Tridimensional laser scanning to retrieve engineering site drawings. The experience of the Brussels Park bunker rehabilitation project

A project aims to rehabilitate the Brussels Park bunker. The objective is to transform a disused place in a high-tech center according to current construction standards. Thus it is essential to base the rehabilitation strategy on correct plans. The original plans, dating from 1939, have been partially retrieved. However, they are incomplete and do not consider the transformations made over time. A topographic survey has produced a preliminary plan, but it contains inconsistencies in both geometry and disposition of the different rooms. To obtain documentation and measurements, a survey was carried out using a 3D laser scanner. In addition to complete plans, this work accumulated necessary information for virtual visits. Different processings were applied on data to obtain detailed plans, confirming the inconsistencies identified in 2010. This paper includes the results obtained and highlights added values of 3D scanning for recovering plans of existing structures.