Asymmetric wing-plate-free steel box girder bridge transverse temperature gradient model

Abstract

A transverse temperature gradient model of an asymmetric wing-plate-free steel box girder bridge is composed of a transverse positive temperature gradient model and a transverse negative temperature gradient model which are both in a three-fold-line form. Temperature measuring points are arranged according to the section characteristics of the wing-plate-free steel box girder and the distribution characteristics of a temperature field, long-term monitoring of the transverse temperature field of the wing-plate-free steel box girder bridge is carried out, and statistical analysis and least square fitting are carried out on the transverse daily extreme temperature difference. A transverse temperature gradient model suitable for the 100-year, 150-year and 200-year design service life of the asymmetric wing-plate-free steel box girder bridge is constructed, the influence of the design service life and the section height is considered in the model, and the transverse temperature gradient model can be used for solving the transverse temperature stress of the asymmetric wing-plate-free steel box girder bridge.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge engineering, and in particular relates to a transverse temperature gradient model of an asymmetric flangeless steel box girder bridge. Background Art

[0002] The steel box girder section is a typical closed section. Under the action of solar radiation, a transverse temperature field will be generated inside the structure. Due to the frame effect of the closed section, the structure will produce a large transverse temperature additional stress. The asymmetric steel box girder section without flanges has a great influence on the area of ​​solar radiation and the flow field around the section. Its transverse temperature field distribution characteristics are quite different from those of steel box girder bridges with flanges. However, there is no temperature gradient model for asymmetric steel box girder bridges without flanges in the bridge design specifications. Therefore, it is necessary to arrange measurement points according to the transverse temperature field distribution characteristics of asymmetric steel box girder bridges without flanges, carry out long-term temperature field monitoring, and construct a transverse temperature gradient model for asymmetric steel box girder bridges without flanges with a design service life of 100 to 200 years to support the calculation and analysis of transverse temperature stress of steel box girder bridges without flanges. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a transverse temperature gradient model of an asymmetric steel box girder bridge without flanges, which can be used for calculating the transverse temperature gradient model of an asymmetric steel box girder bridge without flanges.

[0004] The above-mentioned transverse temperature gradient model of the asymmetric flangeless 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.

[0005] The transverse positive temperature gradient model T HP (x) is as shown in formula (1):

[0006]

[0007] 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 between the transverse position of the asymmetric flangeless steel box girder bridge section and the sunny side, L is the width of the asymmetric flangeless steel box girder bridge, Ν d The design service life of the asymmetric flangeless steel box girder bridge is in years, with a value of 100, 150 or 200. F P1 (α) is the inverse function of the function, F P2 (α) The inverse function, F P1 (α) is the distribution function of the representative value of the positive temperature gradient at the positive side, FP2 (α) is the distribution function of the representative value of the positive temperature gradient at the shadow side, α, α P1 , β P1 , α P2 , β P2 is an intermediate variable.

[0008] The lateral negative temperature gradient model T HN (x) is shown in formula (2):

[0009]

[0010] 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 negative temperature gradient at the shaded position, in °C, x is any transverse position of the asymmetric flangeless steel box girder bridge section, L is the width of the asymmetric flangeless steel box girder bridge, F N1 (α) is the inverse function of the function, F N2 (α) The inverse function, F N1 (α) is the distribution function of the representative value of the negative temperature gradient at the positive side, F N2 (α) is the distribution function of the representative value of the negative temperature gradient at the shadow side, α N1 , β N1 , α N2 , β N2 is an intermediate variable.

[0011] In the formula (1) of the present invention, the α P1 The value of is [14.34,18.85], β P1 The value of is [2.04,3.52], α P2 The value of is [9.60,12.00], β P2 The value of is [2.52,4.28]. In formula (2), the α N1 The value of is [5.66,6.26], β N1 The value of is [5.52,9.29], α N2 The value of is [6.36,6.95], β N2 The value is [6.42,10.63].

[0012] In the formula (1) of the present invention, the N d , α P1 , β P1 , α P2 , β P2 The value of is: d For 100 years, α P1The best is 16.44, the best β P1 is 2.68, α P2 The best is 10.74, β P2 The best is 3.28.

[0013] In formula (2) of the present invention, N d , α N1 , β N1 , α N2 , β N2 The value of is: d For 100 years, α N1 The best is 5.95, β N1 The best is 7.16, α N2 The best is 6.65, β N2 The best is 8.26.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. The present invention utilizes the long-term monitoring data of the transverse temperature field of the asymmetric flangeless steel box girder bridge to construct a transverse temperature gradient model of the asymmetric flangeless steel box girder bridge. The constructed transverse temperature gradient model takes into account the influence of the top plate width of the asymmetric flangeless steel box girder, the design service life and the temperature probability distribution characteristics.

[0016] 2. The transverse temperature gradient model of the asymmetric flangeless steel box girder bridge constructed by the present invention is simple in form and can be used for the long-life design of asymmetric flangeless steel box girder bridges with a design service life of 100, 150 and 200 years. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the cross-section of an asymmetric steel box girder bridge without flanges.

[0018] Figure 2 It is the temperature representative value distribution diagram of the transverse positive temperature model of an asymmetric flangeless steel box girder bridge.

[0019] Figure 3 It is the temperature representative value distribution diagram of the transverse negative temperature model of an asymmetric flangeless steel box girder bridge.

[0020] Figure 4 This is the arrangement diagram of transverse temperature measuring points for the measured temperature field of an asymmetric flangeless steel box girder bridge.

[0021] Figure 5 It is the temperature history curve at the measuring point of the asymmetric flangeless steel box girder bridge.

[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 HP2 Histogram 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] The transverse temperature gradient model of the asymmetric flangeless steel box girder bridge in this embodiment is composed of the transverse positive temperature gradient model T HP (x) and the lateral negative temperature gradient model T HN (x) structure, wherein, in this embodiment, the left side of the beam cross section is defined as the sunny side, and the right side of the beam cross section is defined as the shaded side. In actual use, it is determined based on the light intensity within a day, and the side with higher light intensity is the sunny 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 between the transverse position of the asymmetric flangeless steel box girder bridge section and the sunny side, L is the width of the asymmetric flangeless steel box girder bridge, Ν d The design service life of the asymmetric flangeless steel box girder bridge is in years, with a value of 100, 150 or 200. F P1 (α) is the inverse function of the function, F P2 (α) The inverse function, F P1 (α) is the distribution function of the representative value of the positive temperature gradient at the positive side, F P2 (α) is the distribution function of the representative value of the positive temperature gradient at the shadow side, α, α P1 , β P1 , α P2 , β P2 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 negative temperature gradient at the shaded position, in °C, x is any transverse position of the asymmetric flangeless steel box girder bridge section, L is the width of the asymmetric flangeless steel box girder bridge, F N1 (α) is the inverse function of the function, F N2 (α) The inverse function, F N1 (α) is the distribution function of the representative value of the negative temperature gradient at the positive side, F N2 (α) is the distribution function of the representative value of the negative temperature gradient at the shadow side, α N1 , β N1 , α N2 , β N2 is an intermediate variable.

[0035] In this embodiment, an asymmetric steel box girder bridge without flange in Guangdong is taken as an example. Its three-dimensional cross section is as follows: Figure 1 As shown in formula (1), α P1 is 16.44, β P1 is 2.68, α P2 is 10.74, β P2 =3.28, and the corresponding transverse temperature gradient model of the asymmetric steel box girder bridge without flange 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 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), α N1 is 5.95, β N1 is 7.16, α N2 is 6.65, β N2 =8.26, and the corresponding transverse temperature gradient model of the asymmetric steel box girder bridge without flange 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 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 asymmetric flangeless steel box girder bridge involved in this embodiment is the same as that in Embodiment 1, but the temperature representative value is different.

[0043] In this embodiment, an asymmetric steel box girder bridge without flange is taken as an example. In formula (1), α P1 is 14.34, β P1 is 2.04, α P2 is 9.60, β P2 =2.52, and the corresponding transverse temperature gradient model of the asymmetric flangeless 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 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), α N1 is 5.66, β N1 is 5.52, α N2 is 6.36, β N2 is 6.42, and the corresponding transverse temperature gradient model of the asymmetric flangeless 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 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 asymmetric flangeless steel box girder bridge involved in this embodiment is the same as that in Embodiment 1, but the temperature representative value is different.

[0051] In this embodiment, an asymmetric steel box girder bridge without flange is taken as an example. In formula (1), αP1 is 18.85, β P1 is 3.52, α P2 is 12.00, β P2 =4.28, and the corresponding transverse temperature gradient model of the asymmetric flangeless 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 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), α N1 is 6.26, β N1 is 9.29, α N2 is 6.95, β N2 =10.63. The corresponding transverse temperature gradient model of the asymmetric steel box girder bridge without flange 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 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 temperature gradient model of an asymmetric flangeless steel box girder bridge, the inventors arranged transverse temperature sensors on the Taiping Waterway Bridge in Humen Town, Dongguan City, Guangdong Province 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 temperature measuring points are arranged transversely on the top plate of the asymmetric steel box girder bridge without flanges. The coordinate system is established with the positive side edge of the top plate of the asymmetric steel box girder bridge without flanges as the coordinate origin. The arrangement principle of the temperature measuring points on the top plate of the asymmetric steel box girder bridge without flanges 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 0.000m, 5.375m, 10.375m, and 15.750m from the horizontal distance from the coordinate origin, and are recorded as LT1~LT4. 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 transverse positive temperature gradient model of an asymmetric steel box girder bridge without flange, T HP1 and T HP2 Taking the position as an example, the temperature history curve is drawn using the measured temperature field 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. Take the temperature difference corresponding to the 99% guarantee rate in the probability density function respectively, and get T HP1 and T HP2 The representative values ​​of temperature gradients at these locations are 20.9°C and 14.2°C, respectively.

[0065] The temperature gradient model corresponding to the design service life of 100 years is constructed by using the transverse temperature gradient model of the asymmetric flangeless steel box girder bridge. P1 is 16.44, β P1 is 2.68, α P2 is 10.74, β P2 is 3.28, and T HP1 and T HP2 The results are 21.9℃ and 14.4℃, 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 temperature gradient model of an asymmetric flangeless steel box girder bridge, the inventors arranged transverse temperature sensors on the Taiping Waterway Bridge in Humen Town, Dongguan City, Guangdong Province 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 an asymmetric steel box girder bridge without flange is used as the HN1 and T HN1 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 HN1 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 1% guarantee rate 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 -14.1°C and -9.2°C respectively.

[0074] The transverse temperature gradient model of an asymmetric flangeless steel box girder bridge is used to construct a temperature gradient model corresponding to a design service life of 100 years. N1 is 5.95, β N1 is 7.16, α N2 is 6.65, β N2 is 8.26, and T HN1 and T HN2 The results show that the lateral negative temperature gradient model has good applicability.

Claims

1. A transverse temperature gradient model for an asymmetric flangeless steel box girder bridge, characterized in that: The temperature gradient model is composed of the 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) is as shown in formula (1): 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 between the transverse position of the asymmetric flangeless steel box girder bridge section and the sunny side, L is the width of the asymmetric flangeless steel box girder bridge, Ν d The design service life of the asymmetric flangeless steel box girder bridge is in years, with a value of 100, 150 or 200. F P1 (α) is the inverse function of the function, F P2 (α) The inverse function, F P1 (α) is the distribution function of the representative value of the positive temperature gradient at the positive side, F P2 (α) is the distribution function of the representative value of the positive temperature gradient at the shadow side, α, α P1 , β P1 , α P2 , β P2 is an intermediate variable; The lateral negative temperature gradient model T HN (x) is shown in formula (2): 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 negative temperature gradient at the shaded position, in °C, x is any transverse position of the asymmetric flangeless steel box girder bridge section, L is the width of the asymmetric flangeless steel box girder bridge, F N1 (α) is the inverse function of the function, F N2 (α) The inverse function, F N1 (α) is the distribution function of the representative value of the negative temperature gradient at the positive side, F N2 (α) is the distribution function of the representative value of the negative temperature gradient at the shadow side, α N1 , β N1 , α N2 , β N2 is an intermediate variable.

2. According to the transverse temperature gradient model of the asymmetric flangeless steel box girder bridge of claim 1, it is characterized by: In formula (1), the α P1 The value of is [14.34,18.85], β P1 The value of is [2.04,3.52], α P2 The value of is [9.60,12.00], β P2 The value of is [2.52,4.28]. In formula (2), the α N1 The value of is [5.66,6.26], β N1 The value of is [5.52,9.29], α N2 The value of is [6.36,6.95], β N2 The value is [6.42,10.63].

3. The transverse temperature gradient model of the asymmetric flangeless steel box girder bridge according to claim 1 is characterized by: In formula (1), N d , α P1 , β P1 , α P2 , β P2 The value of is: d For 100 years, α P1 is 16.44, β P1 is 2.68, α P2 is 10.74, β P2 It is 3.

28.

4. The transverse temperature gradient model of the asymmetric flangeless steel box girder bridge according to claim 1 is characterized by: In formula (2), N d , α N1 , β N1 , α N2 , β N2 The value of is: d For 100 years, α N1 is 5.95, β N1 is 7.16, α N2 is 6.65, β N2 It is 8.26.

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