Vibration Serviceability of Footbridges: Classical vs. Innovative Material Solutions for Deck Slabs

Area of Science:

• Civil Engineering
• Structural Engineering
• Materials Science

Background:

• Human-induced vibrations are critical for footbridge design, affecting serviceability and comfort.
• Traditional reinforced concrete (RC) slabs have limitations in dynamic performance.
• Glass fiber-reinforced polymer (GFRP) composites offer innovative solutions for structural components.

Purpose of the Study:

• To compare the human-induced dynamic performance of footbridges with RC versus GFRP deck slabs.
• To assess resonance risk, vibration serviceability, and comfort criteria for different slab materials.
• To investigate the impact of higher harmonics of pedestrian forces on GFRP-equipped footbridges.

Main Methods:

• Numerical studies were conducted on two types of footbridges: cable-stayed and beam structures.
• Two variants were analyzed for each bridge type: one with RC slabs and one with GFRP slabs.
• Dynamic performance, natural frequencies, resonance risk, and human-induced accelerations were evaluated.

Main Results:

• GFRP slabs resulted in higher fundamental frequencies and reduced resonance risk compared to RC slabs.
• GFRP slabs led to significantly higher human-induced accelerations, especially in lightweight beam structures.
• Higher harmonics of pedestrian forces significantly impacted GFRP footbridges' dynamic behavior, unlike RC ones.

Conclusions:

• GFRP footbridges generally offer improved resonance resistance over RC designs.
• Lightweight GFRP structures may face challenges meeting vibration serviceability criteria due to amplified responses.
• The influence of higher harmonic forces on GFRP footbridges necessitates detailed dynamic analysis during the design phase.