Dear reader here we will learn about task to be performed for micropile installation; in the last post we have learnt about reinforcement required for micropile foundation; both reinforcing bar and pipe or tube.
The task should consist of providing required engineering & design services, if applicable, including supervision, materials, labor, and equipment required to execute all tasks to install, testing micropiles as per specification provided by standard code and requirements of building officials.
The contractor has to install a system of micropile that has capacity to meet the requirements of design as specified in the drawing.
The capacity developed should be checked by testing and as per specification provided in contract agreement. The tasks that have to be conducted in design office and also at field are as follows:
a. The first task of this foundation work are geotechnical investigation and survey as follows:
• Site exploration
• Geotechnical exploration
• Site survey
• Probable constraints encountered during installation process.
b. The next task consists of
• Making decision of use appropriate micropile system
• Pre-contract test program and its requirements
• Procurement method
• Prequalification levels
• Types of specification say for
1. Materials and testing
ASTM and AASHTO Specification Related to Micropile Installation
c. Determine easements of tasks; here the conditions at site and local availability of required labor, equipments and materials are studied carefully.
d. Definition and quantification-qualification of factors of safety and overall scope of tasks to be conducted in following steps and design of piled structure is studied here.
e. Structural loads that have to be transferred thorough micropile systems are determined in this task; both horizontal and vertical loads are considered.
f. Calculation/determination of tolerance in total service structural movement, when micropiles suffer excessive deflection; in this case pipe or casing is introduced.
g. Definition of the service life of structure or micropile (permanent/temporary) and corrosion protection based on ambient environment and life cycle.
h. Number and type of tests (before construct and during production).
i. Load on micropiles, their orientation, spacing and location.
j. Depth of bearing stratum and minimum total length of pile.
k. Details of component of micropile.
l. Determination of length of load transfer or depth of the rock socket.
m. Corrosion protection details.
n. Connection details of pile to structures under both static and earthquake loading.
o. Drawing preparation and record keeping.
p. Evaluation of different test results.
q. Construction methods, sequencing and co-ordination of work.
r. Requirements of QC/QA program.
s. Supervision of construction work.
t. Monitoring and maintenance .
Additional standard and referenced codes are as follows: