Fiber-Reinforced Concrete—From Fresh Properties to Structural Design: New Tools, Guides, and Reports-An Overview of the Document ACI 544.8R-16 Report on Indirect Method to Obtain Stress-Strain Response of Fiber-Reinforced Concrete (FRC) (PDF)

An Overview of the Document ACI 544.8R-16 Report on Indirect Method to Obtain Stress-Strain Response of Fiber-Reinforced Concrete (FRC) (PDF)

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Pdf Summary

The ACI 544.8R-16 report by Barzin Mobasher discusses the indirect method to obtain the stress-strain response of Fiber-Reinforced Concrete (FRC), which enhances ductility, tensile strength, energy absorption, and provides improved seismic resistance. FRC reduces construction time, labor, and long-term maintenance due to its resistance to corrosion damage.<br /><br />The report focuses on testing methodologies such as flexural and tensile tests to measure the strength and toughness of FRC. It mentions ASTM standards C 1399 and C 1609 for evaluating the residual strength of FRC. The text discusses the mechanics of the toughening modes of FRC influenced by the fibers' type, length, properties, and content.<br /><br />Key objectives include correlating testing, data analysis, structural analysis, and design to facilitate the development of serviceability design procedures. Inverse analysis is advocated to derive equivalent material properties from empirical tests, measuring load and deformation to compute the stress-strain response.<br /><br />The document emphasizes using a simplified design approach analogous to Whitney’s stress block diagram and delves into the design philosophy for flexure. It presents models for strain softening and an approach to design via the flexural response of beams using closed-form equations.<br /><br />Tools and software including an Excel spreadsheet are mentioned to assist in the calculation of material properties and design approaches for both three and four-point bending samples. The report concludes with the provision of closed-form equations for load-deflection response and moment-curvature diagrams to estimate moment capacity. This serves as a fundamental tool in designing FRC structures, sensitive to post-crack tensile strength but less so to compressive-tensile strength ratio.

Keywords

Fiber-Reinforced Concrete

stress-strain response

ductility

seismic resistance

flexural tests

ASTM standards

inverse analysis

design procedures

strain softening

moment capacity