Journal of Performance of Constructed Facilities

Part of the roof of the newly completed supermarket at the Station Square development in Burnaby, British Columbia, Canada, collapsed during the opening day. Framing was steel bar joists and Gerber system beams, and the roof was used as a parking deck. The government of British Columbia established a commissioner inquiry to ascertain the causes and to make recommendations that could prevent similar occurrences. The principal causes of collapse were an undersized beam and inadequate buckling resistance of both the compression flange of the cantilevered beam and the beam column assembly. The procedures that led to the design error are examined in detail. The inquiry made recommendations designed to strengthen the qualifications of engineers offering consulting services to the public, to clarify the lines of responsibility in the construction industry, and to tighten the practices used in design. Technical recommendations are also made with respect to the design of roof systems of the type involved, which were promptly acted upon by the Canadian Institute of Steel Construction.

National Bridge Inventory (NBI) data for bridges built from 1950 to 1987 were used to identify the 12 most common bridge types. Three of these types account for almost half of the bridges built in the United States during that period but have the highest percentages of structural deficiency as classified by Federal Highway Administration (FHWA) criteria. Many timber stringer and steel stringer bridges built during the 1980s already are classified as structurally deficient in the 1987 NBI. The most common deficiency on interstate bridges is the deck, whereas the most common deficiency on county bridges is the substructure. On the average, in a given state, the three most common bridge types account for two‐thirds of all bridges built within that state during the period 1950–1987. Data for six selected states show considerable variety in types of bridges built, percentages classified structurally deficient, and the most common deficiencies. Data for two adjacent states indicate differences in bridge performance, apparently influenced more by state policies than by climate and load capacity. The study raises questions regarding the effects of local practices on long‐term highway bridge performance.

A number of recently built concrete girder‐slab bridges in Saudi Arabia have been suffering from structural distress to the deck slabs. This distress is mostly characterized by the formation of grid‐patterned cracks to the soffit side of these decks. In several decks, these cracks have progressed and nucleated and eventually led to the formation of localized failures in the form of potholes, thus rendering these bridges out of service. This paper presents a typical case study of a concrete girder‐slab bridge deck suffering from such localized failure. The study shows that although this deck has been adequately designed to meet the loadings imposed by the AASHTO HS‐20–44 + 10% design vehicle, some of the current overweight vehicles can induce high flexural stresses, leading to the formation of severe longitudinal and transverse cracks. Propagation of these cracks into a grid pattern can reduce the punching shear capacity of the deck slab, thus paving the way for a punching shear type of failure. The case study is concluded by a hypothesized mechanism for the formation of potholes in bridge decks.

For much of its early history, the U.S. Army Corps of Engineers concentrated on the design and construction of new facilities, but now the mission of the corps is shifting from construction to the maintenance of existing facilities. The corps has addressed its changing role by instituting a repair, evaluation, maintenance, and rehabilitation (REMR) program. As a part of this program, a research effort that focuses on the evaluation and repair of the steel sheet pile structures within the corps' civilian projects has been undertaken. The objectives of this work are: (1) To develop an inspection and rating system that uniformly and consistently describes the current condition of steel sheet pile structures; and (2) to develop guidelines for the maintenance and repair of these structures. The first objective is described in this paper. The project team at Iowa State University has conducted several site visits and field investigations. Experts from the Corps of Engineers were asked to rate several walls, and the results were compared to a preliminary version of the rating system. Modifications were made to reflect the expert's opinions more accurately. The inspection and rating system given here is now ready for wider distribution and additional feedback.