Maple Bridge at the Japanese Friendship Garden in Balboa Park, San Diego, CA

by David Sipos (adapted from The Wooden Post, vol 11, June 2018)
Originally published in the newsletter of The Japanese Friendship Garden Society of San Diego, Vol 25, Issue 1 in Jan/Feb 2015

The San Diego Japanese Friendship Garden had extended its grounds and now occupies much of the gulch below the original garden which was built in 1915. The extensive expansion allowed several structures to be built including 3 bridges in different styles curved, viewing deck and a zig-zag. Minka-Woodworks Inc. was chosen to furnish the bridges over the course of 5 years. The Maple bridge was the first one to be manufactured and installed.

A feature to look forward to in the canyon is the new Maple Bridge which will provide a beautiful vantage point of both the pavilion and the waterfall stream. Maple Bridge, or Momiji Bashi, represents the natural landscape of the canyon setting throughout the seasons. The variety of maples including the red maple, green maple, native maple, etc. are planted around the bridge and will show brilliant fall colors. The 14’ long bridge with a 64’ radius arc is made of recycled Alaskan Yellow Cedar timbers from the railroad trusses of Idaho. The material is one of only three known North American species that is dry rot, fungus and termite resistant.

The bridge was designed by the late Takeo Uesugi from Takeo Uesugi and Associates in West Covina, CA. The Maple Bridge uses traditional Japanese joinery – mortise and tenon with a reinforcing pin at the handrail in between the posts and sliding dovetail, which connects the base of the posts to the arched beams that cross over the stream. The bridge was manufactured by David Sipos, Minka-Woodworks Inc., at his Ojai, CA shop and assembled at the Garden. The planning, careful selection of materials and construction of this bridge took three months using traditional Japanese hand-tools. Every piece above the decking was manufactured out of solid timbers. The handrail was cut out from two 8” x 10″ x 14’ long timbers. The decking is Kayu-Batu from Indonesia. The final finish was achieved using the Japanese handmade plane or “kanna” that creates a water repellent surface. Like the Garden itself, the bridge will naturally age and change color reflecting its own seasonal beauty that can be appreciated over time for many decades.

The base structure is 2” x 4” x 16” laminated Alaskan yellow cedar. Uprights are recycled Alaskan yellow cedar with traditional mortise and tenon joinery for the horizontal pieces and connecting them to the handrail. Above center, the sliding dovetail joint (test piece) to connect the upright posts and the curved beams. In order to comply with CA building codes the support structure was anchored to a concrete foundation with threaded rods. The posts were secured with timber locks.