Stud fixing joint of high-thrust directly-buried laying pipe network

Abstract

The utility model discloses a high-thrust direct burial laying pipe network stud fixing joint, the stud fixing joint is fixedly connected in a fixing pier in a pouring way, the stud fixing joint comprises an outer sleeve steel pipe and a compaction reinforcing steel bar, the outer sleeve steel pipe is fixedly sleeved on the circumferential outer wall of a working steel pipe at intervals, and the compaction reinforcing steel bar is fixedly sleeved on the outer wall of the working steel pipe. The interval between the outer sleeve steel pipe and the working steel pipe is filled with a heat preservation layer, and a plurality of stud rings are axially distributed on the periphery of the outer sleeve steel pipe at intervals. The stud rings are clamped by compaction steel bars in the axial direction of the working steel pipe, and the compaction steel bars are fixedly arranged on the reinforcing bars of the fixing pier in a welded mode. According to the stud fixing joint, the shear-resistant studs are additionally arranged on the outer side of the outer sleeve steel pipe so as to resist longitudinal shear force between concrete and profile steel, the connecting strength of the steel pipe and the concrete can be greatly enhanced, and the overall stress performance of the fixing pier is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of pipeline construction, in particular to a bolt fixing joint for directly burying a pipeline network with large thrust. Background Art

[0002] In the field of district heating pipe networks, pipe networks are generally laid directly buried. In direct buried heating pipe networks, fixed piers are frequently used accessories. As the core pipe fittings of fixed piers, the design of fixed joints plays a very critical role in municipal structures. The traditional fixed joints commonly used now are to directly weld the side ear baffles on the outside of the working steel pipe and fix them in the concrete to form fixed piers.

[0003] The defects and shortcomings of the prior art are that the above-mentioned traditional fixed node structure not only causes direct heat conduction of the baffle plate, reducing the life of the outer concrete, but also makes the stress distribution around the baffle plate uneven.

[0004] In view of the above situation, the patented bolt fixing section, which is named as a bolt fixing section used in high-thrust direct buried pipe network, has improved the conventional fixed pier. The bolt fixing section of this patent has added shear bolts on the outside to resist the longitudinal shear force between concrete and steel, which can greatly strengthen the connection strength between steel pipe and concrete and improve the overall force performance of the fixed pier. The bolt fixing section is used to achieve ideal results in high-thrust direct buried pipe network. Utility Model Content

[0005] The purpose of the utility model is to solve the deficiencies of the prior art and to propose a bolt fixing joint for direct buried pipe network with large thrust, in which shear-resistant bolts are added to the outside of the outer sleeve steel pipe to resist the longitudinal shear force between concrete and steel sections, which can greatly strengthen the connection strength between the steel pipe and concrete and improve the overall force-bearing performance of the fixed pier.

[0006] A bolt fixing section for laying a large-thrust direct-buried pipe network, the bolt fixing section is cast and fixedly connected inside a fixed pier, the bolt fixing section comprises an outer sleeve steel pipe and compacted steel bars, wherein the outer sleeve steel pipe is fixed and sleeved on the circumferential outer wall of a working steel pipe at intervals, the interval between the outer sleeve steel pipe and the working steel pipe is filled with a thermal insulation layer, and a plurality of bolt rings are arranged at axial intervals on the outer periphery of the outer sleeve steel pipe; the bolt rings are clamped along the axial direction of the working steel pipe by compacted steel bars, and the compacted steel bars are welded and fixed on the reinforcement of the fixed pier.

[0007] Preferably, a plurality of stiffening plates fixedly connected to the outer wall of the working steel pipe are fixedly arranged at intervals on the arcuate inner wall of the outer sleeve steel pipe.

[0008] Preferably, the bolt ring includes a plurality of bolts which are evenly distributed circumferentially and radially extended and fixed on the outer wall of the curved surface of the outer sleeve steel pipe. The bolts are clamped along the axial direction of the working steel pipe by compacted steel bars cast in the fixed pier.

[0009] Preferably, the insulation layer is attached to the arc-surface inner wall of the outer sleeve steel pipe, the arc-surface outer wall of the working steel pipe and the side wall of the stiffening plate.

[0010] The advantages and technical effects of the utility model are:

[0011] The utility model discloses a bolt fixing section for laying pipe network with large thrust directly buried. The bolt fixing section structure has shear-resistant bolts added to the outside, and the force transmission is clear. The structure is simple, and the finished product can be produced in the factory, and the quality is stable and reliable. In addition, the bolt fixing section structure fills the insulation material between the working steel pipe and the outer sleeve steel, which solves the insulation problem of the fixing section, achieves a good insulation effect, reduces heat loss, reduces heat consumption, and increases the service life of the fixing pier, providing a reliable guarantee for the normal operation of large-diameter and large-thrust heating pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a cross-sectional view (side view) of the utility model;

[0013] Figure 2 It is a cross-sectional view of the utility model (axis end perspective);

[0014] Figure 3 It is a schematic diagram of the steel bar compaction connection of the bolt fixing section in the utility model inside the fixed pier;

[0015] In the figure: 1-working steel pipe; 2-outer steel pipe; 3-fixed pier; 4-bolt; 5-compacted steel bar; 6-insulation layer; 7-stiffening plate. DETAILED DESCRIPTION

[0016] The embodiments of the utility model are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the utility model, and cannot be understood as limiting the utility model.

[0017] A bolt fixing section for high-thrust direct-buried pipe network, the bolt fixing section is cast and fixed inside a fixed pier 3, the bolt fixing section comprises an outer sleeve steel pipe 2 and extruded steel bars 5, wherein the outer sleeve steel pipe is fixed and sleeved on the circumferential outer wall of a working steel pipe 1 at intervals, the interval between the outer sleeve steel pipe and the working steel pipe is filled with an insulation layer 6, and a plurality of bolt rings are arranged at axial intervals on the outer periphery of the outer sleeve steel pipe; the bolt rings are clamped along the axial direction of the working steel pipe by extruded steel bars, and the extruded steel bars are welded and fixed on the reinforcement of the fixed pier.

[0018] Preferably, a plurality of stiffening plates 7 fixedly connected to the outer wall of the working steel pipe are fixedly arranged at intervals on the arcuate inner wall of the outer sleeve steel pipe.

[0019] Preferably, the bolt ring includes a plurality of bolts 4 which are evenly distributed circumferentially and radially extended and fixed on the outer wall of the outer casing steel pipe. The bolts are clamped along the axial direction of the working steel pipe by the compacted steel bars cast in the fixed pier.

[0020] Preferably, the insulation layer is attached to the arc-surface inner wall of the outer sleeve steel pipe, the arc-surface outer wall of the working steel pipe and the side wall of the stiffening plate.

[0021] In order to more clearly illustrate the specific implementation of the utility model, an embodiment is provided below:

[0022] 1. The utility model is a bolt fixing joint for direct buried pipe network with large thrust, and its design principle is as follows:

[0023] This stud-fixed joint form draws on the requirements for the composite structure of steel-concrete beams and steel-concrete columns in the "Technical Code for Concrete Structures of High-rise Buildings". In order to ensure the common deformation of concrete and steel, shear studs are added to the outside of the steel embedded in the concrete to resist the longitudinal shear force between the concrete and the steel.

[0024] The bolt fixing joint adopts the form of working steel pipe + stiffening plate + outer steel pipe + bolt. The working steel pipe and the outer steel pipe are filled with insulation material to prevent the heat in the pipeline from being directly transferred to the concrete through the fixing joint. The bolt fixing joint forms an integral fixing joint, which can be processed as a finished product in the factory.

[0025] The thrust transmission path of the pipeline with bolted fixed joints is: working steel pipe → stiffening plate → outer steel pipe → bolt → reinforced concrete fixed pier. The bolted fixed joint adopts the form of steel-in-steel, which not only solves the direct heat conduction of the traditional fixed joint baffle and increases the durability of the outer concrete, but also makes the extruded distribution steel bars around the baffle better arranged, the stress diffusion is uniform, and the fixing effect of the fixed pier in the pipe network is more solid.

[0026] 2. The material selection and experimental verification of the bolt fixing joint for a large thrust direct buried pipe network of the utility model are as follows:

[0027] 2.1 Mechanical properties of studs

[0028] The mechanical properties of studs usually include tensile strength, yield strength and elongation, see Table 1.

[0029] Table 1 Model, specification, selected materials and mechanical properties of bolt products

[0030]

[0031] 2.2 Stud size

[0032] The sizes of bolts usually have the following specifications, see Table 2.

[0033] Table 2 Bolt size table

[0034]

[0035] Note: WA is the melting length of cylindrical head welding studs.

[0036] 2.3 Material selection and specifications of outer jacket steel and stiffening plates

[0037] For welding reliability, the outer jacket steel and stiffening plate are made of the same material as the working steel pipe. To facilitate the connection between the two ends of the bolt fixing joint and the insulation steel pipe, the outer diameter of the outer jacket steel pipe is the same as the outer diameter of the insulation shell of the heating pipe.

[0038] 3. Design of bolt bearing capacity and calculation of bolt quantity

[0039] The number of studs on each fixed node requires the shear bearing capacity of a single stud to be calculated first.

[0040] 3.1 Calculation of shear capacity of a single stud:

[0041] Concrete compression control:

[0042] Single stud shear capacity control: N v ≤0.7A S f u (2)

[0043] Note: For safety, take the smaller value of (1) and (2).

[0044] As——Cross-sectional area of ​​bolt rod (mm 2 );

[0045] Fu is the design value of the ultimate tensile strength of the stud;

[0046] Ec——elastic modulus of concrete (N / mm 2 );

[0047] fc——design value of concrete axial compressive strength (N / mm 2 );

[0048] k——empirical coefficient, commonly used k=0.43.

[0049] Table 3 Cross-sectional area of ​​commonly used bolt rods (mm 2 )

[0050] Nominal diameter of stud d 10 13 16 19 22 25 Cross-sectional area Ad of the bolt rod 78.5 132.67 200.96 283.39 379.94 490.63

[0051] Table 4 Elastic modulus of commonly used concrete (×10 4 N / mm 2 )

[0052]

[0053] Table 5 Commonly used concrete axial compressive strength design values ​​(N / mm 2 )

[0054]

[0055] 3.2 Calculation of the number of shear studs

[0056] The number of shear studs is calculated as follows:

[0057]

[0058] N l —Longitudinal design value of the contact surface between the outer jacket steel pipe and concrete, i.e., the design value of pipeline thrust (kN);

[0059] N v —Shear capacity of a single stud (kN).

[0060] 4 Construction requirements

[0061] The bolt-fixed joint must meet the following structural requirements:

[0062] (1) The stiffening plates are evenly arranged at 30 degrees in the circumferential direction, butt-welded to the working steel pipe on the inside, and bevel-welded to the steel casing on the outside. The wall thickness of the steel casing is as close as possible to that of the working steel pipe to ensure that the stiffness of the inner and outer steel pipes is as coordinated as possible.

[0063] (2) The spacing of bolts along the force direction of the pipeline: 6d≤the spacing of bolts≤200mm;

[0064] (3) Circumferential spacing of bolts vertical to the pipe: The bolts should be evenly arranged in a circular pattern on the outside of the outer steel pipe; 4d≤The spacing of the bolts≤200mm; (4) Bolt diameter and length: The bolt diameter is usually 10-25mm. Length: The bolt rod length should meet the structural dimensions of two parallel compacted steel bars as much as possible within the bolt rod length range, so it is recommended that the bolt rod length be ≥200mm.

[0065] (5) To avoid local stress concentration at the contact surface between the stud and concrete, compacted steel bars are arranged on the front and rear sides of the stud. The compacted steel bars are arranged in an octagonal shape around the stud. Figure 3 .

[0066] 5 Requirements for welding of bolt-fixed joints

[0067] The material model of the stud is generally ML15 or ML15AL. The studs should comply with the requirements of GB / T10433-2002 "Cylindrical Head Studs for Arc Stud Welding". The studs are in the form of ceramic rings, and ordinary flat welding ceramic rings are selected. The size of the ceramic rings matches the size of the studs.

[0068] Before construction, the construction unit should have quality certificates such as quality inspection sheets issued by the bolt manufacturer, and lay out the bolt construction position lines (points) according to the spacing, row spacing and position requirements specified on the engineering construction design drawings.

[0069] Stud welding uses a special stud welder equipped with a stud welding gun.

[0070] 6. Stud Inspection

[0071] The studs need to be inspected in the following aspects:

[0072] (1) Appearance inspection

[0073] Check whether the studs are vertical and the weld is uniform, whether the weld is full and uniform, and whether there is any biased welding. If the weld layer is fully melted and uniform, it is qualified.

[0074] (2) Tensile test

[0075] When the tensile load reaches the minimum value of the tensile load in Table 6, there shall be no rupture; continue to increase the load until it breaks, and the rupture shall not occur in the weld and heat affected zone.

[0076] Table 6 Minimum tensile load of a single bolt

[0077] Nominal diameter of stud(mm) 10 13 16 19 22 25 Tensile load(kN) 32.970 55.860 84.420 119.280 159.600 206.220

[0078] (3) Bending test

[0079] The bending test is mainly carried out by hammering inspection. For bolts with defects in appearance, they are bent 30° by hammering in the opposite direction of the defective part. If there is no cracking in the weld and heat-affected zone and no abnormality in the weld, it can be judged as qualified. If cracks appear in the weld, it is regarded as scrapped. If it fails, a bolt needs to be welded slightly off the original position to supplement it. The bent bolt does not need to be straightened.

[0080] (4) Acceptance criteria

[0081] Acceptance of studs shall meet the criteria in Table 7.

[0082] Table 7 Sampling inspection standards

[0083]

[0084]

[0085] Note: Ac is the qualified number, Re is the unqualified number.

[0086] (5) Stud shear performance test

[0087] Stud shear test method: adopt the push-out test method along the pipeline axis, and observe the bearing capacity of the connector under static load through the push-out test of the connector.

[0088] Finally, all the unexplained parts of the utility model adopt mature products and mature technical means in the existing technology.

[0089] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in the embodiment or example of the utility model.

[0090] Although embodiments of the utility model have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the utility model, and that the scope of the utility model is defined by the claims and their equivalents.

Claims

1. A bolt fixing section for laying a pipe network with large thrust directly buried, the bolt fixing section is cast and fixed inside the fixed pier, characterized in that: The bolt fixing section includes an outer sleeve steel pipe and compacted steel bars, wherein the outer sleeve steel pipe is fixed and sleeved on the circumferential outer wall of the working steel pipe at intervals, the interval between the outer sleeve steel pipe and the working steel pipe is filled with an insulation layer, and a plurality of bolt rings are arranged axially at intervals on the outer periphery of the outer sleeve steel pipe; the bolt rings are clamped along the axial direction of the working steel pipe by compacted steel bars, and the compacted steel bars are welded and fixed on the reinforcement of the fixed pier.

2. The bolt fixing joint for high-thrust direct-buried pipe network according to claim 1 is characterized in that: A plurality of stiffening plates fixedly connected to the outer wall of the working steel pipe are fixedly arranged at intervals on the arc surface inner wall of the outer sleeve steel pipe.

3. The bolt fixing joint for direct buried pipe network with large thrust according to claim 1 is characterized by: The bolt ring includes a plurality of bolts which are evenly distributed circumferentially and radially extended and fixed on the outer wall of the outer sleeve steel pipe. The bolts are clamped along the axial direction of the working steel pipe by the compacted steel bars cast in the fixed pier.

4. The bolt fixing joint for high-thrust direct-buried pipe network according to claim 2 is characterized in that: The heat-insulating layer is attached to the arc-surface inner wall of the outer sleeve steel pipe, the arc-surface outer wall of the working steel pipe and the side wall of the stiffening plate.

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