Technical Assessment 3/07-526

Foundation system

FONDAPIEU Holder: JEAN MARIE RENOVATION

2, Rue Croquoison F-80420 FLIXECOURT Tel.: 03 22 39 28 73 Fax: 03 22 52 30 93 Internet: www.fondapieu.com E-mail: denis.jmarie@wanadoo.fr

Commission in charge of Issuing Technical Assessments (Decree of December 2, 1969)

Specialised Group no. 3 Structures, floors and other structural components

Presented for registration on September 26, 2007

Secretariat of the Technical Assessment Commission CSTB, 84 Avenue Jean Jaurès, Champs sur Marne, F-77447 Marne la Vallée Cedex 2 Tel.: 01 64 68 82 82 - Fax: 01 60 05 70 37 - Internet: www.cstb.fr

The Technical Assessments are published by the Technical Assessment Secretariat, provided by CSTB. The authenticated versions are available free of charge on CSTB’s Internet site (http://www.cstb.fr)

CSTB 2007

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Specialised Group no. 3 of the Commission in Charge of Issuing Technical Assessments on June 25, 2007, examined the "Fondapieu" foundation pile system, marketed by Société Jean Marie Renovation. Concerning this system, it formulated the following Technical Assessment. This Assessment was formulated for applications in European France.

1. General description

1.1 Brief description Cast aluminium piles, consisting of helical and cuneiform shaped elements, assembled by high strength aluminium alloy studs. When struck by a hammer, they screw by themselves into the ground, thanks to their special shape.

The elements measure 0.24, 0.50 or 1.00 m long with section of 70 mm or 105 mm, circumscribed diameter. The elements can be solid or hollow if they are to be injected with a grout. Special cylindrical shaped elements exist. They are used at the head of the piles undergoing an eccentric moment or are used to cross through layers of swelling clays. They can be inserted between two conventional elements.

The connections to the structure use devices adapted to the Fondapieu system.

2. ASSESSMENT

2.1 Accepted field of application

The Assessment has been formulated for the insertion of piles down to depths equal to or less than 6 m and exceptionally, down to 8 m in the case of use of smooth elements to cross through a layer of swelling clays. The applications considered are the construction of foundations of new buildings or extensions, and partial or total underpinning of the load from existing buildings. These foundations apply to light structures (for example: individual homes). The load limits result from the application of the approved sizing rules, defined in the Technical Specification Book.

The working of the piles under bending stress is not covered by this Assessment. The strain at the head of the pile is reduced to a normal (perpendicular) centred force (compressive or tensile).

Use in earthquake zone is not covered in this Assessment.

2.2 Assessment of the system

2.21 Compliance with the laws and regulations in force and other qualities of suitability for the application

Stability

The structures are normally stable as long as the load assumed by the piles remains limited to the permissible load calculated under the conditions indicated in the Technical Specification Book and as long as a tension test (or a compression test in the case of an active linking) is carried out on all the Fondapieu piles inserted according to the guidelines contained in the Technical File.

Safety of persons

For the system itself, safety is normally provided. The insertion shall be performed by technicians qualified and trained by the holder, using the equipment recommended by that holder.

2.22 Durability - servicing The aluminium alloy with which the Fondapieu pile elements are manufactured come under the non-oxidising category. However, installation in soils with substantial chlorine content should be avoided.

The aluminium assembly studs of the pile elements are protected from aqueous corrosion by a hard anodising protection.

Risk of galvanic corrosion is negligible because the difference of potentials between the aluminium alloys used for the Fondapieu pile elements and those for the assembly studs is low enough.

2.23 Manufacture The helical Fondapieu piles are manufactured by a subcontracting foundry, the quality assurance manual of which meets the requirements of the Ministry of the Interior.

The subcontracting firm which machines the helical Fondapieu piles, the smooth Fondapieu piles and the studs is specialised in precision machining. It also subjects the pieces to quality assurance operations, inspection of the assembly and of the palletising.

2.24 Insertion The Fondapieu piles are inserted by contracting firms approved by the holder. These firms’ personnel shall have followed a mandatory course of qualification for the installation of the system, conducted by the holder.

Technical assistance is provided by the holder for the implementation and by the Rabaud company for the installation equipment.

2.3 Technical Specification Book

2.31 Design specifications The piles shall be sized based on a soil survey in compliance with Standard NF P 94500 and including at least two tests by ground bearing pressure meter and two tests by penetrometer.

The structural sizing and calculation are performed by the Bureau d’Etudes Verrier Ingénierie (engineering firm), the holder’s partner, of by an engineering firm under the responsibility of Freyssinet France.

The execution study and design provided by that engineering firm is verified and approved by the approved installation-contracting firm.

The overall approach to sizing comprises the calculation of the strains at the Ultimate Limit State (ULS) and at the Working Limit State (WLS), the initial assessment of the type and number of piles, the calculation of the vertical load on each pile, the corroboration of these piles and of the connections to the structures. The positioning and the size of the piles are then readjusted to satisfy all the criteria.

The Fondapieu piles work in the axial direction only. Their working under bending stress is not covered by this Assessment. However, their sizing must always take into account the eccentric moments due to the installation tolerances, defined in Paragraph 2.33.

Whenever the Fondapieu piles cross down through substantial distances of inconsistent earths, their resistance to buckling must be checked.

2.311 Permissible load for the piles: Qt

The permissible load Qt is calculated, considering the following:

- For the piles working under compression stress: the resistance of the section of the elements,

- For the piles working under tension stress: the minimal magnitude between the strength of the studs and the strength of the section of the elements.

The strength of the studs is given in Paragraph 6.1 of the Technical File.

The strength of the section is obtained by applying the bearing capacity of the cast aluminium (that is, 75 MPa for the helical Fondapieu piles and 110 MPa for the smooth Fondapieu piles) to the total section of the pile.

The helical elements are sizing elements in terms of section resistance. That section is 16.1 cm² for the FD60s and 35.1 cm² for the FD90s. In this way, the following permissible loads are obtained:

- for the type FD60 piles: 121 kN,

- for the type FD90 piles: 263 kN.

2.312 Bearing capacity as a function of the soil or ground: Ql

The calculation method described below must be validated by sizing tests.

The bearing capacity is calculated assuming a peak resistance zero and a lateral friction equivalent to that of a metal pile, as described in DTU 13.2.

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The surface Sf against which the friction is applied, is equal to the surface of the cylinder defined by the circumscribed diameter of the Fondapieu pile. The table below contains the figures to be used.

Table no. 1

Sf (m²/ml)

FD60 0.221

FD90 0.326

FDL60 0.188

FDL80 0.251

The bearing capacity is then deduced from the following expression:

( )∑=i

ifi,sl hS.qQ

In which: hi: the depth of layer i

qs,i: the unit lateral friction for the ground of layer i.

The last meter of Fondapieu pile inserted is not taken into account in the calculation of the bearing capacity.

In case of foundations subjected to a negative friction, the bearing capacity Ql is calculated, assuming that the lateral friction is zero above the neutral point (point above which the negative friction affects the element) determined for an element supposed to be isolated.

2.313 Load assumed by the pile

QWLS = min (0.5. Ql; 0.5.Qt)

QULS = min (0.75.Ql; 0.75.Qt)

2.314 Verification tests

The load to be validated during the tests, on each pile, is determined by the engineering firm. It is equal to 1.2 times the load at the working limit state (WLS) for the tests under tension and 1.5 times the WLS load for the tests under compression.

2.315 Layout

The minimal spacing between Fondapieu piles is 0.80 m between two 60 diameter piles, 1.30 m between two 90 diameter piles and 1 m between one 60 diameter pile and one 90 diameter pile.

The maximal length of the smooth cylindrical piles intended for the clayey layer is 2 m.

Injectable piles shall be used in any decompressed ground.

The piles shall be inserted:

- Either within the foundation’s axis, plumb with the vertical loads,

- Or in pairs on either side of the vertical load so as to centre the bearing force,

- Or under an alignment sleeper, making sure that the piles work only under tensile stress or compressive stress.

2.32 Manufacturing guidelines The self-inspection carried out at the foundry and at the machining firm shall check the quality of the material of the cast pile and also the anticorrosion treatment of the studs as well as the dimensional inspection of all the parts.

2.33 Installation guidelines At the beginning of each project it is necessary to mark out the positions of any external conduits in the zone where the piles are to be laid out.

The tolerances accepted during the insertion are:

- Pile slope: ± 2°,

- Distance to the wall or other element of the structure to which the pile is linked: ± 3 cm,

- Position (not counting the distance to the wall above): ± 10 cm.

A tension test (or a compression test in the case of an active link) shall be carried out on each pile installed according to the method described in the Technical File in Paragraph 5.32 14/.

In the case of injectable piles, the maximal injection pressure is 12 bars.

Conclusions

Overall evaluation The use of the Fondapieu pile foundation system in the accepted application field is favourably assessed.

Validity Until June 30, 2009

For Specialised Group no. 3 The Chairman

J.P BRIN

3. Complementary remarks from the Specialised Group

In case of unforeseen situations (presence of blocks not noted during the soil survey, preventing the driving of the piles, for example), the solutions do not differ from those adopted usually for the conventional systems of deep foundations.

It must be kept in mind that sizing tests shall be carried out to make sure that the calculation and design model indicated in this Assessment guarantees a safety coefficient at least equal to the one defined in DTU 13.2. This remark is valid for all types of soils, particularly powdery soils and for all types of piles, including injected piles.

The Rapporteur of Specialised Group no. 3

M. CHENAF

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Technical File prepared by the requester

A. Description

1. Intended use and general description

The Fondapieux piles are patented piles, cuneiform and helical, of cast aluminium, assembled by high strength anodised aluminium studs as the penetration progresses into the ground.

These elements are solid, or they are hollow if they are intended to be injected with a grout. They come in two diameters (70 and 105 mm) and are available in the following dimensions: 240, 500 and 1000 mm. The geometry of the Fondapieu pile allows it to be screwed by itself into the ground (without preliminary hole) under the effect of the stroke of a hammer, without vibration, while compressing the surrounding soil. On the core, the three fins protrude considerably and, in this way, provide a good friction resistance as well as an effective mechanical fixing.

The Fondapieu piles are installed down to 6 m deep. The helical elements can be combined with cylindrical elements (2 m maximum), the maximal depth of the combination then being able to reach 8 m.

The Fondapieu piles are used in the following cases:

- Foundations for new buildings and building extensions,

- Reinforcement of foundations of recent and old buildings (assumption of 30 to 50% of the load),

- Assumption of 100% of the load of existing buildings located on clayey soils, containing shrinkage-swelling hazards and on badly damaged buildings where the engineering firm recommends the assumption of the full load.

The Fondapieu piles can be installed in locations, which are narrow or where access is difficult, thanks to the installation with the aid of manually operated portable hammers.

2. Materials

The materials incorporated are:

- Aluminium alloys for the manufacture of the piles, of the studs and of the buffer caps,

- Injection grout for the injected Fondapieu piles.

2.1 Aluminium alloys

• The aluminium alloys used for the helical Fondapieu piles and for the buffer caps is type 42200 according to Standard NF EN 1676 (chemical designation: AlSi7Mg06Y20 1

st melting). Due

to its chemical composition, it is recognised as being in the non-oxidising class. It provides an oxidation resistance, rated ¾ under atmospheric effect: saline and seaside air. Its predisposition for casting provide it with an oxidation resistance of 4/4 in terms of casting predisposition, thus preventing shrinkage cavities and cracks. Its permissible bearing capacity is 75 MPa.

• The aluminium alloy used for the smooth cylindrical Fondapieu piles is type 5083 according to Standard NF EN 573 (chemical designation: AlMg4.5Mn07). Its permissible bearing capacity is 110 MPa.

• The aluminium alloy used for the studs is type 7049A according to Standard NF EN 573-1 (chemical designation: AlZn8MgCu). It is one of the high strength aluminium alloys. Its bearing capacity is 530 MPa.

2.2 Injection grout The injection grout is made by adding water to the Superstresscem hydraulic binder in bags of 25 kg from the HOLCIM company and to the associated packets of admixture or any other equivalent ultra-fine hydraulic binder suitable for making injection grouts. On the average, one bag of 25 kg is used for 1 m of Fondapieu pile.

3. Elements

3.1 Fondapieu pile elements The Fondapieu pile elements are cuneiform and helical and are tapped at each of their ends (see Figure 2). The complete line is shown in Table 1 and in Figure 1 in Appendix.

Two diameters are available:

- the FD60 fits within a 70 mm diameter circle, and each of the 3 facets measures 60 mm and the pitch is 24.8 cm long,

- the FD90 fits within a 105 mm diameter circle, each of the 3 facets measures 90 mm and the pitch is 46.5 cm long.

For each diameter there are three versions:

- The « conventional » Fondapieu pile: the elements are solid,

- The « injectable » Fondapieu pile: the elements contain a central vertical hole called the « injection bore », diameter 10 mm and horizontal holes, called « branches », diameter 8 mm for the FD90s and 6 mm for the FD60s, positioned in a star and spaced 25 cm vertically (that is 3 times 3 holes for an element 1 m long).

- The « smooth » Fondapieu pile: the elements are smooth cylindrical to reduce the negative forces due to clayey soils containing shrinkage-swelling hazards. They can also be used on the first meters of a pile that is eccentric with relation to the load to be assumed. These smooth Fondapieu piles also come in injectable version (injection bore only).

In the first two versions, there are special elements, which contain a monobloc toe. These pierce the soil well and enable the centring of the alignment when driving the Fondapieu pile. In the injectable version, the toe is hollow to enable the formation of a bulb at the head of the pile. It also has, at its extremity, an aluminium « plug ».

This is simply installed at the extremity of the toe and has a diameter equivalent to the injection bore so it can be forcibly fitted in. This makes it possible to prevent the materials constituting the substrate from penetrating the injection bore at the moment when the Fondapieu pile is being inserted.

In injection phase, whenever the pressure is weak, the pile remains in place and the grout comes out through the branches (with the injection bore not obstructed).

On the other hand, whenever the pressure is high, the plug shifts a little bit within the substrate to let the grout pass through and, in this way, forms a more or less large bulb at the bottom part. Then the grout comes out through the branches.

3.2 Studs The « Fondapieu piles special » studs are patented and machined from high strength aluminium extruded bars. They are 13 cm long, diameter 20 mm, for the FD60 type elements or 26 mm, for the FD90 type elements (see Figures 3 and 5).

Their pitch is 12 mm and they contain 3 threads which, to complement the accuracy of the tapping of the elements of the Fondapieu piles, enable a perfect alignment of the Fondapieu piles during assembly.

They are lathe turned at one extremity to compensate for the taper of the Fondapieu pile tapping grooves.

The studs are subjected to a treatment of protection by hard anodising to improve their anticorrosion performances.

For the « injectable » Fondapieu piles, the studs are drilled (φ 5 mm for

the φ 20 mm studs and φ 8 mm for the φ 26 mm studs).

3.3 Buffer caps The buffer caps were especially designed and patented for the installation of the Fondapieu piles. They are positioned between the hammer and the head of the Fondapieu pile element installed. They are called « disposable buffer caps » because their service life depends on the hardness of the ground and the striking tool.

They are of aluminium for their lightness to be easily manipulated by the operator but above all to transmit the tool’s integral stroke.

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Inside, they contain indentations, shaped for the Fondapieu 60 and 90 piles, a recess for the studs and a steel insert where the Fondapieu is struck in order to not to bulge and round the trim face of the Fondapieu pile.

On the outside:

- At the upper part: they are star or cylindrical shape to adapt them to the various striking tools (see Figure 4).

- At the central part: they all have the same indentation, designed to receive the ratchet spanner, also patented.

There are 3 buffer cap models (power hammer model, Rhino model and independently operating pile inserter model), each model has the indentation of the FD 60 and FD 90.

4. Manufacture

4.1 Fondapieu pile manufacture

4.11 Casting The Fondapieu pile elements are manufactured in the foundry of Société Industrielle de Conty (SIC) in Conty (80) according to that company’s Quality Assurance Plan. The pieces are cast in vertical moulds of self-hardening silica sand. This casting method provides optimal feed of the piece during the casting and minimal strains (minimal shrinkage cavities and cracks) during cooling (shrinkage).

The piles are then cut to length with a mechanical saw (-0/+3mm).

According to the specifications of the foundry’s Quality Assurance Manual, for each batch of ingots melted, a test specimen for each tonne of material received is cast separately and stored.

A destructive quality assurance operation on the piles is carried out every 100 piles for the inspection of the material’s soundness.

The batch reference (casting number) appears on the Fondapieu pile delivery slip so that the pieces can be traced.

The buffer caps are also cast in this foundry. Their service life is for 300 to 600 linear meters of Fondapieu piles driven, according to the nature of the ground in which they have been used.

4.12 Machining Located next to La Roche sur Yon (85), Robin Technologie is the firm that machines the Fondapieu piles and bores the injectable Fondapieux piles. These production steps of the Fondapieu piles are carried out according to the specifications of the company’s Quality Manual (tolerances: tapping length: +3/-0mm and distance between branches: +5/-5mm).

The front hole of the pile’s tapping is made in a single operation on a machine that aligns the pile’s axis with the machine’s axis, and the tool’s shape guarantees the perpendicularity between the pile’s face and the hole’s axis. The boring depth is set on a tool. The jig indexes the tapping inlet with relation to the toes of the pile, and this makes it possible to align the three turns at the positioning.

4.2 Manufacture of the studs Robin Technologie also machines the studs according to the specifications of its Quality Manual. The studs receive the protection by hard anodising by a subcontracting firm. Quality

control operations (thickness 20 ± 5µm) are conducted by Robin Technologie.

4.3 Assembly Each Fondapieu pile is sold with its stud installed. The stud is protected by a protective net for transportation. Robin Technologie is responsible for this assembly, for its quality control operations and for the palletising of the finished pieces.

The lathe turning on a stud end is positioned in the upper part of the pile, and in this way, the stud’s end is in contact with the bottom of the hole. This makes it possible to reduce the mechanical stresses on the latter during assembly of the upper part.

4.4 Delivery to the customer The shipment of all the Fondapieu piles to the exclusive approved installers leaves from Robin Technologie. For

traceability reasons, the pouring number of the aluminium alloy used for the production of the piles appears on the delivery slip.

5. Installation

5.1 Technical assistance Only the firms exclusively approved by JMR install the Fondapieu piles. France is covered exclusively by a network of 7 branches of Société Freyssinet France, with the exception of the following 3 « départements » (districts): Tarn, Tarn et Garonne, and Haute Garonne, where the exclusivity is shared with another firm.

Abroad, Fondapieu has partners in Benelux, in Germany, in Austria and in Great Britain.

Installing Fondapieu piles requires a qualification that the personnel obtain after the practical and theoretical mandatory training course, conducted by JMR, which then provides technical assistance in case of installation problems.

The Rabaud company services all the tooling and equipment in the catalog.

5.2 Equipment The equipment necessary for installation is as follows:

- 1 striking hammer (electric, pneumatic or hydraulic),

- 1 driving buffer cap,

- 1 two-axis spirit level for installing the first Fondapieu pile,

- 1 ratchet spanner,

- 1 anti-rotation disk and the corresponding universal joint,

- 1 test pedestal and its positioning mechanism,

- 1 computer for validating the « test » ticket.

JMR has created a partnership with the RABAUD company that provides the firms approved by JMR only, facilitated by the partnership, with a catalog containing all the machines and tools necessary for installing the Fondapieu piles.

Concerning the striking hammers, the pneumatic or electric systems are not in the catalog. JMR and Rabaud have worked together to create the Independently Operating Pile Inserted (IOPI), which is a striking tool, hydraulically powered, and especially designed for this work (see Figure 8).

As to the injectable piles, the injection machines are portable micro- actuators.

The injectors were designed by JMR. They are made by Société Plastech in Courtemanche (80). They are made of polyamide plastic, with 35% glass fibre filler. They are fitted with a pull to obstruct the injection bore at any time. There are injectors for the FDI 60s and for the FDI 90s.

To connect the injectors to the ¾ valve usually installed at the output of the injection machines, JMR also provides a black plastic « gripper », also made by Société Plastech.

Unlike the gripper that can be washed for later use, the injectors use it only once.

The Rabaud catalog also contains the kits to hold the wear parts and the calibration references of the pressure gauges of the testing positioning mechanisms with calibration certificate.

5.3 Product guidelines and installation

5.31 Preliminary steps Before actually installing a Fondapieu pile, it is indispensable that the following operations be carried out:

- Identifying and listing any dislocations on the site,

- Preparing a list of actions for correcting and preventing problems,

- Preparing, by the execution engineering firm, a calculation and design note, corroborating the Fondapieu piles on the structure (see Paragraph 6)

. The working study and design will need to be verified and approved by the company approved for the installation of the Fondapieu piles,

- Then, according to the case, approval by the chartered inspection firm or by the expert, or of the two bodies concerning the guidelines for loads to be assumed and positions of the Fondapieu piles.

Once the Fondapieu pile layout drawing is acquired, the first thing to check is the positions of any outside conduits.

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5.32 Installation steps 1/ Check the layout drawing and the information given by the engineering firm with regard to the real nature of the site. In front of each Fondapieu pile position, place the number of Fondapieu pile elements planned, in the order of their installation in the case of combination. This makes it possible to set down on the drawing the real number of Fondapieu piles being installed.

2/ Preparation of the ground or of the trench bottom

3/ Driving down the bore starter rod to align the first pile and check its verticality with the two-axis spirit level.

4/ Position the first Fondapieu pile

5/ Install the drive buffer cap on the Fondapieu pile

6/ Set the power hammer on the buffer cap

7/ Driving under the power hammer’s weight only and checking the verticality of the first Fondapieu pile (it is important to drive the first Fondapieu pile element as plumb as possible because the next element follows the same alignment). A maximal slope variation of 2° is permissible.

8/ Smoothly boost the rotation with the aid of the ratchet spanner, which was especially designed to adapt to all the buffer caps, but particularly to absorb 80% of the vibrations transmitted from the power hammer to the buffer cap (see Figure 6).

9/ Once the first Fondapieu pile has been driven in, remove the power hammer and the buffer cap.

10/ Position the second pile by screwing by hand.

11/ Reposition the buffer cap, equipped with the ratchet spanner and tighten (with the aid of that spanner) the second FD on the first FD. Since the pitch is 12, the tightening is very short. This is normally done by placing one hand on the buffer cap and the other on the handle. The tapping precision is calculated so that the fins of the upper Fondapieu pile stop at approximately five millimetres set back from the fins of the lower Fondapieu pile. Even if the two Fondapieu piles are not perfectly aligned above the ground, their tightening is finalised as soon as they penetrate the ground.

12/ Set the power hammer back on the buffer cap and begin the operation again down to the desired depth.

Just as with the bore starter rod, it is possible to run into obstacles in the earth, such as large stones. However, beginning with the 2

nd meter, the Fondapieu pile is guided by the alignment

of the first element.

Consequently, the toe of the first Fondapieu pile pushes on the extremities of the small stones without deviating from its trajectory. Any calcareous stones end up breaking because of the vibrations.

For any large unbreakable stones, according to the depth, there are a number of possibilities:

- From -1 m to -3 m: remove the 3 Fondapieu piles using the tester and its upward extension. The insertion can then be continued at less than 10 cm from the first location.

- From -3m to -5m: o 1

st solution: the Fondapieu piles are not embedded in the

foundation by an individual concrete footing but they are installed in a steel reinforced concrete sleeper. Then the pile is tested, and, according to the value obtained, the inadequate load is compensated for by adding elements on the Fondapieu piles to the left and/or to the right. The engineering firm is then notified and the values are corrected on the drawing.

o 2nd

solution: it is an individual footing. It is tested and the engineering firm is contacted, the engineering firm then takes the decision with regard to the inadequate tonnage value missing and according to the existing foundations. If it is possible to pass the additional load onto the individual concrete footings of the Fondapieu piles located nearby, another Fondapieu pile is added as a pair or create a sleeper at that location.

o 3rd solution: if it is an FD 60, it is to be removed and

replaced by an FD 90 to obtain the desired value. o 4

th solution: if it is an FD 60, it is replaced by an FDI 60

and if it is an FD 90, it is replaced by an FDI 90.

Whenever the last Fondapieu pile has been installed and its altimetric level is wrong (because the pile cannot go deeper) it is quite possible to take a rotary cutter with a cutting disk suitable for the aluminium and to cut off part of the Fondapieu pile as desired. It is then possible to drill and tap the cast aluminium in place using the cutting, drilling and tapping kit proposed by JMR.

13/ Once the necessary number of Fondapieu piles is inserted, the tension test is carried out (or the compression test with the patented brackets in the case of an “active” link, Paragraph 5.33b). The test equipment is guaranteed to withstand 20 tonnes even though it is light, easy and quick to bring into operation. It is carefully positioned on wood shims, with large enough dimensions to prevent their being pressed into the ground.

14/ Tension test (or compression test)

Remark: The test method described below concerns the tension tests but is directly transposable to the compression tests that are carried out in the case of an « active » link (see Paragraph 5.33b).

Checking the alignment of the positioning mechanism with the Fondapieu pile: installation of anti-rotation disk without the two steel rods and application of a slight tension. If the anti-rotation disk comes unscrewed while shifting laterally a few millimetres, the alignment of the Fondapieu pile in the ground is slightly different from the alignment of the positioning mechanism on the tester and it is necessary to readjust at the wood shims. Repeat the operation until the disk does not become unscrewed but does not shift anymore. Then install the two rods to block the rotation and start the tension test.

Once the tester is installed, the pressure in the positioning mechanism can be obtained:

- either with the aid of a manual hydraulic pump,

- or automatically, with the chassis of the independently operating pile inserter (IOPI).

In both cases, the procedure is the same:

- Switching on the positioning mechanism and gradually raising it in time increments of a few seconds, for each tonne reached, until the desired tonnage.

- Time increment of 2 to 3 min when the desired tonnage is reached: o If the tension does not vary, the test is confirmed and the

pressure gauge value is noted on the drawing. o If the tension drops, either the wood shims are driven down

and it is then necessary to increase the bearing capacity by broadening the surface of the wood shims on the ground, or the Fondapieu pile rises and it is then necessary to take down the tester unit and add an additional meter of Fondapieu pile, and then begin the tension test again.

Beyond 6 m of helical Fondapieu piles, it is possible to add 1 to 2 m of smooth Fondapieu piles. If the recalculated value is not reached, the engineering firm must be notified.

The use of the IOPI chassis makes it possible to automate the test and to print a test ticket upon which the following information appears: o Nature of the test: Compression or Tension, o Jobsite address, o Date and time, o Fondapieu no., o FD60 or FD90 type, injectable or not, o Quantity of smooth Fondapieu piles, o Depth installed, o Tonnage requested, o Tonnage validated.

Automatically, the positioning mechanism stops for a certain time at each tonnage and for a time three times longer at the desired tonnage (minimal settable time 30 seconds). If the variation of the value is less than 5% at the end of the time provided, the test ticket is printed. Otherwise, the ticket is not printed and it is then necessary to take out the tester and add 0.50 or 1 m of additional Fondapieu pile.

15/ Driving the Fondapieu pile 15 to 20 cm more to install it at a level lower than that of the tension test. The Fondapieu pile then becomes operational.

For the injectable Fondapieu piles, the same operations are performed from 1 to 15. So we have a test value before injection, then:

16/ Installation of disposable injectors and injection of grout

In normal use, the injection is by gravity. The machine pump is set to 6 bars. The grout is injected in “intermittent bursts”. This applies to all decompressed soils. In the case of fragmented chalks, the machine is set to 10 or 12 bars maximum because, beyond that, there is a risk of segregation of the grout.

When the injection is terminated, the injector’s lever is pushed to close the injection bore.

17/ Tension test eight days after the injection according to the procedure described in point 14. This test is carried out on at least one Fondapieu test pile per jobsite and the number of tests shall not be less than 1 for 20 piles.

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5.33 Linking to the structure Two linking procedures can be considered:

- So-called « passive » linking: the Fondapieu pile is driven, given a tension test and embedded in the structure by various steel reinforcement methods.

- So-called « active » linking: the Fondapieu pile is driven, equipped with a suitable bracket, then placed under compression at the tonnage requested by the engineering firm, using a positioning mechanism and, after blocking the bracket, the Fondapieu pile immediately assumes the requested load.

a) So-called « Passive » linking

The Fondapieu piles can be located in 3 configurations:

1°) Fondapieu piles within the axis of the foundation (New construction and extension): they are centred and are directly plumb with the vertical loads.

2°) Fondapieu piles on both sides of the foundations (existing heavy structure with 100% of the load assumption): they are laid out in pairs so as to centre the bearing force under the façades. Then a cross-member is created.

3°) Fondapieu piles on a single side of the foundations under an alignment sleeper, making sure that the piles are working only under tension or under compression.

In every case, the Fondapieu pile shall be embedded in the concrete at least 35 cm to block its rotation.

The permissible tolerance on these distances is 3 cm.

When the foundation footings protrude more than 8.5 cm for the FD60s and 10 cm for the FD90s, it is recommended that a core be taken.

For the 3 categories, the most currently utilised link is implemented on sleepers. In this case, the bracing plates are installed at the head of the Fondapieu piles, blocked with an aluminium nut on the studs (see Figure 7). They are then linked to the joists, constituting the steel reinforcement.

JMR also proposes methods suitable to making individual footings and links to a concrete footing.

In every case, the sizing of the link is designed by the engineering firm and validated by the chartered firm.

b) So-called « Active » link

Various brackets have been designed and patented by JMR to respond to the most common types of dislocation.

Most of these brackets were designed to bring the Fondapieu piles immediately under compression. This implies its effective load.

These brackets can be used for concrete slabs, sleepers and footings and for masonry of all types.

Methodology of bringing the brackets under compression. 1. On the Fondapieu pile, positioning the supporting bracket,

the bearing bracket or the concrete slab substrate. 2. Installing the top bracing plate of the Fondapieu pile. 3. Installing the positioning mechanism. 4. Installing the star stop and the Arteon ties with quick

fastener. 5. Bringing the positioning mechanism under light pressure. 6. Adjusting the wheel of the star stop against the masonry to

keep a plumb alignment. 7. Bringing the positioning mechanism under pressure until it

reaches the desired tonnage. 8. Printing the test ticket. 9. Tightening the 2 nuts at the top bracing plate of the

Fondapieu pile. 10. Removing the positioning mechanism, the star stop and the

three Arteon ties. 11. Pouring the concrete individual footing.

The section of the concrete individual footings is somewhat larger in height (50 cm instead of 40 cm) so as to completely incorporate the support bracket or the bearing bracket.

6. Sizing

6.1 Corroboration of the studs The assembly of the studs to the Fondapieu pile elements has been tested experimentally under tension. For the two

geometries (stud φ 20 mm on FD60 and φ 26 mm on FD90), the break takes place by tensile stress on the stud, while the

threading and the tapping remain intact. The aluminium alloy with which the studs are made has a bearing capacity of 530 MPa, so their guaranteed tensile strength is as follows:

Solid stud of 20 mm Maximal tensile strength: 9 480 daN

Hollow stud of 20 mm Maximal tensile strength: 8 450 daN

Solid stud of 26 mm Maximal tensile strength: 18 500 daN

Hollow stud of 26 mm Maximal tensile strength: 15 860 daN

6.2 Soil survey Before starting the works of reinforcement by Fondapieu piles, the Developer or the approved contracting firm will need to have had the soil surveyed by a competent body.

This soil survey will need to include, at least, the following tests or surveys:

- Appropriate stripping of the foundation, - 2 pressiometric tests, - 2 tests with the penetrometer.

This soil survey is to be transmitted to the execution engineering firm for the calculation and design of the reinforcement.

6.3 General method of design and corroboration of the use of the Fondapieu pile method on a structure

1/ Determine the vertical loads at the base of the footing under the combinations of strains, weighted by the increase coefficients specified

in the BAEL* 91, revision* 99 (Appendix D).

2/ Calculate and design the bearing capacity of the Fondapieu piles starting with the limit load Qs due to the friction of the ground on the lateral surface of the Fondapieu pile such that:

Qs = qs As

with qs = lateral unit limit friction, determined from the curves in DTU** 13.2 for a metal pile, and validated by the sizing tests.

The Fondapieu piles are installed without bore drilling and, because of this, they increase the soil creep pressure. The friction surface considered is the surface of the circumscribed perimeter.

3/ Corroborate the internal stability of each of the elements and the general stability of the foundation system.

In the case of category 3 installation (Paragraph 5.33a), the study and design of the general stability will entail corroborating the building of a system working under tension - compression, linking the Fondapieu piles by sleepers which work either under torsion or under bending.

The ratio between the number of Fondapieu piles under tension and the number of Fondapieu piles under compression, as well as the dimensions of the sleepers and their steel reinforcement are to be

determined by an RDM*** study. The “tie” Fondapieu piles can have a slope up to 15° from the vertical.

An initial calculation is carried out under the permanent loads G with deferred moduluses of the concrete and of the ground in place.

A second calculation is carried out for the live loads Q with the instantaneous moduluses of the concrete and of the ground in place.

The calculation combinations are as follows:

G + Σφi Qi at WLS

and 1.35xG + 1.50 x Σφi Qi at ULS

The calculation note corroborating the Fondapieu piles on the structure furnished by the execution engineering firm includes, as a minimum: - The calculation of the vertical loads at the foundation level, - The layouts of the Fondapieu piles, - The loads applied on each Fondapieu pile, - The type and the length of each Fondapieu pile, - The corroboration of the overall stability of the structure, - The corroboration locally at each connection of the Fondapieu

piles to the existing structure (individual concrete footing, short bracket, etc.),

- The corroboration of the strains in each Fondapieu pile for category 3 (bending + compression). Each connection of a category 3 Fondapieu pile shall be studied and designed as an individual case, and shall be corroborated by a calculation of the strength of the materials.

* BAEL – Béton Armé aux Etats Limites (Reinforced Concrete at Limit States)

** DTU – Documents Techniques Unifiés (Unified Codes of Practice)

*** RDM – Réception et Décompte des Modules (Acceptance Inspection and Quantification of Modules)

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JMR is a partnership with the independent Engineering Firm, Verrier Ingénierie at Villers-Bocage (80). The Fondapieu piles are sized by this engineering firm of by an engineering firm under the responsibility of Freyssinet France.

The minimal spacing of the Fondapieu piles is as follows:

- 0.80 m between 2 FD 60s,

- 1.30 m between 2 FD 9s,

- 1 m between 1 FD 60 and 1 FD 90.

B. References The Fondapieu pile system has been used for seven years and

was covered by an ATEx**** in 2005 during the restoration of the Senlis-le-Sec church in the Somme.

Main Fondapieu jobsites:

Town RAMPARTS GERBEROY (60) 24 lm*

CHURCH GILOCOURT (60) 42 lm

Holy Family SCHOOL ALBERT (80) 49 lm

LENGLET ramparts PICQUIGNY (80) 21 lm

CHURCH FAYS LES ETANGS (60) 50 lm

Individual home, COLE SURESNES (92) 48 lm

Town RAMPARTS HAM (80) 70 lm

Individual home, GHEYSSENS

OUDEZELLE (59) 40 lm

Individual home, RIGAL ALBI (81) 36 lm

CHURCH SENLIS LE SEC (80) 604 lm

CHURCH ETELFAYE (80) 124 lm

HORSE RACETRACK ABBEVILLE (80) 167 lm

Individual home, RULENCE

AMIENS (80) 189 lm

SCI CUSTINE (property company)

PARIS. 18 (75) 30 lm

CHURCH LE SAULCHOY (80) 30 lm

Individual home, BORN SI ANDRE CORSY (01) 62 lm

Individual home, MONTREUIL

BILLY BERCLAU (62) 70 lm

Individual home, SLASKI BERCK SUR MER (62) 215 lm

Individual home, SANDRON

CESSIERES (02) 145 lm

Individual home, BARBIER BOUSSE (57) 126 lm

Individual home, LAHIR NOMENY (54) 195 lm

Individual home, BIANCALE

SOUCIEU EN JARREST (69) 42 lm

Individual home, LAGUENS

LE LUC (83) 64 lm

Individual home, PETIT PREZ

LESTREM (62) 76 lm

Individual home, WATTELLIER

HOUCHAIN (62) 63 lm

MAZARS Restaurant SAINT MARCEL (07) 104 lm

Individual home, JOUANNET

POITIERS (07) 140 lm

*lm = linear meters

****

ATEx – Appréciation Technique d’Expérimentation (Technical Experimentation Assessment) (Usually a basis for a future Technical Assessment)

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Technical file Tables and Figures

TABLE 1

Fondapieu Pile Product Line

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TABLE 1 BIS

Fondapieu pile Accessories

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FIGURE 1

Fondapieu pile product line

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FIGURE 2

Fondapieu pile element FD90

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FIGURE 3

Assembly studs

(a) (b) (c)

FIGURE 4

Buffer caps: (a) power hammer model, (b) Rhino model, (c) MAP model (independently operating pile inserter)

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FIGURE 5

Assembly stud, φφφφ 26 mm

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FIGURE 6

Manual assistance to the rotation with the ratchet spanner

FIGURE 7

Connecting bracing plate at the head of the Fondapieu pile

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FIGURE 8

Independently Operating Pile Inserter (IOPI )

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Reference

Designation

LENGTH

Mass (weight)

In kg

0.24m 0.50 m 1 m (for 1 m)

FD- 60 PILE Ø 60 solid (1 stud) * 4.60

FD-60P PILE Toe Ø 60 solid (1 stud) * 4.50

FD-60 length 500 PILE Ø 60 solid (1 stud) *

FD-60 length 240 PILE Ø 60 solid (1 stud) *

FDL-60 PILE Ø 60 smooth (1 stud) * 7.60

FDL-60 length 500 PILE Ø 60 smooth (1 stud) *

FDLi-60 PILE Ø 60 smooth, injectable, without branches (1 stud) * 7.50

FDLi-60 length 500 PILE Ø 60 smooth, injectable, without branches (1 stud *

FDi-60 PILE injectable Ø 60 (1 stud) * 4.40

FDi-60 P PILE toe injectable Ø 60 (1 stud) * 4.10

FDi-60 Top PILE Ø 60 top, injectable, without branches (1 stud) * 4.20

FDi-60 length 500 PILE Ø 60 injectable (1 stud) *

FDi-60 Top length 500 PILE Ø 60 top injectable, without branches (1 stud) *

FD-90 PILE Ø 90 solid (1 stud) * 10.20

FD-90P PILE Ø 90 toe solid monoblock (1 stud) * 10.00

FD-90 length 500 PILE Ø 90 solid (1 stud) *

FD-90 length 240 PILE Ø 90 solid (1 stud) *

FDL-80 PILE Ø 80 smooth (1 stud) * 13.50

FDL-80 length 500 PILE Ø 80 smooth (1 stud) *

FDLi-80 PILE Ø 80 smooth, injectable, without branches (1 stud) * 13.40

FDLi-80 length 500 PILE Ø 80 smooth, injectable, without branches (1 stud) *

FDi-90 PILE Ø 90 injectable(1 stud) * 10.10

FDi-90 P PILE injectable toe Ø 90 (1 stud) * 9.90

FDi-90 Top PILE Ø 90 top injectable, without branches (1 stud) * 10.00

FDi-90 length 500 PILE Ø 90 injectable(1 stud) *

FDi-90 Top length 500 PILE Ø 90 top injectable, without branches (1 stud) *

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Reference Designation

G 20 P Stud, aluminium, anodised Ø 20 Solid

G 20 C Stud, aluminium, anodised Ø 20 Hollow

G 26 P Stud, aluminium, anodised Ø 26 Solid

G 26 C Stud, aluminium, anodised Ø 26 Hollow

ECR D20 Nut, aluminium anodised Ø 20 Hexagonal 41 length 30

ECR D26 Nut, aluminium anodised Ø 26 Hexagonal 46 length 30

ECR D20 B Nut, aluminium as-cast Ø 20 Hexagonal 41 length 30

ECR D26 B Nut, aluminium as-cast Ø 26 Hexagonal 46 length 30

RON D20 Washer, aluminium anodised Ø 20.3 thickness 5

RON D26 Washer, aluminium anodised Ø 26.3 thickness 5

PLAT FD60 Bracing plate 100 x 100 x 10 / Bar tor Ø 10 length 250

PLAT FD90 Bracing plate 120 x 120 x 10 / Bar tor Ø 12 length 250

KIT FD60 1 FD-60 length 600 + FD-60 length 400 (2 studs)

KIT FD90 1 FD-90 length 600 + FD-90 length 400 (2 studs)

C.P. FD60 Complete support bracket for FD60

C.P. FD90 Complete support bracket for FD90

C.A. FD60 Complete bearing bracket for FD60

C.A. FD90 Complete bearing bracket for FD90

S.F.S. FD60 Complete dry foundation support for FD60

S.F.S. FD90 Complete dry foundation support for FD90

S.D.B. FD60 Complete concrete slab support for FD60

S.D.B. FD90 Complete concrete slab support for FD90

INJECT FD60 Disposable plastic injector for FD60

INJECT FD90 Disposable plastic injector for FD90

PINCE S Standard gripper, adaptable on valve ¾ and injectors FD 60/90

KIT DT Cutting-tapping kit FD60/FD90, complete kit

ROND 60/90 2 tapped aluminium round bars (1FD60 + 1FD90) Ø 107 stroke height

TIGE M20 Threaded rod, anodised aluminium M20 length 200 mm

TIGE M26 Threaded rod, anodised aluminium M26 length 250 mm

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The Fondapieu pile product line, diameter 60 mm or 90 mm

The conventional Fondapieu pile

The injectable Fondapieu pile

Haut = top

The smooth Fondapieu pile

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Figure 2

3 filets =Triple thread

Figure 5

3 filets =Triple thread

Brush the inlets and the outlets of the threads

Hard black anodising µ20