Autonomous Crack Measurement for Comparison of Vibratory Compaction Excitation and Climatological Effects

Abstract : Establishment of the fragility of historic structures near rights of way often produces costly delays in construction. Autonomous Crack Measurement (ACM) of micro meter response of cracks can be employed to assess the potential for adjacent construction activities to cause cosmetic cracking in both historic and non-historic structures. ACM measurement of micro meter crack width changes caused by long term climatological and vibratory roller compaction adjacent to an adobe (native mud brick) structure is employed to illustrate the use of micro meter changes in crack width as a tool for structural health monitoring. It was found that long term or weather-induced crack responses are much larger than those induced by high frequency vibratory compaction, even at US and above European regulatory limits. At more typical levels the potential for formation of cosmetic cracks in newer adobe structures are negligible. Thus for this class of adobe structures, normal regulatory guidance is sufficient for construction or operation of transportation facilities.