An efficient approach to obtain optimal load factors for structural design

Area of Science:

• Structural Engineering
• Reliability-Based Design
• Optimization Methods

Background:

• Current structural design codes rely on calibrated load factors to ensure safety.
• Achieving a consistent level of structural reliability is crucial for performance and safety.
• The Mexico City Building Code (RCDF) provides specific load factor recommendations.

Purpose of the Study:

• To develop an efficient optimization approach for calibrating structural load factors.
• To ensure structural reliability indices are as close as possible to a target value.
• To propose optimal load factors for reinforced concrete elements based on the RCDF.

Main Methods:

• Parametric numerical analysis of reinforced concrete elements.
• Monte Carlo simulation technique for reliability assessment.
• Optimization procedure to calibrate load factors for dead and live loads.

Main Results:

• Optimal load factors were determined for various failure modes (flexure, shear, torsion, compression).
• The proposed optimal load combination was analyzed for short and slender reinforced concrete elements.
• The structural reliability of the proposed combination was compared against the RCDF recommendations.

Conclusions:

• The developed optimization approach provides a method for calibrating load factors to achieve target reliability.
• The proposed optimal load factors offer a potentially more reliable design basis than current RCDF recommendations.
• This methodology can be applied to various structural elements and failure modes.