ABSTRACT
Special dual-purpose sensors like that shown in
Figure 1 can be placed across a crack to simultane-
ously measure both long-term (climatological or
environmental) and vibratory changes in crack width.
The two factors are distinguished by the time spans in
which they occur. Vibratory response is captured by
recording crack response to ground motion at 1000
samples per second. Long-term climatologically-
induced responses are captured with measurement of
crack response sampled every hour over the course
of days and months. This direct measurement of
the change in crack width, termed “crack response”
applies directly to cracks and requires no reliance
upon empirical guidelines.
