Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B1/00—Producing shaped prefabricated articles from the material
  • B28B1/08—Producing shaped prefabricated articles from the material by vibrating or jolting
  • B28B1/093—Producing shaped prefabricated articles from the material by vibrating or jolting by means directly acting on the material, e.g. by cores wholly or partly immersed in the material or elements acting on the upper surface of the material
  • B28B1/0935—Producing shaped prefabricated articles from the material by vibrating or jolting by means directly acting on the material, e.g. by cores wholly or partly immersed in the material or elements acting on the upper surface of the material using only elements wholly or partly immersed in the material, e.g. cores
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B17/00—Details of, or accessories for, apparatus for shaping the material; Auxiliary measures taken in connection with such shaping
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
  • E04G17/00—Connecting or other auxiliary members for forms, falsework structures, or shutterings
  • E04G17/002—Workplatforms, railings; Arrangements for pouring concrete, attached to the form
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
  • E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
  • E04G21/02—Conveying or working-up concrete or similar masses able to be heaped or cast
  • E04G21/06—Solidifying concrete, e.g. by application of vacuum before hardening
  • E04G21/08—Internal vibrators, e.g. needle vibrators

Definitions

• An internal vibrator consists of a vibrating tube, the high frequency vibrations of which are often achieved by means of an internal rotating eccentric within the tube.
• the vibrating tube is lowered into concrete, the concrete is subjected to very rapid vibration.
• the internal friction of the concrete is to all intents and purposes eliminated, which implies that the concrete becomes less viscous, settles and compacts.
• the majority of the air which is trapped within the concrete and which for normal concrete consistencies can make up some 5-20 % of the total volume, is forced out of the concrete and thus a non- porous and homogeneous concrete is obtain.
• the low viscosity consistency of the concrete which is imparted by the vibrations further implies that the concrete will flow into any parts of the mould which are relatively inaccessible and surround any reinforcement which may be present.
• vibration work is carried out using an internal vibrator which is manually inserted into the concrete in the mould to a certain depth following a predetermined pattern. Thereafter, the internal vibrator is very slowly pulled out of the concrete so that air-pockets will not be formed during the removal.
• Such work is clearly very time consuming and places high demands on accuracy and precision during its performance. In addition, the work is very heavy. Furthermore, once the work has been carried out, it is virtually impossible to check, and the consequences of insufficient vibration will not be apparent until the casting mould is removed or perhaps not before the cast concrete construction is loaded.
• the invention also relates to a method for vibrating concrete in a casting mould using an internal vibrator, characterized in that the displacement sequence of the internal vibrator is automatically controlled by means of a control unit which operates means to displace the internal vibrator horizontally and vertically according to a predetermined pattern.
• Fig. 1 shows a schematic perspective view of an arrangement according to an embodiment of the invention connected to a casting mould
• Fig. 2 shows the arrangement and the casting mould of Fig. 1 in a partially sectioned side view.
• a casting mould 6 for a wall element is schematically illustrated in which two casting layers Cl and C2 have been introduced.
• the arrows P1-P6 symbolize the various phases in a vibration cycle for the casting layer C2
• reference numerals 4 l r 4 2 and lj, 1 2 denotes two different positions of the trolley 4 and the internal vibrator 1 respectively.
• Reference numerals 101,, 102 2 denote the lowest positions of the internal vibrator 1 in two successive vibration cycles in the casting layer Cl.
• a switched-on internal vibrator is lowered through the casting layer C2 with a speed of approximately 0.1 m/s until the upper end of the internal vibrator reaches the bottom of the casting layer C2.
• phase P3 vibration takes place with a stationary internal vibrator 1, for a time interval which is typically 5-15 seconds.
• the position of the internal vibrator 1, is chosen so that good shaking down of the casting layers Cl, C2 is achieved.
• the internal vibrator is raised in a switched-off condition through the air and thereafter the trolley 4 is moved, and therewith it the internal vibrator, during phase P6 from the position 4, to the position 4 2 .
• the vibration cycle is thereby terminated and a new vibration cycle begins.
• the distance L by which the trolley 4 is displaced is dependent on the effective radius of the internal vibrator (typically 40 cm) , the reinforcement density and the demands on non- porosity of the completed wall element. Normally, the distance L is between 0.3-0.5 m.
• the length of the wall element in the X-direction is often a multiple of 2.4 m, thereby implying that a plurality of vibration cycles must be effected in each casting layer.
• the height in the Z-direction is typically 2.5 m, which normally requires three casting layers.
• the width of the wall element is normally 16-18 cm, maximum 30 cm. With the widest walls, a double submersion of the internal vibrator is required.
• the connection between the guide tube 11 and the rest of the trolley 4 is advantageously flexible so that the vertical extension of the guide tube can be placed at any location across the width of the mould 6.
• the displacement path for the internal vibrator which is theoretically calculated by the computer is suitably tested in an empty casting mould in order to establish that the internal vibrator during actual casting will not contact the mould or any obstructions therein.
• the test is performed with a switched-off internal vibrator and with higher lowering and lifting speeds than with the casting.
• the internal vibrator is placed at a height above the already-vibrated casting layer which corresponds to the height of the subsequent casting layer in order to provide an indication as to when the pouring of the subsequent layer shall cease.
• the carrier trolley for the internal vibrator can have a different shape, for example it can be supported on the top surface of the casting mould and can run in tracks formed on the upper surfaces of the corresponding mould halves.
• the control unit control several trolleys provided with internal vibrators so as to accelerate the vibration of each casting layer.
• the arrangement according to the invention can also be adapted to casting of objects other than wall elements.

Landscapes

• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Structural Engineering (AREA)
• Civil Engineering (AREA)
• Ceramic Engineering (AREA)
• Manufacturing & Machinery (AREA)
• On-Site Construction Work That Accompanies The Preparation And Application Of Concrete (AREA)
• Road Paving Machines (AREA)
• Sampling And Sample Adjustment (AREA)
• Mixers With Rotating Receptacles And Mixers With Vibration Mechanisms (AREA)
• Vibration Prevention Devices (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=20386610

Family Applications (1)

Country Status (8)

Families Citing this family (11)

Family Cites Families (3)

• 1992
  • 1992-06-25 SE SE9201965A patent/SE500828C2/sv unknown
• 1993
  • 1993-06-23 DE DE69314036T patent/DE69314036T2/de not_active Expired - Fee Related
  • 1993-06-23 WO PCT/SE1993/000560 patent/WO1994000281A1/en active IP Right Grant
  • 1993-06-23 DK DK93915070.2T patent/DK0651691T3/da active
  • 1993-06-23 CA CA002138545A patent/CA2138545A1/en not_active Abandoned
  • 1993-06-23 JP JP6502264A patent/JPH07508231A/ja not_active Ceased
  • 1993-06-23 EP EP93915070A patent/EP0651691B1/de not_active Expired - Lifetime
  • 1993-06-23 AT AT93915070T patent/ATE158221T1/de not_active IP Right Cessation

Non-Patent Citations (1)

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