Japanese Bridge Main Arch

 

Main arch

Main arch sections before assembly


The Japanese bridge main arch was the trickiest item to build. It was important to have the timber grain following the curve of the main arch as closely as possible to ensure a strong structure. This was achieved by dividing the arch into five sections, joining them with dowels and then cutting the final curve.

By using this method the weight of the bridge will be spread across the angled sections of the arch and, with the addition of an aluminium band secured under the arch section with stainless steel screws, ensures a very strong support for the final structure.

Each section of the Japanese bridge main arch was joined together using five 13mm Tasmanian Oak dowels. A special jig was made (see photo below) to ensure the correct alignment of the holes prior to assembly. Due to the length of the arch (over three metres) the joining process was done one section at a time. A car jack was used to clamp each joint together while the glue dried.

Now that the Japanese bridge main arch sections are finished work will start on cutting the curved handrails and supporting posts. This will be the subject of another post.

Dowel drilling jig

Drilling the dowel holes using a custom made jig

Dowel holes ready for dowels

View of the dowel holes prior to assembly

Clamping the dowel joints

Clamping the dowel joints using a car jack

Completed Japanese bridge main arch

Japanese bridge main arch before and after shaping.

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