Construction method for installing elevator shaft structure on assembly type steel pipe truss

Abstract

A construction method of an assembled steel pipe truss additionally provided with an elevator shaft structure comprises the following steps that S1, the section height and width of a chord member (main pipe) and a web member (branch pipe) of a truss are determined, and the included angle, the section width ratio and the wall thickness of the branch pipe and the main pipe in a K-shaped node in the truss are set; two branch pipes of the K-shaped joint are arranged in a clearance manner and are tubular joints with one surfaces of the branch pipes and the main pipe being flush with each other; s2, the steel pipes are welded in a factory; s3, bolt end plates and I-shaped steel beams with proper sizes are selected, and the bolt end plates and the I-shaped steel beams are welded in a factory; s4, the overall structure of each truss is designed and constructed according to the existing structure of the house, and the trusses, the I-shaped steel beams with the end plates and the unilateral bolts are conveyed to a construction site; and S5, each frame and the I-shaped steel beams with the end plates are connected through unilateral bolts, and the elevator shaft frame structure is formed. The construction difficulty is reduced, the construction and transportation efficiency is improved, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of civil engineering structure construction. Based on the basic principles of steel structure, the bearing capacity theory of steel tube intersection nodes and the bearing capacity theory of bolt end plate nodes, a design method for a "steel tube truss + steel frame" type elevator shaft structure formed by two plane steel tube trusses through an H-shaped steel beam is proposed. The structural features are as follows: the chord and web of the plane steel tube truss are both rectangular steel tubes, and the web and chord are almost flush on one side. The steel tube truss node is an eccentric K-shaped gap-type intersection node. The two plane steel tube trusses are connected to the H-shaped steel beam with welded end plates at both ends by single-sided bolts to form a steel frame of steel tube column (the chord in the truss also serves as a column)-H-shaped steel beam. In this way, an elevator shaft structure is formed in which the force mode of the steel tube truss is perpendicular to the existing building construction direction and the force mode of the steel frame (steel tube column-H-shaped steel beam) is parallel to the existing building construction direction. The structure can realize different elevator shaft installation schemes according to different requirements such as building height. Background Art

[0002] Many old communities have the problem of inconvenience in going up and down stairs, so installing elevators in old communities has become an important livelihood task. In order to reduce the impact on existing old community buildings and to improve the construction efficiency of installing elevator shaft structures, steel structures independent of existing building structures are often used to install elevator shaft structures. Since it is located outside the existing building, the steel structure for installing the elevator should have sufficient bearing capacity and lateral stiffness to withstand wind loads and other effects. At the same time, the roads in old communities are narrow and the space is small, and large construction equipment is often difficult to enter. Therefore, the designed steel structure for installing the elevator should have the advantages of high lateral stiffness, high bearing capacity, and convenient transportation and construction.

[0003] Nowadays, more and more steel structures for adding elevator shafts have been put into use, but there are currently fewer types of elevator shaft structures, mostly angle steel trusses and steel frame structures. Taking the existing steel pipe frame for adding elevator shafts as an example, its space frame structure is completed in the processing plant or completed in two sections (when the truck is not long enough), and then transported to the site for splicing. Because it is a space frame, the truck space utilization efficiency is low, so the transportation efficiency is low. In addition, the nodes of the steel pipe frame structure are similar to the T-shaped rectangular steel pipe intersection node, and the node bearing capacity and node stiffness (it is difficult to achieve a rigid node) are both low. Secondly, the steel pipe frame structure for adding elevator shafts has a large aspect ratio and weak lateral stiffness of the overall structure. When it is subjected to large wind loads or earthquakes, it often requires support from existing buildings, thereby generating additional forces on existing buildings. To meet the overall bearing capacity and stiffness requirements of the frame, it is often necessary to strengthen the nodes, or enhance the cross-section and wall thickness of the steel pipe columns (beams), etc., resulting in increased costs and waste of materials. The present invention makes full use of the strength theory of steel pipe nodes, maximizes the conditions such as bearing capacity, construction efficiency, material utilization rate, etc., and can meet the construction needs of installing elevator shafts in different situations to the greatest extent. Summary of the invention

[0004] In order to overcome the deficiencies of the existing installation of elevator shafts in the construction of many problems, the present invention provides a construction method for installing an elevator shaft structure with an assembled steel pipe truss, which reduces the construction difficulty, improves the construction and transportation efficiency, and reduces the cost.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A construction method for installing an elevator shaft structure on an assembled steel tube truss comprises the following steps:

[0007] Step S1, according to the height of the existing building, and the bearing capacity and stiffness requirements of the elevator shaft, the cross-sectional height and cross-sectional width of the chord and web members of the steel tube truss are determined as h0×b0 and h1×b1, the chord is the main pipe, the web member is the branch pipe, and the steel tube truss adopts a K-shaped eccentric intersecting node in which the branch pipe and the main pipe are flush on one side, in order to make the surface of the elevator shaft structure flush and convenient for laying the wall. The angle θ between the branch pipe and the main pipe in the K-shaped node, the ratio of the cross-sectional width of the branch pipe to the main pipe β, and the wall thickness of the main pipe and the branch pipe are t0 and t1;

[0008] Step S2, welding the main pipe and the branch pipe in the factory, using fillet welds for welding, and setting the length, thickness and strength design values ​​of the welds;

[0009] Step S3, selecting bolt end plates and I-beams of appropriate sizes;

[0010] Step S4, design and construct each truss structure according to the existing structure of the house and the available outdoor space, and transport the truss, I-beams with end plates at both ends, and single-sided bolts to the construction site to prepare for the next step of construction;

[0011] Step S5, use single-sided bolts to connect two steel trusses and I-beams to form an integrated elevator shaft structure. One direction of the elevator shaft structure is a steel pipe truss structure, and the direction perpendicular to the truss is a steel pipe column-I-beam frame structure. The main pipe in the truss also serves as a steel pipe column, completing the design and construction of the overall space elevator shaft structure.

[0012] Furthermore, in step S1, the angle between the branch pipe and the main pipe in the K-shaped node is 45°, the ratio of the cross-sectional width of the branch pipe to the main pipe β is 0.6, and the wall thickness t0 and t1 of the main pipe and the branch pipe are 6 to 8 mm. The inner diameter r1 of the external fillet of the main pipe and the main pipe is the same as the wall thickness, and the outer diameter r2 is twice r1; the two branches of the K-shaped node adopt a gap setting, and the branch pipe is connected in the form of an eccentric intersecting node with one side flush with the main pipe; the axial force transmitted by the two branches is less than the bearing capacity of the eccentric intersecting node. Considering that there is no calculation formula for the bearing capacity of the eccentric intersecting node in the current specification, but the bearing capacity of the eccentric intersecting node is often higher than that of the same traditional steel pipe intersecting node, the bearing capacity of the eccentric intersecting node of the K-shaped steel pipe can be calculated according to the bearing capacity formula of the traditional K-shaped intersecting node in the "Steel Structure Design Standard" (GB50017-2017) (i.e. the relevant provisions in Article 13.4.2-2), and the minimum value of the three formulas is taken.

[0013]

[0014]

[0015] In the formula, θ i is the angle between the branch pipe and the main pipe, β is the ratio of the cross-sectional height of the branch pipe to that of the main pipe, b is the cross-sectional width of the main pipe, t is the cross-sectional wall thickness of the main pipe, f is the design value of the branch pipe strength, ψ n When the main pipe is under compression, the above formula is used for calculation. When it is under tension, it is taken as 1.0. σ is the larger absolute value of the axial compressive stress of the main pipe on both sides of the node. A v is the shear area of ​​the main pipe, f v b is the design value of shear strength of the main steel; i ,h i , t i are the cross-sectional width, height and wall thickness of the i-th branch pipe, b ei is the effective width of the cross section of the i-th branch, f i It is the design value of tensile (compressive and bending) strength of branch pipe steel.

[0016] Preferably, the main pipe is a rectangular main pipe, and the branch pipe is a rectangular branch pipe.

[0017] Furthermore, in step S2, the length, thickness and strength design value of the weld are calculated according to the strength of the weld required in the "Steel Structure Design Standard" (GB50017-2017) (i.e., the relevant formula in 13.4.5), and the formula is as follows:

[0018]

[0019] Where N i h is the design value of the branch pipe axial force; e is the calculated thickness of the fillet weld. When the branch pipe is subjected to axial force, the average calculated thickness can be taken as 0.7hf ,h f is the weld size; l w is the calculated length of the weld; is the strength design value of the fillet weld;

[0020] For gap-type K-nodes and θ i ≤50°,

[0021]

[0022] In the formula, θ i is the angle between the branch pipe and the main pipe, b i ,h i are the cross-sectional width and height of the i-th branch respectively.

[0023] Furthermore, in step S3, the height H of the I-beam, the width B of the upper and lower flanges, and the thickness t of the web and flange are first determined according to the overall structural calculation results and construction requirements. w , tf, and weld the I-beam to the bolt end plate in the factory; the welding requirements are consistent with step S2, wherein, according to the relevant provisions of 12.3.6 and 12.3.7 of the "Standard for Design of Steel Structures" (GB50017-2017), the bolt end plate adopts an extended end plate, the thickness of the bolt end plate is not less than the diameter of the bolt, and the bolt thickness and the bolt end plate diameter are obtained according to calculation; the single-sided bolt is calculated according to the strength of the bolt, the thickness of the bolt end plate is relatively consistent with the thickness of the main pipe, and is 6 to 8 mm, and the diameter of the single-sided bolt is 6 to 8 mm.

[0024] The technical concept of the present invention is as follows: first, in order to solve the problems of construction difficulties and low welding quality in old residential areas, the present invention proposes a design method of adding an elevator shaft structure of "steel tube truss + steel frame" formed by two plane steel tube trusses through H-shaped steel beams, forming an elevator shaft structure with a force mode of steel tube truss in the vertical direction of the existing building and a force mode of steel frame (steel tube column-H-shaped steel beam) in the parallel direction of the existing building, wherein the H-shaped steel beam is welded with the bolt end plate in the factory and connected on site with single-sided bolts. Such a construction method has the following advantages: ① The welding construction of the truss and the bolt end plate is completed in the factory, which can effectively improve the efficiency and quality of welding; ② At the construction site, only each truss needs to be connected with an I-beam with a bolt end plate, which greatly reduces the construction difficulty and improves the efficiency of on-site construction; ③ The assembled structure composed of single-sided bolts replaces the original welded structure, which improves the stiffness of the node, solves the problem of closed section and beam connection, and improves the construction efficiency. ④ The spatial structure that was originally welded in the factory is simplified into a plane structure, which can effectively improve transportation efficiency and reduce costs. Secondly, in view of the insufficient bearing capacity of the T-type node and the waste of material use, the present invention proposes a design that replaces the T-type node with a K-shaped eccentric steel pipe intersecting node. The advantages of using a gap-type K-shaped eccentric intersecting node are: ① Effectively improve the bearing capacity and stiffness of the node. ② Improve the lateral stiffness of the overall structure, so that it can better withstand external forces such as wind loads and earthquake loads. ③ The use of an eccentric node with a flat side can make the construction of the exterior wall more convenient.

[0025] The beneficial effects of the present invention are mainly manifested in: 1. A design method for an elevator shaft structure of "steel tube truss + steel frame" formed by two plane steel tube trusses through H-shaped steel beams is proposed, which optimizes the stress mode of the overall structure, improves the bearing capacity and lateral stiffness of the overall structure of the elevator shaft, and reduces the impact on the original building; 2. The original spatial structure of the factory construction is simplified into a plane structure, which improves the efficiency of transportation; 3. The gap-type K-shaped eccentric intersecting nodes are used to replace the original node structure, which improves the bearing capacity of the nodes and the flatness of the frame facade, which is convenient for the construction of the exterior wall. 4. The use of single-sided bolts to connect steel tube columns and I-beams with end plates solves the problem of closed section and beam connection and improves construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the overall structure of the elevator shaft with K-shaped node prefabricated trusses.

[0027] Figure 2 Schematic diagram of the detailed structure of the K-shaped node, where (a) is the elevation view of the K-shaped node, (b) is the cross-sectional view of the K-shaped node, and (c) is the cross-sectional view of the K-shaped node at section 1-1; 1 is the main pipe and 2 is the branch pipe.

[0028] Figure 3 Detailed structural diagram of a bolt end plate, a single-sided bolt, and an I-beam connection, where (a) is a vertical view of the connection structure, and (b) is a cross-sectional view of the connection structure; 3 is a bolt end plate, 4 is a single-sided bolt, and 5 is an I-beam.

[0029] Figure 4 This is a schematic diagram of the K-shaped node in the finite element analysis software.

[0030] Figure 5 Schematic diagram of the deformation of the K-shaped node when it is subjected to axial force (one end is under tension and the other end is under compression).

[0031] Figure 6 Comparison of the bearing capacity of K-shaped eccentric nodes and T-shaped eccentric nodes. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings.

[0033] Reference Figure 1 to Figure 6 , a construction method for adding an elevator shaft structure to an assembled steel tube truss, comprising the following steps:

[0034] Step S1, according to the existing building structure and the bearing capacity and stiffness requirements of the added elevator shaft structure, the cross-sectional height and cross-sectional width of the chord and web of the steel tube truss h0×b0, h1×b1 are determined. The chord is the main pipe, and the web is the branch pipe. The steel tube truss adopts a K-shaped eccentric gap type intersecting node in which the branch pipe and the main pipe are flush on one side, in order to make the surface of the added elevator shaft structure flush and convenient for laying the wall. The angle θ between the branch pipe and the main pipe in the K-shaped node is set to i Take 45°, the ratio of the cross-sectional width of the branch pipe to the main pipe β is 0.6, and the wall thickness t0 and t1 of the main pipe and branch pipe are 6 to 8mm. The inner diameter r1 of the external fillet of the main pipe and the branch pipe is the same as the wall thickness, and the outer diameter r2 is twice r1; the two branches of the K-shaped node adopt a gap setting, and the branch pipe is connected in the form of an eccentric intersecting node with one side flush with the main pipe; the axial force transmitted by the two branches should be less than the bearing capacity of the eccentric intersecting node. Considering that there is no calculation formula for the bearing capacity of the eccentric intersecting node in the current specification, but the bearing capacity of the eccentric intersecting node is often higher than that of the same traditional steel pipe intersecting node, the bearing capacity of the K-shaped steel pipe eccentric intersecting node is calculated according to the bearing capacity formula of the traditional K-shaped intersecting node in the "Steel Structure Design Standard" (GB50017-2017) (that is, the relevant provisions in Article 13.4.2-2), and the minimum value of the three formulas is taken.

[0035]

[0036] In the formula, θ iis the angle between the branch pipe and the main pipe, β is the ratio of the cross-sectional height of the branch pipe to that of the main pipe, b is the cross-sectional width of the main pipe, t is the cross-sectional wall thickness of the main pipe, f is the design value of the branch pipe strength, ψ n When the main pipe is under compression, the above formula is used for calculation. When it is under tension, it is taken as 1.0. σ is the larger absolute value of the axial compressive stress of the main pipe on both sides of the node. A v is the shear area of ​​the main pipe, f v b is the design value of shear strength of the main steel; i ,h i , t i are the cross-sectional width, height and wall thickness of the i-th branch pipe, b ei is the effective width of the cross section of the i-th branch, f i It is the design value of tensile (compressive and bending) strength of branch pipe steel.

[0037] The main pipe is a rectangular main pipe, and the branch pipe is a rectangular branch pipe.

[0038] Step S2, welding the main pipe and the branch pipe in the factory, using fillet welds for welding, the length, thickness and strength design value of the weld are calculated according to the strength of the weld required in the "Steel Structure Design Standard" (GB50017-2017) (i.e., the relevant formula in 13.4.5), the formula is as follows:

[0039]

[0040] Where N i h is the design value of the branch pipe axial force; e is the calculated thickness of the fillet weld. When the branch pipe is subjected to axial force, the average calculated thickness can be taken as 0.7h f ,h f is the weld size; l w is the calculated length of the weld; is the strength design value of the fillet weld;

[0041] For gap-type K-nodes and θ i ≤50°,

[0042]

[0043] In the formula, θ i is the angle between the branch pipe and the main pipe, b i ,h i are the cross-sectional width and height of the i-th branch respectively.

[0044] Step S3, select bolt end plates and I-beams of appropriate sizes: First, determine the height H of the I-beam, the width B of the upper and lower flanges, and the thickness t of the web and flanges according to the overall structural calculation results and construction requirements. w, tf, and weld the I-beam to the bolt end plate in the factory; the welding requirements are consistent with step S2, wherein, according to the relevant provisions of 12.3.6 and 12.3.7 of the "Standard for Design of Steel Structures" (GB50017-2017), the bolt end plate adopts an extended end plate, the thickness of the bolt end plate is not less than the diameter of the bolt, and the bolt thickness and the bolt end plate diameter are obtained according to calculation; the single-sided bolt is calculated according to the strength of the bolt, the thickness of the bolt end plate is relatively consistent with the thickness of the main pipe, and is 6 to 8 mm, and the diameter of the single-sided bolt is 6 to 8 mm.

[0045] Step S4, design and construct the overall structure of each truss according to the overall structure of the house, and transport the truss, I-beam with end plate, and single-side bolts to the construction site to prepare for the next step of construction;

[0046] Step S5, single-sided bolts are used to connect two steel trusses and I-beams to form an integrated elevator shaft structure. One direction of the elevator shaft structure is a steel tube truss structure, and the direction perpendicular to the truss is a steel tube column-I-beam frame structure. The main pipe in the truss also serves as a steel tube column, completing the design and construction of the overall space elevator shaft structure.

[0047] Compared with the commonly used general T-node elevator shaft frame structure, the advantages of the present invention are: ① The K-shaped eccentric rectangular steel tube intersecting node is used to replace the conventional T-shaped central rectangular steel tube intersecting node, which greatly improves the bearing capacity of the node and facilitates the construction of the exterior wall. ② The spatial structure of the factory construction is simplified into a plane structure, which improves the transportation efficiency. ③ Each frame is connected with an I-beam with an end plate and a single-sided bolt, which effectively solves the problem of difficult bolt connection of closed sections. ④ The bearing capacity and lateral stiffness of the overall structure are improved, and the welding quality and construction efficiency are improved.

[0048] The contents described in the embodiments of this specification are merely enumerations of implementation forms of the inventive concept and are for illustrative purposes only. The protection scope of the present invention should not be considered to be limited to the specific forms described in this embodiment, and the protection scope of the present invention also extends to equivalent technical means that can be thought of by ordinary technicians in this field based on the inventive concept.

Claims

1. A construction method for installing an elevator shaft structure on an assembled steel tube truss, characterized in that: The method comprises the following steps: Step S1, according to the existing building height, as well as the bearing capacity and stiffness requirements of the elevator shaft structure, the cross-sectional height × width h0 × b0 and h1 × b1 of the chord and web members of the steel tube truss are determined. The chord is the main pipe, and the web member is the branch pipe. The steel tube truss adopts a K-shaped eccentric gap type intersecting node in which the branch pipe and the main pipe are flush on one side. The angle θ between the branch pipe and the main pipe in the K-shaped node is set to i , the ratio of the cross-sectional width of the branch pipe to the main pipe β, the wall thickness of the main pipe and the branch pipe are t0 and t1; Step S2, welding the main pipe and the branch pipe in the factory, using fillet welds for welding, and setting the length, thickness and strength design values ​​of the welds; Step S3, selecting bolt end plates and I-beams of appropriate sizes; Step S4, design and construct each truss structure according to the existing structure of the house and the available outdoor space, and transport the truss, I-beams with end plates at both ends, and single-sided bolts to the construction site to prepare for the next step of construction; Step S5, use single-sided bolts to connect two steel tube trusses and I-beams to form an integrated elevator shaft structure. One direction of the integrated elevator shaft structure is a steel tube truss structure, and the direction perpendicular to the truss is a steel tube column-I-beam frame structure. The main pipe in the truss also serves as a steel tube column, completing the design and construction of the integrated space elevator shaft structure.

2. A construction method for installing an elevator shaft structure on a prefabricated steel tube truss as claimed in claim 1, characterized in that: In step S1, the angle between the branch pipe and the main pipe in the K-shaped node is 45°, the ratio of the cross-sectional width of the branch pipe to the main pipe β is 0.6, and the wall thickness t0 and t1 of the main pipe and the branch pipe are 6 to 8 mm; the inner diameter r1 of the external fillet of the main pipe and the branch pipe is the same as the wall thickness, and the outer diameter r2 is twice r1; the two branches of the K-shaped node adopt a gap setting, and the branch pipe and the main pipe are connected in an eccentric intersecting node form with one side flush; the axial force transmitted from the two branches is less than the bearing capacity of the eccentric intersecting node, and the bearing capacity of the eccentric intersecting node of the K-shaped steel pipe is calculated according to the following formula, and the minimum value of the three formulas is taken, In the formula, θ i is the angle between the branch pipe and the main pipe, β is the ratio of the cross-sectional height of the branch pipe to that of the main pipe, b is the cross-sectional width of the main pipe, t is the cross-sectional wall thickness of the main pipe, f is the design value of the branch pipe strength, ψ n When the main pipe is under compression, the above formula is used for calculation. When it is under tension, it is taken as 1.

0. σ is the larger absolute value of the axial compressive stress of the main pipe on both sides of the node. A v is the shear area of ​​the main pipe, f v b is the design value of shear strength of the main steel; i ,h i , t i are the cross-sectional width, height and wall thickness of the i-th branch pipe, b ei is the effective width of the cross section of the i-th branch, f i It is the design value of tensile strength of branch pipe steel.

3. A construction method for installing an elevator shaft structure on a prefabricated steel tube truss as claimed in claim 1 or 2, characterized in that: The main pipe is a rectangular main pipe, and the branch pipe is a rectangular branch pipe.

4. A construction method for adding an elevator shaft structure to an assembled steel tube truss as claimed in claim 1 or 2, characterized in that: In step S2, the formulas for the length, thickness and strength design values ​​of the weld are as follows: Where N i h is the design value of the branch pipe axial force; e is the calculated thickness of the fillet weld. When the branch pipe is subjected to axial force, the average calculated thickness is 0.7h f ,h f is the weld size; l w is the calculated length of the weld; is the strength design value of the fillet weld; For gap type K-type node and θi≤50°, In the formula, θ i is the angle between the branch pipe and the main pipe, b i ,h i are the cross-sectional width and height of the i-th branch respectively.

5. A construction method for installing an elevator shaft structure on a prefabricated steel tube truss as claimed in claim 1 or 2, characterized in that: In step S3, the height H of the I-beam, the flange width B, and the thickness t of the web and flange are first determined according to the overall structural calculation results and construction requirements. w ,t f , and weld the I-beam to the bolt end plate in the factory; the bolt end plate adopts an extended end plate, the thickness of the bolt end plate is not less than the diameter of the bolt, and the bolt thickness and the bolt end plate diameter are obtained according to calculation; the single-sided bolt is calculated according to the strength of the bolt, the thickness of the bolt end plate is relatively consistent with the thickness of the main pipe, which is 6 to 8mm, and the diameter of the single-sided bolt is 6 to 8mm.

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