Mariog,

You quote from Appendix S, and quite right, residual bolting stress will usually be far higher than the design stress value, and in reality it must be.

The incompatability I referred to in another post does not concern weak bolts. The common case of bolt-up stress exceeding the allowable when operating stresses re acceptable generally results from a high radial stress.

Using a higher than 'design stress' value for bolt allowable stress will only make this condition worse due to W = 0.5(Am+Ab) x Sb. However it's not a real problem as we all are aware.