The ancient buildings and temples of Kathmandu Valley are fairly earthquake resistant. In most cases, possible precautionary measures had probably been taken in the planning, design and construction of these buildings. This is especially true for the construction of temples. Most of the important temples including Pashupatinath and Nyatapola have survived several high intensity earthquakes. The following characteristics of the old buildings could be considered to be their strengths, although some might be incidental or due to lack of modernity:
1. Floor to floor height is generally kept low.
2. Timber posts are used for vertical members
3. Continuous timber lintels over all types of openings are generally found.
4. The size of the openings is generally limited with enough distance between the openings.
5. Even when mortar used had to be of mud, fibrous and cementing materials are used.
6. The design is generally compact with all members tied together.
7. The location and orientation of the buildings and roads were also carefully thought out.
8. Height is generally restricted depending on the materials used.
9. Lighter roofing materials are used.
Just after the 1990 BS earthquake, the precautions advised to be taken in building construction show the wealth and depth of the knowledge that that generation had on earthquake resistant buildings. These include:
• Strong foundation, depth according to the soil properties and width as wide as possible to spread the effect of the earthquake.
• Brick should be of good quality and preferably polished.
• All parts of the construction should be well bonded. There should be no isolated/ detached parts.
• Openings should be limited. The distance between the openings should be enough.
• No false decorative elements with projections or cantilevers should be allowed.
• Iron beams in cement construction are preferred structural elements.
• Lime surkhi walls are also fairly strong. This may be more economical as less bricks will be required.
• Timber columns are preferred to brick ones.
• The corners of the walls must be bonded and tied. Arches must always be avoided. Lintels over openings should be preferably continuous.
• Floor to floor height should be limited. The total height allowed should depend upon the materials and methods used. For mud construction it should be much less; lesser the height better.
• Roofing should be as light as possible. Those who cannot afford c.g.i. sheets can use tins painted with kerosene.
• Reinforced concrete and cement are good materials.
• Masonry in lime surkhi and lintels over openings should be preferred.
• Buildings with mud mortar should not be tall.
• The poor should construct their houses with light roofing and compact design.