Tokio Marine Headquarters Building

Overview

The new Tokio Marine & Nichido Fire Insurance headquarters is designed to replace the original 1974 buildings, which were approaching the end of their service life. The site occupies a prime location in central Tokyo, facing the Imperial Palace East Gardens and within walking distance of Tokyo Station. 

Hybrid Timber Structure & Seismic Design 

The building, which is approximately 100 meters tall and 86 meters per side in plan, is envisaged as a “forest” of wooden columns connected by steel beams and designed to withstand severe seismic events. It will employ wood on an unprecedented scale, in both quantity and size, to reduce embodied carbon. The slabs will be a hybrid of cross-laminated timber (CLT) and concrete, while the columns will measure more than 2 by 2 meters at ground level, arranged on a grid of 12 by 12 meters, providing significant flexibility for the internal space. 

Façade & Whole-Building Environmental Performance 

The façades will minimize solar gain during the summer while maximizing incoming sunlight via a deep-cavity double-skin design that allows the timber of the columns to be clearly visible to the public while also integrating a dynamic shading system that allows views out. The building targets LEED Platinum certification and will be extremely energy-efficient in comparison to surrounding buildings. 

Ground-Level Public Areas 

The building’s lower levels will be open and welcoming, like a piazza, with a sophisticated, highly transparent façade that will create a lightweight boundary between the exterior and the interior. The engineering of the cable-truss façade considers the location’s high seismicity and aims to provide a safe, secure envelope. 

Rooftop Garden & City Views 

At the top, 100 meters up, a rooftop garden will provide a tranquil space where employees can relax and enjoy views of the city.

Highlights

• The building is the first example of this scale of hybrid timber structure and has undergone extensive study in relation to its fire and structural safety, with the client endeavoring to go “above and beyond” the minimum code requirements.
• The deep-cavity double skin also requires the integration of timber, which is not usually within the scope of façade contractors but seeks to make the most of prefabrication to facilitate speedy erection and protect the rest of the timber structure.
• Weathering of the timber will differ between the exposed portions and those protected behind the outer skin; one project goal is to provide the most durable treatment to the timber in all conditions.