21/01/2017

英国论文代写:伦敦千禧旅桥结构研究

英国论文代写:伦敦千禧旅桥结构研究

伦敦千禧旅桥于2000首次启用。这是座桥,成千上万的人成群结队地走过。这是吊桥,所以这座桥有些摇晃的机会。虽然这座桥一开始穿过这座桥,但并没有造成伤害,预期效果开始显现。人们被同步他们的脚步与导致抖动越来越多的桥梁运动(AASHTO,1991)。

之所以发生这种情况,是因为桥上有微小的晃动,过桥的人们开始通过改变他们的运动模式来协调这一摆动.。然而,不是减少运动,人们造成反馈回路。在这种情况下,人们更多地试图停止运动,抖动发生更多。人们在这个移动甲板上施加的侧向力被发现在桥上移动.。

这种摆动导致了桥上的共振和振动.。这也发现,这种现象在这座桥是不是因为技术问题,但这种现象可以观察到任何地方,如果横向频率低于1.3 GHz和加载足够数量的人一次。这是一个钢结构失败的时候,由于这座桥的动作,行人是相当高的桥梁突然。

桥梁结构为浅悬索桥。在这种情况下,桥梁电缆尽可能低于桥面的水平。这种结构比传统的悬索桥结构浅。装配式钢箱用作桥梁的横臂。电缆是桥梁的一次结构的来源。这些电缆的轮廓非常浅。这座桥遵循带状桥的一些特点,但这座桥有多个跨度.。由此产生的总恒载索力是22.5mn。该桥结构体系处于水平和垂直方向。

英国论文代写:伦敦千禧旅桥结构研究

The millennium Brigade Bridge at London was first opened in 2000. This was Foot Bridge so thousands of people flocked to walk across it.  This was suspension bridge so there are chances of some wobble in this bridge. Though this bridge did not cause harm as soon as people started to cross through this bridge, an expected effect began to emerge. The people were synchronizing their footsteps with the bridge movement which caused it wobble more and more (AASHTO, 1991).

This happened because with the small wobble in the bridge, the people who were crossing the bridge started to counterpart this wobble by changing their patterns of movement. However, instead of reducing the motion, the people were causing a feedback loop. In this case, the people as more tried to stop the motion, the wobble happened more. The lateral force exerted by people on this moving deck was found as the movement over the bridge.

This wobble led to resonance and vibration on the bridge. This was also found that this kind of phenomena on this bridge was not because of the technical issue but this kind of phenomena can be observed anywhere if the lateral frequency is below 1.3 GHz and loaded with sufficient number of people at a time. This was a steel structure failure for this bridge at the time because of the movements form the pedestrians was quite high for the bridge suddenly.

The bridge structure was shallow suspension bridge. In this case the bridge cables are as much as possible below the level of the bridge deck. This structure was shallower than the conventional suspension bridge structure.  Fabricated steel box are used as transverse arms for the bridge. The cables are source of primary structure of the bridge.  These cables have very shallow profile. This bridge follows some of the characteristics of the Ribbon Bridges but this bridge has multiple spans. The resulting total dead load cable tension is 22.5MN. The structural system of this bridge is in both horizontal and vertical direction.

 

 

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