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International Concrete Abstracts Portal

Showing 1-5 of 65 Abstracts search results

Document: 

SP164-30

Date: 

November 1, 1996

Author(s):

Moussa A. Issa, Brenda Robinson, Moshen Shahawy

Publication:

Symposium Papers

Volume:

164

Abstract:

To assist bridge engineers in the State of Florida in selecting expansion joint systems, the Florida Department of Transportation/Structural Research Center (FDOT/SRC) concluded a two year bridge expansion joint evaluation program. This program consists of three components: I) Performance Evaluation, 2) Load Test Evaluation, and 3) Installation & Maintenance Evaluation. The test elements include seals. compression seal joints, strip seal joints, and buried joint systems. Twelve (12) joint suppliers volunteered to participate in the program. A total of seventeen (17) joints (or seals) were installed in eight (8) bridges on I-95 in Saint Lucie County, District IV. All bridges in the test program have prestressed concrete AASHTO girders and concrete deck slabs. All the bridges had armored compression seals at the end bents. In general, the test joint systems or seals were installed at the end bent joints (replacing the original material). The original design joint opening at 70 "F was one inch (1") for the end bent joints. Using criteria recommended by FDOT engineers and the Structures Design Guidelines, the SRC evaluated the test expansion joint sealants or systems. This paper presents the results of the test program. Also, it provides guidance concerning the selection of expansion joint systems for both new and existing bridges.

DOI:

10.14359/14316


Document: 

SP164-13

Date: 

November 1, 1996

Author(s):

T. Ivan Campbell

Publication:

Symposium Papers

Volume:

164

Abstract:

The mechanics of load transfer in the curved sliding compression- only surface of a spherical bearing, containing a layer of polytetrafluoroethylene (PTFE), under external applied horizontal load and the implications for design of such a bearing are the topic of this paper. Relevant literature indicates that the critical parameters are the ratio of horizontal to vertical load and the ratio of the radius of curvature to the plan diameter of the interfacing spherical surfaces. An experimental program to measure the stress-displacement relationship of confined PTFE discs, under uniaxial and eccentric compressive loading, is described and a bilinear stress-displacement relationship is proposed. This stress- displacement relationship is incorporated into a displacement model to predict the stress distribution in the PTFE in the curved interface; this model is used to develop design charts for spherical bearings under combined vertical and horizontal loads.

DOI:

10.14359/1521


Document: 

SP164-17

Date: 

November 1, 1996

Author(s):

J. Valvezan, D. Gilstad, and F. Farhangi

Publication:

Symposium Papers

Volume:

164

Abstract:

After 18 years of service, the pot bearings of the New Carrolton Route Section D-10, part of the Washington, D. C. Metropolitan Area Transit Authority's metro system, are being replaced. Access to the bearings is extremely limited because the bearings are architecturally sealed behind cover plates within box girders. This paper highlights the need to design bridges with access for maintenance, inspection, and bearing replacement. It also discusses issues relating to the long term performance of bearings.

DOI:

10.14359/1551


Document: 

SP164-12

Date: 

November 1, 1996

Author(s):

John A. Van Lund

Publication:

Symposium Papers

Volume:

164

Abstract:

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.

DOI:

10.14359/1389


Document: 

SP164-02

Date: 

November 1, 1996

Author(s):

William H. Le Van

Publication:

Symposium Papers

Volume:

164

Abstract:

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.

DOI:

10.14359/1388


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