性欲雅思经典阅读及题解Why pagodas don’t fall down

2021年1月21日发(作者：apologize是什么意思)
Why pagodas don’t fall down

In a land swept by typhoons and shaken by earthquakes, how have Japan's tallest and seemingly flimsiest old buildings - 500
or so 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 so stable. It was only thirty years
ago that the building industry felt confident enough to erect office blocks of steel and reinforced concrete that had more than a
dozen
floors.
With
its
special
shock
absorbers
to
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
to
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
to sway and settle itself rather than fight nature's forces. But what sort of tricks?


The
multi-storey
pagoda
came
to
Japan
from
China
in
the
sixth
century.
As
in
China,
they
were
first
introduced
with
Buddhism and were attached to 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 Japan, however, its architecture was freely adapted
to local conditions - they were built less high, typically five rather than 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 Japan in the summer, Japanese builders learned to extend the eaves of buildings further beyond the walls.
This prevents rainwater gushing down the walls. Pagodas in China and Korea have nothing like the overhang that is found on
pagodas in Japan.


The roof of a Japanese temple building can be made to 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 to have further increased their weight by
choosing to 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,
like
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 so. But the answer is not so 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 to understand the shinbashira's role is to watch a
video
made
by
Shuzo
Ishida,
a
structural
engineer
at
Kyoto
Institute
of
Technology.
Mr
Ishida,
known
to
his
students
as
'Professor Pagoda' because of his passion to 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
like
an
enormous
stationary
pendulum.
The
ancient
craftsmen,
apparently without the assistance of very advanced mathematics, seemed to grasp the principles that were, more than 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 to slither to and fro independent of one another. Viewed from
the
side,
the
pagoda
seemed
to
be
doing
a
snake
dance
-
with
each
consecutive
floor
moving
in
the
opposite
direction
to
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