and the erection of the door 10 is easier than would be the case if the beams 30 were preassembled to the panels moreover the configuration of the beams 30 is advantageous with regard to the stiffness of the beams and thus the increase in stiffness of the door panels 10 a 10 b 10 c and 10 d once the beams have been assembled and secured thereto however other configurations of door reinforcing beams and accompanying brackets may be utilized in accordance with the invention another advantage of providing a reinforcing beam 30 having a generally channel shaped cross sectional configuration together with the configuration of the support brackets 34 is that the brackets themselves aid in increasing the stiffness of the beams conventional sheet metal materials may be used in constructing the beams 30 and the brackets 34 and as mentioned previously conventional self tapping washer faced hex head screws for example may be used in securing the brackets and the beams to the door panels referring briefly to fig7 there is illustrated an alternate embodiment of a beam and bracket configuration for use with the door 10 and the door panels 10 a 10 b 10 c and 10 d respectively the reinforcing beam may for example be an i beam or an h beam in fig7 an i beam 130 is illustrated comprising a web 130 a and opposed flanges 130 b and 130 c the beam 130 is adapted to be supported by spaced apart brackets 134 one shown similar to the brackets 34 but modified with respect.