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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 91 Abstracts search results
Document:
SP128-48
Date:
November 1, 1991
Author(s):
R. A. Bates, M. V. Harley, G. G. Payne, and R. A. M. Watkins
Publication:
Symposium Papers
Volume:
128
Abstract:
The Hong Kong Housing Authority maintains an extensive portfolio of property that includes over 700,000 flats. In 1985 it embarked on a major structural investigation of 828 housing blocks, and a US $200 million repair program. The investigation has involved over one million visual inspections, testing of 30,000 concrete cores and an extensive nondestructive testing program. It was necessary to develop methods of appraising low strength concrete structures, and unique strengthening and repair techniques. The paper examines the development and implementation of an investigation and maintenance strategy that takes into consideration the condition, life expectancy, and environment of each building. The paper focuses on the way priorities were determined and research undertaken. It discusses the public relations and management of a program that has required the strengthening of 92 high-rise buildings, and 400,000 mý of spalling repairs over a six year period.
DOI:
10.14359/3458
SP128-50
Ying-Suyuan and Marton Marosszeky
Six single-span beams and two two-span beams with preformed cavities simulating concrete spalling were cast and long-term tests were carried out to investigate the performance of structural repair. The early age properties of three types of polymer-modified concrete, i.e., tensile strength, modulus of elasticity, shrinkage and creep, were investigated under the same environmental conditions as the beams. The test results show that the effect of shrinkage of polymer cement concrete on the stress at serviceability of a repaired structure is quite significant. The restrained shrinkage can lead to cracking in the repair patch and to additional tensile stresses in the substrate. Simulation analyses were also carried out to support this experimental investigation. An analytical method has been calibrated by the test results. Tests and analyses show that the major factors influencing the performance of structural repair include free shrinkage, creep coefficient and tensile strength and ultimate tensile strain in early age properties of a repair material. Stiffness of the member and moment redistribution in the repaired structure are also important.
10.14359/3460
SP128-70
Gordon A. Lang and Anthony G. Martin
A major rehabilitation of the reinforced concrete approach viaduct to the Pattullo Bridge has been successfully completed over the last nine years. A condition inspection revealed that extensive cracking had taken place over the years,especially at the bridge girder ends due mainly to frozen bearings. A program of bearing replacement was carried out at all girder ends along with seismic improvements and general concrete repairs. An elaborate falsework system was designed which was easily adaptable to the varying geometry along the viaduct. Load transfer to the falsework to implement the rehabilitation was achieved using a hydraulic jacking system. The work was carried out in a series of six contracts and the project was completed without any bridge traffic closures during the assignment.
10.14359/3465
SP128-63
Kouichi Satoh, Katsumi Kodama, and Hiroyasu Ohki
Recently, deterioration of reinforced concrete structures has been an issue of concern, such that repair methods and repair practice have been studied by many organizations. In this study the flexural behavior of FRP reinforced concrete beams (FRPC beams) was studied. The experimental values of the tensile stress in the main reinforcement, the concrete crack width, and the center displacement of FRPC beam agreed well with the calculated values. The flexural behavior of repaired reinforced concrete beams (RRC beams) using FRP and polymer mortar was studied. The results showed that tensile stress in the main reinforcement, the concrete crack width, and the center displacement of the beam were decreased after repair work. The elastic theory of reinforced concrete was still effective on the repaired beam. The values of tensile stress in the main reinforcement, and the center displacement of the beam could be calculated.
10.14359/2335
SP128-67
Chil-Lim Park, and Sung Won Yoon
This paper deals with a new type of semiprefabricated slab. The slab is made of precast thin slab stiffened by a set of folded wire fabric including cast in-situ topping concrete. This study covers both the salient features of design and construction of this flooring system and experimental work carried out to study the flexural behavior of the slabs cast using the system. The results of the experiment showed that composite precast slab consisting of the precast thin slab and in-situ topping concrete can be designed as a monolithic component.
10.14359/2344
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