Deformation Monitoring of a Building Structure Using a Motion Capture System

Conventional 1-D or 2-D displacement sensors are occasionally used to measure the deformation of a structure. However, a motion capture system (MCS) can measure the 3-D movements of markers attached to a target structure with high accuracy and a high sampling rate. Because markers can be easily attached to a structure, an MCS is useful for monitoring the dynamic motions of complex structures, such as buildings, using multiple markers. This study proposes a deformation measurement method for building structures using an MCS. The suggested measurement method consists of four stages: 1) setup of the MCS; 2) data acquisition; 3) coordinate transformation into a structural coordinate system; and (4) generation of the deformed shape. The feasibility of the suggested MCS-based measurement method was validated using a free-vibration test of a three-story experimental frame model. The displacement and deformed shape that were measured using an MCS were compared to the displacement and deformed shape measured using a laser displacement sensor, which is a conventional displacement sensor. The comparison results indicated that the MCS can overcome the limits of 1-D displacement sensors and easily and accurately obtain the deformed shape of a structure.