Visit Report Keisoku Research Consultant Co.
The last excursion of the study trip was at Keisoku Research Consultant Co. They focus on observational methods in civil engineering and construction field.
Two employees of Keisoku gave a short presentation when we arrived at the Atomic Bomb Dome (building at the back of the photo). Unfortunately, it was crowded, and they were hard to understand in this buzzy place. However, they told about the survey that they conducted at the Atomic Bomb Dome.
In 1966 Hiroshima city council passed a resolution to preserve the A-bomb Dome. Keisoku is conducting soundness surveys every 3 year since 1992. They check the state of the dome including its deterioration due to aging. The survey consists of 4 steps:
1. Exterior survey: visual inspection of cracks, lifting and peeling of mortar, change in exposed reinforcing bars and their corrosion.
2. Sinkage measurement: examine sinkage by measuring the heights if the survey nails installed in the wall body of the dome.
3. Vertically measurement: check the tilt of the dome by measuring the installed survey nails.
4. Permeability examination: examine the effects if waterproof material applied on the surface of the wall body of the dome for surface protection.
In all those surveys no big damages were found. In 2002 they repaired small corrosion and deterioration problems.
Keisoku has great mapping skills. They fly with drones and use paragliding with 3D lasers technique and a high definition camera system. They produce a Structure from motion map (SfM) with thousands of pictures and laser data. This SfM is a digital map where you can reconstruct the camera position in a 3D map.
They can create a high definition map were every millimetre is a pixel. The biggest project they had executed is the mapping of Gunkujima island and old mining place which is abandoned in 1974. They recreated a 3D map with original buildings for the museum of Gunkujima. This technique can also be used for measuring deterioration of sluices, dames and riverbanks. A few examples are stated below:
Unknow named dam: Thy flew with drones next to a dam and made about 21800 pictures. They formed a SfM with all the data. The engineers could zoom into the dam from every angle. With this technique the smallest signs of corrosion could be seen.
Unknown named bridge: They flew with a paragliding machine for 4 hours next to the bridge. A SfM is created about 2 km long and 100 meters wide.
Earthquake damage measurements: Keisoku made a SfM of a dam for restauration. 2 Years later a massive earthquake occurred. They made a SfM after the earthquake. They compered the 2 SfM models to measure the displacements of the dam.
Keisoku is a private company which conduct the measurements themselves. They give advice to other companies, but they don’t carry out any construction works. Keisoku organised a great day for our study tour with a visit to the A-Bomb Dome, an origami workshop and an interesting presentation. We learned about 3D mapping and different measurements. An extra thing we learned is that a translate machine will work great if you don’t speak English, but you must speak English.