A rock bolt includes a hollow body and a gap along a length of the hollow body. At least one strain gauge is affixed to an inner surface of the rock bolt and is accessible from the gap. The rock bolt may include a data logger within the hollow body and coupled to receive signals from one or more strain gauges, and to record these signals in a memory. The data logger may comprise a data port adapted to be accessible from the outside of a bore hole into which the rock bolt is inserted. The data logger also may include at least one of a visual and auditory alarm. A graphic user interface software program can be used to download data from the data logger and set certain operating parameters of the data logger.