Timber piles are a commonly used method for compacting soil and providing support and protection to waterfront structures. The decision to use timber piles is primarily based on the conditions of the site, particularly the water table.
Compared to other types of piles, timber piles are relatively lightweight yet strong, making them easy to handle. However, they are not as resilient to hard-driving as concrete or steel piles. As a result, careful consideration must be given to the selection and treatment of the timber, as the quality of the material and the absence of natural defects are crucial for ensuring durability and optimal performance.
Class of Piles
Piles are categorized into two main classes, namely Class-A and Class-B, based on their usage characteristics. This classification is made to differentiate between the various types of piles that are used in construction and civil engineering projects.
Class-A piles are typically used in situations where high load-bearing capacity is required. These types of piles are usually made from steel, concrete or timber and are designed to withstand significant vertical loads. They are commonly used for the construction of large buildings, bridges, and other structures where there is a need for heavy-duty support.
Class-B piles, on the other hand, are generally used in situations where the load-bearing requirements are less demanding. These types of piles are often made from smaller diameter steel or concrete and are designed to support lighter structures such as small buildings, residential homes, and other light structures.
The differentiation between Class-A and Class-B piles is important as it helps to determine the type of pile that is most suitable for a particular construction project. This ensures that the piles used in a project are able to withstand the required loads and provide the necessary support for the structure.
1. Class-A
Class-A piles are commonly utilized in the construction of various structures such as railway and highway bridges, trestles, docks, and warehouses. These piles are characterized by a minimum diameter of 30cm, which applies to both the butt diameter and the sides of the square. This minimum diameter ensures that the piles are robust and sturdy enough to support the weight and stress of the structures they are used for. With their strength and durability, Class-A piles are an ideal choice for construction projects that require a reliable foundation.
2. Class-B
Class-B piles are a type of foundation work that is utilized for purposes other than those specified in Class-A. These piles are also suitable for temporary work. However, it is essential to note that piles that are employed for compacting ground must not be smaller than 100mm in diameter or side in square piles.
In summary, Class-B piles are used for various foundation works other than what is specified in Class-A. They are also appropriate for temporary works. Moreover, when using piles for compacting ground, it is crucial to ensure that they meet a specific minimum size requirement, which is not less than 100mm in diameter or side in square piles.
Timber Piles Specfication
The given context describes specific requirements for the length and diameter of individual piles. For piles with specified length, there is a tolerance of plus or minus 30cm for lengths that are considered long, and a tolerance of plus or minus 60cm for lengths exceeding 12m. Additionally, for round piles, the ratio of heartwood diameter to the pile butt diameter must be no less than 0.8.
To ensure that the pile ends are properly prepared, both ends must be sawn at right angles to the length of the pile. Any knots and limbs on the pile must be trimmed to create a smooth surface. These requirements are essential for the proper functioning of the piles in their intended use.
Driving Timber Piles into Ground
The selection of piles for each bent should aim for uniformity in size to make it easier to place bracing members. The pile tip should be pointed, unless the pile is being driven in wholly soft strata. The shape of the pile tip should be a truncated cone or pyramid, with an area of 25 cm2 to 40 cm2 at the end, and a length that is 1 ½ to 2 times the diameter or side of a square. If the pile is being driven in hard materials, such as stiff clay or gravel, metal shoes of approved design should be attached to the tip. The head of the pile should be hooped with a suitable ring or wrapped with wires to prevent splitting and reduce brooming. Cushion blocks should also be provided to further protect the heads of the piles.
If the piles need to be formed from multiple lengths, the butting surfaces should be cut square to ensure contact over the entire cross-section of the pile. A thin steel plate placed between the butting surfaces will reduce the tendency to broom, and the pieces should be secured with steel tubes or flats. Splices in the middle of the pile should be avoided. If it is necessary to increase the size and length of the pile by building up sections, the joints should be staggered, and the timber members connected by bolts or screws.
In a pile group, the piles should be installed from the center to the periphery of the group or from one side to the other. The danger of damaging adjacent piles when driving a pile is greater in compact soils than in loose soils. When driving piles in loose sand, the order of installation should avoid creating a compact block of sand that would prevent further piles from being driven. If the soil is very soft, driving may need to proceed from outside to inside to retain the soil from flowing during operation.
Jetting of cases by means of water should be carried out if required, in a manner that does not impair the bearing capacity of piles already in place, the stability of the soil, or the safety of any adjacent buildings. Defective piles should either be removed or left in place as is convenient without affecting the performance of adjacent piles or the cap as a whole. Any sudden change in the rate of penetration that cannot be ascribed to the nature of the ground should be noted, and its cause ascertained if possible before driving is continued.
Handling of Timber Piles
Proper care must be taken to ensure that the piles are located correctly to avoid damage caused by excessive bending. It is crucial to handle treated piles with great care to prevent any harm to the wood’s surface. This can be achieved by using manila rope slings, hemp, or other means of support that do not cause any damage to the wood.
When handling treated piles, it is important to avoid dropping, brushing, breaking fibers, or penetrating the surface. The use of sharp pointed tools should be prohibited when turning or handling timber piles. Such tools can cause significant damage to the wood and weaken its structure.
It is permissible to have minor abrasions on the surface of treated piles below the cut-off level in the portions that will remain permanently underwater. However, any damage to the surface must be avoided to ensure the long-term integrity of the pile. Boring holes or driving nails into the surface of treated piles below the cut-off level to support temporary material or staging is strictly prohibited.
In summary, proper handling of treated piles is critical to ensure their longevity and safety. By using appropriate slings or support and avoiding damage to the surface, the piles can maintain their strength and stability over time.
FAQs on Driving of Timber Piles
What are the areas of application of timber piles?
Timber piles have multiple applications, including compaction of soils and providing support and protection to waterfront structures. These piles are commonly used in these contexts.
What are the types of timber piles and its uses?
Class-A piles are typically utilized for constructing railway and highway bridges, trestles, docks, and warehouses. To meet the specified requirements, the butt diameter or sides of the square should not be less than 30 cm.
On the other hand, class-B piles are employed for foundation work that is not included in the Class-A category, as well as temporary work. Piles that are used for ground compaction should have a diameter of no less than 100 mm, or a side measurement of no less than 100 mm in the case of square piles.
What are the standard specifications of timber piles?
The provided context contains three statements that need to be rephrased.
The first statement pertains to the length of individual piles and specifies that it should be within a certain range. To rephrase it, we can say that the length of the piles must fall within a specified range, with a tolerance of plus or minus 30 cm for long piles and plus or minus 60 cm for piles exceeding 12 m in length.
The second statement is related to the shape of round piles and specifies a ratio that must be met. To rephrase it, we can say that the heartwood diameter of a round pile should be at least 80% of its butt diameter.
The third statement concerns the preparation of the pile ends and involves sawing them and trimming any knots or limbs to create a smooth surface. To rephrase it, we can say that both ends of the pile must be cut perpendicular to its length, and any knots or limbs should be removed to ensure a smooth surface.