SAES-Q-004 PDF – Installation of Piles and Conductors for Offshore Structures

This article is about SAES-Q-004 which is about Installation of Piles and Conductors for Offshore Structures at plants and download SAES-Q-004 PDF for Engineers, supervisors and project managers, QCs, QC Supervisors. This is saudi aramco standards of Civil Engineering based on international codes and standards and useful for Civil Construction knowledge to get job as engineers, QC Supervisors and QC managers, Engineering managers and technicians.

SAES-Q-004 PDF Download

SAES-Q-004

Installation of Piles and Conductors for Offshore Structures

This SAES-Q-004 standard focuses on the installation of piles used in offshore structures and coastal zones. It specifically excludes onshore pile installation.
The standard outlines the equipment, materials, personnel, and procedures required for installing offshore structure piles and conductors. Its purpose is to provide minimum installation requirements for offshore pile foundations. It also addresses potential problems and recommends remedial actions in case the pile installation does not go as planned.

For each specific project, the project specification should include details such as pile and conductor penetrations, lengths of concrete plugs, and any other construction requirements that complement the general requirements of this SAES.

It’s important to note that a project specification is typically issued for each project, which specifies requirements based on site-specific soil conditions, structure, pile types, and loads. Additionally, the pile installation specification should incorporate project site geotechnical data, pile design drawings, pile capacities with safety factors, pile acceptance criteria, driving criteria, and a description of planned remedial action.

The sections addressing conductor/piles in the standard offer guidance on their installation. Conductor/piles serve as foundation support for the structure and are used in oil drilling and production. However, the use of conductor/piles is generally not recommended due to conflicts in design and construction of these dual-use elements. The provided recommendations for conductor installation on a structure primarily aim to prevent soil formation damage and capacity reduction of nearby foundations and support piles.

Industry Codes and Standards for SAES-Q-004

Here are the additional codes and standards:

American Association of State Highway and Transportation Officials:

• AASHTO T26: Standard Method of Test for Quality of Water to be Used in Concrete-HM-22

American Society for Testing and Materials:

• ASTM C150: Standard Specification for Portland Cement
• ASTM C494: Standard Specification for Chemical Admixtures for Concrete
• ASTM C618: Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzalan for Use as a Mineral Admixture in Concrete

American Petroleum Institute:

• API RP10B: Recommended Practice for Testing Oil-Well Cements

These codes and standards provide further guidance and specifications related to quality, materials, and testing requirements in the context of concrete and cement used in offshore pile installation and related activities covered by SAES-Q-004.

Driven Pile Installation

6.1 Pile Driving

• The contractor will stab and pre-drive piles in the corner legs of the platform by placing the hammer weight on each pile. Stabbing should follow a diagonal pattern to minimize drift.
• For tripod platforms, only two piles may need to be pre-driven to prevent interference with batter piles.
• The expected penetration under pile weight and hammer weight should be analyzed before installation during the pre-installation planning.

6.1.2 Driving Sequence of Piles

• If the platform jacket is not level after setting and pre-driving, the contractor will first drive the pile at the lowest corner of the jacket. The jacket will then be leveled and connected to the driven pile with a temporary welded connection. The remaining piles will be driven to the required depth. If needed, the first pile will be spliced and re-driven. Efforts should be made to maintain the specified elevation of the jacket top during driving.

6.1.3 Driving Sequence of Well Conductors

• Well conductors on multi-well platforms will be driven starting from the center of the group and working towards the outside.

6.1.4 Test Pile

• The first pile driven to design penetration or refusal is considered the test pile. It is used to evaluate pile capacity and setup at the site. Dynamic measurements and CAPWAP analysis are performed on the pile after at least 12 hours of setup. The report is approved by the Saudi Aramco Representative. Based on the test pile’s characteristics, the Contractor and Saudi Aramco Representative will re-evaluate splicing, soil stratigraphy, and pile design parameters. The lengths of additional pile sections may be revised to minimize the risk of refusal before achieving design penetration due to driving interruptions.

6.1.5 Insurance Piling

• The Contractor should have a minimum 9-meter long section of piling available at the site in addition to the design length of piling. This extra length covers the possibility of needing to drive piles deeper than the design penetration. Insurance piling allows pile driving to continue while additional pile material is brought to the site.

6.1.6 Closure Plates (Steel or Rubber Diaphragm)

• Closure devices are used on the lower end of the jacket columns and pile sleeves to provide buoyancy. They should be designed to avoid interfering with the installation of piles.
• Closure devices should not be removed by punching them off with the piles. Diaphragm rupturing tools can be used to remove the closure plates.

6.1.7 Stabbing Guides

• Add-on pile sections should have guides to assist in stabbing and aligning them with the already installed sections. The fit between the pile and the guides should be tight and consistent.
• The guides should be designed to support the full weight of the add-on pile section before welding the sections together.

6.1.8 Lifting Eyes and Weld-on Lugs

• Lifting eyes and weld-on lugs used for pile handling should be designed to withstand the stresses associated with initial pile pickup, stabbing, and impact loads that may occur during pile handling.
• When lifting eyes and weld-on lugs are used to support the initial pile section from the top of the jacket, each eye or lug should be capable of supporting the entire hanging weight.
• The padeyes should be designed to resist all possible bending loads that may occur out of the plane.
• If lifting eyes and/or weld-on lugs are present on lengths of pile that will remain in service, they should be removed by torch cutting 6 mm from the pile steel surface. The cut area should then be ground smooth to prevent damage to internal jacket leg elements such as packers during pile driving.

Pile Driving Requirements:

Pile driving should be conducted continuously or with minimal interruptions to minimize increases in driving resistance during delays. Setup tests with Dynamic Measurement System (DMS) monitoring and analysis should be performed on at least one pile per structure to ensure sufficient capacity at or near the final penetration.

Adequate backup pile hammers should be provided and readily available, especially when driving through soil layers that may experience increased resistance (setup) during delays.

6.4.1 Terminal Penetration:

• Terminal penetration refers to the penetration achieved at the completion of pile driving.
• The capacity and penetration of the pile should be checked against design requirements for acceptance.
• Piles should be driven to the design penetration specified for the site or to refusal.
• Design penetration is determined based on the static axial pile capacity and lateral load requirements calculated according to the procedures in SAES-M-005.
• The calculated static axial capacity may be revised based on data obtained during pile driving monitoring. Any changes to the required pile penetration must be approved by the Supervisor, Civil Engineering Unit, Consulting Services Department, Saudi Aramco.
• If the pile refuses to penetrate to the design depth and the calculated static axial capacity falls short of the design requirements, remedial action should be taken to meet the design pile capacity.

6.4.2 Driven Pile Refusal:

• Pile driving refusal occurs when the pile driving resistance exceeds certain blow count criteria.
• Refusal is defined as either 300 blows per 30 cm for at least 150 cm of penetration or 800 blows per 30 cm of penetration. These criteria are adjusted proportionally if the weight of the pile exceeds four times the weight of the hammer ram, but they should not exceed 800 blows for 152 mm of penetration.
• If there has been a delay in pile driving operations for one hour or longer, the refusal criteria mentioned above do not apply until the pile has advanced at least 25 cm or the hammer has operated at the manufacturer’s rated speed for at least 15 minutes after the resumption of pile driving.
• For steam and diesel pile hammers, the minimum acceptable pile hammer efficiency at refusal should be 90%.
• Pile driving should be terminated when driving stresses exceed 90% of the yield stress.

6.4.3 Minimum Driving Resistance:

• The minimum final driving resistance for driven piles should be specified for each specific job.
• The criteria for minimum driving resistance should be determined based on dynamic analyses such as wave equation, geotechnical investigation data, past experience in the area, and/or pile load tests.

6.4.4 Cushion Blocks:

• Prior to starting driving, the contractor and Saudi Aramco Construction Engineer should inspect the cushion block. If necessary, the cushion block should be replaced to ensure uninterrupted driving to the design penetration.
• Acceptable ranges for cushion stiffness should be defined for locations where pile refusal is anticipated. If measured cushion stiffness falls outside the acceptable range, the cushion block or hammer should be replaced.

6.4.5 Pile Splices:

• Splices made on piles extending more than 5 m into clay layers at depths exceeding 15 m below the seafloor may experience significant increases in driving resistance (setup), making further driving challenging.
• Therefore, splice locations should be selected to minimize the risk of refusal due to increased driving resistance.

6.4.6 Grout Plug:

• When the soil plug is removed from the pile and the pile is re-driven or a predrilled hole is used to facilitate driving, a grout plug must be placed to develop end bearing of the pile.
• The pile should be cleaned out as described in Paragraph 7.2.7, and the grout plug should be placed following the guidelines in Paragraph 9.3.
• The length of the grout plug should be specified for each specific job.

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