ZHANG B Q, LI J Y, PAN Q F, et al.Dynamic responses of a beam to moving loads on an elastic foundation overlying voids[J].Journal of Henan Polytechnic University(Natural Science) ,2024,43(4):162-168.

doi:10.16186/j.cnki.1673-9787.2023040061

Received:2023/04/27

Revised:2023/08/11

Published:2024/07/05

Dynamic responses of a beam to moving loads on an elastic foundation overlying voids

ZHANG Bingqiang1, LI Jiayao1, PAN Qinfeng1, HUANG Zhibin2

1.School of Civil Engineering，Fujian University of Technology，Fuzhou  350118，Fujian，China;2.China Railway 24th Bureau Group Fujian Railway Construction Co.， Ltd.，Fuzhou  350113，Fujian，China

Abstract: Objectives To explore the influence of local voids due to plastic deformation or rainwater erosion on the pavement dynamic responses to moving load，  Methods a concrete pavement with local voids was simplified as an elastic beam spanning a void， and the equation for the dynamic responses of the elastic beams on the Kelvin foundation with local voids under moving loads was established. The modal superposition method was used to solve the dynamic responses of a beam overlying voids under moving loads. Compared with the calculation results from the existing theoretical methods， the proposed analytical solutions for the dynamic response of foundation beams were verified. The influences of the parameters on the dynamic response of the beam were studied， including the moving speed of the load， the width of local voids underlying the beam， the elastic coefficient of the foundation， and the bending stiffness of the beam.  Results Neglecting the influence of local voids underneath the beam caused the theoretical results to be less than the true data. The local voids underneath the beam had a significant influence on the dynamic responses of the beam directly above the void， while the influence on the beam outside the void was minor. As the bending stiffness of the foundation beam decreases， the influence of the void width on the maximum displacement of vibration of the foundation beam at the midpoint became significant. When the void width was 2/9 of the length of the beam，the maximum vibrating displacement at the midpoint of the beam was about 5 times of that without considering the void underlying the beam. Increasing the bending stiffness of the beam and the elastic coefficient of the foundation could reduce the vibrating displacement at the midpoint of the beam. However， the effect of improving the foundation elastic coefficient was minor when the void width underlying the beam was 1/3 of the length of the beam.  Conclusions The local voids underneath the concrete pavement exacerbate the vibration of the pavement under vehicle load.

Key words:beams overlying voids;dynamic response analysis;modal superposition method;moving load;viscous foundation