Journal of Performance of Constructed Facilities

In September 1982, the flexibility of the University of Illinois Memorial Stadium balcony allowed spectator‐generated vibrations and movements that were disturbing to occupants. Both horizontal and vertical deflections were reported by spectators. An investigation was undertaken to assess the safety of the stadium, to determine the cause of the reported movements, and to make recommendations for any necessary corrective work. Inspections revealed corrosion of structural steel and deterioration of concrete, but these were not significant enough to influence the deflections. Measurements of the vertical and horizontal response verified the flexible nature of the steel structure. The investigation also determined that the character of the live load probably generated the disturbing vibrations and deflections. Balcony girders were strengthened and stiffened. A bracing system was installed to reduce the vibrations felt and observed by spectators. This rehabilitation reduced the natural vertical frequency and the maximum peak‐to‐peak displacement of the structure. In addition, the rehabilitation eliminated spectator reports of discomfort due to the deflections. Throughout this investigation and rehabilitation, it was recognized that the dynamic characteristics of structures must be such that magnitudes of deflection are not disturbing to occupants.

On the morning of October 2, 1982, a fire broke out at an abandoned training facility on an army base in Boston, Massachusetts. While firemen were fighting the fire from the roof, the roof collapsed, shearing the roof trusses away from the columns, and falling straight down leaving all the walls standing. Three firemen were permanently disabled, while others sustained injuries of varying severity. Because of the extra‐ordinary mechanism of collapse, an investigation into the probable causes of collapse was undertaken. The building had been cleaned up immediately after the fire and no physical evidence existed, except for some photographs that were taken by an arson‐squad investigator some hours after the fire. The investigation, which was begun in October of 1987, showed that the building had been moved in the late 1950s. Without any opportunity to investigate the building after the collapse, a case was made that the building had not been constructed properly, either originally or after the move, and that most likely the collapse occurred because some shear rings had been left out. After one day in court, the Federal Government settled.

The Stewart Mountain Dam is a 212 ft (64.6 m) high multicurvature thin‐arch dam. The structure was completed in 1930. It has experienced alkali‐silica reactions within the concrete and exhibited no bond across horizontal construction lift surfaces. The dam could be subjected to upgraded maximum credible earthquake (MCE) or probable maximum flood (PMF) loadings. Alkali‐silica reactions and expansions have caused visible surface cracking. This structure was analyzed for gravity‐, reservoir‐, temperature‐, and earthquake‐induced loads. Results indicated an unsafe structure for earthquake conditions. Several measures for prevention of further deterioration and strengthening were considered. Postten‐sioned cables were selected to provide seismic strengthening. Cable design uses the stiffness, and acceleration response spectra methods. Vertical posttensioned cables are being installed during 1990–92 construction phase. This paper summarizes various field and laboratory investigations, structural analyses, and design parameters needed for posttensioning a deteriorated arch dam. Posttensioned cables are found to be a viable solution for the dynamic stability of a thin‐arch dam. Methodology presented in this paper is applicable to other deteriorated dams.

The nation's bridges are deteriorating at an alarming rate. Bridge management deals with the improvement of these bridges through systematic inspection and maintenance. Inspection of bridges in the United States is normally performed at two‐year intervals, subject to change if requested by state agencies. This paper proposes an inspection strategy based on a bridge‐deterioration model obtained through statistical analysis of bridge‐inspection data in the state of Florida. The methodology for deriving deterioration models is presented in a flowchart. A case study is presented to illustrate the methodology. The inspection strategy is simulated using the derived deterioration model, and results are compared with the current Florida Department of Transportation (FDOT) practice. The proposed inspection strategy schedules bridge inspection based on the prediction of the bridge condition. Implementing the strategy results in economic savings of 38% and the untying of personnel and equipment.

Structures are used for a wide variety of purposes, some being residential, commercial, industrial, environmental, or transportational in nature. The construction process involves a number of procedures that follow together from the first stage of the building process to the end of the life cycle of the structure. The building process of any structure, regardless of its type, location, price, or any other factor, basically includes planning, design, construction, utilization, demolition, and alteration phases. The concepts of structural and construction safety are still issues of concern for engineering practitioners. The relative importance of structural and construction safety is associated with the adverse consequences that may result from a structural and/or construction failure. A recent study of 604 structural and construction failures in the United States during the period 1975–1986 is presented. The analysis aims to demonstrate the practical dimensions and causes of structural and construction safety problems, to evaluate the social and economic consequences of failures, and to assist in providing guidelines to control and improve the safety of facilities during and after construction. In addition, an attempt has been made to estimate safety‐risk measures for the U.S. construction industry.