Title:
Equivalent Rectangular Stress-Block Approach for Moment-Curvature Response of UHPC Beams (Prepublished)
Author(s):
Chandrashekhar Lakavath, Pradyumna S. Suryakar, and S. Suriya Prakash
Publication:
Structural Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
equivalent rectangular stress block; fiber volume; flexure capacity; flexure database; moment-curvature (M-Phi) response; simplified design approach; structural design parameters; ultra-high-performance concrete (UHPC).
DOI:
10.14359/51751980
Date:
8/21/2026
Abstract:
While the layer-by-layer approach can accurately predict the moment-curvature (M-Phi) response of ultra-high-performance concrete (UHPC) beams, it is computationally intensive and cumbersome for designers. This study proposes a simplified equivalent rectangular stress-block method, aligning with conventional concrete design practices. The proposed method is validated using a database of 224 UHPC beams, including rectangular, T, and I-shaped sections, both prestressed and non-prestressed. The ratio of experimental to predicted moment capacities ranges from 0.95 to 1.13, with an overall average of 1.10 and a coefficient of variation of 16%, demonstrating good accuracy. Parametric analysis indicates that the maximum reinforcement ratio for singly reinforced UHPC beams ranges from 6 to 8%. To ensure ductile behavior and prevent compression-dominant failure in over-reinforced sections, it is recommended to provide compression-side reinforcement up to 50% of the area of primary tension reinforcement. The proposed approach offers a practical tool for UHPC flexural design suitable for researchers and practicing engineers.