Dynamic Pressures on Tunnel Roofs due to Vehicle Passages

Pressure and proximity measurements made in a tunnel indicate that a typical vehicle passage produced on the tunnel roof an initial pressure increase of small magnitude, followed by a sharp and more substantial drop in pressure below atmospheric. The magnitude of the pressure drop was found to increase with smaller clearances between the vehicle top and the tunnel roof, consistent with the Bernoulli relation and the vehicle speed. The dynamic pressures potentially may have significant effects on the vibration and noise environments on the lower floors of “air rights construction” buildings that span highways.