Node of large-span prefabricated truss and prefabricated column, which is firstly hinged and then rigid

Abstract

The utility model relates to the technical field of constructional engineering, and discloses a first-hinging and second-rigid joint of a large-span prefabricated truss and a prefabricated column. The first-hinging and second-rigid joint of the large-span prefabricated truss and the prefabricated column comprises the prefabricated column, a connecting plate, the prefabricated truss, a temporary bracket, a friction sliding pad and a steel frame beam, the temporary bracket is located below the prefabricated truss, the temporary bracket supports the bottom of a joint of the prefabricated truss through the friction sliding pad, the side of the joint of the prefabricated truss is connected with one end of the connecting plate through a bolt, and the other end of the connecting plate is connected with the side of the prefabricated column through a bolt. Node stress under the action of self weight can be greatly reduced, bending moment and horizontal tension transmitted to the supporting column are reduced, and therefore the section of a component is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of building engineering especially, a first hinge later rigid node of large -span prefabricated truss and prefabricated column. BACKGROUND

[0002] Large -span steel truss structure is often used in bridge, gymnasium, terminal building etc. building, in the process of erecting this steel structure, a large number of nodes will appear, and the connecting node between support column and steel truss needs to be paid attention to, on the one hand, the connecting node at this place directly determines the stability of the whole large -span steel truss structure, and its design must be able to effectively transfer and distribute load to prevent the structure from being unstable or collapsing under external load. On the other hand, the connecting node is the key interface between the support column and the steel truss, responsible for transferring various stresses, including vertical and horizontal loads. A well-designed node can effectively transfer these stresses to ensure that all parts of the structure can bear appropriate loads and avoid excessive local stress, thereby improving the overall structural performance.

[0003] At present, the most widely used node connection technology is rigid connection and hinge connection, the former such as welding or bolt connection, convenient construction, relatively low cost, the latter such as pin shaft and spherical hinge, relatively high cost. For large -span steel truss structure, the dead weight is its main load, if the construction process of steel truss and support column adopts rigid connection, then the deformation under the action of dead weight is constrained by the surrounding support column, and a large stress is generated at the node, which can lead to excessive thickness of the node steel plate. At the same time, this stress is transferred to the support column, causing large bending deformation of the support column. For columns with small cross section, the stress is very poor, which is easy to yield, resulting in the need to increase the column cross section. The increased column cross section further constrains the deformation of the truss due to its large stiffness, resulting in larger stress in the node area, which may enter a vicious cycle, resulting in a large waste of component cross section. Therefore, it is necessary to release the stress of the truss and the dead weight of the floor system in the node area, set the node to a hinge state at the beginning, and then restore the rigid state to bear the live load and horizontal load, etc. to increase the redundancy of wind resistance, earthquake resistance and accidental action. UTILITY MODEL CONTENTS

[0004] The utility model aims at overcoming the defects of the prior art, and provides a first hinge later rigid node of large -span prefabricated truss and prefabricated column.

[0005] The utility model discloses a construction method for a first hinge later rigid node of large -span prefabricated truss and prefabricated column, which is characterized by comprising the following steps:

[0006] S1, first, the prefabricated column and the prefabricated truss are respectively welded to form, then the prefabricated column is hoisted and fixed, the steel frame beam and the temporary bracket are welded on the prefabricated column, the temporary bracket is located below the steel frame beam, the friction sliding pad is arranged on the top of the temporary bracket, then the prefabricated truss is hoisted, the bottom of the node of the prefabricated truss is placed on the friction sliding pad, the upper side of the node of the prefabricated truss is connected with one end of the connecting plate, the other end of the connecting plate is connected with the side of the prefabricated column through bolts;

[0007] S2, after the prefabricated column and the prefabricated truss are in the preset stress and deformation stability, the chord and the web of the prefabricated truss are sequentially welded from bottom to top with the column node plate of the prefabricated column, in order to realize welding, part of the web and the flange are respectively arranged as the rear-welded web and the rear-welded flange.

[0008] More preferably, after step S2 is completed, the temporary bracket is removed.

[0009] A prefabricated truss and prefabricated column first-hinged and then-rigid node comprises a prefabricated column, a connecting plate, a prefabricated truss, a temporary bracket, a friction sliding pad and a steel frame beam, the steel frame beam and the temporary bracket are welded with the prefabricated column, the temporary bracket is located below the prefabricated truss, the temporary bracket supports the node bottom of the prefabricated truss through the friction sliding pad, the side of the node of the prefabricated truss is connected with one end of the connecting plate through bolts, and the other end of the connecting plate is connected with the side of the prefabricated column through bolts.

[0010] More preferably, the prefabricated truss comprises a web, a chord and a truss node plate, the chord is connected with the web through the truss node plate, the bottom of the truss node is placed on the top of the friction sliding pad, and the side of the truss node plate is connected with one end of the connecting plate through bolts.

[0011] More preferably, the prefabricated truss further comprises a rear-welded web and a rear-welded flange plate, the two sides of the rear-welded web are welded to the prefabricated column, and the two sides of the rear-welded flange plate are welded to the truss node plate of the prefabricated truss.

[0012] More preferably, the structure of the web comprises an I-shaped or box-shaped structure.

[0013] More preferably, the structure of the chord comprises an I-shaped or box-shaped structure.

[0014] More preferably, the prefabricated column comprises a support column and a column node plate, the support column is welded with one end of the column node plate, and the other end of the column node plate is connected with the connecting plate through bolts.

[0015] More preferably, the support column comprises a steel column or a steel pipe concrete column.

[0016] The utility model has the following advantages and beneficial effects compared with prior art:

[0017] Compared with the prior art, the utility model adopts the mode of first hinging and then rigidly connecting, can greatly reduce the node stress under the dead weight, reduce the bending moment and horizontal tension force transmitted to the supporting column, thereby reducing the component section, is economical and practical, realizes the stress requirement in the later period, makes the structure safer and more reliable. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic view of a first-hinge-then-rigid node (located at the lower support) of a large-span prefabricated truss and prefabricated column of the utility model;

[0019] Figure 2 is a schematic view of a first-hinge-then-rigid node (located at the upper support) of a large-span prefabricated truss and prefabricated column of the utility model;

[0020] Figure 3 is a schematic view of a first-hinge-then-rigid node of a large-span prefabricated truss and prefabricated column of the utility model;

[0021] Figure 4 is a schematic view of a first-hinge-then-rigid node of a large-span prefabricated truss and prefabricated column of the utility model;

[0022] Figure 5 is a schematic view of a first-hinge-then-rigid node of a large-span prefabricated truss and prefabricated column of the utility model;

[0023] Figure 6 is a schematic view of a mechanical model of a first-hinge-then-rigid node of a large-span prefabricated truss and prefabricated column of the utility model under the action of dead load (a is the node on the lower support, b is the node on the upper support);

[0024] Figure 7 is a schematic view of the axial displacement of a first-hinge-then-rigid node of a large-span prefabricated truss and prefabricated column of the utility model along the chord under the action of dead load (a is the node on the lower support, b is the node on the upper support, unit: mm);

[0025] Figure 8 is a schematic view of a three-dimensional finite element model of a first-hinge-then-rigid node of a large-span prefabricated truss and prefabricated column of the utility model (a is the first-hinged state, b is the second-rigidly connected state, and c is the second-rigidly connected state and the temporary corbel is cut off);

[0026] Figure 9 is a schematic view of the Mises stress of steel (unit: MPa) of a first-hinge-then-rigid node of a large-span prefabricated truss and prefabricated column of the utility model under the action of dead load and the first-hinged state;

[0027] Figure 10is a schematic diagram of the Mises stress (unit: MPa) of steel under the combined action of the middle earthquake and the post rigid connection state of the precast truss and the precast column with the first hinge and the post rigid joint;

[0028] Figure 11 is a schematic diagram of the Mises stress (unit: MPa) of steel under the combined action of the large earthquake and the post rigid connection state of the precast truss and the precast column with the first hinge and the post rigid joint;

[0029] Figure 12 is a schematic diagram of the Mises stress (unit: MPa) of steel under the combined action of the middle earthquake and the post rigid connection state of the precast truss and the precast column with the first hinge and the post rigid joint (cutting off the temporary corbel);

[0030] Figure 13 is a schematic diagram of the main compression stress of the inner concrete of the support column under the combined action of the constant load and the post rigid connection state of the precast truss and the precast column with the first hinge and the post rigid joint;

[0031] Figure 14 is a schematic diagram of the main compression stress of the inner concrete of the support column under the combined action of the middle earthquake and the post rigid connection state of the precast truss and the precast column with the first hinge and the post rigid joint;

[0032] Figure 15 is a schematic diagram of the main compression stress of the inner concrete of the support column under the combined action of the large earthquake and the post rigid connection state of the precast truss and the precast column with the first hinge and the post rigid joint;

[0033] Figure 16 is a schematic diagram of the main compression stress of the inner concrete of the support column under the combined action of the middle earthquake and the post rigid connection state of the precast truss and the precast column with the first hinge and the post rigid joint;

[0034] Markings of components in the drawings: 1-support column; 101-inner ring plate; 2-web; 3-chord; 4-connection plate; 401-long round screw hole; 5-column joint plate; 6-truss joint plate; 7-temporary corbel; 8-friction sliding pad; 9-post-weld web plate; 10-post-weld flange plate; 11-steel frame beam; 12-bolt; 13-joint; 14-core tube; 15-joint area. DETAILED DESCRIPTION

[0035] The utility model discloses a utility model purposes further detailed description below combining with the drawings and specific embodiment, and the embodiment cannot be elaborated here one by one, and the utility model implementation mode is not therefore limited to the following embodiment.

[0036] As Figures 1-4As shown, a large-span prefabricated truss and prefabricated column hinge first rigid node includes a prefabricated column, a connecting plate 4, a prefabricated truss, a temporary corbel 7, a friction sliding pad 8, a steel frame beam 11, a post-weld flange plate 10 and a post-weld web plate 9. The prefabricated truss is welded by web members 2, chord members 3 and truss node plates 6. The prefabricated column includes a support column 1 and a column node plate 5, and the support column 1 is provided with an inner ring plate 101 for enhancing the stress of the support column 1. The steel frame beam 11 is welded with the support column 1, the temporary corbel 7 is welded with the support column 1, and the temporary corbel 7 is located directly below the truss node plate 6 of the prefabricated truss. The friction sliding pad 8 is arranged on the top of the temporary corbel 7. The chord member 3 is placed on the friction sliding pad 8, and the axial direction of the chord member 3 is the same as that of the steel frame beam 11. The chord member 3 is welded with the truss node plate 6, and the top of the truss node plate 6 is welded with the web member 2. The top of the truss node plate 6 is welded with the post-weld flange plate 10, and the post-weld flange plate 10 is located on the left side of the web member 2. The truss node plate 6 is connected with one end of the connecting plate 4 through a bolt 12, the other end of the connecting plate 4 is connected with one end of the column node plate 5 through the bolt 12, and the other end of the column node plate 5 is connected with the support column 1. The post-weld web plate 9 is welded on the flange of the member of the column node plate 5 of the prefabricated column and is located between the connecting plate 4 and the temporary corbel 7. The post-weld web plate 9 and the post-weld flange plate 10 are arranged as needed, and when the members of the prefabricated truss are I-shaped members, the post-weld web plate 9 and the post-weld flange plate 10 can not be arranged.

[0037] The support column 1 is a steel column or a steel pipe concrete column, which plays a supporting role. The bolt 12 is used to connect the prefabricated truss and the support column 1 through the connecting plate 4. The connecting plate 4 is provided with a long circular screw hole 401 for connecting the prefabricated truss and the support column 1, which not only meets the requirement of transmitting shear force, but also meets the requirement of realizing the hinge connection of the node along the small transverse displacement, and ensures the safety of the connection between the steel support column 1 and the web member 2. The prefabricated truss plays a supporting and bearing role. The temporary corbel 7 realizes the force transmission requirement of the prefabricated truss. The friction sliding pad 8 is a low-friction sliding pad 8 (a kind of gasket with extremely low friction coefficient, usually used to reduce friction and wear between moving parts), which not only meets the requirement of transmitting the pressure of the prefabricated truss, but also meets the requirement of realizing the hinge connection of the node along the small transverse displacement, and ensures the safety of the connection between the temporary corbel 7 and the chord member 3. The steel frame beam 11 plays a bearing role. The post-weld flange plate 10 is used to increase the stress intensity of the truss node plate 6. The structure of the web member 2 is I-shaped or box-shaped, which generates friction resistance with the low-friction sliding pad 8. The structure of the chord member 3 is I-shaped or box-shaped, which plays a supporting and connecting role. The truss node plate 6 is used to connect the web member 2 and the chord member 3, and is used to connect the support column 1; the column node plate 5 is used to connect the prefabricated truss, and plays a stress role. The post-weld web plate 9 is used to enhance the stress intensity of the support column 1.

[0038] A construction method of a large-span prefabricated truss and a prefabricated column first-hinged and then-rigid node comprises the following steps:

[0039] In step S1, the column node plate 5 is welded to the support column 1 in a factory to obtain a prefabricated column; then the web member 2, the chord member 3 and the truss node plate 6 are welded in the factory to obtain a prefabricated truss. Then the prefabricated column and the prefabricated truss are transported to the site. First, the prefabricated column is hoisted and fixed, the steel frame beam 11 and the temporary corbel 7 are welded to the support column 1 of the prefabricated column, and the temporary corbel 7 is located below the steel frame beam 11. The low-friction sliding pad 8 is placed on the temporary corbel 7. Then the prefabricated truss is hoisted as a whole, and the node bottom of the prefabricated truss is placed on the low-friction sliding pad 8. The upper side of the node of the prefabricated truss is connected with one end of the connecting plate 4, and the connecting plate 4 is connected with the column node plate 5 through the bolt 12, thereby completing the hinging between the prefabricated truss and the prefabricated column.

[0040] In step S2, after the prefabricated column and the prefabricated truss are pre-set to be stable in stress and deformation, the prefabricated truss is pre-set to be stable in stress and deformation, the upper and lower flanges and the web plate of the web member 2 and the chord member 3 at the node are one-to-one corresponding to the column node plate 5, and are welded from bottom to top. Then the post-welding web plate 9 is welded on the column node plate 5 of the prefabricated column, and then the connecting plate 4 and the bolt 12 are removed. The post-welding flange plate 10 is welded on the top of the truss node plate 6 of the prefabricated truss, and in order to realize the feasibility of welding, the welding of the prefabricated truss and the prefabricated column is completed. The temporary corbel 7 can not be removed when it does not affect the main body.

[0041] The stress analysis of the node of the embodiment is as follows:

[0042] As shown in Figure 5 In order to reduce the horizontal force of the chord member 3 transmitted to the core tube 14 under the dead load condition, the construction method of the node in the embodiment adopts the construction measure of "first hinged and then rigid", that is, the chord member 3 of the prefabricated truss can slide along the axial direction within a limited range on the temporary corbel 7 of the support column 1 in the construction stage, so that the axial force of the chord member 3 under the dead load is not transmitted to the core tube 14, and the node bending moment transmitted to the support column 1 by the prefabricated truss is reduced. After the pouring of the connected floor slab is completed and most of the dead load is basically added, the chord member 3 is rigidly connected with the tower column. When the prefabricated truss mainly bears the live load and the horizontal load in the later stage, the chord member 3 can not only transmit the shear force and the axial force, but also transmit the bending moment at the connection position with the tower column.

[0043] The "hinge first and rigid later" of the node in the embodiment is realized by the support node of the upper and lower chords of the prefabricated truss and the tower column. After the prefabricated truss is hoisted, the prefabricated truss is placed on the temporary corbels 7 extended from the support column 1, the contact surface of the two is placed with a friction sliding pad 8, so that the prefabricated truss can slide freely on the temporary corbel 7 within a limited range. To ensure safety during construction, the prefabricated truss is connected with the column node plate 5 of the support column 1 at the same time through high-strength bolts (i.e. bolts 12), and the long round holes of the bolts 12 can meet the deformation needs of the chord 3 sliding. Both the temporary corbel 7 supporting the prefabricated truss and the high-strength bolts can bear the self-weight and construction load of the connected area, ensuring double insurance during construction. After the connected floor is poured, the corresponding steel plates (i.e. the rear welded web plate 9 and the rear welded flange plate 10) are fusion welded, realizing rigid connection.

[0044] 1. Comparison between the direct rigid connection in the prior art and the node in the embodiment:

[0045] As shown in Table 1, the axial forces of the chord 3 of different methods under constant load transmitted to the core tube 14 are compared. As can be seen from the table, the "hinge first and rigid later" structure design of the node can greatly reduce the axial force of the chord 3 transmitted to the core tube 14 under constant load and the design value of the axial force, and greatly reduce the horizontal force of the core tube 14.

[0046] Table 1 Comparison of axial forces of chord of prefabricated truss under constant load transmitted to core tube

[0047]

[0048] 2. Deformation and displacement of the node in the embodiment during the construction stage

[0049] After the prefabricated truss is installed, the prefabricated truss will deform under vertical load during the construction process of the connected floor and the surface layer, and the connected end support will produce displacement and rotation angle. Through fine modeling of the truss support position in the YJK model, as shown in the mechanical model of Figure 6 , the deformation of the truss during the construction process is studied. The deformation result in Figure 7 is obtained. The deformation of the lower support node area 15 relative to the temporary corbel 7 is 9.6 mm, the two are close to each other, and the rotation angle of the node area 15 is 0.03° clockwise; the deformation of the upper support node area 15 relative to the temporary corbel 7 is 4.8 mm, the two are far away from each other, and the rotation angle of the node area 15 is 0.02° clockwise. Figure 1 and Figure 2 The 40mm gap and the long round bolt hole of the node sample can meet the displacement requirements of the support.

[0050] To improve the stress of the prefabricated truss, the connection between the prefabricated truss and the prefabricated column adopts a "hinged first and rigid later" process, that is, when the prefabricated truss is hoisted into position and the connected floor is constructed, the prefabricated truss is supported on the temporary corbel 7 through the sliding friction pad 8, and the temporary corbel 7 bears the shear force of the end of the prefabricated truss in the construction stage; the chord 3 is provided with a horizontal long bolt hole, the low-friction sliding pad 8 is arranged between the temporary corbel 7 and the node connecting plate, the bending moment of the end of the truss in the construction stage is released, and thus the "hinged first" of the prefabricated truss is realized. After the connection is constructed, the side welds of the post-weld flange plate 10 and the truss node plate 6 are supplemented and welded, and the bolts 12 of the long circular hole 401 are tightened, and the end bending moment of the prefabricated truss caused by the horizontal wind and earthquake can be transmitted to the outer frame column of the tower through the chord 3 and the truss node plate 6, so as to realize the "rigid connection later" of the end of the prefabricated truss. In addition, the temporary corbel 7 and the bolt 12 can each bear the vertical force of the end of the prefabricated truss, including the weight of the connection, the surface layer and the partition wall, and the temporary corbel 7 is cut off after the end of the prefabricated truss is rigidly connected. The safety and effectiveness of the node connection are studied through three-dimensional node finite element modeling analysis.

[0051] The component materials and cross-sectional sizes are actually selected according to the design, the end load of the prefabricated column in the hinged first state is only the internal force under the component dead load working condition, and the end load of the prefabricated column in the rigidly connected state is the internal force under the medium earthquake combined envelope and the large earthquake combined envelope respectively. Since the prefabricated truss upper chord flange is post-welded, the end of the chord 3 does not bear the weight of the connection and the construction load, and when the rigidly connected state is simulated, a pair of counter forces (moments) are applied to the nodes at both ends of the end rod to exclude the influence of the dead load.

[0052] As shown in Figures 9-16 The calculation results show that, in the hinged first state, under the action of the dead load and the construction load, the maximum principal compressive stress of the column concrete in the node area is 15.4 MPa, and the maximum Mises stress of the steel in the node area is 155 MPa, both of which do not exceed the design values of the strength of the concrete and the steel; in the rigidly connected state, under the action of the medium earthquake combination, the maximum principal compressive stress of the column concrete in the node area is 20.3 MPa, and the maximum Mises stress of the steel is 313 MPa, both of which do not exceed the design values of the strength of the concrete and the steel. Under the action of the large earthquake combination, the maximum principal compressive stress of the column concrete in the node area is 21.7 MPa, and the maximum Mises stress of the steel is 389 MPa, both of which do not exceed the standard values of the strength of the concrete and the steel. In the rigidly connected state, under the action of the medium earthquake combination, the maximum principal compressive stress of the column concrete in the node area after the corbel is cut off is 23.5 MPa, and the maximum Mises stress of the steel is 313 MPa, both of which do not exceed the design values of the strength of the concrete and the steel.

[0053] After the above analysis, the following conclusions are drawn:

[0054] (1)the temporary corbels 7 can bear the self-weight and construction load of the prefabricated truss in the hinged state, and the truss node plate 6 can bear the vertical force of the end of the prefabricated truss after the temporary corbels 7 are cut off in the rigid state, after the side welds of the post-welded web plate 9, the post-welded truss node plate 6 and the column node plate 5 on the chord are welded and the long round bolt hole 401 is screwed, the construction can cut off the temporary corbels 7;

[0055] (2)the prefabricated truss upper chord node can effectively reduce the axial force of the chord 3 transmitted to the prefabricated column through the "hinged first and rigid later" process;

[0056] (3)the 700mm high hole reserved in the truss node plate 6 can be reserved (for plugging of the post-welded flange plate 10), but it is recommended to post-weld a 20mm thick steel plate, and appropriately increase the stress margin of the truss node plate 6 in the rigid state;

[0057] (4)the node in the embodiment can ensure stress safety in the construction stage and the use stage, and can meet the performance target of medium earthquake elasticity.

[0058] The "hinged first and rigid later" node of the large-span prefabricated truss and the prefabricated column in the embodiment solves the situation that direct rigid connection causes vicious cycle of the prefabricated truss and the prefabricated column to increase the section, and also meets the requirements of guaranteeing to bear wind resistance, earthquake resistance and accidental action in the construction later stage. The node first connects the connecting plate 4, the temporary corbel 7 and the low-friction sliding pad 8 to support the prefabricated truss, so that the web member 2 and the chord 3 can all meet the requirement of small displacement along the transverse direction, which causes the node to slightly rotate, reduces the bending stress of the supporting column 1, and also reduces the horizontal tension of the chord 3 transmitted to the supporting column 1, so as to realize the hinged connection and sliding between the prefabricated truss and the prefabricated column. Then the truss node plate 6 of the prefabricated truss and the column node plate 5 of the supporting column 1 are fixed by welding, and the truss node plate 6 between the web member 2 and the chord 3 is welded to transmit force, so as to realize rigid connection of the node.

[0059] The above specific embodiments are preferred embodiments of the utility model, and cannot limit the utility model, and any change or other equivalent replacement mode without departing from the technical scheme of the utility model is included in the protection scope of the utility model.

Claims

1. A hinged-then-rigid joint for a large-span precast truss and precast column, characterized in that: The system includes precast columns, connecting plates, precast trusses, temporary corbels, friction sliding pads, and steel frame beams. The steel frame beams and the temporary corbels are welded to the precast columns. The temporary corbels are located below the precast trusses. The temporary corbels support the bottom of the nodes of the precast trusses through the friction sliding pads. The side of the nodes of the precast trusses is connected to one end of the connecting plate by bolts, and the other end of the connecting plate is connected to the side of the precast columns by bolts. The prefabricated truss includes web members, chord members, and truss node plates. The chord members are connected to the web members through the truss node plates. The bottom of the truss node rests on the top of the friction sliding pad. The side of the truss node plate is connected to one end of the connecting plate by bolts. The precast column includes a support column and a column node plate. The support column is welded to one end of the column node plate, and the other end of the column node plate is connected to the connecting plate by bolts.

2. The hinged-then-rigid joint of a large-span precast truss and precast column according to claim 1, characterized in that: The prefabricated truss also includes a post-welded web and a post-welded flange. The two sides of the post-welded web are welded to the prefabricated column, and the two sides of the post-welded flange are welded to the truss node plate of the prefabricated truss.

3. The hinged-then-rigid joint of a large-span precast truss and precast column according to claim 1, characterized in that: The structure of the web member can be either I-shaped or box-shaped.

4. The hinged-then-rigid joint of a large-span precast truss and precast column according to claim 1, characterized in that: The structure of the chord includes I-beam or box-type.

5. The hinged-then-rigid joint of a large-span precast truss and precast column according to claim 1, characterized in that: The supporting columns include steel columns or steel-concrete composite columns.

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