Expeditious numerical capacity assessment in precast structures via inelastic performance-based spectra

Area of Science:

• Structural Engineering
• Earthquake Engineering
• Precast Concrete Structures

Background:

• Precast structures offer assembly efficiency but present unique seismic design challenges due to increased slenderness and pinned joints.
• Pinned joints in precast frames reduce energy dissipation and amplify second-order effects (P-Delta), impacting seismic performance.
• Traditional seismic design approaches may not fully capture the dynamic behavior of these specialized structures.

Purpose of the Study:

• To develop a simplified approach for assessing dynamic instability in precast hinged frames.
• To provide a tool for expeditious numerical capacity assessment during the initial design phase.
• To predict dynamic collapse and seismic limit states based on fundamental structural parameters.

Main Methods:

• Incremental nonlinear dynamic analysis using far-field ground motion records.
• Modeling precast structures as equivalent single-degree-of-freedom systems.
• Generating inelastic spectra based on structural parameters like height, column aspect ratios, and floor mass.

Main Results:

• The study yields inelastic spectra offering insights into structural capacity and response modification factors.
• Regression analysis shows polynomial expressions accurately fit median spectra (R²: 0.76-0.98).
• The developed tool aids in seismic performance-based design and assessment of precast structures.

Conclusions:

• The proposed simplified approach effectively assesses dynamic instability in precast hinged frames.
• The generated inelastic spectra serve as valuable metrics for seismic performance evaluation and design.
• This methodology supports engineers in designing safer and more resilient precast structures against earthquake actions.