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A. G. Brady

Publications and source records attributed to A. G. Brady.

At least 19 recordsLinked to original sources
USGS1989

Recorded seismic response of a base-isolated steel bridge carrying a steel water pipe

A set of strong motion records was obtained from the base-isolated Santa Ana River Pipeline Bridge during the magnitude 5.9 Whittier Narrows, California, earthquake of October 1, 1987. The analysis of the records show that the level of excitation was not strong enough to fully activate the base isolators. The dominant modes of the response are the translations of the abutment-bridge-pipe system in the longitudinal and transverse directions, and the bending of the steel truss between supports in the vertical direction.

Conference Paper↗
USGS1988

The Whittier Narrows, California earthquake of October 1, 1987: Preliminary assessment of strong ground motion records

More than 250 strong-motion accelerograph stations were triggered by the Whittier Narrows, California, earthquake of 1 October 1987. Considering the number of multichannel structural stations in the area of strong shaking, this set of records is one of the more significant in history. Three networks, operated by the U.S. Geological Survey, the California Division of Mines and Geology, and the University of Southern California produced the majority of the records. The excellent performance of the instruments in these and the smaller arrays is attributable to the quality of the maintenance programs and their funding and personnel requirements. Readiness for a magnitude 8 event is directly related to these maintenance programs. Prior to computer analysis of the analog film records, a number of important structural resonant modes can be identified, and frequencies and simple mode shapes have been scaled. The structural records form a basic performance measurement for comparison with larger earthquake response in the future.

California↗
USGS1986

REVERSING CYCLIC ELASTO-PLASTIC DEMANDS ON STRUCTURES DURING STRONG MOTION EARTHQUAKE EXCITATION.

Using the horizontal components from El Centro 1940, Taft 1952, and 4 accelerograms from the San Fernando earthquake of 2/9/71, the time history of the elasto-plastic displacement response was calculated for oscillators having periods within the range of 1 to 6 s and ductility factors within the range of 3 to 6. The Nth largest peak of the elasto-plastic response (N equals 2,4,8,16), when expressed as a percentage of maximum response (that is, N equals 1), is fairly independent of period within our period range. When considering only plastic peaks occurring, sometimes in a one-directional group of peaks, in the reverse direction from the preceding plastic peak, the amplitude of the Nth reversing plastic peak is similar to the Nth elastic peak, regardless of the ductility factor.

Conference Paper↗
USGS1986

FUNDAMENTAL MODAL BEHAVIOR OF AN EARTHQUAKE-EXCITED BRIDGE.

The magnitude 6. 1 Morgan Hill, California, earthquake of April 24, 1984, produced a set of acceleration records at the freeway overpass in San Jose carrying I-280/I-680 across U. S. 101, 12 km from the epicenter. Peak accelerations reached 0. 10 g at ground level and 0. 16 g in the box girder. The integrated displacements at frequencies higher than 3 Hz permit the identification of the fundamental modes and frequencies. The horizontal modes have frequencies of 308 and 3. 9 Hz and include ground level motions up to 90% of peak deck motion. The soil-structure system contributes to these modes.

Conference Paper↗