Design method of masonry structures strengthened with ductile cementitious composite based on ductility

Abstract

This invention provides a design method for reinforcing masonry structures with high-ductility cement-based composite materials based on toughness, comprising the following steps: assessing the seismic toughness level of the existing masonry structure to determine the seismic toughness improvement target; preliminarily determining the design parameters of the high-ductility cement-based composite material surface layer based on the seismic toughness improvement target; assessing the seismic toughness level of the reinforced masonry structure to confirm whether the seismic toughness improvement target is met, and obtaining the design parameters of the high-ductility cement-based composite material surface layer that meet the seismic toughness improvement target based on the confirmation result. The beneficial effects of this invention are: this invention organically combines the quantification of seismic toughness with the reinforcement design scheme, and uses a new high-performance material to establish a reinforcement design method for existing masonry structures to improve the seismic toughness level of existing masonry structures. Therefore, this invention not only considers the improvement of the seismic performance of existing masonry structures, but also the optimization of structural repair time and repair costs.

Description

Technical Field

[0001] This invention relates to the field of seismic reinforcement technology for building structures, and in particular to a design method for reinforcing masonry structures with high-ductility cement-based composite materials based on toughness. Background Technology

[0002] my country still has a large number of masonry structures built in the 1980s and 1990s, such as residences, schools, and hospitals. These structures generally suffer from low material strength and poor overall integrity. When reviewed according to current seismic codes, the seismic bearing capacity and deformation capacity of these buildings are often severely inadequate. In the event of a fortified earthquake or a rare earthquake, existing masonry structures are prone to brittle shear failure and overall collapse, causing significant loss of life and property. Therefore, safe, effective, and economical seismic reinforcement of existing masonry structures is an urgent need and an important research direction in the field of civil engineering.

[0003] Current seismic strengthening design methods for masonry structures aim to improve the structure's load-bearing capacity, stiffness, and / or ductility, primarily focusing on the structure's epicentral behavior (strength, deformation) and post-earthquake state (damage level). Commonly used strengthening materials include reinforced concrete mesh mortar layers, concrete slab walls, and fiber-reinforced composite materials. While these methods improve structural safety to some extent, their design basis is largely focused on ensuring life safety and controlling structural seismic losses, neglecting the post-earthquake functional recovery phase—that is, the time and cost of functional repair after an earthquake. In this context, while some strengthening schemes achieve damage control goals, post-earthquake repair is difficult, time-consuming, and costly, resulting in excessively long functional recovery periods and causing serious economic and social impacts. In other words, existing methods lack a systematic assessment and design guidance for the overall "toughness" of the strengthened structure. Therefore, there is an urgent need to develop a design method suitable for strengthening masonry structures using new high-performance materials, with quantitative toughness assessment as the core objective and design basis. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a design method for reinforcing masonry structures based on toughness-based high-ductility cement-based composite materials, which solves the problem that although existing reinforcement schemes achieve damage control targets, post-earthquake repair is difficult, time-consuming and costly, resulting in excessively long functional recovery cycles and causing serious economic and social impacts.

[0005] To achieve the above and other related objectives, the present invention provides the following technical solution:

[0006] A design method for reinforcing masonry structures with high-ductility cement-based composite materials based on toughness is disclosed. The method includes the following steps: obtaining basic information of the existing masonry structure to be reinforced; constructing a finite element model of the existing masonry structure based on the basic information; evaluating the seismic toughness level of the existing masonry structure based on the finite element model; determining the seismic toughness improvement target of the existing masonry structure based on the evaluation results; preliminarily determining the design parameters of the high-ductility cement-based composite material surface layer based on the seismic toughness improvement target; constructing a finite element model of the reinforced masonry structure based on the design parameters of the high-ductility cement-based composite material surface layer; evaluating the seismic toughness level of the reinforced masonry structure based on the finite element model; confirming whether the seismic toughness improvement target of the existing masonry structure is met based on the evaluation results; and obtaining the design parameters of the high-ductility cement-based composite material surface layer that meet the seismic toughness improvement target based on the confirmation results.

[0007] In one embodiment of the present invention, the step of evaluating the seismic toughness level of the existing masonry structure based on the finite element model of the existing masonry structure includes: selecting a suitable seismic ground motion record, performing an elastoplastic time history analysis on the finite element model of the existing masonry structure based on the selected suitable seismic ground motion record, obtaining the damage state of the existing masonry structure under seismic loading based on the analysis results, and calculating parameters related to the damage state based on the damage state, wherein the parameters related to the damage state include the repair cost index, repair time, personnel injury rate, and mortality rate of the existing masonry structure.

[0008] In one embodiment of the present invention, the step of performing elastoplastic time history analysis on the finite element model of the existing masonry structure based on the selected appropriate seismic ground motion record, obtaining the damage state of the existing masonry structure under seismic loading based on the analysis results, and calculating relevant parameters of the damage state based on the damage state includes: performing dynamic time history analysis on the finite element model of the existing masonry structure based on the selected appropriate seismic ground motion record, obtaining the vulnerability curve of the existing masonry structure based on the analysis results, and then calculating the functional and time toughness curve of the existing masonry structure, and calculating the repair cost index, repair time, personnel injury rate and mortality rate of the existing masonry structure under seismic loading based on the functional and time toughness curve of the existing masonry structure.

[0009] In one embodiment of the present invention, the seismic toughness improvement target of the existing masonry structure includes target repair cost index, target repair time, target personnel injury rate and target personnel mortality rate.

[0010] In one embodiment of the present invention, the design parameters of the high-ductility cement-based composite material surface layer include the material properties of the high-ductility cement-based composite material, the thickness of the reinforcing layer, and the arrangement scheme.

[0011] In one embodiment of the present invention, the step of evaluating the seismic toughness level of the reinforced masonry structure based on the finite element model of the reinforced masonry structure includes: performing elastoplastic time history analysis on the finite element model of the reinforced masonry structure, obtaining the damage state of the reinforced masonry structure under seismic loading based on the analysis results, and calculating the repair cost index, repair time, personnel injury rate and mortality rate of the reinforced masonry structure based on the damage state.

[0012] In one embodiment of the present invention, the step of performing elastoplastic time history analysis on the finite element model of the reinforced masonry structure, obtaining the damage state of the reinforced masonry structure under seismic loading based on the analysis results, and calculating the repair cost index, repair time, personnel injury rate, and mortality rate of the reinforced masonry structure based on the damage state includes: performing dynamic time history analysis on the finite element model of the reinforced masonry structure, obtaining the vulnerability curve of the reinforced masonry structure based on the analysis results, then calculating the functional and time toughness curve of the reinforced masonry structure, and calculating the repair cost index, repair time, personnel injury rate, and mortality rate of the reinforced masonry structure under seismic loading based on the functional and time toughness curve of the reinforced masonry structure.

[0013] In one embodiment of the present invention, the step of confirming whether the seismic toughness improvement target of the existing masonry structure is met based on the evaluation result, and obtaining the design parameters of the high-ductility cement-based composite material surface layer that meet the seismic toughness improvement target based on the confirmation result, includes: determining whether the seismic toughness improvement target of the existing masonry structure is met based on the evaluation result; if not, continuing to determine the design parameters of the high-ductility cement-based composite material surface layer until the design parameters of the high-ductility cement-based composite material surface layer that meet the seismic toughness improvement target are obtained.

[0014] As described above, the present invention provides a design method for reinforcing masonry structures with high-ductility cement-based composite materials based on toughness, which has the following beneficial effects: The present invention organically combines quantified seismic toughness with reinforcement design schemes, and uses new high-performance materials to establish a reinforcement design method for existing masonry structures, so as to improve the seismic toughness level of existing masonry structures; therefore, the present invention not only considers the improvement of the seismic performance of existing masonry structures, but also considers the optimization of structural repair time and repair costs, that is, it not only meets the goal of life safety, but also meets the goal of post-earthquake functional restoration. Attached Figure Description

[0015] Figure 1 The diagram shows the overall flowchart of the design method for reinforced masonry structures based on toughness-based high-ductility cement-based composite materials disclosed in the embodiments of the present invention.

[0016] Figure 2 The diagram shown is a plan view of an existing masonry structure in the design method for reinforcing masonry structures based on toughness-based high-ductility cement-based composite materials disclosed in this embodiment of the invention.

[0017] Figure 3 The diagram shows the vulnerability curve of an existing masonry structure in the design method for reinforcing masonry structures based on toughness-based high-ductility cement-based composite materials disclosed in this embodiment of the invention.

[0018] Figure 4 The diagram shows the function-time toughness curve of an existing masonry structure in the design method for reinforcing masonry structures based on toughness-high ductility cement-based composite materials disclosed in this embodiment of the invention.

[0019] Figure 5 The diagram shows the vulnerability curve of the reinforced masonry structure in the design method of reinforced masonry structure based on toughness and high ductility cement-based composite materials disclosed in the embodiments of the present invention.

[0020] Figure 6 The diagram shows the function-time toughness curve of the reinforced masonry structure in the design method of reinforced masonry structure based on toughness-high ductility cement-based composite materials disclosed in the embodiments of the present invention. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, unless otherwise specified, the following embodiments and features described herein can be combined with each other.

[0022] This invention provides a design method for reinforcing masonry structures with high-ductility cement-based composite materials based on toughness, the process of which is as follows: Figure 1 As shown, the details are as follows:

[0023] Step 101: Obtain the basic information of the existing masonry structure to be reinforced, construct a finite element model of the existing masonry structure based on the basic information, and evaluate the seismic toughness level of the existing masonry structure based on the finite element model of the existing masonry structure.

[0024] Specifically, the basic information of the existing masonry structure to be reinforced is obtained, and a finite element model of the existing masonry structure is established in finite element software based on this basic information. Then, a suitable seismic ground motion record is selected as input, and an elastoplastic time history analysis is performed on the finite element model of the existing masonry structure based on the selected suitable seismic ground motion record, so as to obtain the damage state of the existing masonry structure under seismic action, and the repair cost index, repair time, personnel injury rate and mortality rate of the existing masonry structure are calculated based on the damage state.

[0025] In practical applications, firstly, determine the basic information of the existing masonry structure: Consider a 5-story existing masonry structure, using MU10 grade sintered clay bricks and M2.5 grade mixed mortar, with a floor height of 3m, a transverse width of 9.3m, a longitudinal length of 26.4m, and a wall thickness of 240mm. Please refer to the structural plan. Figure 2 The calculated shear wall area ratio is 0.049 in the axial direction and 0.084 in the orthogonal direction. The gravity load factor per unit building area is 1.0. The seismic fortification intensity is 7 degrees, and the basic design seismic acceleration is 0.10g (g is the gravitational acceleration, g=9.8m / s²). 2 );

[0026] Secondly, 25 actual seismic ground motions were selected, and a finite element model of the existing masonry structure was established using finite element software based on the basic information of the existing masonry structure. Dynamic time history analysis was then performed on the structural model to obtain the vulnerability curves of the building structure. For details, please refer to [link to relevant documentation]. Figure 3 Then, the function-time toughness curve of the existing masonry structure is calculated, that is, the relationship between the repair cost index and the repair time, such as... Figure 4 As shown;

[0027] Finally, the calculated repair costs, repair time, injury rate, and mortality rate for existing masonry structures during rare earthquakes were 19.1%, 35.9 days, and 1.56 × 10⁻⁶ days, respectively. -2 and 4.74×10 -3 .

[0028] Step 102: Determine the seismic toughness improvement target for existing masonry structures based on the assessment results.

[0029] Specifically, the seismic toughness improvement targets for the existing masonry structure include target repair cost indicators, target repair time, target personnel injury rate, and target personnel mortality rate.

[0030] In practical applications, the seismic toughness improvement targets for this existing masonry structure are determined as follows: the repair cost of the existing masonry structure under rare earthquakes should not exceed 10%, the repair time should not exceed 30 days, and the injury rate and mortality rate should not exceed 1.0 × 10⁻⁶. -3 and 1.0×10 -4 .

[0031] Step 103: Based on the seismic toughness improvement target, the design parameters of the high-ductility cement-based composite material surface layer are initially determined.

[0032] Specifically, the design parameters for the high-ductility cement-based composite surface layer include the material properties of the high-ductility cement-based composite, the thickness of the reinforcement layer, and the layout scheme.

[0033] In practical applications, the compressive strength and tensile strength of the high-ductility cement-based composite material are selected as 36.0 MPa and 4.5 MPa, respectively, and the ultimate tensile strain is 2.8%. The thickness of the high-ductility cement-based composite material surface layer is 40 mm during reinforcement, and the reinforcement layer layout scheme is to coat the entire exterior wall surface.

[0034] Step 104: Construct a finite element model of the reinforced masonry structure based on the design parameters of the high-ductility cement-based composite material surface layer, and evaluate the seismic toughness level of the reinforced masonry structure based on the finite element model of the reinforced masonry structure.

[0035] Specifically, a finite element model of the reinforced masonry structure is established based on the design parameters of the high-ductility cement-based composite material surface layer, and an elastoplastic time history analysis is performed on it to obtain the damage state of the reinforced masonry structure under seismic action, and to calculate its repair cost index, repair time, personnel injury rate and mortality rate; it should be noted that the reinforced masonry structure in this embodiment is the existing masonry structure after reinforcement.

[0036] In practical applications, a finite element model of the reinforced masonry structure is established using finite element software and based on the design parameters of the high-ductility cement-based composite surface layer. Dynamic time history analysis is then performed to obtain the vulnerability curve of the reinforced masonry structure. For details, please refer to [link to relevant documentation]. Figure 5 Then, the function-time toughness curve of the reinforced masonry structure is calculated, which shows the relationship between repair cost and repair time. Figure 6 As shown;

[0037] The calculated repair costs, repair time, injury rate, and mortality rate for reinforced masonry structures during rare earthquakes are 1.3%, 4.0 days, and 4.35 × 10⁻⁶ days, respectively. -6 and 1.71×10 -7 .

[0038] Step 105: Determine whether the seismic toughness improvement target of the existing masonry structure is met based on the evaluation results. If it is met, proceed to step 106; otherwise, proceed to step 103.

[0039] Step 106: The existing masonry structure to be reinforced is reinforced using this reinforcement method.

[0040] Specifically, determine whether the calculation results in step 104 meet the target repair cost index, target repair time, target personnel injury rate, and target personnel mortality rate. If the target performance is met, the reinforcement design is completed. If not, repeat steps 103-104 until the target performance is met.

[0041] In practical applications, based on the results calculated in step 104, the repair cost index, repair time, injury rate, and mortality rate of the reinforced masonry structure are all less than the target values, meeting the target performance, and this reinforcement method can be used for reinforcement.

[0042] In summary, this invention organically combines quantified seismic toughness with reinforcement design schemes, and uses novel high-performance materials to establish a reinforcement design method for existing masonry structures, thereby improving the seismic toughness level of existing masonry structures. Therefore, this invention not only considers the improvement of the seismic performance of existing masonry structures, but also the optimization of structural repair time and repair costs, that is, it not only meets the goal of life safety, but also the goal of post-earthquake functional restoration.

[0043] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. All equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. A design method for masonry structures reinforced with high-ductility cement-based composite materials based on toughness, characterized in that, The method includes the following steps: Obtain the basic information of the existing masonry structure to be reinforced, construct a finite element model of the existing masonry structure based on the basic information, and evaluate the seismic toughness level of the existing masonry structure based on the finite element model of the existing masonry structure. Based on the assessment results, determine the seismic toughness improvement target for existing masonry structures; Based on the stated seismic toughness enhancement target, the design parameters of the high-ductility cement-based composite material surface layer are preliminarily determined; A finite element model of the reinforced masonry structure was constructed based on the design parameters of the high-ductility cement-based composite material surface layer, and the seismic toughness level of the reinforced masonry structure was evaluated based on the finite element model of the reinforced masonry structure. Based on the assessment results, it is confirmed whether the seismic toughness improvement target of the existing masonry structure is met. Based on the confirmation results, the design parameters of the high-ductility cement-based composite material surface layer that meets the seismic toughness improvement target are obtained.

2. The design method for reinforced masonry structures based on toughness-enhanced high-ductility cement-based composite materials according to claim 1, characterized in that: The assessment of the seismic toughness level of existing masonry structures based on finite element models includes: Select appropriate ground motion records and perform elastoplastic time history analysis on the finite element model of the existing masonry structure based on the selected appropriate ground motion records. Obtain the damage state of the existing masonry structure under seismic loading based on the analysis results, and calculate the relevant parameters of the damage state based on the damage state. The relevant parameters of the damage state include the repair cost index, repair time, personnel injury rate and mortality rate of the existing masonry structure.

3. The design method for reinforced masonry structures based on toughness-enhanced high-ductility cement-based composite materials according to claim 2, characterized in that: The process involves performing an elastoplastic time history analysis on a finite element model of an existing masonry structure based on selected appropriate seismic ground motion records. The damage state of the existing masonry structure under seismic loading is obtained from the analysis results, and parameters related to the damage state are calculated based on this damage state, including: Dynamic time history analysis was performed on the finite element model of the existing masonry structure based on the selected appropriate ground motion records. The vulnerability curve of the existing masonry structure was obtained based on the analysis results. Then, the functional and time toughness curves of the existing masonry structure were calculated. Based on the functional and time toughness curves of the existing masonry structure, the repair cost index, repair time, personnel injury rate and mortality rate of the existing masonry structure under earthquake action were calculated.

4. The design method for reinforced masonry structures based on toughness-enhanced high-ductility cement-based composite materials according to claim 2, characterized in that: The seismic toughness improvement targets for existing masonry structures include target repair cost indicators, target repair time, target personnel injury rate, and target personnel mortality rate.

5. The design method for masonry structure reinforced with high-ductility cement-based composite materials based on toughness according to claim 1, characterized in that: The design parameters of the high-ductility cement-based composite surface layer include the material properties of the high-ductility cement-based composite material, the thickness of the reinforcement layer, and the layout scheme.

6. The design method for reinforced masonry structures based on toughness-enhanced high-ductility cement-based composite materials according to claim 2, characterized in that: The evaluation of the seismic toughness level of the reinforced masonry structure based on the finite element model of the reinforced masonry structure includes: Elastoplastic time history analysis was performed on the finite element model of the reinforced masonry structure. Based on the analysis results, the damage state of the reinforced masonry structure under seismic loading was obtained. Based on the damage state, the repair cost index, repair time, personnel injury rate and mortality rate of the reinforced masonry structure were calculated.

7. The design method for reinforced masonry structures based on toughness-enhanced high-ductility cement-based composite materials according to claim 6, characterized in that: The finite element model of the reinforced masonry structure is subjected to elastoplastic time history analysis. Based on the analysis results, the damage state of the reinforced masonry structure under seismic loading is obtained. Then, based on the damage state, the repair cost, repair time, personnel injury rate, and mortality rate of the reinforced masonry structure are calculated, including: Dynamic time history analysis was performed on the finite element model of the reinforced masonry structure. Based on the analysis results, the vulnerability curve of the reinforced masonry structure was obtained. Then, the functional and time toughness curves of the reinforced masonry structure were calculated. Based on the functional and time toughness curves of the reinforced masonry structure, the repair cost index, repair time, personnel injury rate and mortality rate of the reinforced masonry structure under seismic action were calculated.

8. The design method for reinforced masonry structures based on toughness-enhanced high-ductility cement-based composite materials according to claim 1, characterized in that: The process involves confirming whether the seismic toughness improvement target of the existing masonry structure is met based on the evaluation results, and obtaining the design parameters of the high-ductility cement-based composite material surface layer that meets the seismic toughness improvement target based on the confirmation results, including: Based on the assessment results, determine whether the seismic toughness improvement target of the existing masonry structure is met. If not, continue to determine the design parameters of the high-ductility cement-based composite material surface layer until the design parameters of the high-ductility cement-based composite material surface layer that meet the seismic toughness improvement target are obtained.

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