Root bridges

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for engineers in KPU(Kabul Polytechnic University)
A.J.NIAZI

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Root bridges

  1. 1. ‫ﺁﻳﺎ ﻣﻬﻨﺪﺳﯽ ﺗﻨﻬﺎ در ﺳﺎﺧﺘﻤﺎن ﺑﺎ ﻣﻮاد ﮔﻞ و ﺧﺸﺖ و ﮐﺎﻧﮑﺮﻳﺖ اﺳﺖ؟‬ ‫روﻳﺎﻧﺪن ﭘﻞهﺎﻳﯽ زﻧﺪﻩ‬ ‫هﻨﺪ، اﺳﺘﺎﻧﯽ دارد ﺑﻪ ﻧﺎم ﻣﮕﺎﻻﻳﺎ ‪ .Meghalaya‬ﮔﻤﺎن ﻣﯽرود ﮐﻪ اﻳﻨﺠﺎ ﻳﮑﯽ از ﭘﺮ ﺑﺎرانﺗﺮﻳﻦ ﻣﻨﺎﻃﻖ دﻧﻴﺎ ﺑﺎﺷﺪ. در اﻳﻦ‬ ‫ﻣﻨﻄﻘﻪ ﺟﻨﮕﻞهﺎﻳﯽ اﻧﺒﻮﻩ و رودهﺎﯼ ﺧﺮوﺷﺎن ﺑﯽﺷﻤﺎر ﻗﺮار دارد.‬‫ﮔﺬر از اﻳﻦ رودهﺎ ﻳﮑﯽ از دﻏﺪﻏﻪهﺎﯼ هﻤﻴﺸﮕﯽ ﻣﺮدم ﺑﻮدﻩ اﺳﺖ. اﻣﺎ ﻣﺮدم اﻳﻦ ﻧﺎﺣﻴﻪ ﺑﻪ ﺟﺎﯼ ﺑﻨﺎ ﮐﺮدن ﭘﻞهﺎﻳﯽ از ﭼﻮب،‬‫ﺳﻨﮓ، ﻓﻠﺰ ﻳﺎ ﺳﻴﻤﺎن و ﺑﺘﻦ و ﺑﻪ ﺟﺎﯼ اﺳﺘﻔﺎدﻩ از داﻧﺶ ﻣﻬﻨﺪﺳﯽ و ﻣﻌﻤﺎرﯼ ﭘﻞ، ﺳﺎلهﺎﯼ ﻣﺘﻤﺎدﯼ اﺳﺖ ﮐﻪ ﺁراﺳﺘﻪ ﺑﻪ هﻨﺮ و‬ ‫داﻧﺸﯽ ﻣﻨﺤﺼﺮ ﺑﻪ ﻓﺮد ﺷﺪﻩاﻧﺪ!‬ ‫ﺁﻧﻬﺎ ﭘﻞهﺎ را ﻧﻤﯽﺳﺎزﻧﺪ، ﺑﻠﮑﻪ ﻣﯽروﻳﺎﻧﻨﺪ!‬‫ﻣﺮدم رﻳﺸﻪهﺎ و ﺷﺎﺧﻪهﺎﯼ درﺧﺘﺎﻧﯽ را ﮐﻪ در دو ﺳﻮﯼ رودﺧﺎﻧﻪ ﻗﺮار دارﻧﺪ، ﺑﺎ دﺳﺖ در راﺳﺘﺎﯼ اﻓﻘﯽ ﻗﺮار ﻣﯽدهﻨﺪ و ﺑﻪ‬ ‫ﺗﺪرﻳﺢ ﺷﺒﮑﻪاﯼ زﻧﺪﻩ از رﻳﺸﻪهﺎ و ﺷﺎﺧﻪهﺎ اﻳﺠﺎد ﻣﯽﮐﻨﻨﺪ.‬ ‫ﻃﻮل ﺑﻌﻀﯽ از اﻳﻦ ﭘﻞهﺎﯼ زﻧﺪﻩ ﺑﻪ ﺣﺪود ﺳﯽ ﻣﺘﺮ هﻢ ﻣﯽرﺳﺪ و ﻣﯽﺗﻮاﻧﺪ وزن ﭘﻨﺠﺎﻩ ﻧﻔﺮ و ﺣﺘﯽ ﺑﻴﺸﺘﺮ را هﻢ ﺗﺤﻤﻞ ﮐﻨﺪ.‬
  2. 2. ‫از ﺁﻧﺠﺎ ﮐﻪ اﻳﻦ ﭘﻞهﺎ زﻧﺪﻩ هﺴﺘﻨﺪ، ﻣﻘﺎوﻣﺖ و دوان ﺁﻧﻬﺎ ﻧﺴﺒﺖ ﺑﻪ ﭘﻞهﺎﯼ ﭼﻮﺑﯽ، ﺑﺴﻴﺎر ﺑﻴﺸﺘﺮ اﺳﺖ. از ﺁﻧﺠﺎ ﮐﻪ ﻣﻴﺰان ﺑﺎرش‬ ‫ﺳﺎﻻﻧﻪ در اﻳﻦ ﻣﻨﻄﻘﻪ از هﻨﺪ، ۵١ ﻣﺘﺮ اﺳﺖ، اﻳﻦ ﭘﻞهﺎﯼ زﻧﺪﻩ ﺑﻪ ﺗﺪرﻳﺞ رﺷﺪ ﻣﯽﮐﻨﻨﺪ و ﺑﺮ ﻣﻘﺎوﻣﺖ ﺁﻧﻬﺎ اﻓﺰودﻩ ﻣﯽﺷﻮد.‬
  3. 3. How to grow your own bridge: Villagers create living crossings bytraining roots across a riverDeep in the rainforests of the Indian state of Meghalaya, bridges are not built,they’re grown.Ancient vines and roots of trees stretch horizontally across rivers and streams,creating a solid latticework structure strong enough to be used as a bridge.Since the area receives around 15 metres of rain every year, a normal woodenbridge would quickly rot. But because the growing bridges are alive and stillgrowing, they actually gain strength over time. For more than 500 years localshave guided roots and vines from the native Ficus Elastica (rubber tree) acrossrivers, using hollowed out trees to create root guidance systems. When they rootsand vines reach the opposite bank they are allowed to take root. In time, a sturdyliving bridge is produced. Some can take ten to fifteen years to become fullyfunctional.Read more: http://www.dailymail.co.uk/news/article-2035520/Meghalaya-villagers-create-living-bridges-training-roots-river.html#ixzz1bfwJVohy accessed:24 October 2011

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