Journal of Performance of Constructed Facilities

Sprinkled surface hardeners are incorporated into freshly placed concrete slabs while high-strength overlays are placed on a previously poured new concrete slab or an existing deteriorated slab, providing improved abrasion and impact resistance. Metal filings are combined with cement corrosion inhibitors and water-reducing admixtures. Depending on the intended application, the metallic particles may either be treated with chemicals or directly sieved and graded. Rusting of metallic surface hardeners can occur when the installation of these products or the conditions during installation are not closely controlled. Visual tests, including microscopy and chemical analysis, were employed to investigate some of the potential factors that contribute to the rusting problem. Observations and possible causes contributing to the rusting and debonding problems are identified: (1) a decrease in the alkalinity of the cement paste due to carbonation; (2) exposure of unprotected metallic particles to air during the brushing procedure; and (3) timing of the finishing operations.

The impulse response test is a nondestructive evaluation technique commonly used for quality control of driven concrete piles and drilled shafts where the pile heads are accessible. When evaluating existing foundations, the presence of a pile cap or other structure makes the pile heads inaccessible and introduces uncertainties in the interpretation of impulse response results. A test section was constructed at the National Geotechnical Experimentation Site (NGES) at Northwestern University to examine the applicability of nondestructive testing methods in evaluating deep foundations under inaccessible-head conditions. This paper focuses on the results of impulse response tests conducted atop the three pile caps at the NGES. Based on field experimentation and numerical simulations, a frequency was determined below which the impulse response test could be used for inaccessible-head conditions. This cutoff frequency primarily depends upon the geometry of the pile cap and pile. A case study is presented that describes impulse response tests obtained on a number of drilled shafts both after the shaft was constructed and after grade beams and walls were built. The results of these tests also follow the trends observed in the NGES tests related to cutoff frequency.

Upgrading of elevators is carried out in the interests of maintaining building quality and attaining market rental income. Difficulties experienced in the upgrading of elevator systems indicate a need for development of guidelines to be considered in the initial design of buildings to facilitate upgrading of elevator systems in the future. The focus of this paper is on the development of design guidelines for the potential upgrading of elevator systems in high-rise buildings. A case study as to the difficulties encountered in upgrading an elevator system is included. Some types of upgrading and replacement now possible are reviewed. Responses from 92 design professionals (architects and engineers) in nine countries—namely, the United States, Japan, Canada, Australia, United Kingdom, Singapore, Spain, Saudi Arabia, and Kuwait—to a survey on the upgradeability of elevators have been summarized in the form of guidelines for use by building designers.

The responses to a survey of engineering course contents are summarized. In 1998 a questionnaire was sent to 238 Accreditation Board for Engineering and Technology (ABET) -accredited universities and 62 ABET-accredited civil engineering (CE) technical colleges across the United States. The questionnaire focused on the inclusion of failure awareness of constructed facilities in the CE education curriculum. Of the 300 questionnaires sent, 112 were returned. Survey results reveal that, although a majority of colleges recognize the importance and need of providing failure analysis topics in CE courses, they also feel the undergraduate curriculum to be already crowded. In addition, the respondents say that ABET should not establish an accreditation requirement regarding the subject. However, 37% of the colleges say that three or more lectures should be given on failure analysis, either integrated throughout the course or given in series all at once. And, more than half of the respondents think that condition assessment and maintenance of constructed facilities is a topic that should be included in the CE undergraduate curricula.

Literature on disasters provides the focus for student-based learning exercises in civil and architectural engineering at Queen's University, Belfast, which have been ongoing since 1994. Incorporating these studies in the early part of the curriculum helps students to reorientate from their previous mainly science-based study by gaining some knowledge of the roles, responsibilities, priorities, and work practices of engineers in a way that would not be possible through lectures. In view of the influence of disasters on engineering thinking and work practice, they should have a much larger influence than they currently do on curriculum development.