Реферат: Technology Essay Research Paper On November 7

Technology Essay, Research Paper

On November 7, 1940 the Tacoma Narrows Bridge was hit by winds of up to

40mph. The bridge began to twist and flutter. Some cables snapped and a

six-hundred foot section of the bridge fell into Puget Sound. ^Wind is

but one disaster, earthquakes are another^ (Jay Stuller 36). Disasters

like this one and others could have been avoided if the proper

precautions had been taken. Due to the disasters in the world the

structures of today and tomorrow are much safer. Today most of these

catastrophes are avoided because of the up to date technology, like

architecture, predicting the disasters before hand and new techniques

used by emergency rescue teams. Some major advances in today^s

buildings include such things like the material used. For instance

products like steel-reinforced concrete (refer to diagram 3-1), steel

framing, and properly braced wood frames for houses are a few examples

of how buildings are being retrofitted and new buildings are being

built towards protection from disasters. As well, the foundations of

the buildings can be built on shock absorbing ^base isolators^

containing springs or alternating layers of steel plates and rubber, to

counteract the effects of earthquakes.

In Japan architectures have been keeping mind earthquakes while

designing and building structures. Unfortunately the buildings were

mainly designed to withstand a vertical force. The Japanese buildings

were designed to withstand a certain acceleration force, but in January

1995, an earthquake hit the city Kobe devastating the buildings, which

were thought to be safe. It just shows, ^that building design criteria

are crucial to withstanding effects of earthquakes^ (Gerad Baker 12).

The normal Japanese wooden houses that had heavy roofs collapsed, and

also newer homes were demolished, as seen on diagram 3-2. This could

have been avoided by building the houses with lighter plywood frames

with crossbars that distribute force evenly rather than houses with

heavy timber walls that collapse under force. As well the materials

used to build the structures has a great deal to do with the survival

rate of buildings. The use of reinforced concrete is thought to be a

major reason why buildings stay intact. It is possible to reinforce

older buildings with extra concrete simply and effectively, which has

been done in California since 1989. Bridges, a totally different

aspect of building, but a very similar method for creating sound

structures. During the Kobe earthquake the Hanshin expressway collapsed

on its side for a stretch of 600m (pictures seen on page 5). This type

of roadway is built upon reinforced concrete pillars. There is steel

inside the pillars to increase its ability to bend and flex with the

quake. But unfortunately, this creates new problems; shaking the road

from side to side, the concrete crumbles because it is confined and

under a great force, the concrete will split and give way. To deal with

these problems builders can fit metal jackets to limit any extra force

by containment, inserting steel spirals or fitting steel rings, where

force is taken into the steel. Another famous bridge, the Golden Gate

Bridge, in San Francisco went under a $147 million earthquake-proofing

retrofit after the 1989 Loma Prieta earthquake. The main parts

reconstructed were to the towers, supporting piers and the approaches

to the bridge. The Bridge was reinforced at the anchorage housings, and

fit with vibration-dampening additions over the south bridge. While the

north viaduct gets ^isolators^, to stop ground movement and shake

entire structure.

The Beaches of the world all seem to be receding. In the United States

about 90% of the coast is eroding. The reason for this is because of

constant storms and the removal of natural buffers (sand dunes) by

humans to build hotels and homes. Although the sand is replaced

constantly, ^most comes back, you don^t get back all you lost^ (Betty

Nash). There are several thoughts on how to stop or reduce erosion

damage that includes both hard and soft structures. The hard concrete

structures should be placed parallel or perpendicular to the shore to

confine the sand to a certain area. But haplessly, this solution can

create more problems because although it may protect one area it can

accelerate erosion in adjacent areas. The soft idea is to ^nourish^ the

beaches with similar sand. Now although, the method can work it can be

very costly. The decision is up to the owners of the beach, whether or

not the cost damage is greater than the cost of keeping it nourished.

In Virginia Bea! ch it saved an estimated $12. 5 million (1993 U.S.

dollars) in damages. So in spite of the fact that technology has

advanced it is still not equal to the power of Mother Nature. Humans

have been able to counteract some damages with new ideas like

reinforced concrete, building designs, safety measures, and use of

previous disaster information to reduce the risk of human causalities.

For the rest of time Man will battle nature, one always trying to top

the other.


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