History Of Piling In the early days of civilisation[2], from the communication, defence or strategic point of view villages and towns were situated near to rivers and lakes. It was therefore important to strengthen the bearing ground with some form of piling. Timber piles were driven in to the ground by hand or holes were dug and filled with sand and stones. In 1740 Christoffoer Polhem invented pile driving equipment which resembled to days pile driving mechanism. Steel piles have been used since 1800 and concrete piles since about 1900. Pile foundations have a rich history dating back to ancient times when they were utilised to provide support for structures erected on soft soils. In Switzerland, there exists an ancient city approximately 6000 years old, where wooden piles were constructed to hold the buildings. Moving forward to the Roman era, we find that piles, crafted from either stone or timber, were commonly employed to support bridges, aqueducts, and other architectural wonders. One of their most iconic achievements was the Colosseum, an engineering marvel which relied on piles for its solid foundation and was built during the first century AD. As time progressed into the Middle Ages, pile foundations remained an essential element in European construction, providing vital support to structures such as cathedrals and castles. These foundations mainly consist of wooden piles driven into the ground using hefty hammers. The 19th century brought significant advancements to pile foundations due to the introduction of novel materials like concrete and steel, with the advent of steam-powered pile drivers, driving piles deeper than ever to support heavier loads. The 20th century marked yet another milestone for pile foundations with the invention of hydraulic pile drivers and other specialised equipment. Today, pile foundations have worldwide applications in various structures, including skyscrapers, bridges, and other projects requiring a sturdy base on soft or unstable soil. In Nepal, Timber Piles are also seen used in history for the structure built close to river and soft soil. The application of cast in situ Pile is started about 25 to 30 years back with the demand of multi storied building and bridges. Initially hand auger was widely used for drilling in Kathmandu valley for Piling in soft soil. With increase in demand of Piling DMC and Truck mounted rig are in operation to this date. In recent years (10 -12 years) High-capacity Piling equipment’s are widely used in Nepal for bridge & Building projects. Numerous of highcapacity Piling rigs are currently deployed Kanchanpur-Kamala Road Improvement Project, Kathmandu- Terai /Madesh ast Track Project. At some bridge site, manual excavation for Piling for large diameter (2.2m) is also reported in Nepal. Pile Types Based on Load-bearing Principle Friction Piles Friction piles, also known as floating piles, use their whole skin to transfer the structural loads into the ground. They are used where you can’t find strong stratum at achievable depths. These piles use the phenomenon of friction to interlock themselves with the surrounding soil and transfer their loads. Owing to this interlocking, they seem to be suspended; that is why they are called floating piles. End-Bearing Piles End-bearing piles use sturdy and resilient stratum of the soil to transfer heavy structural load to the ground. They are constructed where you can find a strong enough layer of rocks at an achievable depth. They are called end-bearing piles because the load is only transmitted through both ends rather than the whole skin of the piles. Pile Types Based on Piling Technique Bored Piles These piles are constructed by digging a borehole and removing the soil to install or construct a pile. This technique is used where engineers find sufficiently compacted and cohesive soil to support the heavy loads of the building. Driven Piles Driven piles, on the other hand, are inserted into the ground, without removing the soil, with the use of hydraulic hammers or pile-driving machines. These piles compact the surrounding soil while they are driven into the ground. This technique is used in such a situation where the soil is not compacted enough to support a friction pile. Pile Types Based on Construction Materials Timber Piles Timber, as we have mentioned earlier, is the oldest known material that has been used for piling. Timber is readily available and provides durability and economy. However, timber piles can support a limited amount of structural load and require proper seasoning and treatment before installation. Concrete Piles Concrete is a highly strong material and can bear extreme compressive loads under any condition. Its discovery opened the doors to new possibilities and revolutionised the construction rulebooks completely. However, the concrete is a brittle material with low tensile strength which makes it a weak choice for lateral loads. Steel Piles Steel piles, due to high strength and density, usually have a very small cross-section, which makes it easy to drive them into the ground. Steel piles can be made in different shapes, such as H, L and T sections or cylindrical shapes. They, however, can corrode under extreme chemical conditions of the soil and require proper treatment before installation. Composite Piles Composite piles are basically a combination of more than one piling material. Such as reinforced concrete piles are constructed by combining steel and concrete to achieve high compressive as well as tensile strength to handle extreme vertical and lateral loads of the building.