Chapter 5: The Heavy Hammers of Pile-Driving Equipment
Pile drivers represent some of the unique and specialized pieces of heavy machinery you will find at a construction site. Crews typically utilize them during projects that require the use of deep foundations over shallower foundations.
The site may need a deep foundation due to soil composition and other types of constraints. Laying a deeper foundation means building loads must be transferred much further down into the earthhappens through the use of:
Pile drivers, which are incredibly powerful hammers, push piles deep into the ground. Extensive excavation and drilling may be needed to prepare the site beforehand, but the pile drivers will do the rest of the work.
The Power Behind Pile Drivers
Numerous types of building materials, most often steel and concrete, comprise the reinforced foundations that transfer the load deeper into the earth. The construction of highway systems, bridges and other building projects that require a deep foundation and support also rely on piles. Micro-piles, or mini piles, might be used for this type of structural support and are commonly made of steel.
Pile drivers are large mechanical devices operated through hydraulics, steam power or diesel fuel. The large weight drives the pile into the earth. It is raised like a hammer and then, when it reaches the designated high point, it is released and the force of it falling drives the pile into the ground.
Pile drivers can be static or mobile, depending on the amount of force needed and requirements of the job site. As with cranes and excavators, pile drivers come in different shapes, sizes and designs, offering flexibility for specific tasks. Below we look at some of the most common pieces of equipment used for creating foundation supports.
1. Diesel Hammers: The Engine That Moves the Weight
Through the utilization of diesel fuel, the hammer acts like a very large engine. A crane hoists the weight, which acts as a large piston. Hoisting allows air to flood into the cylinder, or pile, below. When the fuel is added and injected, the weight drops quickly. This compression of air and fuel creates friction and heat, leading to ignition.
The force of the mixture’s combustion then has enough power to drive the piston, or dropped weight, back upward. Again, this process draws in air and will continue repeating itself until manually stopped or the fuel is expended. This continuous motion of the weight hitting the pile acts as the hammer, slowly driving the pile into the desired spot.
2. Vertical Travel Lead Systems: An Alternative to Traditional Pile Driving
These types of pile drivers are unique in that they use a vertical lead. This setup is particularly useful when limitations inhibit traditional pile driving mechanisms. Originally, the hanging lead of early designs could be released at different elevations, but that required more time to position.
The vertical travel lead reduced this time, and it has been developed further to allow for much faster positioning. The lead connects to a boom and then a sliding connection. This formation allows for the lead to lower or elevate at the desired height.
3. Hydraulic Hammers: Driving in Pipes, Concrete and Timber
These are the most modern type of pile driver used in construction today. By using hydraulics, these hammers drive pipes, concrete and even timber deep into the earth. They also cause less environmental damage than diesel hammers because they are:
- More efficient
- Generate less pollution
- Create less noise
However, the impact of the hammer itself and the sheer force of the weight hitting the pile always produces a very loud sound.