• Contact us
  • Japanese

Application of Fire-Resistant Laminated Lumber, “Moen-Wood®” Column-Beam Connection Technology

—Connection method for fire-resistant wooden members ensuring fire-resistant performance, design qualities, and structural performance—

April 15, 2013Takenaka Corporation

Takenaka Corporation (President: Masahiro Miyashita) has developed connection technology (patent pending) to ensure fire-resistant performance, design qualities, and structural performance appropriate for connections between columns and beams of “Moen-Wood®,” a fire-resistant laminated lumber, and has applied this technology to build Japan’s first large fire-resistant wooden commercial facility, “Southwood” (Tsuzuki Ward of Yokohama City).

The connections of columns and beams of Moen-Wood are made using metal hardware to maintain high structural performance, but the thermal conductivity of metal is far higher than that of wood so it was feared that during a fire, the Moen-Wood itself will spread the fire. By embedding the connection hardware inside the burn stop layers, which are the mortar parts of the column and beam, Takenaka has succeeded in ensuring the structural performance and fire-resistant performance of the connection so that heat is not transmitted by the hardware. Past projects using Moen-Wood have all applied this connection method.

Moen-Wood is a trademark of Takenaka Corporation

  • Column – beam connection

    Column – beam connection

  • Moen-Wood

    Moen-Wood

To apply this method to a building project, Takenaka Research & Development Institute performed a combustion experiment with force equal to the load which will act on the building applied to a full-size column-beam connection. When it performed this experiment, Takenaka asked a third party organization to verify it from the planning stage to the results evaluation stage, confirming that it provided one-hour fire-resistant performance equal to that of Moen-Wood. The structural experiment which applied load to the connection was also performed at the Takenaka Research & Development Institute.

Outline of the technology

The technology does not require special technology, so its workability is superior, promising its wide application in the future.

1. The substitute burn layer of the column on the side to be attached to a beam is shaved off; an anchoring use hole is drilled to the load support part; and then bolts and nuts are used to anchor the T-shaped hardware.
2. A groove is cut in the load support part of the beam so the groove is perpendicular to the column, and the long side of the T-shaped hardware is inserted in the groove.
3. Drift pins are inserted so they pass through the holes drilled in the beam and the holes drilled in the long side part of the T-shaped hardware, fixing them together. Then wooden plugs are inserted from both ends of the holes so that the metal part cannot be seen from the outside.

Comparison with steel construction

Normally, in a building of steel construction, a column and a beam are connected with bolts at positions where they are visible from the outside, and the bolts, which have low resistance to heat, are protected by covering them with a fire-resistant covering. The heat-resistant covering has poor design characteristics, so generally finishing is done above it.

When this newly developed column-beam connection technology is used, drift pins are used to form the connection in order to preserve strength. The connection hardware, however, is inside the load support part where it is completely unaffected by heat inside the lumber, so a heat-resistant covering is unnecessary, achieving an external appearance with the superior design quality of wooden texture.