The next step of making the Japanese bridge posts and rails has now been completed. The rails are curved and have been cut to be concentric with the curve of the main bridge support arch. They are fitted between the five bridge posts using mortise and tenon joints. The mortises were cut using a chisel mortiser machine which saved a lot of time.
After they have been painted with a timber preservative the posts and rails will be bolted to the main support arch using 10mm stainless steel bolts. These will ensure a corrosion free life from moisture and the chemicals used in the H4 treated timber used to construct the bridge.
The next step will be fitting cross members to join the two arch sections together (including the posts and rails) in readiness to fitting the floor planks. Before the are attached to the bridge, steel supports have to be made that will support the bridge at each end in concrete footings. This has more to do with keeping the weight down until the bridge has been mounted on its footings. After the concrete has cured the planks can be fitted.
Drilling square holes with the chisel mortiser.
Post and rail cutting completed
Fitting the posts and rails to one of the bridge main support arches
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.
Drilling the dowel holes using a custom made jig
View of the dowel holes prior to assembly
Clamping the dowel joints using a car jack
Japanese bridge main arch before and after shaping.
Garden armillary sphere
There is no easier way to add some style and class to a landscape than with the addition of a garden armillary
sphere. The image of an armillary sphere represented the height of wisdom and knowledge during the Renaissance and it still carries that legacy today.
An armillary sphere is a representation of the celestial sphere that was used to describe the motions of the stars and planets across the sky. The word armillary is derived from the Latin armillae meaning a bracelet. The sphere is made up of several concentric rings (or bracelets) set inside one another which collectively represent an Earth centred view of the celestial sphere.
Armillary spheres were developed by the Greeks and were used as teaching aids to help visualise the movement of stars and planets in the heavens as early as the 3rd century BCE. Larger and more precise machines were also used as observational instruments. The Chinese had also developed simple devices as early as 4th century BCE. These developed in style and complexity over the ensuing centuries culminating in the construction of the Honcheonsigye armillary in 1433. This is the only astronomical clock from the Joseon Dynasty in existence today.
The Persians and Arabs improved the device even more and developed other astronomical instruments such as the astrolabe. More refinements occurred during the Renaissance particularly by Tycho Brahe (1546-1601).
A description of the garden armillary and more photos can be found on this page.
Garden armillary sundials
Another form of garden armillary is a sundial. Usually it is simply two open rings set at right angles to each other with a rod (or gnomon) running down the central axis which casts a moving shadow along the horizontal ring section as the Sun traverses the sky. It is important to align the gnomon with the southern and northern celestial poles so that its axis will be parallel with the north/south axis of the Earth.
Below are some photos taken during construction showing the ring orientation.
Fitting the tropic rings of the armillary sphere
Aligning the meridian and horizon rings
Tin roof for hose reel
Unless you are under something like a tin roof the radiation from the summer sun causes all manner of problems. The ultra violet radiation is not only a cancer risk but also deteriorates plastic and rubber items over time. The owner of this pole mounted garden hose reel was concerned that the colour of the hose was fading and wanted a small tin roof fitted to the pole to protect the hose from the sun’s ultra-violet light.
Simple “A” frame tin roof
A simple “A” frame roof truss was made using treated pine and stainless steel screws. Being in an exposed position the frame was undercoated and painted for additional protection. Colourbond metal fencing panels which matched the existing garden shed were used to clad the tin roof. A custom made steel bracket was used to fix the tin roof to the top of the support pole.
Traditional Chinese lattice work
The Yuyuan Garden in Shanghai old town is an excellent model of classical Chinese garden architecture and has fine examples of traditional Chinese lattice. As can be seen in the photo on the right the addition of the lattice corners and overhead grills transform an otherwise barn like structure into one of considerable beauty.
With an area of over two hectares, the garden was built during the reign of the Ming Emperor Jaijing (1559) as a private garden of Pan Yunduan, an administration commissioner of Sichuan Province.
A view in the garden
The honeycombed Jade Stone Peak (Yu Ling Long) is the granite relic of Emperor Huizong (1100-26) of the Hong dynasty who procured it from Tai Hu (Lake Tai). The rough, craggy and pitted rocks carved by the currents in the lake were keenly sought after for classical Chinese garden designs to represent mountain peaks. While being transported to the Emperor, the rock was reportedly shipwrecked in the Huangpu River. There it remained until it was retrieved by Pan Yunduan and placed here across from his study. It’s peculiar shape allows water poured onto the top of the rock to spurt out from its numerous holes. It is arguably the most precious treasure in the garden.
The Jade Peak (Yu Ling Long)
More delicate lattice detail in the garden
Examples of ice ray designs
One of the more intriguing design groups described by Daniel Sheets Dye in his definitive work “A Grammar of Chinese Lattice” (1937) is ice ray lattice. Unlike most lattice designs ice ray lattice has no horizontal or vertical line elements. This makes it most effective as a grille or screen where people don’t want to feel like they are in a cage which can happen with horizontal or vertical bars.
Origins of the ice ray design
“To appreciate the designs in this division, one needs to see ice forming on quiet water on a cold night. Straight lines meet longer lines, making unique and beautiful patterns. The Chinese term this ice line, or lines formed by cracking ice; I have described it as the result of molecular strain in shrinking or breaking, but more recent observations and photographs seem to prove that it is a conventionalisation of ice-formation which has become traditional”
(Dye, “A Grammar of Chinese Lattice” 1949 pp298).
Ice forming on a pond
In his 1977 paper, “Ice-ray : A note on the generation of Chinese lattice designs” Stiny did the first analytic exercise with shape grammars which he had invented with Gips in 1976. The grammar he laid out in this paper set the standards for all shape grammars that followed. Shape grammar is beyond the scope of this blog and the reader is encouraged to further research elsewhere if so inclined. I confine myself to the aesthetic aspect of the design and its application as decorative grilles and security screens.
Ice ray design on sedan chair in Jing Hai Hall, Xidi
Small screen using the ice ray design
Circular ice ray window in the Lingering Garden, Suzhou
The ice ray lattice design is readily adapted to contemporary decor and gives a refreshing relief from vertical bars when used as a security grille. Circular ice ray designs are also interesting and can make fine features on otherwise bland walls.