International Concrete Abstracts Portal

The seismic performance of high type steel bridge bearings of both the fixed and expansion/rocker type were investigated. Simple seismic retrofit strategies were proposed and investigated experimentally. It was shown that by retrofitting existing high type steel bridge bearings, it is possible to provide sufficient strength and displacement capability to withstand substantial ground shaking. The weak link in the chain of force transmission may thus become the anchor bolts and/or the reinforced concrete pedestal. To understand the influence of the reinforced concrete pedestal and mild steel anchorage on the overall behavior of a high type fixed bearing assembly, a full scale reinforced concrete cap beam with pedestals was constructed. The rest results demonstrate the importance of considering the flexibility and strength of the concrete pedestal-anchor bolt system. As a retrofit method for the damaged reinforced concrete pedestal, a steel jacketing retrofit wrapped around the damaged reinforced concrete pedestal and bearing was investigated. Once retrofitted, it is shown that essentially elastic behavior may be expected in an earthquake.

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.