A Study of Construction Techniques of Tibetan Villages in Saiergu Town

Traditional residential buildings of Tibetan nationality have been applauded by domestic and international architectural fields for their solid, majestic, dignified and nice features. Raw materials for construction of Tibetan buildings, such as stones, wood and mud, are all taken from nature. Construction method is original and simple hand measurement method. It is impressed by the people all around the world that a strong building that has not been moved for 100 years is built only with simple material and wall building method. At the era of rapid economic development, more and more traditional residential houses are being destroyed. Traditional construction techniques are gradually disappearing and assimilated by modern construction. In this paper, the author takes Tibetan Villages in Saiergu Town of Aba state in Si-chuan province as main research object, and explores construction techniques of residential houses of the Tibetan villages. Then, the author analyzes and collects building skills from the perspective of architecture.


Introduction
Since beginning from the second half of the 20 th century, the tide of rising urbanization has promoted the whole world pattern to change at an alarming rate.
This expansion is so short-term and rapid that it makes difficult for cities to adapt. What's more, traditional rural settlements do not have time to make a reaction, which leads to decline and wane at the same rate [1]. Traditional houses are eroded unprecedentedly. More and more experts, scholars, and professionals concerning in the field are now giving great emphasis on the return of have gradually developed into a source of regional architectural creation. As a kind of local architecture with breeding folk culture, traditional residential houses have localized "traits" and belong to "architecture without architects" [2].
However, traditional residences are fusional products on the basis of indigenous native spirit and long-term accumulation of superb craftsmanship. Site selection is an indispensable part of the folk culture of the Jiarong Tibetans. It follows the principle of "situated at the foot of a hill and beside a stream, facing to the south, and moderate terrain", adheres to the principle of "peopleoriented, people's house as home", and "productive soil and thriving crops" [3].
There are diverse ways to choose a site. Generally, it is to ask the local Aka, who is highly respected, to conduct it called "Dinglongmai". The first measurement is about mountain conditions and determines the location of houses. Then the direction of auspiciousness is measured in order to determine open direction of gates [4]. Zhai Zi mainly reflects the air defense system. Tibetan villages of Saiergu were not made in one go, with a solid foundation. It has been built for one hundred years decorated with red, yellow and white colors [5].

Building Materials
Construction characteristics of the Tibetan residential building materials are "local material for on-site construction", which have greatly reduced the construction cost of residential buildings in the economically underdeveloped mountainous areas. The building materials used in residential houses are gneiss.
Gneiss is thick with high strength, good toughness. It can withstand various loads such as shock and vibration. The stone material after mining belongs to blank material and requires different processing of thicknesses: trimming, looting, roughing, picking, cutting, polishing and special processing.
As the most primitive building material, the sand is plentiful. Based on the granularity and material composition of the sandstone, a moderately-selected building material is selected. They can be applied to bonding and jointing between the stones. Wood is used to separate space and floors. Different functional spaces are separated by wood boards, then merged into slabs with planks. Vertical traffic is done with wood.

Base
The

Structural System and Masonry for Walls
Partial pressure column serves as the load-bearing structure for the entire building. Walls are built by hand, which is prominent angular form in the corners of the wall. This technique is known as the best one for the Jiarong Tibetans. It is the load-bearing center for the entire house, equivalent to the spine of the human body. It is acclaimed as "architectural myth" by relevant experts.
The masonry of wall is generally a mortar, which means that clay mortar is required to be mixed as a binder. The gneiss is piled up. The raft and mud are sewed. The method of straightness in internal part and outward receiving is used for mansonry of walls. The thickness of walls is 0.8 meters and the top is 0.5 meters. Different forms of stone are arranged in the masonry process to form various masonry forms. However, they must be overlapped with missing gap to avoid straight seams, which ensure the strength and stability of walls.
In addition, there are some special node structures on the wall. For instance, a large square bar is used at the corners, and they are directly connected to each other to form a right angle. It is similar to modern method of spurs to ensure stability. The form of overlapping wall is only to satisfy with compression resistance, because it may be easy to collapse [7]. Workers press into large stones to stabilize the structure at a distance in the middle of the wall. Most of the gates near the gate have a humming stone. This kind of construction can be traced back to the era of horse riding. Some people put a hole stone on the wall facing the street. It is used for fastening horses and donkeys. Such structure is practical and decorative. The structure is very simple so that a tether can be tied.

Structure of Roofs, Doors and Windows
The roof beams are half-divided or herringbone-shaped on both sides, which are similar to tiny buildings with green roofs. The fir boards opened on the stand cover of fir are also known as tile plates. They are about 1 -1.5 meters long, 5 to Due to significant temperature difference between day and night, especially in the cold winter, insulation is particularly important. Limited by the structure, Open Journal of Social Sciences small rooms, thick walls and small windows of houses, it may be fully insulated and effectively resists the cold northwestern wind in winter, thereby achieving the effect of being warm in winter and cool in summer. In addition to some construction measures, some artificial measures are also adopted which are better than entering fire pits in the house. When cooking and boiling water in winter, they can provide heat through fire pits.

The Dilemma of the construction of Tibetan Villages in Saiergu Town
The construction of residential houses is rarely recorded in historical records.
The construction of residential houses is handmade craftsmanship [8]. It is also called a "craftsmanship," which relies on craftsmen. There are no actual drawings in the construction process. All of them are kept in the minds of craftsmen.
The scale of construction and other experiences are accumulated by old craftsmen for many years. Experienced construction craftsmen put their heads in a position to control the entire construction process, such as the size, progress, and quality of the house. With development of traditional Tibetan villages in Aba, it is no longer necessary to use traditional construction technique of masonry houses. The young people feel that it is useless to learn ancient skills.
Craftsmen who are involved in traditional residential houses of Tibetan villages are now very precious and face the situation that no one can succeed their skill.
Therefore, it is particularly valuable to inherit and retain the construction skills of Tibetan Village. So, the author hopes to record the construction process of Saiergu Tibetan walled houses in detail through specific words and drawings, to provide some reference for the future scientific research or construction process.

Conclusions
As an ecological local building with original feature, traditional residential houses of Tibetan villages are important carriers of regional history, Feng Shui concepts, religious awareness, folk customs, economic development, and other human geography. It is also the architecture style which reflects regional environment features of Tibetan villages in Saiergu Town.
The Tibetan villages in the Saiergu region experienced baptism of more than a hundred years or even longer, and there are still simple people living in them.
During the course of investigation, when seeing the stone house that had not been demolished was quietly and peacefully located at the foot of the big moun-