Journal of Performance of Constructed Facilities

Several premature fatigue failures of modular bridge expansion joints have occurred in Europe and the United States. The principal causes of such failures have been poor detailing (for instance, choice of fillet welds instead of full-penetration welds) and the tendency to reduce production costs by adopting larger beam spans. A critical analysis of data from field measurements is discussed. This analysis is focused on (1) the magnitude of the forces acting on the considered component of the joint (center beam), (2) the dynamic amplification factor due to the impulsive axle loading, and (3) the dynamic properties of the joint such as damping, natural frequencies, etc. Comparisons with results obtained by other researchers are presented. A simplified method for the dynamic analysis of the joint is proposed and compared with results obtained from field measurements. Finally, results from laboratory fatigue testing are reported, together with a proposal for a “reasonable” fatigue design load, based on traffic considerations.

A coupled thermal-structural analysis is carried out using both a two- and a three-dimensional finite-element method. The computer program ANSYS is used and simulates the construction process of a roller compacted concrete (RCC) dam. Thermally induced stresses are computed for the 60 m high RCC Tannur Dam in Jordan. The actual temperature distribution in the body of the dam measured by thermocouples is compared with that obtained by ANSYS; generally, a good agreement is obtained. The study demonstrates that detailed thermal stress analysis should be performed for large RCC dams to provide a basis to minimize and control the occurrence of thermal cracking.

This paper describes the condition assessment of a 30 year old cement works, where some of the structures were clearly deteriorated. It was carried out for the purpose of obtaining material properties needed for evaluating strength and integrity, and for establishing durability. This was done by sampling the structures using the nondestructive techniques of visual inspection, perusal of drawings, ultrasonic pulse velocity measurements, covermeter surveys, and core testing. Core testing gave information not only about strength but also about sorptivity, carbonation, chlorides, and sulfates, and about the variation of some of these properties with depth from the concrete surface. Some new approaches were used to estimate the grade of concrete and the partial safety factor for reinforcement. The use of “twin cores” (surface and internal) indicated that the surface quality of the concrete was actually better than the internal quality. Recommendations for repair and maintenance dealt with (1) accumulated cement dust; (2) concrete deterioration; (3) areas experiencing elevated temperatures; and (4) waterproofing of the concrete surface.

The 1995 Hyogo-ken Nanbu (Kobe), Japan earthquake provided the world’s first experience with earthquake damage to new long-span bridges designed to 1990s seismic standards. This paper reviews damage and describes techniques used to repair three major steel bridges along the Wangan route (Bayshore route) in Kobe—the 885 m Higashi-Kobe Bridge, the 217 m Rokko Island Bridge, and the 252 m Nishinomiya Port Bridge. These bridges, in service for less than three years, were essential components in the highway transportation system in the Kobe region. Extremely large ground motions, and failure of bearings, connections, and seismic restrainers were principal contributors to the damage sustained by these bridges. Repairs utilized heavy-lift floating cranes (up to 4,100 ton capacity) and various jacks to stabilize the structures and to realign spans. In one case, reconstruction of a collapsed span was required, with lifting weight a prime concern. Significant constraints on the repair included confined working space and requirements for maintaining maritime navigational clearances. The closure times for the repair of the bridges ranged from three to nine months.

Corrosion rates were measured at the exposed spots of rebars near three corners of Muddy Creek Bridge located in northern West Virginia using a 3LP device. Also, chloride contents of the concrete samples taken from the vicinity of the spots were analyzed using a wet chemical method that had been developed in this study. The average corrosion rate over the three spots was 4.66 mA/m², which is in the range of corrosion damage possible in 10–15 years. The average chloride content of the concrete over the three spots was 703 parts per million (ppm), which is well above the threshold limit value of 260 ppm. Although the corrosion rate measurement method using a 3LP device is by manual operation, it is found to be reliable and effective, and, thus, recommended for future studies of this kind of research. The wet chemical method developed in this study is found to be effective.