3. Impact Noise from Pile Driving

Whatever hammers we discussed so far, a drop hammer, single acting hammer, all these impact hammers are noisy hammers, that means it results in lot of noise prediction during the driving operation. So, the impact hammers produce the highest sound pressure levels. So, there are different types of noises. One is because of the hammer the ramming against a pile head, that results in one type of noise. The other type of noise is due to running of your air compressor or steam boiler, all these things also results in production of noise. So, there are basically 2 types of noise which are produced by impact hammer, one is your impact noise produced by the ram striking the pile, and other one is produced by the operating steam air, or the diesel exhaust as it is exhausted from the cylinder.

Impact hammers, like the drop hammer and the single acting steam hammer, generate significant noise during their operation. This noise is mainly categorized into two types: impact noise and operational noise. Impact noise occurs when the hammer strikes the pile, creating a loud sound as the force is transferred. On the other hand, operational noise is produced by the machinery involved in the hammer's operation, such as air compressors generating steam or the diesel engines powering the equipment.

You can think of impact noise like the sound of a heavy object striking a surface, similar to a hammer hitting a nail. The sound of the nail being driven into wood is the result of the hammer's impact. Similarly, when a hammer strikes a pile, it produces a loud noise that can be compared to that initial striking sound. The operational noise can be likened to the hum and rumble of machinery in a factory, where various machines running together create a continuous sound that contributes to the overall noise in the environment.

So, let us work out a simple problem on the hammer selection. A single acting hammer is used to drive concrete pile which weighs 15,000 kg, so the weight of the concrete pile is given as 15,000 kg, you are going to recommend the hammer weight needed, recommended hammer weight and the minimum hammer weight required. As I told you the basic rule for the single acting hammer is hammer weight should be equal to the weight of the pile. So, the concrete weight pile is 15,000 kg, so recommended hammer weight is nothing but 15,000 kg. In the worst case, if 15,000 kgs of heavy hammer is not available in the market. In that case, the minimum requirement is you should never go below one third of the weight of your pile. That means minimum weight needed is Minimum hammer weight = 0.33 × 15000kg = 4950kg. At least we should never go below this. So, this is a basic guideline that we should keep in mind.

When selecting a hammer for driving a concrete pile, it is crucial to base the weight of the hammer on the weight of the pile itself. In this context, the preferred hammer weight should match the weight of the pile (15,000 kg). If such a hammer is not available, a minimum weight requirement needs to be established, which ideally should not fall below one-third (approximately 4,950 kg) of the pile's weight. This guideline is vital to ensure proper driving and prevent damage during the installation process.

Think of it as using a tool that needs to balance with the material you're working on. For example, when using a wrench to tighten a bolt, the wrench size needs to be appropriate for the bolt, or it won't work effectively. Using a hammer that is not the right weight for a concrete pile is like trying to use a toy wrench on a real bolt; it just won’t do the job properly. You can imagine the hammer needing to be heavy enough to effectively drive the pile into the ground without breaking it or losing efficiency.

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