Method for reinforcing existing basement used as underground diaphragm wall hoisting platform

Abstract

The invention discloses an existing basement reinforcing method used as an underground diaphragm wall hoisting platform, and relates to the technical field of building construction. According to the method, on the basis of an existing basement structure, steel supporting stand columns are built in the basement structure layer by layer from bottom to top, the upper-layer steel supporting stand columns and the lower-layer steel supporting stand columns are vertically stacked and overlapped, and the supporting stand columns are arranged at intervals according to measured overall load pressure; the steel supporting stand columns are connected with concrete supporting columns in an existing basement through I-shaped steel, so that it is guaranteed that loads are transmitted up and down, and meanwhile transmission of the loads in the horizontal direction and the overall stability of a supporting system in the crawler crane construction process are guaranteed; dynamic compensation control is carried out through the automatic compensation servo system, multi-point supporting balance is guaranteed, and therefore effective reinforcement can be carried out according to the walking area of the crawler crane in an existing basement, normal operation of the crawler crane is guaranteed, and underground diaphragm wall construction is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and particularly to a method for reinforcing an existing basement used as a lifting and hoisting platform for diaphragm walls. Background Technique

[0002] Currently, with the development of the urban renewal process, the renovation and reconstruction of old buildings in the city centers of megacities such as Beijing and Shanghai will face the problem of narrow construction sites. At the same time, during the construction process, the municipal government has strict requirements for the construction process. Except in absolute cases, it is necessary to ensure that there is no impact on the surrounding access roads during the construction process. Facing such a situation, only in-situ reconstruction can be selected. At this time, the basement top slab of the original building needs to be used as the construction site.

[0003] However, in the actual construction process, when hoisting and installing large steel reinforcement cages, a crawler crane needs to be used for hoisting. The crawler crane itself has a large mass, and at the same time, the mass of the hoisted steel reinforcement cage is also very large. This makes the structural strength of the basements of existing old buildings insufficient and unable to realize such a construction method, resulting in the need to break the whole into parts during the overall construction process, increasing the overall construction period and construction difficulty. Therefore, a method for reinforcing an existing basement used as a lifting and hoisting platform for diaphragm walls is provided to solve the above problems. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a method for reinforcing an existing basement used as a lifting and hoisting platform for diaphragm walls, which solves the problem that in the case of demolishing and reconstructing in place, using the basement top slab of the original building as the construction site, while the structural strength of the basements of existing old buildings is insufficient and unable to support construction equipment.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A method for reinforcing an existing basement used as a lifting and hoisting platform for diaphragm walls, comprising the following steps:

[0006] Step 1: Determine the reinforcement range. According to the on-site conditions, conduct site planning and layout, determine the crawler crane construction walking area, and determine the actual reinforcement range in combination with the existing structural form according to the crawler crane walking area.

[0007] Step 2: Load calculation. The load calculation needs to consider the actual selected crawler crane load, the heaviest steel reinforcement cage load, the lifting appliance load, and the moving load coefficient of superimposed walking.

[0008] Let the self-weight of the crawler crane be H1, the weight of the lifting appliance be H2, the weight of the workpiece being lifted be H3, and the contact area between the crawler and the ground be S1; consider the impact coefficient and imbalance coefficient to be 1.2; consider a 1.4-fold combination coefficient when calculating the bearing capacity, and then consider a 5% positive error in the mass of the lifting appliance and the workpiece. Thus, the maximum bearing pressure at the base can be calculated as;

[0009]

[0010] Step 3. Determine the spacing of the steel support columns;

[0011] Step 4. Construction of the layout of the steel support columns. According to the existing basement structure, the steel support columns are arranged layer by layer upward from the basement subgrade to form a three-dimensional support space, so as to realize the reinforcement of the existing basement;

[0012] Step 5. Arrangement of the steel support jacks. Install the steel support jacks on the top of the steel support columns to compensate for the height difference between the steel support columns and the existing basement beams;

[0013] Step 6. Connection of the support automatic compensation servo system. Connect the automatic compensation servo system with the jack control to realize automatic support compensation;

[0014] Step 7. Arrangement of the deformation monitoring points, which are used to monitor the key support parts and the areas prone to deformation in the overall reinforcement area, so as to ensure the safety of the reinforcement area;

[0015] Step 8. Construction of the horizontal connection of the steel support columns;

[0016] Step 9. Arrangement of the structural roof supports;

[0017] Step 10. Construction of the concrete slab.

[0018] Preferably, the reinforcement range in Step 1 needs to be considered according to the whole span of the crawler crane, and the reinforcement area is the walking area of the crawler crane during the diaphragm wall construction.

[0019] Preferably, the steel support columns adopt Q235 Ф609*16mm steel support columns. The spacing of the steel support columns is evenly distributed according to the spacing of the existing structural beams and columns, and is designed and distributed according to the total load pressure and the area of the column construction area. At the same time, the quality superposition after the construction of the upper load surface also needs to be considered.

[0020] Preferably, the existing basement includes the existing structural bottom slab, the existing structural middle slab beam, the existing structural beam and the vertically cast concrete columns. The steel support columns are vertically positioned and arranged between the existing structural bottom slab, the existing structural middle slab beam and the existing structural beam, and the upper and lower steel support columns overlap vertically to ensure the up and down transfer of the load.

[0021] Preferably, the jacks are automatically pressurized. One automatically pressurized jack is installed on each steel support column, and the automatically pressurized jack is arranged at the center position of the column. Through the automatic compensation servo system, the pressure of each group of automatically pressurized jacks is ensured to be the same, ensuring that the multi-point support forces of the steel support columns on the existing basement are the same, and automatically compensating for the lost support force during use.

[0022] Preferably, during the construction process of arranging the steel support columns, I-beams are installed between multiple steel support columns and between the steel support columns and the concrete columns of the existing basement, so as to ensure the transfer of horizontal loads during the construction process of the crawler crane and the overall stability of the support system.

[0023] Preferably, the I-beam and the end of the concrete column are fixed by expansion bolts.

[0024] Preferably, between the I-beam and the steel support column, by welding connecting plates on the steel support column, bolt holes are reserved on the end of the I-beam and the connecting plate, and they are fixed by high-strength bolts passing through the connecting plate and the bolt holes on the I-beam.

[0025] Preferably, a plain plate rubber bearing with a thickness of 100 mm is installed on the top of the steel support column at the existing structural beam, and then concrete slab construction is carried out on the top of the plain plate rubber bearing.

[0026] The present invention discloses a method for reinforcing an existing basement used as a lifting platform for diaphragm walls, and its beneficial effects are as follows: Based on the existing basement structure, steel support columns are built layer by layer from bottom to top in the basement structure, and the upper and lower steel support columns are vertically stacked and overlapped. The quantity and size of the steel support columns are arranged according to the overall load pressure calculated in advance. And the steel support columns and the concrete columns in the existing basement are connected by I-beams to ensure the up and down transfer of loads, and at the same time ensure the transfer of horizontal loads during the construction process of the crawler crane and the overall stability of the support system. Then, automatic pressure jacks are installed on the top of each group of steel support columns, and dynamic compensation control is carried out through an automatic compensation servo system to ensure balanced multi-point support. Thus, the existing basement can be effectively reinforced according to the walking area of the crawler crane, ensuring the normal operation of the crawler crane and facilitating the construction of diaphragm walls. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a flow chart of the reinforcement method of the present invention;

[0029] Figure 2 It is a schematic diagram of the reinforcement construction area planning of the present invention;

[0030] Figure 3 It is a cross-sectional view of the basement reinforcement structure of the present invention;

[0031] Figure 4 This is a schematic diagram of the construction of the crawler crane of the present invention;

[0032] Figure 5 This is a top view of the basement reinforcement structure of the present invention;

[0033] Figure 6 This is a schematic diagram of the installation structure of the I-beam and the basement concrete pillar of the present invention;

[0034] Figure 7 This is a schematic diagram of the installation structure of the I-beam and the supporting steel column of the present invention. Detailed implementation manners

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] The embodiment of the present application provides a method for reinforcing an existing basement used as a lifting platform for diaphragm walls, which solves the problem that in the case of demolition and reconstruction construction, the basement roof of the original building is used as the construction site, but the structural strength of the basement of existing old buildings is insufficient to support construction equipment.

[0037] To better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the specification drawings and specific implementation manners.

[0038] The embodiment of the present invention discloses a method for reinforcing an existing basement used as a lifting platform for diaphragm walls. As shown in the appendix Figure 1-7 shown, the method includes the following steps:

[0039] Step 1: Determine the reinforcement range. According to the on-site conditions, conduct site planning and layout, determine the crawler crane construction walking area, and determine the actual reinforcement range in combination with the existing structure form according to the crawler crane walking area. The reinforcement range needs to be considered for the entire span of the crawler crane, and the reinforcement area is the walking area of the crawler crane during diaphragm wall construction.

[0040] Step 2: Load calculation. The load calculation needs to consider the actually selected crawler crane load, the heaviest steel cage load, the sling load, and the moving load coefficient of superimposed walking;

[0041] Let the self-weight of the crawler crane be H1, the weight of the lifting appliance be H2, the weight of the workpiece being lifted be H3, and the contact area between the crawler and the ground be S1; consider the impact coefficient and the unbalance coefficient to be 1.2; when calculating the bearing capacity, consider a combined coefficient of 1.4, and then consider a positive error of 5% in the mass of the lifting appliance and the workpiece, from which the maximum pressure on the foundation can be calculated as;

[0042]

[0043] In actual application, assume that a 300t crawler crane is used, with a self-weight of 276t, a lifting appliance of about 5t, and a steel reinforcement cage being lifted of 40t;

[0044] The crawler contact area of the 300t crawler crane is 8×1.55×2 = 24.8m2;

[0045] The total weight during load walking is 276 + [(40 + 5)×1.05] = 323.3t;

[0046] Consider the impact coefficient and the unbalance coefficient of 1.2: 323.3×1.2 = 387.9t;

[0047] Foundation pressure: Pk = 387.9×9.8÷24.8 = 153.3kPa;

[0048] Taking Pk = 153.3kPa as the standard value for calculation, when calculating the bearing capacity, consider a combined coefficient of 1.4, then the comprehensive expansion coefficient of the crane load Pk max = 153.3×1.4 = 214.62kPa.

[0049] Step 3: Determine the spacing of the steel support columns. The steel support columns adopt Q235 Ф609*16mm steel support columns. The spacing of the steel support columns is evenly distributed according to the spacing of the existing structure beam columns. Design the distribution according to the total load pressure and the area of the column construction area. At the same time, the quality superposition after the construction of the upper load surface also needs to be considered.

[0050] Step 4: Construction of the layout of the steel support columns. According to the existing basement structure, the steel support columns are arranged layer by layer upward from the basement floor to form a three-dimensional support space, thereby realizing the reinforcement of the existing basement. The existing basement includes the existing structure floor slab, the existing structure middle slab beam, the existing structure beam, and the vertically cast concrete columns. By vertically positioning and arranging the steel support columns between the existing structure floor slab, the existing structure middle slab beam, and the existing structure beam, and the upper and lower layer steel support columns are vertically overlapped to ensure the up and down transmission of the load.

[0051] Step 5: Arrangement of the steel support jacks. Install steel support jacks at the top of the steel support columns to compensate for the height difference between the steel support columns and the existing basement beams. The jacks are automatically pressurized. One automatically pressurized jack is installed on each steel support column, and the automatically pressurized jack is arranged at the center position of the column.

[0052] Step 6: Connect the support automatic compensation servo system. Connect it to the jack control through the automatic compensation servo system to achieve automatic support compensation. Ensure that the pressure of each group of automatic pressurizing jacks is the same through the automatic compensation servo system, so as to ensure that the steel support columns have the same multi-point supporting force on the existing basement, and automatically compensate for the lost supporting force during use.

[0053] Step 7: Arrange deformation monitoring points, which are used to monitor the key supporting parts and the areas prone to deformation in the overall reinforcement area, so as to ensure the safety of the reinforcement area.

[0054] Step 8: Construction of horizontal connection of steel support columns. During the construction process of arranging the steel support columns, I-beams are installed between multiple steel support columns and between the steel support columns and the concrete columns of the existing basement to ensure the transfer of horizontal loads during the construction of the crawler crane and the overall stability of the support system. The I-beam and the end of the concrete column are fixed with expansion bolts. Between the I-beam and the steel support column, by welding connection plates on the steel support column, bolt holes are reserved on the end of the I-beam and the connection plate, and they are fixed by passing high-strength bolts through the connection plate and the bolt holes on the I-beam.

[0055] Step 9: Arrange the structural roof bearings. A common plate rubber bearing with a thickness of 100 mm is installed at the top of the steel support column at the existing structural beam.

[0056] Step 10: Concrete slab construction. Concrete slab construction is carried out on the top of the common plate rubber bearing. The concrete slab can be prefabricated and assembled, which has the advantages of fast construction speed, immediate installation and immediate use; it can also use the steel support column as a formwork frame, by erecting a formwork on its top and then pouring the concrete slab in-situ, so that the concrete slab has stronger integrity and durability, but the construction period is increased.

[0057] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for reinforcing an existing basement used as a lifting platform for diaphragm walls, characterized in that, It includes the following steps: Step 1: Determine the reinforcement scope, conduct site planning and layout according to the on-site conditions, determine the construction walking area of the crawler crane, and determine the actual reinforcement scope in combination with the existing structure form according to the crawler crane walking area; Step 2: Load calculation. The load calculation needs to consider the actually selected crawler crane load, the heaviest steel cage load, the sling load and the moving load coefficient of superimposed walking; Let the self-weight of the crawler crane be H1, the weight of the sling be H2, the weight of the workpiece being lifted be H3, and the contact area between the crawler and the ground be S1; consider the impact coefficient and unbalance coefficient to be 1.2; consider a 1.4-fold combination coefficient when calculating the bearing capacity, and then consider a 5% positive error in the mass of the sling and the workpiece, and thus the maximum bearing pressure at the base can be calculated as; Step 3: Determine the spacing of the steel support columns; Step 4: Construction of the layout of the steel support columns. According to the existing basement structure, the steel support columns are arranged layer by layer upward from the basement subgrade to form a three-dimensional support space, so as to realize the reinforcement of the existing basement; Step 5: Arrangement of the steel support jacks. Install steel support jacks at the top of the steel support columns to compensate for the height difference between the steel support columns and the existing basement beams; Step 6: Connection of the support automatic compensation servo system. Connect with the jack through the automatic compensation servo system to realize automatic support compensation; Step 7: Layout of the deformation monitoring points, which are used to monitor the key support parts and the areas prone to deformation in the overall reinforcement area, so as to ensure the safety of the reinforcement area; Step 8: Construction of the horizontal connection of the steel support columns; Step 9: Layout of the structure top plate supports; Step 10: Construction of the concrete slab.

2. The method for reinforcing an existing basement used as a lifting platform for diaphragm walls according to claim 1, wherein: The reinforcement scope in Step 1 needs to be considered according to the whole span of the crawler crane, and the reinforcement area is the walking area of the crawler crane during the construction of the diaphragm wall.

3. A method for strengthening an existing basement used as a lifting platform for diaphragm walls according to claim 1, characterized in that: The steel support columns adopt Q235 Ф609*16mm steel support columns. The spacing of the steel support columns is evenly distributed according to the spacing of the existing structural beam columns, and is designed and distributed according to the total load pressure and the area of the column construction area. At the same time, the quality superposition after the construction of the upper load surface also needs to be considered.

4. A method for strengthening an existing basement used as a lifting platform for diaphragm walls according to claim 1, characterized in that: The existing basement includes the existing structural bottom slab, the existing structural middle slab beam, the existing structural beam and the vertically cast concrete columns. By vertically positioning and arranging the steel support columns between the existing structural bottom slab, the existing structural middle slab beam and the existing structural beam, and the upper and lower steel support columns overlap vertically to ensure the up and down transmission of the load.

5. A method for reinforcing an existing basement used as a lifting platform for diaphragm walls, according to claim 4, characterized in that: The jacks are automatically pressurized. One automatically pressurized jack is installed on each steel support column, and the automatically pressurized jack is arranged at the center position of the column. Through the automatic compensation servo system, the pressure of each group of automatically pressurized jacks is ensured to be the same, ensuring that the multi-point supporting forces of the steel support columns on the existing basement are the same, and automatically compensating for the lost supporting force during use.

6. The method for reinforcing an existing basement used as a lifting platform for diaphragm walls according to claim 4, characterized in that: During the construction process of the layout of the steel support columns, I-beams are installed between multiple steel support columns and between the steel support columns and the concrete columns of the existing basement to ensure the transmission of the horizontal load during the construction of the crawler crane and the overall stability of the support system.

7. A method for reinforcing an existing basement used as a lifting platform for diaphragm walls, according to claim 6, characterized in that: The I-beam and the end of the concrete column are fixed by expansion bolts.

8. The method for reinforcing an existing basement used as a lifting platform for diaphragm walls according to claim 6, characterized in that: Between the I-beam and the steel support column, by welding a connecting steel plate on the steel support column, bolt holes are reserved on the end of the I-beam and the connecting steel plate, and fixed by passing high-strength bolts through the connecting plate and the bolt holes on the I-beam.

9. A method for strengthening an existing basement used as a lifting platform for diaphragm walls, as claimed in claim 1, wherein: At the top of the steel support column at the existing structural beam, a plain bearing plate rubber bearing with a thickness of 100 mm is installed, and then concrete slab construction is carried out on the top of the plain bearing plate rubber bearing.

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