Existing Precast Channels, Dated 1958

[bakeronmac]

I am reviewing an existing structural drawing dated 1958. The first floor system is constructed of a one-way, precast concrete channel slab system (10" deep with a 2" concrete topping). The channels are shown to be spaced approximately 2'-6" on-center. The drawings also designate the concrete members as LC-5's, LC-6's, and LC-8's.

I am searching for the design capacity of these existing members. Is there a reference guide with design tables for these particular members?