Piles and Pile Foundations: An Overview of Their Functions and Types
Piles and pile foundations have been used for thousands of years to provide support in areas with unfavorable soil conditions. From the Neolithic inhabitants of Switzerland to the modern-day structures in cities like Venice and Venezuela, piles have played a crucial role in enabling construction in challenging environments. The primary function of piles is to transfer loads that cannot be adequately supported by shallow foundations to deeper, more stable layers of soil. There are two main types of piles: bearing piles and friction piles. Bearing piles are driven through poor soil until they reach a stratum with good bearing capacity, relying on point resistance for load-carrying capacity. Friction piles, on the other hand, are installed in deep layers of soil with low bearing capacity and rely on skin friction for load transfer. Determining the load capacity of a single pile requires a static load test, which can be expensive but is the most reliable method. The allowable load is determined by applying a factor of safety to the failure load. Tension piles are used to resist moments in tall structures and upward forces, while laterally loaded piles support loads applied at an angle to the pile axis. In conclusion, piles and pile foundations are essential for constructing buildings and structures in areas with challenging soil conditions. By understanding the different types of piles and their functions, engineers can ensure the stability and safety of their designs.