Modeling Tower Crane Operator Visibility to Minimize the Risk of Limited Situational Awareness

Abstract

Many construction fatalities involving cranes and ground workers are caused by contact with objects and equipment, in particular being struck by crane loads and parts. One of the main risks in operating a tower crane is the limited visibility of the crane operator. An approach is presented that aims at increasing the situational awareness of a tower crane operator by aligning enhanced understanding of construction site layout with increased operator visibility of ground level operations. The developed method uses sensors to collect two data types, as follows: (1) a laser scanner measures the as-built conditions and geometry of a construction site, and (2) real-time location-tracking technology gathers the mostly dynamic location of workers on the ground. Several algorithms are presented to (1) identify blind spaces from the collected point cloud data that limit the visibility of a crane operator, (2) process real-time location-tracking data of workers on the ground, and (3) fuse the resulting data to create information that allows a quantitative assessment of the situational awareness of a tower crane operator. Results to a field trial are presented and show that a tower crane operator using the developed approach can increase understanding of where and when occluded spaces and ground-level operations occur. The developed methods for creating safety information from range point cloud and trajectory data is a promising approach in significantly improving the currently unsafe operation of tower cranes, one of the most utilized pieces of equipment in construction.