International Concrete Abstracts Portal

Showing 1-5 of 359 Abstracts search results

Document: 

SP364_7

Date: 

December 1, 2024

Author(s):

Christopher J. Motter

Publication:

Symposium Papers

Volume:

364

Abstract:

Retrofit of reinforced concrete bridge columns with steel jackets is a commonly implemented strategy to increase column ductility in earthquakes. If the steel jacket retrofit is designed using available guidelines, fatigue fracture of longitudinal reinforcement is a likely cause of strength degradation. Fatigue fracture in reinforcement is dependent upon strain history in reinforcement. A model was developed to determine the strain history in longitudinal reinforcement at the plastic hinge in steel jacket retrofitted reinforced concrete columns. The model was validated with existing test data, and single degree of freedom nonlinear time history analyses were conducted using the model. Earthquake duration was shown to have a significant impact on the number of plastic excursions and the total plastic strain in the reinforcement, based on the results of analyses using an existing suite of long-duration earthquake ground motions that were each paired with a short-duration ground motion with similar response spectra. Results from analyses of 600 Magnitude-9.0 Cascadia Subduction Zone simulated site-specific ground motions for western Washington State were used in the formulation of a new testing protocol for steel jacket retrofitted reinforced concrete bridge columns that better accounts for expected demands in this region.

DOI:

10.14359/51745459


Document: 

SP-362_07

Date: 

June 5, 2024

Author(s):

Robert Lewis

Publication:

Symposium Papers

Volume:

362

Abstract:

The current mantra for our industry is “low carbon concrete,” but the question is – what do you actually mean by that? What is the benchmark you are using to say what is ‘low’– and how does that actually compare with what is being produced today? We’ve been making low-carbon concretes for decades – what we haven’t been doing is counting that carbon. Looking back at some history and at some recent projects, we can see that Low Carbon Concrete is certainly not rocket science and does in fact give us the durability and performance that we need for sustainability. The other side of the coin that we must be very wary of, in light of failures from the past, is that we produce concrete that is fit for purpose – making something that is ultra-green in the lab, but ultimately unusable in the real world serves no purpose and may even endanger lives. This paper shows a very small snapshot of the millions of cubic meters of binary, ternary, and quaternary cementitious blend concretes that have been used over the last 50 years, concentrating on more current examples showing that low carbon concrete is nothing new – it is already in major use.

DOI:

10.14359/51740877


Document: 

CI4509Brierley

Date: 

September 1, 2023

Author(s):

Gary Brierley, Joseph Klein, and Randall W. Poston

Publication:

Concrete International

Volume:

45

Issue:

9

Abstract:

This article is Part 2 of a two-part examination of the design and analysis of curved tunnel linings placed in direct contact with and restrained by the surrounding ground. While Part 1 focused on design considerations and a brief history of tunnel linings, Part 2 provides recommendations for tunnel analysis and proposes changes to ACI capacity calculations


Document: 

CI4507Goodwin

Date: 

July 1, 2023

Author(s):

Fred R. Goodwin and Ann Harrer

Publication:

Concrete International

Volume:

45

Issue:

7

Abstract:

Efforts to streamline document information


Document: 

CI4506Brierley

Date: 

June 1, 2023

Author(s):

Gary Brierley, Joseph Klein, and Randall W. Poston

Publication:

Concrete International

Volume:

45

Issue:

6

Abstract:

Tunnel linings are typically curved structures placed in direct contact with and restrained by the surrounding ground. The main objective of this two-part article is to explain how tunnel linings can be designed and analyzed in a reasonable and rational manner that is consistent with tunnel lining behavior. Part 1 focuses on design considerations and a brief history of tunnel linings.


12345...>>

Results Per Page 





ABOUT THE 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.

Edit Module Settings to define Page Content Reviewer