MINI SESSION: Testing and Reliability of Structural Plain Concrete

Sunday, November 3, 2024  1:00 PM - 2:00 PM, Franklin 8

The mini session will explore the closely related topics of testing and reliability as applied to structural plain concrete. Load and resistance factors in building codes are calibrated to deliver the required reliability defined in ASCE-7. Given reliability is highly depending on the testing and variably the topics must be considered together.
Learning Objectives:
(1) Understand the the challenges and benefits of direct tension testing in plain concrete applications;
(2) Compare and contrast tension and bending testings for structural plain concrete;
(3) Understand basic approach for structural reliability;
(4) Understand the interrelation between variability in testing and design load and resistance factors.

Failure Not an Option: Testing of Plain Concrete for Mass Concrete Applications

Presented By: Ernest Schrader
Affiliation: Schrader Consulting
Description: Testing of plain concrete and how we use that info for design of dams where failure is not an option. Will include discussion of long term tensile creep testing of large samples, and using that info as part of long term cracking analysis for unreinforced concrete and testing shear strength at variable confining loads.

Reliability-Based Calibration of Strength Reduction Factors for Plain Concrete

Presented By: Andrea Kouame
Affiliation: Auburn University
Description: Plain concrete is used for various structural elements that contain no reinforcement or less reinforcement than specified by the American Concrete Institute (ACI) Building Code. There have been significant developments in the concrete industry and a continuous growing interest in structural plain concrete. However, no major changes were made to the relevant ACI 318 Code since 1989. The current ACI 318 design provisions approximate the flexural strength of plain concrete from the compressive strength, even though concrete fails primarily in tension rather than in compression. Compression-based design appears to be conservative as large factors of safety were used to prevent failure; it also inhibits the wider use of structural plain concrete because of an increased cost in constructability. Hence, there is an urgent need to investigate the flexural performance of plain concrete for linear elastic design and update the ACI design provisions as they have a considerable impact on the construction of plain concrete components and structures. The objectives of the project are to statistically evaluate parameters for plain concrete for various limit states including compression, tension, and shear, and to determine the associated strength reduction factors using a reliability-based calibration. The statistical parameters and reliability-based calibration for plain concrete can result in the development of higher-performance concrete and safer design of plain concrete components and structures, which will be beneficial to several ACI committees. Furthermore, those may affect the costs and improve the competitive position of concrete versus other materials.