Special-shaped steel structure of large-angle double-layer overhanging roof and construction method

Abstract

The present invention discloses a special-shaped steel structure for a large-angle double-layer cornice roof and a construction method. Among them, the special-shaped steel structure for the large-angle double-layer cornice roof includes an inner arc truss and an outer arc truss, and the outer arc truss is arranged on the outer side of the inner arc truss; both the inner arc truss and the outer arc truss are obtained by manual lofting and welding of multiple units according to the pre-assembly lofting drawings of the inner arc truss and the outer arc truss, and both the inner arc truss and the outer arc truss are supported by ground jigs during pre-assembly; lower chord beams are provided on both sides of the inner arc truss and the outer arc truss, and the lower chord beams are composed of multiple box girder units. The inner arc truss and the outer arc truss are also provided with column units, and the column units are composed of multiple columns and box girders. The construction method of the present invention is applicable to the above-mentioned special-shaped steel structure for the large-angle double-layer cornice roof. The present invention can replace the cornice roof structure of the concrete structure and be used on the large-angle double-layer cornice roof with a slope of more than 40°, realizing the construction of the large-angle double-layer cornice roof, and the construction is safer.

Description

Technical Field

[0001] The invention belongs to the technical field of steel structure engineering, and in particular relates to a large-angle double-layer flying eaves roof special-shaped steel structure, and also relates to a construction method of the large-angle double-layer flying eaves roof special-shaped steel structure. Background Art

[0002] When designing and constructing a large-angle double-layer eaves roof, if the design uses a reinforced concrete structure, the following problems will occur during the pouring of concrete because the roof slope exceeds 35 degrees (the slope has reached 40 degrees):

[0003] 1. If pumped concrete is used, the following situations will occur:

[0004] (1) The concrete placing machine cannot be placed on the sloped roof;

[0005] (2) The minimum slump of pumped concrete is 120-140. Due to the large roof slope, a large amount of concrete will slide and flow away, causing pollution to the lower structure and extremely poor molding effect.

[0006] (3) When pumping concrete, workers need to hug the discharge pipe to carry out the pouring operation. The vibration of the discharge port of the pump pipe cannot be avoided. However, due to the large slope of the roof, workers may not be able to operate during the concrete pouring, and safety accidents are very likely to occur.

[0007] 2. If artificial concrete pouring is used, the following problems will occur:

[0008] (1) When the roof slope is greater than 35 degrees, workers cannot stand on it normally, construction work is very difficult, and there are great safety hazards;

[0009] (2) The roof height is more than 10 meters, and the work efficiency is extremely low. At the same time, most of the roofs with a slope greater than 35 degrees are continuous large-area roofs. If artificial concrete pouring is used for construction, the construction period and cost will be huge; (most of the roofs with a slope less than 35 degrees are small-scale slopes, and the construction period and cost are relatively small. They can be barely implemented after overcoming considerable difficulties.)

[0010] (3) At the same time, the roof area of ​​a steeply sloped roof is relatively large. Manual pouring construction can only be carried out in layers of 10 to 15 cm before the initial setting of the concrete, resulting in a large number of construction joints, which are prone to deformation in the later stage, causing the roof tiles and other surface layers to crack or even fall off.

[0011] From the above analysis, it can be seen that concrete structures are unable to complete the construction of complex shapes of large-angle double-layer eaves roofs.

[0012] Since the concrete structure cannot complete the construction of the complex shape of the large-angle double-layer cornice roof, a special-shaped steel structure for the large-angle double-layer cornice roof is designed to solve the construction problem of the complex-shaped roof. On the other hand, the components of the special-shaped steel structure of the large-angle double-layer cornice roof are in a zigzag shape and vary greatly, making the installation and construction difficult. Therefore, a corresponding construction method is further designed to solve technical problems such as the orderly assembly and installation of on-site members. Summary of the Invention

[0013] The first technical problem to be solved by the present invention is to provide a special-shaped steel structure for a large-angle double-layer cornice roof.

[0014] The second technical problem to be solved by the present invention is to provide a construction method for the above-mentioned special-shaped steel structure of the large-angle double-layer cornice roof.

[0015] The present invention can replace the cornice roof structure of the concrete structure and be used on the large-angle double-layer cornice roof with a slope of more than 40°, realizing the construction of the large-angle double-layer cornice roof, making the construction safer and reducing the construction difficulty.

[0016] To solve the above first technical problem, the technical solution adopted by the present invention is as follows:

[0017] A special-shaped steel structure for a large-angle double-layer cornice roof, where the slope of the roof is more than 40°. It is characterized in that: it includes an inner arc truss and an outer arc truss, and the outer arc truss is arranged outside the inner arc truss; both the inner arc truss and the outer arc truss are obtained by manual lofting and welding of multiple units according to the pre-assembly lofting drawings of the inner arc truss and the outer arc truss, and both the inner arc truss and the outer arc truss are supported by ground jigs during pre-assembly; lower chord beams are provided on both sides of the inner arc truss and the outer arc truss, and the lower chord beam is composed of multiple box girder units. The inner arc truss and the outer arc truss are also provided with column units, and the column units are composed of multiple columns and box girders.

[0018] Optionally, the jig includes multiple support frames, and the support frames are distributed along the position of the lower chord beam. The height of each support frame is respectively adapted to the height of the lower chord beam, and the lower chord beam is supported on the support frames during pre-assembly.

[0019] To solve the above second technical problem, the technical solution adopted by the present invention is as follows:

[0020] A construction method for the above-mentioned special-shaped steel structure of the large-angle double-layer cornice roof, which is characterized by including the following steps:

[0021] S1: Perform manual lofting according to the lofting drawing of the inner arc truss;

[0022] S2: Layout the jig of the inner arc truss according to the lofting drawing;

[0023] S3: Hoist the box girder units of the inner arc truss onto the jig of the inner arc truss one by one. After adjusting to the corresponding positions according to the lofting drawing, make temporary fixation; finally, assemble the lower chord beam of the inner arc truss.

[0024] S4: Hoist the columns and box girders of the inner arc truss onto the jig of the inner arc truss respectively one by one. After adjusting to the corresponding positions according to the lofting drawing, make temporary fixation and assemble the column units of the inner arc truss; the column units of the inner arc truss are assembled with the lower chord beam in sequence to form the inner arc truss.

[0025] S5: Conduct manual lofting according to the lofting drawing of the outer arc truss.

[0026] S6: Set up the jig of the outer arc truss according to the lofting drawing.

[0027] S7: Hoist the box girder units of the outer arc truss onto the jig of the outer arc truss one by one. After adjusting to the corresponding positions according to the lofting drawing, make temporary fixation; finally, assemble the lower chord beam of the outer arc truss.

[0028] S8: Hoist the columns and box girders of the outer arc truss onto the jig of the outer arc truss respectively one by one. After adjusting to the corresponding positions according to the lofting drawing, make temporary fixation and assemble the column units of the outer arc truss; the column units of the outer arc truss are assembled with the lower chord beam in sequence to form the outer arc truss.

[0029] Optionally, each support point of the jigs in steps S2 and S6 is positioned and checked by a total station. The layout positions of the support points of the jig correspond to the node positions of the inner arc truss and the outer arc truss, and support points of the jig are provided near the ends of the inner arc truss and the outer arc truss; among them, the ground lines of the lofting drawing include total positioning control points, positioning axes, member contour lines, and projection of node center lines.

[0030] Optionally, when there are errors in the position of the jig, fine-tuning is carried out by padding temporary steel beams and wedges to ensure the accuracy of the inner arc truss and the outer arc truss during pre-assembly.

[0031] Optionally, the positioning of the box girder units in steps S3 and S7 is controlled by the X, Y, and Z coordinates of each main control point. The position of the box girder unit is adjusted by using a total station for positioning and hanging a plumb line to make the main control points at its ports coincide with the control points on the ground pattern. After the position adjustment is qualified, make temporary fixation of the box girder unit.

[0032] Optionally, the columns and box girders in steps S4 and S8 are adjusted by aligning with the ground lines of the lofting drawing, and the parallelism with the ground lines is corrected. After the position adjustment is qualified, make temporary fixation.

[0033] Optionally, the jigs in steps S2 and S6 are welded by I-beams or channel steels.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The large-angle double-layer cornice roof of the present invention includes an inner arc truss and an outer arc truss. Both the inner arc truss and the outer arc truss are steel structures, which are used to replace the concrete structure, enabling the realization of the large-angle double-layer cornice roof. It can be pre-assembled by being supported by a ground falsework and then hoisted onto the roof, making the construction safer and reducing the construction difficulty.

[0036] Both the inner arc truss and the outer arc truss of the present invention are obtained by manually lofting and welding multiple units according to the pre-assembly lofting drawings of the inner arc truss and the outer arc truss. The splicing method of supporting the units by the falsework is used to reduce the complexity of constructing the large-angle double-layer cornice roof and achieve orderly assembly.

[0037] 2. The inner arc truss of the present invention is preferentially installed, which can ensure the overall stability and sequentially connect the lower chord beam and the column unit according to the structural requirements.

[0038] 3. The present invention uses a total station to verify each control point. The ground line of the lofting drawing includes total positioning control points, positioning axes, component contour lines, and the projection of node center lines, etc., which can ensure the overall accuracy.

[0039] The errors existing in the falsework can be finely adjusted by using temporary steel beams and wedges, etc. in the subsequent process to ensure the accuracy of the inner arc truss and the outer arc truss during pre-assembly. The overall installation method can adapt to the accuracy and effect of the assembly of the special-shaped steel structure of the large-angle double-layer cornice roof.

[0040] The present invention can not only ensure the overall stability but also has high accuracy.

[0041] 4. The present invention can achieve important indicators: the large overhanging part reaches more than 4.0 m; the double-layer cornice slope reaches more than 40 degrees, which cannot be achieved by the roofs of concrete structures and existing steel structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is one of the schematic diagrams of the large-angle roof surface;

[0043] Figure 2 is the second schematic diagram of the large-angle roof surface;

[0044] Figure 3 is the third schematic diagram of the large-angle roof surface;

[0045] Figure 4 is the schematic diagram when the special-shaped steel structure of the large-angle double-layer cornice roof is arranged on a 40° roof surface;

[0046] Figure 5 is the schematic diagram when the inner arc truss of the present invention is pre-assembled through the falsework.

[0047] Meanings of the reference numerals in the figures:

[0048] 1 - Inner arc truss; 2 - Lower chord beam; 3 - Box girder; 4 - Falsework; 5 - Support frame; 6 - Box girder unit. Detailed implementation manners

[0049] The present invention will be further described below in conjunction with embodiments.

[0050] In the description of the present invention, it should be understood that for the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0051] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, exceeding, etc. are understood as not including the present number, and above, below, within, etc. are understood as including the present number. If the first and second are described only for the purpose of distinguishing technical features, they should not be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or the sequence relationship of the indicated technical features.

[0052] In the description of the present invention, unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0053] Embodiment:

[0054] The special-shaped steel structure of the large-angle double-layer cornice roof in this embodiment includes an inner arc truss and an outer arc truss. The outer arc truss is arranged outside the inner arc truss to form the double-layer cornice of the special-shaped steel structure of the roof.

[0055] The special-shaped steel structure of the large-angle double-layer cornice roof in this embodiment can be applied to large-angle roof surfaces, such as Figures 1 to 3 All shown are large-angle roof surfaces.

[0056] Among them, both the inner-arc truss and the outer-arc truss are obtained by manual lofting and welding of multiple units according to the pre-assembly lofting drawings of the inner-arc truss and the outer-arc truss. During pre-assembly, both the inner-arc truss and the outer-arc truss are supported by ground jigs. Lower chord beams 2 are provided on both sides of the inner-arc truss and the outer-arc truss. The lower chord beam 2 is composed of multiple box girder units 6, that is, the lower chord beam 2 is assembled in sequence by multiple box girder units 6. The inner-arc truss and the outer-arc truss are also provided with column units, and the column units are composed of multiple columns and box girder 3. The box girder 3 is a small box girder. The two sides of the inner-arc truss and the outer-arc truss are connected by the side-by-side column units to form an integral body, and the columns are used to support on the steel frame of the roof.

[0057] As Figure 5 shown in the schematic diagram, the jig 4 includes multiple support frames 5. The upper end of the support frame 5 is provided with a support point for supporting the lower chord beam 2. The support frames 5 are distributed along the position of the lower chord beam 2. The height of each support frame 5 is respectively adapted to the height of the lower chord beam 2. During pre-assembly, the lower chord beam 2 is supported on the support frames 5.

[0058] For a specific structure of the steel structure, in addition to the steel frames of the inner-arc truss and the outer-arc truss that form its double-layer cornice, there are also secondary beams, struts and tie rods and other steel structures, and it also includes main steel frame beams, secondary steel frame beams, steel columns, light steel main keels and secondary keels, steel purlins, horizontal supports, etc.; the cross-section of the main steel frame beam adopts section steel H400×250×8×16, H400×300×10×18, H400×200×8×13, the cross-section of the secondary steel frame beam adopts section steel H400×200×8×13. Longitudinal secondary beams and steel supports are arranged between the transverse main and secondary steel frame beams. The cross-section of the secondary beam is H-shaped steel HN450×200, and the cross-section of the steel tie rod is round steel Φ30. As Figure 4 shown is the structural schematic diagram when the special-shaped steel structure of the large-angle double-layer cornice roof is set on the roof.

[0059] The steel structure material adopts Q235B, and the cross-section form of the component is welded H-shaped steel or hot-rolled H-shaped steel, and it should meet the requirements of the end face shrinkage rate index of Z15 level and the sulfur content not exceeding 0.01%. On-site welding mainly uses manual welding and CO2 gas semi-automatic welding. All groove butt welds are of the first grade, and the rest of the welds are of the second grade. The maximum allowable error of the structural shape: (1) The node offset is 5 mm; (2) The beam top elevation is 5 mm; (3) The beam length is L / 2000 or 15 mm, etc. There are many nodes and various forms. Among them, the main and secondary steel frame beams, steel columns and supports mainly adopt the rigid connection form and the pin shaft bolt connection form.

[0060] The main steel structure of the roof is composed of a broken-line-shaped steel beam steel frame and corresponding secondary steel frames, and is successively supported on steel columns. The main steel frame adopts an H-shaped cross-section, the maximum thickness of the steel plate is 22 mm, the length is 12 - 15 m, the maximum single beam weight is 2.1 tons, and the material is Q235B.

[0061] This embodiment also discloses a construction method for the special-shaped steel structure of the above-mentioned angular double-layer cornice roof, which includes the following steps:

[0062] S1: Perform manual lofting according to the lofting drawing of the inner arc truss 1;

[0063] S2: Layout the jig for the inner arc truss 1 according to the lofting drawing;

[0064] S3: Hoist the box girder units 6 of the inner arc truss 1 onto the jig 4 of the inner arc truss in sequence. After adjusting to the corresponding positions according to the lofting drawing, perform temporary fixation; finally, assemble the lower chord beam 2 of the inner arc truss; The box girder units 6 need to be qualified before assembly;

[0065] S4: Hoist the columns and box girders 3 of the inner arc truss 1 onto the jig 4 of the inner arc truss in sequence. After adjusting to the corresponding positions according to the lofting drawing, perform temporary fixation, and assemble into column units; The column units are assembled with the lower chord beam 2 in sequence to form the inner arc truss 1;

[0066] As Figure 5 shown, through the above steps S1 - S4, the installation of the inner arc truss 1 will be preferentially completed, and the inner arc truss will be hoisted onto the roof.

[0067] S5: Perform manual lofting according to the lofting drawing of the outer arc truss;

[0068] S6: Layout the jig for the outer arc truss according to the lofting drawing;

[0069] S7: Hoist the box girder units of the outer arc truss onto the jig of the outer arc truss in sequence. After adjusting to the corresponding positions according to the lofting drawing, perform temporary fixation; finally, assemble the lower chord beam of the outer arc truss;

[0070] S8: Hoist the columns and box girders of the outer arc truss onto the jig of the outer arc truss in sequence. After adjusting to the corresponding positions according to the lofting drawing, perform temporary fixation, and assemble into column units of the outer arc truss; The column units of the outer arc truss are assembled with the lower chord beam in sequence to form the outer arc truss.

[0071] Through the above steps S5 - S8, the installation of the outer arc truss will be completed, and the outer arc truss will be hoisted onto the roof surface.

[0072] Among them, each support point of the jigs in steps S2 and S6 is positioned and verified by a total station. The layout positions of the support points of the jig correspond to the node positions of the inner arc truss and the outer arc truss, and support points of the jig are provided near the ends of the inner arc truss and the outer arc truss. Among them, the ground sample line of the lofting drawing should include total positioning control points, positioning axes, component contour lines, and projection of node center lines, etc.

[0073] When there are errors in the position of the jig 4, fine-tuning can be carried out by inserting temporary steel beams and wedges to ensure the accuracy of the inner arc truss and the outer arc truss during pre-assembly.

[0074] The positioning of the box girder unit 6 in steps S3 and S7 is controlled by the X, Y, and Z coordinates of each main control point. The total station is used for positioning and a plumb line is suspended to adjust the position of the box girder unit so that the main control points at its ports coincide with the control points on the ground pattern. After the position adjustment is qualified, the box girder unit is temporarily fixed.

[0075] The columns and the box girder 3 in steps S4 and S8 are adjusted by aligning with the ground pattern lines of the lofting drawing, and the parallelism with the ground pattern lines is corrected. After the position adjustment is qualified, they are temporarily fixed.

[0076] The jig in steps S2 and S6 is welded by I-beams or channel steels. As Figure 5 shown, the support frame 5 of the jig is in the shape of a triangular frame, and the lower ends are connected together by steel frames to form an integral body.

[0077] By designing the sizes and corner surface positions of the components of the cornice, and carrying out pre-assembly, the data of each component is transmitted to the processing factory for cutting and manufacturing, and the components are assembled and installed in sequence at the construction site. The total station is used for measuring and positioning to control the accuracy and elevation, so as to ensure the installation quality.

[0078] The double-layer cornice formed by the large-angle double-layer cornice roof special-shaped steel structure in this embodiment can reach the following indicators (which cannot be achieved by the concrete structure and the existing steel structure roofs):

[0079] 1. The large cantilever part reaches 4.0 m;

[0080] 2. The slope of the double-layer cornice reaches 40 degrees, and the arc line is beautiful;

[0081] 3. The axis error is controlled within 2 mm.

[0082] The above embodiments of the present invention do not limit the protection scope of the present invention. The implementation manners of the present invention are not limited to this. All kinds of modifications, substitutions or changes made to the above structure of the present invention according to the above content of the present invention, in accordance with the common general technical knowledge and customary means in the art, without departing from the above basic technical idea of the present invention, shall fall within the protection scope of the present invention.

Claims

1. A construction method for a special-shaped steel structure of a large-angle double-layer flying eave roof, characterized in that, The slope of the roof is more than 40°. The special-shaped steel structure of the large-angle double-layer flying eave roof includes an inner arc truss and an outer arc truss, and the outer arc truss is arranged outside the inner arc truss; both the inner arc truss and the outer arc truss are obtained by manually lofting and welding multiple units according to the pre-assembly lofting drawings of the inner arc truss and the outer arc truss, and both the inner arc truss and the outer arc truss are supported by ground jigs during pre-assembly; lower chord beams are provided on both sides of the inner arc truss and the outer arc truss, the lower chord beams are composed of multiple box beam units, and column units are also provided on the inner arc truss and the outer arc truss, and the column units are composed of multiple columns and box beams; The construction method includes the following steps: S1: Manually loft according to the lofting drawing of the inner arc truss; S2: Layout the jig of the inner arc truss according to the lofting drawing; S3: Hoist the box beam units of the inner arc truss onto the jig of the inner arc truss in sequence. After adjusting to the corresponding positions according to the lofting drawing, perform temporary fixation; finally assemble the lower chord beam of the inner arc truss; S4: Hoist the columns and box beams of the inner arc truss onto the jig of the inner arc truss in sequence. After adjusting to the corresponding positions according to the lofting drawing, perform temporary fixation, and assemble the column units of the inner arc truss; the column units of the inner arc truss are sequentially assembled with the lower chord beam to form the inner arc truss; S5: Manually loft according to the lofting drawing of the outer arc truss; S6: Layout the jig of the outer arc truss according to the lofting drawing; S7: Hoist the box beam units of the outer arc truss onto the jig of the outer arc truss in sequence. After adjusting to the corresponding positions according to the lofting drawing, perform temporary fixation; finally assemble the lower chord beam of the outer arc truss; S8: Hoist the columns and box beams of the outer arc truss onto the jig of the outer arc truss in sequence. After adjusting to the corresponding positions according to the lofting drawing, perform temporary fixation, and assemble the column units of the outer arc truss; the column units of the outer arc truss are sequentially assembled with the lower chord beam to form the outer arc truss.

2. The construction method according to claim 1, characterized in that: All support points of the jigs in steps S2 and S6 are positioned and checked by a total station. The layout positions of the support points of the jig correspond to the node positions of the inner arc truss and the outer arc truss, and support points of the jig are provided near the ends of the inner arc truss and the outer arc truss; among them, the ground lines of the lofting drawing include total positioning control points, positioning axes, component contour lines, and node center line projections.

3. The construction method according to claim 2, characterized in that: When there is an error in the position of the jig, fine adjustment is carried out by padding temporary steel beams and wedges to ensure the accuracy of the inner arc truss and the outer arc truss during pre-assembly.

4. The construction method according to claim 1, characterized in that: The positioning of the box beam units in steps S3 and S7 is controlled by the X, Y, and Z coordinates of each main control point. The position of the box beam unit is adjusted by using a total station for positioning and hanging a plumb line to make the main control points at its ports coincide with the control points on the ground line. After the position adjustment is qualified, temporary fixation is carried out on the box beam unit.

5. The construction method according to claim 1, characterized in that: The columns and box beams in steps S4 and S8 are adjusted by aligning with the ground lines of the lofting drawing, and the parallelism with the ground lines is corrected. After the position adjustment is qualified, temporary fixation is carried out.

6. The construction method according to claim 1, characterized in that: The jig for steps S2 and S6 is welded by using I-beams or channel steels.

7. The construction method according to claim 1, characterized in that: The jig includes a plurality of support frames which are distributed along the position of the lower chord beam. The height of each support frame is respectively adapted to the height of the lower chord beam. When pre-assembling, the lower chord beam is supported on the support frames.

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