Continuous force transfer construction method for embedded supporting steel-concrete lintels at rear opening of masonry wall

Abstract

The invention discloses a continuous force transmission construction method of an embedded support steel-concrete lintel for a masonry wall rear opening. The continuous force transmission construction method comprises the steps of construction preparation, support processing, measurement positioning, support embedding, removal of other masonry at a lintel opening, lintel steel bar installation, lintel concrete pouring and wall construction rear opening. The formed lintel is a longitudinal linear continuous steel-concrete lintel, the embedded I-shaped steel arranged at intervals is a transverse reinforced steel rib of the lintel, and the embedded I-shaped steel, the continuous steel reinforcement framework and lintel concrete bear force together. Force transmission is continuous and uniform, construction is fast and safe, quality control is easy and convenient, and long-term performance is stable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of secondary structure rear opening construction, in particular to a continuous force transmission construction method of embedded support steel-concrete overpass beam for rear opening of masonry wall. BACKGROUND

[0002] In the field of building construction, rear opening of wall is a common requirement for modification, especially when the secondary structure (such as masonry wall) is rear opened, an overpass beam needs to be constructed on the upper side of the opening position to bear the upper load.

[0003] For the construction of overpass beam of secondary structure rear opening, the existing construction technology generally does not directly open the overpass beam opening, but cuts and places a support seat one by one, and then pours concrete to form an overpass beam. When constructing, a support seat needs to be placed after cutting each support hole, and the support seats are arranged continuously in the overpass beam opening, and the stress reinforcement perpendicular to the wall can also be bound, and finally the overpass beam structure is formed by pouring concrete to form small overpass beam segments composed of discrete independent structures.

[0004] This technology solves the safety problem of directly opening the overpass beam opening to a certain extent, but still has the following significant defects: 1. Discontinuous force transmission: the support seats in the overpass beam are not fixed, only relying on the concrete grip, and the support seats are arranged independently, when the upper load of the overpass beam is transmitted downward through the support seats, each support seat transmits force independently, resulting in a "point-to-point" mode of downward transmission of the upper load, and stress concentration and shear concentration are easily generated at the contact between adjacent support seats, resulting in discontinuous joints in the force transmission path of the overpass beam in the permanent use stage, affecting the overall stiffness, and the overpass beam cannot realize the bending resistance as a whole.

[0005] 2. Low construction efficiency: the alternating construction method of cutting and placing support seats one by one has a complex process, takes a long time, and relies on manual work.

[0006] 3. Insufficient construction reliability: there is generally no direct fixing measure between the support seat and the steel bar, which is easy to loosen under the dynamic load of construction, and the safety is low; the force transmission effect depends on the construction precision and quality control, which is actually difficult to completely guarantee in actual construction, and cumulative errors are easily generated, and the construction quality of the installation of the support seat directly affects the forming quality of the final overpass beam, and once the installation elevation of adjacent support seats is inconsistent, etc., it is easy to cause uneven settlement of the overpass beam in the later stage.

[0007] 4. Poor durability: the stress reinforcement perpendicular to the wall is finally combined with the concrete to form multiple independent and side-by-side small overpass beam segments, rather than forming an overall continuous longitudinal overpass beam, and this discrete layout is easy to develop micro-cracks at the joint of the small overpass beam under long-term load, affecting the long-term durability and reducing the durability. SUMMARY

[0008] The application aims to provide a continuous force transmission construction method of embedded support steel-concrete overpass beam of masonry wall rear opening, and solve the problems of discontinuous force transmission, low construction efficiency, insufficient construction reliability and poor durability of the overpass beam in the prior art.

[0009] To achieve the above-mentioned object, the application adopts the following technical scheme: A continuous force transmission construction method of embedded support steel-concrete overpass beam of masonry wall rear opening, and the construction steps are as follows: Step one, construction preparation: the position and size of the overpass beam are designed according to the position and size of the wall rear opening, then the type of embedded I-beam is selected according to the height of the overpass beam; the number of embedded I-beams to be arranged and the interval embedded positions on the overpass beam are designed according to the stress indicators of the type; the position and size of the embedded hole are designed according to the embedded position; Step two, processing support: the embedded I-beam is cut to adapt to the thickness of the wall, and the front and rear sides of the web of the embedded I-beam are symmetrically cut to form installation notches, the installation notches provide continuous steel reinforcement skeleton rooting points, and the cutting depth of the installation notches is determined according to the thickness of the overpass beam longitudinal main reinforcement protection layer; Step three, measurement and positioning: the wall rear opening, overpass beam hole and embedded hole are measured and positioned and marked by setting out; Step four, embedded support: the embedded hole is grooved by using a cutting machine, and then each embedded I-beam is inserted into each embedded hole, at this time the embedded I-beam forms a support seat of the overpass beam upper masonry structure; Step five, removing the remaining masonry of the overpass beam hole: according to the overpass beam setting-out mark, all the remaining masonry outside the embedded hole in the overpass beam range is removed to form the overpass beam hole, and the overpass beam hole is extended to the top and both sides of the wall rear opening; Step six, overpass beam reinforcement installation: the overpass beam longitudinal main reinforcement is integrally welded to the front and rear sides of each web at the installation notch position; then overpass beam stirrups are bound at designed intervals in the overpass beam hole along the length direction of the overpass beam, the overpass beam stirrups integrally connect the front and rear sides of the overpass beam longitudinal main reinforcement to form a continuous steel reinforcement skeleton of the overpass beam, and ensure that the force transmission path is uninterrupted; Step seven, overpass beam concrete pouring: the overpass beam hole is supported and molded, and the overpass beam concrete is poured through the trumpet mouth, the overpass beam concrete is fully wrapped with the continuous steel reinforcement skeleton and the embedded I-beam, and when the strength of the overpass beam concrete reaches 75% of the design strength, the formwork is removed to form the overpass beam; Step eight, construction of the wall rear opening: the overpass beam provides support, and the masonry at the wall rear opening position is removed according to the setting-out.

[0010] In step one, the embedded I-beam further includes an upper flange plate and a lower flange plate, the embedded I-beams are arranged at equal intervals on the continuous steel reinforcement skeleton, and the embedded positions avoid the overpass beam stirrups.

[0011] In step one, the embedded opening is located above the opening area in the wall and is arranged symmetrically. Its width is greater than the width of the embedded I-beam, and its height is greater than the height of the embedded I-beam.

[0012] In step four, the lower flange plate is pressed tightly against the bottom surface of the embedded opening, and the upper flange plate is filled and pressed tightly against the top surface of the embedded opening by a horizontal pad with a width not greater than the width of the upper flange plate and a length not greater than the thickness of the wall.

[0013] In step six, the welding of the longitudinal main reinforcement of the lintel to the web is done by intermittent spot welding, and the length of the weld is not less than 5 times the diameter of the longitudinal main reinforcement of the lintel.

[0014] In step two, the cutting surface where the installation notch on the web plate is located includes three sections: the upper arc transition section, the vertical section, and the lower arc transition section. The cutting depth of the vertical section is greater than the protective layer thickness of the longitudinal main reinforcement of the lintel. The upper arc transition section connects the vertical section with the bottom surface of the outer edge of the upper flange plate, and the lower arc transition section connects the vertical section with the top surface of the outer edge of the lower flange plate.

[0015] In step six, the longitudinal main reinforcement bars of the lintel are set within the vertical section and parallel to the wall surface. The top main reinforcement bars are symmetrically set at the connection between the upper arc transition section and the vertical section on both the front and rear sides, and the bottom main reinforcement bars are symmetrically set at the connection between the lower arc transition section and the vertical section on both the front and rear sides.

[0016] In step one, the width of the lintel opening ranges from 0.5m to 3m, the height of the lintel is not less than 150mm, and there are no fewer than 3 embedded I-beams and embedded openings.

[0017] In step seven, the resulting lintel is a longitudinally linear and continuous steel-concrete lintel, with intermittently set embedded I-beams serving as transverse reinforcing steel skeletons. The embedded I-beams, the continuous steel reinforcement skeleton, and the lintel concrete work together to bear the load.

[0018] Compared with the prior art, the present invention has the following features and beneficial effects: This invention uses I-beams as permanent embedded supports, strictly arranged at design intervals within the lintel. Installation notches are designed on the web, and the longitudinal main reinforcement bars of the lintel are arranged parallel to the wall and spot-welded to the web of the I-beams at the installation notches. The lintel stirrups connect the main reinforcement bars on both sides to form a skeleton. After concrete pouring, a continuously stressed integral steel-concrete lintel is formed. This invention features parallel arrangement of the main reinforcement bars to the wall, resulting in continuous stiffness distribution, uniform shear force distribution, coordinated deformation, and a continuous, uninterrupted force transmission path. The load on the upper part of the lintel is evenly transferred through a "linear distribution" mode, improving stiffness and shear resistance.

[0019] This invention improves construction efficiency by pre-designing a method that involves first intermittently embedding I-beams to bear the upper load, and then chiseling out the lintel openings as a whole, replacing the complex operation of replacing them one by one.

[0020] The I-beams of this invention are standard profiles, which are easy to obtain and reduce costs. The I-beams work together with reinforced concrete, resulting in good overall structural integrity and reducing reliance on the construction accuracy of individual components. The construction quality of the initial I-beam installation has little impact on the forming quality of the lintel.

[0021] This invention forms a longitudinally linear and continuous steel-concrete lintel. The spaced embedded I-beams serve as the transverse reinforcing steel skeleton of the lintel. The embedded I-beams, the continuous steel reinforcement skeleton, and the lintel concrete work together to bear the load, resulting in strong integrity, eliminating discrete support joints, stable performance, reduced crack development, and extended service life. The continuous force transmission mechanism is conducive to maintaining long-term performance and has low maintenance costs.

[0022] This invention is applicable to secondary structural operations with various opening sizes and has high promotional value. Attached Figure Description

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of the measurement and positioning step three of the construction method in this embodiment of the invention.

[0025] Figure 2 This is a schematic diagram of the fourth step of the construction method in this embodiment of the invention, which involves creating an embedded opening.

[0026] Figure 3 This is a schematic diagram of installing an embedded I-beam in the embedded opening during step four of the construction method in this embodiment of the invention.

[0027] Figure 4 This is a schematic diagram of step five, dismantling the remaining masonry, in the construction method of this embodiment of the invention.

[0028] Figure 5 This is a schematic diagram of the installation of the longitudinal main reinforcement bars of the lintel in step six of the construction method of this embodiment of the invention.

[0029] Figure 6 This is a schematic diagram of the installation of lintel stirrups in step six of the construction method of this embodiment of the invention.

[0030] Figure 7 This is a schematic diagram of step seven, pouring concrete for the lintel, in the construction method of this embodiment of the invention.

[0031] Figure 8 This is a schematic diagram of the masonry at the opening location after demolishing the construction wall in step eight of the construction method of this embodiment of the invention.

[0032] Figure 9 This is a magnified view of a partial structure completed in step four of the construction method of this embodiment of the invention.

[0033] Figure 10 This is a magnified view of a partial structure completed in step seven of the construction method of this embodiment of the invention.

[0034] Figure 11 yes Figure 10 Plan view of the central lintel.

[0035] Figure 12 This is a schematic diagram of the cross-section of the lintel showing the connection between the longitudinal main reinforcement and the web plate in step six of the construction method of this embodiment of the invention.

[0036] Figure 13 This is a schematic diagram of the cross-section of the lintel showing the connection between the stirrups and the longitudinal main reinforcement of the lintel in step six of the construction method of this embodiment of the invention.

[0037] Attached reference numerals: 1 - Back opening in wall, 2 - Lintel, 21 - Longitudinal main reinforcement of lintel, 211 - Top main reinforcement, 212 - Bottom main reinforcement, 22 - Lintel stirrups, 3 - Embedded I-beam, 31 - Web, 32 - Installation notch, 321 - Upper arc transition section, 322 - Vertical section, 323 - Lower arc transition section, 33 - Upper flange plate, 34 - Lower flange plate, 4 - Embedded opening, 5 - Lintel opening, 6 - Horizontal pad. Detailed Implementation

[0038] See the examples. Figures 1-13 As shown, a continuous force transfer construction method for embedded support steel-concrete lintels at the rear opening of a masonry wall is described, with the following construction steps: Step 1, Construction Preparation: Design the position and size of the lintel 2 based on the position and size of the opening 1 in the wall. Then, select the model of the embedded I-beam 3 based on the height of the lintel 2. Based on the stress index of the model, design the number of embedded I-beams 3 and their interval embedding positions on the lintel 2. Design the position and size of the embedded opening 4 based on the embedding positions.

[0039] The embedded I-beam 3 also includes an upper flange plate 33 and a lower flange plate 34. The embedded I-beam 3 is arranged at equal intervals on the continuous steel reinforcement cage, and the embedding position avoids the lintel stirrups 22.

[0040] The embedded opening 4 is located above the area of ​​the back opening 1 in the wall and is arranged symmetrically. Its width is greater than the width of the embedded I-beam 3 and its height is greater than the height of the embedded I-beam 3.

[0041] The width of the lintel opening 4 ranges from 0.5m to 3m, the height of the lintel 2 is not less than 150mm, and the number of embedded I-beams 3 and embedded openings 4 is not less than 3.

[0042] In this embodiment, the wall rear opening 1 is located near the right side of the wall, with a design dimension of 1890mm in height and 1370mm in width. The lintel and lintel opening have a design dimension of 1970mm in length and 150mm in height, with both ends of the lintel extending beyond the two sides of the wall rear opening 1 by 300mm on each side. The embedded H-beams 3 are standard No. 14 H-beams with a height of 140mm, an upper flange plate 33 and a lower flange plate 34 with a width of 80mm, and a web plate 31 with a thickness of 5.5mm. Four embedded H-beams 3 are set in the lintel opening 5. The distance between the centerline of the two outermost H-beams and the width edge line of the wall rear opening 1 is 160mm, and the distance between them and the end face of the lintel opening 5 is 460mm. The H-beams are set at equal intervals. Four embedded openings 4 are designed at intervals, with a height of 150mm and a width of 100mm, the same as the lintel opening 5.

[0043] Step 2, processing the support: Cut the embedded I-beam 3 to a length that matches the wall thickness, and symmetrically cut the front and rear ends of the web 31 of the embedded I-beam to form installation notches 32. Installation notches 32 provide anchoring points for the continuous reinforcing bar skeleton. The cutting depth of the installation notches 32 is based on the thickness of the protective layer of the longitudinal main reinforcement 21 of the lintel. During processing, the cut surface of the installation notch 32 on the web 31 includes three sections: an upper arc transition section 321, a vertical section 322, and a lower arc transition section 323. The cutting depth of the vertical section 322 is greater than the protective layer thickness of the longitudinal main reinforcement 21 of the lintel. The upper arc transition section 321 connects the vertical section 322 to the bottom surface of the outer edge of the upper flange plate 33, and the lower arc transition section 323 connects the vertical section 322 to the top surface of the outer edge of the lower flange plate 34. See details. Figure 12 As shown.

[0044] Step 3, Measurement and Positioning: See Figure 1 As shown, the proposed wall openings 1, lintel openings 5, and embedded openings 4 are all measured, located, and marked.

[0045] Step 4, Embedding Support: See Figure 2 As shown, a cutting machine is used to create a groove in the embedded hole 4; see [link / reference]. Figure 3 , 9 As shown, each embedded I-beam 3 is then inserted into each embedded opening 4, at which point the embedded I-beam 3 forms a support for the upper masonry structure of the lintel. The lower flange plate 34 is pressed tightly against the bottom surface of the embedded opening 4, and the upper flange plate 33 is filled and pressed tightly against the top surface of the embedded opening 4 by a horizontal pad 6 whose width is no greater than the width of the upper flange plate 33 and whose length is no greater than the wall thickness. The horizontal pad 6 is generally made of steel plate or iron plate on site.

[0046] Step 5: Remove the remaining masonry at the lintel opening: See Figure 4As shown, following the markings of lintel 2, after removing all the remaining masonry outside the embedded opening 4 within the range of lintel 2, lintel opening 5 is formed. Lintel opening 5 extends all the way to the top left and right sides of the opening 1 behind the wall.

[0047] Step 6, Installation of lintel reinforcement: See Figure 5 , 10 As shown in Figures 11 and 12, the longitudinal main reinforcement bars 21 of the lintel are welded integrally to the front and rear sides of each web plate 31 at each installation notch 32 position; after the construction of the longitudinal main reinforcement bars 21 of the lintel is completed, see [reference needed]. Figure 6 , 10 As shown in Figures 11 and 13, lintel stirrups 22 are tied at the designed intervals within the lintel opening 5 along the length of the lintel 2. The lintel stirrups 22 connect the longitudinal main bars 21 of the lintel on both the front and rear sides into a single unit, forming a continuous steel reinforcement skeleton of the lintel 2, ensuring an uninterrupted force transmission path.

[0048] In this embodiment, the welding of the longitudinal main reinforcement 21 of the lintel to the web 31 is an intermittent spot welding, and the length of the weld is not less than 5 times the diameter of the longitudinal main reinforcement 21 of the lintel.

[0049] See Figure 12 As shown, the longitudinal main reinforcement 21 of the lintel is set within the vertical section 322 and parallel to the wall surface. The top main reinforcement 211 is symmetrically set at the connection between the upper arc transition section 321 and the vertical section 322 on both the front and rear sides. The bottom main reinforcement 212 is symmetrically set at the connection between the lower arc transition section 323 and the vertical section 322 on both the front and rear sides.

[0050] In this embodiment, the longitudinal main reinforcement 21 of the lintel is grade III steel with a diameter of 10mm, the stirrups 22 of the lintel are grade III steel with a diameter of 6mm, and the stirrup tying spacing is 200mm.

[0051] Step 7, Lintel Concrete Pouring: See Figure 7 As shown, formwork is erected for the lintel opening 5, leaving a flared opening for pouring lintel concrete. In this embodiment, the lintel concrete is C25. The entire length of the lintel concrete is covered by a continuous steel reinforcement cage and embedded I-beams 3. When the lintel concrete reaches 75% of its design strength, the formwork is removed to form lintel 2. The final lintel 2 is a longitudinally linear continuous steel-concrete lintel. The spaced embedded I-beams 3 serve as transverse reinforcement for lintel 2. The embedded I-beams 3, the continuous steel reinforcement cage, and the lintel concrete share the load.

[0052] During construction, concrete strength is monitored by using test blocks cured under the same conditions to ensure that the strength meets the standard before demolding and to maintain the safety of the force transmission mechanism.

[0053] Step 8, Opening an opening after constructing the wall: See Figure 8 As shown, lintel 2 provides support for the masonry at the location of the opening 1 after the wall is demolished according to the layout.

Claims

1. A continuous force transmission construction method of a masonry wall with a rear opening embedded support steel-concrete overpass beam, characterized by, The construction steps are as follows: Step one, construction preparation: according to the position and size of the wall hole (1) behind the wall, the position and size of the lintel (2) are designed, then according to the height of the lintel (2), the model of the embedded I-beam (3) is selected; according to the stress index of the model, the number of embedded I-beams (3) to be embedded and the interval embedded position on the lintel (2) are designed; according to the embedded position, the position and size of the embedded hole (4) are designed; Step two, processing support: cutting embedded I-beam (3), so that its length is adapted to the thickness of the wall, and the web (31) of the embedded I-beam is symmetrically cut at the front and back two sides of the end to form the installation gap (32), the installation gap (32) provides the continuous steel reinforcement skeleton root point, and the cutting depth of the installation gap (32) is accurate to the thickness of the protective layer of the lintel longitudinal reinforcement (21); Step three, measurement and positioning: each wall hole (1) to be opened behind the wall, the lintel hole (5) and the embedded hole (4) are measured and positioned and marked with a line; Step four, embedded support: using a cutting machine to groove the embedded hole (4), then inserting each embedded I-beam (3) into each embedded hole (4), at this time the embedded I-beam (3) forms the support seat of the upper masonry structure of the lintel; Step five, remove the remaining masonry of the lintel hole: according to the line mark of the lintel (2), remove all the remaining masonry in the embedded hole (4) except the position of the embedded hole (4) within the lintel (2) to form the lintel hole (5), which extends to the top of the wall hole (1) on both sides; Step six, lintel reinforcement installation: the lintel longitudinal reinforcement (21) is integrally welded to the front and back two sides of each web (31) at the position of each installation gap (32); then the lintel stirrup (22) is bound at the designed interval along the length direction of the lintel (2) in the lintel hole (5), the lintel stirrup (22) connects the front and back two sides of the lintel longitudinal reinforcement (21) into a whole, forming the continuous steel reinforcement skeleton of the lintel (2), ensuring that the force transmission path is uninterrupted; Step seven, lintel concrete pouring: the lintel hole (5) is supported and molded, and the lintel concrete is poured through the horn mouth, the lintel concrete is fully wrapped with the continuous steel reinforcement skeleton and the embedded I-beam (3), and when the strength of the lintel concrete reaches 75% of the designed strength, the formwork is removed to form the lintel (2); Step eight, construction of wall hole behind the wall: the lintel (2) provides support, and the masonry at the position of the wall hole (1) behind the wall is removed according to the line mark.

2. The continuous load transfer construction method of masonry wall opening embedded support steel-concrete beam according to claim 1, characterized in that: In step one, the embedded I-beam (3) also includes an upper flange plate (33) and a lower flange plate (34), the embedded I-beam (3) is arranged at equal intervals on the continuous steel reinforcement skeleton, and the embedded position avoids the lintel stirrup (22).

3. The continuous load transfer construction method of embedded steel-concrete composite beam for masonry wall opening according to claim 2, characterized in that: In step one, the embedded hole (4) is located above the wall hole (1) behind the wall and is symmetrically arranged, its width is greater than the width of the embedded I-beam (3), and its height is greater than the height of the embedded I-beam (3).

4. The continuous load transfer construction method of masonry wall opening embedded support steel-concrete beam according to claim 3, characterized in that: In step four, the lower flange plate (34) is tightly embedded into the bottom surface of the embedded hole (4), and the upper flange plate (33) is filled with a horizontal pad plate (6) with a width not greater than the width of the upper flange plate (33) and a length not greater than the thickness of the wall between the top surface of the embedded hole (4).

5. The continuous load transfer construction method of embedded steel-concrete composite beam for masonry wall opening according to claim 2, characterized in that: In step six, the welding of the longitudinal main reinforcement (21) and the web plate (31) is intermittent spot welding, and the length of the weld is not less than 5 times the diameter of the longitudinal main reinforcement (21) of the lintel.

6. The continuous load transfer construction method of embedded steel-concrete composite beam for masonry wall opening according to claim 5, wherein: In step two, the cutting surface of the mounting notch (32) on the web plate (31) includes three sections, namely the upper arc transition section (321), the vertical section (322) and the lower arc transition section (323), the cutting depth of the vertical section (322) is greater than the thickness of the protective layer of the longitudinal main reinforcement (21) of the lintel, the upper arc transition section (321) connects the vertical section (322) and the bottom surface of the outer edge of the upper flange plate (33), and the lower arc transition section (323) connects the vertical section (322) and the top surface of the outer edge of the lower flange plate (34).

7. The continuous load transfer construction method of masonry wall opening embedded support steel-concrete overpass beam according to claim 6, characterized in that: In step six, the longitudinal main reinforcement (21) of the lintel is arranged in the vertical section (322) and parallel to the wall surface, the top main reinforcement (211) is symmetrically arranged at the connection between the upper arc transition section (321) and the vertical section (322) on the front and rear sides, and the bottom main reinforcement (212) is symmetrically arranged at the connection between the lower arc transition section (323) and the vertical section (322) on the front and rear sides.

8. The continuous load transfer construction method of masonry wall opening embedded support steel-concrete overpass beam according to claim 1, characterized in that: In step one, the width of the lintel hole (4) is 0.5m-3m, the height of the lintel (2) is not less than 150mm, and the number of embedded I-beams (3) and embedded holes (4) is not less than 3.

9. The continuous load transfer construction method of masonry wall opening embedded support steel-concrete overpass beam according to claim 1, characterized in that: In step seven, the formed lintel (2) is a longitudinal linear continuous steel-concrete lintel, the embedded I-beams (3) arranged at intervals are the transverse reinforcing steel bars of the lintel (2), and the embedded I-beams (3), the continuous steel reinforcement framework and the lintel concrete jointly bear the force.

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