elevator casing access door

huangyhg

elevator casing access door
i am looking at a casing for a bucket elevator and i am trying to find material on designing an access door in the casing.  the bucket elevator is 4'6" x 1'8".  they are wanting to install a 5'x3' door on both sides of the casing.  is there any recommended material?

more info needed. is this round? what is going to be lifted? how far? what is the door for?   
richard a. cornelius, p.e.
the elevator shaft is rectangular 4'6" x 1'8".  the elevator lifts lime pebble and the elevator is approx. 128' tall.  they would like to cut an access door near the bottom of the elevator.  they would like the door to be installed on both sides of the casing which the width of the side is 4'6".  they would like a 5' tall by 3' wide door.  i contacted the supplier because i found draings of access doors on elevators but would like to calculate double check the stiffeners required around the opening.  i found material on a silo (round) but i am uncertain about calculations on the rectangular.