North-south flat wide steel box girder bridge transverse temperature gradient model

Abstract

The present application relates to a kind of north-south flat wide steel box girder bridge transverse temperature gradient model, the model is composed of positive temperature gradient model and negative temperature gradient model, wherein positive temperature gradient model is double fold line form, and negative temperature gradient model is three fold line form.For the flat wide steel box girder section characteristics and transverse temperature field distribution characteristics, and the probability distribution of temperature representative value at transverse typical position, the transverse temperature gradient model suitable for the design service life of 200 years flat wide steel box girder bridge is proposed.The transverse temperature gradient model can be used for flat wide steel box girder bridge transverse temperature stress calculation analysis, and can provide reference for the revision of relevant design specification.

Description

Technical Field

[0001] This invention belongs to the field of bridge temperature detection technology, specifically involving a transverse temperature gradient model for a north-south oriented flat wide steel box girder bridge. Background Technology

[0002] Flat steel box girders are a typical closed section, and under the frame effect, the transverse temperature gradient will generate significant transverse temperature stress. Existing research shows that the transverse temperature gradient pattern varies significantly with different main girder cross-sections and different bridge orientations, resulting in different temperature stresses. Therefore, it is necessary to construct transverse and vertical temperature gradient load models applicable to different bridge cross-sections and bridge orientations.

[0003] With the advancement of long-span bridge construction, especially the large-scale application of cable-stayed and suspension bridges, flat steel box girders have become the main girder form. However, bridge design codes currently lack transverse temperature gradient load models for flat steel box girders with different bridge orientations. Therefore, it is necessary to utilize long-term monitoring data of the transverse temperature field of actual bridge flat steel box girders, and consider the influence of bridge orientation, to construct a transverse temperature gradient load model for flat steel box girders to support the calculation and analysis of transverse temperature stress in the main girder. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a transverse temperature gradient model for a north-south oriented flat wide steel box girder bridge.

[0005] The aforementioned transverse temperature gradient model for a north-south oriented, flat, wide steel box girder bridge is derived from the transverse positive temperature gradient model. With the transverse negative temperature gradient model constitute;

[0006] The aforementioned transverse positive temperature gradient model As shown in equation (1):

[0007] In equation (1), This represents the positive temperature gradient at the sunny side, in °C. represents the positive temperature gradient at the shaded side, in °C; x is the distance from the north-south oriented flat wide steel box girder bridge section to the sunny side; L is the width of the north-south oriented flat wide steel box girder bridge. This refers to the design service life of a north-south oriented, flat, wide steel box girder bridge, expressed in years, and can be 100, 150, or 200. for The inverse function of a function for The inverse function of a function Let be the distribution function of the representative value of the positive temperature gradient at the sunny side. Let be the distribution function of the representative value of the positive temperature gradient at the shaded side. , , , , As an intermediate variable;

[0008] The aforementioned transverse negative temperature gradient model As shown in equation (2):

[0009] In equation (2), Distance from the sun The negative temperature gradient at the location is represented by the value in °C. Distance from the shady side The negative temperature gradient at the location is represented by the value in °C, x is the distance from the north-south oriented flat wide steel box girder bridge section to the sunny side, and L is the width of the north-south oriented flat wide steel box girder bridge. The design service life of a north-south oriented, flat, wide steel box girder bridge is given in years. for The inverse function of a function for The inverse function of a function Let be the distribution function representing the negative temperature gradient at the sunny side. Let be the distribution function representing the negative temperature gradient at the shaded side. , , , It is an intermediate variable.

[0010] In equation (1), the stated The value ranges from [0.23, 0.38]. The value of is [1.53, 1.74]. The value ranges from [0.26, 0.43]. The value of is [1.53, 1.77]. In equation (2), the value of is... The value ranges from [-0.67, 0.46]. The value of is [0.24, 0.39]. The value ranges from [-0.95, -0.87]. The value is [0.08, 0.14].

[0011] In equation (1), the stated , , , , The value can be: The best is 100 years. The optimal value is 0.3. The optimal value is 1.63. The optimal value is 0.34. The optimal value is 1.65.

[0012] In equation (2), the stated , , , , The optimal value for is: For 100 years, The optimal value is 0.30. The optimal value is -0.57. The optimal value is 0.11. The optimal value is -0.91.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] This invention utilizes on-site monitoring data of the transverse temperature field of north-south oriented flat steel box girder bridges to construct a transverse temperature gradient model for such bridges. This model can calculate the additional stress and deformation generated by the transverse temperature gradient during the operational phase of north-south oriented flat steel box girder bridges, and can be used for long-life design of north-south oriented flat steel box girder bridges with design service lives of 100, 150, and 200 years. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of a north-south oriented, flat, wide steel box girder bridge.

[0016] Figure 2 It is the distribution of representative temperature values ​​in the transverse positive temperature gradient model of a north-south oriented flat wide steel box girder bridge.

[0017] Figure 3 It is the distribution of representative temperature values ​​in the transverse negative temperature gradient model of a north-south oriented flat wide steel box girder bridge.

[0018] Figure 4 It is a diagram showing the layout of transverse temperature measuring points in the measured temperature field.

[0019] Figure 5 It is the temperature history curve of the measuring point.

[0020] Figure 6 It is the actual measured T HP1 Histogram of positive temperature difference at location.

[0021] Figure 7 It is the actual measured T HP2 Histogram of positive temperature difference at location.

[0022] Figure 8 It is the actual measured T HN1Histogram of negative temperature difference at location.

[0023] Figure 9 It is the actual measured T HN2 Histogram of negative temperature difference at location. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0025] Example 1

[0026] This embodiment relates to a transverse temperature gradient model for a north-south oriented flat wide steel box girder bridge. This model consists of a transverse positive temperature gradient model. With the transverse negative temperature gradient model The structure is as follows: in this embodiment, the west side of the beam cross-section is defined as the sunny side, and the east side of the beam cross-section is defined as the shady side.

[0027] The aforementioned transverse positive temperature gradient model As shown in equation (1):

[0028] In equation (1), This represents the positive temperature gradient at the sunny side, in °C. represents the positive temperature gradient at the shaded side, in °C; x is the distance from the north-south oriented flat wide steel box girder bridge section to the sunny side; L is the width of the north-south oriented flat wide steel box girder bridge. This refers to the design service life of a north-south oriented, flat, wide steel box girder bridge, expressed in years, and can be 100, 150, or 200. for The inverse function of a function for The inverse function of a function Let be the distribution function of the representative value of the positive temperature gradient at the sunny side. Let be the distribution function of the representative value of the positive temperature gradient at the shaded side. To guarantee the rate, , , , As an intermediate variable;

[0029] The aforementioned transverse negative temperature gradient model As shown in equation (2):

[0030] In equation (2), Distance from the sun The negative temperature gradient at the location is represented by the value in °C. Distance from the shady side The negative temperature gradient at the location represents the value, where x is the distance from the north-south oriented flat wide steel box girder bridge section to the sunny side, and L is the width of the north-south oriented flat wide steel box girder bridge. The design service life of a north-south oriented, flat, wide steel box girder bridge is given in years. for The inverse function of a function for The inverse function of a function Let be the distribution function representing the negative temperature gradient at the sunny side. Let be the distribution function representing the negative temperature gradient at the shaded side. , , , It is an intermediate variable.

[0031] This embodiment takes a north-south oriented, flat, wide steel box girder bridge of the Yangtze River in Nanjing as an example, and its three-dimensional cross-section is as follows: Figure 1 As shown, in equation (1), for , for , for , for Based on these parameters, a transverse positive temperature gradient model for a north-south oriented flat wide steel box girder bridge was constructed. The representative temperature values ​​in the transverse positive temperature gradient models corresponding to the 100-year, 150-year, and 200-year design service life are shown in Table 1. The distribution of representative temperature values ​​in the transverse positive temperature gradient model constructed based on these parameters is as follows: Figure 2 As shown.

[0032] Table 1. Representative temperature values ​​in the transverse positive temperature gradient model

[0033] In equation (2), It is -0.57. It is 0.3. for , for Based on these parameters, a corresponding transverse negative temperature gradient model for a north-south oriented flat wide steel box girder bridge was constructed. The representative temperature values ​​in the transverse negative temperature gradient models corresponding to the 100-year, 150-year, and 200-year design service life are shown in Table 2. The distribution of representative temperature values ​​in the transverse negative temperature gradient model constructed according to these parameters is as follows: Figure 3 As shown.

[0034] Table 2. Representative temperature values ​​in the transverse negative temperature gradient model

[0035] Example 2

[0036] The expression for the transverse temperature gradient model of the north-south oriented flat wide steel box girder bridge in this embodiment is the same as that in Embodiment 1, but the representative temperature values ​​are different.

[0037] This embodiment takes a north-south oriented flat wide steel box girder bridge as an example. In equation (1), It is 1.53. It is 0.23. It is 1.53. The value is 0.26. Based on this parameter, a transverse positive temperature gradient model for a north-south oriented flat wide steel box girder bridge was constructed. The representative temperature values ​​in the transverse positive temperature gradient models corresponding to the 100-year, 150-year, and 200-year design service life are shown in Table 3. The distribution of representative temperature values ​​in the transverse positive temperature gradient model constructed according to this parameter is as follows: Figure 2 As shown.

[0038] Table 3. Representative temperature values ​​in the transverse positive temperature gradient model

[0039] In equation (2), It is -0.67. It is 0.24. It is -0.95. The value is 0.08. Based on this parameter, a corresponding transverse negative temperature gradient model for a north-south oriented flat wide steel box girder bridge was constructed. The representative temperature values ​​in the transverse negative temperature gradient models corresponding to the 100-year, 150-year, and 200-year design service life are shown in Table 4. The distribution of representative temperature values ​​in the transverse negative temperature gradient model constructed according to this parameter is as follows: Figure 3 As shown.

[0040] Table 4. Representative temperature values ​​in the transverse negative temperature gradient model

[0041] Example 3

[0042] The expression for the transverse temperature gradient model of the north-south oriented flat wide steel box girder bridge in this embodiment is the same as that in Embodiment 1, but the representative temperature values ​​are different.

[0043] This embodiment takes a north-south oriented flat wide steel box girder bridge as an example. In equation (1), It is 1.74. It is 0.38. It is 1.77. The value is 0.43. Based on this parameter, a transverse positive temperature gradient model for a north-south oriented flat wide steel box girder bridge was constructed. The representative temperature values ​​in the transverse positive temperature gradient models corresponding to the 100-year, 150-year, and 200-year design service life are shown in Table 5. The distribution of representative temperature values ​​in the transverse positive temperature gradient model constructed according to this parameter is as follows: Figure 2 As shown.

[0044] Table 5. Representative temperature values ​​in the transverse positive temperature gradient model

[0045] In equation (2), It is 0.46. It is 0.39. It is -0.87. The value is 0.14. Based on this parameter, a corresponding transverse negative temperature gradient model for a north-south oriented flat wide steel box girder bridge is constructed. The representative temperature values ​​in the transverse negative temperature gradient models corresponding to the 100-year, 150-year, and 200-year design service life are shown in Table 6. The distribution of representative temperature values ​​in the transverse negative temperature gradient model constructed according to this parameter is as follows: Figure 3 As shown.

[0046] Table 6. Representative temperature values ​​in the transverse negative temperature gradient model

[0047] Experiment 1

[0048] To verify the effectiveness of the transverse positive temperature gradient model for a north-south oriented flat, wide steel box girder bridge, the inventors deployed transverse temperature sensors on the Nanjing Yangtze River Bridge and conducted long-term temperature field monitoring. The specific construction process is as follows:

[0049] I. Long-term monitoring equipment

[0050] The monitoring equipment is a Donghua DH2002 remote temperature acquisition instrument produced in Taizhou, Jiangsu Province, and the temperature measuring points use three-wire Pt100 sensors.

[0051] II. Arrangement of Temperature Measurement Points

[0052] Temperature measuring points were selected on the top slab of the flat steel box girder bridge. A coordinate system was established with the sunny side edge of the top slab as the origin. The arrangement principle for the temperature measuring points on the top slab was as follows: with the sunny side edge of the top slab as the origin, temperature measuring points were arranged along the width of the top slab. The locations of the measuring points were expressed as horizontal distances from the origin as 0.00m, 5.60m, 12.70m, 16.55m, 20.40m, 27.50m, and 33.10m, respectively. Figure 4 As shown, the data collection interval is 1 minute.

[0053] III. Analysis of the Effect of the Lateral Positive Temperature Gradient Load Model

[0054] In the transverse positive temperature gradient model of a north-south oriented flat wide steel box girder bridge, T HP1 and T HP2 Taking a location as an example, a temperature history curve for the measuring point is plotted based on actual temperature monitoring data, such as... Figure 5 As shown. Calculate T respectively. HP1 and T HP2 The temperature difference between the location and the location with the lowest average temperature at the measuring points on the box girder section is used as the basis for plotting a probability density histogram and fitting a probability density function, as shown below. Figure 6 and Figure 7 As shown. Values ​​were taken for the 99% upper guarantee rate in the probability density function, and the resulting T values ​​were obtained. HP1 and T HP2 The temperature gradients at these locations are represented by values ​​of 9.8℃ and 10.2℃, respectively.

[0055] A temperature gradient model corresponding to a 100-year design service life was constructed using a transverse positive temperature gradient model of a north-south oriented flat wide steel box girder bridge. for , for , for , for T was calculated. HP1 and T HP2 The values ​​were 10.2℃ and 10.6℃, which are not significantly different from the measured results. This experiment shows that the transverse positive temperature gradient model has good applicability.

[0056] Experiment 2

[0057] To verify the effectiveness of the transverse negative temperature gradient model for a north-south oriented flat, wide steel box girder, the inventors deployed transverse temperature sensors on the Nanjing Yangtze River Bridge and conducted long-term temperature field monitoring. The specific construction process is as follows:

[0058] I. Long-term monitoring equipment

[0059] Consistent with Experiment 1.

[0060] II. Arrangement of Temperature Measurement Points

[0061] Consistent with Experiment 1.

[0062] III. Analysis of the Effect of the Lateral Negative Temperature Gradient Load Model

[0063] In the transverse negative temperature gradient model of a north-south oriented flat wide steel box girder bridge, T HN1 and T HN2 Taking a specific location as an example, a temperature history curve for the measuring point is plotted based on actual temperature monitoring data. T is calculated respectively.HN1 and T HN2 The temperature difference between the location and the location with the highest average temperature at the measuring point on the box girder section is used as the basis for plotting a probability density histogram and fitting a probability density function, as shown below. Figure 8 and Figure 9 As shown. The values ​​of T are obtained by taking values ​​for the 1% upper guarantee rate in the probability density function. HN1 and T HN2 The temperature gradients at these locations represent -2.1℃ and -2.2℃, respectively.

[0064] A temperature gradient model corresponding to a 100-year design service life was constructed using a negative transverse temperature gradient model of a north-south oriented flat wide steel box girder bridge. It is -0.57. It is 0.3. for , for T was calculated. HN1 and T HN2 The values ​​were -2.4℃ and -2.4℃. This experiment demonstrates that the transverse negative temperature gradient model has good applicability.

Claims

1. A transverse temperature gradient model for a north-south oriented, flat, wide steel box girder bridge, characterized in that: This model is based on the transverse positive temperature gradient model. With the transverse negative temperature gradient model constitute; The aforementioned transverse positive temperature gradient model as follows: In equation (1), This represents the positive temperature gradient at the sunny side, in °C. represents the positive temperature gradient at the shaded side, in °C; x is the distance from the north-south oriented flat wide steel box girder bridge section to the sunny side; L is the width of the north-south oriented flat wide steel box girder bridge. This refers to the design service life of a north-south oriented, flat, wide steel box girder bridge, expressed in years, and can be 100, 150, or 200. for The inverse function of a function for The inverse function of a function Let be the distribution function of the representative value of the positive temperature gradient at the sunny side. Let be the distribution function of the representative value of the positive temperature gradient at the shaded side. , , , , As an intermediate variable; The aforementioned transverse negative temperature gradient model as follows: In equation (2), Distance from the sun The negative temperature gradient at the location is represented by the value in °C. Distance from the shady side The negative temperature gradient at the location is represented by the value in °C, x is the distance from the north-south oriented flat wide steel box girder bridge section to the sunny side, and L is the width of the north-south oriented flat wide steel box girder bridge. The design service life of a north-south oriented, flat, wide steel box girder bridge is given in years. for The inverse function of a function for The inverse function of a function Let be the distribution function representing the negative temperature gradient at the sunny side. Let be the distribution function representing the negative temperature gradient at the shaded side. , , , It is an intermediate variable.

2. The transverse temperature gradient model for a north-south oriented flat wide steel box girder bridge according to claim 1, characterized in that: In equation (1), the stated The value ranges from [0.23, 0.38]. The value of is [1.53, 1.74]. The value ranges from [0.26, 0.43]. The value of is [1.53, 1.77]. In equation (2), the value of is... The value ranges from [-0.67, 0.46]. The value of is [0.24, 0.39]. The value ranges from [-0.95, -0.87]. The value is [0.08, 0.14].

3. The transverse temperature gradient model for a north-south oriented flat wide steel box girder bridge according to claim 1, characterized in that... In equation (1), the stated , , , , The value can be: For 100 years, It is 0.

3. It is 1.

63. It is 0.

34. It is 1.

65.

4. The transverse temperature gradient model for a north-south oriented flat wide steel box girder bridge according to claim 1, characterized in that... In equation (2), the stated , , , , The value can be: For 100 years, It is 0.

30. It is -0.

57. It is 0.

11. It is -0.91.

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