Bridge sunshine temperature field simulation method

Abstract

The application discloses a bridge sunshine temperature field simulation method, comprising the following steps: creating a bridge BIM model in Revit software; performing solar radiation analysis according to the BIM model to obtain a sunshine field; importing geometric information of the bridge BIM model and the sunshine field into a finite element analysis platform to perform finite element analysis and obtain a bridge three-dimensional temperature field. The application has the beneficial effect of improving the calculation precision of the bridge temperature field.

Description

Technical Field

[0001] This invention relates to the field of bridge simulation technology, and in particular to a method for simulating the solar radiation temperature field of bridges. Background Technology

[0002] Bridges are constantly exposed to the natural environment, enduring intense temperature fluctuations and solar radiation. This leads to uneven temperature distribution within the bridge structure, resulting in significant thermal stress. Extensive theoretical analysis and bridge monitoring data indicate that thermal stress constitutes a large proportion of bridge design loads. In long-span prestressed concrete box girder bridges, especially in statically indeterminate structural systems, thermal stress can reach or even exceed the stress caused by vehicle live loads. Therefore, temperature effects pose a significant threat to the service life and operational safety of bridge structures.

[0003] The solar temperature field of bridges is influenced by various factors, including climate conditions, bridge location, bridge orientation, and its own structural design. For example, current Chinese design codes only consider a one-dimensional vertical temperature gradient and do not account for the differences in temperature gradient curves across different regions and climate zones. An inaccurate temperature field can underestimate the actual load-bearing capacity of the bridge, thus increasing the risk of cracking. Furthermore, some studies have shown that the lateral temperature gradient effect is not negligible for high-pier, long-span continuous rigid frame bridges. The lateral temperature gradient is mainly caused by solar radiation reaching the web of the box girder, and bridge webs with different orientations have different solar radiation values, resulting in different temperature fields. In addition, due to the bridge's own shading, some bridge surfaces will cast shadows under sunlight. If the influence of solar shading is not considered when analyzing the temperature field, a significant error will occur between the analytical results and the measured results.

[0004] Current bridge temperature field simulation methods only consider one or a few of the aforementioned influencing factors; no method can yet account for all of them. Over the past decade, BIM technology, characterized by informatization and digitalization, has been bringing about an unprecedented transformation to the construction industry, with an increasing number of projects benefiting from its application. The wealth of fundamental information contained in BIM models and the core concept of information sharing advocated by BIM technology offer new avenues for bridge temperature field simulation. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a novel method for simulating the temperature field of bridges. This method utilizes information from a BIM model (location, elevation, geometric information, etc.), taking meteorological data as input. By performing solar radiation analysis on the bridge, the solar radiation field on the bridge surface is accurately obtained. The solar radiation field and meteorological data are then applied as thermal loads and thermal boundary conditions to a finite element thermal analysis model, and solving this model yields the bridge's solar radiation temperature field. This method allows for the determination of a "personalized" temperature field (or temperature gradient model) for the bridge, providing a basis for calculating the temperature effects on the bridge.

[0006] This invention provides a method for simulating the solar radiation temperature field of a bridge, comprising the following steps:

[0007] S1. Create a bridge BIM model in Revit software;

[0008] S2. Perform solar radiation analysis based on the BIM model to obtain the solar radiation field;

[0009] S3. Import the geometric information and solar radiation field of the bridge BIM model into the finite element analysis platform, perform finite element analysis, and obtain the three-dimensional temperature field of the bridge.

[0010] Furthermore, in step S1, the bridge BIM model includes: bridge geometric information, location information, and orientation information.

[0011] Furthermore, step S2 specifically includes:

[0012] S21. Obtain local weather data for the bridge;

[0013] S22. Use the BIM solar radiation analysis tool to call up the bridge BIM model and obtain the analysis surface and shading surface in the bridge geometry information;

[0014] S23. Set the time study range and the grid spacing of the analysis points on the analysis surface;

[0015] S24. Based on the analysis surface, shading surface, time study range, analysis point grid spacing, and local weather files of the bridge, generate a solar radiation field using BIM solar radiation analysis tools; the solar radiation field includes hourly solar radiation data and corresponding analysis point coordinates.

[0016] Furthermore, step S3 specifically includes:

[0017] S31. Import the geometric information of the bridge BIM model into the finite element analysis platform;

[0018] S32. In the finite element analysis platform, the geometric information is meshed, analysis steps are created, thermal loads are applied, and boundary conditions are created to finally construct the finite element model.

[0019] S33. Solve the finite element model to obtain the three-dimensional temperature field of the bridge.

[0020] Furthermore, during the application of thermal load in step S32, the solar radiation field is applied to the surface of the bridge finite element model in a mapped manner as heat flux density.

[0021] The boundary conditions in step S32 are created based on hourly meteorological data in the local weather file of the bridge.

[0022] The beneficial effects provided by this invention are:

[0023] (1) This method utilizes the information sharing feature of BIM technology. The geometric, location, and orientation information in the bridge BIM model can be used for BIM sunlight simulation, and the geometric information can also be used for geometric modeling of the finite element model.

[0024] (2) Solar radiation analysis can realistically simulate the shading relationship between structures, thereby accurately obtaining the solar radiation field on the bridge surface based on weather data files. This solar radiation field accurately reflects the distribution of solar radiation heat flow on the bridge surface, which is an important condition for obtaining the real temperature field.

[0025] (3) The boundary conditions for bridge thermal analysis are derived from weather data, ensuring that the calculated results of the bridge temperature field are close to reality. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0028] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the method flow of the present invention; a method for simulating the solar radiation temperature field of a bridge, comprising the following:

[0029] S1. Create a bridge BIM model in Revit software;

[0030] It should be noted that a complete BIM model contains a lot of design information. For this application, the bridge BIM model must include the following information: bridge geometry, bridge location information (geographic latitude and longitude), and bridge orientation (the geometric model can be placed according to its actual orientation).

[0031] S2. Perform solar radiation analysis based on the BIM model to obtain the solar radiation field;

[0032] It should be noted that the main purpose of step S2 is to use BIM solar radiation analysis tools to extract BIM model information and weather data to generate the solar radiation field. The specific operation process is as follows:

[0033] S21. Obtain local weather data for the bridge;

[0034] As one example, the main process for obtaining weather files is as follows: First, the weather file is edited. This method requires a weather file in WEA format. The weather file can be edited based on an existing WEA file using measured meteorological data, or it can be edited from an EPW file (a common meteorological file format for energy consumption analysis) based on measured meteorological records and then converted into a WEA file (this can be done using the EnergyPlus format conversion tool).

[0035] It should be noted that the meteorological data in WEA weather files is hourly data.

[0036] S22. Use the BIM solar radiation analysis tool to call up the bridge BIM model and obtain the analysis surface and shading surface in the bridge geometry information;

[0037] As one example, the tool for performing solar radiation analysis is the Dynamo visualization programming tool in Autodesk Revit, which utilizes the officially provided node package called "Solar Analysis".

[0038] It should be noted that the analysis surface is the surface on which the solar radiation field is to be generated; the occlusion surface is the surface that occludes the analysis surface.

[0039] S23. Set the time study range and the grid spacing of the analysis points on the analysis surface;

[0040] It should be noted that the time study range should be set as a time period, such as the average solar radiation (in W / m²) generated from 10:00 AM to 11:00 AM on March 4, 2013, on the analyzed surface. 2 The grid spacing of the analysis points can be set according to the user's needs. The denser the spacing, the more detailed the results, but the longer the calculation time.

[0041] S24. Based on the analysis surface, shading surface, time study range, analysis point grid spacing, and local weather file of the bridge, generate a solar radiation field using BIM solar radiation analysis tools; the solar radiation field includes hourly solar radiation data and corresponding analysis point coordinates.

[0042] It should be noted that changing the analysis time period in 1-hour increments can generate hourly solar radiation data for the entire study period; this step is accomplished in Dynamo using DesignScript programming.

[0043] It should be further noted that the solar radiation field data from the solar radiation analysis were exported as a CSV file using DesignScript programming.

[0044] S3. Import the geometric information and solar radiation field of the bridge BIM model into the finite element analysis platform, perform finite element analysis, and obtain the three-dimensional temperature field of the bridge.

[0045] Step S3 is as follows:

[0046] S31. Import the geometric information of the bridge BIM model into the finite element analysis platform;

[0047] S32. In the finite element analysis platform, the geometric information is meshed, analysis steps are created, thermal loads are applied, and boundary conditions are created to finally construct the finite element model.

[0048] S33. Solve the finite element model to obtain the three-dimensional temperature field of the bridge.

[0049] It should be noted that step S3 mainly involves establishing a finite element model in the finite element analysis platform and solving for the temperature field. The finite element modeling process can be completed manually or automatically through programming.

[0050] As an example, the Abaqus finite element analysis platform is used as an example. First, the geometric model created in Revit is imported into Abaqus in SAT format. The imported geometric model is translated and rotated to a position that is completely consistent with that in Revit (to ensure that the spatial coordinates of the bridge are consistent in Abaqus and Revit). Then, the geometric model is meshed, analysis steps are created, thermal loads are applied, and boundary conditions are created.

[0051] The analysis step increment should be consistent with the previous solar radiation analysis increment (i.e., 1 hour);

[0052] When applying the heat load, the solar radiation field in the CSV file generated in the previous step is mapped to the surface of the bridge finite element model in Abaqus according to the coordinate points.

[0053] The creation of thermal boundary conditions is based on hourly meteorological data (such as temperature and wind speed) in the local weather file of the bridge from the previous step.

[0054] Once the finite element model is built, the three-dimensional temperature field of the bridge can be generated by solving it in Abaqus.

[0055] The beneficial effects of this invention are:

[0056] (1) This method utilizes the information sharing feature of BIM technology. The geometric, location, and orientation information in the bridge BIM model can be used for BIM solar simulation, and the geometric information can also be used for geometric modeling of the finite element model.

[0057] (2) Solar radiation analysis can realistically simulate the shading relationship between structures, thereby accurately obtaining the solar radiation field on the bridge surface based on weather data files. This solar radiation field accurately reflects the distribution of solar radiation heat flow on the bridge surface, which is an important condition for obtaining the real temperature field.

[0058] (3) The boundary conditions for bridge thermal analysis are derived from weather data, ensuring that the calculated results of the bridge temperature field are close to reality.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for simulating the solar radiation temperature field of a bridge, characterized in that: Includes the following steps: S1. Create a bridge BIM model in Revit software; S2. Perform solar radiation analysis based on the BIM model to obtain the solar radiation field; S3. Import the geometric information and solar radiation field of the bridge BIM model into the finite element analysis platform, perform finite element analysis, and obtain the three-dimensional temperature field of the bridge. In step S1, the bridge BIM model includes: bridge geometric information, location information, and orientation information; Step S2 is as follows: S21. Obtain local weather data for the bridge; S22. Use the BIM solar radiation analysis tool to call up the bridge BIM model and obtain the analysis surface and shading surface in the bridge geometry information; S23. Set the time study range and the grid spacing of the analysis points on the analysis surface; S24. Based on the analysis surface, shading surface, time study range, analysis point grid spacing, and local weather file of the bridge, generate a solar radiation field using BIM solar radiation analysis tools; the solar radiation field includes hourly solar radiation data and corresponding analysis point coordinates. Step S3 is as follows: S31. Import the geometric information of the bridge BIM model into the finite element analysis platform; S32. In the finite element analysis platform, the geometric information is meshed, analysis steps are created, thermal loads are applied, and boundary conditions are created to finally construct the finite element model. S33. Solve the finite element model to obtain the three-dimensional temperature field of the bridge; When applying the heat load in step S32, the solar radiation field is applied to the surface of the bridge finite element model in a mapped manner as the heat flux density.

2. The bridge solar radiation temperature field simulation method as described in claim 1, characterized in that: The boundary conditions in step S32 are created based on hourly meteorological data.

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