Title of Invention

MASONRY CREEP BAR

Abstract

A Masonry Creep Bar is provided for prevention of cracks in mortar joints between RCC structure and masonry work. The said creep bar being made of a metal sheet of selective length and thickness as per site requirements, said metal sheet consisting essentially of a first end and a last end, wherein said metal sheet between the two ends are configured to have four folds of specified fold widths, characterized in that, the first and the second folds are provided with transverse inverted T cuts which when unfolded and turned against their bases, from a series of lugs to hold rigidly the respective folds with the corresponding concrete member in which they are cast.

Full Text

FIELD OF THE INVENTION This invention relates to creep Bar embedded on the bottom of reinforced concrete beams / slabs on one end and the other end is dipped in the mortar cutting across future passage of moisture movement to prevent cracks in masonry - concrete junctions caused due to creep shrinkage. Also, the Creep Bar shall act as a shear bar to resist cracks in the week union of last course of masonry work and the concrete beams / slabs, caused due to thermal stresses. BACKGROUND OF THE INVENTION Multistoried buildings are built with RCC frame structures to build the main frame with RCC columns, beams and slabs and finally erect the conventional brick masonry for external cladding and internal partitions. Such masonry elements are structurally non-load bearing type but are required to perform some basic functions like protecting the interior from adverse weathering effects, identifying the internal spaces, and should have sufficient rigidity to withstand stresses caused due to changes in weather conditions and also due to various indoor activities. With the advancement of technology and improved concrete science the main frames are designed with better care now a day. But the masonry work is still being done with day's old practice as before. This results in a common problem while negotiating the gap between the bottom of a RCC beam or slab and the last course of the brick masonry. Such gaps are, some times, as little as 10mm or less or as big as 50mm or more. The common practice is to fill the gaps with mortar or broken brick packing with mortar. Such mortar joints cannot fill the gaps uniformly and after the creep shrinkage a gap between the concrete member and the masonry work appears. The gaps appear on the surface plasters as continuous or discontinuous horizontal cracks. This may occur in external 2 cladding as well as in internal partition walls. The cracks on external cladding cause two types of problems - aesthetic and weathering. The later is more nagging in a building. In wet weather the water particles find their way through these cracks, accumulate within the masonry work and cause dampness on interior surfaces. Many attempts have been made to remove the defects caused due to creep shrinkages and thermal movement in concrete-masonry junctions. But no prior art teaches effective solution in that respect to ensure better union between concrete and masonry work in RCC frame structures. The existing practice is to cover up the cracks on exterior surfaces caused by the creep shrinkage and thermal movement by stretching a chicken-wire mesh across the junctions of beams and masonry work on external surfaces before plastering. This is a kind of masking work and to some extent, prevents the cracks on surface plaster but the gaps caused by creep shrinkage still remain within the mortar joints between the beams and the last course of masonry. JP02104846A2 describes a method to prevent the generation of a crack by arranging a ring-like RC, steel to the inside of the bottom of a thick peripheral edge of a square floor ,slab provided with a recession to the bottom of the central part there of by surrounding the recession, and straining and fixing. A ring-like PC steel is arranged to the inside of the bottom of a thick peripheral edge of a square floor slab provided with a recession to the bottom of the central part thereof by surrounding the recession. One end of the PC steel is fixed, and the other end is pulled to strain and fix. After that, a weld wire net as a reinforced bar is arranged on the surface of the floor slab and concrete is placed. According to the constitution, compressive force is introduced in the inside of the floor slab and it can be balanced with stress caused by the load of the floor slab by generating eccentric moment. This solution basically deals with floor slabs and union between concrete members while creep bar deals with cracks in concrete -masonry junctions. 3 JP09078756A2 suggests one V type anchor metal fitting to prevent the occurrence of cracks on a surface of an ALC panel in situations of strong wind pressure and negative load applied on the panel. An anchor metal fitting which consists of a horizontal plate and a rising plate and has a cross section tike L character is formed, and anchor nut is welded and fixed at a central position of the rising plate. The length of the anchor metal fitting 1 is more than 2/3 the width of an ALC panel, and the thickness of the horizontal plate is 3.5 to 6.5mm. Furthermore, a rear surface of the horizontal plate of the anchor metal fitting is across four reinforcing bars which are extended in the direction of the length of the ALC panel and is spot-welded through holes for welding which are provided on the horizontal plate. This system seems to be very elaborate and does not match with present invention. Area of application is also different. US20040040249A1 A1 describes a Spacer element for building blocks in a construction unit having arrangement for spacing vertically adjacent bricks in a construction unit. This spacer element comprises a first engagement portion (and a second engagement portion, the first engagement portion is arranged to engage in an upper surface of a building block and the second engagement portion is arranged Jo engage in a lower surface of a second building block. The spacer element comprises two laterally extending arms, which project outwardly from the spacer element. The laterally extending arms support spacer means in the form of spacer, members. The spacer members provide an upper contact surface to contact a brick located above and a lower contact surface to contact a lower brick. The spacer element comprises two support members. The spacer element provides' spacer means which space the next layer of bricks from the lower layer of bricks by a particular distance. As the wall is built vertically upwards further pressure is placed on the support members and the spacer members, which (may cause the lower edges of the spacer members to fracture or shear. The initial spacing distance may be greater than that required and, therefore, as the mortar sets the mortar will not crack as it contracts since the spacing distance between the building blocks also reduces. But the design and 4 constructional features of the element is complicated and the principle of working of the spacer element is entirely different than that of the creep bar according to this invention. The prior art in the category as mentioned above does not provide a solution to use whereby effective prevention of cracks in the junction between RCC work and masonry work caused due to creep shrinkage and thermal movement. To overcome the limitations of the above prior art a r metallic bar is developed which is embedded on the bottom of RCC beam / slab, on one end and the other end is dipped in the mortar cutting across future passage of moisture movement caused due to creep shrinkage and thermal movement. These metallic bars (Creep Bars) run along the entire length of the external beams and on the bottom of a RCC slab at locations where the internal masonry partitions terminate at ceiling. OBJECTIVE OF THE INVENTION The objective of. this invention is to develop a metallic bar with an intention to block such passages of moisture movement caused due to creep shrinkage and also to act as a shear resisting element in cases of thermal movement in RCC columns, beams and slabs. The further objective of this invention is to provide an anti slip key to prevent cracks in the junctions of RCC elements and internal masonry partitions caused due to vibration and thermal movement. 5 STATEMENT OF INVENTION According to this invention, a creep bar is provided for prevention of cracks, in mortar joints between RCC members and masonry work in buildings with RCC frame structures. (The said creep bar is made of a metal sheet of selective length and thickness as per construction requirements. The said metal sheet essentially consisting of a first end and a last end, wherein the metal sheet between the two ends are configured to have four folds of specified fold widths. The said first and second folds are provided with transverse inverted T cuts which when unfolded and turned against their bases, from a series of lugs to hold rigidly the respective folds with the corresponding concrete members in which they are cast. BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS The foregoing aspects and many of the advantages of this invention will become more readily appreciated by following detailed description when taken in conjunction with the accompanying drawings. Fig. 1 Plan view of a four-fold creep bar according to the invention Fig. 2 Three-dimensional view of the creep bar detailed in Fig. 1 Fig. 3 Typical view of creep bar with inverted T cuts. Fig. 4 Plan view of the embodiment of fig 4 with dimensional features of each inverted T cuts. Fig. 5 Creep bar where the first-fold of the bar is opened and aligned inside a form work of an external beam and held in position by cover blocks. Fig. 6 Creep bar after becoming exposed on the bottom of a beam after de-shuttering. Fig.7 Creep bar- where the Third-fold of the bar is opened and pushed out wards to form an angle not more than 135 degree with the second fold before layjng the top course of a masonry work under a beam. Fig. 8 Creep bar in position. 6 DETAILED DESCRIPTION AND PREFERRED EMBODIMENT OF THE CREEP BAR WITH REFERENCE TO DRAWING The assembly according to the invention and various essential components of the creep bar are described below in reference to the accompanying drawings fig.1 to fig. 9 As detailed in Fig. 1 & Fig. 2 of the accompanying drawings, the creep bar (10) according to this invention is made of metal sheet and folded in four folds of specified fold width. The four folds are referred by numerals 1,2,3 and 4 for first, second, third and fourth fold respectively. The length of the creep bar can be made of different dimensions as per convenience for easy handling, transporting, stacking as well as positioning. Preferably, the length may be a meter long and can be lap-jointed at site to negotiate any length. The material of a creep bar i.e. the metal sheet should not react with concrete and at the same time should have a good bondage with concrete. Preferably, the metal sheet is made of galvanized iron (G.I.) sheet. Thickness of the metal sheet for a creep bar may vary according to its place of use. However, since a creep bar acts as a shear plate it should be thick enough to resist the shear force due to thermal expansion of a concrete member or vibration on the masonry caused by forces owing to wind, sound, traffic etc. and thin enough to handle, place in position and unfold at site with the help of a masonry trowel or simple equipments. The thickness of the metal sheet may be in the range of 26 to 30 gauges. 7 The fold width of the four folds of the creep bar may be 20 mm, 20 mm, 15 mm and 4 mm for the first, second, third and fourth fold respectively. Fig 3 illustrates a preferred embodiment of the creep bar with inverted T cuts (5). The inverted T type details are cuts in First and Second Folds which when unfolded and turned against their bases, from a series of lugs to hold rigidly the respective folds with corresponding concrete member in which they are cast. The plan view and dimensional details of the creep bar with inverted T cuts are shown in fig. 4. Fig. 5 to fig. 8 shows the concept of positioning of a Creep Bar with the help of cover blocks (6) in a concrete beam. A first-fold of creep bar is opened and aligned 75mm inside from external surface of a beam and held in position by cover blocks (6). The creep bar becomes exposed on the bottom of the beams after shuttering (7:) are removed. The Third-fold (3) of creep bar (10) is opened and pushed outwards to form an angle not more than 135 degree with the second fold (2) before laying the top course of a masonry work under a beam(8). Fig 8 illustrates the creep bar in position According to the invention it is stated that while filling the gap between the bottom of a beam (8) and the last course of masonry (9) from inside of a building, the mortar shall stop at the creep bar and some mortar shall pass under the third fold of the bar. The gap of the exterior surface can be filled at the time of external plastering (12). Thus the continuity of the creep-shrinkage gap (11) on the sofit of a beam shall be broken by the creep bar. Further, it is envisaged that the projected part of the creep bar help to minimize the creep by holding the mortar in position. The application of this creep bar though primarily devised for buildings with RCC framed structure Wo prevent moisture movement through creep shrinkage gaps 8 the same can also be used as a non-slip key to prevent cracks between old and new concrete or a masonry work terminating at a hardened concrete element. This creep bar is also useful in all types of construction work involving concrete and masonry work. The advantage of this bar is that it works as a blocker in the passage of moisture movement through the continuity of the creep shrinkage gap on the sofit of a beam or slab. The thickness of a mortar joint is one of the factors for creep. The projected part of the creep bar with its non-slip end holds the mortar in position minimizing the thickness of the same at that position. Thus the creep bar also helps minimize the creep shrinkage. The forces like sound, wind and also those generated by foot traffic, indoors activities etc. causing vibration in partition walls in a building dissipate the energy through the weak junctions developing cracks on plaster. In such situations, creep bar shall acts as a key to arrest such vibration. The creep bar according to this invention is of immense use in construction industry particularly in concrete constructions involving RCC frame structure and masonry work. Different embodiments of the invention are possible to achieve the best method of performance and to obtain the effective weather bar of different dimension as stated earlier. It will be understood that skilled persons with many modifications, variations and adaptations may carry out the invention into practice without departing from its sprit in describing the invention for the purpose of illustration. 9 I Claim 1. A creep bar (10) for prevention of cracks in mortar joints between RCC structure and masonry courses during construction, said creep bar being made of a metal sheet of selective length and thickness as per site requirement, said metal sheet consisting essentially of a first end and a last end, wherein said metal sheet between the two ends are configured to have four folds (1,2,3,4) of specified fold widths to form a loop configuration where fold gap of closed loops before second (2) and third fold (3)is widened, characterized in that - said second (2)and third folds(3) are provided with transverse inverted T cuts(5) which when unfolded and turned against their bases, from a series of lugs to hold rigidly the respective folds with a corresponding concrete members in which they are cast. 2. A creep bar as. claimed in claim 1, wherein the metal sheet is made of galvanized iron sheet. 3. A creep bar as claimed in claim 1, wherein the thickness of the metal sheet is in the range of 26 to 30 gauges. 10 4. A creep bar as claimed in claim 1, wherein the thickness of the metal sheet is 28 gauges. 5. A creep bar as claimed in claim 1, wherein the fold width of the four folds (1,2,3,4) of the creep bar is 20 mm, 20 mm, 15 mm and 4 mm for the first, second, third and fourth folds respectively. 6. A creep bar as claimed in claim 1, wherein during casting first-fold (1) of said creep bar is opened and aligned 75mm inside from external surface of a beam and held in position by cover blocks (6). 7. A creep bar as claimed in claim 1, wherein the Third-fold (3)of creep bar is opened and pushed outwards to form an angle not more than 135 degree with the second fold (2)before laying the top course of a masonry works under a beam(8). 8. A creep bar as claimed in claim 1, wherein the creep bar performs as a non- slip key to prevent cracks between old and new concrete or a masonry work terminating at a hardened concrete element. 9. A creep bar substantially as herein described, particularly with reference to the accompanying drawings., A Masonry Creep Bar is provided for prevention of cracks in mortar joints between RCC structure and masonry work. The said creep bar being made of a metal sheet of selective length and thickness as per site requirements, said metal sheet consisting essentially of a first end and a last end, wherein said metal sheet between the two ends are configured to have four folds of specified fold widths, characterized in that, the first and the second folds are provided with transverse inverted T cuts which when unfolded and turned against their bases, from a series of lugs to hold rigidly the respective folds with the corresponding concrete member in which they are cast.

Documents:

00385-kol-2007-abstract.pdf

00385-kol-2007-claims.pdf

00385-kol-2007-correspondence.pdf

00385-kol-2007-description(complete).pdf

00385-kol-2007-form-18.pdf

00385-kol-2007-form-2-1.1.pdf

00385-kol-2007-form-5.pdf

00385-kol-2007-form-9.pdf

0385-kol-2007-description(provisional).pdf

0385-kol-2007-drawings.pdf

0385-kol-2007-form1.pdf

0385-kol-2007-form2.pdf

0385-kol-2007-form3.pdf

385-KOL-2007-ABSTRACT 1.1.pdf

385-KOL-2007-CLAIMS 1.1.pdf

385-KOL-2007-DESCRIPTION COMPLETE 1.1.pdf

385-KOL-2007-DRAWINGS 1.1.pdf

385-KOL-2007-FORM 1-1.1.pdf

385-KOL-2007-FORM 2-1.2.pdf

385-kol-2007-granted-abstract.pdf

385-kol-2007-granted-claims.pdf

385-kol-2007-granted-correspondence.pdf

385-kol-2007-granted-description (complete).pdf

385-kol-2007-granted-drawings.pdf

385-kol-2007-granted-examination report.pdf

385-kol-2007-granted-form 1.pdf

385-kol-2007-granted-form 18.pdf

385-kol-2007-granted-form 2.pdf

385-kol-2007-granted-form 3.pdf

385-kol-2007-granted-form 5.pdf

385-kol-2007-granted-letter patent.pdf

385-kol-2007-granted-reply to examination report.pdf

385-kol-2007-granted-specification.pdf

385-KOL-2007-REPLY FIRST EXAMINATION REPORT.pdf