RU2578133C1 - Method of attachment of stone walls of the building - Google Patents

Abstract

FIELD: building.

SUBSTANCE: invention can be used for the repair, strengthening and reconstruction of buildings and structures, and more particularly to remedy serious injury and to ensure the spatial rigidity of the stone walls of the building. Stone walls of the existing building strengthened beamed tense belt, which comprises longitudinal and transverse bands in the form of steel girders and adaptations for joints and tension, which consists of the anchor brackets and fixing bolts with tension nuts. Fastening made in view of ensuring the spatial stiffness and bearing capacity without dismantling the existing building constructions exploited.

EFFECT: technical result is to increase the stiffness, strength and deformation characteristics of masonry.

12 cl, 4 dwg

Description

The invention relates to the field of construction and can be used to increase the strength, stability and spatial rigidity of an existing building with severely damaged masonry.

There is a method of reinforcing the fastening of stone walls of a building, including the device of reinforced concrete beam belts along the contour of the walls at the level of the ceiling, by laying them in the gates (see patent RU No. 918408, M. class. - 3 E04G 23/00; E04H 9/02 / Marjanishvili MA, Kostrits A.I. et al. Method for reinforcing brick walls.

The reasons that impede the achievement of the technical result indicated below when using the known method include the fact that in the known method, the use of reinforced concrete beam belts increases the complexity, weight of the walls and the restoration time of the building, the use of formwork complicates the fastening structure and increases material costs.

A known method of attaching stone walls of a building, including the installation of unloading elements in the form of wooden racks with a spacer device, which is located on the inside and outside of the building and is connected by tension bolts, horizontal frame elements are made of wooden beams, and horizontal stiffeners are made in the form of longitudinal , transverse and intersecting strands (see patent RU No. 2196868, IPC - 7 E04G 23/100 / Ilyin N.A., Kuznetsov A.S. Method for reinforcing stone structures of a building. Declared SGASU 10.03.2000; publ. 01.20.2003 ; By l No. 2) [2].

The reasons that impede the achievement of the technical result indicated below when using the known method include the fact that in the known method, the use of wooden fasteners reduces the class of structural fire safety of the building walls, the use of a complex design of fastening stone walls increases the complexity of the work, their cost and building restoration time.

A known method of attaching stone walls of a building, including the construction of outside the outer walls of a metal or reinforced concrete frame, rigidly connected in nodes to the entire height around the building with a gap relative to the walls; horizontal stiffening belts are arranged in the levels of ceilings around the entire perimeter, fixing them on the walls of the building through the through holes with bolted connections (see RU patent No. 2274718, IPC E04G 23/00 (2006.1) / Belov MV, Raevsky A.N A reconstruction method with reinforcing the building along the entire perimeter, Declared May 25, 2004, published April 20, 2006; Bull. No. 8) [3].

The reasons that impede the achievement of the technical result indicated below when using the known method include the fact that in the known method, the use of a complex reinforcement structure increases the consumption of materials, for example steel, for the manufacture of a spatial frame, increases the complexity, time of restoration of the building and material costs.

The closest technical solution to the invention in terms of features is a method of fastening stone walls of a building, which includes installing fastening elements of stone walls with a tensile belt in the form of longitudinal and transverse steel ties with a device for tensioning them (see Recommendations for strengthening stone structures of buildings and structures. - M .: Stroyizdat, 1984. - 36 pp. (Wall fastening with tensioned belts; paragraphs 3.1–3.5, Fig. 6, p. 21–22)) [4] - taken as a prototype.

The reasons that impede the achievement of the technical result indicated below when using the known method adopted as a prototype include the fact that in the known method, steel bands которые 20 ÷ 38 mm are taken, which are pulled by shrink couplings. This method of fixing the stone walls of a building is unreliable and does not significantly increase the spatial rigidity of badly damaged stone walls; the inclusion of the elements of the prestressed belt in the work of severely damaged stone walls is not complete, the control of the tension of the elements of the prestressed belt is difficult.

EFFECT: increase of operational reliability and growth of spatial rigidity as a result of fastening a badly damaged building; restoration of the integrity of the joint work of interconnected walls of the building, increasing the reliable inclusion of the beam tension belt in the work of the stone walls of the building, increasing the stiffness, strength and deformation characteristics of masonry; increased control of the tension of the runs of the beam tensile belt, ensuring the closure of open cracks in the stone walls; reduction of labor costs and steel consumption for the manufacture of fasteners, increase of indicators of profitability, durability and class of constructive fire safety of the building walls.

The specified technical result is achieved by the fact that the proposed method of fastening the stone walls of the building, including the installation of the longitudinal and transverse elements of the prestressed belt and devices for their tension, the peculiarity is that at first they carry out technical inspection and verification calculations of the damaged walls of the building for strength, then design and manufacture elements of a prestressed belt in the form of beam runs, equipping from one end with a support plate with holes for mounting bolts, and install them on and at one level along the height of the walls of the building; the junction of the longitudinal and transverse beam runs of the prestressed belt is performed from the anchor corner and the fixing bolts, equipping them with tension nuts; the longitudinal and transverse beam runs of the pre-tensioned belt are installed at the floor level of the building with a working gap between the mating surfaces of the support plate of one beam run and the flange surface of the anchor corner of the adjacent beam run, then, while tightening the tension nuts of the fixing bolts of the articulation units, they produce tension longitudinal and transverse beam runs of the prestressed belt along the entire contour of the building, carrying out its volumetric compression.

The longitudinal and transverse beam runs of the prestressed belt are made in the form of a channel of lightweight steel or lightweight steel profile.

The supporting plates of each beam run of the prestressed belt are connected to the walls and shelves of the beam runs, welding by welding, based on the amount of traction from the mounting bolts.

The width b _ys , mm, and the height h _ys , mm, of the anchor angle are respectively taken equal to b _ys = b; h _ys = h-2 · δ; where b and h are the width and height of the corner shelf; δ is the thickness of the corner flange, mm.

The size of the working gap Z, mm, between the mating surfaces of the base plate and the flange of the anchor corner is determined by the algebraic expression (1):

where Z is the size of the working gap, mm; L _min - the length of the transverse run, mm; σ _st is the tensile stress in the run section from traction, MPa; E _s is the modulus of elasticity of steel, MPa.

The fixing bolts are located momentlessly relative to the centers of gravity of the cross-sections of the articulating beam runs of the prestressed belt. To prevent loosening of the tension nut under load, the mounting bolts are equipped with locknuts and elastic washers.

The maximum allowable tensile force (N _{s, max} , kN) in the beam tensioned belt is determined by the algebraic expression (2):

where b is the thickness of the working section of the stone wall, cm; L is the length of the stone wall, cm; R _sg - masonry shear resistance, MPa (kgf / cm ² ).

The beam runs of the prestressed belt along the height of the building are installed first from the bottom of the wall, they pass to each subsequent belt after tensioning the previous one. Tension girders are installed in recesses carved in the stone walls of the building.

Work on fixing the walls of the building is carried out regardless of the ambient temperature.

In FIG. 1 shows the facade of the building with fixtures of damaged stone walls with beam tensioned belts: 1 - building; 2 - stone wall; 3 - through crack in masonry; 4 - beam tensioned belt, laid outside the wall (node - A); 5 - beam tensile belt (laid in a recess cut in the walls of the building, node - B).

In FIG. 2 shows the building plan, section AA, with the fastening of the stone walls with beam tensioned belts: 1 - building, 2 - stone wall, 3 - through crack in masonry, 4 - beam tensioned belt laid from the outside of the wall (node - A) ; 6 - longitudinal beam run.

In FIG. 3 shows the interface unit of the longitudinal and transverse runs of the beam tensioned belt, the first version (the anchor corner is closely connected to the run): 2 - a stone wall; 6 - longitudinal beam run; 7 - transverse beam run; 8 - base plate; 9 - anchor corner; 10 - shelf anchor corner; 11 - stiffener of the anchor corner; 12 - a fixing bolt; 13 - a tension nut; 14 - elastic washer; Z ₁ ; Z ₂ - working clearances.

In FIG. Figure 4 shows the assembly unit B of the longitudinal and transverse beam runs of the prestressed belt, the second version (the anchor corner is inserted floating during installation of the runs: 2 - stone wall; 6 - longitudinal beam run; 7 - transverse beam run; 8 - base plate; 9 - anchor corner; 10 - shelf of the anchor corner; 11 - stiffener of the anchor corner; 12 - fixing bolt; 13 - tension nut; 14 - elastic washer; Z ₂ - working clearance.

Information confirming the possibility of implementing the proposed method to obtain the above technical result

An example of a specific implementation. Inspection of the existing building revealed: 3-storey building with a size of 12 × 18 m in plan; the thickness of the brickwork of the walls is 64 cm; masonry with a network of parabolic cracks expanding upward and inclined to the edges of the building; masonry mortar grade M-35, the calculated masonry resistance to a slice of 0.3 MPa (3 kgf / cm ² ); mounting runs of lightweight channel channels No. 18; base plates of steel plate 10 mm; anchor corners from a rolling profile of 70 × 70 mm; mounting bolts ⌀ 20 mm (accuracy class B; strength class 8.8).

The stone walls of the building with a thickness of 640 mm are fastened with a tensioned beam with a pair of longitudinal runs - 6 and a pair of transverse beam runs - 7, support plates - 8, an anchor angle - 9, a fixing bolt - 12, tension nuts - 13 and elastic washers - 14.

Runs with a length of L = 18 and 12 m are made of lightweight channels No. 18 with cross-sectional dimensions h × b × d = 180 × 70 × 5.1 × 3.7 mm (here h × b × d is the height, width and thickness of the supporting plates); sectional area A = 20.7 cm ² ; base plates - 8 are made of plate steel with a size of h × b × d = 160 × 65 × 10 mm (here h × b × d is the height, width and thickness of the base plate); anchor angle 9 is made of a different-angled profile — with section dimensions b × δ = 70 × 8 mm (here b × δ is the width and thickness of the shelf), height h = 180 mm, sectional area A ₁ = 10.7 cm ² ; the anchor corner has a stiffening rib - 11 and is equipped with two holes ⌀ 21 mm in one flange of the corner, two fixing bolts ⌀ 20 mm, fixing bolts 12 with a class B hexagon head (normal accuracy), elastic washers 14 with a hole diameter d ₁ = 21 mm ; tightening nuts 13 high hexagonal (H = 16 mm) accuracy class In thread diameter d = 20 mm.

The beam tension belt is closed along the contour of the building and installed in the plane of the basement with a recess in the brick wall, thickness B = 640 mm, the recess in the wall has dimensions h ₁ × b ₁ = 190 × 80 mm (here h ₁ × b ₁ is the height and depth of the recess carved into the wall).

The maximum allowable force in the prestressed belt is determined by the algebraic expression (2):

where N _{T, max} - the maximum allowable force in the mounting bolts of the joint assembly, MPa; R _sg — masonry shear resistance, MPa; L is the length of the transverse run of the beam tensioned belt, cm; In _mustache - the thickness of the stone wall, truncated recess, cm (In _mustache = Bb ₁ = 64-8 = 56 cm).

When the grade of the masonry mortar is M = 35, the design shear resistance is R _sg = 0.3 MPa (3 kgf / cm ² ), the length of the transverse beam run L _mjn = 1200 cm and the design thickness of the truncated stone wall is V _must = 56 cm, the greatest allowable force in a prestressed beam run equal to

N _{T, max} = 0.15 · 3 · 1200 · 56 = 30 240 kgf ≈30 t.s.

2 fixing bolts ⌀ 20 mm are structurally adopted, the cross-sectional area of the bolts A _bn = 2 · 3.142 = 6.28 cm ² ; for bolts of strength class 8.8, tensile strength R _bt = 400 MPa (4000 kgf / cm ² ) is the calculated force in bolts N _b = A _bn · R _bt = 6.28 · 4000 = 25140 kgf≈25 t.s. < 30 t.p.

The tensile stresses in the cross-sectional run

σ _races = N _b / A = 25140 / 20.7 = 1215 kgf / cm ² (121.5 MPa).

Based on strength: apply the anchor angle in the form of a segment of the angle profile b × b × δ = 100 × 100 × 8 mm; e = 55 mm; (here b, δ, e are, respectively, the width and thickness of the shelf, the distance from the pick to the center of the hole in the corner); the estimated length of the weld of the flange of the anchor angle lω≥30 mm, accepted lω = 80 mm; the length of the anchor angle l _ug = h = 180 mm; the anchor angle is reinforced with a stiffener 8 mm thick.

The working gap is calculated by the algebraic expression (1):

The introduction of the fastening elements into the work is as follows: longitudinal and transverse runs of the beam belt are made in the workshops, on the ends of which the supporting plates 8 are installed, an anchor angle 9 is welded to one of the supporting plates, two holes ⌀ 21 mm are drilled on the other for fixing bolts 12 .

Then, the longitudinal and transverse beam runs of the prestressed belt are laid in a sash, passing the fixing bolts 12 into the holes of the anchor angle 9, the tensioned joints are pulled by the tension nuts 13, creating a working gap Z = 7 mm between the support plate 8 and the shelf of the anchor corner 9. The tension of the runs is carried out simultaneously by tightening the tension nuts 13 along the entire contour of the beam tensioned belt laid in a recess cut in the walls of the building 5, removing the working gap between the ends of the girders. This ensures the tension of the fastening elements.

The application of the proposed method of fixing the stone walls of the building allows to improve the quality indicators: the fastening elements are easy to manufacture and install due to the rational use of rolled metal, the minimum number of parts and the absence of welding work at height; multi-purpose fastening device, since it simultaneously unloads and corrects the stone walls of the building, as well as compresses the masonry with a beam belt; the mount is reliable during its operation, possessing the necessary rigidity and bearing capacity.

The proposed fastening was used in the strengthening and reconstruction of construction projects in Samara (2010-2014).

Information sources

1. Patent RU No. 918408, M. Cl. - 3 E04G 23/00, E04H 9/02 / Mardjanishvilli M.A., Kostrits A.I. other. A method of reinforcing brick walls. Claim 10.22.79, publ. 04/07/82; Bull. No. 13.

2. Patent RU, No. 2196868 MPK-7 E04G 23/00 Ilyin N.A., Kuznetsov A.S. The way to strengthen the stone structures of the building. Claim SSASU 10.03.2000; publ. 01/20/2003; Bull. No. 2.

3. Patent RU No. 2274718, IPC E04G 23/00 (2006.1), Belov M.V., Raevsky A.N. The method of reconstruction with the strengthening of the building around the perimeter. Claim 05/25/2004, publ. 04/20/2006; Bull. No. 8.

4. Recommendations for strengthening the stone structures of buildings and structures. - M.: Stroyizdat, 1984. - 36 p. (p. 21-22, Fig. 6).

Claims (12)

1. The method of fastening the stone walls of the building, including the installation of longitudinal and transverse elements of the prestressed belt and devices for their tension, characterized in that at first they carry out technical inspection and verification calculations of the damaged walls of the building for strength, then design and manufacture elements of the tensile belt in the form of beam equipping runs from one end with a support plate with holes for mounting bolts, and install them at the same level along the height of the walls of the building; the junction of the longitudinal and transverse beam runs of the prestressed belt is performed from the anchor corner and the fixing bolts, equipping them with tension nuts; the longitudinal and transverse beam runs of the prestressed belt before setting them into operation are set at the level of the building floors with a working gap between the mating surfaces of the support plate of one beam run and the flange surface of the anchor corner of the adjacent beam run, then, while tightening the tension nuts of the fixing bolts of the articulation units, they produce tension longitudinal and transverse beam runs of the prestressed belt along the entire contour of the building, carrying out its volumetric compression. 2. The method according to p. 1, characterized in that the longitudinal and transverse beam runs of the prestressed belt are in the form of a channel of lightweight steel. 3. The method according to p. 1, characterized in that the beam runs of the prestressed belt are made of lightweight steel profile. 4. The method according to p. 1, characterized in that the supporting plates of each beam run of the prestressed belt are connected to the walls and shelves of the beam runs, welding by welding based on the amount of traction from the mounting bolts. 5. The method according to p. 1, characterized in that the width b _ys , mm, and the height h _ys , mm, of the anchor angle are respectively taken equal to b _ys = b; h _ys = h-2 · δ; where b and h are the width and height of the corner shelf; δ is the thickness of the corner flange, mm. 6. The method according to p. 1, characterized in that the magnitude of the working gap Z, mm, between the mating surfaces of the base plate and the flange of the anchor corner is determined by the algebraic expression:
Z = L _min · (σ _st / E _s ); where Z is the size of the working gap, mm; L _min - the length of the transverse run, mm; σ _st is the tensile stress in the run section from traction, MPa; E _s is the modulus of elasticity of steel, MPa. 7. The method according to p. 1, characterized in that the mounting bolts are located momentless relative to the centers of gravity of the cross sections of the mating beam runs of the prestressed belt. 8. The method according to p. 1, characterized in that the mounting bolts are equipped with locknuts and elastic washers. 9. The method according to p. 1, characterized in that the maximum allowable tensile force (N _{s, max} , kN) in the beam tensioned belt is determined by the algebraic expression:
N _{t, max} = 0.15 b · L · R _sg ; where b is the thickness of the working section of the stone wall, cm; L is the length of the stone wall, cm; R _sg - masonry shear resistance, MPa (kgf / cm ² ). 10. The method according to p. 1, characterized in that the beam runs of the prestressed belt along the height of the building are installed first from the bottom of the wall, they pass to each subsequent belt after tensioning the previous one. 11. The method according to p. 1, characterized in that the beam runs of the prestressed belt are installed in the recesses carved in the stone walls of the building. 12. The method according to p. 1, characterized in that the fastening of the walls of the building is carried out regardless of the ambient temperature.

Images