Grip reinforcing bar and method of producing same

Abstract

A reinforcing bar with improved adherence for reinforced concrete component, consists of a metal profile section ( 1 ) in the form of a flattened strip of rectangular cross section with two opposite wide faces ( 10, 10 ′) on which longitudinally separated projecting anchoring portions are formed.

1 . A reinforcing bar with improved adherence for a reinforced concrete component, consisting in of a metal section ( 1 ) extending in a longitudinal direction, having the form of a flattened strip of substantially rectangular cross-section, with two opposite wide faces ( 10 ,  10 ′) extending between two lateral sides ( 11 ,  11 ′) and including a plurality of projecting anchoring portions which are longitudinally separated from each other and bearing on the concrete in a direction opposite to a tensile force applied to the bar ( 1 ),
 characterized in that each of the two wide faces ( 10 ,  10 ′) of the strip is provided with a series of anchoring portions in the form of elongated locks ( 2 ,  24 ) separated from each other by hollow portions ( 3 ,  3 ′) in the form of grooves and extending transversally over the whole width of the strip ( 1 ), substantially up to the lateral sides ( 11 ,  11 ′) thereof, and each of said elongated locks ( 2 ) extends in projection over a small height, not exceeding a quarter of the thickness of the strip ( 1 ), and has, in cross-section, a substantially trapezoidal profile, with an embossed face ( 21 ) of small width with respect to its length and two inclined flanks ( 22 ,  23 ) for connection with the elongated bottom ( 31 ,  31 ′) of the adjacent grooves ( 3 ,  3 ′) that constitute, for each lock ( 2 ), two inclined faces ( 22 ,  23 ) that bear, each in one direction, on the coating concrete, said inclined faces ( 22 ,  23 ) each having an elongated shape extending between the two sides of the strip ( 1 ), so as to distribute the bearing forces over all the width thereof. 
 
     
     
         2 . The reinforcing bar according to  claim 1 , characterized in that, on each face ( 10 ,  10 ′) of the strip ( 1 ), the elongated locks ( 2 ,  2 ′) are spaced apart from each other by a constant pitch (c) that do not exceed half the width ( 1 ) of the strip ( 1 ). 
     
     
         3 . The reinforcing bar according to  claim 1 , characterized in that, on each face ( 10 ,  10 ′) of the strip ( 1 ), the embossed faces ( 21 ,  21 ′) of the elongated locks ( 2 ,  2 ′) have a width lower than half the width ( 1 ) of the strip ( 1 ). 
     
     
         4 . The reinforcing bar according to  claim 1 , characterized in that the elongated locks ( 2 ,  2 ′) extend transversally in directions inclined by a non-zero angle with respect to a longitudinal axis of each face ( 10 ,  10 ′) of the strip ( 1 ). 
     
     
         5 . The reinforcing bar according to  claim 4 , characterized in that the elongated locks ( 2 ,  2 ′) formed on the two faces ( 10 ,  10 ′), respectively, of the strip ( 1 ) are symmetrically inclined, in opposite directions, with respect to the longitudinal axis X′, X of the strip ( 1 ). 
     
     
         6 . The reinforcing bar according to  claim 4 , characterized in that, on each face ( 10 ,  10 ′) of the strip ( 1 ), the elongated locks ( 2 ,  2 ′) are parallel and inclined by an angle β comprised between 35° and 75°. 
     
     
         7 . The reinforcing bar according to  claim 3 , characterized in that the anchoring locks ( 2 ,  2 ′) formed on each wide face ( 10 ,  10 ′) of the strip ( 1 ) have the shape of imbricated V-shaped chevrons, with two rectilinear portions symmetrically inclined on either side of a longitudinal axis (X′, X) of the strip ( 1 ). 
     
     
         8 . The reinforcing bar according to  claim 4 , characterized in that the anchoring locks ( 2 ,  2 ′) formed on each wide face ( 10 ,  10 ′) of the strip ( 1 ) have a corrugated shape, symmetrical with respect to the longitudinal axis (X′, X) of the strip ( 1 ). 
     
     
         9 . The reinforcing bar according to  claim 1 , characterized in that, on each wide face ( 10 ,  10 ′) of the strip ( 1 ), the elongated anchoring locks ( 2 ,  2 ′) extend up to a small distance from each of the lateral edges ( 11   a ,  11   b ) of the strip ( 1 ), so as to leave a smooth flat ( 12 ) of small width along each of said edges ( 11 ,  11 ′). 
     
     
         10 . The reinforcing bar according to  claim 9 , characterized in that the flats ( 12 ) formed along the two lateral edges ( 11 ,  11 ′), respectively, of the strip ( 1 ), on each of wide faces ( 10 ,  10 ′) thereof, have a width of the order of 0.2 e, e being the average thickness of the strip. 
     
     
         11 . The reinforcing bar according to  claim 9 , characterized in that, on each wide face ( 10 ,  10 ′) of the strip ( 1 ), the embossed faces ( 21 ) of the locks ( 2 ) and the bottoms ( 31 ) of the grooves ( 3 ) are located in the two parallel planes, respectively, extending on either side of a mean plane Q of the wide face ( 10 ), in which are placed the two flats ( 12   a ,  12   b ) extending along the two lateral edges ( 11   a ,  11   b ), respectively, of the strip ( 1 ). 
     
     
         12 . The reinforcing bar according to  claim 11 , characterized in that the two planes in which are located the embossed faces ( 21 ) of the locks ( 2 ) and the bottoms ( 31 ) of the grooves ( 3 ), respectively, are spaced apart by a height h that can be from 0.08 e to 0.24 e, e being the average thickness of the strip ( 1 ). 
     
     
         13 . The reinforcing bar according to  claim 1 , characterized in that the connection flanks ( 22 ,  23 ) between the embossed faces ( 21 ) of the locks and the bottom ( 31 ) of the corresponding grooves ( 3 ) are inclined by an angle α of at least 45°, with respect to a plane in which said embossed faces ( 21 ) are placed. 
     
     
         14 . The reinforcing bar according to  claim 1 , characterized in that the anchoring locks ( 2 ) are longitudinally spaced by a pitch (c) comprised between one and three times the average thickness e of the strip ( 1 ). 
     
     
         15 . A reinforcing cage ( 7 ) for a reinforced concrete component ( 6 ) including two webs of reinforcing bars connected by stirrups and extending at a small distance of coating from two spaced-apart facings ( 61 ,  62 ), respectively, of the component ( 6 ), characterized in that at least one of the two webs of the cage consist in bars ( 71 ) with improved adherence according to  claim 1 , and in that the stirrups are formed of flat metal strips ( 73 ), alternately welded on the embossed faces ( 21 ) of the anchoring locks ( 2 ) of said improved-bond bars ( 71 ). 
     
     
         16 . A method of producing a reinforcing bar according to  claim 1 , characterized in that it is firstly made a metal bar ( 1 ) in the form of a flattened strip with two opposite wide faces ( 10 ,  10 ′) and centred on a longitudinal axis (x′ x), and in that said strip ( 1 ) is subjected to a rolling pass between two cylinders ( 5 ,  5 ′) rotating about axes ( 50 ,  50 ′) parallel to each other and orthogonal to the longitudinal axis (x′ x) of the strip ( 1 ), said cylinders ( 5 ,  5 ′) being provided, over their periphery, with spaced-apart recesses ( 51 ), for the formation, by rolling, of elongated locks ( 2 ) separated by parallel grooves ( 3 ), on each of the two wide faces ( 10 ,  10 ′) of the strip ( 1 ). 
     
     
         17 . The method according to  claim 16 , characterized in that the two rolling cylinders ( 5 ,  5 ′) are each provided, over their periphery, with an alternation of recesses ( 51 ) and teeth ( 52 ) intended to form the locks ( 2 ) and the grooves ( 3 ), respectively, on each of the wide faces ( 10 ,  10 ′) of the strip ( 1 ) and extending between two smooth portions ( 53 ) for the formation of two flats ( 12 ) along the two lateral sides ( 11   a ,  11   b ) of the strip ( 1 ). 
     
     
         18 . The method according to  claim 16 , characterized in that the recesses ( 51 ) for the formation of the locks ( 2 ) are regularly spaced apart along the periphery of each of the rolling cylinders ( 5 ,  5 ′). 
     
     
         19 . The method according to  claim 16 , characterized in that the recesses ( 51 ) are distributed along the periphery of each of the rolling cylinders ( 5 ,  5 ′) so as to periodically vary the spacing of the locks ( 2 ) obtained on each wide face ( 10 ,  10 ′) of the strip ( 1 ). 
     
     
         20 . The reinforcing bar according to  claim 2 , characterized in that, on each face ( 10 ,  10 ′) of the strip ( 1 ), the embossed faces ( 21 ,  21 ′) of the elongated locks ( 2 ,  2 ′) have a width lower than half the width ( 1 ) of the strip ( 1 ).