Relative Displacement Sensing Techniques for Post Event Structural Damage Assessment: A Review

Relative displacement, which is displacement of a point on a structure with respect to its original location or an adjacent point on the structure that has also undergone movement, can be an effective indicator of post-event structural damage. Although quantifying relative deformations for post-event damage quantification is currently technically feasible, and of great potential benefit, the field remains undeveloped because of lack of knowledge among structural engineers of: 1) the enabling technologies, and 2) the performance limits of these technologies. The primary objectives of this paper are to review available techniques for measuring relative deformations, identify their limitations, and propose areas where further research is needed. Current methodologies are divided into remote and in-situ methods. The latter techniques are deemed most practically feasible and are surveyed in detail and critiqued. Suggestions for current challenges and research opportunities are proposed with emphasis on accuracy considerations, the need for creating a national database of structure information and methods for large scale automated assessment.