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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 1-10 of 10 Abstracts search results
November 1, 2005
Matthew J. Schoettler, Jose I. Restrepo, Frieder Seible, and Ed Matsuda
The experimental testing of a bridge pier for seismic performance is presented in this paper. A typical bent of Bay Area Rapid Transit’s (BART’s) West Oakland Aerial Guideway was investigated at half scale. Two pseudo-cyclic bidirectional tests were conducted on a single test specimen modeling an existing pier including proposed retrofit measures. Twenty-four battered piles provided the foundation moment capacity during a system test. This test evaluated the likely failure mechanism of the pile-pile cap connection. The second test isolated the column-footing joint by restraining pile cap rotation and translation. In this test, retrofitted pile cap was evaluated for its joint shear response. The system test results indicated a limited system ductility after pile failure, followed by a rocking response of the pier. Results from the joint shear test indicated the retrofit was sufficient to prevent a joint shear failure and helped establish the allowable column-footing joint shear stress to use in retrofit design.
November 1, 1997
Thomas T. C. Hsu
New torsion design provisions have been proposed for the 1995 ACI Build-ing Code. As compared to the I989 provisions, these generalized I995 pro-visions have three advantages: First, they are applicable to closed cross sections of arbitrary shapes. Second, they are applicable to prestressed concrete. Third, they are considerably simplified by deleting the torsional concrete contribution and its interaction with shear: These new provisions are suitable for application to concrete guideways and bridges, because these large structures are always prestressed and are often chosen to have hollow box sections of various shapes. This paper discusses the back-ground of the new code provisions, suggests modifications to code formulas, and illustrates the application of the code provisions to prestressed hollow girders by way of a guideway example.
September 1, 1986
ACI Committee 358
These recommendations for analysis and design of transit guideways, reported by Committee 3.58, form a procedure for the design of reinforced and prestressed concrete guideway structures for public transit use. The document is specifically prepared to provide design guidance for transit structures. For items not covered here, the reader is referred to appropriate bridge and railroad design codes.
September 1, 1983
Andrzej S. Nowak and Hid N. Grouni
Genrally, transit guideways have been designed using highway and railway bridge design codes. However, there are significant differences berween structures supporting highwuy and roadway traffic and those supporting transit vehicles, particularly, in values and variations of load components. This may result in uneconomical solutions for transit structures. The procedure used to develop criteria for the design of transit guideways is described. Five transit systems were selected. Load components and their variations were determined. Then, load and resistance factors were calculated. The acceptance criterion was closeness of the calculated liability indices to the target safety level. Safety is measured in terms of a reliability index, and design criteria were developed for the ultimate and serviceability limit states.
Ching- Sheng Hwang and Thomas T.C. Hsu
Prestressed concrete double-T-girders, 80 ft (24.4 m) long, 12 ft (3.66 m) wide, 5 ft (1.52 m) deep, and 93 tons (85.3 metric tons), were adapted for the 21 mile (33.8 km) aerial guideway of the Dade County Rapid Transit System. These girders are subjected to large torsional moments caused by wind loads and the nosing/lurching action of vehicles. For the torsional design of these girders, a general method of mixed torsional analysis of channel-type, thin-wall open reinforced concrete sections was developed. This method was based on a mathematical approach using a Fourier Series. In a thin-wail open section subjected to torsion, warping torsional resistance must be considered in addition to the well-known St. Venant torsional resistance. The elastic mixed torsional analysis developed by V. Z. Vlasov is applicable only to reinforced concrete thin-walled sections before cracking. The Fourier Series method proposed is applicable to both the pre-cracking and the post-cracking analysis of such beams. o understand post-cracking mixed torsional behavior, both the post-cracking St. Venant torsional rigidity and the post-cracking warping torsional rigidity must be evaluated. Methods to evaluate post-cracking St. Venant torsional rigidity have been developed in recent years; however, methods to evaluate post-cracking warping torsional rigidity are still unavailable. A bi-material model to determine the post-cracking warping torsional rigidity is proposed.
April 1, 1978
R. A. Dorton and H. N. Grouni
With the recent revival of interest in mass transit systems it has become apparent that a design code covering concrete guideway structures is needed. This paper is considered a necessary first step in preparing a new transit code. Basic design philosophies and criteria adopted by some of the light rail and heavy rail transit authorities in North America are reviewed and compared. The more familiar highway and railway transportation authorities are included for direct comparison. Relevant design criteria of the British Standards Institute are also included as a reference to European systems. The study points out the existence of a wide variation in design concepts and approaches. It also shows that, while certain criteria of guideway design are well covered, other significant aspects are either left out or lack adequate coverage. Recommendations are presented to cover these discrepancies in future codes.
The results of an experimental investigation to determine the time-dependent properties of materials for large prestressed guideway girders are reported. Both elastic and long-term creep and shrinkage deformations were measured on standard 6 x 12-in. cylinders and on full-size reinforced concrete beam sections. Comparisions of the results were used to determine the effect of size on creep and shrinkage. Extrapolatation of the data to other sizes of guideway girders is presented. The results of this study, obtained over a period of two years, can be used in the calculation of camber and axial shortening in girders.
Thomas T.C. Hsu, Mehmet Inan, Leonard Fonticiella
Seven reinforced concrete horizontally curved beams have been tested. Each beam had a cross section of 6 x 12 in. (15.24 x 30.48 cm), a radius of 9 ft (2.74m), and a subtending angle of 90 deg. Each beam was designed to be fixed at both ends and subjected to a concentrated load at midspan. These tests showed that significant redistribution of torsional and bending moments was observed after cracking. Therefore, the conventional design based on "Building Code Requirements for Reinforced Concrete (ACI 318-71)" and the elastic analysis assuming an uncracked section may cause premature yielding or failure at the supports. It is suggested that elastic analysis of moments should be based on cracked sections. The post-cracking torsional sttiffness of curved beams can be reasonably predicted by a theoretical equation derived by the first author.
March 1, 1978
Robert D. Stevens
The Metro Toronto Zoo Domain Ride is a rubber-tired, electrically powered people moveer operating on a concrete guideway. The design and build of this guideway is discussed with emphasis on the specifications and the resulting guideway.
M.W. LaNier and C.W. Dolan
Guideways are integrated structural systems to support and guide modern transit vechicles. A comparision is made between guideways and conventional highway bridges. A evaluation of design objectives and procedures shows that elevated beamways of precast prestressed concrete and continous at-grade pavements provide excellent guideway structures. Some special design considerations are mentioned, and some examples of completed guideways are given.
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