Unless the damage is caused by an official city street tree it is the fronting property owners responsibility for the maintenance and repair of there sidewalk. see Sec 5610 - Calif State Streets and Highway Code and Sec 12.04 of the Oakland Municipal Code. Oakland Code and Blight enforcement 510-238-3381 the more concerned neighbors that file complaints the better. It will take time and several phone calls. The call center will not do this for you.