All bridges acquired pursuant to this chapter by this state jointly with the state of Pennsylvania, according as the bridges have a terminus in said states, respectively, shall be and remain in the charge and custody of any board or official that the respective governors of said states may designate.

Such bridges and the immediate approaches thereto shall be maintained jointly by the two states in equal proportions, and shall be rebuilt, constructed, reconstructed and maintained and kept in constant repair and rebuilt when destroyed, and the expense incident thereto shall be borne equally by the two states; provided that appropriate concurrent legislation for the same purpose be enacted by the state of Pennsylvania.