STEEL PROPERTIES USED TO MANUFACTURE WOOD TRUSS METAL CONNECTOR PLATES

A study was conducted by surveying members of the Truss Plate Institut e (TPI) on properties of steel used in the production of metal connect or plates. Three out of eight truss plate manufactures (TPMs) responde d with summary statistics, and one of the three provided raw data for both ASTM grade B (1993a) and grade 60 (1993b) steel coils. Statistica l distributions were fit to the data and several conclusions were draw n. Ultimate strength of steel is an important attribute for modeling f ailure of a metal-plate-connected truss joints. A truss plate manufact urer could feasibly sample a coil of steel, and find that the ultimate and yield strengths are slightly below minimum specified standards. A truss simulation aimed at establishing minimum performance in a load test should include steel that is close to minimum specified ultimate strength. If average performance of populations of trusses is of inter est, the steel properties should be modeled as random variables. Yield strength and ultimate strength of the samples were found to be positi vely correlated for both grade B and grade 60 steel. The estimated cor relation coefficients ranged from 0.46 to 0.79.