Tokio Marine Headquarters Building

Overview

The new headquarters of Tokio Marine & Nichido Fire Insurance Co. has been designed to replace the 1974 original buildings, which were approaching their end of life, in a fantastic location in central Tokio, facing the Imperial Gardens and extremely close to Tokyo station.

The building- which is approximately 100m tall and 86m per side in plan - is envisaged as a “forest” of wooden columns, connected by steel beams, designed to withstand severe seismic events, and will employ wood on an unprecedented scale both in terms of quantity and size, to the benefit of the building’s embodied carbon. The slabs will be a hybrid of CLT and concrete, whilst the columns measure more than 2x2m at ground level and are displayed on a grid of 12m x 12m, providing large flexibility for the internal space.

The facades are conceived to minimize solar gains during summer while maximizing incoming sunlight via a deep cavity double skin design that allows the timber of the columns to be readable by the public, but also integrate a dynamic shading system that allows views out. The building targets LEED platinum certification and will be extremely energy efficient in comparative terms to its surrounding.

The lower levels of the building are envisaged to be open and welcoming, like a ‘piazza’, with a sophisticated but highly transparent façade that will create a lightweight boundary between exterior and interior. The engineering of the cable truss façade takes into account the highly seismic location and aims at providing a very safe and secure envelope.

At the top of the building, 100m above the ground, a rooftop garden will provide a quiet and inspiring space for the employees to relax and to enjoy unique views of the city.

Highlights

• The building is the first example of this scale of hybrid timber structure and has gone through a very significant amount of studies in relation to its fire and structural safety, with the Client targeting to go ‘above & beyond’ the minimum required by Code.
• The deep cavity double skin also requires the integration of timber, which is not usually within the scope of façade contractors, but wants to make the most of prefabrication to facilitate a speedy erection and protect the rest of the timber structure.
• Weathering of the timber will differ between the exposed conditions and the elements protected behind the outer skin – with an aspiration to provide the most durable treatment to the timber in all conditions