Construction method of super high-rise large-span cantilever steel structure

Abstract

The invention discloses a construction method for a super high-rise large-span cantilever steel structure. The construction method comprises the steps that S1, a construction flow section is divided; s2a, steel column and steel beam construction closest to the cantilever area; s2b, upper-layer floor formwork and steel bar binding construction is conducted synchronously; s3a, construction of the cantilever steel structure; s3b, upper floor slab concrete pouring is conducted synchronously; and S4, pouring floor slabs in the cantilever area. According to the construction method, the construction process is reasonably planned, on the premise that other construction links are not affected, mounting construction of the cantilever steel structure is started in advance, the situation that personnel are idle or equipment idles due to the fact that the construction progress of the cantilever steel structure is slow is avoided, the construction efficiency is improved, and the construction cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a construction method for a super-high-rise large-span cantilevered steel structure. Background Art

[0002] In recent years, the rapid progress of architectural technology has not only promoted the innovation of structural design in terms of functionality, but also made it an important carrier for achieving the pursuit of architectural aesthetics. Large-span cantilever truss structures are increasingly favored for their various forms and visual impact, and are widely used in various modern buildings that pursue unique shapes and spatial experiences. However, due to the large span and nonlinear characteristics of such structures, the safety factors involved in the construction process are more complicated, and the progress control and quality requirements of the project have reached a higher level.

[0003] The prerequisite for the construction of large-span cantilever steel structures is that the strength of the main structure meets the construction requirements. In the construction projects involved in the present invention, the original construction plan was to start construction after the construction progress of the main structure exceeded the cantilever layer by more than two to three floors. However, the following problems were encountered in the specific personnel arrangements and equipment scheduling: the cantilever steel structure construction node was too late, resulting in relatively slow construction, which caused idle labor or idling equipment, and invisibly increased the construction cost.

[0004] Therefore, how to create a new construction method for super-high-rise large-span cantilevered steel structures so that the cantilevered steel structures can be put into construction ahead of schedule without affecting other construction processes is one of the important current research and development topics. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a construction method for a super-high-rise large-span cantilevered steel structure, so that it can enter the construction site in advance without affecting other construction processes, avoid idle labor or idling equipment, improve construction efficiency, reduce construction costs, and thus overcome the shortcomings of existing technologies.

[0006] In order to solve the above technical problems, the present invention provides a construction method for a super-high-rise large-span cantilever steel structure, wherein the layer where the lower chord of the cantilever steel structure is located is the current layer, and the layer where the upper chord is located is the upper layer, and the specific construction steps include: S1. Construction flow section division; The current layer and the upper layer are divided into construction flow sections as a whole. The area where the cantilever steel structure is located is divided into the cantilever area, the area corresponding to the cantilever area in the longitudinal direction and the area adjacent to the cantilever area in the transverse direction by at least one span are divided into the cantilever adjacent area, and the area other than the cantilever area and the cantilever adjacent area is divided into the conventional construction area; S2a, construction of steel columns and beams closest to the cantilever area; In the cantilever adjacent area, the four steel columns closest to the cantilever area in the longitudinal and transverse directions and the steel beams between the columns are installed and welded first to form a stable frame structure; S2b, carry out the upper floor slab formwork and steel bar binding construction simultaneously; S3a, cantilever steel structure construction; The construction of cantilever steel structure starts when the following construction conditions are met; Condition 1: The pouring of the floor slab is completed; Condition 2: The welding of the four steel columns closest to the cantilever area and the steel beams between the columns is completed; Condition 3: Pour concrete into the four steel columns closest to the cantilever area to the level below the current level; The construction sequence of the cantilever steel structure is: install and weld in the order of lower chord, diagonal rod, vertical rod, upper chord, diagonal web rod, inner cross beam, outer lower chord rod and edge beam; S3b, pouring concrete for the upper floor slab simultaneously; S4, pouring of floor slab in cantilevered area; After the cantilever steel structure construction is completed and the upper floor slab is poured, the cantilever area floor slab will be poured.

[0007] As an improvement of the present invention, the steel beam in step S2 is a profiled steel beam.

[0008] Furthermore, the step S2a specifically includes: S2a1, steel column lifting; S2a2, after the steel column is in place, use the jack for correction; S2a3, temporary fixation after steel column correction; S2a4, lifting of steel beams; S2a5, align the steel beams and temporarily fix them; S2a6, welding of steel columns and steel beams.

[0009] The step S2b specifically includes: S2b1, upper floor slab formwork construction; Construction begins after step S2a3 is completed and is carried out simultaneously with the subsequent steps of S2a3; S2b2, beam and slab reinforcement binding of upper floor; After step S2a5 is completed, construction begins and is performed simultaneously with the subsequent steps of S2a5.

[0010] Furthermore, the step S3a specifically includes: S3a1, installation of lower chord and diagonal rod; The lower chord and the diagonal rod are assembled on the ground, and the joints are fixed with temporary connecting plates and bolts. After assembly, they are hoisted as a whole, and welded immediately after hoisting in place and calibration. After the non-destructive test is passed, the subsequent steps are carried out; S3a2, pole installation; S3a3, string installation; The end of the upper chord is provided with an extension section, which is used as an installation point for the fall chain and the wire rope in subsequent steps; S3a4, diagonal brace installation; S3a5, inner crossbeam installation; S3a6, installation of outer lower chord and edge beam; Install the outer lower chord first, then install the edge beam; Before installation, determine the diagonal tension value based on construction simulation and select corresponding specifications of fall chains and wire ropes; During installation, fix the upper end of the fall chain to the extension section of the upper chord, adjust and correct it through the fall chain, connect the wire rope after correction, and remove the fall chain and wire rope after welding.

[0011] After adopting such a design, the present invention has at least the following advantages: 1. By reasonably dividing the construction flow sections, the cantilever layer is divided into cantilever area, cantilever adjacent area and conventional construction area. Each construction process is carried out in an orderly manner within the partition to ensure that the early construction of the cantilever steel structure does not affect the progress of other processes; 2. Improve the inter-column beams between the four steel columns closest to the cantilever area from traditional concrete beams to steel beams. Prioritize the installation, correction and welding of the four steel columns and inter-column steel beams to quickly and efficiently form a stable frame structure as the installation basis of the cantilever steel structure, so that the cantilever steel structure can be put into construction ahead of schedule; 3. The upper floor formwork construction and steel bar binding construction can be carried out simultaneously with the installation of the four steel columns and the steel beams between the columns closest to the cantilever area. The upper floor slab can be poured simultaneously with the installation of the cantilever steel structure, avoiding idle labor or idling equipment due to the slow progress of the cantilever steel structure construction, effectively improving construction efficiency, shortening construction period and reducing construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0013] Figure 1 The invention discloses a construction process diagram of a super-high-rise large-span cantilever steel structure construction method.

[0014] Figure 2 It is a schematic diagram of the division of construction flow sections in step S1.

[0015] Figure 3 It is a schematic diagram of the positions of the steel columns and beams closest to the cantilever area in step S2a.

[0016] Figure 4 It is a schematic diagram of the installation status of the lower chord and the diagonal rod in step S3a1.

[0017] Figure 5 It is a schematic diagram of the installation status of the vertical pole in step S3a2.

[0018] Figure 6 It is a schematic diagram of the installation state of winding in step S3a3.

[0019] Figure 7 It is a schematic diagram of the installation state of the diagonal brace in step S3a4.

[0020] Figure 8 It is a schematic diagram of the installation state of the inner crossbeam in step S3a5.

[0021] Fig. 9 It is a schematic diagram of the installation status of the outer lower chord and the edge beam in step S3a6.

[0022] Fig.10 It is a schematic diagram of the state after the upper floor slab is poured in step S3b.

[0023] Fig.11 It is a schematic diagram of the state after the cantilever area floor slab is poured in step S4.

[0024] Explanation of the reference numerals in the figures: 1. Cantilever steel structure; 2. Steel columns and beams closest to the cantilever area; 3. Floor slab of the current floor; 4. Lower chord; 5. Diagonal bars; 6. Vertical bars; 7. Upper chord; 8. Diagonal web members; 9. Inner cross beam; 10. Outer lower chord and edge beam; 11. Upper floor slab; 12. Floor slab in cantilever area; B1. Conventional construction area; B2. Cantilever adjacent area; B3. Cantilever area. DETAILED DESCRIPTION

[0025] See also Figure 1 The present invention provides a super-high-rise large-span cantilever steel structure construction method, which enables the cantilever steel structure 1 to start construction in advance and be constructed synchronously with other processes without affecting each other.

[0026] In this embodiment, the cantilever steel structure 1 includes a lower chord 4, an oblique rod 5, a vertical rod 6, an upper chord 7, an oblique web member 8, an inner cross beam 9, an outer lower chord member and an edge beam 10, wherein the lower chord 4, the inner cross beam 9, the outer lower chord member and the edge beam 10 are all located at the 14th floor, the upper chord 7 is located at the 15th floor, and the oblique rod 5, the vertical rod 6 and the oblique web member 8 are located between the 14th and 15th floors. For ease of description, the layer where the lower chord is located is defined as the current layer, and the layer where the upper chord is located is defined as the upper layer, that is, the 14th floor is the current layer, and the 15th floor is the upper layer.

[0027] Step S1: Divide the construction flow sections.

[0028] See also Figure 2 , the current layer and the upper layer are divided into construction flow sections as a whole, the area where the cantilever steel structure 1 is located is divided into the cantilever area B3, the area corresponding to the cantilever area B3 in the longitudinal direction and the area adjacent to the cantilever area in the transverse direction by at least one span is divided into the cantilever adjacent area B2, and the area other than the cantilever adjacent area B2 and the cantilever adjacent area B3 is divided into the conventional construction area B1. The significance of reasonable division of flow sections is to clarify the operation areas and nodes for the subsequent synchronous construction process and avoid mutual influence in synchronous construction or interlaced construction.

[0029] Step S2a: Construction of steel columns and beams closest to the cantilever area.

[0030] See also Figure 3 In the cantilever adjacent area B2, the steel column and steel beam 2 closest to the cantilever area are installed and welded first. In this embodiment, the cantilever area B1 is located at a corner of the 14th floor. There are four steel columns closest to the cantilever area B1, all of which are round tube steel columns with a maximum cross-section of D1200×30mm and a material of Q390B. There are two inter-column beams between the four steel columns closest to the cantilever area B1, which are steel beams with a maximum cross-section of H500×400×20×40mm and a material of Q355B.

[0031] After the installation and welding are completed first, a stable frame structure can be formed, which serves as the installation basis of the cantilever steel structure 1 in the subsequent steps. The specific construction steps of step S2a are as follows.

[0032] Step S2a1: lifting the steel column.

[0033] Before lifting the steel column, first clear the debris and loose rust from the top surface of the lower steel column and the bottom surface of the current steel column, tie the ladder and fall arrester to the top of the column, and hang the slip rope.

[0034] Before lifting, the steel column should be placed horizontally on the wooden pads, and there should be no dragging on the ground. It should be at a certain height when rotating. When lifting, the three actions of hooking, rotating and moving are performed alternately and slowly, and it falls slowly when in place.

[0035] During the lifting process, two guy ropes are used to keep the steel column stable.

[0036] Step S2a2: After the steel column is in place, it is calibrated using a jack.

[0037] The steel column is lifted steadily, moved at a uniform speed, and lowered slowly. The direction of the corbel is adjusted according to the construction drawings. After lifting into place, the center axis, elevation and verticality are corrected.

[0038] The center axis is corrected by using jacks and clips. The positioning axis of each steel column should be drawn directly from the reference line and must not be drawn from the axis of the lower column to avoid excessive cumulative errors.

[0039] The elevation and verticality correction are adjusted by using a jack or by driving steel wedges between columns, and the adjustment process is monitored throughout by a total station.

[0040] In this embodiment, the specific method of steel column correction is to weld clamping plates on the front and rear sides of the steel column, and weld L-shaped steel on the left and right sides, which serve as the supporting points of the jack respectively. The clamping plates are horizontally welded near the top of the lower section steel column and the bottom of the current section steel column, and the jack is placed between the two clamping plates for lifting to adjust the inclination of the steel column. The L-shaped steel is welded near the top of the lower section steel column, and the jack is placed between the L-shaped steel and the current section steel column for lifting to adjust the horizontal displacement of the steel column.

[0041] Step S2a3: Temporarily fix the steel column after correction.

[0042] After the steel column is calibrated, insert the double plywood smoothly into the connecting ear plate of the lower column and tighten the bolts for temporary fixation.

[0043] Step S2a4: lifting the steel beam.

[0044] The steel beam is a section steel beam. Before lifting, a safety rope pole is set and a safety rope is hung. Tool bags are hung at both ends of the steel beam to place tools such as bolts, crowbars, wrenches, etc., and a slip rope is set.

[0045] The steel beam is hoisted with two lifting points, which are located on both sides of the center of the steel beam. Two slip ropes are hung at both ends of the steel beam. During hoisting, two workers hold the two slip ropes respectively. The lifting speed must be slow at the beginning, and personnel must not stand directly under the steel beam.

[0046] Step S2a6: Align and temporarily fix the steel beam.

[0047] When the steel beam is hoisted above the position, the steel beam is put into place. During the process of positioning, the falling speed of the steel beam is strictly controlled. Two workers stand on the brackets of the steel columns at both ends, ready to install. When the steel beam is close to the position, the workers hold the steel beam with their hands and slowly drag it to the position.

[0048] After the steel beam is in place, it is connected and fixed to the steel column by bolts. For longer steel beams, the holes at both ends of the steel beam should be tightened and aligned with punches first, and then ordinary bolts should be inserted and tightened. The number of ordinary installation bolts shall not be less than 30% of the total number of bolts at the node, and shall not be less than two. If the hole position deviation occurs during installation, the hole can only be expanded by machine reaming, and gas cutting shall not be used to expand the hole.

[0049] Step S2a7: welding of steel columns and steel beams.

[0050] After the temporary fixation of the steel beam is completed, the steel column and the steel beam are adjusted as a whole again, and welding is performed after they meet the design requirements. The welding of the steel column is performed symmetrically by two workers, and the ear plate is cut off after 2 / 3 of the welding is completed. The parent material must not be burned when cutting.

[0051] Step S2b: Simultaneously carry out the upper floor slab formwork and reinforcement binding construction.

[0052] Step S2b specifically includes S2b1 upper floor slab formwork construction and S2b2 upper floor slab beam and slab reinforcement binding.

[0053] Step S2b1 is the formwork construction of the upper floor slab. After the steel columns are temporarily fixed (step S2a3), the formwork construction can begin. Step S2b2 is the steel bar binding of the beam slab of the upper floor slab. After the steel beams are temporarily fixed (step S2a5), the steel bar binding construction can begin.

[0054] It should be noted that the above steps S2b1 and S2b2 only make requirements for the starting nodes for synchronous construction. Whether to adopt synchronous construction needs to be adjusted according to the construction progress, construction arrangement and number of personnel at the construction site.

[0055] In addition, the above step S2a is only a construction step for the four steel columns and two steel beams closest to the cantilever area B3 in the cantilever adjacent area B2. After completion, the remaining steel columns of this layer need to be installed and welded. The construction method is similar to step S2a. The only difference is that the inter-column beams of the remaining steel columns are all concrete beams, and the concrete beams are cast simultaneously with the upper floor slabs. Therefore, the installation and welding of the remaining steel columns only need to execute steps S2a1, S2a2, S2a3 and S2a6.

[0056] Step S3a: cantilever steel structure construction.

[0057] Before the construction of cantilever steel structure 1, the following construction conditions must be met: Condition 1: The pouring of the floor slab is completed.

[0058] Condition 2: The welding of the four steel columns closest to the cantilever area and the steel beams between the columns is completed.

[0059] Condition 3: Pour concrete into the four steel columns closest to the cantilever area to the floor below the current floor, that is, pour concrete into the columns to the 13th floor.

[0060] The construction sequence of the cantilever steel structure 1 is: install and weld in the order of lower chord, diagonal rod, vertical rod, upper chord, diagonal web member, inner cross beam, outer lower chord and edge beam, as shown below.

[0061] Step S3a1: Install the lower chord and diagonal rod.

[0062] See also Figure 4 The lower chord 4 and diagonal rod 5 of the cantilever steel structure 1 are assembled on the ground, and temporary connecting plates and bolts are used for fixing. After assembly, the whole structure is hoisted, and after hoisting in place and correction, it is welded immediately, and the subsequent steps are carried out after the non-destructive inspection is passed.

[0063] In this embodiment, the lower chord 4 is respectively located at the 1-3 axis (vertical direction in the figure) and the 1-D axis (horizontal direction in the figure) of the 14th floor. First, the lower chord 4 and the diagonal rod 5 of the 1-3 axis are hoisted as a whole. After hoisting, the lower chord 4 and the corbel reserved for the steel column are temporarily fixed with bolts, and then the lower chord 4 and the diagonal rod 5 of the 1-D axis are hoisted in place in the same way. After the lower chords 4 on both sides are calibrated, they are immediately welded. After welding is completed, non-destructive testing of the welding points is performed.

[0064] Step S3a2: Pole installation.

[0065] See also Figure 5 , hoist the vertical pole 6, calibrate it after it is in place, and weld it immediately after calibration.

[0066] Step S3a3: Winding and installation.

[0067] See also Figure 6 , install the upper chords 7 of the 1-3 axis and the 1-D axis respectively, and extend an extension section from the ends of the upper chords 7 on both sides, which are used as installation points for the fall chains and wire ropes in subsequent steps.

[0068] Step S3a4: Installation of diagonal braces.

[0069] See also Figure 7 , and install and weld the remaining diagonal web members 8 in the cantilever steel structure 1 one by one.

[0070] Step S3a5: Install the inner crossbeam.

[0071] See also Figure 8 The inner cross beam 9 is located between the lower chord 4 and the floor slab of this layer, and is installed and welded after being hoisted into place one by one.

[0072] Step S3a6: installing the outer lower chord and edge beam.

[0073] See also Fig. 9 The outer lower chord rod and the edge beam 10 are located on the outer side of the lower chord 4. During installation, the outer lower chord rods are installed one by one, and then the edge beam is installed.

[0074] Before installation, determine the diagonal tension value based on construction simulation and configure fall chains and wire ropes of corresponding specifications.

[0075] During installation, fix the upper end of the fall chain to the extension section of the upper chord 7, adjust and correct it through the fall chain, connect the wire rope after correction, and remove the fall chain and wire rope after welding.

[0076] In this embodiment, the lower chord of the outer side of the 1-D axis needs to be fixed with the extension section of the upper chord 7 of the 1-D axis. This is the point where the diagonal tension value is the largest, and the diagonal tension value is 51.4KN. The fall chain adopts a 10t manual fall chain, the wire rope adopts a 6×37FS, a fiber core pressed joint, a nominal tensile strength of 1770MPa, a wire rope diameter of 12mm, and a minimum breaking tension of 84.1KN, which meets the construction requirements. The maximum tension value of the remaining outer lower chord and edge beam is 11.1KN, the fall chain adopts a 5t manual fall chain, the wire rope adopts a 6×37FS, a fiber core pressed joint, a nominal tensile strength of 1770MPa, a wire rope diameter of 8mm, and a minimum breaking tension of 37.4KN, which meets the construction requirements.

[0077] Step S3b: Concrete pouring of the upper floor slab is performed simultaneously.

[0078] See also Fig.10 , the construction condition of step S3b is that step S2b is completed in both the cantilever area B2 and the conventional construction area B1. It should be noted that, except for the inter-column beams of the four steel columns closest to the cantilever area B3, which are made of section steel beams, the remaining inter-column beams are all concrete beams. Regardless of whether it is a section steel beam or a concrete beam, the bottom elevation of the beam is uniform and flush with the floor elevation, that is, the upper floor slab 11 wraps the beam inside. In step S2b, the floor slab reinforcement is tied to the steel beam at the section steel beam, and at the concrete beam, the beam formwork and the floor slab formwork are integrated together and built. After step S2b is completed, the construction of step S3b can be carried out, and step S3b is carried out simultaneously with step S3a.

[0079] Step S4: pouring the cantilevered area floor slab.

[0080] After the construction of the cantilever steel structure 1 is completed and the casting of the upper floor slab 11 is completed, that is, after both steps S3a and S3b are completed, the casting of the cantilever area floor slab 12 is carried out.

[0081] The construction method provided by the present invention starts the installation construction of the cantilever steel structure in advance without affecting other construction links by reasonably planning the construction process, thereby avoiding idle personnel or idling equipment due to slow progress of the cantilever steel structure construction, improving construction efficiency and reducing construction costs.

[0082] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Those skilled in the art may make some simple modifications, equivalent changes or modifications using the technical contents disclosed above, which all fall within the protection scope of the present invention.

Claims

1. A method for constructing a super high-rise large-span cantilever steel structure, characterized in that: The layer where the lower chord of the cantilever steel structure is located is the main layer, and the layer where the upper chord is located is the upper layer. The specific construction steps include: S1. Construction flow section division; The current layer and the upper layer are divided into construction flow sections as a whole. The area where the cantilever steel structure is located is divided into the cantilever area, the area corresponding to the cantilever area in the longitudinal direction and the area adjacent to the cantilever area in the transverse direction by at least one span are divided into the cantilever adjacent area, and the area other than the cantilever area and the cantilever adjacent area is divided into the conventional construction area; S2a, construction of steel columns and beams closest to the cantilever area; In the cantilever adjacent area, the four steel columns closest to the cantilever area in the longitudinal and transverse directions and the steel beams between the columns are installed and welded first to form a stable frame structure; S2b, carry out the upper floor slab formwork and steel bar binding construction simultaneously; S3a, cantilever steel structure construction; The construction of cantilever steel structure starts when the following construction conditions are met; Condition 1: The pouring of the floor slab is completed; Condition 2: The welding of the four steel columns closest to the cantilever area and the steel beams between the columns is completed; Condition 3: Pour concrete into the four steel columns closest to the cantilever area to the level below the current level; The construction sequence of the cantilever steel structure is: install and weld in the order of lower chord, diagonal rod, vertical rod, upper chord, diagonal web rod, inner cross beam, outer lower chord rod and edge beam; S3b, pouring concrete for the upper floor slab simultaneously; S4, pouring of floor slab in cantilevered area; After the cantilever steel structure construction is completed and the upper floor slab is poured, the cantilever area floor slab will be poured.

2. A super high-rise large-span cantilever steel structure construction method according to claim 1, characterized in that: The steel beam in step S2 is a profiled steel beam.

3. The method for constructing a super high-rise large-span cantilevered steel structure according to claim 1, characterized in that: The step S2a specifically includes: S2a1, steel column lifting; S2a2, after the steel column is in place, use the jack for correction; S2a3, temporary fixation after steel column correction; S2a4, lifting of steel beams; S2a5, align the steel beams and temporarily fix them; S2a6, welding of steel columns and steel beams; The step S2b specifically includes: S2b1, upper floor slab formwork construction; Construction begins after step S2a3 is completed and is carried out simultaneously with the subsequent steps of S2a3; S2b2, beam and slab reinforcement binding of upper floor; After step S2a5 is completed, construction begins and is performed simultaneously with the subsequent steps of S2a5.

4. The method for constructing a super high-rise large-span cantilevered steel structure according to claim 1, characterized in that: The step S3a specifically includes: S3a1, installation of lower chord and diagonal rod; The lower chord and the diagonal rod are assembled on the ground, and the joints are fixed with temporary connecting plates and bolts. After assembly, they are hoisted as a whole, and welded immediately after hoisting in place and calibration. After the non-destructive test is passed, the subsequent steps are carried out; S3a2, pole installation; S3a3, string installation; The end of the upper chord is provided with an extension section, which is used as an installation point for the fall chain and the wire rope in subsequent steps; S3a4, diagonal brace installation; S3a5, inner crossbeam installation; S3a6, installation of outer lower chord and edge beam; Install the outer lower chord first, then install the edge beam; Before installation, determine the diagonal tension value based on construction simulation and select corresponding specifications of fall chains and wire ropes; During installation, fix the upper end of the fall chain to the extension section of the upper chord, adjust and correct it through the fall chain, connect the wire rope after correction, and remove the fall chain and wire rope after welding.

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