The Constructor

Bored Cast in Situ Concrete Pile, Its Construction and Applications

bored cast in situ pile construction

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What is cast in situ concrete pile?

Bored cast in situ pile is constructed by digging a hole in the ground by suitable means such as percussive or rotary method with the use of temporary or permanent casing or drilling mud. After that, the construction is finalized by filling the hole with reinforced concrete. In this article, different aspect of bored cast in situ concrete pile construction along its application conditions will be discussed.

Procedure for Construction of bored cast in situ pile

In this section, procedure used for the bored cast in situ pile construction is presented:

Prior to the commence of pile construction operation

Setting out pile points

Fig.1:Set out pile location

Plan preparation for rig movement

Boring process

  1. Position the rig over the established pile point. Check the accuracy of the point by comparing it with other reference points.

Fig.2:Positioning rig on pile spot

2. Diameter of the cutting tool shall not less than the required pile diameter by more than 75mm.

3. After rig positioning, drive the casing into the ground. Drive steel casing to a minimum a depth of 1 m below the ground level to take lateral loads and movements at site. The steel casing also combat difficulties due to groundwater during piling.

4. Additionally, provde permanent steel casing or liners in the case of loose soils as per consultant’s advice.

5. stabilize the borehole during boring process using bentonite or other suitable means.

6. Estimate specific gravity of bentonite at regular intervals. Consistency of the drilling mud shall be controlled throughout the boring as well as concreting operations. This measure used to stabilize the borehole as well as avoid concrete getting mixed up with the thicker suspension of the mud.

7. Practiced great care to guarantee straight piles driven.

Fig.3:Drilling pile borehole

8. It is recommended to carry out penetration tests to estimate ‘N’ value of the founding strata. In addition to take and maintain soil or rock samples from the founding strata, for future reference.

9. It is also advisable to take soil samples from each intermediate soil strata at the depths specified in the soil test report.

10. Finally, end the boring process upon reaching the designated boring depth. Check the borehole depth through measuring bailer pipe length after its removal from the borehole, and use sounding technique to recheck the borehole depth.

Reinforcement placement

Fig.4:Prefabricated reinforcement cage for pile construction

Fig.5:Lowering pile reinforcement cage into borehole

Fig.6:Reinforcement cage cover block

Fig.7:Reinforcement cage rebars

Bored cast in situ pile Concreting

Fig.8:Tremie pipe lowered into borehole of a pile

Fig.9:Pile concreting using tremie method

Fig.10:pile concreting tremie method

Applications of bored cast in situ concrete pile

bored cast in situ pile is a strong choice in the following conditions:
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