67-year-old Wang Jiajun is the only person in the village with a university degree. He’s a skilled architect, and also an expert on the construction theories of the Qiang village and watch tower.
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Potassium nitrate is commonly referred to as niter or saltpeter. Niter varies, according to the amount of potassium nitrate it contains, but the proportion is usually less than 10%. So the loess in Taoping Qiang Village, which contains 20% potassium nitrate, is very rare. It’s used in construction because of its outstanding ability to resist light, heat and corrosion.
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Good nitre, if placed on burning charcoal, will sparkle.
Wang Jiajun picks up a handful of nitre from the wall and lights it with burning ash. The niter really sparkles.
The experiment shows how rich in potassium nitrate the rubble and loess here are.
Potassium nitrate is high-tensile and a powerful coagulant. Its use as a building material has been a key factor in the Taoping ancient Qiang Village’s survival of 2,000 years of earthquakes.
So Qiang people use the locally-available rubble and loess as their construction materials.
Qiang people long ago became experienced in mitigating the effects of earthquakes. The techniques they developed are an intangible cultural heritage, which they incorporated into the construction of the ancient village.
Construction starts with digging the foundation, which can be square, hexagonal or octagonal, and must be three or four meters deep. The foundation must stand on bare rock. The foundation stones are large pieces of rubble.
In the wall, the pieces of rubble fit one another naturally. Evidently, there is nothing random abut this arrangement.
The builders first select good quality rubble and hammer the irregular pieces to get rid of any fragments. They then put the various pieces into place, adjusting their positions constantly so as to maximize the cohesion between rubble and loess. The adjustment can be repeated anything up to fifty times.
Experienced engineers made precise calculations concerning the bases of the walls and the walls themselves. Every piece of rubble and every handful of loess was carefully placed, the first layer lengthways and the second, sideways, so as to maximize the cohesion. Both sides of the walls had to be properly arranged, centred on large stones in the middle.
To increase the shock resistance of the walls, the Qiang craftsmen made them all slightly concave. They also formed a corner on every wall, known as the “wall stud” or “Qianlengzi” in the Qiang language. Wall studs placed at the edge of the houses would bear the full force of any earthquake, and would allow the Qiang houses to withstand both transverse and vertical shocks.
It was the practice, after each storey of a building was completed, for nothing to be built on top for at least a year. The Qiang people did this to allow the rubble and loess to settle, and bond more strongly. A wall would be deemed sufficiently stable only if it could withstand the climate changes and rainstorms of a whole year, without losing any of its loess.
So it took three years to build a three-storey Qiang building and thirteen years to build a thirteen-storey one.
The rubble and loess walls, built over 2,000 years ago, may look delicate. But they are in fact extremely solid.
To improve their resistance to earthquakes, Qiang houses were built in a pyramid structure, characterized by a wide bottom and a narrow top. The walls in the bottom layer are 60 cm wide, and those in the top layer, 20 to 30 cm wide. The entire wall leans inwards, towards the middle.
In a five-storey building, there could be a horizontal difference exceeding 20 centimetres between the top and bottom walls. The walls, being solidly built and symmetrical, are capable of withstanding a force from any direction.
Besides the solid walls, Qiang buildings incorporate other, supplementary support. Three wooden pillars form a system that supports the floors and the roof.
Qiang buildings are usually quite low. Those used for living and working tend to have just three storeys. The inner structure adopts the “space cutting” technique combining stone walls and beams. The layers of wall are separated every “zhang” by beams, 20 centimetres in diameter with rafters above them.
A smooth groove was cut in the top of the wooden pillar on the first floor, and another in the corresponding part on the bottom of the wooden pillar for the second floor. The main beam would be inserted between them. Sometimes a supplementary beam might be added, parallel with the main beam. This was in a fact a primitive form of a bucket arch, which could disperse the pressure from the junction of the wooden pillars and beams so as to strengthen the beams.
The interweaving of the beams and stone walls, combined with the joining of the beams and wooden pillars, effectively reinforced the whole structure and increased its capacity to withstand shocks.
Seen from above, the ancient Qiang village is revealed as a collection of buildings all forming a complete architectural complex.
The various houses are linked to one another in an integrated whole. The buildings and alleys, by being connected, can better withstand earthquakes.
Compared with the interconnected ancient Qiang houses, later Qiang buildings are more independent, in order to accommodate tourists. However, being independent makes the buildings more vulnerable to earthquakes.
The ancient Qiang people acquired their architectural genius by studying Nature. Having migrated from far away, they have now been living in this place for many generations. To visit Taoping ancient Qiang Village is like traveling back through the long history of the Qiang people.
It was raining on July the 15th, 2008. The Qiang people, still getting over the shock and devastation of the Wenchuan earthquake, were gathering beside the village entrance, dressed in their finest.
What were they waiting for?
“I hereby launch the project to save and protect the watchtowers and villages of the Qiang Nationality!” With these words from Shan Jixiang, director of the State Administration of Cultural Heritage, the Qiang started to sing and dance, celebrating the preservation of their unique heritage.
Guided by such principles, the Qiang village is promised an even better appearance in the future.
Today Taoping ancient Qiang Village is much more than a remarkable collection of buildings. In a sense, the Qiang houses and watch towers have assumed a historical mission: to keep alive a unique architectural culture. Architecture in its highest form incorporates into buildings mankind’s respect for life, and lays a solid foundation for the survival of human beings in their rapidly-changing environment.
Editor:Yang
