Quantifying Material Uncertainty in Seismic Evaluations of Reinforced Concrete Bridge Column Structures

Area of Science:

• Structural Engineering
• Earthquake Engineering
• Materials Science

Background:

• Seismic performance evaluations often use deterministic models, neglecting inherent uncertainties.
• Variability in mechanical properties of reinforcing steel and concrete constitutes a significant material uncertainty in reinforced concrete structures.

Purpose of the Study:

• To analytically quantify the impact of statistical variability in material properties on the seismic response of reinforced concrete bridge columns.
• To assess the influence of ASTM A706 Grade 60, 80, and 100 reinforcing steel and normalweight concrete property variations.

Main Methods:

• Analytical investigation of reinforced concrete bridge column seismic response.
• Statistical analysis of material property variations (reinforcing steel and concrete).
• Quantification of the coefficient of variation (COV) for drift and force demands.

Main Results:

• Drift response COV ranges from 0.1 (low-to-moderate ductility demands, drift ratio < 5%) to 0.3 (larger ductility demands).
• Force demand COV is lower, ranging from 0.05 to 0.1.
• Material uncertainty significantly affects seismic performance metrics.

Conclusions:

• Material uncertainty in reinforcing steel and concrete properties must be considered in seismic performance assessments.
• Incorporating material uncertainty can be achieved through a limited number of additional analyses.
• This approach enhances the reliability of seismic evaluations for reinforced concrete structures.