■100meter Tall Titanium Tower

Art Tower Mito is a comprehensive cultural facility symbolized by the 100meter tall titanium tower that opened in 1990 to commemorate the 100^th anniversary of Mito as an official city.
The titanium tower is composed of 28 contiguous tetrahedrons (triangular pyramids) placed on top of each other, each set at a different angle.
Kikukawa participated in the metal construction of this monumental project.

■The First Titanium

The material (titanium) chosen for the façade of this tower captures the architect’s vision to ‘choose high-quality materials to build architecture that last’.
Titanium is known as a maintenance-free material for its high resistance to corrosion and weathering. It is 60% lighter in weight than steel and is superior to other metals in strength and workability.
Despite such superior properties, the usage of titanium is limited in architecture for its high material cost. This project pioneered the use of titanium on a large scale within Japan: consequently, it was also Kikukawa’s first attempt to implement titanium panels on such a large scale.
Regardless of these conditions, Kikukawa was able to provide high-quality titanium panels by collaborating closely with the metal sheet provider and repeated experimentations.

■9.6meter Titanium Equilateral Triangles

The titanium tetrahedrons composing this tower is formed with 57 units of equilateral triangles with 9.6m sides. Each triangle is formed with 8 pieces of 1.5mm thick hairline finished titanium of roughly 1050mm width ranging in length and shapes from trapezoids to triangles.
The corners where the panels meet the structural truss are joint by 1.5mm stainless steel cut in φ95mm half circle. The backing frames are composed of bent 1.5mm stainless steel assembled into a unit.
To ensure the integrity, wind resistibility, and water sealing, the panels and frames were carefully designed and calculated. This is evident in details such as the 230mm risers at the edge of the panel.

■Stainless Steel Round Fittings And Louvres

The observation floor at 86meter high has 70 circular windows of φ432mm and φ670mm. The window system has excellent airtightness and is equipped with an opening/closing mechanism.
The cross-section of the window reveals that the glass window is placed between the interior and exterior fittings. The 120mm thick exterior fittings are tapered, and the interior fittings are 280mm thick cylinders, both assembled into a unit within our factory.
Other triangular sides of this tower are equipped with a single line of φ432mm circular windows.
The titanium triangles at the foot of the tower are equipped with louvers towards the bottom. These louvers are formed by hairline finished 1.0mm thick stainless steel bent into a Z shape.

Assembling the titanium panels for Art Tower Mito

■Installing Large Panels Sky-High

The 9.6meter assembled equilateral triangular panels are roughly 1ton in weight. Thus, their transportation and installation required consideration from the detailed design stage.
Frames and hardware for transportation, ground assembly and suspension were designed and fabricated, as well as a system to pull in the lifted panels to the structural truss.
The actual installation was achieved by equipping the panels with bespoke hinges so that they could be pulled and adjusted into place with bespoke rod-shaped installation hardware.

■A Symbol of Mito

It was a true pleasure for Kikukawa to participate in this monumental project. Art Tower Mito is now known by many as the symbol of Mito City, and it is also one of the most well-known works of the Pritzker Award-winning architect, Arata Isozaki.
This was a cutting-edge project in its design, large-scale usage of titanium and its implementation. It is projects like these that challenge our expertise and hone our metal-crafting technology which expands our ability to provide comprehensive solutions for a variety of architectural projects.