The present invention is directed to a method for installing or replacing tendons in prestressed concrete slabs of, for example, parking ramps and bridges. Prestressed concrete slabs contain steel tendons stressed so as to compress the slab before it is loaded. Such tendons can rust and break thereby releasing the stress level and weakening the slab. The present invention identifies a method for removing and replacing the damaged or deteriorated tendon with a new tendon which is then stressed to restore loading strength to the slab. The present method is also applicable for adding tendons to prestressed slabs to increase load capacity.