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The reasons behind the trimming of pile head

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 In general, the bored piles are casted to a level higher than the required pile cut-off level. Pile cut-off level is usually similar or a little bit higher than the blinding level of a pile cap. the process of constructing a cast-in-situ pile involves the following steps:


  • installation of the temporary casing to prevent the soil collapse during the drilling process and to guide the drilling rig.
  • Drilling the pile to the required level and diameter.
  • Installation of a reinforcement cage. Reinforcement cage vertical bars will be extended above the pile cut-off level to improve the bonding with the pile cap.
  • The casting of concrete usually done with a tremie pipe. Tremie pipe will be lowered to the bottom of the pile, and then the concrete will be poured.
  • Once the casting is completed, the temporary casing will be removed.

It is a common practice to cast the concrete above the cut-off level. the concrete casted then removed for the following reasons:

  • during the casting process, the sediments, impurities, and laitance will immigrate from the bottom of the pile to the top. If we stop the concrete at the pile cut-off level. These impurities will form a weak layer of concrete, which results in reducing pile bearing resistance. Therefore, concrete is casted above the cut-off level, then this weak layer will be trimmed and removed.
  • In actual site practice, the details of construction sequence and access arrangements have a potential impact on the possibility of constructing piles to the correct level without the need for cropping.
Figure 1


Figure 2

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My name is Mohammad Hamdan, and I am a Civil/bridge Engineer with extensive professional background and experience in the field of construction. I have 10+ years of experience in the construction field. During my professional career, my emphasis has been placed on structural projects, mainly bridges, infrastructure and roads. Reading and practicing the design of structures is my passion.i was lucky to be a part of a big team that executed major highway interchanges. I believe in spreading the knowledge, thus, i compose these courses to share my experience and knowledge. My course focuses on the practical side of construction field. On other word, i am sharing some of what new engineers need to know about construction field. Beside working on construction field, i love writing some articles on my website ( curious civil engineer) Moreover, i wrote some engineering papers, you can check them  by searching my name on Google (Mohammad mamon Hamdan)