Frame column reverse construction method suitable for alternate tension and compression stress

Abstract

The invention provides a frame column reverse construction method suitable for tension and compression alternate stress, and relates to the technical field of frame column construction.A frame column is constructed through a reverse construction method, and by reserving frame column steel bars and connecting steel plates, preferentially constructing other layers of structures and reasonably configuring frame beam steel bars to serve as temporary cantilever beams; and after the main body structure forms an integral stress system and the deformation is stable, the frame column is constructed. The risks that the frame column is fractured and damaged when bearing huge tension in the early stage and is bent and unstable when bearing huge pressure in the later stage are effectively avoided, the additional pressure conducted to the steel beam at the bottom of the frame column is effectively reduced, and the structural safety redundancy is further improved; a temporary support does not need to be additionally arranged, so that construction is more convenient and faster, the construction cost is lower, meanwhile, the cracking risk of a beam plate connected with the frame column is avoided, and universality and economical efficiency are achieved in the aspect of solving the problem of complex stress deformation of a vertical component of a main body structure.

Description

Technical Field

[0001] The invention relates to the technical field of frame column construction, in particular to a reverse construction method for frame columns subjected to alternating tension and compression forces. Background Art

[0002] Since the beginning of this century, with the rapid development of my country's construction industry, large-span and high-clearance buildings have become increasingly popular, and higher technical requirements have been put forward for the stress and construction process of complex structures. The conventional construction method of building frame columns is the sequential construction method, which is carried out layer by layer from bottom to top. The pressure of the frame column gradually increases with the loading layer by layer, and it is always in a compressive state, which is consistent with the mechanical properties of its materials. However, for the horizontal components such as beams and slabs connected to the top and bottom ends of the frame column, the deformation difference is large, and the deformation difference changes dynamically with the layer-by-layer loading construction. During the construction process, when the top and bottom ends of the frame column are constrained by the horizontal components, the internal force is converted into tension and compression, and the conventional sequential construction method cannot meet the construction technical requirements. In the early stage, the deformation of the top of the frame column is smaller than the deformation of the bottom of the column, and the frame column is subjected to huge tension, causing its steel bars to yield and produce horizontal cracks; in the later stage, as the layer-by-layer loading construction is completed, the deformation of the top of the frame column is greater than the deformation of the bottom of the column, and the frame column is subjected to huge pressure, causing it to buckle and become unstable, and this pressure is transmitted downward, causing the steel beam at the bottom of the frame column to generate additional pressure. Therefore, it is particularly important to choose an appropriate construction method to avoid the influence of tension-compression conversion of internal forces in frame columns, reduce additional pressure, ensure project quality and facilitate construction. Summary of the invention

[0003] In response to the above-mentioned prior art, the present invention proposes a reverse construction method for frame columns subjected to alternating tension and compression forces, aiming to solve quality problems such as damage to the main structure caused by the change in the stress state of the frame columns caused by phased construction conditions, and can effectively improve the safety redundancy of the main structure.

[0004] The present invention provides a reverse construction method for frame columns subjected to alternating tension and compression forces, wherein the frame columns are assumed to be located between the Fth floor and the F+1th floor, and the method comprises the following steps: Step 1, F-layer structure construction: hoisting of F-layer steel structure, erection of support frame and formwork, welding of reserved connection steel plates on the upper flange of F-layer steel beam corresponding to the bottom of frame column, steel bar tying and concrete pouring; Step 2, F+1 layer structure construction: install temporary support facilities for the F+1 layer transfer beam that coordinates the deformation of the frame column top through the frame beam, hoist the F+1 layer rigid structure steel, set up the support frame and formwork, tie the steel bars, disconnect the bottom of the frame column longitudinal reinforcement from the F layer connecting steel plate, and set the F+1 layer frame beam steel bars connected to the frame column top according to the original design and the larger value of the temporary cantilever force envelope, and complete the concrete pouring outside the frame column; Step 3: The structural construction of the F+2 to F+4 floors is carried out in sequence: the structural construction of the F+2 to F+4 floors is completed in the order of hoisting of rigid structural steel, erection of support frames and formwork, tying of steel bars and pouring of concrete; Step 4: The structures of the F+1st and Fth floors are fully stressed and deformed in a coordinated manner: When the concrete strength of the structures of the F+1st and Fth floors reaches the design value, except for the temporary support facilities of the F+1st layer transfer beams that coordinate the deformation of the frame column tops, the support frames and formwork of the F+1st and Fth floors are removed from top to bottom, so that the horizontal components such as the beams and slabs of the F+1st and Fth floors can be fully stressed under the action of the deadweight of the structure and the live load of construction. The downward deformation value of the F+1st layer transfer beams that coordinate the deformation of the frame column tops is S1, and the downward deformation value of the F-layer steel beams corresponding to the frame column bottoms is S2; Step 5: The structures of the F+5th to F+nth floors are constructed in sequence: the structural steel hoisting, support frame and formwork erection, steel bar binding and concrete pouring are carried out in sequence. During this period, the support frame and formwork below the floor are removed from the F+2th floor to the F+nth floor in sequence, provided that the concrete strength of the floor structure reaches the design value; Step 6: Formation of the overall spatial structural force system from the F+1st floor to the F+nth floor: After the structural concrete strength of the F+nth floor reaches the design value and the supporting frame and formwork below it are removed, so that the overall spatial structural force system from the F+1st floor to the F+nth floor is formed, the temporary supporting facilities of the conversion beam of the F+1st floor that coordinates the deformation of the frame column top are removed; Step 7, the structures from the F+1st to the F+nth floors are left to rest for internal force redistribution: the structures from the F+1st to the F+nth floors are left to rest for internal force redistribution until the horizontal components such as beams and slabs of each floor are deformed to a stable state, and the downward deformation value of the conversion beam of the F+1st floor that coordinates the deformation of the frame column top is S3; Step 8. Construction of the frame column structure between the Fth floor and the F+1th floor: weld the bottom end of the longitudinal reinforcement of the frame column to the connecting steel plate of the Fth floor, set up the formwork, pour the concrete of the frame column, and remove the formwork after the concrete strength of the frame column reaches the design value.

[0005] Preferably, the connecting steel plates described in steps 1, 2 and 8 are made of Q345B or Q355B steel, with a height ≥5d+h+∆S, a width of d+30mm and a thickness of d; wherein d is the diameter of the longitudinal reinforcement of the frame column, h is the thickness of the reinforced concrete floor slab of the Fth layer, and ∆S is the maximum value of the deformation difference between the top and bottom of the frame column.

[0006] Preferably, the temporary support facilities described in steps 2, 4 and 6 are sand boxes or jacks.

[0007] Preferably, the deformation values ​​described in steps 4 and 7 should satisfy S2-S1≥3mm or S3-S2≥3mm.

[0008] Preferably, the design values ​​described in steps 4, 5, 6 and 8 are all determined by using the 28-day pressure strength report of the test blocks cured under the same conditions to determine whether the concrete strength reaches 100% of the design strength.

[0009] Preferably, the welding between the bottom end of the longitudinal reinforcement of the frame column and the Fth layer connecting steel plate described in step eight adopts double-sided welding 5d, where d is the diameter of the longitudinal reinforcement of the frame column.

[0010] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention adopts the reverse construction method to construct the frame columns during the main structure construction process, so that the horizontal components such as beams and slabs connected to the top and bottom ends of the frame columns are deformed independently to a stable state, avoiding the alternating tension and compression stress of the frame columns due to the deformation difference between the top and bottom ends, thereby solving the hidden dangers of frame column fracture, buckling instability, etc.; at the same time, it effectively reduces the additional pressure transmitted to the bottom steel beam of the frame column, and improves the structural safety redundancy.

[0011] 2. The present invention adopts the principle of taking the maximum value of the envelope to adjust the reinforcement of the frame beam so that it can not only meet the original design requirements but also serve as a temporary cantilever beam, thereby avoiding the risk of beam and slab cracking due to insufficient force on the frame beam during construction, and there is no need to add temporary supports to horizontal components such as beams and slabs, thereby reducing construction difficulty and measures costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a construction process flow and pre-condition process diagram of an embodiment of the present invention.

[0013] Figure 2 It is a schematic diagram of the structure when the Fth layer of the embodiment of the present invention is completed.

[0014] Figure 3 It is a schematic diagram of the node structure when the upper flange of the F-th layer steel beam corresponding to the bottom of the frame column of an embodiment of the present invention is completed by welding the reserved connection steel plate.

[0015] Figure 4 It is a schematic diagram of the structure when the construction of the F+1th layer is completed in the embodiment of the present invention.

[0016] Figure 5 It is a schematic diagram of the node structure when the welding of the bottom end of the longitudinal reinforcement of the frame column and the F-th layer connecting steel plate is completed in an embodiment of the present invention.

[0017] Figure 6 It is a schematic diagram of the structure when the construction of the F+2 to F+4 layers of the embodiment of the present invention is completed.

[0018] Figure 7It is a schematic diagram of the structure when the construction of the F+5th to F+nth layers of the embodiment of the present invention is completed.

[0019] Figure 8 It is a structural schematic diagram of the embodiment of the present invention when the sand box of the temporary support facility of the conversion beam for coordinating the deformation of the top of the frame column of the F+1th floor is removed.

[0020] Fig. 9 It is a schematic diagram of the structure when the concrete pouring of the frame columns from the Fth floor to the F+1th floor of the embodiment of the present invention is completed.

[0021] In the attached figure: 1—frame column; 2—Fth layer steel beam; 3—connecting steel plate; 4—F+1th layer transfer beam; 5—F+1th layer frame beam; 6—sand box; 7—Fth layer reinforced concrete floor slab; 8—longitudinal reinforcement of frame column. DETAILED DESCRIPTION

[0022] In order to better understand the technical means, creative features, objectives and effects achieved by the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0023] In the description of the present invention, it should be noted that the positional relationships indicated by terms such as “top”, “bottom”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside” etc. cited in this specification are based on the positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0024] like Figure 1-Figure 9 As shown, this embodiment provides a reverse construction method for frame columns subjected to alternating tension and compression forces, wherein the frame column 1 is located between the Fth floor and the F+1th floor, and comprises the following steps: Step 1: Construction of the F-layer structure: Figure 2 and Figure 3 As shown, the F-th floor steel structure is hoisted, the supporting frame and formwork are erected, and the upper flange of the F-th floor steel beam 2 corresponding to the bottom of the frame column 1 is reserved for connecting steel plates 3 by welding; the number of connecting steel plates 3 is the same as the number of longitudinal reinforcements 8 of the frame column, and Q345B steel is used, with a height ≥5d+h+∆S, a width of d+30mm, and a thickness of d; where d is the diameter of the longitudinal reinforcement 8 of the frame column 1, h is the thickness of the F-th floor reinforced concrete slab 7, and ∆S is the maximum value of the deformation difference between the top and bottom of the frame column 1; reinforcement binding and concrete pouring;

[0025] Step 2: Construction of the F+1 layer structure: Figure 4 As shown, the temporary supporting facility sand box 6 is installed on the F+1 layer transfer beam 4 that coordinates the deformation of the top of the frame column 1 through the frame beam 5, the F+1 layer rigid structural steel is hoisted, the supporting frame and the formwork are erected, the steel bars are tied, and the bottom end of the frame column longitudinal reinforcement 8 is disconnected from the connecting steel plate 3 of the F layer. The steel bars of the F+1 layer frame beam 5 connected to the top of the frame column 1 are set according to the original design and the larger value of the temporary cantilever force envelope, and the concrete pouring outside the frame column 1 is completed.

[0026] Step 3: Follow the steps to construct the F+2 to F+4 structures: Figure 6 As shown, the structural construction from the F+2th to the F+4th floors was completed in the order of hoisting of rigid structural steel, erection of support frames and formwork, tying of steel bars and pouring of concrete.

[0027] Step 4: The structures of the F+1st and Fth floors are fully stressed and deformed in a coordinated manner: When the concrete strength of the F+1st and Fth floors reaches the design value, except for the F+1st layer transfer beam 4 that coordinates the deformation of the top of the frame column 1 and retains the temporary support facility sand box 6, the support frames and formwork of the F+1st and Fth floors are removed from top to bottom, so that the horizontal components such as the beams and slabs of the F+1st and Fth floors can be fully stressed under the action of the deadweight of the structure and the live load of construction; the F+1st layer frame beam 5 connected to the top of the frame column 1 forms a temporary suspension The arm beam deforms cooperatively with the F+1th layer transfer beam 4, and the risk of beam and slab cracking caused by insufficient force is avoided through cantilever bearing, and there is no need to add temporary support, which reduces the construction difficulty and measure costs; the downward deformation value of the F+1th layer transfer beam 4 that coordinates the deformation of the top of the frame column 1 is S1=3.2mm, so that the downward deformation value of the F+1th layer frame beam 5 and the top of the frame column 1 is S1=3.2mm, and the downward deformation value of the F+1th layer steel beam 2 corresponding to the bottom of the F layer and the frame column 1 is S2=10.6mm.

[0028] Step 5: Follow the steps to construct the structures from the F+5th to the F+nth layers: Figure 7 As shown, the structural construction of the F+5th to F+nth floors was completed in the order of hoisting of rigid structural steel, erection of support frames and formwork, tying of steel bars and pouring of concrete. During this period, on the premise that the concrete strength of the floor structure reached the design value, the support frames and formwork below the floor were removed in sequence from the F+2th floor to the F+nth floor.

[0029] In this embodiment, the F+nth layer is the roofing layer.

[0030] Step 6: Formation of the overall spatial structural force system from the F+1st floor to the F+nth floor: After the structural concrete strength of the F+nth floor reaches the design value and the supporting frame and formwork below it are removed, so that the overall spatial structural force system from the F+1st floor to the F+nth floor is formed, the temporary supporting facility sand box 6 of the F+1st floor transfer beam 4 that coordinates the deformation of the top of the frame column 1 of the F+1st floor is removed, as shown in FIG. Figure 8 As shown; let the F+1th to F+nth floors as a whole transform from a temporary support force system to a self-bearing force system.

[0031] Step seven, the F+1 to F+n-th floor structures are left static for internal force redistribution: the F+1 to F+n-th floor structures are left static for internal force redistribution until the horizontal components such as beams and slabs on each floor are deformed to a stable state; the downward deformation value of the F+1-th floor transfer beam 4 that coordinates the deformation of the top of the frame column 1 is S3=16.9mm, so that the downward deformation value of the F+1-th floor frame beam 5 and the top of the frame column 1 is S3=16.9mm. At this point, the deformation of the top and bottom of the frame column 1 during the construction process has reached a stable state.

[0032] Step 8: Construction of frame column structure between Fth floor and F+1th floor: Figure 5 As shown, the bottom end of the frame column longitudinal reinforcement 8 is welded to the connection steel plate 3 of the Fth layer, using double-sided welding 5d, where d is the diameter of the frame column longitudinal reinforcement 8; the formwork is set up, and the concrete of the frame column 1 is poured. The formwork is removed after the concrete strength of the frame column 1 reaches the design value, as shown in FIG. Fig. 9 shown.

[0033] Among them, the deformation values ​​described in steps 4 and 7 satisfy S2-S1=10.6mm-3.2mm=7.4mm≥3mm and S3-S2=16.9mm-10.6mm=6.3mm≥3mm.

[0034] The design values ​​described in steps 4, 5, 6, and 8 all use the 28-day pressure strength report of the test blocks cured under the same conditions to determine whether the concrete strength has reached 100% of the design strength.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the guidance of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. A reverse construction method for frame columns subjected to alternating tension and compression forces, characterized in that: The frame column is set to be located between the Fth floor and the F+1th floor, comprising the following steps: Step 1, F-layer structure construction: hoisting of F-layer steel structure, erection of support frame and formwork, welding of reserved connection steel plates on the upper flange of F-layer steel beam corresponding to the bottom of frame column, steel bar tying and concrete pouring; Step 2, F+1 layer structure construction: install temporary support facilities for the F+1 layer transfer beam that coordinates the deformation of the frame column top through the frame beam, hoist the F+1 layer rigid structure steel, set up the support frame and formwork, tie the steel bars, disconnect the bottom of the frame column longitudinal reinforcement from the F layer connecting steel plate, and set the F+1 layer frame beam steel bars connected to the frame column top according to the original design and the larger value of the temporary cantilever force envelope, and complete the concrete pouring outside the frame column; Step 3: The structural construction of the F+2 to F+4 floors is carried out in sequence: the structural construction of the F+2 to F+4 floors is completed in the order of hoisting of rigid structural steel, erection of support frames and formwork, tying of steel bars and pouring of concrete; Step 4: The structures of the F+1st and Fth floors are fully stressed and deformed in a coordinated manner: When the concrete strength of the structures of the F+1st and Fth floors reaches the design value, except for the temporary support facilities of the F+1st layer transfer beams that coordinate the deformation of the frame column tops, the support frames and formwork of the F+1st and Fth floors are removed from top to bottom, so that the beams and slabs of the F+1st and Fth floors can be fully stressed under the deadweight of the structure and the live load of construction. The downward deformation value of the F+1st layer transfer beams that coordinate the deformation of the frame column tops is S1, and the downward deformation value of the F-layer steel beams corresponding to the frame column bottoms is S2; Step 5: The structures of the F+5th to F+nth floors are constructed in sequence: the structural steel hoisting, support frame and formwork erection, steel bar binding and concrete pouring are carried out in sequence. During this period, the support frame and formwork below the floor are removed from the F+2th floor to the F+nth floor in sequence, provided that the concrete strength of the floor structure reaches the design value; Step 6: Formation of the overall spatial structural force system from the F+1st floor to the F+nth floor: After the structural concrete strength of the F+nth floor reaches the design value and the supporting frame and formwork below it are removed, so that the overall spatial structural force system from the F+1st floor to the F+nth floor is formed, the temporary supporting facilities of the conversion beam of the F+1st floor that coordinates the deformation of the frame column top are removed; Step 7, the structures from the F+1st to the F+nth floors are left stationary for internal force redistribution: the structures from the F+1st to the F+nth floors are left stationary for internal force redistribution until the beams and slabs of each floor are deformed to a stable state, and the downward deformation value of the conversion beam of the F+1st floor that coordinates the deformation of the frame column top is S3; Step 8. Construction of the frame column structure between the Fth floor and the F+1th floor: weld the bottom end of the longitudinal reinforcement of the frame column to the connecting steel plate of the Fth floor, set up the formwork, pour the concrete of the frame column, and remove the formwork after the concrete strength of the frame column reaches the design value.

2. The reverse construction method for frame columns subjected to alternating tension and compression forces as claimed in claim 1, characterized in that: The connecting steel plates described in steps 1, 2 and 8 are made of Q345B or Q355B steel, with a height ≥ 5d+h+∆S, a width of d+30mm and a thickness of d; where d is the diameter of the longitudinal reinforcement of the frame column, h is the thickness of the reinforced concrete floor slab of the Fth layer, and ∆S is the maximum value of the deformation difference between the top and bottom of the frame column.

3. The reverse construction method for frame columns subjected to alternating tension and compression forces as claimed in claim 1 or 2, characterized in that: The temporary support facilities described in steps 2, 4 and 6 are sand boxes or jacks.

4. The reverse construction method for frame columns subjected to alternating tension and compression forces as claimed in claim 1 or 2, characterized in that: The deformation values ​​described in steps 4 and 7 should satisfy S2-S1≥3mm or S3-S2≥3mm.

5. The reverse construction method for frame columns subjected to alternating tension and compression forces as claimed in claim 1 or 2, characterized in that: The design values ​​described in steps 4, 5, 6, and 8 all use the 28-day pressure strength report of the test blocks cured under the same conditions to determine whether the concrete strength has reached 100% of the design strength.

6. The reverse construction method for frame columns subjected to alternating tension and compression forces as claimed in claim 1 or 2, characterized in that: The welding between the bottom end of the longitudinal reinforcement of the frame column and the Fth layer connecting steel plate described in step eight adopts double-sided welding 5d, where d is the diameter of the longitudinal reinforcement of the frame column.

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