Mobile Point Cloud Assessment for Trench Safety Audits

Fatalities resulting from cave-in hazards during excavation work in the United States account for 48% of the trench fatalities in construction every year per Occupational Safety and Health Administration (OSHA) data. Recent trends indicate that fatalities from trench and excavation hazards in the US are increasing. Often the experience of safety inspectors and/or the designated competent person (CP) for trenching and excavation is vital when assessing sloping measurements with approved engineering survey tools. The degree of accidents, however, allows the conclusion that proper assessment and/or protection of excavation sites is not performed sufficiently in the field, or safety coordinators and/or adequately trained CPs are not on hand when needed. While existing assessment processes and protection methods are reviewed for potential improvement, this paper proposes a new compliance assistance prototype that incorporates state-of-the-art technology. The proposed prototype creates: (1) mobile field data acquisition with low-cost photogrammetric devices to capture point cloud surveys of the as-built conditions of trenches, and (2) computational data processing to automatically extract trench height, width, and slope values. Early results to field-realistic experiments promise useful applications of the developed prototype for safety coordinators or adequately trained CPs.