WO1994017252A1 - Ameliorations relatives a des fondations - Google Patents

Ameliorations relatives a des fondations Download PDF

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Publication number
WO1994017252A1
WO1994017252A1 PCT/GB1994/000116 GB9400116W WO9417252A1 WO 1994017252 A1 WO1994017252 A1 WO 1994017252A1 GB 9400116 W GB9400116 W GB 9400116W WO 9417252 A1 WO9417252 A1 WO 9417252A1
Authority
WO
WIPO (PCT)
Prior art keywords
mandrel
pier
building structure
floor slab
foundation
Prior art date
Application number
PCT/GB1994/000116
Other languages
English (en)
Inventor
Roger Alfred Bullivant
Original Assignee
Roxbury Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Roxbury Limited filed Critical Roxbury Limited
Priority to GB9514216A priority Critical patent/GB2289494B/en
Priority to AU58635/94A priority patent/AU5863594A/en
Publication of WO1994017252A1 publication Critical patent/WO1994017252A1/fr

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D27/00—Foundations as substructures
    • E02D27/10—Deep foundations
    • E02D27/12—Pile foundations
    • E02D27/14—Pile framings, i.e. piles assembled to form the substructure
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
    • E02D5/38—Concrete or concrete-like piles cast in position ; Apparatus for making same making by use of mould-pipes or other moulds
    • E02D5/385—Concrete or concrete-like piles cast in position ; Apparatus for making same making by use of mould-pipes or other moulds with removal of the outer mould-pipes

Definitions

  • the present invention concerns improvements in or relating to foundations, especially but not exclusively vertical foundations in ground, the condition of which can be termed good to marginal.
  • piles are employed, being driven into the ground to reach down to lower firmer strata and/or providing f ⁇ ctional support thus increasing load bearing capacity, not only as a result of the firmer strata acting indirectly as a foundation pad but also as a result of the f ⁇ ctional effects of the ground on the shaft of the pile, these effects increasing the load bearing characteristics of the pile.
  • Current piles generally have a length which is much in excess of their diameter or thickness. For example, a square cross-section pile having a thickness of 250 mm often has a length of 10 metres. The ratio of length to thickness is expressed as the slenderness aspect ratio, the example quoted above giving an aspect ratio of 40.
  • the provision of foundation pads, strip foundations and piles can all be relatively expensive and are often dependent upon the conditions of
  • a foundation pier comprising a member with a vertical or generally vertical axis and an aspect ratio of no greater than 10, having downwardly converging sides formed from a cementitious material cast in situ in a preformed hole in the ground.
  • the member is an inverted conical f r u s t um .
  • the sides of the cone are inclined at 2.5° to the vertical.
  • the member may be triangular, rectangular, pol y gona l or elliptical in cross-section.
  • the member incorporates reinforcement.
  • the member has an upper diameter of 0.2 to 1 metres and a length between 2 and 10 metres.
  • the member incorporates holding down means for a building structure to be supported on the pier.
  • the holding down means may be fixing bolts.
  • the fixing bolts are attached to the reinforcement within the member.
  • a method of forming a foundation pier comprising forcing a downwardly converging mandrel into the ground to a predetermined depth to form a hole of corresponding shape having an aspect ratio of no greater than 10, removing the mandrel and filling the hole with a settable material.
  • the hole may be filled simultaneously with or after removal of the mandrel.
  • reinforcement means are fitted in the hole.
  • the reinforcement means may incorporate holding down means for a building structure to be supported on the pier.
  • the mandrel is forced into the ground by hammering. Alternatively it may be vibrated into the ground.
  • the mandrel is guided such that its longitudinal axis remains substantially vertical as it is driven.
  • the mandrel is extended in length by fitting a hollow extension of external dimensions smaller than the upper end of the mandrel to its upper end.
  • Another aspect of the present invention provides a building structure supported on a plurality of primary foundation piers of the type described in any of the preceding ten paragraphs, the building structure
  • additional piers may be provided below the floor slab.
  • the floor slab and primary piers are capable of mutual vertical displacement.
  • the floor slab is tied against
  • connection for the floor slab to each pier comprises one or more vertical tubes attached to the pier and mounting, for sliding movement along the axis of the tube, a bar connected to reinforcement of the floor slab.
  • the floor slab is a dual spanning floor slab.
  • the floor slab is supported during its formation on a layer of insulating material, for example by the said beams, which ground is made up to the required level prior to laying the layer.
  • holding down means for the building structure are formed in the primary foundation piers and are capable of resisting horizontal and turning moment loading. They may comprise mutually spaced holding down assemblies, each of which is mounted in a single pier.
  • the longer transverse axis is arranged generally at right angles to the horizontal load or tilting moment to be resisted.
  • Fig. 1 shows a mandrel for forming a pier
  • Fig. 2 shows a pier formed in situ
  • Fig. 3 shows a plan view of a section of the perimeter of a building supported on a pier
  • Fig. 4 shows a diagrammatic view of means for connecting a floor slab to a pier
  • Fig. 5 shows a plan view of an alternative pier
  • Fig. 6 shows an alternative mandrel assembly
  • Figs. 7 and 8 show alternative assemblies for guiding the mandrel.
  • the mandrel shown in Fig. 1 is intended to be hammered into good to reasonable ground by a pile driving hammer impacting upon the upper impact member 10 of the mandrel.
  • the mandrel comprises a- mild steel conical sleeve 12 mounted to a steel driving tube 14 connected to the pad 10 and to the sleeve 12 by a plurality of ribs 16 which, at their upper ends, may include apertures 18 for mounting handling shackles (not shown).
  • the mandrel is between 2 and 6 metres long and it has a slenderness or aspect ratio which is not greater than 10. The aspect ratio is obtained by dividing the length of the mandrel by its diameter.
  • the angle of inclination of the walls forming the sleeve 12 to the vertical is between 1° and 3° and preferably around 2 1 ⁇ 2 °.
  • the sleeve is provided with a conical tip 20 which, in certain instances, may be sacrificial, that is, it may be left down the hole formed by the mandrel. Normally it is fixed to the end of the mandrel and removed from the hole on removal of the mandrel.
  • Figs. 7 and 8 illustrate two guide assemblies for achieving this, especially during the initial driving steps.
  • the guide assembly shown in Fig. 7 comprises a removable clamp 70 temporarily attached to the mandrel approximately midway along the pile driver mast 72 by a slider assembly 74 and moves vertically down the mast during the initial driving of the mandrel.
  • the clamp is released when the mandrel is embedded sufficiently in the ground to ensure that further driving will be generally vertical.
  • the mandrel is provided with two diametrically opposed guide fins 76 which on driving slide through a slot 78
  • a reinforcing cage 22 which has been designed in accordance with the loading conditions to be supported, is then placed in the hole which is immediately filled with concrete 24 which can be prepared on site.
  • the concrete can be poured as the mandrel is removed. It is supplied to the interior of the ascending mandrel and enters the hole through the hole in the base left by the sacrificial tip. The reinforcement is placed into the poured concrete before it sets.
  • the mandrel can be vibrated into the ground but this is in some instances undesirable because the vibration tends to liquify certain soils as opposed to the compaction of the soil achieved by the downwardly converging mandrel when it is hammered into the ground.
  • the hole may collapse after vibratory driving. Additionally the reactive force on the mandrel cannot readily be perceived in a vibratory insertion method. It will be realised therefore that the
  • consolidating force of the downwardly converging mandrel can enhance the load bearing capacity of the ground to make it sufficiently good to support the foundation pier.
  • the foundation pier thus relies on an operating concept which is revolutionary different from existing concepts. With the pier the load is supported
  • Fig. 9 illustrates a situation where the
  • foundation pier is utilised in ground where the top layer T does not provide good load bearing
  • the modified mandrel shown in Fig. 9 obviates this problem.
  • the mandrel shown is similar to that
  • Fig. 1 has a tubular extension 90 at its upper end, the length of the extension being greater than the depth of the layer T and the diameter less than the diameter of the mandrel at its top.
  • a bond breaking band 92 is provided at the top of the mandrel and has a diameter slightly greater than the diameter of the top of the mandrel.
  • extension 90 could converge upwardly.
  • bond breaker 92 and/or the tapering extension means that there is relatively little contact between the ground and the extension 90 over the layer T and the loading on the pier is picked up over the layer L.
  • the poor ground conditions over the layer T often results in soil falling into the hole formed by the mandrel on its removal from the ground. This can be avoided by filling the hole with concrete through the tip of the mandrel as it is removed. Alternatively, and bearing in mind the ground over the length L is unlikely to collapse, means can be provided at the top of the mandrel to collect soil falling into the hole from the layer T and to collect it for removal on the top of the mandrel.
  • foundation piers are arranged generally around the periphery of the building at predetermined spaced intervals.
  • the foundation piers 28 (only one of which is shown in Fig. 3) have been formed subsequent construction of the building to be supported thereon commences with the laying prefabricated beams 30, between each pier.
  • each pier normally supports a stanchion 32 or portal frame of the building, the stanchion or frame being held down by the fixing bolts 26.
  • Peripheral walls can be built on the beams 30 and roofs, etc. supported on the portal frames.
  • the floor of the building is cast in situ and it is desirable that after casting mutual vertical movement between the floor and the pier can be allowed.
  • floor is a cast in situ, dual-spanning concrete floor which is formed within shuttering
  • polystyrene slab laid in the ground to isolate the floor from the ground.
  • Clearly appropriate reinforcement 34 (Fig. 4) will be placed on the polystyrene slab prior to the pouring of the floor concrete.
  • the slab is laid directly on the ground and if the level thereof is not as desired then it is made up by earth excavated from the site or imported material.
  • transversley extending reinforcing members 36 are cast into the top of the pier 28 and are connected to a pair of vertically extending metal sleeves 38.
  • the reinforcement 34 of the floor slab is bent such that it has a vertically extending section 40 passing through the tube 38, obviously, this being placed before the floor slab is poured.
  • a metal isolation sheet 42 covers that surface o f the pier 28 against which the floor is cast. It will be realised therefore that when the floor is cast it is isolated from the pier 28 by the sheet 42 and consequently movement in a vertical direction between the two can take place while the connection of the reinforcement 34 with the tubes 30 prevents relative horizontal movement.
  • Fig. 3 shows a modified pier which has a
  • a pier of this shape is designed to resist horizontal or tilting loads on the pier acting in a direction generally perpendicular to the axis of the beams 30.
  • the pier may have a triangular, rectangular, elliptical or any other suitable cross-section.
  • Fig. 5 shows a plan view of a modified pier arranged to support a stanchion 32 at an intermediate location within the building structure.
  • the pier is of the conical configuration shown in Fig. 2 and has a substantially square surrounding steel sleeve 42' to isolate it from the floor slab, each corner of the sheet including tubes 38 through which the floor slab reinforcing bars 34 can slide.
  • a conical cross-section pier is generally the preferred form but eliptical, rectangular, square polygonal and other piers may be employed, provided that the aspect ratio is less than 10 and that the pier converges in the downward direction.
  • the mandrel is hammered into the ground but vibratory driving techniques may be employed.
  • To remove a mandrel when it has been driven to the desired depth may be achieved by ensuring that the impact force of the hammer is converted to an upward direction to relieve the stiction between the mandrel sleeve and the surrounding ground.
  • Fig. 6 shows an alternative mandrel assembly which has been designed with a view to ensuring that when the mandrel is driven into the ground its axis remains substantially vertical.
  • the assembly comprises a guide tube 50 having lugs 52 for mounting it to a vehicle.
  • a mandrel 54 which is similar to the mandrel described with reference to Fig. 1 has a cylindrical portion 56 at its upper end which is slidably mounted and thereby guided within the tube 50.
  • the assembly is designed so that the centre of gravity of the driving mass 58, conveniently of lead or any other dense material, is located at a considerable distance below the upper end of the mandrel.
  • the mass 58 is located in the mandrel and has an external profile, in the case shown in the drawing, a step profile, which is complimentary to the internal profile of the mandrel.
  • the mandrel is provided with a striking surface 60 and a hammering mass 58 is connected to an hydraulic piston and cylinder device 62 which allows it to be raised and then dropped against the striking surface 60 at an impact rate of, for example, 60 blows per minute.
  • a hammering mass 58 is connected to an hydraulic piston and cylinder device 62 which allows it to be raised and then dropped against the striking surface 60 at an impact rate of, for example, 60 blows per minute.
  • the piston and cylinder device 62 is
  • Latch means (not shown) are provided to connect the mandrel 54 to the sleeve 50 when the mandrel has been driven to a predetermined depth.
  • the rams 66 located at the base of the sleeve the mandrel assembly can be lifted thereby extracting the mandrel from the hole that it has formed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Paleontology (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Bridges Or Land Bridges (AREA)

Abstract

On réalise un pilier (28) de fondation destiné à une structure de construction en formant dans le sol un trou convergent vers le bas par exemple en martelant ou en faisant vibrer un mandrin conique (10, 12, 14) dans le sol, puis en remplissant le trou de béton (24) pour former un pilier dont le coefficient d'élancement ou le rapport d'élancement longueur/épaisseur est inférieur ou égal à 10. Des poutrelles (30) préfabriquées sont placées entre des piliers (28) adjacents sur lesquelles la structure est construite et un tablier est coulé in situ en utilisant les poutrelles (30) comme coffrage latéral.
PCT/GB1994/000116 1993-01-30 1994-01-21 Ameliorations relatives a des fondations WO1994017252A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB9514216A GB2289494B (en) 1993-01-30 1994-01-21 Improvements in or relating to foundations
AU58635/94A AU5863594A (en) 1993-01-30 1994-01-21 Improvements in or relating to foundations

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9301891.9 1993-01-30
GB939301891A GB9301891D0 (en) 1993-01-30 1993-01-30 Improvements in or relating to foundations

Publications (1)

Publication Number Publication Date
WO1994017252A1 true WO1994017252A1 (fr) 1994-08-04

Family

ID=10729610

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1994/000116 WO1994017252A1 (fr) 1993-01-30 1994-01-21 Ameliorations relatives a des fondations

Country Status (3)

Country Link
AU (1) AU5863594A (fr)
GB (2) GB9301891D0 (fr)
WO (1) WO1994017252A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0758699A1 (fr) * 1995-07-31 1997-02-19 Dipl.Ing. Helmut Hemmerlein GmbH & CO. Bau KG. Procédé d'installation de pieux cÔniques, pieux correspondants, et fondation à pieux ainsi obtenue
WO1999009261A1 (fr) * 1997-08-20 1999-02-25 Roxbury Limited Traitement des terrains
FR2777310A1 (fr) * 1998-04-09 1999-10-15 Bernad Dispositif de foncage de trous dans le sol pour massifs de scellement de poteaux de cloture
CN101812843A (zh) * 2010-04-20 2010-08-25 黑龙江省东煤建筑基础工程有限公司 中心灌注后压浆桩施工方法及其使用的灌注器和注浆器
RU168119U1 (ru) * 2016-08-01 2017-01-18 федеральное государственное бюджетное образовательное учреждение высшего образования "Пермский национальный исследовательский политехнический университет" Буронабивная свая

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE498717A (fr) *
US4023325A (en) * 1975-11-11 1977-05-17 Paverman Grisha H Load bearing reinforced ground slab
EP0073859A1 (fr) * 1981-12-22 1983-03-16 Ballast-Nedam Groep N.V. Méthode de construction d'une structure de bâtiment et ossature de pieux pour cette structure
GB2216153A (en) * 1988-03-25 1989-10-04 Roydon John Chute Thompson Permanent shuttered in situ beam foundation system

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1887604A (en) * 1930-02-24 1932-11-15 Toyo Kompuresoru Kabushiki Kai Apparatus for forming concrete piles
GB9107672D0 (en) * 1991-04-11 1991-05-29 Roxbury Ltd Improvements in or relating to piles

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE498717A (fr) *
US4023325A (en) * 1975-11-11 1977-05-17 Paverman Grisha H Load bearing reinforced ground slab
EP0073859A1 (fr) * 1981-12-22 1983-03-16 Ballast-Nedam Groep N.V. Méthode de construction d'une structure de bâtiment et ossature de pieux pour cette structure
GB2216153A (en) * 1988-03-25 1989-10-04 Roydon John Chute Thompson Permanent shuttered in situ beam foundation system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0758699A1 (fr) * 1995-07-31 1997-02-19 Dipl.Ing. Helmut Hemmerlein GmbH & CO. Bau KG. Procédé d'installation de pieux cÔniques, pieux correspondants, et fondation à pieux ainsi obtenue
WO1999009261A1 (fr) * 1997-08-20 1999-02-25 Roxbury Limited Traitement des terrains
GB2345509A (en) * 1997-08-20 2000-07-12 Roxbury Ltd Ground treatment
GB2345509B (en) * 1997-08-20 2002-05-08 Roxbury Ltd Ground treatment
US6505998B1 (en) 1997-08-20 2003-01-14 Global Innovations, Inc. Ground treatment
FR2777310A1 (fr) * 1998-04-09 1999-10-15 Bernad Dispositif de foncage de trous dans le sol pour massifs de scellement de poteaux de cloture
CN101812843A (zh) * 2010-04-20 2010-08-25 黑龙江省东煤建筑基础工程有限公司 中心灌注后压浆桩施工方法及其使用的灌注器和注浆器
RU168119U1 (ru) * 2016-08-01 2017-01-18 федеральное государственное бюджетное образовательное учреждение высшего образования "Пермский национальный исследовательский политехнический университет" Буронабивная свая

Also Published As

Publication number Publication date
GB9514216D0 (en) 1995-09-27
GB9301891D0 (en) 1993-03-17
GB2289494A (en) 1995-11-22
AU5863594A (en) 1994-08-15
GB2289494B (en) 1997-01-08

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