If properly done, the values will remain the same, but the signs will differ. You must be consistent with whatever sign convention you choose to adopt, otherwise, errors will come in. However, it is important to note that what matters most in sign conventions is consistency. This is mainly due to variations in the selection of positive and negative coordinates.įor instance, most Indian and American textbooks will adopt the conventional cartesian coordinates system, and plot all positive bending moment upwards, and negative moments downwards, while most British and Scandinavian textbooks will plot positive moment downwards, and negative moments upwards. It is very common for people to define and state their sign convention before proceeding with any structural analysis problem. The three most prominent internal forces in structural analysis calculations are the bending moment, shear force, and axial force. If you do not understand sign conventions properly, it will be difficult to make significant progress in mastering structural analysis calculations. As a matter of fact, it is always a pausing point for all civil engineering students being introduced to structural analysis for the first time. Understanding sign conventions is one of the most important aspects of structural analysis.
