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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 18 Abstracts search results
Document:
SP143-01
Date:
May 1, 1994
Author(s):
M. H. Maher, B. Chen, J. D. Prohaska, E. G. Nawy, and E. Snitzer
Publication:
Symposium Papers
Volume:
143
Abstract:
A novel fiber optic sensor was tested on reinforced concrete beams with the objective of monitoring strain due to flexural deformations. A fiber optic Bragg grating (FOBG) sensor, developed recently at the United Technologies Research Center (UTRC) for monitoring of strain in structural composites, was used. The FOBG sensor was tested in beam models to measure load-induced strain. Results showed that the FOBG sensor can be accurately and effectively used to monitor strain for both existing and new concrete structures. A number of issues, such as sensor bonding to the structural component, sensor placement, and practical instrumentation techniques, were addressed in this study.
DOI:
10.14359/4579
SP143-02
V. Sharma, W. L. Gamble, J. Choros, and A. J. Reinschmidt
Load tests were conducted on three recently constructed precast pretensioned concrete railroad bridges. The three bridges tested were instrumented at their centerline of span with concrete strain gages applied to appropriate locations to quantify the bridge behavior and to obtain impact factors. A dedicated test train was used to apply the loading for all the measurements. This train consisted of two locomotives followed by 10 freight cars representative of most common types of cars used in modern freight trains. The test trains had a total gross weight of 1250 tons and a length of 1400 ft and included five platform-type intermodal cars, 89-ft flat cars (TOFC/COFC), and also hopper and box cars. The test train was operated at speeds of up to 70 mph. Paper describes the bridges tested, with special emphasis on field testing techniques and the personal computer-based data acquisition system.
10.14359/4580
SP143-03
R.L. Nigbor
This review paper discusses current and near-future technologies for measurement of full-scale structural performance. Modern instrumentation and measurement methodologies can provide signals and data for use in evaluating the performance of civil structures. Applications exist in model verification, extreme event monitoring, health monitoring, and serviceability monitoring. Examples are provided, and future developments are discussed.
10.14359/10046
SP143-06
M. Sugita, H. Yanagida, and N. Muto
Carbon fiber glass fiber reinforced plastic (CFGFRP) is used in concrete structures as a reinforcement material. Appropriate materials design indicates that CFGFRP should be a hybrid of a conductive material with a small ultimate elongation value and an insulating material with a large ultimate elongation value. In the present study, the authors evaluated three types of carbon fiber tows used in CFGFRP composites. They observed a very clear and significant change in electrical resistance at the transition point where carbon fiber tows fractured, and found that this point could be easily controlled though the use of carbon fibers with different ultimate elongation values. The electrical resistance characteristics of CFGFRP-reinforced concrete change along with changing loads. Furthermore, a permanent residual electrical resistance could be observed after the removal of load, and its change was dependent on the maximum load applied. The information on the fracture position was obtained by the arrangement of the CFGFRP composites. Monitoring changes in electrical resistance during and after loading is thus a promising method for anticipating the fracture of CFGFRP-reinforced concrete.
10.14359/4317
SP143-12
S. Popovics, R. Silva-Rodrigez, J. S. Popovics, and V. Martucci
Describes a laboratory investigation of an ultrasonic method that has the potential to become, through further research, a valuable tool for the nondestructive quality control of concrete during construction. The primary objective of the work is to characterize the development of internal structure of the portland cement paste portion of concrete from very early ages on by making use of the behavior of propagated ultrasonic pulses. To do that, however, a suitable ultrasonic method first had to be developed, since quite a few publications reported difficulties with such measurements in fresh pastes due to high attenuation. Velocity and attenuation of longitudinal ultrasonic pulses were measured at regular intervals in fresh concretes. The first measurements were usually performed 10 min after mixing and continued up to the age of 28 days. Three concretes of different compositions were tested. This paper concentrates on measurements at very early ages. The instrumentation, test setup, and testing procedure are described. The velocity and attenuation results, as well as their interpretation, are then presented. For instance, it is shown that the time of initial set is close to a minimum on the pulse velocity-versus-age relationship, as well as a maximum on the attenuation-versus-age relationship.
10.14359/4318
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