Journal of Performance of Constructed Facilities

This paper presents research on quality control in seismic-resistant construction. The research objective was to verify compliance with seismic safety features in light residential and commercial wood construction. While the study was on quality control in seismic-resistant construction, the results apply to wind conditions and design flaws as well. The study included two methods: (1) mail surveys of architects and engineers; and (2) site surveys of projects under construction. Results are presented in graphs for visual comparison. Both surveys revealed that more than one-third of seismic safety items were missing or flawed in over 40 of surveyed units (apartments, etc.). It is alarming that the key items to resist wind and seismic loads are among those most frequently missing or flawed, including shear wall hold-downs, nailing, and proportion (aspect ratio); wall-to-wall straps and tie-downs, diaphragm blocking and nailing, drag strut splice, and roof-to-wall anchors. Conclusions include recommendations to improve quality control.

A case study of Northridge Earthquake induced movement of landslide debris is presented. Based on the width of the observed cracks, the estimated earthquake-induced lateral movement of the landslide debris was 6–12 mm (0.25–0.5 in.). Associated with the lateral movement of the landslide debris, there was a differential movement of 102 mm (4.0 in.) of the house foundation and 69 mm (2.7 in.) for the pool. There was severe damage to the house and the appurtenant structures due to the landslide debris movement. Inclinometer readings indicate that the landslide debris continued to move after the earthquake. Because the house was built in 1956, there probably was no geologic investigation which would have detected the unstable geologic condition at the site.

The failure of the Tapo Canyon tailings dam was one of the most striking failures of an earth structure to result from the January 17, 1994 Northridge, California earthquake. The failure involved a 60-m-wide breach of a tailings dam with a maximum height of 24 m, and 60 and 90 m downstream displacements of two sections of the dam. The failure resulted from liquefaction of the impounded tailings and possibly of the embankment materials. A significant volume of liquefied tailings passed through the breach in flows which extended hundreds of meters downstream within a natural drainage channel. The tailings dam failure, which occurred in a largely undeveloped area, caused no deaths or injuries, but did result in considerable economic losses for the owners of the tailings dam and a downstream water-treatment facility affected by the tailings flow slide. In this paper the writers will outline the construction history and geologic conditions at the site, and describe the strong influence of these factors on the characteristics of the embankment failure.

The incidence of professional liability claims against engineers and architects serving the construction industry remains a serious problem. This paper reports the results of an analysis of 370 claims levied against engineers and architects who are insured by Architects and Engineers Insurance Company (AEIC), a risk-retention company providing professional liability insurance to design professionals in the construction field. In presenting this paper, the writers hope that managers of architectural and engineering firms will gain insights valuable for the reduction of errors and omission claims. The frequency of claims and their significant indications (personal injury, design error, etc.) are treated, as are the relationships between design disciplines, project type, work product involved, owner category and others. Although the results reported in this paper are derived from a relatively small database, we believe they are indicative of experiences many design professionals may encounter. As time passes, it is inevitable that additional claims will be experienced and the database will grow to enable refinement of the relationships discussed here.

The objectives of this paper are to identify and assess the relationship between building owners and designers in terms of their interface problems. The methodology utilized in this research consists of two phases. In the first phase, a literature review was conducted, and interviews with various building owners and designers took place in order to identify the interface problems between them. This resulted in the identification of 20 interfaced problems, which were classified into three categories, namely: inadequate contract and specifications, financial problems, and lack of proper communication. In the second phase, a survey of a randomly selected sample of 30 building owners and 30 designers from Saudi Arabia was undertaken to evaluate the severity of the 20 identified interface problems. The relative severity of the problems were determined and then ranked according to a severity index for both owners and designers. The owners evaluated four problems as “most severe,” 14 problems as “severe,” and two problems as “somewhat severe.” The designers evaluated three problems as “most severe,” 15 problems as “severe,” and two problems as “somewhat severe.” It was also found that owners and designers generally agreed on the severity of their interface problems.

A parametric analysis is carried out to study the strengthening requirements of old, timber Warren-truss hangars that the Department of National Defence (DND) of Canada owns and operates. These two-span Warren-truss buildings were constructed in the 1940s and were originally designed as two independent single-span trusses. Load-reversal behavior of a two-span truss system is investigated. Truss members that are overstressed under actual and realistic loading conditions are determined. The general objective of the present study is to ensure that existing timber Warren-truss buildings meet the latest Building Code requirements as well as DND guidelines. Results reveal that more members than that required by the guidelines need to be reinforced to provide proper resistance against specified loads, as outlined in the guidelines and current Building Code.