What are the connection requirements for built-up beams?

There are no specific provisions for connections for built-up beams. WCD#1, Details for Conventional Wood Frame Construction outlines the following general criteria:

Beams and girders are of solid timber or built-up construction in which multiple pieces of nominal 2-inch thick lumber are nailed together with the wide faces vertical. Such pieces are nailed with two rows of 20d nails-one row near the top edge and the other near the bottom edge. Nails in each row are spaced 32 inches apart. End joints of the nailed lumber should occur over the supporting column or pier. End joints in adjacent pieces should be at least 16 inches apart, Figure 15.

There is a General FAQ dealing with increased buckling capacity for built-up beams:
Is there a design method for increased buckling capacity of built-up wood beams?”