International Concrete Abstracts Portal

This Symposiuml Publication includes 48 papers from the ACI Fifth International Confrence on Innovation in Design with Emphasis on Seismic, Wind, and Environmental Loading, Quality Control, and Innovation in Materials/ Hot-Weather Concreting, held in December 2002 in Cancun, Mexico. Topics include the behavior of flared-column bents under seismic loading, marine exposure of high-strength light-weight concrete, and seismic strengthening of a nonductile concrete frame building. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP209

Completion of the Central A r t e r y b e l Project inchdes development of more that 20 distinct parcels along the original, elevated artery corridor. This paper presents challenges encountered during the design of Parcel 6, which is located between New Chardon and Sudbury Streets in Boston, Massachusetts. The Parcel 6 lid will cover five adjacent cast-in-place concrete boat section ramps. The final use of the lid is not yet known; however, since construction of the ramps is currently underway, the walls were re-designed to accommodate either a landscaped deck, or a five-story building. Design included both wind and seismic lateral analyses of the two types of potential lid structures, with the reinforcing in the ramp walls modified to accommodate both options in order to minimize impacts or retrofits requkd in the future. Changes to the original design included modifying wall heights and reinforcing, and inclusion of interim backwalls for temporary earth support. The landscaped option included preliminary designs of four separate deck structures, skewed portal beams, overhead impact attenuators, and a merge gore area. The building option presumed asymmetrical column loadings and locations, with a comparative analysis of column base shears used to determine maximum loading on the existing ramp walls.

Past Earthquakes have shown that flared columns are susceptible to pre- mature shear failures. In the 1999 Northridge Earthquake, Shear failures have been caused by a plastic hinge formation occurred at the base of the flare and a subsequent increase in the level of column shear demand above design levels. This paper presents an experimental and analytical study that is examining new details for flared columns and joints. The primary feature is a gap at the top of the column and the amount of transverse flare reinforcement. Two two-column bents were tested on the shake table to examine dynamic effects as well as column and beam interaction. The test specimens had different amounts of confining reinforcement in the flare. The detail proved an overall ductility that is above the minimum limit recommended by the current specifications. Test also showed that gap started to close at ductility level that is below the recommended limit.

On June 15, 1999, a magnitude Mw = 7.0 earthquake occurred with epicenter located southwest from the city of Tehuacan, Puebla, and on September 30, 1999, a Mw = 7.5 magnitude earthquake occurred with epicenter located northeast from the city of Puerto Escondido, Oaxaca, Mexico. The earthquakes affected a wide geographical area, including seven states. Few casualties were recorded. In Puebla, 15 percent in the State of Oaxaca and only the remaining ten percent in the States of Morelos, Mexico, Tlaxcala, Veracruz and Guerrero; the second earthquake only affected the State of Oaxaca. Historical buildings, dwellings, hospitals, schools and roads were mostly impacted. Some damages were also experienced in bridges and lifelines. The economic activities were not severely impaired. This paper summarizes the seismological characteristics of the event, its economic impact and the Emergency measures adopted by the authorities. Observation made during several visits to the affected regions of Puebla and Oaxaca on the behavior of soils and foundations, lifeline, schools, dwellings, historical monuments and commercial buildings are described. Recommendations for the development o fvulnerability reduction programs are presented.

An experimental investigation was conducted at the University of Auckland to quantify the performance of shear studs embedded in composite ribbed slabs, formed by casting lightweight polystyrene concrete onto profiled steel decking. In total, 18 tests were conducted using a new type of push-off test rig, with test units composed of either lightweight polystyrene concrete or normal weight con- crete (to facilitate performance comparison). This paper reports and discusses the main results of those 18 tests. Results indicated that in most cases designs utilizing lightweight polystyrene concrete had considerable ductility and shear capacity. Recommended design provisions based on the experimental data are presented.