Measurement of slip coefficient for grade ASTM A588 steel [report]

Stankevicius, Joseph; Kulak, Geoffrey L.; Georg, Josi; Grondin, Gilbert Y.
An investigation of the slip coefficient of Grade ASTM A588 steel was carried out using a total of 99 tension double lap splice joints. The test parameters included the effect of steel heat, faying surface condition, level of bolt pretension, bolt hole diameter (regular size and oversize) and bolt hole fabrication method on the slip coefficient. The test specimens consisted of 1/2-in. or 5/8-in. main plates with double splice plates of the same thickness as the main plates. One end of the test
more » ... ne end of the test specimens was prepared with a one-bolt joint and the other end with two bolts. Pre-calibrated centre-hole load cells were used to measure the bolt pretension directly, which was introduced by turning the nut. The double lap splice joints were loaded in axial tension and the load and deformation were continuously monitored in the test until either bolt shear failure or plate bearing failure took place. The test results showed no significant effect of the level of bolt pretension per se, bolt hole fabrication, or bolt hole diameter on the slip coefficient. However, the test results suggest that the preparation of the faying surface has a significant effect on the slip coefficient; as-received faying surfaces with loose particles removed before joint assembly showed a lower slip coefficient than degreased faying surfaces. The steel heat also seems to affect the slip coefficient. The results were close to the mean slip coefficient proposed in Specification for Structural Joints Using ASTM A325 or A490 Bolts [RCSC 2004] for clean mill scale faying surfaces, but showed a substantially higher slip coefficient than determined in another study on A588 steel ]. ii
doi:10.7939/r3bn0h fatcat:hu37ka4u3fgfnpo6fqm7gtunia