EP0785317A1

EP0785317A1 - Method for dimensioning reinforcement elements for reinforced concrete beams

Info

Publication number: EP0785317A1
Application number: EP96904103A
Authority: EP
Inventors: Isabel Merino Garay Olatz
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-03-02
Filing date: 1996-03-01
Publication date: 1997-07-23
Also published as: CN1150462A; BR9606236A; MX9605275A; WO1996027062A1; AU4832396A; JPH09512602A; CN1121540C; PL317066A1

Abstract

Method for dimensioning and constructing reinforcement elements for beams and pillars of reinforced concrete, consisting in dimensioning independently the horizontal and vertical branches of the transverse reinforcement element, in replacement of the adapters used heretofore, and making possible the prefabricated construction of any reinforcement element for reinforced concrete, with an important saving in materials and in space necessary for storing the constituents of the reinforcements for reinforced concrete.

Description

Until now, the reinforcement for reinforced concrete beams has been calculated in terms of width, height, length and the number and diameter of upper bars, which are generally the same length as the beam, and by the number and diameter of the bottom lengthwise bars, some of which may be the same length as the beam, and others, the so-called strengthening bars, which may be shorter. A beam also has stirrups, defined by their width and height, the number of vertical sections, the diameter of the bars with which they are made, and their spacing.
Both the diameter and the number of vertical sections and the spacing between stirrups may alter along the beam: in general, diameters are greater and the numbers of vertical sections largest, with the shortest spacing, close to the beam end rather than in the centre. By way of example, and without limitation, standard reinforcement for a reinforced concrete beam may have several top lengthwise bars, several bottom lengthwise bars of the same length as the so-called strengthening bars, and the stirrups, which may be of several vertical sections of variable width, height and spacing. The bar diameter may be any of those in the usual range for construction though, normally, the upper bars are between 6 and 12 mm and the lower bars between 8 and 25 mm, while the stirrups are between 6 and 12 mm.
Beam reinforcement is dimensioned to meet the conditions imposed by the design calculation also taking account of the construction of its component elements. The design of the stirrups, whether in manual equipment or automatic programmable machines, means that the upper and lower horizontal sections of the transversal reinforcements must have the same diameter and spacing as the vertical sections when, for calculation purposes, they can be of a smaller diameter and significantly more spaced than the vertical sections. The technology familiar until now is thus rendered obsolete, given the novelty of this invention described below. Nothing similar has been known until now and it involves major savings of materials and the possible prefabrication of reinforcement, with great space saving. Therefore, in this method, we propose dimensioning of the vertical and transversal reinforcement and of the upper and lower horizontal sections independently, to provide a significant saving in the materials used to manufacture reinforcements.
The concept of independent dimensions for the vertical and horizontal sections of the transversal reinforcement leads into a description of the main components of this invention.
The main elements of the reinforcement for reinforced concrete beams and pillars based on the foregoing dimensioning procedure are: a sub-reinforcement known as the grill, and the upper and lower horizontal bars of the transversal reinforcement.
The reinforcement is designed as a set of sub-reinforcements each comprising a top and bottom bar welded together or attached by any other means by a number of vertical sections. Known as grills, these sub-reinforcements are linked by the top and bottom horizontal sections of the transversal reinforcement, which is generally of a smaller diameter than the vertical sections of the grills, and more spaced in the case of reinforcement for reinforced concrete beams.
The reinforcement is completed with the bottom bars, some of which are as long as the beam and others which are shorter than the beam: these are the so-called strengthening bars. See figures 1 and 2 for a better understanding of the foregoing.
The concrete beam reinforcement comprises the grills 1-1'-1R, 2-2'-2R, and 3-3'-3R which have a top bar and a bottom bar and several vertical sections joined by the upper horizontal bars Hs and lower horizontal bars Hi, along with two bottom bars the same length as the beam, nos. 4 and 5, and a bottom strengthening bar -6- of length l.
With this design for the beam reinforcement, the vertical sections of the transversal reinforcement are made independent of the horizontal sections, and the diameter and spacing of the vertical sections can be combined to optimize the use of the materials. Moreover, because the horizontal bars Hs and Hi are independent of the vertical sections, they can be of a smaller diameter and more separated, with the resulting saving of materials.
This shows how the reinforced concrete beam reinforcement consists of sub-reinforcements (grills) with long and short reinforcing longitudinal bars, and top and bottom transversal bars. The construction system based on the above dimensioning method eliminates the traditional stirrups, and the notion of sub-reinforcement (grill) emerges.
Sub-reinforcement (grill) is the link between a top and bottom lengthwise bar by means of several vertical transversal bars (see Figs. 3 or 4 by way of illustration, without limitation).
With the adequate spacing of the number of grills required according to the calculation to withstand shear strength, the width of a beam, B, is obtained. A grill of height H and Length L can be used to form beams of any width. In addition, the diameters of the top and bottom bars of the grill and the transversal bars vary only slightly for beams of Length L, meaning that the grills can be prefabricated, taking up very little space.
The upper and lower horizontal bars of the transversal section are the other necessary elements for the construction of the beams; their length normally varies by 5 cm steps, as the width of the beams and pillars and the usualy diameters are 6 and 8 mm. They can thus be made in high-performance automatic straightener-cutter machinery and stored in very limited space. This invention proposes the concept of constructing the reinforcement for reinforced concrete beams and pillars using pre-fabricated elements stored in a small space and making it possible to combine them to form all types of reinforcement for reinforced concrete beams and pillars quickly and economically. These basic components are as follows: the sub-reinforcement known as the grill, and the top and bottom bars of the transversal reinforcement. By adding to these components the free lengthwise bars which can be the same length as or shorter than the beam it is possible to make any reinforcement for reinforced concrete beams and pillars, taking advantage of the savings of materials which this dimensioning method allows, as well as the versatility, speed and space-saving afforded by pre-fabrication.
In a variant of the so-called grill sub-reinforcement, as in figures 7 and 8, the transversal bars are placed over rather than between the lengthwise top and bottom bars and are welded together or joined by any other means.
This modification facilitates automatic production of the sub-reinforcement or grill.
A further improvement to this variant consists of the replacement when convenient for the calculation or production of the top and bottom transversal reinforcement by the sub-reinforcement or grill defined in figures 7 and 8, making it possible to construct the reinforcement for reinforced concrete beams and pillars as indicated in figures 5 and 6, by a combination of sub-reinforcement (grills) 1-1'-1R, 2-2'-2R, and 3-3'-3R placed in the vertical position, with other sub-reinforcement (grills) 4-4'-Hs -5-5'-Hi placed horizontally and welded together or joined by any other means. By way of example and without limitation, the reinforcement is completed with the long free bottom bars 6 and 8 and the short free bar 7 (see figures 5 and 6).
Another variant of the sub-reinforcement known as grills in figures 9 and 10 is differentiated from the grills described above in that the transversal bars are joined to the longitudinal bars by welding or by any other means, and all or some of them are bent over the longitudinal bars to form a hook.
This modification provides greater strength to the connection of the transversal bars, with the lengthwise components of the sub-reinforcement (bars) where and when necessary to the calculation: the strength of the welding is added to that of the hook in its anchoring in the concrete.
These sub-reinforcements, with all or part of the transversal bars ending in a hook, can be used vertically (figures 9 and 10), or horizontally at the top or bottom (figures 11 and 12), or combined with similar or different sub-reinforcement such as those described above, or else with the horizontal transversal reinforcement also described.
By way of illustration and without limitation, a reinforced concrete beam reinforcement is drawn (figures 13 and 14) combining the sub-reinforcement described according to figures 9 and 10, in the vertical position 1-1'-1R, 2-2'-2R, and 3-3'-3R, with the sub-reinforcement described according to figures 7 and 8 placed horizontally at the bottom 4-4'-Hi and with the free horizontal bars in the top horizontal position Hs.
The reinforcement is completed, by way of example and without limitation, with the bottom lengthwise bars 5 and 6.

Claims

A method for dimensioning reinforcements for reinforced concrete beams wherein calculation of the vertical sections of of the transversal reinforcement is made independent of that of the top and bottom horizontal bars, providing major savings of materials.
A procedure for the construction of reinforcements for reinforced concrete according to claim 1, which replaces traditional stirrups with independent vertical and horizontal bars which may thus be of different diameters and spaced at different distances along the length of the reinforcement.
A procedure for the construction of reinforcements for reinforced concrete according to claims 1 and 2, which defines the top and bottom horizontal bars of the transversal reinforcement which may be valid for any reinforcement of beams or pillars made of reinforced concrete of width B, and can be produced in automatic machinery and stored in very limited space.
A procedure for the construction of reinforcements for reinforced concrete acording to claim 2, which defines sub-reinforcements known as grills formed by a top and bottom bar of any diameter linked together by welding or by any other means, and vertical bars of any diameter separated by spaces which may vary along the reinforcement. The length of these transversal bars is defined by the height of the reinforcement.
A procedure for the construction of reinforcements for reinforced concrete according to claims 3 and 4, wherein reinforcement is formed with a number of sub-reinforcements (grills) defined in the calculation, and suitably separated. Said sub-reinforcements are joined by the top and bottom transversal bars defined in claim 3, spaced along the reinforcement as required according to the calculation. The reinforcement is completed with the addition and attachment, by welding or some other means, of the top free lengthwise bars to the top transversal bars, and the free, long and reinforcing bars to the bottom transversal ones.
A procedure for the construction of reinforcements for reinforced concrete as set forth in claims 2 and 4, wherein sub-reinforcements, known as grills, are defined in the form of two lengthwise bars, one at the top and the other at the bottom, on which transversal bars are fitted, attached to the former by welding or by any other means.
A procedure for the construction of reinforcements for reinforced concrete as set forth in claims 1, 2, 3, 4, 5 and 6, wherein the reinforcements are made by a combination of sub-reinforcements placed vertically, with other sub-reinforcements placed horizontally, and joined by welding or by any other means. The reinforcement is completed with the addition and attachment, by welding or by any other means, of the top free lengthwise bars to the top horizontal sub-reinforcement, and the bottom long free and reinforcement lengthwise bars to the bottom horizontal sub-reinforcement.
A procedure for the construction of reinforcements for reinforced concrete as set forth in claims 2, 4, and 6, wherein the transversal bars of the sub-reinforcement or grill are attached by the longitudinal bars by welding or by any other method, and all or some of them are bent over the longitudinal bars to form a hook, and can be employed either vertically or horizontally.
A procedure for the construction of reinforcements for reinforced concrete as set forth in claims 1, 2, 3, 4, 5, 6, 7 and 8, wherein said reinforcements for reinforced concrete beams and pillars can be made using any combination of the sub-reinforcements described in the previous claims, with free horizontal bars as described in claim 2, completed with the top and bottom lengthwise bars.
A procedure for the construction of reinforcements for reinforced concrete as set forth in claims 1, 2, 3, 4, 5, 6, 7, 8 and 9, proposing the pre-fabrication of the sub-reinforcements (grills) and of the top and bottom transversal bars, which can thus be stored in a more limited space than that taken up by the reinforcements they can be used to construct with.
A procedure for the construction of reinforcements for reinforced concrete as set forth in claims 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10, wherein the reinforced concrete beam and pillar reinforcements are designed using the dimensioning method in claim 1 and the construction methods in claims 2, 3, 4, 5, 6, 7, 8 and 9, making it possible to construct the reinforced concrete beam and pillar reinforcements with more economical use of the materials, and more quickly, thanks to the versatility and generic nature of the elements described in claims 2, 3, 4, 5, 6, 7, 8 and 9.