CZ31089U1 - A prestressing non-metallic composite tool for transverse reinforcement of historic wall masonry - Google Patents

Description

Technical field

The technical solution relates to a prestressing device consisting of prestressed composite bars and special anchoring elements for lateral reinforcement of the bearing masonry of higher thicknesses.

BACKGROUND OF THE INVENTION

Due to insufficient tensile strength of masonry, the bearing masonry of buildings, especially historical ones, is often disturbed by local tensile cracks, resp. a cluster of cracks of smaller widths affecting the integrity of the masonry and reducing its mechanical properties.

The most common way of reinforcing such damaged masonry is to remediate, for example, by means of welded anchored mesh, so-called KARI net, on which is subsequently carried out reinforcing layer of lime-cement or cement mortar. This solution is accompanied by a number of serious physicochemical problems, such as an increase in diffusion resistance, which can lead to the deposition and crystallization of salts in the area of the contact gap and to a gradual disruption of the contact. Different rheological and mechanical properties, such as shrinkage, creep, etc., reinforced masonry and reinforcing cement, respectively. welded mesh reinforced lime-cement layers cause the integrity of the wall to be repaired. As a result of these effects, the contact joint of the reinforcing layer and the adjacent masonry usually break after a certain period of time, preventing loss of functionality and subsequent destruction of the remediation measure. Another possibility is the area grouting, resp. microinjection with suitable grouting substances - polymers, cement suspensions, etc., additional insertion of reinforcement stirrups into bed joints, concrete casting, event. reinforced with steel bandage.

The essence of the technical solution

The above-mentioned drawbacks of the solution are eliminated by the technical solution consisting of reinforcing the masonry with special additionally prestressed transverse anchors based on composite rods, for example of carbon or plastic. glass fiber.

Transversely arranged anchors based on carbon, respectively. The glass composites are formed by bending rods of circular profile with an outer diameter smaller than the diameter of the bores made over the entire thickness of the masonry wall so that the cross anchors of carbon or glass composite can be inserted freely into the drilled holes in the masonry wall. Both ends of the cross anchor rods are anchored by means of special outer sleeves and anchor sleeves. The purpose of the outer sleeves is to strengthen the masonry at the location of the circular hole larger than the diameter of the switch bars and to allow reliable anchoring of the so-called anchor sleeve. The anchor sleeves are equipped with an end “collar”, which by their conical shape and adjustment of the end parts to sub-segments and internal flaps ensure contact with masonry and transfer of pressure bias into masonry.

The anchor sleeves are made of the same material as the prestressing rods, eg on the basis of composites of carbon or carbon dioxide. glass fiber and epoxy resin.

Special transverse anchors for post-tensioning can be placed as individual reinforcement elements or as a special feature. placed in rows or. chessboard, in places under the support of beams, beams and the like so as to achieve the necessary reinforcement of the masonry in the transverse direction.

Anchor sleeves and prestressing rods made of carbon fiber composite materials, resp. glass fibers are made of carbon fibers with a thickness of 0.25 to 0.32 mm with a tensile strength of 3000 to 4000 MPa, a modulus of elasticity of 200 to 250 GPa, a maximum tensile strain of 1.5 to 1.9%, a density of 1.5 to 2 g / cm ³ and a weight of 600 to 700 g / m ² . glass fibers with a thickness of 0.18 to 0.38 mm with a tensile strength of 2500 to 3500 MPa, a modulus of elasticity of 65 to 80 GPa, a maximum tensile strain of 4 to 5%, a density of 2.2 to 2.7 g / cm ³ and a grammage 500 to 1000 g / m ² . In both cases, a two-component epoxy resin is used as the matrix.

-1 CZ 31089 Ul

Said static remediation preserves the shape of the element, does not require demanding covering layers, eg due to thermal bridges and the like, and due to prestressing does not require further transverse deformation of the original masonry to be activated immediately.

The slightly conical modification of the outer surface of the anchor sleeve and of the inner surface of the outer sleeve makes it possible to achieve the necessary clamping of the switching rod in the anchor sleeve. The biasing device is released after the desired strength of the epoxy injection composition has been reached. Subsequently, the prestressed rod is also shortened so that it does not extend beyond the anchoring element and the masonry face.

Clarification of drawings

The proposed technical solution will be elucidated in more detail by means of the exemplary embodiments shown in the attached drawings, where:

Giant. 1 Placement of additionally pre-tensioned carbon or anchoring cross anchors. glass fibers in pre-drilled holes in the masonry.

Giant. 2 Details of technical modifications of special composite - carbon or glass hollow conical anchoring elements, in section.

Giant. 3 Schematic diagram of additionally prestressed transverse composite anchor, end composite anchoring elements and transverse anchor prestressing.

Examples of technical solutions

Fig. 1 shows an exemplary embodiment of transversally fastening a larger wall thickness 1 (t> 600 mm) by means of composite rods 2 based on carbon or glass fibers 10 to 15 mm in diameter, placed in pre-drilled holes 3 15 mm in diameter The outer anchor sleeves 4 with a conical bore 5 are glued into the drilled holes 3 with the epoxy adhesive. 20 to 25 mm equipped with an end collar 7 with a thickness of min. 5 mm, an aperture 8 having a diameter of 10 to 15 mm, four notches 9 dividing the circular profile of the anchoring elements 6 into four parts and injection holes 10 having a diameter of 2 to 4 mm.

Fig. 2 shows an exemplary embodiment of a special composite carbon or glass hollow conical outer sleeve 4 with a conical bore 5 with a specially adapted inner 11 and outer 12 surface by radial grooving and inner anchoring element 6 by an end collar 7, bore 8 for extending the composite rod 2. a specially treated inner surface 13 to provide the desired adhesion and injection holes 10.

FIG. 3 shows an exemplary embodiment of transversal prestressing of a larger brick wall I of greater thickness by means of composite bars 2 located in the openings 3 and special composite hollow conical outer sleeves 4 and inner anchoring elements 6 biased to a desired value by a special switching device 14.

In the preformed circular holes 3 in the masonry, in the first stage, the outer sleeves 4 of composite materials are anchored in the hole 3 in the masonry by means of an epoxy resin, respectively. 2. After reaching the required strength of the epoxy resin, the polymer cement blends are mounted to allow collision-free insertion of the composite switching rod. A special composite compound is inserted into the composite switching rod 2 so that it passes over the entire thickness of the masonry. The inner anchoring element 6 with a slightly conical outer surface and an inner diameter bore corresponding to the diameter of the switching rod 2 is successively pushed on one side mechanically on the outer anchor sleeve 4. The slightly conical adjustment of the outer surface of the anchor element 6 and the inner surface of the outer sleeve 4 The same procedure is repeated on the other side of the masonry on which the prestressing device is mounted. The inner anchoring element 6 is pushed into the outer sleeve 4 after reaching the desired biasing force. The inner anchoring elements 6 are min. 2/3 of the total length of the sleeves provided with notches 9 dividing the circular profile of the anchoring element 6 into sub-segments. All contact surfaces, i.e. between the outer sleeve 4 and the inner element 6 and between the inner element 6 and the switch

-2GB 31089 UL bars 2 are specially coated to increase the shear strength of the contact joints. The anchor sleeves are provided at the points between the individual segments of the slightly conical annular portion with openings 10 for injecting the contact surfaces between the anchor sleeve segments and the composite prestressed rods 2 and the circular opening 3 in the wall. The biasing device is released after the desired strength of the epoxy injection composition has been reached. Consequently, the prestressed rod 2 is also shortened so that it does not extend beyond the anchoring element and the masonry face.

Industrial applicability

The pre-stressed non-metallic composite fixture according to the proposed technical solution allows for additional prestressing of bearing walls of larger thicknesses and is usable in the building industry.

Claims (10)

PROTECTION REQUIREMENTS A prestressing non-metallic composite fixture for transversally reinforcing historic masonry walls (1) of greater thickness, characterized in that it consists of a switching rod (2) at the ends of which are inner anchoring elements (6) with an outer surface corresponding to the inner opening of the outer anchor sleeves. (4), which can be placed in the openings (3) in the wall (1). The bias-free non-metallic composite fixture according to claim 1, characterized in that the switching rod (2) is provided at both its ends with roughening radial grooves to secure the connection with the inner anchoring elements (6). Prestressing non-metallic composite fixture according to claim 1 or 2, characterized in that the outer anchor sleeve (4) is on its outer surface (12) at the masonry contact point and on its inner surface (11) at the inner anchorage contact point (11). element (6) conical towards the central part of the switching rod (2). 4. Pre-stressing non-metallic composite! the device according to any one of the preceding claims, characterized in that the inner anchoring element (6) is conical on its outer surface at the point of contact with the outer anchoring sleeve (4) towards the central part of the switching rod (2). Prestressing non-metallic composite fixture according to any one of the preceding claims, characterized in that the inner anchoring element (6) has an inner contact surface (13) provided with roughening radial grooves to ensure a reliable connection with the switching rod (2). Prestressing non-metallic composite fixture according to any one of the preceding claims, characterized in that the inner anchoring element (6) is provided with openings (10) for grouting the contact surfaces between the inner anchoring element (6) and the outer anchoring sleeve (4). (2) and masonry walls (1). Prestressing non-metallic composite composition according to any one of the preceding claims, characterized in that at least one part selected from the group of an inner anchoring element (6), an outer anchor sleeve (4) and a switching rod (2) is made of carbon-based composites. / or glass fiber and epoxy resin. The bias-free non-metallic composite fixture according to any one of the preceding claims, characterized in that the outer anchor sleeves (4) are glued into the openings (3). Prestressing non-metallic composite fixture according to any one of the preceding claims, characterized in that the inner anchoring element (6) is provided on its surface with at least three longitudinal notches (9). -3EN 31089 Ul Prestressing non-metallic composite fixture according to any one of the preceding claims, characterized in that the inner anchoring element (6) is provided with a collar at its outer end.