International Concrete Abstracts Portal

From shortly before the entry of the U. S. in World War II and to the present, the author has been continuously involved in the design, testing, manufacturing, and observation of the performance of joints of all types, from pavements to bridges, and bearings of all types, from the old rockers to elastomeric, pot, disc, and then to earthquake isolation concepts. Starting out with load transfer devices buried in concrete pavement joints for state highways and airfield pavements to field molded sealants and then compression seals, the design trend in pavements has been from longer 100 ft panels (30 m) to relatively short panels of 15 ft (4.5 m). This has greatly simplified the sealing problem, since the distance changes between joint interfaces of shorter length panels obviously are much less in creep-shrink and thermal volume change. With respect to bridges, the design trend has been reversed, going from relatively short decks of 40 ft (12 m) to longer and longer spans, greatly complicating the sealing problem. It was in this confused design period that the writer worked toward developing sealing and bearing systems for every conceivable type pavement or bridge structure. Some lessons learned during the past 50 or more years are the subject of this paper.

Important and often overlooked parts of any building or structure are the systems located behind the walls, under the floors, and in the ceilings of these structures. Installed when the framework of a building is just taking shape, these systems provide the occupants of the building with potable water and remove the waste water safely, quietly, and efficiently. Because these systems are installed within walls, floors, and ceilings, the reliability and longevity of the systems must be equal to the expected life of the building. Two such systems are the sanitary and stormwater piping systems found in all buildings. The wastewater system removes wastewater from the bathrooms, kitchens, and restrooms located inside these structures. The stormwater or rainwater systems drain the exposed roofs, patios, and terraces of rainwater, melted snow, and ice. Both systems use cast iron soil pipe, which is joined with varying types of fittings, within the building's structure. Both systems operate in nonpressure applications, using gravity to remove the rainwater and wastewater from the building. A necessary part of these piping systems is a reliable, cost efficient method of joining the pipe and fittings. This paper traces the history of cast iron soil pipe and discusses design changes in pipe and fittings and the development of applicable standards.

Describes the Washington State Department of Transportation's (WSDOT) experience with fabric pad slide bearings for concrete bridges. Fabric pad design criteria are reviewed. A recent WSDOT project is presented as a case study. Sliding fabric pad bearings are used at the end piers of a four-span concrete segmental bridge. These bearings are designed for a service load of 270 tons with compressive stress of 9.3 MPa. Lateral loads are resisted by transverse concrete girder stops. Load versus rotation discrepancies between AASHTO LRFD, WSDOT, and industry criteria are compared. The current AASHTO LRFD load versus rotation design criteria may be too restrictive for fabric pad bearings. WSDOT's design methodology and costs are presented. Additional research and testing are needed to develop performance-based AASHTO LRFD design specifications. AASHTO material and testing requirements for fabric pad slide bearings are needed so that bridge designers can design and specify these bearings with greater confidence. Fabric pad bearings are capable of supporting high loads. In addition, fabric pad bearings are durable, simple to install, and relatively maintenance-free. The paper concludes that these bearings are an economical alternative to more expensive disc, pot, and spherical bridge bearings.

For a connection of a column and pile made of concrete-filled steel pipes with different diameters, a simple overlap joint in which a smaller diameter pipe is inserted by the specific length to a larger diameter pipe with concrete filled between them has been proposed as an economical and effective joint system. In the present paper, the load- carrying capacities and failure mechanisms of the present joint system are experimentally investigated. The experiments indicate that the ultimate and yield loads increase proportionally with the increase of the overlap length and the wall thickness of pile pipes. In addition, a method to predict ultimate loads of the present joints has been proposed.

The objective of this study was to investigate the seismic performance of laminated elastomeric and lead-rubber seismic isolation bearings under cold climate conditions. To this end, comparative test results are presented of laminated elastomeric and lead-rubber bearings in warm and cold temperature conditions. The effect of strain rate is also investigated. The mechanical properties of elastomers are time dependent. Strain rate has an influence on the behavior of rubber and must be accounted for when modeling the laminated elastomeric and lead-rubber base isolation bearings.