Mechanical response design of arch seat foundation under complex traffic loading

Area of Science:

• Civil Engineering
• Geotechnical Engineering
• Structural Engineering

Background:

• The mechanical response of arch seat foundations in extra-long-span arch bridges under complex traffic loads remains incompletely understood.
• Understanding these responses is vital for ensuring bridge safety and longevity.

Purpose of the Study:

• To develop a field-scale three-dimensional finite element model (3D FEM) of an arch seat foundation for a large-span arch bridge.
• To analyze the foundation's mechanical response under various complex traffic loads.
• To identify critical areas for reinforcement and monitoring.

Main Methods:

• Development of a field-scale 3D FEM based on a real-world large-span arch bridge project.
• Simulation of complex traffic loads, including temperature gradients, braking forces, and wind loads.
• Detailed analysis of stress distribution, pile load transfer, and surrounding rock's stress-strain behavior.

Main Results:

• Maximum tensile stress is concentrated in the connection zone between the arch abutment cap and arch springing.
• Tensile forces are highest at the top of vertical piles, with maximum bending moments at pile heads.
• Plastic strain and settlement are concentrated in interconnected regions of the arch springing, cap, and main beam.

Conclusions:

• Reinforcement design optimization is critical at the arch springing, cap, and main beam connections.
• Long-term stress and strain monitoring are essential for early detection of potential issues.
• Mitigation strategies for microcrack initiation and fatigue propagation are necessary for structural integrity.