Monday, 7 August 2017

Technical Trip to Shinjuku Mitsui Building in Tokyo, Japan

Hello Everybody,

In this post, I would like to share some of the interesting photos taken during the technical visit to Shinjuku Mitsui Building which is located in Nishi-Shinjuku area in Tokyo, Japan.

The Shinjuku Mitsui Building is a high-rise building in Nishi-Shinjuku area in Tokyo and it is owned by Mitsui Fudosan. It is one of the 10 tallest buildings in Tokyo and was the tallest building in Japan from September 1974 until March 1978. The photo of the skyscraper is shown in the figure below.

Figure 1. Shinjuku Mitsui Building

The building was subject to substantial long-period ground motion during Great East Japan Earthquake on March 11, 2011, and was observed to sway approximately 2 meters. Although the building was a structurally rated, Ministerial-approved building that provided a high level of safety, and its seismic performance was proved to be fully adequate during the earthquake, there were increased concerns among tenants about the safety and security of the building since the earthquake. Therefore, the building owner decided to upgrade the structure by installing Tuned Mass Dampers (TMDS) to further strengthen the structure against even stronger earthquakes and to provide peace of mind for the occupants.

Figure 2. Sketch of Shinjuku Mitsui Building with TMDs

TMDs are simply gigantic pendulum-like counterweights that are placed on the top of the structure and tuned to pull a building’s mass in the opposite direction of the prevailing vibrations. So when the ground beneath a foundation moves laterally—either because of the wind or seismic activity—the counterweight moves in the opposite direction, taking the structure with it. 

Figure 3. Photo of a Tuned Mass Damper on the top of Shinjuku Mitsui Building.

The video below simulates the building behavior during the earthquake with and without TMDs.

Video 1. Earthquake simulation of Shinjuku Mitsui Building with and without TMDs

Installing TMDs to the Shinjuku Mitsui Building cost approximately $50 million.

In the below photo me and three other ESRs are on the roof of the Shinjuku Mitsui Building.

Figure 4. ESRs on the top of the Shinjuku Mitsui Building. From left to right - Me (ESR 7), Matteo Vagnoli (ESR 9), John James Moughty (ESR 10), Antonio Barrias (ESR 11)

Stay Tuned!

Bridge Visual Inspection Using Robotic Camera

Hello Everybody,

During my trip in Japan, I had a chance to attend a bridge visual inspection demonstration using a robotic camera devise which is designed by Hitachi Industry & Control Solutions, Ltd for use at locations where close visual inspection is difficult, such as inspection of bridge soffits, or around bearings. Using pole units, it facilitates the process of positioning a camera at a height within visual range, conducting inspections, measurements, and acquiring video recordings. The photo provided below shows the devise mounted on an elevating type pole.

Figure 1. Bridge inspection robotic camera mounted on an elevating type pole unit.

Two pole units are available, the Suspending Type and the Elevating Type. By installing the base of the pole unit on a parapet, the suspending type can extend downwards to a maximum of 6.0m. In contrast, using a stand placed on the ground, the elevating type pole unit can extend a camera upwards to a maximum of 10.5m. The camera can be operated remotely from a tablet computer using wireless communications. On the video provided below, a site personnel explains how the system works.

Priorly, the company began development of robotic pole cameras for inspection of house roofs and similar applications in 1995, and they are now in wide spread use for bridge visual inspection activities.

The distance from the camera to the object is measured using a laser range finder mounted on the camera. Sizes on the surface of the object are assessed according to the distance measured, and an appropriately-scaled crack scale/ruler or L-square can be displayed on the operation tablet. When the engineer performing the inspection is unable to approach closer to the object, this function enables measurement of crack widths, lengths, and other damage. By adjusting the crack scale on the tablet, you can measure the actual width of the crack. In the below video technician measures the crack width using the system which is about 0.5mm thick.

I also attended some other technical visits during my trip in Japan which I will share in the following posts.

Stay tuned!