Construction method of open-web steel truss connecting towers

Abstract

The application discloses a construction method of a space truss steel truss connecting two towers, S1: before the truss installation, a bracket is reserved on the installation position of the two towers according to the layer number of the truss chord; S2: the horizontal chord, the inclined web member and the straight web member of the truss are prepared on the ground platform; S3: the space truss steel truss is assembled from the two towers to the middle at the same time, the horizontal chord of each section is installed and then the tread plate is laid on the horizontal chord, the next section of the horizontal chord is assembled forwardly by taking the tread plate as a construction platform; the outer end of the horizontal chord is pulled and connected with the upper structure through the inclined pull rod, the truss is assembled from the two towers to the middle, the already assembled structure is used as a construction platform, and a foot platform needs not to be additionally built; the hoisting and installation are implemented by taking each rod member as a unit, large lifting equipment is not needed, and the construction investment is greatly reduced compared with the prior art.

Description

Technical Field

[0001] This invention relates to the field of high-altitude bridge installation technology, specifically a construction method for a hollow steel truss structure connecting towers. Background Technology

[0002] In current architectural design, it's common to incorporate connected structures between two buildings. This allows for better pedestrian access and enhances the building's visual appeal due to its unique shape. Connected structures typically use steel as the main support, upon which concrete and decorative structures are then built, creating a unified architectural form. The main support of a connected structure is generally a standard steel truss, a hollow steel truss structure, or a hybrid steel truss structure. The span of the connected steel truss is generally between 10 and 30 meters; exceeding this length usually requires intermediate supports. The connected steel truss contains multiple layers of truss members along its height, with the hollow truss consisting of multiple layers and sections of tie rods. Connections to the adjacent towers can be rigid, hinged, sliding, or flexible.

[0003] This invention primarily addresses the construction of directly connected steel trusses. Existing construction methods for high-altitude connecting structures generally involve assembling the entire structure on the ground and then lifting it as a whole using hydraulic equipment. This installation method has the following disadvantages: 1) Due to the large load-bearing capacity of the connected structure after ground assembly, large lifting equipment is required, which is expensive, resulting in high construction costs; 2) Horizontal positioning is difficult during high-altitude hoisting of this structure, generally requiring vertical hoisting. Therefore, the connected structure is usually assembled on a platform directly below the installation location. However, many building designs incorporate cantilever structures at the bottom. To protect the vertical hoisting, assembly is often performed on the lower roof of the lower annex. The roof itself has limited load-bearing capacity, necessitating the installation of a supporting structure beneath the roof, increasing construction costs. Summary of the Invention

[0004] This invention aims to solve the problems of large investment in installation equipment for existing steel truss structures, large workload of auxiliary temporary construction outside the connected structure, and long construction period, and thus provides a construction method for a hollow steel truss structure connected between towers.

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

[0006] A construction method for a hollow steel truss structure connecting towers: S1: Before truss installation, brackets are reserved at the installation positions on both sides of the towers according to the number of truss chord layers; S2: Horizontal chords, diagonal web members, and straight web members of the truss are prepared on the ground platform; S3: The hollow steel truss is assembled synchronously from both sides of the towers toward the middle. After the horizontal chord of each segment is installed, a tread plate is laid on it, and the tread plate is used as a construction platform to assemble the next segment of the horizontal chord; the outer ends of the horizontal chords are connected to the superstructure through diagonal braces.

[0007] The present invention, which adopts the above technical solution, has the following prominent features compared with the prior art:

[0008] This invention assembles the truss from the two side towers toward the middle, and then uses the basically assembled structure as a construction platform, eliminating the need to build a separate scaffolding platform. This invention implements hoisting and installation on a per-member basis, and small lifting equipment is sufficient for construction, greatly reducing construction costs compared to existing methods.

[0009] Preferably, the assembly process of the steel truss is as follows:

[0010] The first step is to hoist the first section of the first layer of horizontal chord to the installation position; while it is being hoisted, fix the first section of the first layer of horizontal chord to the first layer of corbel; then lay the treads on the first section of the first layer of horizontal chord.

[0011] The second step is to hoist the first section of the first layer of diagonal web members. The lower end of the first section of the first layer of diagonal web members is fixed to the outer cantilever end of the first section of the first layer of horizontal chord members, and the upper end is fixed to the second layer of corbels.

[0012] The third step is to first fix the first section of the horizontal chord to the second corbel as described in the first step; second install the first section of the diagonal web member as described in the second step; third install the first section of the straight web member as described in the second step; and finally install the second section of the horizontal chord and the second section of the diagonal web member.

[0013] The fourth step involves assembling the hollow steel truss towards the center, as described in the third step. Before pre-installing the next section of the horizontal chord on a certain floor, first install the previous section of the horizontal chord and the previous section of the diagonal web members on the previous floor. Then install the straight web members of the previous section on this floor. Finally, install the horizontal chord of this floor and use diagonal web members to connect the outer cantilever end of the horizontal chord of this floor to the previous section of the horizontal chord on the previous floor. If diagonal web members are not designed on this section of the horizontal chord, temporary diagonal bracing is used instead of diagonal web members.

[0014] Fifth step: When the steel trusses on both sides are advanced to a distance less than the length of the horizontal chord, reserve the post-assembly section; after all layers of the steel trusses on both sides are assembled, hoist the horizontal tie rods into the post-assembly section, and use the horizontal tie rods to connect the horizontal chords of each layer on both sides of the post-assembly section.

[0015] The sixth step is to gradually remove the temporary diagonal bracing from the middle of the steel truss outwards to both sides, so that the steel truss body is gradually subjected to stress.

[0016] Preferably, before the steel truss is installed, the camber value of each chord segment is determined through structural calculations. Referring to the data determined by the calculations, the outer cantilever end of each horizontal chord is fixed upwards during installation, so that after the final installation, the position of the chord on the outer side of the two trusses is in the position required by the design calculations.

[0017] Preferably, a suitable temperature environment is selected, horizontal tie rods are installed, and the closure construction of the steel trusses on both sides is carried out.

[0018] Preferably, during the assembly process, the horizontal chord, diagonal brace, and straight brace are first bolted in place, and then the angles are adjusted according to the camber requirements before welding. The temporary diagonal brace is fixed with detachable bolts at both ends. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the installation of the first horizontal chord and diagonal web member of the first layer of the present invention;

[0020] Figure 2 is a schematic diagram of the pre-installation members before the installation of the second section of the first layer of horizontal chord;

[0021] Figure 3 Schematic diagram of the installation and fixing of the second section of the first layer horizontal chord;

[0022] Figure 4 A schematic diagram showing the provision of a post-assembly section for the assembly of the trusses on both sides;

[0023] Figure 5 A schematic diagram showing the rear-mounted sections for upward assembly of the trusses on both sides;

[0024] Figure 6 A schematic diagram showing the completed assembly of the two trusses;

[0025] Figure 7 This is a diagram showing the layout of the diagonally braced trusses on both sides of the building.

[0026] Figure 8 A schematic diagram showing the connection of the two trusses in the rear section;

[0027] Figure 9 This is a schematic diagram showing the temporary tie rod after it has been removed.

[0028] Figure 10 The overall load of the truss falls on the truss body (see diagram).

[0029] Figure 11 A structural diagram of the corbel joint on the tower;

[0030] Figure 12 This is a structural diagram of the end node of the temporary tie rod.

[0031] In the diagram: 1. Tower; 2. First floor corbel; 3. Second floor corbel; 4. First floor first horizontal chord; 5. First floor first diagonal web member; 6. Previous floor horizontal chord; 7. Previous floor diagonal web member; 8. Previous floor straight web member; 9. Temporary diagonal tie rod; 10. Next floor horizontal chord; 11. Horizontal tie rod. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments, which are intended only to provide a better understanding of the invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0033] See Figures 1 to 6 This invention provides a construction method for a hollow steel truss structure connecting towers, comprising: S1: Before truss installation, pre-reserving corbels at the installation positions of the two towers 1 according to the number of truss chord layers; S2: Preparing the horizontal chords, diagonal web members, and straight web members of the truss on a ground platform; S3: Simultaneously assembling the hollow steel truss from the two towers 1 towards the middle, laying a tread on each segment of the horizontal chord after installation, using the tread as a construction platform to assemble the next segment of the horizontal chord; the outer ends of the horizontal chords are connected to the upper structure by diagonal braces.

[0034] The assembly process of the steel truss in this invention is as follows:

[0035] The first step is to hoist the first section of the first layer horizontal chord 4 to the installation position; while it is being hoisted, fix the first section of the first layer horizontal chord 4 to the first layer bracket 2; then lay the treads on the first section of the first layer horizontal chord 4.

[0036] The second step is to hoist the first section of the first layer of diagonal web members 5. The lower end of the first section of the first layer of diagonal web members 5 is fixed to the outer cantilever end of the first section of the first layer of horizontal chord members 4, and the upper end is fixed to the second layer of corbels 3. See [link / reference]. Figure 1 , Figure 11 .

[0037] Step 3, see Figure 2 , Figure 3 Before installing the second section of the first layer horizontal chord 10, first ① fix the first section of the second layer horizontal chord 6 and the second layer corbel 3 as described in the first step; ② then install the first section of the second layer diagonal web member 7 as described in the second step; ③ then install the first section of the first layer straight web member 8; ④ finally install the second section of the first layer horizontal chord 10 and the second section of the first layer diagonal web member.

[0038] Fourth, following the steps described in step three, proceed with the assembly of the hollow steel truss towards the center. Before installing the next horizontal chord member of this layer (e.g., the second horizontal chord member 10 of the first layer), first install the previous horizontal chord member and the previous diagonal web member of the layer above it (e.g., the first horizontal chord member 6 and the first diagonal web member 7 of the second layer); then install the previous straight web member of this layer (e.g., the first straight web member 8 of the first layer); finally install the horizontal chord member (i.e., the second horizontal chord member 10 of the first layer), and use diagonal web members to connect the outer cantilever end of this horizontal chord member to the previous horizontal chord member of the layer above; if no permanent diagonal web members are designed on this horizontal chord member, temporary diagonal bracing 9 is used for connection. See also... Figure 3 , Figure 4 The installation sequence of each member shall be in accordance with the numbering shown in the diagram.

[0039] Step 5, see Figure 5 , Figure 6 , Figure 7 When the distance between the two trusses is less than the length of the horizontal chord, a post-assembly section is reserved; after the two trusses are assembled, the horizontal chords of each layer of the post-assembly section are connected by horizontal tie rod 11.

[0040] Step 6, see Figure 8 , Figure 10 After gradually removing the temporary diagonal bracing 9 and allowing the truss body to gradually bear the load, the construction of other structures connecting the truss was carried out, and the construction of the connecting structure was completed.

[0041] It should be noted that in cantilever construction, deflection estimation is an important step to ensure structural standards. Before truss installation, structural calculations are performed to determine the camber value of each chord segment. Referring to the calculated data, the cantilever ends of the horizontal chords on each floor are fixed upwards during installation, so that after final installation, the chord positions on the outer sides of the trusses on both sides are in the positions required by the design calculations. A suitable temperature environment is selected, connecting rods are installed, and the closure construction of the trusses on both sides is carried out.

[0042] Preferred, see Figure 11 During the assembly of the truss members, the permanent horizontal chords, diagonal web members, and straight web members are first bolted in place, and then welded in place after the angles are adjusted according to the required camber. (See also...) Figure 12 The temporary diagonal brace 9 is fixed at both ends with bolts.

[0043] Feasibility and rationality analysis of the above construction method:

[0044] The main building was completed, forming a rigid structure; the main building's settlement was completed, reducing the additional stress caused by the uneven settlement of the main buildings on both sides after the construction truss was erected.

[0045] The connecting structure is rigidly connected to the main buildings on both sides. In the design, the load of the connecting structure is transferred to the main building structure through the ends of the truss. During construction, no secondary beams or floor slabs are constructed, and the total self-weight load is relatively small. It is also transferred to the main building structure through both ends of the truss, which is the same as the design assumption.

[0046] The temporary tie rods serve two purposes: first, they ensure that the web members and chords of the open truss do not generate or generate minimal bending moments during construction; second, they allow for adjustment of the camber and deflection of the truss chords.

[0047] The final construction of the closure section has the following advantages: a. It can be used to adjust the construction error of the cantilevered sections of the trusses on both sides of the point; b. The final closure can reduce the construction stress during the construction process; c. The closure can be carried out at a suitable temperature to reduce the temperature stress of the structure; d. After closure, the temporary tie rods can be gradually removed and unloaded, which can achieve the one-time formation of the stiffness of the connecting structure and slowly load it onto the main building structure.

[0048] In summary, the above-mentioned construction method for the connecting structure is reasonable and avoids the adverse effects of additional stress that may be generated during the construction process on the main structure.

[0049] This invention maximizes the use of the existing structure's permanent and temporary bonding function while maintaining the original structure's stress and load-bearing requirements. This reduces construction difficulty, lowers material costs, improves construction efficiency, and ensures construction quality. During the gradual installation and closure of the closure section, the structure experiences no additional load at that point. After the temporary tie rods are gradually removed and unloaded, the connecting truss begins to bear load. The stress and loading modes are consistent with the design calculations, with no additional construction stress, thus meeting the structural design stress requirements.

[0050] This invention, based on the existing concept of cantilever construction, assembles the connected structure from both sides of tower 1 towards the middle, breaking through the traditional construction concept of installing the entire connected structure as a whole. Instead, it breaks down the steel truss into individual members for separate hoisting. This invention uses the already constructed structure as a construction platform, eliminating the need for additional scaffolding platforms and thus solving the problem of time-consuming and labor-intensive temporary platform construction. Furthermore, by hoisting and installing each connecting rod as a unit, this invention significantly reduces the load requirements of hoisting equipment, eliminating the need for large lifting devices and resulting in a substantial reduction in construction investment compared to existing methods.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A construction method for a hollow steel truss structure connecting towers, characterized in that: S1: Before the truss is installed, make reservations for corbels at the installation positions of the towers on both sides according to the number of truss chord layers; S2: Prepare the horizontal chords, diagonal web members, and straight web members of the truss on the ground platform; S3: The hollow steel truss is assembled simultaneously from both side towers towards the middle. After the horizontal chord of each segment is installed, a treadmill is laid on top, using the treadmill as a construction platform to assemble the next horizontal chord segment. The outer ends of the horizontal chords are connected to the superstructure via diagonal braces. The truss assembly process is as follows: The first step is to hoist the first section of the first layer of horizontal chord to the installation position; while it is being hoisted, fix the first section of the first layer of horizontal chord to the first layer of corbel; then lay the treads on the first section of the first layer of horizontal chord. The second step is to hoist the first section of the first layer of diagonal web members. The lower end of the first section of the first layer of diagonal web members is fixed to the outer cantilever end of the first section of the first layer of horizontal chord members, and the upper end is fixed to the second layer of corbels. The third step is to first fix the first section of the horizontal chord to the second corbel as described in the first step; second install the first section of the diagonal web member as described in the second step; third install the first section of the straight web member as described in the first step; and finally install the second section of the horizontal chord and the second section of the diagonal web member. The fourth step involves assembling the hollow steel truss towards the center, as described in the third step. Before pre-installing the next section of the horizontal chord on a certain floor, first install the previous section of the horizontal chord and the previous section of the diagonal web members on the floor above it; then install the previous section of the straight web members on this floor; finally, install the horizontal chord and use diagonal web members to connect the outer cantilever end of the horizontal chord to the previous section of the horizontal chord on the floor above; if no permanent diagonal web members are designed on the horizontal chord, temporary diagonal braces are used to replace the diagonal web members for connection. Fifth step: When the steel trusses on both sides are advanced to a distance less than the length of the horizontal chord, reserve the post-assembly section; after all layers of the steel trusses on both sides are assembled, hoist the horizontal tie rods into the post-assembly section, and use the horizontal tie rods to connect the horizontal chords of each layer on both sides of the post-assembly section. The sixth step is to gradually remove the temporary diagonal bracing from the middle of the steel truss outwards to both sides, so that the steel truss body is gradually subjected to stress.

2. The construction method of the hollow steel truss structure connecting towers according to claim 1, characterized in that: Before the steel truss is installed, structural calculations are performed to determine the camber value of each chord segment. Based on the calculated data, the outer cantilever ends of each horizontal chord are fixed upwards during installation, so that after final installation, the chord positions on the outer sides of the trusses are in the positions required by the design calculations.

3. The construction method of the hollow steel truss structure connecting towers according to claim 1, characterized in that: Select a suitable temperature environment, install horizontal tie rods, and carry out the closure construction of the steel trusses on both sides.

4. The construction method of the hollow steel truss structure connecting towers according to claim 1, characterized in that: During the assembly process, the permanent horizontal chord, diagonal brace, and straight brace are first bolted in place, and then the angles are adjusted according to the camber requirements before welding. The temporary diagonal brace is fixed with detachable bolts at both ends.

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