ACI Global Home Middle East Region Portal Western Europe Region Portal
Email Address is required Invalid Email Address
In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Learn More
Become an ACI Member
Topics In Concrete
Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 61 Abstracts search results
Document:
SP94-33
Date:
July 1, 1987
Author(s):
T. Kelly and I. Buckle
Publication:
Symposium Papers
Volume:
94
Abstract:
Elastomeric bearings have long been used for bridge structures to provide thermal movements and girder rotations under service loads and in building structures to isolate them from ambient vibrations. By increasing the total rubber thickness and by inserting a lead plug for energy dissipation, the function of the bearing may be extended to provide seismic isolation of bridges. Seismic isolation is a design concept that reduces earthquake forces by factors of up to 10, thus greatly enhancing the seismic resistance of the supported structure. This paper provides design guidelines to enable lead-rubber bearings to safely and efficiently act as seismic isolators and reviews the mechanical properties of lead-filled elastomeric bearings. Factors affecting the elastic and postelastic properties are listed, and other design-related parameters are described. A set of design procedures to incorporate the lead-rubber bearings for bridge structures is presented. These procedures include the determination of plan size to support gravity loads, the rubber thickness to provide the required flexibility, and size of the lead core to provide energy dissipation. The procedures are applicable for areas of low and high-seismic risk. The application of the procedures is illustrated by use on a seven-span bridge.
DOI:
10.14359/1679
SP94-34
W. Kauschke and M. Baigent
PTFE is now the most commonly used sliding material used in bridge bearings throughout the world. However, achieving the full advantages of its use over more traditional materials requires careful detailed design. The design and manufacture of PTFE bridge bearings has become a specialty field. Some critical features in the design of PTFE bridge bearings are described. Experimental work on actual structures is described, as well as the calculations made of the life of PTFE surfaces in bearings and their rotational characteristics. Suggestions for further investigations are made.
10.14359/1680
SP94-44
S. Pabst
Elastomeric concrete, when used as a transition medium in the traffic impact area, is a simplistic low-profile concept that vulcanizes permanently to the structural concrete of the bridge deck. This procedure has proven effective in waterproofing the problematic expansion joint areas while providing a unique impact-attenuating transition solution.
10.14359/3419
SP94-46
C. Redfield and C. Seim
What does an engineer do when a defective pot bearing needs replacing? This particular situation was encountered on two recent construction jobs. Several of the pot bearings on the Cline Avenue Project in East Chicago, Ind., needed to be replaced because the elastomer was extruding from the pot. On the I-285 project in Atlanta, Ga., six pot bearings were misaligned and had to be readjusted. The superstructure on both projects was cast in place prestressed concrete box girders. The performance of replacing the pot bearings required designing, fabricating, and installing temporary steel frames, performing special jacking operations, and removing and replacing the pot bearings. This paper describes the operation for both projects in hopes that the solutions illustrated herein may be used by others to help solve similar problems.
10.14359/3425
SP94-49
B. Rogers and D. Shelangoskie
Central to the design of the Intermountain Power Project (IPP) mechanical cooling towers was the ability to configure connections between precast concrete members so that large horizontal seismic forces could be transferred between beams and girders and between girders and columns. Complicating the task of connection design were substantial thermal loads and severe environmental conditions. To solve these and related design questions, a testing program was undertaken using «-scale models of certain key joints in the structure. This paper presents a description of the testing program, a brief description of the structural system in which the joints were located, and the results and conclusions of the tests. Principal among the conclusions is the recognition that embedded metal pins used to transfer forces between discrete members must not only be carefully detailed, but they also must accommodate substantial elastic deformation at the joint if failure below acceptable force levels is to be avoided. In the IPP, this was accomplished by the introduction of a confined viscoelastic medium surrounding the pin. This simple addition to the joint configuration increased the force transferred through the connection by a factor of 2.5 to 3 while limiting deformation to acceptable values.
10.14359/3434
Results Per Page 5 10 15 20 25 50 100
Edit Module Settings to define Page Content Reviewer