A calculation method for seismic action of narrow-waisted floor

Abstract

The present invention discloses a method for calculating the seismic action of a thin-waisted floor. The method uses the thin-waisted floor as a boundary, defines the structure into three parts: "weak side structure + thin-waisted floor + strong side structure", and obtains the seismic action of each part and each vibration mode through the vibration mode decomposition response spectrum method; only retains the seismic action of the weak side structure, re-performs static analysis, obtains the seismic action effect of each vibration mode of the thin-waisted floor, and performs CQC vibration mode combination to obtain the vibration mode combination seismic action effect of the thin-waisted floor, and then combines it with the effects of other load conditions to obtain the seismic design result of the thin-waisted floor; finally, envelops it with the result of the traditional vibration mode decomposition response spectrum method to obtain the final seismic design result of the thin-waisted floor. The method for calculating the seismic action of the thin-waisted floor of the present invention has few assumptions, can fully reflect the dislocation deformation of the structures on both sides of the thin-waisted floor, stimulates the unfavorable state of the thin-waisted floor, solves the key problems of the current seismic design of the thin-waisted floor, and is easy to promote in engineering.

Description

Technical Field

[0001] The invention relates to the field of building structure engineering design, and in particular to a calculation method for seismic action of a thin-waisted floor. Background Art

[0002] Building structures with waist-shaped floors are commonly found in high-rise and super-high-rise residential buildings. They are widely used in engineering because the waist-shaped plane can better meet the requirements of flexible apartment types, good room permeability, high lighting requirements and high room ratio. Buildings with waist-shaped floor planes are often dumbbell-shaped with a narrow middle and large sides, or multi-limbed (usually three or four limbs) with a vertical traffic core in the middle. The area with a narrower floor in the middle is the waist-shaped floor area. The typical plane forms of such buildings are as follows: Figure 1 , 2 , as shown in Figure 3.

[0003] Buildings with thin waisted floors belong to irregular plane structures in structural design. When the size of the concave and convex on the plane is large, it may cause irregular torsional deformation of the overall structure. Domestic relevant design codes and regulations have given relevant design requirements, such as Article 3.4.3 of the Code for Seismic Design of Buildings (GB 50011-2010) and Articles 3.4.6 to 3.4.7 of the Technical Code for Concrete Structures of High-rise Buildings (JGJ3-2010), which summarize the design concept and construction measures of thin waisted floors. The Technical Points for Special Review of Seismic Fortification of Super-limited High-rise Buildings (Jianzhi

[2015] No. 67) also gives the main scope of super-limited high-rise building projects, and clarifies the irregular concave and convex, combined plane, and discontinuous floor slabs. However, most of them are conceptual regulations and requirements. There is still a lack of more specific guidance on the design of thin waisted floors, and no reasonable regulations and requirements are given for the value of the design internal force of the thin waist part. Therefore, the design of narrow-waisted floor slabs in current actual projects is still flawed. Relevant engineering design analysis also shows that narrow-waisted floor slabs often suffer serious damage in the narrow waist area under major earthquakes, and the shaking table test also shows this.

[0004] The seismic design of building structures is relatively common, and building structures with narrow waisted floors are relatively common in engineering practice, especially in multi-story or high-rise residential structures. However, the seismic design of narrow waisted floors is a weak point in the current seismic design of structures, because the traditional modal decomposition response spectrum method often cannot reflect the displacement deformation of the structures on both sides of the narrow waisted floors. Therefore, it is generally suspected that the seismic internal force of the narrow waisted floors calculated by the modal decomposition response spectrum method is too small, and the current seismic design of structures is unsafe. This displacement deformation should exist in a certain high-order vibration mode of the structure, and its contribution to the seismic response of the entire structure is limited, and it is often difficult to calculate the reverse vibration mode of this displacement deformation. At present, the academic community has proposed some calculation and design methods, which often have many assumptions. For some narrow waisted floor structures, it is often difficult to implement, promote, and apply them in engineering.

[0005] In summary, designers have generally recognized this problem in the seismic design of building structures with thin waisted floors, but there is no good and reasonable solution. It is for this reason that some local regulations, such as the Shenzhen Engineering Construction Standard "Technical Code for Concrete Structures of High-rise Buildings" (SJG98-2021), directly use an amplification factor of 2.0 to directly amplify the seismic internal forces of thin waisted floors. This crude method of directly amplifying internal forces lacks a theoretical basis and is not only uneconomical, but also may pose unsafe risks for some special projects. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a method for calculating the seismic action of a narrow-waisted floor.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for calculating seismic action of a narrow waist floor comprises the following steps:

[0009] (1) Taking the narrow waist floor to be analyzed for earthquake action as the boundary, the building structure is divided into three parts: "weak side structure + narrow waist floor + strong side structure". The side with weaker lateral stiffness of the narrow waist floor is the weak side structure, and the side with stronger lateral stiffness of the narrow waist floor is the strong side structure. The narrow waist floor should be simulated with elastic plate units, and the strong and weak side structures can be elastic plates or rigid plates;

[0010] (2) For the building structure after the sub-tower definition, the modal decomposition response spectrum method is used to analyze the seismic response, and the seismic actions of each modal of the weak side structure and the strong side structure are obtained. The seismic force of each modal of the strong side structure is set to zero, and only the seismic actions of each modal of the weak side structure are retained. Static analysis is performed to obtain the seismic action effects of each modal of the slender floor under the weak side seismic action.

[0011] (3) Considering only the seismic effects of each vibration mode of the slender floor under the weak side earthquake, the CQC vibration mode combination is performed to obtain the vibration mode combination seismic effect of the slender floor, which is then combined with the effects of other load conditions to obtain the seismic design result of the slender floor considering only the weak side earthquake.

[0012] (4) The seismic design results of the slender floor considering only the weak side earthquake action are enveloping the seismic design results of the slender floor using the traditional mode decomposition response spectrum method to obtain the final seismic design results of the slender floor.

[0013] A method for calculating seismic action of a narrow waist floor comprises the following steps:

[0014] S1. Taking the thin waist floor to be analyzed for earthquake action as the boundary, define the building structure into "weak side structure + thin waist floor + strong side structure". The side with weaker lateral stiffness of the thin waist floor is the weak side structure, and the side with stronger lateral stiffness of the thin waist floor is the strong side structure. The thin waist floor should be simulated with elastic plate units, and the strong and weak side structures can use elastic plates or rigid plates;

[0015] S2. Perform modal decomposition response spectrum method earthquake response analysis on the building structure after the sub-tower definition, and obtain the earthquake action of each floor under each modal of the weak side structure and the strong side structure. For the building structure, the horizontal X-direction, horizontal Y-direction, and vertical earthquake action of each floor are respectively , , , where the horizontal X direction is the horizontal direction along the thin waist floor, and the horizontal Y direction is the horizontal direction perpendicular to the thin waist floor. Assuming that The next order vibration mode The horizontal X-direction, horizontal Y-direction and vertical seismic actions of the weak side structure w are , and , the horizontal X-direction, horizontal Y-direction and vertical seismic actions of the strong side structure s are recorded as , and ;

[0016] S3. Set the earthquake action of each vibration mode of the strong side structure to zero, that is, , , , only retain the earthquake action of each vibration mode of the weak side structure , and , conduct static analysis and obtain the The first order vibration Seismic Effects of a Slim Floor ;

[0017] S4. Seismic effects of various vibration modes of thin-waisted floor under weak-side earthquake The CQC vibration mode combination is performed to obtain the first Seismic Effects of a Slim Floor ;

[0018] S5. Set the earthquake action of each vibration mode of the weak side structure to zero, that is, , , , only retain the earthquake effects of each vibration mode of the strong side structure , and , conduct static analysis and obtain the The first order vibration Seismic Effects of a Slim Floor ;

[0019] S6. Seismic effects of various vibration modes of thin-waisted floor under strong lateral earthquake The CQC vibration mode combination is performed to obtain the first Seismic Effects of a Slim Floor ;

[0020] S7, the final envelope is the seismic effect of the thin waist floor, that is, Seismic Effects of a Slim Floor It is expressed as:

[0021] ;

[0022] The seismic effect of the slender floor is combined with the effects under other load conditions to obtain the first load condition under the combination of seismic conditions. Design value of load combination effect of thin-slab floor , so as to carry out seismic design of the slender floor under the corresponding earthquake level; the other load conditions include gravity load conditions and wind load conditions;

[0023] Design values ​​of load combinations considering earthquake conditions To consider the envelope value of each earthquake design combination, that is:

[0024] ;

[0025] in, is the representative value of gravity load under the working condition Shear force of thin waist floor;

[0026] The wind load condition Shear force of thin waist floor;

[0027] In accordance with relevant building structure design specifications Seismic effect of thin-waisted floor , Effects of representative values ​​of gravity loads and the effects of wind loads In the The effect design value of the load combination obtained under the design combination.

[0028] In step S4, the weak side earthquake Seismic Effects of a Slim Floor The calculation is as follows:

[0029] ;

[0030] ;

[0031] in, for Vibration Shape and The coupling coefficient of vibration mode; Calculate the mode number for the structure; , They are Vibration Shape and Damping ratio of the vibration mode; for Vibration Shape and The natural period ratio of the vibration mode; The weak side earthquake The first order vibration The seismic effect of the thin waist floor, The weak side earthquake The first order vibration Seismic effects of a slender floor.

[0032] In step S6, the strong lateral vibration type earthquake Seismic Effects of a Slim Floor The calculation is as follows:

[0033] ;

[0034] in, for Vibration Shape and The coupling coefficient of vibration mode; Calculate the mode number for the structure; The first The first order vibration The seismic effect of the thin waist floor, The first The first order vibration Seismic effects of a slender floor.

[0035] At the same time, the present invention provides:

[0036] A server comprises a processor and a memory, wherein the memory stores at least one program, and the program is loaded and executed by the processor to implement the calculation method of the seismic action of the thin-waisted floor.

[0037] A computer-readable storage medium stores at least one program, which is loaded and executed by a processor to implement the calculation method of the seismic action of the thin-waisted floor.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] 1. When the earthquake action under each vibration mode of the weak side structure and the strong side structure is applied to the structure, the seismic action effect result of the thin waist floor obtained by the method proposed in the present invention is consistent with the result of the traditional vibration mode decomposition response spectrum method. However, the difference of the present invention is that the strong side earthquake action under each vibration mode of the structure is set to zero, and only the earthquake action of each vibration mode of the weak side structure is retained, and the seismic action effect of the thin waist floor is obtained by static analysis. At this time, since there is no earthquake action on the strong side, the deformation of the thin waist floor is fully driven by the weak side structure, and the deformation of the thin waist floor excited by it is more unfavorable than the result when the earthquake action is applied to both the strong side and the weak side structure at the same time, and it can better reflect the unfavorable state of the thin waist floor caused by the dislocation or opposite action of the strong side and weak side structures. Therefore, the present invention is essentially a preset most unfavorable earthquake condition. Compared with the most unfavorable earthquake condition methods such as the forced displacement method (forcing the weak side structure to undergo a specified displacement while the other side of the thin waist floor is fixed) and the multi-point excitation method (the weak side structure base inputs time-history excitation while the other side of the thin waist floor does not input excitation), the calculation assumptions are fewer and it is easier to be accepted by engineering personnel. When the actual project is more complicated, the weak side structure may not be able to be accurately determined. At this time, the structures on both sides of the slender floor can be alternately set as weak side structures, and calculated according to the above method to finally determine the most unfavorable seismic effect of the slender floor, and then carry out subsequent design.

[0040] 2. The weak side earthquake action method proposed in the present invention is directly based on the results of the vibration mode decomposition response spectrum method in obtaining the earthquake action of the thin waist floor, with fewer assumptions and a stronger theoretical basis. Another advantage of this method is that it is consistent with the concerns in current engineering practice, and can fully reflect the displacement deformation and relative deformation of the structures on both sides of the weakly connected floor, solving the key problem of the current seismic design of thin waist floors, and it is also easier to promote the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1This is a typical plan view of a two-limbed (a thin waist) building.

[0042] Figure 2 This is a typical plan view of a three-limb (three thin waist) building.

[0043] Figure 3 This is a typical plan view of a four-limb type (four thin waists) building.

[0044] Figure 4 The figure is a workflow diagram of a method for calculating the seismic action of a narrow-waisted floor.

[0045] Figure 5 This is a schematic diagram of a typical building plan with a narrow floor.

[0046] Figure 6 A schematic diagram of the plane that considers the complex plane on the other side of the slender floor to be analyzed as the strong side.

[0047] Figure 7 Schematic diagram of earthquake action on the weak side structure.

[0048] Figure 8 Schematic diagram of earthquake action applied to both weak-side and strong-side structures.

[0049] Fig. 9 This is a schematic diagram of the situation where no earthquake action is applied to the weak side but earthquake action is applied to the strong side.

[0050] Fig.10 It is a simplified plan view of the model and a schematic diagram of the extracted internal forces of the slender floor.

[0051] Fig.11 To simplify the model, the seismic internal force result diagram of the slender floor under the CQC method and the weak side seismic force method.

[0052] Fig.12 In order to simplify the model, the displacement deformation diagram of the floor slabs on both sides of the slender waist under the weak side earthquake force method is shown.

[0053] Fig.13 This is the plan view of Case 2 and the overall three-dimensional model diagram.

[0054] Fig.14 This is a comparison diagram of the axial force and shear force floor distribution of Case 2 Slim Waist 1.

[0055] Fig.15 This is a comparison diagram of the axial force and shear force floor distribution of Case 2 Slim Waist 2.

[0056] Fig.16 This is a comparison diagram of the axial force and shear force floor distribution of Case 2 Slim Waist 2 before and after replacing the weak side floor slab.

[0057] Fig.17This is the displacement deformation diagram of the floor slabs on both sides of the narrow waist 1 under the Y-direction weak side earthquake force method of the narrow waist 1 in Case 2.

[0058] Fig.18 This is the plan view of Case 3 and the overall three-dimensional model diagram.

[0059] Fig.19 This is a comparison diagram of the axial force and shear force floor distribution of the narrow-waisted floor in Case 3.

[0060] Fig. 20 This is the displacement deformation diagram of the floor slabs on both sides of the thin waist in Case 3 under the X-direction weak side earthquake force method. DETAILED DESCRIPTION

[0061] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0062] The modal decomposition response spectrum method is a method recommended by the code and widely used to calculate the seismic response of various building structures. Based on this method, the patent of this invention proposes a new method for calculating the seismic action of thin waisted floor slabs, which can be used as an effective supplement to the traditional modal decomposition response spectrum method. Figure 4 ,The implementation steps of a calculation method for seismic action of a slender floor are as follows.

[0063] Step 1: Define the structure by towers based on the thin waist floor to be analyzed. Based on the thin waist floor to be analyzed for earthquake action, the thin waist building structure can always be considered as a combination of "weak side + thin waist + strong side". Figure 5 As shown, from the plane, the weak side structure of the slender floor to be analyzed can be defined as a calculation sub-tower separately, and the other side of the slender floor is regarded as the strong side structure and defined as another calculation sub-tower, forming a plane structure form of "weak side + slender waist + strong side".

[0064] The structural plan of the actual project may be more complicated. Figure 6 The figure shows a typical example. The left side of the thin waist floor to be analyzed is a single tower structure, while the right side is a more complex multi-tower structure. At this time, the thin waist floor to be analyzed can still be used as the boundary, and the left side of the floor can be regarded as the weak side structure, and the remaining structure on the right side of the floor can be regarded as the strong side. At this time, the strong side is a combination of multiple structures, and finally a "weak side + thin waist + strong side" plane structure is formed.

[0065] The second step: set the seismic level of the structure, and perform a modal decomposition response spectrum method seismic response analysis on the structure after the sub-tower definition to obtain the seismic actions of each modal mode of the weak-side structure and the strong-side structure. Set the seismic actions of each modal mode of the strong-side structure to zero, and only retain the seismic actions of each modal mode of the weak-side structure. Perform a static analysis to obtain the seismic action effects of each modal mode of the thin-waisted floor under the corresponding seismic level. Figure 7 The weak side structure Schematic diagram of the loading of seismic actions on each layer of the order vibration mode. The seismic actions in the figure include , and , respectively Oscillatory mode The seismic action components in the X direction, Y direction and around the Z direction of the layer.

[0066] When it is impossible to distinguish which side is the strong side and which side is the weak side, it is necessary to take the seismic action of each vibration mode on the weak side as zero for static analysis and envelop the calculation results of the seismic action of each vibration mode on the strong side as zero. If the weak side can be directly determined, this is not necessary. Because the seismic effect of the thin waist floor under the action of only the weak side is usually much greater than the result of the thin waist floor under the action of only the strong side.

[0067] The third step: perform CQC vibration mode combination on the seismic effects of each vibration mode of the slender floor under the weak-side earthquake, obtain the seismic effect of each layer of the slender floor under the weak-side earthquake considering vibration mode coupling, and combine it with the effects under other load conditions, that is, obtain the effect design value of the load combination of each layer of the slender floor under the combination of seismic conditions. These combined load effect values ​​can be used to carry out the seismic design of the slender floor under the corresponding earthquake level.

[0068] Step 4: Envelope the seismic design results of the slender floor under the weak side earthquake obtained in the third step with the traditional slender floor design results based on the vibration mode decomposition response spectrum method.

[0069] Based on the above three steps, the seismic design of the corresponding waisted floor under the weak side earthquake can be obtained. However, since this method is an effective supplement to the traditional modal decomposition response spectrum method, the design results of the waisted floor obtained by it need to be enveloping with the seismic design results of the waisted floor under the traditional modal decomposition response spectrum method. Since the structure is a building structure with a waisted floor, it is necessary to analyze it according to the overall block rigid plate model when executing the traditional modal decomposition response spectrum method, that is, the waisted floor part is analyzed as a non-rigid plate.

[0070] The calculation process of the second and third steps is relatively complicated. It is better to consider only the horizontal earthquake action in the direction perpendicular to the slender floor (Y direction) to solve the seismic shear effect of the slender floor. And obtain the design shear force of the thin waist floor after the corresponding earthquake combination The process is taken as an example, and the specific instructions are as follows:

[0071] 1) Considering a certain design earthquake level, the structure is subjected to a vibration mode decomposition response spectrum method earthquake response analysis to obtain the Y-direction earthquake action of the weak side structure and the strong side structure, such as Figure 8 As shown, the The next order vibration mode The seismic actions of the weak side structure and the strong side structure are respectively expressed as and Set the seismic force of each vibration mode of the strong side structure to zero, that is, take , perform static analysis to obtain the seismic shear force of the narrow waist floor. It represents the first The first vibration mode Seismic shear force of slender floor.

[0072] 2) The seismic shear force of the thin waist floor of each vibration mode under the weak side earthquake is combined by CQC vibration mode, and the seismic shear force of the thin waist floor considering the vibration mode coupling effect is obtained. Seismic shear force of a thin-waisted floor The expression is as follows.

[0073] ;

[0074] ;

[0075] The meanings of the parameters in the above formula are as follows:

[0076] : Vibration Shape and The coupling coefficient of vibration mode;

[0077] : the total number of vibration modes considered;

[0078] , : Vibration Shape and Damping ratio of the vibration mode;

[0079] : Vibration Shape and The natural period ratio of the vibration mode;

[0080] 3) Under normal circumstances, the seismic shear force of the thin waist floor can be obtained by the above formula. However, since the judgment of the weak side structure and the strong side structure is assumed to be subjective, when it is impossible to directly judge which of the two sides of the thin waist is strong or weak, the strong side and the weak side can be swapped, which is equivalent to Fig. 9 As shown in the figure, the weak side earthquake action is set to zero, and only the strong side earthquake action is applied. Static analysis is performed to obtain the The first order vibration The seismic shear force of the thin waist floor can be expressed as , and the thin-waist earthquake shear force considering vibration mode coupling is calculated as follows: .

[0081] ;

[0082] 4) Finally, the seismic shear force obtained under the weak side earthquake action and the strong side earthquake action is enveloping to obtain the Seismic shear force of a thin-waisted floor :

[0083] ;

[0084] Combine the seismic shear force with the representative value of gravity load, the thin waist shear force under wind load and other working conditions according to the code, and obtain the first load combination under the combination of seismic working conditions. Shear force design value of thin waist floor , so as to carry out seismic design of the narrow waist floor under the corresponding earthquake level. Shear design value To consider the envelope of each load combination, namely:

[0085] ;

[0086] The meanings of the parameters in the above formula are as follows:

[0087] : Gravity load representative value condition Shear force of thin waist floor;

[0088] :Under wind load condition Shear force of thin waist floor;

[0089] :According to the relevant building structure design specifications Seismic shear force of thin waist floor , Shear force under representative value of gravity load and shear forces under wind loads In the The combined shear design value obtained from the design combination.

[0090] By adopting the method proposed in the present invention, when the seismic action under each vibration mode of the weak side structure and the strong side structure is applied to the structure, the seismic action effect result of the thin waist floor is consistent with the result of the traditional vibration mode decomposition response spectrum method. However, the difference of the present invention is that the strong side seismic action under each vibration mode of the structure is set to zero, only the seismic action of each vibration mode of the weak side structure is retained, and the seismic action effect of the thin waist floor is obtained by static analysis. At this time, since there is no seismic action on the strong side, the deformation of the thin waist floor is fully driven by the weak side structure. The deformation of the thin waist floor stimulated by it is more unfavorable than the result of applying seismic action to both the strong side and the weak side structures at the same time (traditional vibration mode decomposition response spectrum method), and it can better reflect the unfavorable state of the thin waist floor caused by the dislocation or opposite action of the strong side and weak side structures. Therefore, the present invention is essentially a preset most unfavorable earthquake condition. Compared with the most unfavorable earthquake condition methods such as the forced displacement method (forcing the weak side structure to undergo a specified displacement while the other side of the thin waist floor is fixed) and the multi-point excitation method (the weak side structure base inputs time-history excitation while the other side of the thin waist floor does not input excitation), the calculation assumptions are fewer and it is easier to be accepted by engineering personnel. When the actual project is more complicated, the weak side structure may not be accurately determined. At this time, the structures on both sides of the thin waist floor can be alternately set as the weak side structure, and the calculation is performed according to the above method to finally determine the most unfavorable earthquake effect of the thin waist floor, and then carry out subsequent design.

[0091] The method proposed in the present invention is directly based on the results of the vibration mode decomposition response spectrum method in obtaining the seismic action of the thin waist floor, with fewer assumptions and a stronger theoretical basis. Another advantage of this method is that it is consistent with the concerns in current engineering practice, and can fully reflect the displacement deformation and relative deformation of the structures on both sides of the weakly connected floor, solving the key problem of the current seismic design of thin waist floor, and it is also easier to promote the project.

[0092] In order to fully illustrate the effect of the method proposed in the patent of this invention in calculating the seismic effect of a thin waisted floor in a building structure with a thin waisted floor, three cases are used for illustration. For the convenience of description, in the subsequent actual case comparison process, the method of this patent is referred to as the "weak side seismic force method". The three cases are a simplified case and two actual engineering cases, respectively. The results of the "weak side seismic force method" proposed in this patent and the traditional vibration mode decomposition response spectrum method, that is, the CQC method, are compared. At the same time, the lateral deformation morphology of the structure under the action of the patent method is also observed to illustrate that it can reflect the dislocation deformation of the structures on both sides of the thin waisted floor and stimulate the unfavorable state of the thin waisted floor.

[0093] (1) Case 1: Simplified model.

[0094] The simplified model takes a frame structure with nine-square planes on both sides, a standard span of 6mx6m, and a 1x2 span waist in the middle as the waist floor to be analyzed. There is no ground vertical structure within the waist floor, the floor height is 3.6m, and the total number of floors is 15. It is a symmetrical waist model. The plane is as follows Fig.10 shown.

[0095] The cross-sections of the model beams and columns are 300mmx600mm and 600mmx600mm respectively, the floor slab is 150mm thick, and the additional constant liveness of the floor slab is 2kPa and 4kPa respectively. Considering 7-degree (0.1g) fortification, the second design grouping, site category II, characteristic period 0.4s, damping ratio 5%, period reduction is not considered for the time being, and elastic analysis is performed according to multiple earthquakes.

[0096] The block rigid plate model is used to perform traditional modal decomposition response spectrum method (CQC method) and the “weak side seismic force method” proposed in this paper to extract the axial force and shear force of the thin waist section for comparison. The axial force of the thin waist section is perpendicular to the thin waist cross section, and the thin waist shear force is along the cross section direction. Both are forces within the thin waist surface.

[0097] The axial force and shear force results of the narrow waist floor under the two methods are as follows Fig.11 The internal force distribution results of each layer under the “weak side earthquake force method” are greater than those under the CQC method. This internal force distribution result is consistent with the expected structural displacement deformation characteristics on both sides of the thin waist floor, as shown in Fig.12 shown.

[0098] (2) Case 2: Actual project with multiple limbs.

[0099] This case is a super high-rise residential and commercial building with a shear wall structure system. According to the Technical Code for Concrete Structures of High-Rise Buildings (JGJ3-2010) [JGJ3-2010 Technical Code for Concrete Structures of High-Rise Buildings [S]. Beijing: China Architecture & Building Press, 2010.], the small earthquake elastic design is carried out, with a 7-degree (0.1g) seismic fortification, the first design group, the site category is Class II, the characteristic period is 0.35s, the damping ratio is 5%, the period reduction factor is 0.95, and the number of vibration modes is 30. The standard residential floor height is 3.0m, the total building height is 138.9m, and the structural model is as follows: Fig.13 As shown, there are two thin waists on the plane of this case, which are marked as thin waist 1 and thin waist 2 respectively. In this case, the floor slabs of the two refuge floors on the 11th and 27th floors and the roof layer are pulled through to avoid the thin waists.

[0100] The floor distribution comparison of axial force and shear force of waist 1 and waist 2 under small earthquake elasticity in this case under CQC method and "weak side earthquake force method" is as follows Fig.14 , 15As shown (since the waist-length of the slab is not formed by pulling through the layer, the value of the corresponding curve segment in the figure is zero). It can be seen that the overall distribution trend of the axial force and shear force of the waist 1 under the "weak side seismic force method" is close to that of CQC. For individual floors, such as the top floor and floors close to the refuge floor where the slab passes through, the results of the CQC method will exceed those of the "weak side seismic force method". For most floors, the results of the "weak side seismic force method" will exceed those of the CQC method. Therefore, this also explains to a certain extent that the "weak side seismic force method" proposed in this patent can effectively stimulate the adverse deformation of the structure on both sides of the waist and ensure the safety of the structure under earthquake.

[0101] By comparing the internal force distribution of Slender Waist 2, it is found that the overall distribution trend of the axial force and shear force of Slender Waist 2 under the "weak side seismic force method" is also relatively close to that of CQC. The axial force value of Slender Waist 2 under the weak side seismic force method is also greater than the result of CQC method. However, in the shear force distribution of Slender Waist 2, it is obvious that most floors under the "weak side seismic force method" are lower than the result of CQC method. The reason is that when loading in the X direction, the X-direction stiffness of the middle core tube is large, and the side where it is located should be regarded as the strong side. The weak side floor needs to be replaced (that is, the vibration type seismic force of the weak side floor is set to zero and the vibration type seismic force of the original strong side floor is maintained), and the axial force and shear force of the Slender Waist under the "weak side seismic force method" are recalculated. Comparison results Fig.16 At this time, the shear force of the thin waist 2 under the "weak side earthquake force method" is significantly increased compared with before the replacement, and most floors are greater than the results of the CQC method, while the thin waist axial force is reduced compared with before the replacement, but it is still greater than the results of the CQC method as a whole.

[0102] Therefore, in actual engineering, when the plane stiffness of the two sides of the thin waist is similar (or difficult to judge intuitively), it is necessary to consider replacing the weak side floor slab and perform the "weak side seismic force method" calculation respectively, and take the thin waist internal force envelope value for subsequent analysis or design. This is exactly why the aforementioned invention content of this patent clearly suggests replacing the strong side and the weak side when executing the steps of the method proposed in this patent, and also considers that the weak side does not apply seismic force but the strong side applies seismic force.

[0103] In reflecting the displacement deformation of the weak side floor, the lateral deformation result of the thin waist 1 under the Y-direction weak side earthquake force loading is taken as follows: Fig.17 As shown in the figure, it is obvious that the stairs on both sides of the waist 1 underwent significant displacement and deformation under the action of the weak side earthquake force.

[0104] (3) Case 3: An actual project with a podium at the bottom and a weak-side setback at the top.

[0105] This case is a super high-rise residential building and apartment, which is a shear wall structure system. According to the Guangdong Provincial Standard "Technical Code for Concrete Structure of High-rise Buildings" (DBJ 15-92-2021) [DBJ / T 15-92-2021 Technical Code for Concrete Structure of High-rise Buildings [S]. Beijing: China Urban Press, 2021.], the moderate earthquake design is carried out, with a 7-degree (0.1g) seismic fortification, the first design group, the site category is Class II, the characteristic period is 0.35s, the damping ratio is 5.5%, and the period reduction is not considered. The number of vibration modes is 30. The standard floor height of the structure is 3.3m, the total number of floors is 44, the structural roof elevation is 148.65m, and the structural model diagram is as follows Fig.18 As shown, one side of the weak side floor slab is retracted 5 floors in advance at the top.

[0106] This case is a moderate earthquake design. The floor distribution comparison of the axial force and shear force of the thin waist under the CQC method and the "weak side earthquake force method" is as follows: Fig.19 As shown. The law is similar to the result of Case 2. The overall distribution trend of the thin waist internal force obtained by the two methods is consistent. The "weak side seismic force method" is higher than the CQC method for most floors. For the bottom skirt floor and the top weak side setback floor, the "weak side seismic force method" cannot reflect the influence of the strong side on the weak side, so the thin waist internal force is lower than the CQC method result. This is because the concept of the thin waist floor is weak in the bottom skirt floor and the top weak side setback floor. On the contrary, the CQC method can reflect the impact of the floor seismic force change caused by the sudden setback of the entire floor.

[0107] In reflecting the displacement deformation of the weak side floor, the lateral deformation result of the thin waist floor under the X-direction weak side earthquake force loading is taken, as shown in Fig. 20 As shown in the figure, it is obvious that the stairs on both sides of the slender floor have undergone significant displacement and deformation under the action of the weak side earthquake force.

[0108] In summary: for the seismic design of building structures with thin-waisted floors, considering the defects and shortcomings of existing seismic design methods, the present invention proposes a new calculation method for the seismic action of thin-waisted floors: the weak side seismic force method, as an effective supplement to the traditional vibration mode decomposition response spectrum method.

[0109] Since the traditional modal decomposition response spectrum method is very mature in engineering applications, the seismic design of domestic building structures basically adopts this method, and the seismic design software of building structures on the market has embedded this method. The present invention, like the traditional modal decomposition response spectrum method, also needs to perform modal decomposition response spectrum analysis of the structure first to obtain the seismic action of the structure under each order of vibration mode, which is very familiar to structural designers and widely accepted.

[0110] However, unlike the traditional modal decomposition response spectrum method, this method requires designers to first divide the thin waisted building structure into "weak side structure + thin waisted floor + strong side structure", so that after executing the modal decomposition response spectrum method, the seismic action of each vibration mode of the strong side structure and the weak side structure can be obtained, and the seismic action of the weak side structure is retained, and the other seismic actions are set to zero, and static analysis is performed separately to obtain the seismic action effects of each vibration mode of the thin waisted floor. This is also easy to understand for structural designers. They only need to define a load condition for the weak side seismic action under each vibration mode in the existing software for static analysis, which is also easy to implement using existing design software.

[0111] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for calculating the seismic action of a narrow waist floor, characterized in that: The following steps are involved: (1) Taking the slender floor to be analyzed as the boundary, the building structure is divided into three parts: "weak side structure + slender floor + strong side structure". The side with weaker lateral stiffness of the slender floor is the weak side structure, and the side with stronger lateral stiffness of the slender floor is the strong side structure. The slender floor is simulated by elastic plate elements, and the strong and weak side structures are simulated by elastic plates or rigid plates. (2) After the sub-towers are defined, the earthquake response analysis of the building structure using the modal decomposition response spectrum method is performed to obtain the earthquake actions of each modal mode of the weak side structure and the strong side structure; The earthquake effects of each vibration mode of the strong side structure are set to zero, and only the earthquake effects of each vibration mode of the weak side structure are retained. The static analysis is re-performed to obtain the earthquake effects of each vibration mode of the thin waist floor under the consideration of only the weak side earthquake action. (3) Considering only the seismic effects of each vibration mode of the slender floor under the weak side earthquake, the CQC vibration mode combination is performed to obtain the vibration mode combination seismic effect of the slender floor, which is then combined with the effects of other load conditions to obtain the seismic design result of the slender floor considering only the weak side earthquake. (4) The seismic design results of the slender floor considering only the weak side earthquake action are enveloping the seismic design results of the slender floor using the traditional mode decomposition response spectrum method to obtain the final seismic design results of the slender floor.

2. A method for calculating the seismic action of a narrow waist floor, characterized in that: The following steps are involved: S1. Taking the thin waist floor to be analyzed for earthquake action as the boundary, the building structure is divided into three parts: "weak side structure + thin waist floor + strong side structure". The side of the thin waist floor with weaker lateral stiffness is the weak side structure, and the side of the thin waist floor with stronger lateral stiffness is the strong side structure; the thin waist floor is simulated by elastic plate unit, and the strong side structure and weak side structure are simulated by elastic plate or rigid plate; S2. Perform modal decomposition response spectrum method earthquake response analysis on the building structure after the sub-tower definition, and obtain the earthquake action of each floor under each modal of the weak side structure and the strong side structure; For the building structure, the earthquake actions in the horizontal X direction, horizontal Y direction, and vertical direction of each floor are , , , where the horizontal X direction is the horizontal direction along the thin waist floor, and the horizontal Y direction is the horizontal direction perpendicular to the thin waist floor. Assuming that The next order vibration mode The horizontal X-direction, horizontal Y-direction and vertical seismic action of the weak side structure w are recorded as , and , the horizontal X-direction, horizontal Y-direction and vertical seismic actions of the strong side structure s are recorded as , and ; S3. Set the earthquake action of each vibration mode of the strong side structure to zero, that is, , , , only retain the earthquake action of each vibration mode of the weak side structure , and , conduct static analysis and obtain the The first order vibration Seismic Effects of Slender Floors ; For the narrow-waisted floor, the earthquake effect includes the in-plane shear force, axial force and bending moment of the narrow-waisted floor; S4. Seismic effects of various vibration modes of thin-waisted floor under weak-side earthquake The CQC vibration mode combination is performed to obtain the first Seismic Effects of Slender Floors ; S5. Set the earthquake action of each vibration mode of the weak side structure to zero, that is, , , , only retain the earthquake effects of each vibration mode of the strong side structure , and , conduct static analysis and obtain the The first order vibration Seismic Effects of Slender Floors ; S6. Seismic effects of various vibration modes of thin-waisted floor under strong lateral earthquake The CQC vibration mode combination is performed to obtain the first Seismic Effects of Slender Floors ; S7, the final envelope is the seismic effect of the thin waist floor, that is, Seismic Effects of Slender Floors It is expressed as: ； The seismic effect of the slender floor is combined with the effects under other load conditions to obtain the first load condition under the combination of seismic conditions. Design value of load combination effect of thin-slab floor , so as to carry out seismic design of the slender floor under the corresponding earthquake level; the other load conditions include gravity load conditions and wind load conditions; Design values ​​of load combinations considering earthquake conditions To consider the envelope value of each earthquake condition combination, that is: ； in, is the representative value of gravity load under the working condition The effect of a thin waist floor; For wind load condition The effect of a thin waist floor; In accordance with relevant building structure design specifications Seismic effect of thin-waisted floor , Effects of representative values ​​of gravity loads and the effects of wind loads In the The effect design value of the load combination obtained by the design combination.

3. The calculation method of seismic action of a narrow waist floor according to claim 2 is characterized in that: In step S4, the weak side earthquake Seismic Effects of Slender Floors The calculation is as follows: ； ； in, for Vibration Shape and The coupling coefficient of vibration mode; Calculate the mode number for the structure; , They are Vibration Shape and Damping ratio of the vibration mode; for Vibration Shape and The natural period ratio of the vibration mode; The weak side earthquake The first order vibration The seismic effect of the thin waist floor, The weak side earthquake The first order vibration Seismic effects of a slender floor.

4. The method for calculating the seismic action of a narrow waisted floor according to claim 2 is characterized in that: In step S6, the strong side earthquake Seismic Effects of Slender Floors The calculation is as follows: ； in, for Vibration Shape and The coupling coefficient of vibration mode; Calculate the mode number for the structure; The first The first order vibration The seismic effect of the thin waist floor, The first The first order vibration Seismic effects of a slender floor.

5. A server, comprising a processor and a memory, characterized in that: At least one program is stored in the memory, and the program is loaded and executed by the processor to implement the method for calculating the seismic action of the narrow-waisted floor as claimed in any one of claims 1 to 4.

6. A computer-readable storage medium, wherein at least one program is stored in the storage medium, characterized in that: The program is loaded and executed by a processor to implement the calculation method of the seismic action of the slender floor as claimed in any one of claims 1 to 4.

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