A judgment method based on the reverse reinforcement construction of mid-rise buildings

Abstract

The present invention aims to provide a method for judging the safety of the reverse reinforcement construction structure of a mid-rise building through the axial compression ratio. The present invention checks the degree of damage to the building structure components; establishes an axial force calculation model for the vertical load-bearing components of vacant buildings, and confirms the axial compression ratio q1 of the vacant vertical load-bearing components; checks the fortification intensity of the area where the building is located, and determines the reinforcement method of the building structure based on the axial compression ratio q1 of the vacant vertical load-bearing components; confirms the maximum vacancy ratio, S1, based on the preferred axial compression ratio of the frame columns and frame shear walls of the fortification intensity of the area where the building is located; calculates the number of vacant floors based on the maximum vacancy ratio S1, and performs demolition and reinforcement operations. The present invention is applied to the technical field of the judgment method of the reverse reinforcement construction of mid-rise buildings.

Description

Technical Field

[0001] The present invention relates to the technical field of a method for judging the reverse reinforcement construction of a middle-rise building, and in particular to a method for judging the reverse reinforcement construction of a middle-rise building. Background Art

[0002] As a lifeline project to protect people's personal safety, hospital buildings undertake the important mission of emergency rescue and medical assistance after disasters. Therefore, they are required to continue to be used in the event of a large-scale earthquake, or to be quickly restored after the disaster. Their earthquake resistance and disaster prevention capabilities directly affect the safety of the urban system and social stability. Therefore, the demand for renovation and reinforcement of hospital buildings has increased in recent years.

[0003] The conventional reinforcement process requires the entire building to be vacated, and the reinforcement order is from bottom to top, that is, from the ground floor to the top floor, layer by layer. However, due to business needs, some hospital outpatient or inpatient buildings cannot be vacated as a whole. Therefore, some floors will be vacated and reinforced, and some floors will need to operate normally. In consideration of the convenience of business development, the top floor will be vacated and reinforced first, and the bottom floor will be reinforced later, that is, the reinforcement order is changed from top to bottom. The structure of the building to be reinforced is relatively fragile. The construction waste and construction materials accumulated during the top reinforcement process will increase the burden on the original vertical load-bearing components below, and their safety is difficult to guarantee. Therefore, it is necessary to control the proportion of vacated floors in the building to ensure the safety of the lower vertical load-bearing components before reinforcement. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for judging the safety of a middle-rise building reinforced construction structure by a reverse construction method through an axial compression ratio.

[0005] The technical solution adopted by the present invention is: the determination method of the present invention comprises the following steps:

[0006] S1. Check the damage degree of building structural components;

[0007] S2. Establish an axial force calculation model for vertical load-bearing components of vacant buildings and confirm the axial compression ratio q1 of vacant vertical load-bearing components;

[0008] S3. Check the fortification intensity of the area where the building is located, and determine the building structure reinforcement method based on the axial compression ratio q1 of the vacant vertical load-bearing components;

[0009] S4. Determine the maximum vacancy ratio S1 based on the preferred axial compression ratio of the frame columns and frame shear walls of the building's design intensity in the area where the building is located;

[0010] S5. Calculate the number of vacant floors based on the maximum vacant ratio S1 and carry out demolition and reinforcement operations.

[0011] Further, in step S2, the calculation formula for the axial force of the vertical load-bearing components of the vacant building is:

[0012] N=X[q*A*fc*(mn) / m+0.7*q*A*fc*n / m];

[0013] Vacancy ratio s = n / m

[0014] Axial compression ratio of vacant vertical load-bearing members q1 = N / (A*fc) = X(1-0.3s)q;

[0015] Where N is the axial force of the vertical load-bearing member of the structure, X is the structural importance coefficient, q is the axial compression ratio of the vertical load-bearing member, A is the area, fc is the concrete strength, s is the vacant ratio, m is the total number of floors of the building structure, and n is the number of vacant floors.

[0016] Furthermore, the structural importance coefficient X is taken as 0.9.

[0017] Further, in step S3, determining the building structure reinforcement method includes the following steps:

[0018] S3.1. Select areas with regional fortification intensity of 6, 7 and 8 degrees. If the regional intensity does not belong to the above fortification intensity range, the bottom-up reinforcement method shall be adopted;

[0019] S3.2. Based on the axial compression ratio q1 of the vacant vertical load-bearing components, select the optimal axial compression ratio of the frame structure and scissor wall structure of the building's design intensity, and calculate the axial compression ratio q1 of the vacant vertical load-bearing components;

[0020] S3.3. If the axial compression ratio q1 of the vacant vertical load-bearing member is less than 1, the reverse reinforcement method is selected. If the axial compression ratio q1 of the vacant vertical load-bearing member is greater than 1, the bottom-to-top reinforcement method is adopted.

[0021] Further, in step S5, the demolition and reinforcement operation includes the following steps:

[0022] S5.1. For the demolition and reinforcement work of vacant floors, after the reinforcement of vacant floors is completed, the reinforcement acceptance shall be carried out;

[0023] S5.2. After the vertical load-bearing components are reinforced, the remaining floors are demolished and reinforced, and then the upper floors that have been reinforced are decorated and built;

[0024] S5.3. Inspect and accept the overall building structural components.

[0025] The beneficial effects of the present invention are as follows: since the present invention adopts the optimal axial compression ratio of the frame structure and the scissor wall structure of the fortification intensity of the area where the building is located to judge the reinforcement method of the building, by confirming the structural vacancy ratio of different structural systems with different fortification intensities of the maximum axial compression ratio of the frame structure and the scissor wall structure, the safety of the reverse reinforcement operation is ensured. The reverse reinforcement method can reduce the downtime of the hospital building by about 30% during the reinforcement process, and effectively reduce the impact of the reinforcement project on the hospital operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the reverse operation judgment method of the present invention. DETAILED DESCRIPTION

[0027] like Figure 1 As shown, in this embodiment, the determination method of the present invention includes the following steps:

[0028] S1. Check the damage degree of building structural components;

[0029] S2. Establish an axial force calculation model for vertical load-bearing components of vacant buildings and confirm the axial compression ratio q1 of vacant vertical load-bearing components;

[0030] S3. Check the fortification intensity of the area where the building is located, and determine the building structure reinforcement method based on the axial compression ratio q1 of the vacant vertical load-bearing components;

[0031] S4. Determine the maximum vacancy ratio S1 based on the preferred axial compression ratio of the frame columns and frame shear walls of the building's design intensity in the area where the building is located;

[0032] S5. Calculate the number of vacant floors based on the maximum vacant ratio S1 and carry out demolition and reinforcement operations.

[0033] In this embodiment, in step S2, the calculation formula for the axial force of the vertical load-bearing components of the vacant building is:

[0034] N=X[q*A*fc*(mn) / m+0.7*q*A*fc*n / m];

[0035] Vacancy ratio s = n / m

[0036] Axial compression ratio of vacant vertical load-bearing members q1 = N / (A*fc) = X(1-0.3s)q;

[0037] Where N is the axial force of the vertical load-bearing member of the structure, X is the structural importance coefficient, q is the axial compression ratio of the vertical load-bearing member, A is the area, fc is the concrete strength, s is the vacant ratio, m is the total number of floors of the building structure, and n is the number of vacant floors;

[0038] The vacancy ratio is s = n / m. At present, the unit area gravity caused by dead load and live load in domestic reinforced concrete high-rise buildings is about 12kN / m for frame and frame-shear wall structures. 2 ~14kN / m 2 , shear wall and cylinder structure are about 13kN / m 2 ~16kN / m 2 , and the live load is about 2kN / m 2 ~3kN / m 2 [Explanation of Article 5.1.8 of Technical Code for Concrete Structures of High-Rise Buildings JGJ 3-2010];

[0039] Therefore, the deadweight of the structure is assumed to be approximately 9 kN / m 2 , using live load of 2.5kN / m 2 , construction live load is 1kN / m 2 The standard combination formula of concrete structure load is Q = 1.2G + 1.5Qg + Qr, where Q is the combined load of the concrete structure, G is the static load, Qg is the endurance load, and Qr is the variable load;

[0040] Standard combination of structural loads in vacant state Q1 = (1*9+1*1) / (1*12+1*2.5) = 0.69

[0041] Basic combination Q2 in vacant state = (1.3*9+1.5*1) / (1.3*12+1.5*2.5) = 0.68

[0042] Therefore, the vacant floor load can be set to 0.7 times the original load.

[0043] In this embodiment, the structural importance coefficient X is taken as 0.9, in accordance with 4.2.3 of the Steel Structure Engineering Construction Code.

[0044] In this embodiment, in step S3, determining the building structure reinforcement method includes the following steps:

[0045] S3.1. Select areas with regional fortification intensity of 6, 7 and 8 degrees. If the regional intensity does not belong to the above fortification intensity range, the bottom-up reinforcement method shall be adopted;

[0046] S3.2. Based on the axial compression ratio q1 of the vacant vertical load-bearing components, select the optimal axial compression ratio of the frame structure and scissor wall structure of the building's design intensity, and calculate the axial compression ratio q1 of the vacant vertical load-bearing components;

[0047] S3.3. If the axial compression ratio q1 of the vacant vertical load-bearing member is less than 1, the reverse reinforcement method is selected; if the axial compression ratio q1 of the vacant vertical load-bearing member is greater than 1, the bottom-to-top reinforcement method is adopted;

[0048] In step S3.1, based on the fortification intensity of the selected area and combined with the contents of Table 6.4.2 and Table 7.2.13 in the Technical Code for Concrete Structures of High-rise Buildings, a comparison table of fortification intensity axial compression ratio is formed:

[0049]

[0050]

[0051] The axial compression ratio of the vertical load-bearing components after being vacant q1 = X(1-0.3s)q must meet the requirements of the axial compression ratio comparison table of the design intensity;

[0052] When the whole building is vacant, that is, S=1, the axial compression ratio of the vertical load-bearing components is 0.9(1-0.3*1)q=0.63q. When 0.63q does not meet the requirements of the axial compression ratio comparison table of the design intensity, it indicates that the building structure also has certain risks under the no-load state, and the traditional method should be adopted to strengthen the whole building from bottom to top.

[0053] According to the axial compression ratio of vacant vertical load-bearing components q1=X(1-0.3s)q combined with the design intensity axial compression ratio comparison table, the optimal axial compression ratio comparison table of the design intensity frame columns and frame shear walls is comprehensively formed:

[0054]

[0055] In the comparison table of the ultimate axial compression ratios of columns and walls that can be reinforced by the reverse construction method, the maximum axial compression ratio of the hospital building columns in the 6-degree area is greater than 1.2, and the maximum axial compression ratio of the shear wall is greater than 0.85; the maximum axial compression ratio of the hospital building columns in the 7-degree area is greater than 1.1, and the maximum axial compression ratio of the shear wall is greater than 0.8; the maximum axial compression ratio of the hospital building columns in the 8-degree area is greater than 1, and the maximum axial compression ratio of the shear wall is greater than 0.6. It is not suitable to use the reverse construction method to complete the reinforcement work, and it is advisable to reinforce the whole building according to the traditional reinforcement method;

[0056] Based on the optimal axial compression ratio comparison table of the design intensity frame columns and frame shear walls, combined with the value range of the axial compression ratio q of the vertical load-bearing components, the maximum vacancy ratio comparison table is obtained:

[0057]

[0058] Confirm the maximum vacancy ratio S1 of the building reinforced by reverse construction method.

[0059] In this embodiment, in step S5, the demolition and reinforcement operation includes the following steps:

[0060] S5.1. For the demolition and reinforcement work of vacant floors, after the reinforcement of vacant floors is completed, the reinforcement acceptance shall be carried out;

[0061] S5.2. After the vertical load-bearing components are reinforced, the remaining floors are demolished and reinforced, and then the upper floors that have been reinforced are decorated and built;

[0062] S5.3. Inspect and accept the overall building structural components.

[0063] In this embodiment, the frame-shear shear wall structure has 13 floors above ground and 2 floors underground, a total of 15 floors, a height of 46.4m, and a seismic fortification intensity of 7 degrees 0.1g. The reinforcement process is based on the reverse method;

[0064] The first step is to determine the damage status of the entire building structure. The appraisal report shows that there is no obvious damage to the foundation and the upper structure, so the reverse reinforcement method can be considered;

[0065] The second step is to find the maximum axial compression ratio of the frame column and the shear wall in the identification model. In the identification model, the maximum axial compression ratio of the frame column appears in the middle column of the underground first floor, the maximum axial compression ratio is 1.19, the cross section is 800*700, and the concrete strength grade is C28. The maximum axial compression ratio of the shear wall appears on the first floor, the maximum axial compression ratio is 0.45, the wall thickness is 250, and the concrete strength grade is C28. The maximum axial compression ratio of the frame column is the controlled axial compression ratio. Calculate the axial compression ratio q1 of the vacant vertical load-bearing member;

[0066] The third step is to combine the comparison table of the optimal axial compression ratio of the frame columns and frame shear walls of the design intensity to determine whether the structure can be reinforced by the reverse method;

[0067] Step 4: According to the maximum vacancy ratio comparison table, the vacancy ratio of this project is 50%, and there are 8 vacant floors;

[0068] The fifth step is to dismantle and reinforce the vacant floors. After the reinforcement of the vacant floors is completed, the reinforcement acceptance will be carried out. Dismantle and reinforce the remaining floors. After the reinforcement of the vertical load-bearing components is completed, the decoration and masonry work will be carried out on the upper floors that have been reinforced.

[0069] Although the embodiments of the present invention are described with practical solutions, they do not constitute limitations on the meaning of the present invention. For those skilled in the art, it is obvious to modify the implementation scheme and combine it with other solutions based on this description.

Claims

1. A judgment method based on the reverse reinforcement construction of a mid-rise building, characterized in that: The determination method comprises the following steps: S1. Check the damage degree of building structural components; S2. Establish an axial force calculation model for vertical load-bearing components of vacant buildings and confirm the axial compression ratio q1 of vacant vertical load-bearing components; S3. Check the fortification intensity of the area where the building is located, and determine the building structure reinforcement method based on the axial compression ratio q1 of the vacant vertical load-bearing components; S4. Determine the maximum vacancy ratio S1 based on the preferred axial compression ratio of the frame columns and frame shear walls of the building's design intensity in the area where the building is located; S5. Calculate the number of vacant floors based on the maximum vacant ratio S1 and carry out demolition and reinforcement operations; In step S2, the calculation formula for the axial force of the vertical load-bearing components of the vacant building is: N=X[q*A*fc*(mn) / m+0.7*q*A*fc*n / m]; Vacancy ratio s = n / m Axial compression ratio of vacant vertical load-bearing members q1 = N / (A*fc) = X(1-0.3s)q; Where N is the axial force of the vertical load-bearing member of the structure, X is the structural importance coefficient, q is the axial compression ratio of the vertical load-bearing member, A is the area, fc is the concrete strength, s is the vacant ratio, m is the total number of floors of the building structure, and n is the number of vacant floors; In step S3, determining the building structure reinforcement method includes the following steps: S3.

1. Select areas with regional fortification intensity of 6, 7 and 8 degrees. If the regional intensity does not belong to the above fortification intensity range, the bottom-up reinforcement method shall be adopted; S3.

2. Based on the axial compression ratio q1 of the vacant vertical load-bearing components, select the optimal axial compression ratio of the frame structure and scissor wall structure of the building's design intensity, and calculate the axial compression ratio q1 of the vacant vertical load-bearing components; S3.

3. If the axial compression ratio q1 of the vacant vertical load-bearing member is less than 1, the reverse reinforcement method is selected. If the axial compression ratio q1 of the vacant vertical load-bearing member is greater than 1, the bottom-to-top reinforcement method is adopted.

2. The judgment method based on the top-down reinforcement construction of a mid-rise building according to claim 1 is characterized in that: The structural importance coefficient X is taken as 0.

9.

3. The judgment method based on the top-down reinforcement construction of a mid-rise building according to claim 1 is characterized in that: In step S5, the demolition and reinforcement operation includes the following steps: S5.

1. For the demolition and reinforcement work of vacant floors, after the reinforcement of vacant floors is completed, the reinforcement acceptance shall be carried out; S5.

2. After the vertical load-bearing components are reinforced, the remaining floors are demolished and reinforced, and then the upper floors that have been reinforced are decorated and built; S5.

3. Inspect and accept the overall building structural components.

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