AISC Bolt Coefficient

Bolt Group Coefficient Calculator using Instantaneous Center of Rotation Method

This app is a handy tool for Structural Connection Designers in designing bolted steel connections using the Instantaneous Center of Rotation Method. It replaces the lookup tables provided by the American Institute of Steel Construction in its AISC Manual in calculating the bolt group coefficient.

Without any tool, designing eccentrically loaded bolted connections using the Instantaneous Center of Rotation Method is a very tedious and time-consuming task. It involves calculating the bolt group coefficient and requires an intensive iteration since its mathematical formulation is not a closed-form solution. To make the process easier, the American Institute of Steel Construction, in its AISC Manual, provided lookup tables to determine the bolt group coefficients through interpolation. The coefficients made the design much easier and faster. The tables, however, have inherent limitations as far as variations in Load Angle, Load Eccentricity, and Bolt Geometry are concerned. The tables, generally, do not address these variations.

I created this app with one purpose: To address and compensate for those limitations.