ABC Trading Head Office

The project site is adjacent to Hie Shrine, Sotobori avenue, and a public open space, and it embraces a rich environment despite its location in the central district of Nagata-cho, Tokyo. The scope was to bring in as much nature as possible while solving the problems of segmented working spaces and level difference in the former headquarter office, and acquiring seismic resistance and BCP suitable for the headquarter office. A special glass with high thermal performance was used on three sides of the façade excluding the west side, which faces the neighboring building, to achieve both openness and external load control. The façade of the 2nd and 3rd-floor levels is set back for an outside terrace space that takes in nature from the surroundings. The offices on and above the 4th floor are planned to acquire a wide and uniform workspace by maximizing the floor area and organizing a compact building core at the west side of the building. The atrium and the open stairs adjacent to the workspaces could be accessed from all levels, which convey the presence of working employees and atmosphere surrounding their workspace, and thus expressing the office’s “transparency.” Ideas such as the application of floor radiant air conditioning system for the comfortable working environment of the in-house employees, natural ventilation utilizing the staircase, high-performance glass, and task-ambient lighting fixtures allowed us to obtain a BEI value of 0.5 and BELS☆5, realizing the next generation of the energy-efficient office building that reduces environmental loads. A 100-ton seismic-tuned TMD (Tuned Mass Damper) equivalent to 4% of the dead load is placed on the rooftop, which reduces the duration of lingering shaking right after the mainshock to half. Instead of dispersedly locating dampers on each floor, they are centralized on the rooftop so as to function as a “compact vibration damping for mid-sized steel structure” that improves the seismic resisting performance while allowing more flexibility for the workspaces. Most office spaces are finished without suspended ceilings to prevent the collapse of ceilings and equipment in case of earthquake; this was enabled by the “method of omitting transverse stiffener in steel girder,” which eliminates the beams and deck plate with truss rebars. Furthermore, workspaces such as executives’ floor and large meeting rooms are planned to accommodate three-day continuous operation during potential threats. Through repeated discussions on its distinctive working style, and by applying its merchandise to key locations such as wood flooring around the office perimeter, a unique office space tailored for ABC Trading is realized.