Folie 1

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IWM 2003 in Seattle, September 24 - 27IWM 2003 in Seattle, September 24 - 27

Folie 1

Main dimensions of trough:

width is 15 m (45 ft) for double tracklength is 1200 m (1400 yards)depth is 14 m (46 ft) to pass the river

Finished Trough "West" without Tracks

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Folie 2

Trough during installation of Micropiles TITAN and Foundation Plate.

2 Drill Rigs operate from a Bridge, which runs on rails on top of sheet pile wall

In FrontFoundation Plate without Reinforcement, poured under water

BehindSecond Foundation Plate with Reinforcement. Both Plates are fixed by Micropiles TITAN 103/51

Soil InvestigationThe job is at sea level; approx. 30 miles from coast. Structure of soil is typical for Western Part of the Netherlands.

Backfilled sandOrganic Veen with layers of soft clayMedium dense sand, Dutch cone resistance qc = 15 MPa from - 16 m (52 ft) to -34 m (112 ft)

Micropiles transfer the load to the layer of medium dense sand.

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Folie 3

Dutch standard CUR 2001-4 gives for estimation of ultimate skin friction

qs ~ qc100

qs = 150 kN/m²

This value is confirmed by Eurocode (EC 7), which gives for sand same figure.

10 MPa 15 MPa

- 14

Soil Investigation by CPT

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Folie 5

Exhumed Micropiles TITAN 103/51The grouted body was flushed clear and lifted out of the ground.The holes were backfilled with bentonite. Average diameter of grouted body was measured with 254 mm (10").

Exhumed Micropiles TITAN 103/51average diameter 254 mm (10")

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Folie 6

Neat grout = Portland cement, qualtity B25, unconfined compressive strength > 25 N/mm²

Filtercake = concentration of cement, arch effect, diaphragm

Interlocking shear bond by jet grouting effect

TITAN 103/51 centered in the micropile, equal cement stone cover, best shear bond

254 mm Ø

10“

254 mm Ø

10“

Exhumed Micropile TITAN 103/51

Structure of Grout body in medium dense sand below water table

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Folie 7

TECHNISCHE UNIVERSITÄT MÜNCHENINSTITUT FÜR BAUSTOFFE UND KONSTRUKTIONLEHRSTUHL FÜR MASSIVBAUProf. Schießl-Prof. Zilch

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crack width ( mm)

Measuring Crack Width of Exhumed Micropiles TITAN 103/51The excavated micropiles were tested concerning micro cracks at the University of Munich. Up to a load of 1200 kN (540 KIPS) all measured cracks were below 0,01 mm. No cracks in longitudinal direction were observed. Result: Simple corrosion protection by cement cover of min. 50 mm (2") is sufficient for permanent micropiles TITAN 103/51 on tension.

Testing Exhumed Micropiles TITAN 103/51 with respect to micro cracks

Furthermore the area of the couplings was investigated in the tension test. The play for alternating loads on tension and compression was measured below the 0,01 mm acc. to DIN 1045 for connections of reinforced steel bars.

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Folie 8

FDR,0 = Pile Force in Tendon

FKV,0 = Pile Force in Grout Body

Investigation of Load Transfer and Load Distribution in Micropiles TITANTell tales (extensometers) were installed in the test micropiles TITAN 103/51 to monitor load transfer from micropile to sand.Result: Up to gravity point of bonded length approx. 2/3 of the load is already transferred to the ground.

Load Transfer and Load Distribution in Micropiles TITAN 30/11

Monitoring the distribution of the load transfer to the ground by extensometers, installed inside the hollow TITAN pile.

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Folie 9

On pile head a min. length e.g. 408 mm for TITAN 30/11 is necessary to activate the full bearing capacity of the grout body. The load transfer from steel tendon to grout body stops, when strain rate in interface is the same.

The load transfer by shear bond from steel tendon to grout body causes circular tension forces in cement grout body.

To avoid very dangerous axial cracks in grout body, caused by circular tension forces, a minimum cement cover and a smooth HD-PE tube is recommended for pile head.

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Calculation Model for Circular Forces R

caused by Shear Bond e.g. TITAN 30/11

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Folie 10

Installation sequence

14 TITAN 103/51 micro piles are installed per day, each 20 m long. This is achieved by 2 teams each 3 men and 2 hydraulic drill rigs. The rigs are positioned on a bridge, 5 m above the water level. This bridge moves on

rails, being supported by the sheet pile walls.

This rigid support enables precise drilling operations in comparison to a floating pontoon.

This bridge is also used for tension testing, the sheet piles are used as reaction piles.

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Folie 11

A small excavator, equipped with a hydraulic manipulator, handles the 3 m long bars with 130 kg (290 lbs.) weight, and positions it onto the rig.

Important is a standpipe 219 mm diam. (9”), 21 m long (22 yards) with a flushing collector welded to it’s top.

This standpipe is pressed 2 m (2yards) into the soft ground. The TITAN micro pile is inserted and drilled through that standpipe. The return flow of flushing is being pumped from the top collector and enables excellent control over the drilling process. Return flushing is going into a de-sanding unit and the remains are collected in container, cladded with a PVC foil.

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Folie 12

Mini excavator withhydraulic manipulator lift the TITAN piles,each 130 kg weight

hinged coupling nut for seperation ofthe TITAN piles.The standard coupling nuts are fixedwith Hilti Hit C 100 glue.

standpipe 219 mm diam., 21 m long long with grout collector vibrated 2 m deep into the soil

This standpipe prevents an uncontrolled underwater spill and pollution of the water with the cement flushing. It also acts as directionally stabilizing guide for the free drill length, in water and air of 20 m (22 yards).

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Prepared material for micropile TITAN 103/51

Quality control sheet of Micropiles TITAN

Folie 13

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Folie 14

Screwing the Drill Bit

Inserting the

Micropile in

Standpipe

Handling Advantages with Micropiles TITAN in this applicaton:

- Positioning pile head to the desired precise level- Nearly no spill of grout close to pile head, which reduces static effective thickness of slab.

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Folie 15

Hinged Coupling Nut

Standpipe 219 mm Ø with collector for return flushing

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Steps of installation for Micropiles TITAN 103/7820 m below water table, to prevent heaving of concrete slab

Collector for used

cement flushing

cleaning the casing

before pulling

casing

Rope

Diver

Folie 16

Sheet pile wall

Folie 1

Documents

Transcript of Folie 1