator: Pati, Ardeep Ranjan
Partner: UNT Libraries

Effects of Various Blowout Panel Configurations on the Structural Response of Los Alamos National Laboratory Building 16-340 to Internal Explosions

Description: Abstract: The risk of accidental detonation is present whenever any type of high explosives processing activity is performed. These activities are typically carried out indoors to protect processing equipment from the weather and to hide possibly secret processes from view. Often, highly strengthened reinforced concrete buildings are employed to house these activities. These buildings may incorporate several design features, including the use of lightweight frangible blowout panels, to help mitigate blast effects. These panels are used to construct walls that are durable enough to withstand the weather, but are of minimal weight to provide overpressure relief by quickly moving outwards and creating a vent area during an accidental explosion. In this study the behavior of blowout panels under various blast loading conditions was examined. External loadings from explosions occurring in nearby rooms were of primary interest. Several reinforcement systems were designed to help blowout panels resist failure from external blast loads while still allowing them to function as vents when subjected to internal explosions. The reinforcements were studied using two analytical techniques, yield-line analysis and modal analysis, and the hydrocode AUTODYN. A blowout panel reinforcement design was created that could prevent panels from being blown inward by external explosions. This design was found to increase the internal loading of the building by 20%, as compared with nonreinforced panels. Nonreinforced panels were found to increase the structural loads by 80% when compared to an open wall at the panel location.
Date: September 2005
Creator: Wilke, Jason P.; Pohs, Keith G. & Plumlee, Deidré A.
Partner: UNT Libraries Government Documents Department

244-CR Vault Interim Stabilization Project Plan

Description: The 244-CR Vault is a two-level, multi-cell structure of reinforced concrete constructed below grade. The lower cell contains four individual compartments, each containing a steel process storage tank and equipped with a concrete sump. The upper cell contains the piping and support equipment, and has two compartments for each of the tanks. The ''pump pit'' is accessed by the removal of concrete cover blocks, while the smaller ''riser pit'' is accessed by steel cover plates. The facility most recently was used as a double-contained receiver tank (DCRT). A DCRT is a type of waste transfer tank that together with its related equipment constitutes a short-term storage area for liquid waste and has a pump pit for waste transfer operations. This vault most recently was used for short-term storage and waste routing for saltwell liquid pumped from the 241-C Tank Farm in the 200 East Area. Waste transfer lines are connected inside the pump pit by a jumper installed between connecting nozzles. An active ventilation system is in operation at the 244-CR vault. Ventilation supply air enters the upper vault section through an inlet header with some leakage through the spaces between the cell cover blocks. The upper and lower vaults are connected by exhauster ports, which allow airflow between the two sections. Normal flow moves air from the upper cell to the lower cell where it is removed and routed into a filter plenum; there the air is treated by a bank of four prefilters and two banks of high-efficiency particulate air (HEPA) filters (each containing four HEPAs). The air is exhausted to the atmosphere through the 296-C-05 Stack. The stack is equipped with a record sampler and continuous air monitor. Two fans (each rated at 4,200 cubic feet per minute) installed downstream of the filtration system provide the motive ...
Date: April 25, 2000
Creator: PARKMAN, D.B.
Partner: UNT Libraries Government Documents Department