Fabricated steel pipe truss elevator shaft structure

Abstract

A kind of construction method of fabricated steel pipe truss elevator shaft structure, comprising the following steps: step S1, the section height and width of truss chord (main pipe) and web member (branch pipe) are determined, the angle of branch pipe and main pipe in K-shaped node in truss, the ratio of section width, wall thickness are set;K-shaped node two branch pipes are set using gap type, and it is flush with main pipe for branch pipe and main pipe one side interpenetrating node;Step S2, steel pipe is welded in factory;Step S3, the bolt end plate and I-beam of appropriate size are selected, and bolt end plate and I-beam are welded in factory;Step S4, according to the overall structure of each truss of house existing structure design and construction, and the truss, the I-beam of end plate, single-side bolt are transported to construction site;Step S5, single-side bolt is used to connect each frame and the I-beam of end plate, and form elevator shaft frame structure.The present application reduces construction difficulty, improves construction and transportation efficiency, and reduces cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of civil engineering structure construction, based on the basic principles of steel structure, the bearing capacity theory of steel pipe intersecting node and the bearing capacity theory of bolt end plate node, a design method of "steel pipe truss + steel frame" type elevator shaft structure formed by two plane steel pipe trusses through H-shaped steel beams is proposed; the structural characteristics are as follows: the chord and web of the plane steel pipe truss are both rectangular steel pipes, and the web and chord are almost flush on one side, the steel pipe truss node is an eccentric K-shaped gap type intersecting node, the two plane steel pipe trusses are connected through single-sided bolts and H-shaped steel beams with both ends welded end plates to form a steel pipe column (truss chord serving as column)-H-shaped steel beam steel frame, thus forming an elevator shaft structure with a steel pipe truss force mode perpendicular to the building direction of the existing building and a steel frame (steel pipe column-H-shaped steel beam) force mode parallel to the building direction of the existing building, which can realize different elevator shaft installation schemes according to different requirements such as building height. BACKGROUND

[0002] Many old communities have the problem of inconvenience in going up and down the building, so installing elevators in old communities has become an important livelihood project. In order to reduce the impact on the existing old community building structure and to improve the construction efficiency of the elevator shaft structure, many times the steel structure independent of the existing building structure is used to install the elevator shaft structure. Since it is located outside the existing building, the elevator steel structure should have sufficient bearing capacity and lateral stiffness to resist wind load and other actions. At the same time, the roads in old communities are narrow and the space is small, so large construction equipment often cannot enter, so the designed elevator steel structure should have high lateral stiffness, high bearing capacity, convenient transportation and construction, etc.

[0003] Nowadays, more and more elevator shaft steel structures are put into use, but the types of elevator shaft structures are few, mostly angle steel trusses and steel frame structures. Taking the existing elevator shaft steel pipe frame as an example, the space frame structure is completed in the processing plant or two sections (when the truck length is not enough), and then transported to the site for splicing. Since it is a space frame, the truck space utilization efficiency is low, so the transportation efficiency is low. In addition, the node of the steel pipe frame structure is similar to the T-shaped rectangular steel pipe intersecting node, and the node bearing capacity and node stiffness (it is difficult to achieve rigid node) are low. Secondly, the elevator shaft steel pipe frame structure has a large height-width ratio and weak overall lateral stiffness, and when subjected to large wind load or earthquake action, it often needs to be supported by the existing building, thereby generating additional force on the existing building. In order to meet the overall bearing capacity and stiffness requirements of the frame, it is often necessary to strengthen the node, or increase the section and wall thickness of the steel pipe column (beam), resulting in rising costs and waste of materials. The present application makes full use of the strength theory of steel pipe nodes to maximize the bearing capacity, construction efficiency and material utilization, and can maximize the construction requirements of elevator shaft installation under different conditions. SUMMARY

[0004] In order to overcome the problems of the existing elevator shafts, the application provides a construction method of the assembled steel pipe truss elevator shaft structure, which reduces the construction difficulty, improves the construction and transportation efficiency, and reduces the cost.

[0005] The application adopts the technical scheme to solve the technical problems:

[0006] The construction method of the assembled steel pipe truss elevator shaft structure comprises the following steps:

[0007] Step S1, according to the height of the existing house, and the bearing capacity and stiffness requirement factors of the elevator shaft, the section height and section width h0×b0, h1×b1 of the chord and web of the steel pipe truss are determined, the chord is the main pipe, and the web is the branch pipe, the steel pipe truss adopts K-shaped eccentric intersecting nodes with the branch pipe and the main pipe in one plane, so that the outer surface of the elevator shaft structure is flat and convenient for laying the wall surface, the included angle θ of the branch pipe and the main pipe in the K-shaped node, the ratio β of the section width of the branch pipe and the main pipe, and the wall thickness t0 and t1 of the main pipe and the branch pipe are set;

[0008] Step S2, the main pipe and the branch pipe are welded in the factory, the fillet weld is used for welding, and the length, thickness and strength design value of the weld are set;

[0009] Step S3, the bolt end plate and the I-beam with appropriate sizes are selected;

[0010] Step S4, according to the existing structure of the house and the available outdoor space, each truss structure is designed and constructed, and the truss, the I-beam with end plates at both ends and the single-sided bolt are transported to the construction site, and the next step of construction is prepared;

[0011] Step S5, the two steel trusses and the I-beam are connected by the single-sided bolt to form an integral elevator shaft structure, one direction of the elevator shaft structure is the steel pipe truss structure, and the vertical direction of the truss is the steel pipe column-I-beam frame structure, the main pipe in the truss serves as the steel pipe column, and the design and construction of the integral space elevator shaft structure are completed.

[0012] Further, in the step S1, the included angle of the branch pipe and the main pipe in the K-shaped node is 45°, the ratio β of the cross-sectional width of the branch pipe and the main pipe is 0.6, and the wall thickness t0 and t1 of the main pipe and the branch pipe is 6-8 mm. The main pipe and the main pipe are externally rounded, the inner diameter r1 is the same as the wall thickness, and the outer diameter r2 is twice the r1; the two branch pipes of the K-shaped node adopt a gap type setting, and the connection form of the branch pipe and the main pipe is flush on one side of the eccentric intersecting node; the axial force transmitted by the two branch pipes is less than the bearing capacity of the eccentric intersecting node, and the current specification does not have a formula for calculating the bearing capacity of the eccentric intersecting node, but the bearing capacity of the eccentric intersecting node is often higher than that of the traditional steel pipe intersecting node, so the bearing capacity of the K-shaped steel pipe eccentric intersecting node 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 item 13.4.2-2), and the minimum value of the three formulas is taken,

[0013]

[0014]

[0015] wherein θ is the included angle of the branch pipe and the main pipe, β is the ratio of the cross-sectional height of the branch pipe and 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 strength design value of the branch pipe, ψ i is the included angle of the branch pipe and the main pipe, β is the ratio of the cross-sectional height of the branch pipe and 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 strength design value of the branch pipe, ψ n is calculated according to the above formula when the main pipe is in compression, and is 1.0 when it is in tension, 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 is the shear strength design value of the main pipe steel; b 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 cross-sectional width of the i-th branch pipe, f i is the tensile (compressive and bending) strength design value of the branch pipe steel.

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

[0017] Further, in the 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] wherein N i is the axial force design value of the branch pipe; h e is the calculation thickness of the fillet weld, and the average calculation thickness can be taken as 0.7h when the branch pipe bears the axial forcef , 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 joints and θ i ≤ 50°,

[0021]

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

[0023] Further, in the step S3, first, the height H of the I-beam, the width B of the upper and lower flanges, and the thickness t w , tf of the web and the flange are determined according to the overall structure calculation result and the construction requirement, and the I-beam is welded with the bolt end plate in the factory; the welding requirement is consistent with that of step S2, wherein according to the relevant provisions of 12.3.6 and 12.3.7 of the Steel Structure Design Standard (GB50017-2017), the bolt end plate adopts an overhanging end plate, the thickness of the bolt end plate is not less than the diameter of the bolt, and the thickness of the bolt and the diameter of the bolt end plate are calculated; the single-side bolt is calculated according to the strength of the bolt, the thickness of the bolt end plate and the thickness of the main pipe are kept relatively consistent, which is 6 to 8 mm, and the diameter of the single-side bolt is 6 to 8 mm.

[0024] The technical concept of the present application is: firstly, aiming at the problems of old community construction difficulty, low welding quality and the like, the present application proposes a design method of a "steel pipe truss + steel frame" type elevator shaft structure with an additional installation formed by two plane steel pipe trusses through H-shaped steel beams, forming an elevator shaft structure with an additional installation with a vertical existing building direction as a steel pipe truss stress mode and a parallel existing building direction as a steel frame (steel pipe column-H-shaped steel beam) stress mode, wherein the H-shaped steel beam is welded with a bolt end plate in a factory, and is connected on site by using a single-side bolt. Such a construction method has the following advantages: ①the welding of the truss and the bolt end plate is completed in the factory, which can effectively improve the welding efficiency and quality; ②only the bolted end plate I-shaped steel is needed to connect each truss on the construction site, which greatly reduces the construction difficulty and improves the efficiency of the on-site construction; ③the assembled structure composed of single-side bolts replaces the original welded structure, improves the stiffness of the joint, solves the problem of closed section and beam connection, and improves the construction efficiency. ④the space structure originally constructed and welded in the factory is simplified to a plane structure, which can effectively improve the transportation efficiency and reduce the cost. Secondly, aiming at the insufficient bearing capacity of the T-shaped node and the waste of materials, the present application proposes a design of using a K-shaped eccentric steel pipe intersecting node to replace the T-shaped node. The advantages of using the gap type K-shaped eccentric intersecting node are: ①the bearing capacity and stiffness of the node are effectively improved. ②the lateral stiffness of the overall structure is improved, so that it can better withstand wind load, seismic load and other external forces. ③the one-side flush eccentric node can make the construction of the outer wall surface more convenient.

[0025] The beneficial effects of the present application mainly include: 1, a design method of a "steel pipe truss + steel frame" type elevator shaft structure with an additional installation formed by two plane steel pipe 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 with an additional installation, and reduces the influence on the original building; 2, the space structure originally constructed in the factory is simplified to a plane structure, which improves the transportation efficiency; 3, the gap type K-shaped eccentric intersecting node is used to replace the original node structure, which improves the bearing capacity of the node and the flatness of the frame facade, facilitating the construction of the outer wall surface. 4, the single-side bolt is used to connect the steel pipe column and the I-shaped steel beam with an end plate, which solves the problem of closed section and beam connection and improves the construction efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The overall structure of the K-shaped node assembled truss elevator shaft with an additional installation is shown in the figure.

[0027] Figure 2 The K-shaped node detail structure is shown in the figure, wherein (a) represents the K-shaped node elevation view, (b) represents the K-shaped node section view, and (c) represents the K-shaped node section view at 1-1 section; 1 is a main pipe, and 2 is a branch pipe.

[0028] Figure 3 Figure 3 is a detail structural drawing of a bolt end plate, a single-side bolt and an I-beam connection, wherein (a) is a connection structural elevation view, and (b) is a connection structural section view; 3 is a bolt end plate, 4 is a single-side bolt, and 5 is an I-beam.

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

[0030] Figure 5 Figure 5 is a schematic diagram of deformation of a K-shaped node under axial force (one end in tension and one end in compression).

[0031] Figure 6 Figure 6 is a comparison of bearing capacity of a K-shaped eccentric node and a T-shaped eccentric node. DETAILED DESCRIPTION

[0032] The application will be further described below with reference to the accompanying drawings.

[0033] REFERENCE Figures 1-6 A construction method of an assembled steel pipe truss elevator shaft structure, comprising the following steps:

[0034] In step S1, according to the bearing capacity and stiffness requirements of the existing house structure and the elevator shaft structure to be added, the cross-sectional height and width h0×b0, h1×b1 of the chord and web of the steel pipe truss are determined, the chord is a main pipe, and the web is a branch pipe, the steel pipe truss adopts a K-shaped eccentric gap type intersecting node of the branch pipe and the main pipe on one flat side, so that the outer surface of the elevator shaft structure to be added is flat and convenient for laying the wall surface, and the included angle θ of the branch pipe and the main pipe in the K-shaped node is set to 45°. i The ratio β of the cross-sectional width of the branch pipe to the main pipe is 0.6, and the wall thickness t0 and t1 of the main pipe and the branch pipe is 6-8 mm. The outer corner of the main pipe and the branch pipe has the same inner diameter r1 and wall thickness, and the outer diameter r2 is twice the r1. The two branch pipes adopt a gap type and have an eccentric intersecting node with the main pipe on one flat side. The axial force transmitted by the two branch pipes should be less than the bearing capacity of the eccentric intersecting node. Since there is no formula for calculating 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 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) (i.e. the relevant provisions in item 13.4.2-2), and the minimum value of the three formulas is taken,

[0035]

[0036] In the formula, θ iis the included angle between the branch pipe and the main pipe, β is the ratio of the branch pipe to the main pipe section height, b is the main pipe section width, t is the main pipe section wall thickness, f is the branch pipe strength design value, ψ n is calculated according to the above formula when the main pipe is under pressure, and is 1.0 when it is under tension, 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 is the shear strength design value of the main pipe steel; b i , h i , t i are the section width, height and wall thickness of the i-th branch pipe, respectively, b ei is the effective section width of the i-th branch pipe, f i is the tensile (compressive and bending) strength design value of the branch pipe steel.

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

[0038] Step S2, the main pipe and the branch pipe are welded in the factory, and the welding is carried out by using fillet weld, 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] In the formula, N i is the axial force design value of the branch pipe; h e is the calculated thickness of the fillet weld, when the branch pipe bears 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 the gap type K-shaped node and θ i ≤50°,

[0042]

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

[0044] Step S3, select the appropriate size of the bolt end plate and the I-beam: first, according to the overall structure calculation results and the construction requirements to 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 flange w, tf, and welding the I-beam with 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 Steel Structure Design Standard (GB50017-2017), the bolt end plate adopts an overhanging end plate, the thickness of the bolt end plate is not less than the diameter of the bolt, and the thickness of the bolt and the diameter of the bolt end plate are calculated; the single-side bolt is calculated according to the strength of the bolt, the thickness of the bolt end plate is kept consistent with the thickness of the main pipe, which is 6 to 8 mm, and the diameter of the single-side bolt is 6 to 8 mm.

[0045] Step S4, according to the overall structure design of the house, the overall structure of each truss is constructed, and the truss, the I-beam with the end plate, and the single-side bolt are transported to the construction site, ready for the next step of construction.

[0046] Step S5, the single-side bolt connects two steel trusses and I-beams to form a whole elevator shaft structure, one direction of the elevator shaft structure is a steel pipe truss structure, which is perpendicular to the truss, and the other direction is a steel pipe column-I-beam frame structure, the main pipe in the truss serves as a steel pipe column, and the design and construction of the overall space elevator shaft structure are completed.

[0047] The advantages of the present application compared with the general T-shaped node elevator shaft frame structure commonly used at present are: ① K-shaped eccentric rectangular steel pipe intersecting nodes are used instead of conventional T-shaped central rectangular steel pipe intersecting nodes, which greatly improves the bearing capacity of the nodes and facilitates the construction of the outer wall surface. ② The space structure constructed in the factory is simplified to a plane structure, improving the transportation efficiency. ③ The I-beam with the end plate and the single-side bolt are used to connect each frame, effectively solving the problem of closed cross-section bolt connection. ④ The bearing capacity and lateral stiffness of the overall structure are improved, and the welding quality and construction efficiency are improved.

[0048] The content described in the embodiments of the present specification is only a list of implementation forms of the inventive concept, and is only for the purpose of description. The protection scope of the present application should not be regarded as being limited to the specific forms described in the embodiments, and the protection scope of the present application also extends to equivalent technical means that can be thought of by those skilled in the art according to the inventive concept.

Claims

1. A construction method of a fabricated steel pipe truss elevator shaft structure, characterized by, The method comprises the following steps: Step S1, according to the height of the existing building, and the bearing capacity and stiffness requirement factors of the installed elevator shaft structure to determine the section height x width h0x b0, h1x b1 of the chord and web of the steel pipe truss, the chord is the main pipe, the web is the branch pipe, the steel pipe truss adopts the K-shaped eccentric gap type intersecting node with the branch pipe and the main pipe in one plane, and the included angle of the branch pipe and the main pipe in the K-shaped node is , the ratio of the section width of the branch pipe and the main pipe β , the wall thickness of the main pipe and the branch pipe is t0 and t1; Step S2, welding the main pipe and the branch pipe in the factory, welding by using the fillet weld, setting the length, thickness and strength design value of the weld; Step S3, selecting a bolt end plate and an I-beam with appropriate sizes; Step S4, designing and constructing each truss structure according to the existing structure of the house and the available outdoor space, and transporting the truss, the I-beam with the end plate at both ends and the single-side bolt to the construction site, and preparing for the next construction; Step S5, connecting the two steel pipe trusses and the I-beam by using the single-side bolt, so as to form an integrated elevator shaft structure, one direction of the integrated elevator shaft structure is the steel pipe truss structure, and the vertical direction of the truss is the steel pipe column-I-beam frame structure, the main pipe in the truss serves as the steel pipe column, and the design and construction of the integrated space elevator shaft structure are completed; In the step S1, the included angle between the branch pipe and the main pipe in the K-shaped node is 45°, the ratio β of the cross-sectional width of the branch pipe to the main pipe is 0.6, the wall thickness t0 and t1 of the main pipe and the branch pipe is 6-8mm; the outer corner of the main pipe and the branch pipe has the same inner diameter r1 and wall thickness, and the outer diameter r2 is twice the r1; the two branch pipes of the K-shaped node adopt the gap type setting, and the connection form of the eccentric intersecting node with the branch pipe and the main pipe flush on one side; the axial force transmitted by the two branch pipes is less than the bearing capacity of the eccentric intersecting node, the bearing capacity of the K-shaped steel pipe eccentric intersecting node is calculated according to the following formula, and the minimum value of the three formulas is taken, ； ； ； ； wherein, is the included angle between the branch pipe and the main pipe, is the ratio of the height of the cross section of the branch pipe to the main pipe, is the cross-sectional width of the main pipe, is the cross-sectional wall thickness of the main pipe, is the strength design value of the branch pipe, is calculated according to the above formula when the main pipe is under pressure, and is 1.0 when it is under tension, is the larger absolute value of the axial compressive stress of the main pipe on both sides of the joint, is the shear area of the main pipe, is the shear strength design value of the main pipe steel; , , are the cross-sectional width, height and wall thickness of the i-th branch pipe, respectively, is the effective cross-sectional width of the i-th branch pipe, is the tensile strength design value of the branch pipe steel.

2. The construction method of a fabricated steel pipe truss elevator shaft structure according to claim 1, wherein The main pipe is a rectangular main pipe, and the branch pipe is a rectangular branch pipe.

3. The construction method of a fabricated steel pipe truss elevator shaft structure according to claim 1, wherein In the step S2, the length, thickness and strength design value of the weld are as follows: ； wherein is the design value for the axial force of the branch pipe; is the calculated thickness for the fillet weld, and the average calculated thickness is taken as 0.7 , is the weld size; is the calculated length of the weld; is the design value for the strength of the fillet weld; for gap-type K-joints and when, ； wherein is the included angle of the branch pipe and the main pipe, , are the cross-sectional width and height of the i-th branch pipe, respectively.

4. The construction method of a fabricated steel pipe truss elevator shaft structure according to claim 1, wherein In the step S3, the height H of the I-beam, the flange width B, and the thickness t of the web and the flange are determined according to the overall structure calculation result and the construction requirement w , t f The I-beam and the bolt end plate are welded in the factory; the bolt end plate is an overhanging end plate, the thickness of the bolt end plate is not less than the diameter of the bolt, and the thickness of the bolt and the diameter of the bolt end plate are calculated; the single-side bolt is calculated according to the strength of the bolt, the thickness of the bolt end plate is kept consistent with the thickness of the main pipe, and is 6-8 mm, and the diameter of the single-side bolt is 6-8 mm.

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