Construction method of large cantilever steel and concrete combined truss

Abstract

The invention relates to the technical field of building construction, in particular to a construction method of a large cantilever steel and concrete combined truss. The method specifically comprises the following steps: S1, providing a plurality of column feet, and mounting the plurality of column feet on a concrete base at intervals; s2, two steel reinforced columns are provided, the two steel reinforced columns are hoisted and vertically installed on the two column feet in the same group, and concrete is poured to form vertical parts; s3, outer side inclined steel columns and inner side inclined steel columns are provided and installed on the corresponding steel reinforced columns, and concrete is poured to form inclined parts so that the vertical parts and the inclined parts can form a combined truss; and S4, the steps from S2 to S3 are repeated, and then a plurality of combined trusses distributed at intervals are formed on the concrete base layer. The combined truss has the beneficial effects that the steel rib columns, the outer side inclined steel columns and the inner side inclined steel columns are installed on the concrete base layer, concrete is poured on the outer side to form the combined truss, the total mass of the truss is reduced, meanwhile, material loss is reduced, the construction period is shortened, the construction cost is reduced, and construction is easy and convenient.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, in particular to a construction method of a large cantilever steel and concrete combined truss. Background Art

[0002] With the rapid development of construction technology, especially the growing demand for large cantilever and high-span buildings, the traditional construction method that relies solely on reinforced concrete structures is facing unprecedented challenges.

[0003] Existing concrete structures are heavy, with complicated construction processes, prone to common quality problems such as cracks and leakage, which are increasingly inadequate in the pursuit of large cantilevers and high spans in modern construction. Especially in the construction of landmark buildings such as large stadiums, these problems not only seriously restrict construction efficiency and cost control, but also pose a potential threat to the long-term safety and service life of the building.

[0004] Therefore, the present invention proposes a construction method for a large cantilever steel and concrete composite truss. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a construction method for a large cantilever steel and concrete composite truss to solve the problems that the existing large cantilever and high span modern building construction process is complicated and prone to cracks and leakage.

[0006] The technical solution to achieve the above purpose is:

[0007] The present invention provides a construction method for a large cantilever steel and concrete composite truss, which specifically comprises the following steps:

[0008] S1: providing a plurality of column feet, and installing the plurality of column feet at intervals on a concrete base, wherein two corresponding column feet form a group, and the two column feet in each group are distributed inside and outside the concrete base;

[0009] S2: providing two steel columns, hoisting and vertically installing the two steel columns to the two column feet of the same group, and pouring concrete on the two steel columns to form a vertical portion;

[0010] S3: providing an outer inclined steel column and an inner inclined steel column, hoisting the outer inclined steel column and the inner inclined steel column and installing them at an angle to the corresponding steel frame column, and fixing the upper end of the inner inclined steel column to the outer inclined steel column, pouring concrete on the outer inclined steel column and the inner inclined steel column to form an inclined portion, so that the vertical portion and the inclined portion form a combined truss;

[0011] S4: Repeat steps S2 to S3 to form a plurality of spaced composite trusses on the concrete base.

[0012] Furthermore, the concrete base is in the shape of a circular ring and its overall curvature is consistent with the designed curvature, and the plurality of combined trusses are in the shape of an ellipse as a whole on the concrete base.

[0013] Furthermore, the inner inclined steel column and the outer inclined steel column are both inclined toward the outside of the concrete base, and the inclination angle of the inner inclined steel column is greater than the inclination angle of the outer inclined steel column, so that the inclined parts of the multiple combined trusses are divergent as a whole.

[0014] Furthermore, before pouring the concrete base, a plurality of anchor bolts are provided, and the plurality of anchor bolts are arranged at intervals at the position to be constructed and enclosed in an ellipse, and then concrete is poured so that the anchor bolts are pre-buried in the concrete base;

[0015] After the concrete base reaches the designed strength, the column base is installed on the corresponding anchor bolts.

[0016] Furthermore, the specific installation steps of the steel column are as follows:

[0017] Hoist the steel column above the column foot, provide fixing bolts, and use the fixing bolts to vertically anchor the steel column on the column foot;

[0018] Providing a total station, using the total station to check the verticality and elevation of the steel column, and loosening the fixing bolts to adjust the posture of the steel column;

[0019] After the elevation and verticality are adjusted, tighten the fixing bolts to fix the steel column and the column base.

[0020] Furthermore, before the outer inclined steel column and the inner inclined steel column are hoisted, ear plates are welded on both sides of the corresponding steel frame column, and clamping plates matching the ear plates are welded on both sides of the outer inclined steel column and the inner inclined steel column;

[0021] When hoisting the outer inclined steel column and the inner inclined steel column, the ear plate is inserted into the corresponding clamping plate, connecting bolts are provided, and the connecting bolts are passed through the clamping plate and the ear plate to achieve the fixing of the outer inclined steel column and the inner inclined steel column;

[0022] Using the total station to check the elevation and inclination of the outer inclined steel column and the inner inclined steel column, and loosening the connecting bolts to adjust the postures of the outer inclined steel column and the inner inclined steel column;

[0023] After the elevation and the inclination are adjusted, the connections between the outer inclined steel column, the inner inclined steel column and the steel frame column are welded and fixed, and the ear plate and the clamping plate are removed.

[0024] Furthermore, a support frame is arranged between the two steel frame columns in each of the combined trusses and between the inner inclined steel column and the outer inclined steel column. When pouring concrete, the end of the support frame is buried in the concrete.

[0025] Furthermore, before casting the vertical portion and the inclined portion, steel bars and stirrups are provided and arranged on the steel frame column, the inner inclined steel column and the outer inclined steel column.

[0026] Furthermore, the density of the steel bars and stirrups at both ends of the steel frame column, the inner inclined steel column and the outer inclined steel column is higher than that in the middle, thereby forming a steel bar density zone to improve the structural strength of the composite truss.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] By installing steel columns, outer inclined steel columns and inner inclined steel columns on the concrete base and pouring concrete on the outside to form a composite truss, the total mass of the truss is reduced, while the loss of materials is reduced, energy conservation and environmental protection are achieved, the construction period is shortened, the construction cost is reduced, and the construction is simple.

[0029] The composite truss formed by mixing steel and concrete has a high fire resistance limit, which reduces the cost of anti-corrosion and protective measures and saves a lot of material and labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the construction process of the large cantilever steel and concrete composite truss of the present invention.

[0031] Figure 2 It is a schematic diagram of the overall structure of the large cantilever steel and concrete composite truss of the present invention.

[0032] Figure 3 It is a schematic diagram of the combined truss structure of the large cantilever steel and concrete combined truss of the present invention.

[0033] Legend: 1. Concrete base; 2. Composite truss; 3. Steel column; 4. Outer inclined steel column; 5. Inner inclined steel column. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0035] See also Figure 1The present invention provides a construction method of a large cantilever steel and concrete composite truss, which solves the problem that the existing large cantilever and high span modern building construction process is cumbersome, and is prone to cracks and leakage. By installing steel frame columns, outer inclined steel columns and inner inclined steel columns on the concrete base, and pouring concrete on the outside to form a composite truss, the total mass of the truss is reduced by setting the composite truss, while reducing the loss of materials, saving energy and protecting the environment, shortening the construction period, reducing construction costs, and simplifying the construction.

[0036] The composite truss formed by mixing steel and concrete has a high fire resistance limit, which reduces the cost of anti-corrosion and protective measures and saves a lot of material and labor costs.

[0037] The construction method of a large cantilever steel and concrete composite truss of the present invention is described below in conjunction with the accompanying drawings.

[0038] See also Figure 1 , showing a schematic diagram of the construction process of the large cantilever steel and concrete composite truss of the present invention. Figure 2 , showing the overall structural schematic diagram of the large cantilever steel and concrete composite truss of the present invention. Figure 3 , showing the combined truss structure schematic diagram of the large cantilever steel and concrete combined truss of the present invention. Figures 1 to 3 , a construction method of a large cantilever steel and concrete composite truss of the present invention is described.

[0039] like Figures 1 to 3 As shown, a construction method of a large cantilever steel and concrete composite truss of the present invention specifically includes the following steps:

[0040] S1: providing a plurality of column feet, and installing the plurality of column feet at intervals on the concrete base 1, and two corresponding column feet form a group, and the two column feet in each group are distributed inside and outside the concrete base 1;

[0041] S2: providing two steel columns 3, hoisting and vertically installing the two steel columns 3 on the two column feet of the same group, and pouring concrete on the two steel columns 3 to form a vertical portion;

[0042] S3: providing an outer inclined steel column 4 and an inner inclined steel column 5, hoisting the outer inclined steel column 4 and the inner inclined steel column 5 and installing them at an angle to the corresponding steel frame column 3, and fixing the upper end of the inner inclined steel column 5 on the outer inclined steel column 4, pouring concrete on the outer inclined steel column 4 and the inner inclined steel column 5 to form an inclined portion, so that the vertical portion and the inclined portion form a combined truss 2;

[0043] S4: repeating steps S2 to S3 to form a plurality of spaced composite trusses 2 on the concrete base 1.

[0044] In a specific embodiment, the concrete base layer 1 is in a circular shape and its overall curvature is consistent with the designed curvature, and the plurality of combined trusses 2 are in an overall elliptical shape on the concrete base layer 1 .

[0045] In a specific embodiment, the inner inclined steel column 5 and the outer inclined steel column 4 are both inclined toward the outside of the concrete base 1, and the inclination angle of the inner inclined steel column 5 is greater than the inclination angle of the outer inclined steel column 4, so that the inclined parts of the multiple combined trusses 2 are divergent as a whole.

[0046] In a specific embodiment, before pouring the concrete base 1, a plurality of anchor bolts are provided, the plurality of anchor bolts are arranged at intervals at the position to be constructed and enclosed in an ellipse, and then concrete is poured so that the anchor bolts are pre-buried in the concrete base 1;

[0047] After the concrete base 1 reaches the designed strength, the column foot is installed on the corresponding anchor bolt.

[0048] In a specific implementation, the specific installation steps of the steel column 3 are as follows:

[0049] Hoist the steel column 3 above the column foot, provide fixing bolts, and use the fixing bolts to vertically anchor the steel column 3 on the column foot;

[0050] Providing a total station, using the total station to check the verticality and elevation of the steel column 3, and loosening the fixing bolts to adjust the posture of the steel column 3;

[0051] After the elevation and verticality are adjusted, tighten the fixing bolts to fix the steel column and the column base.

[0052] In a specific embodiment, before the outer inclined steel column 4 and the inner inclined steel column 5 are hoisted, ear plates are welded on both sides of the corresponding steel frame column 3, and clamping plates matching the ear plates are welded on both sides of the outer inclined steel column 4 and the inner inclined steel column 5;

[0053] When the outer inclined steel column 4 and the inner inclined steel column 5 are hoisted, the ear plate is inserted into the corresponding clamping plate, and connecting bolts are provided, and the connecting bolts are passed through the clamping plate and the ear plate to achieve the fixing of the outer inclined steel column 4 and the inner inclined steel column 5;

[0054] Use the total station to check the elevation and inclination of the outer inclined steel column 4 and the inner inclined steel column 5, and loosen the connecting bolts to adjust the postures of the outer inclined steel column 4 and the inner inclined steel column 5;

[0055] After the elevation and inclination are adjusted, the connections between the outer inclined steel column 4, the inner inclined steel column 5 and the steel frame column 3 are welded and fixed, and the ear plate and the clamping plate are removed.

[0056] In a specific embodiment, a support frame is arranged between the two steel frame columns 3 and between the inner inclined steel column 5 and the outer inclined steel column 4 in each of the combined trusses 2. When pouring concrete, the ends of the support frame are buried in the concrete.

[0057] In a specific embodiment, before casting the vertical portion and the inclined portion, steel bars and stirrups are provided and arranged on the steel frame column 3 , the inner inclined steel column 5 , and the outer inclined steel column 4 .

[0058] In a specific embodiment, the density of the steel bars and stirrups at both ends of the steel frame column 3 , the inner inclined steel column 5 and the outer inclined steel column 4 is higher than that in the middle to form a steel bar density zone to improve the structural strength of the composite truss 2 .

[0059] The construction process of a large cantilever steel and concrete composite truss of the present invention is described in detail below.

[0060] Deepening design: According to the structural, architectural and other professional drawings, determine the main deepening contents of the composite truss 2, and establish a deepening BIM model based on the deepening drawings, and perform simulated lifting calculations, analyze the lifting process of the composite truss 2, and finally conduct an audit.

[0061] Processing and manufacturing: various parts of the combined truss 2 are processed.

[0062] Pre-embedded foundation: First, pre-embed the anchor bolts: Before pre-embedding, use the total station to mark the reference line of the pre-embedded position on the steel mesh of the concrete base 1 as the control basis for the preliminary installation of the anchor bolts. During the pre-embedding process, provide a positioning ring plate, place the positioning ring plate on the reference line, provide a positioning anchor plate, and weld the positioning anchor plate to the positioning ring plate. Then weld the anchor bolts to the positioning ring plate, and weld the bottom of the anchor bolts to the steel bar to prevent the anchor bolts from shifting when pouring concrete. After pouring concrete, re-measure the position of the anchor bolts, make timely adjustments if there is any deviation, and finally install the adjusting nuts and spacers.

[0063] Then install the column base onto the anchor bolts.

[0064] Then hoist the steel column 3 to the column foot, provide a truck crane, and the hoisting weight is 130t. Before hoisting, clean the slag and floating rust on the steel column 3 to ensure the cleanliness of the weld when the steel column 3 is butt-welded; set up a ladder and safety protection measures, and hang up a fall arrester. After hoisting in place, check and adjust the elevation and verticality of the steel column 3, and fix it after adjustment. Then support the template on the outside of the steel column 3, and pour concrete in the template to form a vertical part.

[0065] Then, the outer inclined steel column 4 and the inner inclined steel column 5 are welded and fixed on the steel frame column 3. Before welding and fixing, the elevation and inclination of the outer inclined steel column 4 and the inner inclined steel column 5 are checked, and after checking, they are adjusted, and then the outer inclined steel column 4 and the inner inclined steel column 5 are fixed. A formwork is supported on the outer side of the outer inclined steel column 4 and the inner inclined steel column 5, and concrete is poured into the formwork to form an inclined portion.

[0066] The above welding fixation adopts arc-initiating plate welding, and adopts segmented symmetrical welding method during the welding process, that is, two people weld at the same speed at the same time in symmetrical positions to ensure that the welding points on both sides of the material can be evenly stressed during the welding process.

[0067] When pouring concrete above, a vibrating rod is used to pour on one side of the structure.

[0068] During the above construction, a full-span support system is used, and support system deformation monitoring is set up: when pouring concrete, the support system is monitored, mainly monitoring the displacement and deformation of the bracket. After the construction of the combined truss 2 is completed, the support system is dismantled.

[0069] When setting up the operating platform on the steel column 3, the steel pipe used for setting up shall be 48×3mm; the height of the guardrail on the top of the operating platform shall not be less than 1.5m; a base or pad, longitudinal and transverse sweeping rods, vertical diagonal rods, and a platform steel springboard shall be set at the lower part of the operating platform uprights.

[0070] When the operating platform is set up on the outer inclined steel column 4 and the inner inclined steel column 5, the platform plate is an aluminum springboard, the platform beam and the diagonal brace section is L75*5, the safety pile is P48.3*3.6, and the material is Q235. The platform consists of a platform beam, a springboard, a guardrail, and a pole.

[0071] The present invention is described in detail above in conjunction with the embodiments of the accompanying drawings. A person skilled in the art can make various variations of the present invention according to the above description. Therefore, certain details in the embodiments should not constitute a limitation of the present invention, and the scope of protection of the present invention shall be defined by the scope of the attached claims.

Claims

1. A construction method for a large cantilever steel and concrete composite truss, characterized in that: The specific steps include: S1: providing a plurality of column feet, and installing the plurality of column feet at intervals on a concrete base (1), with two corresponding column feet forming a group, and the two column feet in each group being distributed inside and outside the concrete base (1); S2: providing two steel frame columns (3), hoisting and vertically installing the two steel frame columns (3) on the two column bases of the same group, and pouring concrete on the two steel frame columns (3) to form a vertical portion; S3: providing an outer inclined steel column (4) and an inner inclined steel column (5), hoisting the outer inclined steel column (4) and the inner inclined steel column (5) and installing them at an angle to the corresponding steel frame column (3), and fixing the upper end of the inner inclined steel column (5) on the outer inclined steel column (4), pouring concrete on the outer inclined steel column (4) and the inner inclined steel column (5) to form an inclined portion, so that the vertical portion and the inclined portion form a combined truss (2); S4: Repeat steps S2 to S3 to form a plurality of spaced composite trusses (2) on the concrete base (1).

2. The construction method of a large cantilever steel and concrete composite truss according to claim 1 is characterized in that: The concrete base (1) is in the shape of a circular ring and its overall curvature is consistent with the designed curvature; the plurality of combined trusses (2) on the concrete base (1) are in the shape of an ellipse as a whole.

3. The construction method of a large cantilever steel and concrete composite truss according to claim 2 is characterized in that: The inner inclined steel column (5) and the outer inclined steel column (4) are both inclined toward the outside of the concrete base layer (1), and the inclination angle of the inner inclined steel column (5) is greater than the inclination angle of the outer inclined steel column (4), so that the inclined parts of the plurality of combined trusses (2) are divergent as a whole.

4. The construction method of a large cantilever steel and concrete composite truss according to claim 2 is characterized by: Before pouring the concrete base (1), a plurality of anchor bolts are provided, the plurality of anchor bolts are arranged at intervals at the position to be constructed and enclosed in an ellipse, and then concrete is poured so that the anchor bolts are pre-buried in the concrete base (1); After the concrete base (1) reaches the designed strength, the column foot is installed on the corresponding anchor bolt.

5. The construction method of a large cantilever steel and concrete composite truss according to claim 1 is characterized in that: The specific installation steps of the steel column (3) are as follows: The steel frame column (3) is hoisted above the column foot, fixing bolts are provided, and the steel frame column (3) is vertically anchored on the column foot by using the fixing bolts; Providing a total station, using the total station to check the verticality and elevation of the steel column (3), and loosening the fixing bolts to adjust the posture of the steel column (3); After the elevation and verticality are adjusted, tighten the fixing bolts to fix the steel column and the column base.

6. The construction method of a large cantilever steel and concrete composite truss according to claim 5 is characterized in that: Before the outer inclined steel column (4) and the inner inclined steel column (5) are hoisted, ear plates are welded on both sides of the corresponding steel frame column (3), and clamping plates matching the ear plates are welded on both sides of the outer inclined steel column (4) and the inner inclined steel column (5); When the outer inclined steel column (4) and the inner inclined steel column (5) are hoisted, the ear plate is inserted into the corresponding clamping plate, and connecting bolts are provided, and the connecting bolts are passed through the clamping plate and the ear plate to achieve the fixing of the outer inclined steel column (4) and the inner inclined steel column (5); Using the total station to check the elevation and inclination of the outer inclined steel column (4) and the inner inclined steel column (5), and loosening the connecting bolts to adjust the postures of the outer inclined steel column (4) and the inner inclined steel column (5); After the elevation and inclination are adjusted, the connection between the outer inclined steel column (4), the inner inclined steel column (5) and the steel frame column (3) is welded and fixed, and the ear plate and the clamping plate are removed.

7. The construction method of a large cantilever steel and concrete composite truss according to claim 1 is characterized by: A support frame is arranged between the two steel frame columns (3) in each of the combined trusses (2) and between the inner inclined steel column (5) and the outer inclined steel column (4); when pouring concrete, the end of the support frame is buried in the concrete.

8. The construction method of a large cantilever steel and concrete composite truss according to claim 1 is characterized by: Before casting the vertical portion and the inclined portion, steel bars and stirrups are provided and arranged on the steel frame column (3), the inner inclined steel column (5) and the outer inclined steel column (4).

9. The construction method of a large cantilever steel and concrete composite truss according to claim 8 is characterized by: The density of the steel bars and stirrups at the two ends of the steel frame column (3), the inner inclined steel column (5) and the outer inclined steel column (4) is higher than that in the middle, thereby forming a steel bar density zone, which is used to improve the structural strength of the composite truss (2).

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