Study and Analysis of Well Foundation and Pile Foundation for Minor Bridges over Small River
Since time immemorial, mankind has been using various techniques to cross the rivers, streams or any depression without closing or obstructing the original flow through a structure called bridge. With the span of time and advancements in civil engineering, several types of bridges have come into existence like wooden, steel, masonry arches, RCC and prestressed concrete bridges. Indian Roads Congress categorizes three types of the bridges on the basis of length i.e. culverts up to 6.0 m, minor bridges above 6.0 m to maximum 60.0 m length and major bridges above 60.0 m. In present scenario, minor bridges over small rivers has become necessary for development and prosperity of nation as most of the roads have to cross small rivers at several places to connect remotest corner of the country.
Bridges, though a man made structure, over a period of time become an important part of environment because in most of the cases water flowing below is used for drinking, irrigation and underground recharging. The alluvial region of India spread from Punjab to West Bengal has a peculiar nature because soil is almost soft in nature consisting of mainly sand, clay and silt which is fertile for vegetation. Water retention and its movement condition are high throughout the year. Several type of water bodies which exists in this type of region are pond, small drain, small and medium rivers which drains into the big rivers like Ganga, Yamuna, Ghahgra, Gomti and Sai etc.Since long time, road system on the earthen track and pucca has been introduced for traffic like chart, chariot and motorised vehicle. There were little number of bridges over major rivers i.e. bridge alone to cross over the river Ganga except in few places like Allahabad, Kanpur and Varanasi and over the Ghaghra Algine bridge, Maghighat, Bhatni. Some bridges were constructed over small and medium rivers in medevial period by local rulers and business men which have now become obsolete. It is found that most of the bridges are of masonry arches wooden and trusses having insufficient water and carriage way.
After independence, the road network system has been improved to meet out socio economic needs of people. The new bridges have been constructed with standard road width and sufficient water way. Study has been conducted for existing new constructed bridge system over small river and alluvial region of Uttar Pradesh to set guidance for future course of action in replacing and providing new bridges to optimise the needs of the people. For this purpose, study has been conducted for sustainable option of minor bridges over small rivers discharge upto 410 m3/s. It is found that the well foundation bridge on medium type river is more efficient and economical than other type of foundation such as pile foundation, raft foundation.