A series of tests to ultimate failure was conducted on lattice type crane booms. The results of these tests, correlated to predicted mathematical values, demonstrated that ultimate load capacity can be predicted accurately and that SAE J987 “Crane Structures-Method of Test” results in proper but probably conservative ratings. The proposed SAE Recommended Practice, “Latticed Crane Booms-Analytical Determination of Stresses and Critical Loads,” appears to give reasonable ratings when compared to actual failure loads. This work and results presented suggest that the day may come when such structures can be rated based on ultimate or critical load rather than on critical stress.
