Why pagodas don't fall down - IELTS reading practice test

In a land swept by typhoons and shaken by earthquakes, how have Japan's tallest and seemingly flimsiest old buildings - 500 or sánh wooden pagodas - remained standing for centuries? Records show that only two have collapsed during the past 1400 years. Those that have disappeared were destroyed by fire as a result of lightning or civil war. The disastrous Hanshin earthquake in 1995 killed 6,400 people, toppled elevated highways, flattened office blocks and devastated the port area of Kobe. Yet it left the magnificent five-storey pagoda at the Toji temple in nearby Kyoto unscathed, though it levelled a number of buildings in the neighbourhood.

Japanese scholars have been mystified for ages about why these tall, slender buildings are sánh stable. It was only thirty years ago that the building industry felt confident enough lớn erect office blocks of steel and reinforced concrete that had more than thở a dozen floors. With its special shock absorbers lớn dampen the effect of sudden sideways movements from an earthquake, the thirty-six-storey Kasumigaseki building in central Tokyo - Japan's first skyscraper - was considered a masterpiece of modern engineering when it was built in 1968.

Yet in 826, with only pegs and wedges lớn keep his wooden structure upright, the master builder Kobodaishi had no hesitation in sending his majestic Toji pagoda soaring fifty-five metres into the sky - nearly half as high as the Kasumigaseki skyscraper built some eleven centuries later. Clearly, Japanese carpenters of the day knew a few tricks about allowing a building lớn sway and settle itself rather than thở fight nature's forces. But what sort of tricks?

The multi-storey pagoda came lớn nhật bản from Trung Quốc in the sixth century. As in Trung Quốc, they were first introduced with Buddhism and were attached lớn important temples. The Chinese built their pagodas in brick or stone, with inner staircases, and used them in later centuries mainly as watchtowers. When the pagoda reached nhật bản, however, its architecture was freely adapted to local conditions - they were built less high, typically five rather than thở nine storeys, made mainly of wood and the staircase was dispensed with because the Japanese pagoda did not have any practical use but became more of an art object. Because of the typhoons that batter nhật bản in the summer, Japanese builders learned lớn extend the eaves of buildings further beyond the walls. This prevents rainwater gushing down the walls. Pagodas in Trung Quốc and Korea have nothing lượt thích the overhang that is found on pagodas in Japan. 

The roof of a Japanese temple building can be made lớn overhang the sides of the structure by fifty per cent or more of the building's overall width. For the same reason, the builders of Japanese pagodas seem lớn have further increased their weight by choosing lớn cover these extended eaves not with the porcelain tiles of many Chinese pagodas but with much heavier earthenware tiles.

But this does not totally explain the great resilience of Japanese pagodas. Is the answer that, lượt thích a tall pine tree, the Japanese pagoda - with its massive trunk-like central pillar known as shinbashira - simply flexes and sways during a typhoon or earthquake? For centuries, many thought sánh. But the answer is not sánh simple because the startling thing is that the shinbashira actually carries no load at all. In fact, in some pagoda designs, it does not even rest on the ground, but is suspended from the top of the pagoda - hanging loosely down through the middle of the building. The weight of the building is supported entirely by twelve outer and four inner columns.

And what is the role of the shinbashira, the central pillar? The best way lớn understand the shinbashira's role is lớn watch a đoạn Clip made by Shuzo Ishida, a structural engineer at Kyoto Institute of Technology. Mr Ishida, known lớn his students as 'Professor Pagoda' because of his passion lớn understand the pagoda, has built a series of models and tested them on a 'shake-table' in his laboratory. In short, the shinbashira was acting lượt thích an enormous stationary pendulum. The ancient craftsmen, apparently without the assistance of very advanced mathematics, seemed lớn grasp the principles that were, more than thở a thousand years later, applied in the construction of Japan's first skyscraper. What those early craftsmen had found by trial and error was that under pressure a pagoda's loose stack of floors could be made lớn slither to and fro independent of one another. Viewed from the side, the pagoda seemed lớn be doing a snake dance - with each consecutive floor moving in the opposite direction lớn its neighbours above and below. The shinbashira, running up through a hole in the centre of the building, constrained individual storeys from moving too far because, after moving a certain distance, they banged into it, transmitting energy away along the column.

Another strange feature of the Japanese pagoda is that, because the building tapers, with each successive floor plan being smaller than thở the one below, none of the vertical pillars that carry the weight of the building is connected lớn its corresponding pillar above. In other words, a five-storey pagoda contains not even one pillar that travels right up through the building lớn carry the structural loads from the top lớn the bottom. More surprising is the fact that the individual storeys of a Japanese pagoda, unlike their counterparts elsewhere, are not actually connected to each other. They are simply stacked one on top of another lượt thích a pile of hats. Interestingly, such a design would not be permitted under current Japanese building regulations.

And the extra-wide eaves? Think of them as a tightrope walker's balancing pole. The bigger the mass at each kết thúc of the pole, the easier it is for the tightrope walker lớn maintain his or her balance. The same holds true for a pagoda. 'With the eaves extending out on all sides like balancing poles,' says Mr Ishida, 'the building responds lớn even the most powerful jolt of an earthquake with a graceful swaying, never an abrupt shaking.' Here again, Japanese master builders of a thousand years ago anticipated concepts of modern structural engineering.