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:
SP94-42
Date:
July 1, 1987
Author(s):
M. Bujtas
Publication:
Symposium Papers
Volume:
94
Abstract:
A concept of pot bearing rotation and its relation to vertical load, rotating moment, and eccentricity are examined. At certain low load and rotating combinations, uniform piston contact with the elastomer or the upper element will not occur, resulting in an uneven load transfer and increased eccentricity. Factors that may be traced to this phenomenon are presented. The rotating moment expression used contains an empiric "alpha factor" variable with three known values. Derived from early rotation tests, this "alpha" is based on the diameter-to-height (D/h) ratio of the confined elastomer. An expression for "alpha" was formulated to provide unique factors for each case. Eccentricity and eccentric neutral stress points were computed in all cases. Critical loads are indicated where piston contact loss is possible. This occurs when the eccentricity is less than the eccentric neutral stress point and at the maximum kern of the inner pot section. Piston separation here is likely, due either to the extreme eccentricity or the confined elastomer's resistance to deform at low pressures. Its importance should not be overlooked as future studies may provide substantiation. However, in assuming static equilibrium, complete piston contact is assured so long as the eccentricity remains within the kern of the pot section.
DOI:
10.14359/3413
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
SP94-57
J. Breen
The paper is the text of the keynote address presented at the Second World Congress on Joint Sealing and Bearing Systems for Concrete Structures. The speech centers on Breen's structural engineering experience with reinforced and prestressed concrete and long-span bridges.
10.14359/3777
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