Girder element for concrete formwork comprising a structure for automatically compensating bending strains

Abstract

A girder element ( 1; 21; 31; 41; 53 - 57 ) for concrete formwork comprises a girder ( 4 ) for receiving external forces ( 10 ), a tension rod ( 5 ) extending behind the girder ( 4 ) and at least one lengthwise adjustable tensioning device that is interposed between the girder ( 4 ) and the tie rod ( 5 ), the local distance between the girder ( 4 ) and the tie rod ( 5 ) being adjustable by means of said tensioning device. The invention is characterized in that the lengthwise adjustable tensioning device is configured as a lengthwise adjustable compensation device ( 6; 6 a, 6 b ) which is motor driven to adjust the length of the compensation device ( 6; 6 a, 6 b ). A measuring device is used to determine the position (x) of the girder ( 4 ) in the area of the compensation device ( 6; 6 a, 6 b ) relative to a desired position (xs). A control device ( 12 ) is used to adjust the length (L) of the compensation device ( 6; 6 a, 6 b ) depending on the position (x) of the girder ( 4 ). The girder element permits precise and cost-effective manufacture of any concrete structures.

1 - 15 . (canceled) 
   
   
       16 . A girder structure of a ceiling formwork for producing a concrete floor level, the structure comprising:
 first girder elements for absorbing external forces;   second girder elements for absorbing the external forces, said second girder elements disposed on and attached to said first girder elements;   a traction band, which runs behind a second girder of said second girder elements;   at least one length-adjustable tensioning device disposed between said second girder and said traction band to set a local spacing between said second girder and said traction band, said length-adjustable tensioning device implemented as a length-adjustable compensation device having a motorized drive for setting a compensation device length thereof;   a measuring unit for determining, at an area of said compensation device, a position of said second girder relative to a target position thereof;   a control unit for regulating said compensation device length as a function of said position of said second girder; and   formwork girders disposed on said first girder elements, said formwork girders having a structural height which slightly exceeds that of said second girder elements.   
   
   
       17 . The girder structure of  claim 16 , further comprising an additional girder on which said formwork girders also seat, wherein, said traction band, said second girder, a connection element and said additional girder are attached to each other in cooperation with said compensation device. 
   
   
       18 . The girder structure of  claim 17 , wherein said additional girder extends parallel to said first girder elements. 
   
   
       19 . The girder structure of  claim 16 , wherein said first girder elements comprise two first girders and said second girder elements comprise three second girders. 
   
   
       20 . The girder structure of  claim 16 , wherein said first girder elements and said second girder elements cross at right angles. 
   
   
       21 . The girder structure of  claim 16 , wherein said motorized drive comprises an electrical drive. 
   
   
       22 . The girder structure of  claim 21 , wherein said electrical drive comprises a linear motor. 
   
   
       23 . The girder structure of  claim 16 , wherein said motorized drive comprises a hydraulic drive or a pneumatic drive. 
   
   
       24 . The girder structure of  claim 16 , wherein said measuring unit comprises a spacer rod or a cable having deflection roller and ballast or a laser distance meter. 
   
   
       25 . The girder structure of  claim 16 , wherein said compensation device is length-adjustable in a direction which extends essentially perpendicular to said second girder. 
   
   
       26 . The girder structure of  claim 16 , wherein a first girder of said first girder elements has fasteners disposed on two opposite ends thereof. 
   
   
       27 . The girder structure of  claim 26 , wherein said fasteners are disposed, structured and dimensioned for fastening to story columns. 
   
   
       28 . The girder structure of  claim 16 , wherein at least one of said first and said second girder elements is telescoping. 
   
   
       29 . The girder structure of  claim 16 , wherein said first girder elements have fasteners for fastening a plurality of said formwork girders to said first girder elements. 
   
   
       30 . The girder structure of  claim 16 , wherein multiple length-adjustable compensation devices are distributed over a length of said second girder. 
   
   
       31 . The girder structure of  claim 16 , further comprising a signal device for output of a warning signal or of an acoustic, optical, or electronic warning signal, when a limiting value for said position of said second girder is exceeded. 
   
   
       32 . Use of the girder structure of  claim 16 , for continuous compensation of bending deformations of a girder of girder elements, wherein a changeable external force acts on the girder. 
   
   
       33 . The use of  claim 32 , wherein the external force on the girder is caused by a weight of concrete.