An Improved Flange Bolt-Up Procedure Using Experimentally Determined Elastic Interaction Coefficients

Abstract

Uniform bolt stress (±2 percent) was obtained in a one-pass, tension-controlled, bolt-up procedure. This was done by experimentally determining elastic interaction coefficients. The coefficients were then used to solve for the required initial bolt loads that gave the desired final stresses. The procedure worked on two similar pairs of 16-in. class 300 flanges. Each flange set had different interaction, apparently due to surface gaps and misalignment. The procedure was repeated several times with a flat sheet gasket and without a gasket. The procedure and experimental results are described in detail.