We know steel is an essential material for micropile construction. Except reinforcing bars, all structural steel used for micropile installation should be fabricated by shop drawings, previously approved by owner. The owner means not only the owner alone as he/they may not have geotechnical, structural knowledge. Owner can appoint qualified engineers for review, approve and supervision of micropile construction.
The shop drawing to be submitted by contractor should include:
a. Components of micropile
b. System design for corrosion protection
c. Attachment details of pile top
d. Details of bond length
The shop drawing along with working drawing, as discussed in previous post have to submit to owner for approval and review.
We know grout is sued in micropile construction, contractor have to submit the mix design for grout. This should include
• Every materials used in grout
• Mixing procedure of materials
• Placing procedure of grout
For reference, the submittal has to include acceptability of intended mix design verified by test results conducted in established laboratory.
Mill test certificates issued by metal industry have to be submitted to owner to have record. We have already discussed about metal reinforcing bars, casings, pipe for micropiles in our previous posts.
The reports should be properly marked, as materials delivered to owner. The inclusions for reinforcing bars are
• Ultimate strength
• Yield strength
• and elongation
At least two sets of coupon tests are required when mill certification not available for core steel or steel pipe that are used for permanent casing, for each load supplied to micropile project.
No work should be started until all submittals are received, approved and if required reviewed in writing by owner. At least 2 weeks should be allowed for review, providing comments, returning drawing submittals after complete set is received.
When additional time required for reviewing and approving due to unacceptable or incomplete submittals, the owner should not be claimed for delay. Any cost involvement due to wrong submission of documents will be responsibility of contractor.