Transverse temperature gradient model of flat wide steel box girder bridge in north-south direction

Abstract

The invention relates to a south-north direction flat wide steel box girder bridge transverse temperature gradient model which is composed of a positive temperature gradient model and a negative temperature gradient model, the positive temperature gradient model is in a double-broken-line form, and the negative temperature gradient model is in a three-broken-line form. According to section characteristics and transverse temperature field distribution characteristics of the flat wide steel box girder and probability distribution of temperature representative values at typical transverse positions, a transverse temperature gradient model suitable for designing the flat wide steel box girder bridge with the service life of 200 years is provided. The transverse temperature gradient model can be used for calculating and analyzing the transverse temperature stress of the flat wide steel box girder bridge, and reference can be provided for revision of relevant design specifications.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge temperature detection, and in particular relates to a transverse temperature gradient model of a north-south flat wide steel box girder bridge. Background Art

[0002] Flat steel box girder is a typical closed section. Under the action of frame effect, the transverse temperature gradient will produce large transverse temperature stress. Existing studies have shown that the transverse temperature gradient forms are significantly different for different main beam cross-section forms and different bridge positions, and the resulting temperature stresses are also different. Therefore, it is necessary to construct a transverse and vertical temperature gradient load model suitable for different bridge cross-section forms and bridge positions.

[0003] With the advancement of long-span bridge construction, especially the large-scale application of cable-stayed bridges and suspension bridges, flat steel box girders are the main girder form used. However, there is no transverse temperature gradient load model for flat steel box girders with different bridge positions in the bridge design specifications. Therefore, it is necessary to use the long-term monitoring data of the transverse temperature field of flat steel box girders of real bridges, and consider the influence of the bridge position to construct a transverse temperature gradient load model for flat steel box girders to support the calculation and analysis of the transverse temperature stress of 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 flat wide steel box girder bridge.

[0005] The transverse temperature gradient model of the above north-south flat wide steel box girder bridge is composed of the transverse positive temperature gradient model T HP (x) and the lateral negative temperature gradient model T HN (x) composition;

[0006] The transverse positive temperature gradient model T HP (x) is as shown in formula (1):

[0007]

[0008] In formula (1), T HP1 is the representative value of the positive temperature gradient at the sun side, in °C, T HP2 is the representative value of the positive temperature gradient at the shady side, in °C, x is the distance from the north-south flat wide steel box girder bridge section to the sunny side, L is the width of the north-south flat wide steel box girder bridge, Ν d It is the design service life of the north-south flat wide steel box girder bridge, in years, with a value of 100, 150 or 200. F HP1 (α) is the inverse function of the function, F HP2 (α) The inverse function, F HP1(α) is the distribution function of the representative value of the positive temperature gradient at the positive side, F HP2 (α) is the distribution function of the representative value of the positive temperature gradient at the shadow side, α, σ HP1 , μ HP1 , σ HP2 , μ HP2 is an intermediate variable;

[0009] The lateral negative temperature gradient model T HN (x) is shown in formula (2):

[0010]

[0011] In formula (2), T HN1 is the representative value of the negative temperature gradient at the positive side, in °C, T HN2 is the representative value of the negative temperature gradient at the shady side, in °C, x is the distance from the north-south flat wide steel box girder bridge section to the sunny side, L is the width of the north-south flat wide steel box girder bridge, Ν d It is the design service life of the north-south flat wide steel box girder bridge, in years. F HN1 (α) is the inverse function of the function, F HN2 (α) The inverse function, F HN1 (α) is the distribution function of the representative value of the negative temperature gradient at the positive side, F HN2 (α) is the distribution function of the representative value of the negative temperature gradient at the shadow side, μ HN1 , σ HN1 , μ HN2 , σ HN2 is an intermediate variable.

[0012] In formula (1), the σ HP1 The value of is [0.23,0.38], μ HP1 The value of is [1.53,1.74], σ HP2 The value of is [0.26, 0.43], μ HP2 The value of is [1.53,1.77]. In formula (2), the μ HN1 The value of is [-0.67, 0.46], σ HN1 The value of is [0.24,0.39], μ HN2 The value of is [-0.95,-0.87], σ HN2 The value of is [0.08,0.14].

[0013] In formula (1), N d , σ HP1 , μ HP1 , σHP2 , μ HP2 The value of is: d The best is 100 years, σ HP1 The best is 0.3, μ HP1 The best value is 1.63, σ HP2 The best is 0.34, μ HP2 The best is 1.65.

[0014] In formula (2), N d , σ HN1 , μ HN1 , σ HN2 , μ HN2 The best value of is: d is 100 years, σ HN1 The best value is 0.30, μ HN1 The best is -0.57, σ HN2 The best is 0.11, μ HN2 The best is -0.91.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The present invention uses the on-site transverse temperature field monitoring data of the north-south flat steel box girder bridge to construct a transverse temperature gradient model of the north-south flat steel box girder bridge. It can calculate the additional stress and deformation caused by the transverse temperature gradient of the north-south flat steel box girder bridge during the operation stage, and can be used for the long-life design of the north-south flat steel box girder bridge with a design service life of 100, 150 and 200 years. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view of a north-south flat wide steel box girder bridge.

[0018] Figure 2 It is the representative value distribution of the transverse positive temperature gradient model temperature of the north-south flat wide steel box girder bridge.

[0019] Figure 3 It is the representative value distribution of the temperature in the transverse negative temperature gradient model of the north-south flat wide steel box girder bridge.

[0020] Figure 4 It is the layout diagram of the transverse temperature measuring points of the measured temperature field.

[0021] Figure 5 It is the temperature history curve of the measuring point.

[0022] Figure 6 It is the measured T HP1 Histogram of positive temperature difference statistics at locations.

[0023] Figure 7 It is the measured T HP2Histogram of positive temperature difference statistics at locations.

[0024] Figure 8 It is the measured T HN1 Histogram of negative temperature difference statistics at locations.

[0025] Fig. 9 It is the measured T HN2 Histogram of negative temperature difference statistics at locations. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings and examples, but the present invention is not limited to the following embodiments.

[0027] Example 1

[0028] This embodiment involves a transverse temperature gradient model of a north-south flat wide steel box girder bridge, which is composed of a transverse positive temperature gradient model T HP (x) and the lateral negative temperature gradient model T HN (x) structure, wherein, in this embodiment, the west side of the beam cross section is defined as the positive side, and the east side of the beam cross section is defined as the negative side.

[0029] The transverse positive temperature gradient model T HP (x) is as shown in formula (1):

[0030]

[0031] In formula (1), T HP1 is the representative value of the positive temperature gradient at the sun side, in °C, T HP2 is the representative value of the positive temperature gradient at the shady side, in °C, x is the distance from the north-south flat wide steel box girder bridge section to the sunny side, L is the width of the north-south flat wide steel box girder bridge, Ν d It is the design service life of the north-south flat wide steel box girder bridge, in years, with a value of 100, 150 or 200. F HP1 (α) is the inverse function of the function, F HP2 (α) The inverse function, F HP1 (α) is the distribution function of the representative value of the positive temperature gradient at the positive side, F HP2 (α) is the distribution function of the representative value of the positive temperature gradient at the shadow side, α is the guarantee rate, σ HP1 , μ HP1 , σ HP2 , μ HP2 is an intermediate variable;

[0032] The lateral negative temperature gradient model T HN (x) is shown in formula (2):

[0033]

[0034] In formula (2), T HN1 is the representative value of the negative temperature gradient at the positive side, in °C, T HN2 is the representative value of the negative temperature gradient at the shady side, in °C, x is the distance from the north-south flat wide steel box girder bridge section to the sunny side, L is the width of the north-south flat wide steel box girder bridge, Ν d It is the design service life of the north-south flat wide steel box girder bridge, in years. F HN1 (α) is the inverse function of the function, F HN2 (α) The inverse function, F HN1 (α) is the distribution function of the representative value of the negative temperature gradient at the positive side, F HN2 (α) is the distribution function of the representative value of the negative temperature gradient at the shadow side, μ HN1 , σ HN1 , μ HN2 , σ HN2 is an intermediate variable.

[0035] This embodiment takes a north-south flat wide steel box girder bridge of a Yangtze River bridge in Nanjing as an example. Its three-dimensional cross section is as follows: Figure 1 As shown in formula (1), μ HP1 is 1.63, σ HP1 is 0.3, μ HP2 is 1.65, σ HP2 =0.34, and the corresponding transverse positive temperature gradient model of the north-south flat wide steel box girder bridge is constructed according to this parameter. The temperature representative values ​​in the transverse positive temperature gradient model corresponding to the design service life of 100 years, 150 years, and 200 years are shown in Table 1. The temperature representative value distribution of the transverse positive temperature gradient model constructed according to this parameter is shown in Figure 2 shown.

[0036] Table 1 Representative values ​​of temperature in the transverse positive temperature gradient model

[0037]

[0038] In formula (2), μ HN1 is -0.57, σ HN1 is 0.3, μ HN2 is -0.91, σ HN2 =0.11, and the corresponding transverse negative temperature gradient model of the north-south flat wide steel box girder bridge is constructed according to this parameter. The temperature representative values ​​in the transverse negative temperature gradient model corresponding to the design service life of 100 years, 150 years, and 200 years are shown in Table 2. The temperature representative value distribution of the transverse negative temperature gradient model constructed according to this parameter is shown in Figure 3 shown.

[0039] Table 2 Representative values ​​of temperature in the lateral negative temperature gradient model

[0040]

[0041] Example 2

[0042] The expression of the transverse temperature gradient model of the north-south flat wide steel box girder bridge involved in this embodiment is the same as that in Example 1, but the temperature representative value is different.

[0043] This embodiment takes a north-south flat wide steel box girder bridge as an example. In formula (1), μ HP1 is 1.53, σ HP1 is 0.23, μ HP2 is 1.53, σ HP2 =0.26, and the corresponding transverse positive temperature gradient model of the north-south flat wide steel box girder bridge is constructed according to this parameter. The temperature representative values ​​in the transverse positive temperature gradient model corresponding to the design service life of 100 years, 150 years, and 200 years are shown in Table 3. The temperature representative value distribution of the transverse positive temperature gradient model constructed according to this parameter is shown in Figure 2 shown.

[0044] Table 3 Representative values ​​of temperature in the transverse positive temperature gradient model

[0045]

[0046] In formula (2), μ HN1 is -0.67, σ HN1 is 0.24, μ HN2 is -0.95, σ HN2 =0.08, and the corresponding transverse negative temperature gradient model of the north-south flat wide steel box girder bridge is constructed according to this parameter. The temperature representative values ​​in the transverse negative temperature gradient model corresponding to the design service life of 100 years, 150 years, and 200 years are shown in Table 4. The temperature representative value distribution of the transverse negative temperature gradient model constructed according to this parameter is shown in Figure 3 shown.

[0047] Table 4 Representative values ​​of temperature in the lateral negative temperature gradient model

[0048]

[0049] Example 3

[0050] The expression of the transverse temperature gradient model of the north-south flat wide steel box girder bridge involved in this embodiment is the same as that in Example 1, but the temperature representative value is different.

[0051] This embodiment takes a north-south flat wide steel box girder bridge as an example. In formula (1), μ HP1 is 1.74, σ HP1 is 0.38, μ HP2 is 1.77, σ HP2 =0.43, and the corresponding transverse positive temperature gradient model of the north-south flat wide steel box girder bridge is constructed according to this parameter. The temperature representative values ​​in the transverse positive temperature gradient model corresponding to the design service life of 100 years, 150 years, and 200 years are shown in Table 5. The temperature representative value distribution of the transverse positive temperature gradient model constructed according to this parameter is shown in Figure 2 shown.

[0052] Table 5 Representative values ​​of temperature in the transverse positive temperature gradient model

[0053]

[0054] In formula (2), μ HN1 is 0.46, σ HN1 is 0.39, μ HN2 is -0.87, σ HN2 =0.14, and the corresponding transverse negative temperature gradient model of the north-south flat wide steel box girder bridge is constructed according to this parameter. The temperature representative values ​​in the transverse negative temperature gradient model corresponding to the design service life of 100 years, 150 years, and 200 years are shown in Table 6. The temperature representative value distribution of the transverse negative temperature gradient model constructed according to this parameter is shown in Figure 3 shown.

[0055] Table 6 Representative values ​​of temperature in the lateral negative temperature gradient model

[0056]

[0057] Test 1

[0058] In order to verify the effect of the transverse positive temperature gradient model of the north-south flat wide steel box girder bridge, the inventors arranged transverse temperature sensors on the Nanjing Yangtze River Bridge and conducted long-term temperature field monitoring. The specific construction process is as follows:

[0059] 1. Long-term monitoring equipment

[0060] The monitoring equipment is the Donghua DH2002 remote temperature acquisition instrument produced in Taizhou, Jiangsu, and the temperature measurement point uses a three-wire Pt100 sensor.

[0061] 2. Temperature measurement point arrangement

[0062] The flat steel box girder bridge top plate is selected to arrange the temperature measuring points, and the coordinate system is established with the positive side edge of the flat steel box girder bridge top plate as the coordinate origin. The arrangement principle of the temperature measuring points on the flat steel box girder bridge top plate is as follows: the positive side edge of the top plate is taken as the coordinate origin, and the temperature measuring points are arranged in the width direction of the top plate. The positions of the measuring points are expressed as 0.00m, 5.60m, 12.70m, 16.55m, 20.40m, 27.50m, and 33.10m from the coordinate origin. Figure 4 As shown, the acquisition interval is 1 minute.

[0063] 3. Analysis of the effect of the transverse positive temperature gradient load model

[0064] In the model of positive transverse temperature gradient of north-south flat wide steel box girder bridge, T HP1 and T HP2 Taking the location as an example, the temperature history curve of the measuring point is drawn based on the actual temperature monitoring data, such as Figure 5 As shown. Calculate T HP1 and T HP2 The temperature difference between the position and the position where the average temperature of the box girder section measuring point is the lowest, and a probability density histogram is drawn based on the data and a probability density function is fitted, as shown in the figure. Figure 6 and Figure 7 As shown. The 99% upper guarantee rate in the probability density function is taken as the value, and the obtained T HP1 and T HP2 The representative values ​​of temperature gradient at the locations are 9.8°C and 10.2°C respectively.

[0065] The temperature gradient model corresponding to the 100-year design service life is constructed using the transverse positive temperature gradient model of the north-south flat wide steel box girder bridge. HP1 is 1.63, σ HP1 is 0.3, μ HP2 is 1.65, σ HP2 is 0.34, and T HP1 and T HP2 The results are 10.2℃ and 10.6℃, which are slightly different from the measured results. This experiment shows that the lateral positive temperature gradient model has good applicability.

[0066] Test 2

[0067] In order to verify the effect of the transverse negative temperature gradient model of the north-south flat wide steel box girder, the inventors arranged transverse temperature sensors on the Nanjing Yangtze River Bridge and conducted long-term temperature field monitoring. The specific construction process is as follows:

[0068] 1. Long-term monitoring equipment

[0069] Same as Experiment 1.

[0070] 2. Temperature measurement point arrangement

[0071] Same as Experiment 1.

[0072] 3. Analysis of the effect of the lateral negative temperature gradient load model

[0073] The transverse negative temperature gradient model of a north-south flat wide steel box girder bridge is shown in Figure 2. HN1 and T HN2 Taking the location as an example, the temperature history curve of the measuring point is drawn based on the actual temperature monitoring data. Calculate T HN1 and T HN2 The temperature difference between the position and the position with the highest average temperature of the box girder section measuring point is plotted based on the data and the probability density function is fitted, as shown in Figure 8 and Fig. 9 As shown. The upper guarantee rate of 1% in the probability density function is taken as the value, and the obtained T HN1 and T HN2 The representative values ​​of temperature gradients at the locations are -2.1°C and -2.2°C respectively.

[0074] The temperature gradient model corresponding to the 100-year design service life is constructed using the transverse negative temperature gradient model of the north-south flat wide steel box girder bridge. HN1 is -0.57, σ HN1 is 0.3, μ HN2 is -0.91, σ HN2 is 0.11, and T HN1 and T HN2 The experiment shows that the lateral negative temperature gradient model has good applicability.

Claims

1. A transverse temperature gradient model for a north-south flat wide steel box girder bridge, characterized by: The model consists of a transverse positive temperature gradient model T HP (x) and the lateral negative temperature gradient model T HN (x) composition; The transverse positive temperature gradient model T HP (x) are as follows: In formula (1), T HP1 is the representative value of the positive temperature gradient at the sun side, in °C, T HP2 is the representative value of the positive temperature gradient at the shady side, in °C, x is the distance from the north-south flat wide steel box girder bridge section to the sunny side, L is the width of the north-south flat wide steel box girder bridge, Ν d It is the design service life of the north-south flat wide steel box girder bridge, in years, with a value of 100, 150 or 200. F HP1 (α) is the inverse function of the function, F HP2 (α) The inverse function, F HP1 (α) is the distribution function of the representative value of the positive temperature gradient at the positive side, F HP2 (α) is the distribution function of the representative value of the positive temperature gradient at the shadow side, α, σ HP1 , μ HP1 , σ HP2 , μ HP2 is an intermediate variable; The lateral negative temperature gradient model T HN (x) are as follows: In formula (2), T HN1 is the representative value of the negative temperature gradient at the positive side, in °C, T HN2 is the representative value of the negative temperature gradient at the shady side, in °C, x is the distance from the north-south flat wide steel box girder bridge section to the sunny side, L is the width of the north-south flat wide steel box girder bridge, Ν d It is the design service life of the north-south flat wide steel box girder bridge, in years. F HN1 (α) is the inverse function of the function, F HN2 (α) The inverse function, F HN1 (α) is the distribution function of the representative value of the negative temperature gradient at the positive side, F HN2 (α) is the distribution function of the representative value of the negative temperature gradient at the shadow side, μ HN1 , σ HN1 , μ HN2 , σ HN2 is an intermediate variable.

2. The transverse temperature gradient model of the north-south flat wide steel box girder bridge according to claim 1 is characterized by: In formula (1), the σ HP1 The value of is [0.23,0.38], μ HP1 The value of is [1.53,1.74], σ HP2 The value of is [0.26, 0.43], μ HP2 The value of is [1.53,1.77]. In formula (2), the μ HN1 The value of is [-0.67, 0.46], σ HN1 The value of is [0.24,0.39], μ HN2 The value of is [-0.95,-0.87], σ HN2 The value of is [0.08,0.14].

3. The transverse temperature gradient model of the north-south flat wide steel box girder bridge according to claim 1 is characterized in that In formula (1), N d , σ HP1 , μ HP1 , σ HP2 , μ HP2 The value of is: d is 100 years, σ HP1 is 0.3, μ HP1 is 1.63, σ HP2 is 0.34, μ HP2 is 1.

65.

4. The transverse temperature gradient model of the north-south flat wide steel box girder bridge according to claim 1 is characterized in that In formula (2), N d , σ HN1 , μ HN1 , σ HN2 , μ HN2 The value of is: d is 100 years, σ HN1 0.30, μ HN1 is -0.57, σ HN2 is 0.11, μ HN2 It is -0.91.

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