1998 - Redevelopment of Chi Lin Nunnery

The timber structures in the project are designed to have a service life of 500 years. Its structure and construction, in each single step and detail, are to relive the ancient Tang dynasty modus coupling with modern technology and philosophy. The specified ancient features include :

• The “Ze-jiao” columns which slant inwardly (as the legs of a chair) as opposed to absolute verticality.
• The “Sheng-qi” column disposition by progressive increase in length towards interior, thereby focusing the balance of the system towards the centre.
• The “tou-kung” system which dates back to about 500BC is a built-up timber bracket cluster to support the cantilevered eaves and transfer the load to the columns. Each bracket set is an interlocking layered assembly of three-dimensional timber elements of bearing block, bracket arm, slanted lever arm, small beam and beam head.
• High water resistant tree barks placed under roof tiles for a service free water-proofing system.

The timber building has to cater for the local environmental conditions for its longevity. The humidity, temperature and rainfall characters of Hong Kong are disposed for insect attack. In summer, the buildings are to withstand severe typhoons. In dry winter, fire protection poses the major concern. Available tools were deployed to meet the demanding standard, including :

• Finite element analysis of the intricate load-transferring bracket systems to verify the structural viability, performance and geometric proportion of the ancient designs which were previously dominated by experience, family heritage and abacus
• Introducing stainless steel pins concealed in the “tou-kung” system as stability enhancement and anti-typhoon devices
• Built-in steel wind frames
• Implementing fire engineering approach and active provisions to ascertain fire safety
• Analysis of meteorological history to assess the equilibrium moisture content for timber design
• Tubes filled with chlorine based insect repellent embedded underground to prevent white ant attack
• Detailed measurement of each component for preliminary computer mock-up study and record before shipment for erection
• laser-cutting of timber elements

The selection of material, design, fabrication and installation procedures were all meticulously studied according to the properties and available quantity of the timber. Chinese Pierre Dacrydium, Madhuca JF Geml, Hainanensis Merr, Canadian Doussie and African Yellow Cedar were selected as the main sources for various parts. The timbers were procured from the respective source countries, seasoned in Japan, fabricated in China and assembled in Hong Kong. Totally 15,000 m3 of timber was used.

The roof is topped with over 238,000 pieces of ‘smoked-baked’ tiles anchored to the purlins with acid-free galvanized copper wiring against uplifting wind force.

The project was completed in 1998.

Please click to enlarge the photos