A Light Emitting Deformation Sensor was installed at a construction site to monitor and visualize deformation of retaining wall. As the deformation of the wall increases, the color goes from 1)blue, 2)light blue, 3)green, 4)yellow and finally 5) red to visually inform the state of the retaining wall to enable immediate and real-time safety evaluation.

Light Emitting Converter, LEC for short, has been developed since 2009 and used since early 2010. An LEC is a compact data converter that is capable of 1) converting analog signal from an arbitrary sensor connected to it into digital one, and 2) showing it by the color of LED (Light Emitting Diode) based on a pre-defined color scheme. A sensor to be connected to LEC can be chosen from a family of available sensors for measurement of deformation, strain, inclination, pressure, temperature, etc. The color scheme can be defined and changed later, if necessary, for each LEC-sensor pair by the control software installed on a PC. Up to 100 pairs of LEC and an arbitrary sensor can be connected to one personal computer. Each pair is given its own ID number and the data can be recorded on the hard disk with specified time interval. Five colors of choice can be used to visualize the measured data of arbitrary type.

Laser beam plane projected on a wall reveals its off-plane deformation instantaneously and beautifully.

LEC was installed at several locations monitoring and visualizing axial forces in strut beams, the inclination of retaining wall, the relative displacement of retaining walls, the inclination of an adjacent building near the construction site of AIIMS station. This project "SPECIAL ASSISTANCE FOR PROJECT IMPLEMENTATION (SAPI) : APPLYING THE MONITORING METHOD BY ON SITE VISUALIZATION AT DELHI METRO CONSTRUCTION SITES" was supported by JICA and was conducted in 2010.

This lecture was recorded on March 4th, 2020 at Kobe University in Japan.