The city manager upon granting permission for such improvement shall at the same time specify the grade, width, thickness and material with other particulars. Permission shall only be granted upon written application of the owner and construction contractor and must show the lot or parcels of land upon which the improvement is to be made and the time allowed for its completion. The application shall embody a provision to the effect that applicants shall jointly and severally absolve the city from any loss or damage or claims of damages, incident to or in any manner flowing from such work, or attempted work, or improvement. (Prior code § 17-5).