Pile Drivers

 

Diesel Hammer: A modern diesel pile hammer is a very large two-stroke diesel engine. The weight is the piston, and the apparatus which connects to the top of the pile is the cylinder. Piledriving is started by having the weight raised by auxiliary means — usually a cable from the crane holding the pile driver — which draws air into the cylinder. Diesel fuel is added/injected into the cylinder. The weight is dropped, using a quick-release. The weight of the piston compresses the air/fuel mixture, heating it to the ignition point of diesel fuel. The mixture ignites, transferring the energy of the falling weight to the pile head, and driving the weight back up. The rising weight draws in fresh air, and the cycle starts over until the fuel runs out or is stopped by the pile crew.

 

Vertical Travel Lead Systems: The vertical travel lead, referred to as "VTL" system, was first developed and patented by C.W. Bermingham in the 1970s. This lead system was developed in response to the fundamental limitations of either a fixed lead or swinging lead system. The fixed lead system is well suited to level job sites with few obstructions and has the advantage of faster positioning of the lead. The hanging lead is very adaptable to different elevations and batter piles but takes much longer to position. The Vertical Travel Lead was developed to combine the fast and accurate positioning of fixed leads, with the ability to adjust the height of the lead base up or down. The VTL lead is connected to the boom by a sliding connection, which allows the lead to be elevated or lowered below grade. The VTL system has become the industry standard in Canada, US Railway Construction, and many parts of the USA.[citation needed] Vertical Travel Leads come in two main forms: Spud and Box Lead types. Box leads are very common in the Southern United States and Spud Leads are common in the Northern United States, Canada and Europe.

 

A hydraulic hammer: is a modern type of piling hammer used in place of diesel and air hammers for driving steel pipe, precast concrete, and timber piles. Hydraulic hammers are more environmentally acceptable than the older, less efficient hammers as they generate less noise and pollutants. However, in many cases the dominant noise is caused by the impact of the hammer on the pile, or the impacts between components of the hammer, so that the resulting noise level can be very similar to diesel hammers.

 

Vibratory Pile Driver: contain a system of counter-rotating eccentric weights, powered by hydraulic motors, and designed in such a way that horizontal vibrations cancel out, while vertical vibrations are transmitted into the pile. The pile driving machine is lifted and positioned over the pile by means of an excavator or crane, and is fastened to the pile by a clamp and/or bolts. Vibratory hammers can either drive in or extract a pile; extraction is commonly used to recover steel "H" piles used in temporary foundation shoring. Hydraulic fluid is typically supplied to the driver by a diesel engine powered pump mounted in a trailer or van and connected to the driver head through a set of long hoses. When the pile driver is connected to a dragline excavator, it is powered by the excavator's own diesel engine. Vibratory pile drivers are often chosen to mitigate noise, as when the construction is very close to residence or office buildings, or when there is not enough vertical clearance above the foundation to permit use of a conventional pile hammer (for example when retrofitting additional piles to a bridge column or abutment footing). Hammers are available with several different vibration rates, ranging from about 1200 vibrations per minute to about 2400 VPM; the vibration rate chosen is influenced by soil conditions at the site and other factors such as power requirements and purchase price of the equipment.