A construction method for starting from the middle without cables for an arch reticulated shell

Abstract

A construction method for starting in the middle without cables for an arch reticulated shell, characterized by the following steps: First, select the starting unit grid. The starting unit grid is selected at the middle position in the length direction of the entire grid. The length of the starting unit grid is the span of the grid, and the width is one wheelbase. Second, use the model of the grid for simulation verification to find out the over-stressed members and bolts. Third, replace the members and bolts that do not meet the requirements after verification, and then re-verify until all members and bolts meet the requirements. Fourth, according to the width of the stacker-reclaimer foundation, after simulation verification and physical lofting, assemble from the arch top of the starting unit grid to both sections, and then hoist the crane across the stacker-reclaimer foundation. Fifth, divide into two groups and continue to install the starting unit grid on both sides of the stacker-reclaimer foundation simultaneously until the installation of the entire starting unit grid is completed. The present invention has the advantages of short construction period and greatly reduced construction cost.

Description

Technical Field

[0001] The present invention relates to a steel structure technology, in particular to a reticulated shell construction technology, and specifically to a construction method for starting in the middle of an arch-shaped reticulated shell without stay cables. Background Art

[0002] For decades, arch-shaped reticulated shell products have been widely used in industries such as coal, electricity, cement, steel, and chemical industries. The demand in domestic and foreign markets is very large. Especially in recent years, in order to beautify the environment and meet environmental protection requirements, the number of reticulated shell coal storage sheds has increased significantly, and most of them have a span of about 100m or even larger.

[0003] At present, most of the reticulated shell coal storage sheds adopt an arch-shaped cylindrical structure. The model and simulation calculation of the space frame have become industry standards. When designing the space frame, it is usually necessary to calculate the stress values of the members and bolts, and determine whether the stresses received by each member and bolt are within the standard range according to the standard. The installation of the arch-shaped space frame first requires the installation of the starting space frame, and the remaining space frames are assembled in bulk based on the starting space frame, and finally the installation of the entire space frame is completed. The most critical and important step in the entire construction process is the installation of the starting space frame. Domestic engineering and technical personnel have continuously studied various construction methods for installing the starting space frame. At present, the installation methods for the starting space frame of the arch-shaped space frame in China include: "gable starting method", "single-sided arching method", "block aerial docking method", etc. These methods have some common characteristics. For example, stay cables must be set during the construction process, the construction period is about 7 - 10 days, the construction cost is high, the installation accuracy requirements during the construction process are high, and the safety is relatively low. How to reduce the construction period and cost of the starting space frame, reduce the construction difficulty, and at the same time ensure the construction quality and safety is a problem that professional and technical personnel have racked their brains to explore for many years. Summary of the Invention

[0004] The purpose of the present invention is to invent a construction method for starting in the middle of an arch-shaped reticulated shell without stay cables, aiming at the problems existing in the commonly used methods for starting the arch-shaped reticulated shell, such as long construction period, high construction cost, high installation accuracy requirements during the construction process, and relatively low safety.

[0005] The technical solution of the present invention is as follows:

[0006] A construction method for starting in the middle of an arch-shaped reticulated shell without stay cables, characterized in that it includes the following steps:

[0007] First, select the starting unit space frame, select the middle position in the length direction of the entire space frame. The length of the starting unit space frame is the span of the space frame, and the width is one wheelbase;

[0008] Second, use the model of the space frame for simulation calculation to find out the over-stressed members and bolts;

[0009] Third, replace the rods and bolts that do not meet the requirements of the empirical calculation, and then recalculate until all rods and bolts meet the requirements;

[0010] Fourth, according to the width of the stacker-reclaimer foundation, after simulation verification and physical layout, the grid arch of the starting unit is assembled into two sections, and then hoisted across the stacker-reclaimer foundation by crane;

[0011] Fifth, divide into two groups and continue to install the starting unit grid on both sides of the stacker-reclaimer foundation at the same time until the entire starting unit grid is installed.

[0012] The starting grid is installed symmetrically starting from the arch, and no cables are required during the installation process.

[0013] In order to ensure the stability of the starting grid installation process, the entire starting grid is installed at a constant speed from the arch to both sides. When the starting grid is installed to the support position, do not unload it immediately. At this time, continue to install a grid with a wheelbase width in the axial direction at the support position to increase the length of the grid at the support position and ensure the stability of the starting grid structure.

[0014] The entire installation period of the starting grid is two days. On the first day, the starting grid is assembled from the arch, across the stacker-reclaimer foundation, and then a crane is used at each end to continue lifting it to the designated position. On the second day, two cranes are used at each end to continue lifting until the installation of the starting grid is completed. To ensure the stability of the grid structure, the four cranes do not change the lifting points or loosen the hooks during the entire lifting process on the second day. This method greatly shortens the construction period compared to the installation of conventional starting grids.

[0015] The present invention is applicable to all arch bolt ball grids that have passed design verification.

[0016] Beneficial effects of the present invention:

[0017] The present invention is a new construction method invented by the applicant after long-term exploration and engineering practice. During the installation process, there is no need to set cables, which reduces the construction difficulty; the construction period is only two days, which greatly shortens the construction period and reduces the construction cost; the supports at both ends are in place at the same time, which reduces the accuracy requirements for the starting grid to be in place or docked, and ensures the construction quality.

[0018] Compared with the prior art, the economic effect of the present invention is shown in Table 1.

[0019] Table 1 Comparison of beneficial effects

[0020]

[0021] Conclusion: Under the same conditions, compared with several commonly used construction methods in China at present, the construction period and cost of the construction method of the present invention are significantly reduced; the cable is cancelled, reducing the construction difficulty; there is no high-altitude operation throughout the process, ensuring construction safety; the two ends are simultaneously seated on the supports, reducing the closing difficulty of the starting grid. Brief Description of the Drawings

[0022] Figure 1 It is the plan view of the starting grid of the present invention.

[0023] Figure 2 It is the position diagram of the members that need to be replaced due to overstress of the starting grid of the present invention.

[0024] Figure 3 It is the three-dimensional schematic diagram of the installation process of the starting grid of the present invention.

[0025] Figure 4 It is the schematic diagram of the installation direction (from top to bottom) of the present invention.

[0026] Figure 5 It is the simplified diagram of the hoisting process of the starting grid of the present invention.

[0027] Figure 6 It is the simplified diagram of the bulk direction after the support of the starting grid of the present invention is fixed. Detailed Description of the Invention

[0028] The present invention will be further described below in conjunction with the drawings and embodiments.

[0029] As Figure 1-6 shown.

[0030] An intermediate starting construction method for an arch reticulated shell without cables, characterized in that it comprises the following steps:

[0031] First, review various parameters such as the axis, elevation, and support surface position of the grid foundation, and determine the starting unit grid of the reticulated shell; the starting unit grid is generally selected in the middle part of an independent section of the grid, so that after the starting grid is installed, it can be bulked to both sides at the same time, shortening the construction period, and the width is one wheelbase. As Figure 1 shown.

[0032] Second, according to the local wind load standard value and the temperature condition during installation, select and find out the overstressed members and bolts in the starting grid through simulation calculation.

[0033] Third, replace the overstressed members and bolts in the starting grid, and then re-perform simulation calculation until all materials meet the requirements, as Figure 2 shown.

[0034] Fourth, after the simulation calculation of the starting unit is completed, start the assembly and hoisting of the starting grid.

[0035] Fifth, the installation sequence of the starting unit is to start from the vault and install towards the two end supports. During the installation process, the lifting points of the crane should be selected according to the lifting points obtained from the simulation calculation, and it is absolutely not allowed to change the lifting points; as Figure 3 shown.

[0036] Sixth, after the supports are in place, it is necessary to continue installing a grid with a width of one grid distance to ensure the stability of the entire starting grid. During this period, the crane does not release the hook.

[0037] Seventh, after the installation of the starting grid is completed, the crane unloads.

[0038] The key control points in the specific implementation process of the present invention are as follows:

[0039] 1. The starting unit grid must be a grid with a width of one grid distance. After selecting the starting unit grid, use the model for simulation calculation to find the over-stressed components and replace them.

[0040] 2. Considering safety and project quality, the installation direction of the arch must be from top to bottom (as Figure 4 shown).

[0041] 3. During the entire hoisting process of the starting grid, all lifting points are determined through model simulation calculation. Therefore, to ensure the safety of the construction process, the hoisting is carried out strictly according to the lifting points set in the plan during the construction of the starting grid.

[0042] 3. At the beginning of the hoisting process of the starting unit grid, two cranes are used for simultaneous hoisting. When the grid is installed to about 1 / 2 of the entire starting unit grid, to ensure the stability of the grid, the starting grid needs to be widened by half a grid on both the left and right, with a continuous length of two grids. At this time, the two-crane simultaneous hoisting is changed to four-crane simultaneous hoisting. After that, the lifting points are not changed. When the grid is installed to three grids after this lifting point, the grid is lowered to the ground and the positions of the cranes are adjusted. Subsequently, the four cranes lift the grid simultaneously and continue the hoisting until the installation of the entire starting grid is completed. During this process, the four cranes are strictly prohibited from releasing the hook. As Figure 5 shown.

[0043] 4. When the starting unit grid just lands on the support, it needs to be adjusted by the crane so that the center of the support of the starting unit grid falls on the designed center position of the embedded part, and then it is fixed. During the entire process, the four cranes cannot release the hook. After the supports of the starting unit grid are in place, continue to install the grid in bulk on both the left and right sides to increase the stiffness of the starting unit. Install as much as possible, the more the better. To ensure construction safety, the crane still does not release the hook during this process until the width of the grid below the lifting point of the starting grid is at least two grid distances. At this time, all supports are fixed and the installation of the starting unit is completed. As Figure 6 shown.

[0044] V. Multiple cranes are required for simultaneous hoisting during the entire hoisting process. In order to control the synchronization of the cranes, a dedicated person must be employed to give commands. Then, each crane is numbered, and based on the crane number and the lifting point reaction force, commands are given to each crane one by one according to a proportion of 5% for each loading (unloading) operation.

[0045] Parts not involved in the present invention are the same as or can be implemented using the prior art.

Claims

1. A construction method for starting in the middle without cables for an arch reticulated shell, characterized in that: It includes the following steps: First, select the starting unit grid. The starting unit grid is selected at the middle position in the length direction of the entire grid. The length of the starting unit grid is the span of the grid, and the width is the width of one axle distance. Second, use the model of the grid for simulation and verification to find out the over-stressed members and bolts. Third, replace the members and bolts that do not meet the requirements after verification, and then re-verify until all members and bolts meet the requirements. Fourth, according to the width of the stacker-reclaimer foundation, after simulation verification and physical lofting, assemble from the crown of the starting unit grid to both ends, and then use a crane to hoist it across the stacker-reclaimer foundation. Fifth, divide into two groups and continue to install the starting unit grid on both sides of the stacker-reclaimer foundation at the same time until the installation of the entire starting unit grid is completed. The starting unit grid is symmetrically installed starting from the crown, and no guy wires need to be set during the installation process. To ensure the stability of the installation process of the starting unit grid, the installation speed of the entire starting unit grid from the crown to both sides is quite the same. When the starting unit grid is installed to the support position, do not unload immediately. At this time, continue to install a grid with a width of one axle distance in the axial direction at the support position to increase the length of the grid at the support position and ensure the stability of the structure of the starting unit grid.

2. The construction method according to claim 1, characterized in that: the whole The installation period of the starting unit grid is two days. On the first day, the starting unit grid is assembled from the crown, crosses the stacker-reclaimer foundation, and then is continuously hoisted to the designated position by one crane at each end. On the second day, two cranes are used at each end to continue hoisting until the installation of the starting unit grid is completed. To ensure the stability of the structure of the starting unit grid, during the entire hoisting process on the second day, the four cranes do not change the lifting points and do not loosen the hooks. This method greatly shortens the construction period compared with the conventional installation of the starting unit grid.

3. The construction method according to claim 1, characterized in that: It is applicable to all arched bolted spherical grids that pass the design verification.

Images