Construction method of stepped window roof precast beam

Abstract

This invention discloses a construction method for a stepped precast roof beam with windows. The precast beam includes parallel upper and lower chords, with a precast window installation position in the middle of the upper and lower chords, and truss structures located between the upper and lower chords on both sides. During construction: ① the components of the precast beam are laid out and cut; ② welding is performed, and aluminum alloy windows are installed to complete the factory prefabrication of the beam; ③ the precast beams are transported to the construction site, hoisted and installed one by one, with both ends of each precast beam welded to the roof longitudinal beams, and the top surface of the upper chord flush with the surface of the step above, and the bottom surface of the lower chord flush with the surface of the next adjacent step below. This invention uses a beautifully designed, lightweight, and ingenious precast beam with windows, exhibiting low overall deflection and excellent load-bearing capacity. It is easy to source materials and install quickly and conveniently, meeting the load-bearing requirements of stepped roof beams while also considering the overall aesthetic requirements after installing windows on the stepped roof, significantly shortening the construction period.

Description

Technical Field

[0001] This invention relates to the field of steel structure technology for large-span civil buildings, and in particular to a construction method for a stepped precast roof beam with windows. Background Technology

[0002] In modern-style civil buildings such as exhibition halls, sales offices, art centers, and hotels, some adopt a stepped roof structure to enhance the linearity and rhythm of the architectural form. These buildings typically have a span of 8-18 meters, with each step being 500-1000 mm high. To enhance interior brightness and transparency, long, narrow windows, 4-8 meters long and 200-500 mm high, are often installed within the stepped design. However, existing long windows encounter the following problems during installation: 1) When the steel beam below the long window is a solid-web steel beam, it must be lower than the bottom of the next step, creating a misalignment. This results in a portion of the steel beam extending from below the roof panel being visible from inside the building (see...). Figure 6 As shown in section a), it affects the architectural space effect; if, for aesthetic purposes, the steel beam is set close to the top surface of the next step, the height of the steel beam web is drastically compressed to 300~500mm, at which point the load-bearing capacity of the steel beam cannot meet the load of the roof panel, the equipment on the panel, and the windows; 2) If a whole H-beam is selected, a 4~8m window opening needs to be made in the web of the steel beam to install windows (see Figure 6 As shown in section b), the long window opening will significantly weaken the strength of the steel beam web and the overall load-bearing capacity of the steel beam, making it unable to withstand large loads. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a construction method for stepped precast roof beams with windows, specifically employing the following technical solution:

[0004] The construction method of the stepped precast roof beam with window described in this invention is for the following precast beam, which includes a parallel upper chord and a lower chord, a precast window installation position is provided in the middle of the upper chord and the lower chord, and a truss structure located between the upper chord and the lower chord is provided on both sides of the precast window installation position;

[0005] The construction method for the precast beams includes the following steps:

[0006] The first step is to lay out and cut the various components of the precast beam according to the design drawings;

[0007] The second step is to weld and process the various components of the precast beam according to the design drawings, and then debug and install the aluminum alloy windows to complete the factory prefabrication of the precast beam.

[0008] The third step is to transport the precast beams obtained in step two to the construction site, hoist and install them one by one. Each precast beam is located between adjacent step surfaces. The top surface of the upper chord is flush with the upper step surface, and the bottom surface of the lower chord is flush with the lower step surface. The two ends of the upper and lower chords are welded to the roof longitudinal beams.

[0009] The finished window mounting position is enclosed by an upper chord, a lower chord, and a vertical bar set between the upper and lower chords.

[0010] The vertical members are arranged symmetrically in a pair along the central axis of the upper and lower chords, and a reinforcing member connected to the upper and lower chords is also provided between the vertical members.

[0011] The reinforcing rod is arranged along the central axis of the upper and lower chords and is located on the rear side of the finished window.

[0012] The truss structure consists of vertical web members and diagonal web members. The diagonal web members are arranged between adjacent vertical web members, and the diagonal web members are either continuous diagonal web member structures or parallel diagonal web member structures.

[0013] Both the upper chord and the lower chord are rectangular steel tube structures, and the ends of the upper chord and the lower chord are equipped with sealing plates.

[0014] When the roof longitudinal beam is a hot-rolled H-beam or welded H-beam structure, a vertical groove is provided at the end of the upper chord and the lower chord. A vertical connecting steel plate is provided in the vertical groove. A stiffening rib located between the upper chord and the lower chord is welded to the left and right sides of the vertical connecting steel plate. The stiffening rib and the vertical connecting steel plate are welded to the web of the roof longitudinal beam.

[0015] The construction method for stepped prefabricated roof beams with windows provided by this invention utilizes aesthetically pleasing, lightweight, ingeniously designed prefabricated beams with minimal overall deflection and excellent load-bearing capacity. These beams are readily available, easy to install, and meet the load-bearing requirements of stepped roof beams while also ensuring the overall aesthetic appeal of the roof steps after window installation. This invention manufactures the entire component in the factory before on-site installation, optimizing the construction process and significantly shortening the construction period. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the precast beam described in this invention. Figure 1 .

[0017] Figure 2 This is a schematic diagram of the precast beam described in this invention. Figure 2 .

[0018] Figure 3 This is a schematic diagram of the connection structure between the precast beam and the longitudinal beam of the roof structure made of hot-rolled H-beam or welded H-beam as described in this invention.

[0019] Figure 4 yes Figure 3 Schematic diagram of the slotted structure of the upper / lower chord.

[0020] Figure 5 This is a schematic diagram of the connection structure between the precast beam and the longitudinal beam of the rectangular tube roof described in this invention.

[0021] Figure 6 This is a schematic diagram of a stepped roof with windows, using different structural beams to install windows. Detailed Implementation

[0022] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the scope of protection of the present invention is not limited to the following embodiments.

[0023] like Figure 1 , Figure 2 , Figure 6 As shown in section c, the construction method of the stepped precast roof beam with windows described in this invention is for a precast beam with the following structure, which is set between adjacent stepped surfaces, including a parallel upper chord 1 and a lower chord 2. The top surface of the upper chord 1 is flush with the surface of the previous step, and the bottom surface of the lower chord 2 is flush with the surface of the next step. The total height is in the range of 800-1000mm, the front-to-back width is 150-200mm, and the span is 8-18m, meeting the height requirements for the stepped architectural shape. To reduce the weight of the steel beam and meet the requirements for lightness, the upper chord 1 and lower chord 2 are selected as rectangular steel tube structures, which can be welded rectangular tubes or cold-formed thin-walled finished rectangular tubes, with a preferred thickness of 6-12mm. Furthermore, steel plates are welded to the ends of the upper chord 1 and lower chord 2 as sealing plates 11.

[0024] The ends of the upper chord 1 and lower chord 2 are connected to the roof longitudinal beam M. When the roof longitudinal beam M is a hot-rolled H-beam or welded H-beam structure, coaxial vertical slots 12 are provided at the ends of the upper chord 1 and lower chord 2 (see...). Figure 4 The vertical groove 12 penetrates the sealing plate 11, and a vertical connecting steel plate 13 is provided inside the vertical groove 12. The vertical connecting steel plate 13 is welded to the upper chord 1, lower chord 2 and sealing plate 11 using double-sided fillet weld or single-sided bevel weld. Then, a stiffening rib 14 is welded to the left and right sides of the vertical connecting steel plate 13, located between the upper chord 1 and lower chord 2. The vertical connecting steel plate 13 and the stiffening rib 14 constitute a support (see...). Figure 3 This can be welded to the roof longitudinal beam M to improve the connection strength. When the roof longitudinal beam M is a beam or column of rectangular tube structure (see...), Figure 5 When the upper chord 1 and lower chord 2 are welded to the side of the rectangular tube by bevel welding or corner welding, they can be directly welded to the side of the rectangular tube by bevel welding or corner welding.

[0025] A prefabricated window mounting position 3 is provided in the middle of the upper chord 1 and the lower chord 2. The height of the prefabricated window mounting position 3 is 200~500mm and the length is 4~8m. One or two prefabricated aluminum alloy windows can be installed. The windows can be fixed or operable. The prefabricated window mounting position 3 is formed by the upper chord 1, the lower chord 2, and a pair of vertical bars 4 welded between the upper chord 1 and the lower chord 2. The two vertical bars 4 are also made of welded rectangular tubes or cold-formed thin-walled prefabricated rectangular tubes, and are symmetrically arranged along the central axis of the upper chord 1 and the lower chord 2.

[0026] To ensure that the deflection of the intermediate steel beam meets the requirements, a reinforcing rod 5 is also installed at the center of the two vertical rods 4, which is connected to the upper chord 1 and the lower chord 2. The front and rear width of the reinforcing rod 5 is reduced by 50~100mm compared with the upper chord 1 / lower chord 2, and it is located on the rear side of the finished window to meet the full length requirement of the flat and long window.

[0027] The aforementioned finished window mounting position 3 is further equipped with truss structures welded to the upper chord 1 and lower chord 2 on both sides. Specifically, the truss structure consists of vertical web members 6 and diagonal web members 7. The vertical web members 6 are evenly spaced between the upper chord 1 and lower chord 2, while the diagonal web members 7 are positioned between adjacent vertical web members 6. The aforementioned diagonal web members 7 are continuous diagonal web member structures (see...). Figure 1 ) or parallel diagonal web structure (see Figure 2 ).

[0028] As can be seen, the precast beam of this invention, composed of upper and lower chords and various web members, takes the form of an end truss with a central open window. Due to the fewer web members in the central window section, the self-weight of the component is effectively reduced. The truss-like form at the ends effectively strengthens the overall bending stiffness of the steel beam. The middle section uses reinforcing bars to connect the upper and lower chords, enhancing the overall integrity of the upper and lower chords without affecting the exterior window effect, effectively reducing the mid-span deflection of the steel beam, and facilitating the installation and fixing of the flat, elongated aluminum alloy precast window. It can be fabricated in the factory, effectively ensuring welding quality, high component precision, and excellent quality. After factory fabrication, it can be directly installed on-site, reducing on-site assembly procedures and saving construction time. This invention is lightweight, uses less steel, has a reasonable structure, and possesses many excellent features such as beam-window integration. It effectively solves the problem that traditional large-span stepped roof beams with windows cannot simultaneously consider load-bearing capacity, lighting, and aesthetics, making it highly valuable for industry promotion.

[0029] The construction method for the stepped precast roof beam with windows according to the present invention includes the following steps:

[0030] The first step is to lay out and cut the various components of the precast beam according to the design drawings;

[0031] The second step is to weld and process the various components of the precast beam according to the design drawings, and then debug and install the aluminum alloy windows to complete the factory prefabrication of the precast beam.

[0032] The third step is to transport the precast beams obtained in step two to the construction site, hoist and install them one by one. Each precast beam is located between adjacent step surfaces. The top surface of the upper chord 1 is flush with the upper step surface, and the bottom surface of the lower chord 2 is flush with the lower step surface. The two ends of the upper chord 1 and the lower chord 2 are welded to the roof longitudinal beam M.

[0033] The above construction methods are explained in detail below:

[0034] 1) Several rectangular steel tube components of different sizes are pre-produced in the factory according to design requirements, including top chord 1, bottom chord 2, vertical members 4, reinforcing members 5, vertical web members 6, and diagonal web members 7. Top chord 1 and bottom chord 2 are the same size, the two vertical members 4 have the same front-to-back width as top chord 1 and bottom chord 2, and the reinforcing member 5 has a front-to-back width 50-100mm smaller than the vertical members 4. All the above rectangular steel tube components are made of welded rectangular tubes or cold-formed thin-walled finished rectangular tubes. Simultaneously, finished aluminum alloy windows in the center are custom-made according to the dimensions in the design drawings; these can be fixed glass windows or operable windows.

[0035] 2) According to the design drawings, locate the center line of the rectangular tube, lay out the upper chord 1 and lower chord 2, and place the vertical bar 4, reinforcing bar 5, vertical web bar 6 and diagonal web bar 7 in the corresponding positions in conjunction with the upper chord 1, lower chord 2 and the design drawings. In large span steel beams, the upper chord 1 and lower chord 2 should be pre-cambered. The diagonal web bar 7 can be a continuous diagonal web bar or a parallel diagonal web bar. The ends of the diagonal web bar 7 at both ends should be connected to the lower chord 2.

[0036] 3) Lay out the intersection points of the center lines of the two vertical rods 4 with the center lines of the upper chord rod 1 and the lower chord rod 2. After laying out the intersection points on the line connecting the two intersection points, cut the pre-produced rectangular tube inclined web rod 7.

[0037] 4) Adjust the position of the reinforcing rod 5 backward according to the finished window installation position 3 to ensure that the window is not affected along its entire length at the position of the reinforcing rod 5, and that the inner edge of the reinforcing rod 5 is close to the inner edge of the upper chord 1 and the lower chord 2.

[0038] 5) The vertical rod 4, reinforcing rod 5, vertical web rod 6 and diagonal web rod 7 that have been laid out are connected to the upper chord rod 1 and lower chord rod 2 in the factory. Welding can be done by fillet weld or single-sided bevel weld.

[0039] 6) According to the support type and design requirements, cut 100~200mm vertically at both ends of the upper chord 1 and the lower chord 2 along the center line to form a vertical groove 12. The thickness of the vertical groove 12 is the thickness of the vertical connecting steel plate 13 on both sides +2mm, which facilitates the insertion of the vertical connecting plate 13 and the welding of the fillet weld.

[0040] 7) Insert the vertical connecting steel plate 13 into the vertical groove 12. After aligning it accurately according to the design drawings, weld the vertical connecting steel plate 13 with the upper chord 1 and the lower chord 2 using double-sided fillet welds.

[0041] 8) Weld the rectangular sealing plate 11 onto the vertical connecting steel plate 13, and at the same time weld the wall panels of the upper chord 1 and the lower chord 2 onto the rectangular sealing plate 11.

[0042] 9) After the overall components are processed and welded and pass quality inspection, install the pre-made aluminum alloy window frames and glass windows in the middle, complete the fabrication of the precast steel beams, and then transport them to the site by large transport vehicles for hoisting and installation.

[0043] 10) On-site, weld the vertical connecting steel plate 13 on the other side to the precast steel beam according to the design drawings. Various lifting equipment such as crawler cranes or tower cranes can be used on-site for component hoisting. After hoisting and positioning, weld the vertical connecting steel plate 13 on the overall steel beam to the steel beam on three sides using fillet welds or single-sided bevel welds. At the same time, weld stiffening ribs 14 to ensure the out-of-plane stability of the vertical connecting steel plate 13, and complete the installation of the precast beam and the roof longitudinal beam M.

[0044] It should be noted that the connection methods described in steps 6-8 and 10 above are for beams when the end supports are beams. In this invention, another connection method can be used when the end support is a rectangular tube beam, column, or H-shaped steel column flange. Figure 5 The connection method involves directly welding the upper chord 1 and lower chord 2 to the steel column using either corner welds or single-sided bevel welds.

[0045] In this invention, the vertical web members 6 and the diagonal web members 7 can also be welded H-beams or hot-rolled H-beams, while the upper chord 1 and the lower chord 2 are made of rectangular tubes. This avoids many difficulties caused by the small size of the upper and lower chords. Compared with the use of H-beams, it is lighter overall and has better component safety performance, while ensuring a reliable connection with the support.

[0046] It should be noted that in the description of this invention, terms such as "front," "rear," "left," "right," "vertical," "horizontal," "inner," and "outer" indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

Claims

1. A construction method for a stepped precast roof beam with windows, characterized in that: The precast beam includes a parallel upper chord and a lower chord, with a precast window mounting position in the middle of the upper chord and the precast window mounting position having a truss structure located between the upper chord and the lower chord on both sides of the precast window mounting position. The finished window installation position is enclosed by an upper chord, a lower chord, and a vertical bar set between the upper chord and the lower chord; The vertical members are arranged symmetrically in a pair along the central axis of the upper chord and the lower chord, and a reinforcing member connected to the upper chord and the lower chord is also provided between the vertical members; The reinforcing rod is arranged along the central axis of the upper and lower chords and is located on the rear side of the finished window; The construction method for the precast beams includes the following steps: The first step is to lay out and cut the various components of the precast beam according to the design drawings; The second step is to weld and process the various components of the precast beam according to the design drawings, and then debug and install the aluminum alloy windows to complete the factory prefabrication of the precast beam. The third step is to transport the precast beams obtained in step two to the construction site, hoist and install them one by one. Each precast beam is located between adjacent step surfaces. The top surface of the upper chord is flush with the upper step surface, and the bottom surface of the lower chord is flush with the lower step surface. The two ends of the upper and lower chords are welded to the roof longitudinal beams.

2. The method of installing a stepped, windowed roof precast beam according to claim 1, wherein: The truss structure consists of vertical web members and diagonal web members. The diagonal web members are arranged between adjacent vertical web members, and the diagonal web members are either continuous diagonal web member structures or parallel diagonal web member structures.

3. The method of installing a stepped, windowed roof precast beam according to claim 1, wherein: Both the upper chord and the lower chord are rectangular steel tube structures, and the ends of the upper chord and the lower chord are equipped with sealing plates.

4. The construction method of the stepped precast roof beam with windows according to claim 3, characterized in that: When the roof longitudinal beam is a hot-rolled H-beam or welded H-beam structure, a vertical groove is provided at the end of the upper chord and the lower chord. A vertical connecting steel plate is provided in the vertical groove. A stiffening rib located between the upper chord and the lower chord is welded to the left and right sides of the vertical connecting steel plate. The stiffening rib and the vertical connecting steel plate are welded to the web of the roof longitudinal beam.

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