In strength design of bolted joints, it is important to estimate increase of bolt tensions caused by external loads. "Load factor" is an index expressing how large an additional tension is to an external load. In this report, this index is examined using experimental results, calculated results from the method of the VDI 2230 guideline and calculated results from FEM analyses. It is known that these three kinds of results show similar inclinations, but not always agree well. The values from two kinds of calculations are greater than the experimental values. Additionally, spring constants of bolted joints are discussed as a subject concerned.
