Experimental verification of the effect of reducing deformation of temporary bridges used for disaster relief under active control

Abstract

This study evaluates the impact on bridge dynamic responses of bridge with Neutral Equilibrium Mechanism (NEM) control as virtual pier of bridge. Developed by our research team in 2017, NEM technology has led to several invention patents and publications. It effectively reduces bridge deformation, enhances structural vibration frequency, and allows for smaller cross-section designs, improving construction and disaster relief capabilities. To validate its practical effects, dynamic experiments were conducted using a 4.594-m large-scale aluminum alloy bridge model. We compared displacement responses at the bridge midpoint under dynamic moving loads in both controlled and uncontrolled conditions. Results showed that, without control, maximum displacements ranged from 3.6691 mm to 11.8177 mm, while with NEM control, this was reduced to just 0.1303 mm, marking a 97.8% reduction in vertical displacement. A self-developed Digital Image Correlation (DIC) method was used to mitigate noise and ensure precise displacement measurement, enhancing the reliability of the results. The study also assessed the impacts of control gain, load magnitude, and load speed on performance, providing recommendations for adjustments. These findings confirm NEM technology’s effectiveness in reducing bridge deformation, though further optimization of control gain and system design is needed to avoid system divergence. Future research should focus on integral response length to enhance system performance and stability.