In which scenario would the use of steel shims be necessary?

The use of steel shims is particularly necessary when grouting is postponed, as it ensures that the structural components remain properly aligned and supported during the delay. When grouting is planned, it typically helps to fill voids and secure various structural elements in place. If this process is delayed, steel shims can be deployed to provide temporary support and maintain the integrity of the installation until grouting can be completed. This approach helps to prevent misalignment and maintains the load-bearing capacity of the structure.

In contrast, other scenarios do not typically require shims in the same way. For instance, during anchor rod installation, the focus is more on ensuring that the rods are properly set in concrete or other materials, and minimal adjustment is usually required. Similarly, when cutting openings into beams, the structural integrity is often assessed and adjusted through different methods. The installation of bracing systems may involve aligning components, but it is typically accomplished through mechanical means, rather than relying on shimming. Therefore, the context of postponing grouting is the key reason steel shims come into play in that scenario.