K. K. Arakawa Zaimokuten Zohsaku Kohjou Jimusho
(Office Building of the Arakawa Lumber Company – Nakoso Plant)

This particular structure was built within the Iwaki Wood Processing Cooperative facility grounds near the Nakoso Interchange on the Johban Highway.
The structure was designed and constructed as an example of Timber Frame Structures with Wide Open Spans that is possible with Sugi Timbers that make up approximately 80% of the forest lands of Fukushima Prefecture.
JAS Certified Large Cross Section Sugi Timbers are utilized for the Upright Posts and Horizontal Beams along with the Pierced Column Shear Wall system to create large open spans that offers great design flexibilities.

The Large Cross Section Sugi Timbers used in the structure are the first commercial application of JAS Certified Large Cross Section Sugi Timbers produced at the Iwaki Wood Processing Cooperative facility upon securing JAS Certification in March 2013.

With the application of the High Performance Shear Walls developed and Certified in January 2014 (equivalent to Wall Multiplier 8 to 10), 90% of the exterior wall surface was possible to be left open.
A total of 15 High Performance Shear Walls were employed on the 1st and 2nd floors for a total of 30. The Shear Walls Sections were fabricated at Daitec K.K.’s manufacturing facility, transported to the site and installed in place during the Framing stage.
The total framing time was reduced significantly.

Through the strategic placement of 240mm x 600mm x 7,200mm Built-Up Beams under the 2nd Floor level and 240mm x 380mm See-through Built-Up Beams on the Roof Level, clear open spaces measuring 7.2m x 7.2m was made possible.
The combination of High Performance Shear Wall system and Long Length Built-Up Beams based on JAS Certified Large Cross Section Sugi Timbers, make designing relatively large open spaces commonly desired in large commercial structures.

By enveloping the exterior of the structure with non-structural “Glazed Curtain Walls”, the structural Timber Frame is left exposed which facilitates the adjustment of the Wood Dowels and Wedges as the Timbers shrink with time and greatly facilitates the maintenance and improves the durability of the structure

© 2015 K.K. Daitec.