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  • 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.

International Concrete Abstracts Portal

Showing 1-5 of 11 Abstracts search results

Document: 

SP300-06

Date: 

March 11, 2015

Author(s):

Jia-Liang Le and Zdenek P. Bazant

Publication:

Symposium Papers

Volume:

300

Abstract:

This paper reviews a recently developed finite weakest link model of strength of concrete structures, which fail under controlled load at macro-crack initiation from one representative volume element (RVE). The probability distribution of RVE strength is derived from the well-established transition rate theory and a hierarchical multi-scale transition model. The model predicts that the strength distribution of concrete structures depends on the structure size and geometry, transiting from a predominantly Gaussian distribution to a Weibull distribution as the structure size increases. It is shown that the present model agrees well with the strength histograms of Portland cement mortar measured by Weibull, which consistently deviate from the classical Weibull distribution. The importance of size effect for the reliability analysis of large concrete structures is then demonstrated through the analysis of the failure of the Malpsset Dam. Both the present model and the available experimental data invalidate the three-parameter Weibull distribution for concrete structures.


Document: 

SP300-01

Date: 

March 11, 2015

Author(s):

Victor E. Saouma

Publication:

Symposium Papers

Volume:

300

Abstract:

It has been well over thirty years since Hillerborg and Bazant presented their landmark papers (cohesive crack and size effect models respectively), and thirty years since the author submitted his Ph.D. dissertation on the application of fracture mechanics to concrete, (Saouma, 1980). Yet, since then, the practical applications of fracture mechanics to concrete structures have been few and far in between. In this paper, the author shares his experience in trying to apply fracture mechanics not only to concrete structures, but also to other \neighboring" materials such as polymers and ceramics, and he argues for improved collaboration with adjacent disciplines. The underpinnings (experimental, computational) of reported applications will be briefly highlighted. Finally, the paper concludes with a personal assessment of the current of state in the application of fracture mechanics to concrete structures and venture in some recommendations.


Document: 

SP300

Date: 

March 11, 2015

Publication:

Symposium Papers

Volume:

300

Abstract:

Editor: Christian Gaedicke

This CD contains 10 papers that were presented during a session sponsored by ACI technical committee 446 at the Spring Convention in 2012 in Phoenix, AZ. The papers focus on the implementation of fracture mechanics techniques in fiber-reinforced concrete, fiber-reinforced polymers, bonding, large structures, beam shear, pavements, and concrete deterioration. Where applicable, the papers compare modeling results with experimental tests.

Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-300


Document: 

SP300-07

Date: 

March 11, 2015

Author(s):

Roman Wendner, Alfred Strauss, and Drahomír Novák

Publication:

Symposium Papers

Volume:

300

Abstract:

The basis of all design codes and recommendations that are endorsed by engineering societies are safety concepts which have been formulated with the intent to meet a society’s safety demands. These demands are expressed in terms of failure probabilities, differentiating between structural safety and serviceability, accounting for the expected service life and the potential loss of life and assets. While in the last century safety formats were mainly based on experience, newer code developments are supported by fully probabilistic concepts and reliability engineering tools. Nonetheless, a realistic assessment of structural performance, and in consequence the expected service life, is in many cases impaired due to oversimplified design assumptions, the elastic determination of internal forces applying the principle of superposition, and a lack of understanding regarding the relevant stochastic models. While the ‘elastic’ design has merit in many design situations, its limitations are quickly reached if a realistic assessment of bearing capacity or serviceability are to be performed. Within this contribution the role of fracture mechanics in the reliability analyses of reinforced and pre-stressed concrete structures will be presented. After providing a review of the relevant concepts, examples are given to illustrate the significance of fracture mechanics as well as point out existing short-comings and the need for additional research.


Document: 

SP300-04

Date: 

March 11, 2015

Author(s):

Min Ook Kim and Amanda Bordelon

Publication:

Symposium Papers

Volume:

300

Abstract:

The influence of fiber-reinforcement in concrete is most apparent after cracking has begun propagating through the fiber-reinforced concrete (FRC). The size-independent “initial” or specific fracture energy is defined as the energy per unit area to create a new crack surface; while the “total” fracture energy can be defined as the size- and geometry dependent amount of energy per unit area required for a specimen to exhibit complete separation failure at which negligible traction occurs across the new surface. While the initial fracture energy is used to define un-reinforced concrete, the total fracture energy parameter has been successfully utilized for characterizing the benefit of low-volume fractions of fiber-reinforcement for pavement and slab applications. This paper summarizes the main issues associated with using total fracture energy for FRC relate to the methodology for obtaining and interpreting the fiber component contribution as well as understanding the test methods and modeling options available.


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