When measuring bottom side rail web inward deformation, what reference point should be used?

When measuring inward deformation of the bottom side rail web, using the undamaged area as a reference point is critical because it provides a baseline that accurately reflects the original structural integrity of the rail. This allows for a clear assessment of how much deformation has occurred due to damage or external forces.

Using a point that is undamaged ensures that any measurements taken will represent actual deformation rather than variations caused by existing imperfections or damage elsewhere. It avoids introducing additional variables and ensures consistency in measurement, which is vital for evaluating safety and potential repair requirements.

Other reference points may not provide the same level of accuracy. For example, measuring from a damaged area could lead to skewed results that do not reflect the true state of the rail. Similarly, using the reference line or corner fitting might incorporate elements that are not directly associated with the deformation itself, leading to inaccuracies. Thus, relying on the undamaged area guarantees that the measurements are a reliable indicator of the rail's current condition.