Unreinforced masonry structure bearing capacity degradation simulation and reinforcement effect evaluation method
By constructing a physical model of unreinforced masonry structures and introducing environmental factors, the change in bearing capacity was simulated, which solved the problem of quantitative degradation in the assessment of the bearing capacity of unreinforced masonry structures, realized the scientific quantitative assessment of the reinforcement effect, and improved the prediction accuracy and the scientific nature of the reinforcement scheme.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA POWER CONSTR GRP ARCHITECTURAL PLANNING & DESIGN INST CO LTD
- Filing Date
- 2026-01-29
- Publication Date
- 2026-05-01
AI Technical Summary
The existing technology for assessing the load-bearing capacity of unreinforced masonry structures lacks a quantitative degradation model that considers time and environmental factors, leading to conservative or insufficient reinforcement scheme design and a lack of scientific quantitative means to predict their long-term safety.
A physical model of an unreinforced masonry structure was constructed, vertical and horizontal loads were analyzed, initial parameters were set and environmental influence factors were introduced, a degradation model of the masonry's compressive and shear strengths was established, the bearing capacity changes were simulated using programming tools, and a composite wall was constructed using reinforcement materials and its equivalent strength was calculated.
It enables dynamic prediction of the bearing capacity of unreinforced masonry structures, improves prediction accuracy, provides a scientific basis for reinforcement decisions, and significantly enhances the quantitative evaluation of reinforcement effects.
Smart Images
Figure CN121959953A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of building structure engineering technology, specifically relating to a method for simulating the degradation of the bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect. Background Technology
[0002] Unreinforced masonry structures are widely found in older residential buildings, public buildings, and industrial plants. With increasing service life, material properties gradually degrade due to environmental factors (such as humidity and temperature changes), leading to a decrease in structural load-bearing capacity and posing safety hazards. Currently, the assessment of the load-bearing capacity of masonry structures is mostly based on static testing or empirical judgment, lacking quantitative degradation models that consider the coupling effect of time and environmental factors. Furthermore, although methods such as external concrete encasing are commonly used for reinforcement, the performance degradation pattern of the reinforced structure over its remaining service life is still unclear, and there is a lack of scientific quantitative means to predict its long-term safety, resulting in conservative or inadequate reinforcement scheme designs.
[0003] In view of this, the present invention is hereby proposed. Summary of the Invention
[0004] To address the aforementioned technical problems in the existing technology, this invention provides a method for simulating the load-bearing capacity degradation of unreinforced masonry structures and evaluating the effectiveness of reinforcement measures. This method solves the problem of difficulty in quantifying and predicting the long-term performance degradation of masonry structures and the effectiveness of reinforcement measures in the existing technology, and provides a scientific basis for the durability design, safety assessment, and reinforcement decision-making of existing masonry structures.
[0005] To achieve the above objectives, the technical solution of the present invention is as follows:
[0006] A method for simulating the bearing capacity degradation of unreinforced masonry structures and evaluating the reinforcement effect includes: S1. Construct a physical model of the unreinforced masonry structure, analyze the pressure generated by the vertical load and the shear force generated by the horizontal load, and obtain the compressive bearing capacity and shear bearing capacity index of the masonry structure. S2. Set initial parameters, including material parameters, geometric parameters, environmental parameters and degradation rate parameters, and introduce environmental impact factors to correct the degradation rate parameters; S3. Based on the time decay law and combined with environmental influences, degenerative models of masonry compressive strength and shear strength are constructed respectively. Then, combined with geometric parameters and stability coefficients, time-varying models of compressive bearing capacity and shear bearing capacity are constructed. The degenerative model and the time-varying model are simulated and calculated using programming tools to output the variation law of unreinforced masonry bearing capacity over time. S4. Based on the variation law of unreinforced masonry bearing capacity output in step S3, reinforce the unreinforced masonry wall with reinforcement materials to construct a composite wall, and establish a strength degradation model of the reinforcement material and the original masonry in the composite wall. S5. The equivalent compressive strength and equivalent shear strength of the composite wall are calculated using the area-weighted method. Based on the equivalent compressive strength and equivalent shear strength, a time-varying model of the bearing capacity of the composite wall is constructed. The strength degradation model and time-varying model of the composite wall are simulated and calculated using a programming tool, and the variation law of the bearing capacity of the composite wall over time is output. S6. Compare the variation law of unreinforced masonry bearing capacity output in step S3 with the variation law of composite wall bearing capacity output in step S5.
[0007] Furthermore, the calculation unit of the physical model of the unreinforced masonry structure is set to have a height of 3m, a thickness of 0.2m, and a length of 1m.
[0008] Furthermore, the material parameters include the initial compressive strength of the unreinforced masonry. With initial shear strength ; Among them, initial compressive strength initial shear strength .
[0009] Furthermore, the geometric parameters include the cross-sectional area of the computational unit. With wall height and cross-sectional area , ; The environmental parameters include humidity coefficient. With temperature ,in And the value is truncated to [0.3, 0.99]. .
[0010] Furthermore, the degradation rate parameter includes the annual degradation rate of masonry compressive strength. Annual degradation rate of shear strength ,and , ; The formula for calculating the environmental impact factors is as follows: The corrected degradation rate corresponds to the original degradation rate and the environmental impact factor. The product of.
[0011] Furthermore, the stability coefficient The calculation formula is:
[0012] in, The slenderness ratio of an unreinforced masonry member; The degradation model for the compressive strength of masonry is as follows:
[0013] in, Initial compressive strength, The annual degradation rate of compressive strength, Humidity coefficient; The shear strength degradation model is as follows:
[0014] in, The initial shear strength, The annual degradation rate of shear strength, This is the humidity coefficient.
[0015] Furthermore, the reinforcing material is a concrete slab, and the thickness of the concrete slab is set to 70mm.
[0016] Furthermore, the strength degradation model of the reinforcing material includes: a concrete compressive strength degradation model and a concrete shear strength degradation model; specifically including:
[0017]
[0018] in, This represents the time-varying value of the concrete compressive strength. This represents the time-varying value of the shear strength of concrete. This refers to the initial compressive strength of the concrete. This refers to the initial shear strength of the concrete. The annual degradation rate of concrete compressive strength; This represents the annual degradation rate of concrete shear strength.
[0019] Furthermore, the equivalent strength formula for the composite wall is: Equivalent compressive strength:
[0020] Equivalent shear strength:
[0021] in, The projected area of the masonry cross-section; The projected area of the concrete slab cross section; This represents the time-varying value of the masonry compressive strength. This represents the time-varying value of the shear strength of the masonry. This represents the time-varying value of the concrete compressive strength. This represents the time-varying value of the shear strength of concrete.
[0022] Furthermore, the bearing capacity formula for the composite wall is:
[0023]
[0024]
[0025] in, The projected area of the composite wall section; To assess the compressive bearing capacity of the composite wall; This refers to the shear bearing capacity of the composite wall.
[0026] Compared with existing technologies, the present invention provides a method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the effect of reinforcement. The method includes: constructing a general physical model and conducting stress analysis; setting four initial parameters: material, geometry, environment, and degradation rate; introducing environmental influence factors based on humidity and temperature to correct the degradation rate; establishing a degradation model of masonry compressive and shear strength by combining time decay laws and environmental influences; constructing a time-varying model of bearing capacity; simulating and outputting the time-varying law of the bearing capacity of unreinforced masonry through programming tools; constructing a composite wall using an outer concrete slab; calculating the equivalent strength based on the area-weighted method and establishing its time-varying model of bearing capacity; simulating and obtaining the law of change in bearing capacity after reinforcement; and achieving a quantitative evaluation of the reinforcement effect by comparing the two. This invention achieves a leap from static evaluation to dynamic prediction, with high prediction accuracy and convenient operation, providing a scientific basis for the safety assessment, durability evaluation, and reinforcement decision-making of existing masonry structures. Attached Figure Description
[0027] Figure 1 This is a model diagram of an unreinforced masonry calculation unit provided in an embodiment of the present invention; Figure 2 This is a simulation diagram of the bearing capacity of unreinforced masonry changing over time, provided in an embodiment of the present invention. Figure 3 Frequency distribution diagram of unreinforced masonry samples provided in embodiments of the present invention; Figure 4 This is a trend diagram of the bearing capacity degradation of unreinforced masonry provided in an embodiment of the present invention. Figure 5 Detailed drawings of the construction method for encasing unreinforced masonry walls with concrete slabs, provided in an embodiment of the present invention; Figure 6 This is a simulation diagram of the bearing capacity of the composite wall changing over time, provided in an embodiment of the present invention. Figure 7 The embodiment of this invention provides a simulation diagram of the bearing capacity of the wall before reinforcement; Figure 8 This is a simulation diagram of the bearing capacity of the reinforced wall provided in an embodiment of the present invention. Detailed Implementation
[0028] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.
[0029] It should be noted that, unless otherwise specifically stated, the relative arrangement and numerical expressions of the components and steps described in these embodiments should not be construed as limiting the scope of the invention.
[0030] The following description of exemplary embodiments is merely illustrative and is not intended to limit the invention or its application or use in any way. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail herein, but where applicable, such techniques, methods, and apparatus should be considered part of this specification.
[0031] Example 1 The present invention proposes a method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the effect of reinforcement, the specific steps of which may include: S1. Construct a physical model of the unreinforced masonry structure, analyze the pressure generated by the vertical load and the shear force generated by the horizontal load, and obtain the compressive bearing capacity and shear bearing capacity index of the masonry structure. Unreinforced masonry structures refer to masonry structures without steel reinforcement or with only a small amount of non-load-bearing steel reinforcement. They rely on the material properties of the masonry itself to resist external forces and are widely used in low-rise residential buildings, walls, ancillary buildings, and other buildings with relatively small loads. To study the stress performance of unreinforced masonry structures, it is first necessary to establish a general physical model. Referring to the conventional design parameters of low-rise masonry residential buildings, a height of 3m and a thickness of 0.2m are selected, and a 1m length is taken as one calculation unit.
[0032] See Figure 1 After establishing this calculation unit, stress analysis is performed. Masonry walls mainly bear vertical loads such as the structure's self-weight and horizontal loads such as seismic action. Vertical loads generate downward pressure, while horizontal loads generate horizontal shear forces. The compressive bearing capacity and shear bearing capacity of masonry structures are the main indicators of their stress performance. Studying the time-related degradation of both can provide a scientific basis for structural durability design and reinforcement decisions.
[0033] S2. Set initial parameters, including material parameters, geometric parameters, environmental parameters, and degradation rate parameters, and introduce an environmental impact factor to correct the degradation rate parameters; specifically including: S21, Material Parameters The mean and standard deviation of the initial compressive strength and initial shear strength were determined by referring to the properties of common unreinforced masonry materials and combining statistical data from the "Code for Design of Masonry Structures" and experimental literature. In actual engineering, differences in the strength of bricks and the quality of mortar construction within the same batch lead to fluctuations in material properties. A normal distribution (N-distribution) is used to characterize this randomness. The mean is the design expectation value, and the standard deviation reflects the fluctuations in construction and materials.
[0034] Initial compressive strength The expression is: ; The expression for the initial shear strength is: .
[0035] S22, Geometric parameters S221. Geometric parameters are based on conventional design dimensions, supplemented by construction errors, and the randomness of dimensions is reflected through a normal distribution; specifically including: Cross-sectional area A: Based on the design cross-section of common unreinforced masonry components, such as a wall thickness of 0.2m and a calculation unit of 1m, the stressed cross-section is approximately 0.2m²; the expression for the cross-sectional area is: .
[0036] Wall height h: Based on a standard floor height of 3.0m, conforming to the typical masonry wall height of residential and public buildings; the expression for wall height is: .
[0037] S222. Due to deviations during construction (such as uneven wall thickness, inconsistent mortar thickness, and local dimensional deviations), a certain standard deviation is introduced based on the mean; the magnitude of the standard deviation is generally taken from the mean. It can reflect actual fluctuations without causing unreasonable dimensions.
[0038] S223. Using a normal distribution to describe the geometric dimensions, the geometric dimensions usually fluctuate around the target value during design and construction, which is consistent with the characteristics of being concentrated near the mean and having small deviations. Therefore, it is reasonable to assume that they follow a normal distribution.
[0039] S23, Environmental Parameters S231. Determining the mean based on typical climatic conditions, specifically including: Humidity H: Values are taken from long-term meteorological observation data, set between 0.3 and 0.99, with a mean of 0.7 corresponding to the moderate humidity environment commonly found in temperate regions; the expression for humidity H is: .
[0040] Temperature T: The value is taken from the average annual temperature, with the mean set at 15℃, which is consistent with the long-term service environment of masonry structures in most regions; the expression for temperature T is: .
[0041] S232. Considering climate fluctuations and uncertainties, humidity and temperature will fluctuate in different seasons, day and night and different years. Therefore, standard deviations are introduced on the basis of the mean (humidity is ±0.15 and temperature is ±5℃).
[0042] S233. A normal distribution is used for approximation. Humidity and temperature changes are mostly concentrated, and extreme values are relatively rare; therefore, a normal distribution is used for approximation modeling. At the same time, humidity values are truncated, limited to... To ensure the results are reasonable.
[0043] S24, Degradation Rate Parameter S241, based on literature and normative empirical values.
[0044] Relevant literature and standards often provide empirical ranges for the rate of material strength decay over time. The annual degradation rate of masonry compressive strength is 0.3% to 1%, and the annual degradation rate of shear strength is 0.5% to 1.5%. Therefore, the average value of the compressive strength degradation rate is taken as 0.005 (i.e., 0.5% / year), and the average value of the shear degradation rate is taken as 0.008 (i.e., 0.8% / year).
[0045] S242. Consider structural and environmental differences.
[0046] Due to differences in construction quality, material composition, and service environment, the degradation rate is uncertain. Therefore, a standard deviation (compression ±0.001, shear ±0.0015) is assigned to the mean. This reflects the reality that some components degrade faster or slower.
[0047] S243. Use normal distribution for modeling.
[0048] The degradation rate is generally concentrated at the average level with few extreme values, so a normal distribution is adopted. At the same time, the degradation rate is adjusted by environmental factors to conform to actual working conditions.
[0049] S244, Environmental Factor Correction.
[0050] The environmental impact factors, through linear corrections for humidity and temperature, reflect the accelerating effect of climate conditions on the degradation rate, ensuring both physical plausibility and model simplicity; the specific formula is as follows:
[0051] Among them, 0.7 is the baseline value, which means that even in relatively ideal environments (moderate humidity, close to normal temperature), there is still a certain level of natural degradation; The humidity term indicates that the higher the humidity, the faster the deterioration processes such as carbonization and steel corrosion occur, hence the positive correlation. For temperature deviation, the greater the temperature deviation from normal temperature (20°C), the more significant the freeze-thaw or thermal expansion and contraction effect, and the faster the degradation.
[0052] Compression degradation rate:
[0053] Shear degradation rate:
[0054] S3. Based on the time decay law and environmental influences, degradation models of masonry compressive strength and shear strength are constructed respectively. Then, combined with geometric parameters and stability coefficients, time-varying models of compressive bearing capacity and shear bearing capacity are constructed. Simulation calculations are performed on the degradation models and time-varying models using programming tools to output the variation law of unreinforced masonry bearing capacity over time; specifically including: S31. Construct a model for compressive strength degradation. S311. Degradation Mechanism: During long-term service, masonry is affected by factors such as carbonation, freeze-thaw cycles, humidity, temperature stress, and accumulation of microcracks, which gradually reduce its compressive strength. The strength reduction usually exhibits a pattern of decreasing over time, with a faster initial decrease followed by a slower decrease later.
[0055] S312, Degradation Model:
[0056] in, This represents the initial compressive strength. The annual degradation rate of compressive strength reflects the average impact of the material itself and the environment on the degradation rate. Humidity coefficient; This is a humidity correction factor; the higher the humidity, the more severe the microcracks and carbonization, and therefore the slightly lower the strength.
[0057] This model takes into account both the statistical regularity of experimental results (exponential decay) and the influence of environmental conditions (humidity correction); it maintains the simplicity of the model while reflecting the influence of multiple factors on the strength of masonry.
[0058] S32. Construct a shear strength degradation model S321. Degradation Mechanism: Shear performance is mainly affected by mortar bonding degradation, crack propagation, and the effects of humidity and temperature cycles. In high humidity environments, mortar softening and bonding strength decrease significantly; the development of microcracks caused by temperature changes also accelerates shear strength degradation.
[0059] S322, Degeneracy Model:
[0060] in, This represents the initial shear strength. The annual degradation rate of shear strength is usually greater than that of compressive strength, indicating that shear capacity is more sensitive. Humidity coefficient; This is a humidity correction term; humidity has a stronger impact on shear strength (coefficient). This is consistent with experimental phenomena.
[0061] The shear strength degrades faster than the compressive strength, which is consistent with the actual law that masonry structures first lose their bonding properties and then gradually lose their compressive capacity in humid environments; the humidity correction enhances the model's adaptability to differences in service environments.
[0062] S33. Construct a model for degradation of compressive bearing capacity. The compressive bearing capacity depends on the material strength × component area × stability correction. That is, the pressure that a component can withstand comes from the compressive strength of the masonry itself, but is affected by its geometry and slenderness ratio.
[0063] S331, stability coefficient is:
[0064] in, The slenderness ratio reflects the stability of masonry components under compression; the larger the slenderness ratio, the more prone the component is to instability, and the more significant the reduction in bearing capacity; the coefficient 0.0015 comes from empirical data to ensure that the reduction is reasonable within the range of common slenderness ratios.
[0065] S332, The calculation formula is: Compressive bearing capacity:
[0066] The final formula is:
[0067] in, This is a strength term, reflecting the degradation of a material's compressive strength over time; As an area term, the larger the cross-section, the higher the bearing capacity. To provide a stability coefficient, the slenderness ratio effect is introduced to make the formula more consistent with the stability characteristics of actual compression members.
[0068] S34. Construct a model for the degradation of shear bearing capacity. The formula for shear bearing capacity is based on shear strength × cross-sectional area, which directly reflects the control effect of material bonding performance and geometric dimensions on shear capacity, without the need for stability coefficient correction; shear strength reflects the bonding and frictional ability between the masonry mortar interface and the overall material, which gradually decreases with time and environment; S341, The calculation formula is: Shear bearing capacity:
[0069] The final formula is:
[0070] in, The cross-sectional area is the maximum area that can withstand the shear force. Unlike compression, shear bearing capacity is mainly controlled by material properties and cross-sectional dimensions, with the slenderness ratio having a smaller impact. Therefore, the formula is simpler.
[0071] The formula embodies the fundamental mechanical logic of "strength × area"; through The inclusion of degradation and environmental impact ensures the rationality of changes over time; it conforms to the simplified calculation approach in masonry structure design.
[0072] S35. Perform simulation calculations on the degradation model and time-varying model using the Matlab programming tool. S351. Initial Parameter Assignment: Before simulating compressive and shear bearing capacities using Matlab software, all parameters in the formulas must be assigned appropriate values. Refer to Table 1 for specific parameter settings. Table 1 Initial Parameters
[0073] S352, Program Simulation Steps: In Matlab software, time-dependent calculations of compressive and shear bearing capacities were performed, and the calculation results were statistically analyzed. The output results after running the Matlab program code are shown in the attached document. Figures 2-4 The following conclusions can be drawn from the analysis of the results: See Figure 2 , Figure 2 Here is a simulation diagram showing the change in bearing capacity of unreinforced masonry over time: Compressive bearing capacity: It gradually decreased from about 1750 kN initially to about 1350 kN after 50 years, which shows that the compressive strength of unreinforced masonry walls is constantly decreasing over time.
[0074] Shear bearing capacity: It gradually decreased from about 54 kN initially to about 37 kN after 50 years, and the shear capacity continued to weaken.
[0075] See Figure 3 , Figure 3 Frequency distribution diagram of unreinforced masonry samples: The distribution of compressive bearing capacity degradation is bell-shaped, approximately normal, with a peak value of around 25%. This indicates that after 50 years, the compressive bearing capacity of the component is most likely to degrade by about 25%.
[0076] Shear capacity degradation distribution: The distribution is also bell-shaped, with a peak value of about 36%, which indicates that after 50 years, the shear capacity of the component is most likely to degrade by about 36%.
[0077] See Figure 4 , Figure 4 Chart showing the trend of load-bearing capacity degradation of unreinforced masonry: Compressive bearing capacity: The percentage of bearing capacity decreased from 100% to about 75% after 50 years, a degradation of about 25%. The degradation rate was relatively slow, and the curve changed relatively gently.
[0078] Shear capacity: The percentage of bearing capacity decreased from 100% to approximately 64% after 50 years, a degradation of about 36%. Compared with compressive bearing capacity, shear capacity degrades significantly faster and at a steeper rate.
[0079] S4. Based on the variation law of unreinforced masonry bearing capacity output in step S3, reinforce the unreinforced masonry wall with reinforcement materials to construct a composite wall, and establish a strength degradation model of the reinforcement material and the original masonry in the composite wall. In the reinforcement and renovation projects of old residential areas, there are various reinforcement measures for unreinforced masonry walls. For specific reinforcement methods, please refer to [link / reference needed]. Figure 5 , Figure 5 Detailed drawings of the construction method for encasing unreinforced masonry walls with concrete slabs; see reference. Figure 6 An aging degradation analysis of the compressive and shear bearing capacities of composite walls reinforced with external concrete was conducted to provide a reference for the safety evaluation of reinforced buildings.
[0080] The specific strength degradation model for concrete slabs is as follows:
[0081]
[0082] in, This represents the time-varying value of the concrete compressive strength. This represents the time-varying value of the shear strength of concrete. The initial compressive strength of the concrete is taken in the model. ; The initial shear strength of the concrete is taken in the model. ; The annual degradation rate of concrete compressive strength is taken in the model. ; The annual degradation rate of concrete shear strength is taken in the model. ; S5. The equivalent compressive strength and equivalent shear strength of the composite wall are calculated using the area-weighted method. Based on the equivalent strength, a time-varying model of the bearing capacity of the composite wall is constructed. The strength degradation model and time-varying model of the composite wall are simulated and calculated using a programming tool, and the variation law of the bearing capacity of the composite wall over time is output. The formula for the equivalent strength of composite walls is as follows: the concrete slab and masonry are subjected to the same force, and the area-weighted method is used to calculate the equivalent strength of the composite walls.
[0083] Equivalent compressive strength:
[0084] Equivalent shear strength:
[0085] in, The projected area of the masonry cross-section; This represents the projected area of the concrete slab cross-section.
[0086] The formula for the bearing capacity of composite walls is:
[0087]
[0088]
[0089] in, The projected area of the composite wall section; To assess the compressive bearing capacity of the composite wall; This refers to the shear bearing capacity of the composite wall.
[0090] S6. Compare the variation law of unreinforced masonry bearing capacity output in step S3 with the variation law of composite wall bearing capacity output in step S5.
[0091] A program was written using MATLAB software to analyze the degradation of the compressive and shear bearing capacity of composite walls. The analysis of the results showed that the compressive and shear bearing capacity of the composite walls reinforced with reinforced concrete slabs were significantly improved, and the rate of degradation over subsequent service years was significantly slowed down, indicating a significant reinforcement effect.
[0092] Example 2 This embodiment adopts a method for simulating the degradation of the bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect. The background is No. 2 residential building in Courtyard No. 17, Daliushu Road, Haidian District, Beijing. It was built in the 1980s and has not undergone seismic reinforcement since its construction. The building underwent a safety assessment in 2021. According to the investigation, the building has not suffered any disasters or accidents.
[0093] The building is rectangular in layout, a four-story brick-concrete structure, intended for residential use. The total height is 12.600m, with each floor from the first to the fourth floor having a height of 3.000m. The building's total length (east-west) is 42.000m, and its total width (north-south) is 9.900m. The load-bearing walls are constructed of sintered common bricks and mixed mortar, with a wall thickness of 240mm. Detailed data in the appraisal report can be found in Table 3. Table 2. Appraisal Report Form
[0094] This project plans to reinforce the walls using a 70mm single-sided reinforced concrete slab wall on the outside of the masonry wall. The concrete strength grade is C30, and the design service life after reinforcement is 50 years. (See reference) Figure 7 and Figure 8 Using the research method of this patent, the load-bearing capacity changes over subsequent years of the original wall and the reinforced wall were simulated, and the superiority and effectiveness of the reinforcement scheme were compared and demonstrated. The model running parameters are shown in Table 3. Table 3 Parameter Setting Table
[0095] Analysis of running results: By running the two codes in MATLAB, simulation diagrams of the bearing capacity of the wall before and after reinforcement of the Liushu Road project were obtained. The analysis of the running results showed that the compressive bearing capacity and shear bearing capacity of the reinforced wall were significantly improved, and the rate of degradation in subsequent service life was slowed down, which quantitatively demonstrated the reinforcement effect of the external reinforced concrete slab.
[0096] In summary, the present invention has the following advantages: 1. It has achieved a leap from static assessment to dynamic prediction. By establishing a degradation model that considers the coupling effect of time and environment, it is possible to dynamically simulate the load-bearing capacity decay process of the structure throughout its entire design service life. 2. Based on environmental factors such as humidity and temperature, the simulation results are more in line with the actual service environment, which significantly improves the accuracy of long-term predictions; 3. An equivalent strength model of the reinforced composite wall was established, which clearly and intuitively shows that the reinforcement scheme can not only significantly improve the initial bearing capacity, but also effectively delay the subsequent degradation rate; 4. The simulation process is implemented using Matlab software. Users only need to input relevant parameters to automatically complete the calculation and visualization output. It is easy to operate and has good universality and promotion value. 5. It can provide important theoretical basis and technical reference for the revision and improvement of existing masonry structure design, appraisal and reinforcement standards, and promote the industry to develop in a more refined and scientific direction.
[0097] The above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for simulating the bearing capacity degradation of unreinforced masonry structures and evaluating the reinforcement effect, characterized in that, include: S1. Construct a physical model of the unreinforced masonry structure, analyze the pressure generated by the vertical load and the shear force generated by the horizontal load, and obtain the compressive bearing capacity and shear bearing capacity index of the masonry structure. S2. Set initial parameters, including material parameters, geometric parameters, environmental parameters and degradation rate parameters, and introduce environmental impact factors to correct the degradation rate parameters; S3. Based on the time decay law and combined with environmental influences, degenerative models of masonry compressive strength and shear strength are constructed respectively. Then, combined with geometric parameters and stability coefficients, time-varying models of compressive bearing capacity and shear bearing capacity are constructed. The degenerative model and the time-varying model are simulated and calculated using programming tools to output the variation law of unreinforced masonry bearing capacity over time. S4. Based on the variation law of unreinforced masonry bearing capacity output in step S3, reinforce the unreinforced masonry wall with reinforcement materials to construct a composite wall, and establish a strength degradation model of the reinforcement material and the original masonry in the composite wall. S5. The equivalent compressive strength and equivalent shear strength of the composite wall are calculated using the area-weighted method. Based on the equivalent compressive strength and equivalent shear strength, a time-varying model of the bearing capacity of the composite wall is constructed. The strength degradation model and time-varying model of the composite wall are simulated and calculated using a programming tool, and the variation law of the bearing capacity of the composite wall over time is output. S6. Compare the variation law of unreinforced masonry bearing capacity output in step S3 with the variation law of composite wall bearing capacity output in step S5.
2. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The calculation unit of the physical model of the unreinforced masonry structure is set to a height of 3m, a thickness of 0.2m, and a length of 1m.
3. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The material parameters include the initial compressive strength of the unreinforced masonry. With initial shear strength ; Among them, initial compressive strength Initial shear strength .
4. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The geometric parameters include the cross-sectional area of the computational unit. With wall height and cross-sectional area , ; The environmental parameters include humidity coefficient. With temperature ,in And the value is truncated to [0.3, 0.99]. .
5. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The degradation rate parameter includes the annual degradation rate of masonry compressive strength. Annual degradation rate of shear strength ,and , ; The formula for calculating the environmental impact factors is as follows: The corrected degradation rate corresponds to the original degradation rate and the environmental impact factor. The product of.
6. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The stability coefficient The calculation formula is: in, The slenderness ratio of an unreinforced masonry member; The degradation model for the compressive strength of masonry is as follows: in, Initial compressive strength, The annual degradation rate of compressive strength, Humidity coefficient; The shear strength degradation model is as follows: in, The initial shear strength, The annual degradation rate of shear strength, This is the humidity coefficient.
7. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The reinforcing material is a concrete slab, and the thickness of the concrete slab is set to 70mm.
8. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The strength degradation model of the reinforcement material includes: a concrete compressive strength degradation model and a concrete shear strength degradation model; specifically including: in, This represents the time-varying value of the concrete compressive strength. This represents the time-varying value of the shear strength of concrete. This refers to the initial compressive strength of the concrete. This refers to the initial shear strength of the concrete. The annual degradation rate of concrete compressive strength; This represents the annual degradation rate of concrete shear strength.
9. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The equivalent strength formula for the composite wall is: Equivalent compressive strength: Equivalent shear strength: in, The projected area of the masonry cross-section; The projected area of the concrete slab cross section; This represents the time-varying value of the masonry compressive strength. This represents the time-varying value of the shear strength of the masonry. This represents the time-varying value of the concrete compressive strength. This represents the time-varying value of the shear strength of concrete.
10. The method for simulating the degradation of bearing capacity of unreinforced masonry structures and evaluating the reinforcement effect according to claim 1, characterized in that, The formula for the bearing capacity of the composite wall is: in, This represents the projected area of the composite wall section. To assess the compressive bearing capacity of the composite wall; This refers to the shear bearing capacity of the composite wall.