Chapter 6
Contractor and Equipment Arrive on Site
Contents
- This Chapter contains an overview of the drilled shaft construction from the Inspector's viewpoint and an overview of the Inspector's responsibilities during this phase of drilled shaft construction.
- A short quiz is provided at the end of the Chapter.
Just as the Contractor has their tools, the Inspector needs to have their tools also. Without the proper tools, the Inspector cannot perform their duties properly.
The Inspector should not go to the site without the "tools" discussed below.
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Tools |
- Approved Drilled Shaft Installation Plan
- Project Plans & Specifications
- Any Special or Technical Provisions
- Required Forms/Reports
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- Hard hat, boots
- Eye & ear protection
- Measuring tapes
- Scale, level, sampler
- Weighted tape (100')
- Calculator, pen, pencil
- Builders Square
- Life or reflective jacket
- Slurry testing equipment
- Concrete testing equipment
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This photo shows some of the Inspector's tools, such as hard hat, field book, measuring tapes, flashlights, safety glasses,
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The Drilled Shaft Construction Process
Illustrated below is the drilled shaft construction process from the Inspector's viewpoint. During each of these phases, the Inspector has specific responsibilities relating to verifying, measuring, checking, and documenting.
Because the Inspector has no specific responsibilities during the development of the Drilled Shaft Installation plan, other than to become familiar with it, and attend pre-construction meetings, as discussed earlier, we will start with "Contractor Arrives On-site".
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The Contractor mobilizes to the site. They must bring the equipment specified in the accepted Drilled Shaft Installation Plan. |
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Excavation of the shaft begins. Typically at this stage a "Trial or Technique" shaft is constructed to determine if the methods and techniques will work. |
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The specified reinforcing cage is constructed and positioned in the excavation. |
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The specified concrete is placed into the excavation. |
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The specified load or integrity testing is performed to document shaft construction. |
The Contractor has arrived on-site and the Inspector has some basic responsibilities to perform at this time.
These include:
- Check the Equipment
- Check for Protection of Existing Structures
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Check the Equipment
When the equipment arrives on site, it is the Inspector's responsibility to verify that the equipment brought on-site matches the equipment listed in the approved Drilled Shaft Installation Plan.
The Inspector does not have the authority to reject equipment, but must accurately document the Contractor's equipment. The equipment would have been detailed in the Contractor's Drilled Shaft Installation Plan. In some instances the Contractor may not bring the equipment or tools or brings different tools other than proposed. By documenting what equipment is on-site, should equipment related questions arise later, the Inspector's documentation serves as a record.
Some of the things to check are shown and discussed below.
Is the drill rig the specified one? |
Are the bits the right type? Soil or rock; the correct diameters; single flight or double flight; single cut or double cut? |
| Are the buckets, barrels and other tools as listed in the approved Drilled shaft Installation Plan? |
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Pictured above is an Inspector checking the tremie. Tremies are to be clean and smooth on the inside. |
Pictured above is the Inspector checking the dimensions of a belling tool. It needs to be in the extended position for the maximum diameter to be measured. The height needs to be measured also, to add to the kelly bar length for total depth to bottom of hole. |
In this photograph the Inspector is verifying the length the casing to be used. The overall length is measured and documented. |
In this photograph the Inspector is verifying the diameter of the casing to be used. He is measuring the ID and the OD, which also provides the wall thickness of the casing. |
Check for Protection of Existing Structures
Some projects will be near existing structures that could possibly be damaged by the construction. Typically in these cases, the Contractor was required to submit a Protection of Existing Structures Plan. In some instances, the construction, such as vibrating of casing in or actual drilling, can create vibrations that can impact structures in the vicinity, such as cracking of walls, etc.
Generally, the specifications will outline the requirements of the Plan and it is the Contractor's responsibility to execute that plan once approved.
It may call for surveying of potentially effected structures, within a specified distance, to document their condition prior to construction. In addition, monitoring, for vibration and/or noise may be specified, also for a specified distance, during construction.
If the project requires Protection of Existing Structures, the Inspector needs to review the approved plan and document that the Contractor is executing it.
I have completed Chapter 6 and am ready to take the Quiz
