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Transportation Curriculum Coordination Council |
Leads are used to align the pile and hammer during driving. There are numerous different lead designs and box leads have been the most common on FDOT jobs in the past. Lead systems include three main types: swinging, semi-fixed, and fixed leads. Think of a roller coaster. The roller coaster is the hammer assembly and the tracks are the leads.
Swinging Leads-The leads are suspended from the boom by the cable and are not attached to the boom. A template is required when swinging leads are used to maintain the pile in proper position and alignment. |
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This is a photograph of a swinging lead - notice it is not attached to the crane or boom at the top or bottom.
 This is a photograph of a semi- fixed lead, where the leads are attached to the crane at the bottom but not at the top. |
 This is a photograph of a Fixed lead, where the leads are attached to the crane at the bottom. |
Semi-Fixed Leads-If the leads are attached to the boom at the top, then they are not attached at the bottom. If they are attached at the bottom, then they are not attached at the top. A template is required when semi-fixed leads are used to maintain the hammer and pile in proper position and alignment. |
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Fixed Leads-The leads are attached at the top of the boom and to the crane at the bottom with a brace. A template is not required when fixed leads are used to maintain the hammer and pile in proper position and alignment. |
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