Pile driving hammers are used to drive piles into the soil to create support for buildings or other structures like retention ponds and dams. Driven piles consist of natural materials or pre-manufactured structural shapes built to precise tolerances utilizing high strength materials and reliable quality control. consist of natural materials or pre-manufactured structural shapes built to precise tolerances utilizing high strength materials and reliable quality control. They may be driven either vertically or at an angle to the vertical. Piles are driven using a pile hammer. When a pile is driven into granular soil, the soil so displaced, equal to the volume of the driven pile, compacts the soil around the sides since the displaced soil particles enter the soil spaces of the adjacent mass which leads to the densification of the mass.
There are different types of pile driving hammers used in construction, some of them are explained below.
Diesel Hammers
Modern-day diesel hammers are a must-have in the foundation industry. Diesel pile hammers are used to drive piles into a supporting soil layer. The mode of operation is similar to that of a hammer used to drive a nail. The piston activates the pump lever during its fall. The diesel fuel is in that manner sprayed onto the surface of the impact block. The air in the cylinder is compressed as soon as the piston runs past the exhaust openings. The modern hammers come with an increased compression pressure that drives the piston and the impact head below it on the material to be driven. Modern diesel pile hammers are equipped with adjustable fuel pumps for regulating the stroke of the piston and therefore the impact energy. This is a particular advantage when soil formations change. Optionally a hydraulically actuated fuel pump with infinite settings is available.
Hydraulic hammers
Hydraulic hammers are a modern type of piling hammer used instead of diesel and air hammers for driving steel pipe, precast concrete, and timber piles. Modern hydraulic hammers come with a grease port and are provided for automatic and/or manual greasing of the demolition tool. This prevents damage or premature wear caused by a lack of grease. The unique one-piece design eliminates the need for mechanical springs and overly heavy mounting brackets. The net result is a minimization of machine wear and improved operator comfort for greater reliability and productivity. It is available in different models, divided into large, medium and small and available in various versions. Combining maximum power with the effectiveness of intelligent technology, hydraulic hammers are unbeatable when it comes to completing the toughest jobs in the shortest possible time-frame – whether it’s the biggest demolition jobs, primary breaking in quarries, digging foundations or excavating huge rail and road tunnels.
Vibratory hammers
Vibratory hammer is used to drive sheet piles, pipes or other elements into the soil by vertical vibrations. The adjacent soil particles are put into motion and thus the soil is ‘loosened’. The dynamic weight of the hammer will drive the elements into the soil. Vibratory technology is easier than most conventional technologies and it also cuts down operating time and costs. Modern vibratory hammer with an adjustable static moment is suitable for the piling and extracting of steel sections such as sheet pile walls, H-beams and pipes as well as alternative foundation methods like Vibro, cast-in-place, gravel, and sand piles. The operator can change between the minimum and maximum static moment with the push of a button or adjust defined intermediate positions. Depending on the application, you can choose from a variety of hammers in normal and high-frequency models. For sites where the surrounding soil must not be allowed to vibrate such as in urban areas or the vicinity of old buildings.
Steam hammers
Steam hammer is an industrial power hammer driven by steam that is used for tasks such as shaping forgings and driving piles. Typically the hammer is attached to a piston that slides within a fixed cylinder, but in some designs, the hammer is attached to a cylinder that slides along a fixed piston. Modern steam hammers use steam or compressed air to raise the ram. At a point in the upstroke, the valve is moved and the ram floats to the top of the stroke; the ram then fails by its weight and makes an impact. These hammers are generally referred to as “airstream” because they can be operated by either air or steam; a few are operable by only one or the other. Modern steam-hammer may have one or two supporting frames. The single-frame design lets the operator move around the dies more easily, while the double frame can support a more powerful hammer. Deep foundations are needed, but a large steam drop hammer will still shake the building that holds it. This may be solved with a counterblow steam hammer, in which two converging rams drive the top and bottom dies together. The upper ram is driven down and the lower ram is pulled or driven up. These hammers produce a large impact and can make large forgings. They can be installed with smaller foundations than anvil hammers of similar force.
Conclusion
Only a few years ago piles of 70-ton design load capacity; were considered exceptional. Today loads of 200 tons per pile are not uncommon. In a few years, it is to be expected that piles loaded to 300, 400, and even 500 tons will be replacing expensive caissons for high-column loads. This will make the use of larger hammers mandatory. Oscillators of the high frequency or resonant type will probably make use of linear hydraulics, and this should make for a high force output from a small package and minimize the number of moving parts in the system.
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