An introduction to steel piles

AN INTRODUCTION TO STEEL PILES

Prepared By:-Uday Nigam

Table of Contents Steel Pile Usage Specifications of Steel Piles Fabrication of Steel Piles Painting of Steel Piles Installation of Steel Piles

Steel Pile UsageJetty

Jetty Portion

Trestle Approach Portion

Flare Portion

Mooring Dolphins

Breasting Dolphins

Unloading Platform

Catwalk Supports

Specifications of Steel Pile Zone divisions of steel pile:- Atmospheric zone Splash zone Submerged zone Below Sea bed zoneThese zones are further divide into 6 zones.

Fabrication of Steel Piles At the time of last / middle pipe fit up extra care is required for proper

alignment.

In fit up root gap should not be more than required as per WPS.

In fit up edge preparation angle should be as per Approved WPS.

Spools joint is set with root gap of 3 to 4 mm all around the circumference

Once the above is achieved, internal joint tacks are to be done using 2.6/ 3.15 / 4 mm E 7018 / E 9018M electrode. Each tack will have length 1.5"/ (or min 6 times of electrodes size).

Welding should not be in weaving or weaving should not be more than 2.5 times of electrode dia size. Root pass shall not be weaved .

Fabrication of Steel Piles(Contd.)

All electrodes having low-hydrogen coverings conforming to AWS A5.1 shall be baked for at least two hours between 500°F and 800°F [260°C and 430°C]

Root joint will be cleaned by grinding/wire brush and subsequent hot pass.

Hot pass will also be done using above sequence. Root pass cleaning shall be by grinding/wire brush. Hot pass welding shall be done without any reasonable interruption. Pipe shall not be rotated during welding.

After completion of root and hot pass, joint will be taken for SAW

QC points during/post Welding Excessive reinforcement should not be more than 3 to 5

mm. Flux from damaged packages shall be discarded or shall

be dried at a minimum temperature of 500°F [260°C] for one hour before use.

Flux that has been wet shall not be used. Travel speed of welding should be fast as much as

possible as in manual welding it is advisable 50 -100 mm/minute and in SAW 300- 400 mm/minutes minimum.

Pipes rotation should be controlled with respect to wire feeding in SAW as speed of roller preferably should be 80 % speed of wire feeding for proper fusion/ penetration.

Blasting & Painting of Steel Piles

Surface Preparation Blasting Painting Post painting quality checks

Blasting & Painting of Steel Piles(Contd.)

Surface preparation:- Oil or grease, salts, dirt, chalk marks and similar contaminants shall be

removed as far as possible, prior to surface preparation, using an appropriate method.

Sharp Edges, weld spatter, cavities and deformations are to be removed.

The steel surface for Rust grades to be assessed.

Surface shall be cleaned by abrasive blast cleaning.

Salt deposition test shall be performed randomly after surface preparation and before apply of each coat of painting.

Value of acceptance 5 Microgram/cm². If the value exceeds acceptable limit, surface to be cleaned using high pressure water cleaning 34-70MPA.


Blasting:- The pressure should be at least 7kg per cm 2 P (100lbs per inchP2P) at

the nozzle. The size of Copper slag used for Blasting shall be 0.75 to 2.0 mm. Abrasives like copper slag should be used only one time, and should not

be contaminated with soil.


Painting:- Shall not apply paint when temperature falls below 10°C. Blast cleaned surface shall be coated with primer with in maximum 3-4

hours. If relative humidity is over 75% this should be reduced to 1-2 hours for better performance.

Thinner should be added only if the viscosity increases due to temperature

change during application.

All paint shall be stirred thoroughly prior to use. Stirring up will also become necessary repeatedly during application to prevent settling of Pigments.

All paint shall be stirred thoroughly prior to use. Stirring up will also become necessary repeatedly during application to prevent settling of Pigments.

Paint shall be applied only to dry, clean, adequately prepared surfaces

under favorable conditions and in accordance with the paint manufacturer’s instructions.


Curing time between two coats shall not be less than one night or as per paint

Min 10Nos reading of DFT shall be recorded for each 1M² area.

Total Nominal DFT Two coat system with total nominal DFT of 500-600 micron, 250 micron for each coat.


Post painting quality checks:- Painting should not be carried out during windy conditions. Blast cleaned surface shall be coated with primer with in maximum 3-4

hours. If relative humidity is over 75% this should be reduced to 1-2 hours for better performance.

Weather shelters should be made available to cover application equipment during mixing and application of material.

After given curing time, the area of interest for the checking of Adhesion test.

Adhesion Test:- It should be free from dust and oil. Make a ‘X’ cut with the short edge tool above the Area of interest and maintain the angle between the ‘X’ is 15 to 30. Then affix one inch width of adhesive tape over the cut and peel off the same immediately. If any paint stuck on adhesive tape it is recommended to re blast the area and re paint the primer.

Installation of Steel Pile Steel Pile Assembly:- 1371.6mm dia steel spools of appropriate grade and of designed thickness and

length of 12m shall be transported from Wel-spun pipe manufacturers Dahej assembly Yard.

Step 1:- Stacking of spools at stock yard.

Installation of Steel Pile (Contd.)

Step 2:- Placing on bed with 90T Goliath crane.

Step 3:- Fit up and SAW Welding at Fit up bed and SAW roller bed.


Step 4:- Welding of bearing stiffners for plug Concrete at fit up bed.

Step 5:- Lifting hook Welding at assembly bed after SAW welding.


Step 6:- Sand Blasting and painting. (Discussed earlier) Step 7:- Loading and transport by Dumb barge – This operation is done during high

tide.

Installation of Steel Pile (Contd.) Step 8:- Handling and Transfer from Dumb Barge to Jack up barge.


Step 9:- Positioning and fixing in guide.


Driving by DELMAG Hammer:- The crane will then lift the Delmag hammer and place it on the top of the pile. The

batter of the hammer will be matched with the batter of the pile with the help of spreader beam attached to it.

A removable projected frame fabricated and attached with the hammer frame to facilitate lifting in rack alignment.


The hammer is then placed on top of the steel pile.


Driving of the pile is commenced initially with the lowest and gradually increased to appropriate settings depending upon soil resistance.


The surveyor will all the time keep observation of the pile driving process and will intimate the barge engineer on or near to reaching the pile cut off level.

On completion of driving operation the surveyor will mark the cut off level and the excess top piece is removed by cutting with gas cutter.

Thank You!

An introduction to steel piles

Engineering