Question

In a corroded state, SACS reverses the brace and chord, which results in higher UC. Corrosion is applied as a percentage by elevation, meaning that both brace and chord are affected by it. In fact, the entire jacket is within the same corrosion zone with 15% reduction applied. Please clarify.

Answer

According to Section 1.3.1 of the SACS Joint Can manual, the program determines chord and brace members based on their effective diameters after all reductions (such as corrosion) are applied. The member with the larger diameter is classified as the chord.

Since corrosion in the model was defined as a percentage of wall thickness, the thicker can lose proportionally more thickness, resulting in a slightly smaller effective outside diameter compared to the brace. Consequently, SACS correctly classified the corroded can as the brace, in accordance with item 1.3.1.