Long-life wide-width double-layer steel truss girder bridge temperature gradient fatigue load model

Abstract

A temperature gradient fatigue load model of a long-service-life wide-width double-layer steel truss girder bridge comprises an upper layer bridge floor, a lower layer bridge floor and a main truss temperature gradient fatigue load model, a vertical temperature gradient fatigue load model of the upper layer bridge floor is in a double-broken-line form, and a vertical temperature gradient fatigue load model of the lower layer bridge floor is in a three-broken-line form. The upper-layer bridge floor transverse temperature gradient fatigue load model is in a four-broken-line form, and the main truss temperature gradient fatigue load model is in a linear gradient form. The inventor analyzes the temperature load fatigue effect of the double-layer steel truss girder bridge by utilizing long-term monitoring data of a temperature field of the wide-width double-layer steel truss girder bridge, and establishes a transverse and vertical temperature gradient fatigue load model suitable for the long-life wide-width double-layer steel truss girder bridge with the design service life of 100 years, 150 years and 200 years by adopting a damage equivalence principle; the temperature gradient fatigue load model realizes temperature fatigue stress process calculation of the double-layer steel truss girder bridge, and can be used for anti-fatigue design and fatigue life evaluation of the double-layer steel truss girder bridge.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge engineering, and in particular relates to a temperature gradient fatigue load model of a long-life wide double-layer steel truss bridge. Background Art

[0002] Double-deck truss bridges are composed of main trusses, upper deck systems and lower deck systems, forming a complex time-varying spatial temperature field under the action of sunlight. Under the action of vertical nonlinear temperature gradient, longitudinal temperature fatigue stress will be generated inside each structural section of the double-deck steel truss bridge. Due to the overall frame effect of the system and the local frame effect of the structure of the double-deck truss, large transverse temperature fatigue stress will be generated under the action of the transverse temperature gradient, causing cumulative fatigue damage to the double-deck truss bridge. Therefore, it is necessary to carry out long-term temperature field monitoring based on the temperature field distribution characteristics of wide double-deck steel trusses, analyze the temperature load fatigue effect of double-deck truss bridges using temperature monitoring data, establish the vertical and transverse temperature gradient fatigue load model of wide double-deck steel truss bridges using the damage equivalence principle, calculate the temperature fatigue stress history of double-deck steel truss bridges, and conduct fatigue design and fatigue life assessment of double-deck steel truss bridges. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a temperature fatigue load model for a long-life wide double-layer truss.

[0004] The temperature gradient fatigue load model of the long-life wide double-deck steel truss bridge used to solve the above technical problems is composed of the vertical temperature gradient fatigue load model T of the upper bridge deck. GT (y), vertical temperature fatigue load model of lower deck T GB (y), upper deck transverse temperature fatigue load model T HD (x) The main truss temperature gradient fatigue load model is composed of.

[0005] The upper deck vertical temperature gradient fatigue load model T GT (y) is:

[0006]

[0007] In formula (1), y is the vertical distance from the typical position to the top of the upper bridge deck, T GT1 is the representative value of the temperature at the top of the upper bridge deck, in °C, T GT2 The vertical distance from the upper bridge deck is 0.2H T The temperature representative value is in °C, T GT3 is the representative value of the temperature at the bottom plate of the upper bridge deck, in °C, β GT (H T ), β GT(b1), p1, p2, and p3 are intermediate variables, b1 is the width of the lower wing plate of the upper bridge deck, H T is the upper bridge deck height, in m, is the initial temperature value at the top plate of the upper bridge deck, in °C. The vertical distance from the upper bridge deck is 0.2H T The initial temperature value, in °C, is the initial temperature of the upper deck bottom plate, in °C, N d It is the design service life, with the value of 100, 150 or 200, in years.

[0008] The vertical temperature gradient fatigue load model of the lower deck is T GB (y) is:

[0009]

[0010] In formula (2), y is the vertical distance from the top of the lower bridge deck, T GB1 is the representative value of the temperature at the top of the lower bridge deck, in °C, T GB2 The distance from the top of the lower bridge deck is 0.375H B The temperature representative value is in °C, T GB3 The vertical distance from the top of the lower bridge deck is 0.625H B The temperature representative value is in °C, T GB4 is the representative value of the temperature of the lower wing plate of the lower deck, in °C, H B represents the height of the lower bridge deck, b2 represents the width of the lower bridge deck, H B , b2 is in m, β GB (H B ), β GB (b2) is the intermediate variable, is the initial temperature of the top of the lower bridge deck, in °C, The distance from the top of the lower bridge deck is 0.375H B The initial temperature value is in °C. The vertical distance from the top of the lower bridge deck is 0.625H B The initial temperature value is in °C. is the initial temperature of the lower wing plate of the lower bridge deck, in ℃.

[0011] The upper deck transverse temperature gradient fatigue load model T HD (x) is:

[0012]

[0013] In formula (3), x is the horizontal distance from the edge of the upper deck top sun surface, W is the total width of the upper deck, W1 is the width of the upper chord, W2 is the width of the upper deck, and T HD1 is the representative value of the temperature at the sunny side of the upper bridge deck, in °C, T HD2 is the temperature representative value at the horizontal distance W2 from the upper bridge deck on the sunny side, in °C, T HD3 is the temperature representative value at the horizontal distance W2+0.5W1 from the sunny side of the upper bridge deck, in °C, T HD4 The temperature representative value at the horizontal distance W2+0.85W1 from the sunny side of the upper bridge deck, in °C, T HD5 is the representative value of the temperature on the shaded side of the upper bridge deck, in °C, W is the width of the upper steel bridge deck, in m, β HD (W) is the intermediate variable, is the initial temperature of the upper steel bridge deck on the positive side, in °C. is the initial temperature value at the horizontal distance W2 from the sun side of the upper bridge deck, in °C, The initial temperature value at the horizontal distance W2+0.5W1 from the sunny side of the upper bridge deck, in °C, The initial temperature value at the horizontal distance W2+0.85W1 from the sunny side of the upper bridge deck, in °C, It is the initial temperature value at the shady side of the upper bridge deck, in °C.

[0014] The main truss temperature gradient fatigue load model includes the vertical temperature gradient fatigue load model T of the main truss upper chord TC (y), vertical temperature gradient fatigue load model of the lower chord of the main truss T BC (y) and the web temperature gradient fatigue load model T FC (y).

[0015] The vertical temperature gradient fatigue load model T of the main truss upper chord TC (y) is:

[0016]

[0017] In formula (4), y is the vertical distance from the top plate of the main truss upper chord, T TC1 The representative value of the temperature at the top plate of the main truss upper chord, in °C, T TC2 The temperature representative value of the bottom plate of the upper chord of the main truss, in ℃, H C represents the cross-sectional height of the upper chord of the main truss, b3 represents the bottom plate width of the upper chord of the main truss, in m, β TC (W1), β TC (b3), p, q are intermediate variables, is the initial temperature of the top plate of the main truss upper chord, in °C. The initial temperature of the bottom plate of the upper chord of the main truss, in °C.

[0018] The vertical temperature gradient fatigue load model T of the lower chord of the main truss is BC (y) is:

[0019]

[0020] In formula (5), y is the vertical distance from the top of the lower chord of the main truss, T BC1 The representative value of the temperature at the top plate of the lower chord of the main truss, in °C, T BC2 The temperature representative value of the bottom plate of the main truss lower chord, in ℃, H BC The height of the lower chord of the main truss, W3 is the width of the top plate of the lower chord of the main truss, b4 is the width of the bottom plate of the lower chord, all in m, β BC (W3), β BC (b4) is the intermediate variable, is the initial temperature value at the top plate of the lower chord, in °C, is the initial temperature at the bottom plate of the lower chord, in °C.

[0021] The main truss web member temperature gradient fatigue load model T FC (y) is:

[0022]

[0023] In formula (6), x is the vertical distance from the outer wing plate of the web, T FC1 is the representative value of the temperature at the wing plate outside the web, in °C, T FC2 is the representative value of the temperature at the wing plate inside the web, in °C, B FC is the cross-sectional width of the web member, W4 is the width of the outer flange of the web member, b5 is the width of the inner flange of the web member, in m, β FC (W4), β FC (b5) is the intermediate variable, is the initial temperature of the wing plate outside the web, in °C. is the initial temperature of the wing plate inside the web, in °C.

[0024] More preferably, the The value range is [14.5,18.9], the unit is ℃, The value range is [5.9,8.3], the unit is ℃, H T The value range of is [1.0, 2.0], the unit is m, the value range of b1 is [0.3, 0.6], the unit is m; The value range is [13.4,14.8], the unit is ℃, H BThe value range of is [1.0, 2.0], the unit is m, the value range of b2 is [0.3, 0.6], the unit is m; in formula (3), the The value range is [14.4,15.4], the unit is ℃, The value range of is [11.5, 12.5], the unit is ℃, the value range of W is [12.0, 40.0], the unit is m; in formula (4), the The value range of is [10.9, 12.0], the unit is ℃, the value range of W1 is [0.8, 1.8], the unit is m, the value range of b3 is [0.8, 1.8], the unit is m; in formula (5), the The value range of is [10.0, 12.0], the unit is ℃, the value range of W3 is [0.8, 1.8], the unit is m, the value of b4 is [0.8, 1.8], the unit is m; in formula (6), the The value range is [2.0,3.0], the unit is ℃, the value range of W4 is [0.5,1.0], the unit is m, and the value range of b5 is [0.5,1.0], the unit is m.

[0025] More preferably, H in formula (1) T 、b1、 The value of is: H T is 1.6m, b1 is 0.6m, is 16.7℃, It is 7.1℃.

[0026] More preferably, H in formula (2) B 、b2、 The value of is: H B is 1.6m, b2 is 0.6m, It is 14.1℃.

[0027] More preferably, W and T in formula (3) HD1 , T HD2 The values ​​are: W is 31.7m, T HD1 14.9℃, T HD2 It is 12.0℃.

[0028] More preferably, W1, b3, The values ​​are: W1 is 1.2m, b3 is 1.2m, It is 11.0℃.

[0029] More preferably, W3, b4, The values ​​are: W3 is 1.2m, b4 is 1.2m, It is 11.0℃.

[0030] More preferably, W4, b5, The values ​​are: W4 is 0.7m, b5 is 0.7m, It is 2.6℃.

[0031] The beneficial effects of the present invention are as follows:

[0032] 1. The present invention utilizes the long-term monitoring data of the temperature field of a wide double-deck steel truss bridge to construct a long-life temperature gradient fatigue load model suitable for a design service life of 100, 150, and 200 years, taking full account of the influence of the upper and lower deck heights, the upper deck width, the chord top and bottom plate width, and the web wing plate width.

[0033] 2. The thermal fatigue load model of the long-life double-deck truss bridge constructed by the present invention is simple in form and realizes the calculation of the thermal fatigue stress history of double-deck truss bridges with a design service life of 100, 150 and 200 years, and can be used for the fatigue resistance design and fatigue life assessment of double-deck steel truss bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is the distribution of representative temperature values ​​in the vertical temperature fatigue load model of the upper deck of a wide double-deck steel truss girder.

[0035] Figure 2 It is the distribution of representative temperature values ​​in the vertical temperature fatigue load model of the lower deck of a wide double-deck steel truss girder.

[0036] Figure 3 The distribution of representative temperature values ​​in the transverse temperature fatigue load model of the upper deck of a wide double-layer steel truss girder.

[0037] Figure 4 This is the distribution of representative temperature values ​​in the temperature fatigue load model of the main truss of a wide double-layer steel truss girder.

[0038] Figure 5 This is a schematic diagram of the three-dimensional structure of a wide double-deck steel truss bridge.

[0039] Figure 6 Arrangement of actual temperature measurement points for wide double-layer steel trusses.

[0040] Figure 7 Temperature history of a wide double-deck steel truss bridge.

[0041] Figure 8 It is the histogram of stress amplitude of measured temperature field. DETAILED DESCRIPTION

[0042] 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.

[0043] Example 1

[0044] The temperature fatigue load model of the long-life wide double-deck steel truss bridge involved in this embodiment is composed of the vertical temperature gradient fatigue load model T of the upper bridge deck. GT (y), vertical temperature fatigue load model of lower deck T GB (y), upper deck transverse temperature fatigue load model T HD (x) The main truss temperature gradient fatigue load model is composed of the left side of the beam section as the sunny side and the right side of the beam section as the shady side. In actual use, it is judged based on the light intensity within a day, and the side with high light intensity is the sunny side;

[0045] The upper deck vertical temperature gradient fatigue load model T GT (y) is:

[0046]

[0047] In formula (1), y is the vertical distance from the typical position to the top of the upper bridge deck, T GT1 is the representative value of the temperature at the top of the upper bridge deck, in °C, T GT2 The vertical distance from the upper bridge deck is 0.2H T The temperature representative value is in °C, T GT3 is the representative value of the temperature at the bottom plate of the upper bridge deck, in °C, β GT (H T ), β GT (b1), p1, p2, and p3 are intermediate variables, b1 is the width of the lower wing plate of the upper bridge deck, H T is the upper bridge deck height, in m, is the initial temperature value at the top plate of the upper bridge deck, in °C. The vertical distance from the upper bridge deck is 0.2H T The initial temperature value, in °C, is the initial temperature of the upper deck bottom plate, in °C, N d It is the design service life, with the value of 100, 150 or 200, in years.

[0048] The vertical temperature gradient fatigue load model of the lower deck is T GB (y) is:

[0049]

[0050] In formula (2), y is the vertical distance from the top of the lower bridge deck, T GB1 is the representative value of the temperature at the top of the lower bridge deck, in °C, T GB2The distance from the top of the lower bridge deck is 0.375H B The temperature representative value is in °C, T GB3 The vertical distance from the top of the lower bridge deck is 0.625H B The temperature representative value is in °C, T GB4 is the representative value of the temperature of the lower wing plate of the lower deck, in °C, H B represents the height of the lower bridge deck, b2 represents the width of the lower bridge deck, H B , b2 is in m, β GB (H B ), β GB (b2) is the intermediate variable, is the initial temperature of the top of the lower bridge deck, in °C, The distance from the top of the lower bridge deck is 0.375H B The initial temperature value is in °C. The vertical distance from the top of the lower bridge deck is 0.625H B The initial temperature value is in °C. is the initial temperature of the lower wing plate of the lower bridge deck, in ℃.

[0051] The upper deck transverse temperature gradient fatigue load model T HD (x) is:

[0052]

[0053] In formula (3), x is the horizontal distance from the edge of the upper deck top sun surface, W is the total width of the upper deck, W1 is the width of the upper chord, W2 is the width of the upper deck, and T HD1 is the representative value of the temperature at the sunny side of the upper bridge deck, in °C, T HD2 is the temperature representative value at the horizontal distance W2 from the upper bridge deck on the sunny side, in °C, T HD3 is the temperature representative value at the horizontal distance W2+0.5W1 from the sunny side of the upper bridge deck, in °C, T HD4 The temperature representative value at the horizontal distance W2+0.85W1 from the sunny side of the upper bridge deck, in °C, T HD5 is the representative value of the temperature on the shaded side of the upper bridge deck, in °C, W is the width of the upper steel bridge deck, in m, β HD (W) is the intermediate variable, is the initial temperature of the upper steel bridge deck on the positive side, in °C. is the initial temperature value at the horizontal distance W2 from the sun side of the upper bridge deck, in °C, The initial temperature value at the horizontal distance W2+0.5W1 from the sunny side of the upper bridge deck, in °C, The initial temperature value at the horizontal distance W2+0.85W1 from the sunny side of the upper bridge deck, in °C, It is the initial temperature value at the shady side of the upper bridge deck, in °C.

[0054] The main truss temperature gradient fatigue load model includes the vertical temperature gradient fatigue load model T of the main truss upper chord TC (y), vertical temperature gradient fatigue load model of the lower chord of the main truss T BC (y) and the web temperature gradient fatigue load model T FC (y).

[0055] The vertical temperature gradient fatigue load model T of the main truss upper chord TC (y) is:

[0056]

[0057] In formula (4), y is the vertical distance from the top plate of the main truss upper chord, T TC1 The representative value of the temperature at the top plate of the main truss upper chord, in °C, T TC2 The temperature representative value of the bottom plate of the upper chord of the main truss, in ℃, H C represents the cross-sectional height of the upper chord of the main truss, b3 represents the bottom plate width of the upper chord of the main truss, in m, β TC (W1), β TC (b3), p, q are intermediate variables, is the initial temperature of the top plate of the main truss upper chord, in °C. The initial temperature of the bottom plate of the upper chord of the main truss, in °C.

[0058] The vertical temperature gradient fatigue load model T of the lower chord of the main truss is BC (y) is:

[0059]

[0060] In formula (5), y is the vertical distance from the top of the lower chord of the main truss, T BC1 The representative value of the temperature at the top plate of the lower chord of the main truss, in °C, T BC2 The temperature representative value of the bottom plate of the main truss lower chord, in ℃, H BC The height of the lower chord of the main truss, W3 is the width of the top plate of the lower chord of the main truss, b4 is the width of the bottom plate of the lower chord, all in m, β BC (W3), β BC (b4) is the intermediate variable, is the initial temperature value at the top plate of the lower chord, in °C, is the initial temperature at the bottom plate of the lower chord, in °C.

[0061] The main truss web member temperature gradient fatigue load model T FC (y) is:

[0062]

[0063] In formula (6), x is the vertical distance from the outer wing plate of the web, T FC1 is the representative value of the temperature at the wing plate outside the web, in °C, T FC2 is the representative value of the temperature at the wing plate inside the web, in °C, B FC is the cross-sectional width of the web member, W4 is the width of the outer flange of the web member, b5 is the width of the inner flange of the web member, in m, β FC (W4), β FC (b5) is the intermediate variable, is the initial temperature of the wing plate outside the web, in °C. is the initial temperature of the wing plate inside the web, in °C.

[0064] In the present embodiment, formula (1), the upper deck height H is selected T The width of the upper deck lower wing plate b1 is 1.6m, and the wide double-deck steel truss bridge is 0.6m. is 16.7℃, The corresponding upper deck vertical temperature fatigue load model T is constructed. GT (y). The temperature representative values ​​of the upper deck vertical temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 1. The temperature representative value distribution of the upper deck vertical temperature fatigue load model constructed according to this parameter is shown in Figure 1 shown.

[0065] Table 1 Representative values ​​of temperature of the vertical temperature fatigue load model of the upper deck

[0066]

[0067] In formula (2), the lower deck height H is selected B The width of the lower wing plate b2 of the lower deck is 0.6m, and the width of the double-deck steel truss bridge is 1.6m. The corresponding vertical temperature fatigue load model T of the lower deck is constructed. GB (y). The temperature representative values ​​of the vertical temperature fatigue load model of the lower deck corresponding to 100 years, 150 years, and 200 years are shown in Table 2. The temperature representative value distribution of the vertical temperature gradient fatigue load model of the lower deck constructed according to this parameter Figure 2 shown.

[0068] Table 2 Representative values ​​of temperature for the vertical temperature gradient fatigue gradient load model of the lower deck

[0069]

[0070] In formula (3), a wide double-deck steel truss bridge with an upper steel bridge deck truss width W of 31.7 m is selected. is 14.9℃, The corresponding upper deck transverse temperature gradient fatigue load model T is constructed. HD (x). The representative values ​​of the temperature of the upper steel bridge deck transverse temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 3. The fatigue temperature distribution at typical positions in the upper bridge deck transverse temperature fatigue load model constructed according to this parameter is shown in Figure 3 shown.

[0071] Table 3 Representative values ​​of temperature for the upper steel bridge deck transverse temperature gradient fatigue load model

[0072]

[0073] In formula (4), a wide double-deck steel truss bridge with a main truss upper chord top plate width W1 of 1.2 m and a main truss upper chord bottom plate width b3 of 1.2 m is selected. The vertical temperature gradient fatigue load model T of the upper chord of the main truss is constructed. TC (y). The temperature representative values ​​of the vertical temperature gradient fatigue load model of the upper chord corresponding to 100 years, 150 years, and 200 years are shown in Table 4. The temperature representative value distribution of the vertical temperature gradient fatigue load model of the upper chord of the main truss constructed according to the parameters is shown in Figure 4 shown.

[0074] Table 4 Representative values ​​of temperature of vertical temperature gradient fatigue load model of main truss upper chord

[0075]

[0076] In formula (5), a wide double-deck steel truss bridge with a main truss lower chord top plate width W3 of 1.2 m and a main truss lower chord bottom plate width b4 of 1.2 m is selected. The corresponding chord vertical temperature gradient fatigue load model T is constructed. BC (y). The temperature representative values ​​of the vertical temperature gradient fatigue load model of the chord corresponding to 100 years, 150 years, and 200 years are shown in Table 5. The temperature representative value distribution of the vertical temperature gradient fatigue load model of the lower chord constructed according to this parameter is shown in Figure 5 shown.

[0077] Table 5 Representative values ​​of temperature of vertical temperature gradient fatigue load model of main truss bottom chord

[0078]

[0079]

[0080] In formula (6), the width of the outer flange plate of the main truss web member W4 is 0.7m, and the width of the inner flange plate of the main truss web member b5 is 0.7m. The corresponding main truss web temperature gradient fatigue load model T is constructed. FC (y). The representative values ​​of the temperature of the web member temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 6. The fatigue temperature distribution at typical positions in the lower web member temperature gradient fatigue load model constructed according to this parameter is shown in Figure 6 shown.

[0081] Table 6 Representative values ​​of temperature for vertical temperature gradient fatigue load model of main truss web

[0082]

[0083] Example 2

[0084] The temperature gradient fatigue load model of the long-life wide double-deck steel truss bridge involved in this embodiment is the same as that of Embodiment 1, but the temperature representative value is different.

[0085] In the present embodiment, formula (1), the upper deck height H is selected T The width of the upper deck lower wing plate b1 is 1.0m and the wide double-deck steel truss bridge is 0.3m. 14.5℃, The corresponding upper deck vertical temperature fatigue load model T is constructed. GT (y). The temperature representative values ​​of the upper deck vertical temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 7. The temperature representative value distribution of the upper deck vertical temperature gradient fatigue load model constructed according to this parameter Figure 1 shown.

[0086] Table 7 Representative values ​​of temperature for the upper deck vertical temperature gradient fatigue load model

[0087]

[0088] In formula (2), the lower deck height H is selected B The width of the lower wing plate b2 of the lower deck is 0.3m, and the width of the lower wing plate b2 of the lower deck is 1.0m. The corresponding vertical temperature fatigue load model T of the lower deck is constructed. GB (y). The temperature representative values ​​of the vertical temperature gradient fatigue load model of the lower deck corresponding to 100 years, 150 years, and 200 years are shown in Table 8. The temperature representative value distribution of the vertical temperature gradient fatigue load model of the lower deck constructed according to this parameter Figure 1 shown.

[0089] Table 8 Representative values ​​of temperature for the vertical temperature gradient fatigue load model of the lower deck

[0090]

[0091] In formula (3), a wide double-deck steel truss bridge with an upper steel bridge deck truss width W of 12.0 m is selected. is 14.4℃, The corresponding upper deck transverse temperature gradient fatigue load model T is constructed. HD (x). The temperature representative values ​​of the upper steel bridge deck transverse temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 9. The distribution of the temperature representative values ​​of the upper steel bridge deck transverse temperature gradient fatigue load model constructed according to this parameter is shown in Figure 3 shown.

[0092] Table 9 Representative values ​​of temperature for the upper steel bridge deck transverse temperature gradient fatigue load model

[0093]

[0094] In formula (4), a wide double-deck steel truss bridge with a main truss upper chord top plate width W1 of 0.8 m and a main truss upper chord bottom plate width b3 of 0.8 m is selected. The vertical temperature gradient fatigue load model T of the upper chord of the main truss is constructed. TC (y). The temperature representative values ​​of the vertical temperature gradient fatigue load model of the upper chord corresponding to 100 years, 150 years, and 200 years are shown in Table 10. The temperature representative value distribution of the vertical temperature gradient fatigue load model of the upper chord of the main truss constructed according to the parameters is shown in Figure 4 shown.

[0095] Table 10 Representative values ​​of temperature of vertical temperature gradient fatigue load model of main truss upper chord

[0096]

[0097] In formula (5), a wide double-deck steel truss bridge with a main truss lower chord top plate width W3 of 0.8 m and a main truss lower chord bottom plate width b4 of 0.8 m is selected. The corresponding chord vertical temperature gradient fatigue load model T is constructed. BC (y). The temperature representative values ​​of the vertical temperature gradient fatigue load model of the chord corresponding to 100 years, 150 years, and 200 years are shown in Table 5. The temperature representative value distribution in the vertical temperature gradient fatigue load model of the lower chord constructed according to this parameter is shown in Figure 5 shown.

[0098] Table 11 Representative values ​​of vertical temperature gradient fatigue load model temperature of the lower chord of the main truss

[0099]

[0100] In formula (6), the width of the outer flange plate of the main truss web member W4 is 0.5m, and the width of the inner flange plate of the main truss web member b5 is 0.5m. The corresponding main truss web temperature gradient fatigue load model T is constructed. FC (y). The temperature representative values ​​of the web member temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 6. The temperature representative value distribution in the lower web member temperature gradient fatigue load model constructed according to this parameter is shown in Figure 6 shown.

[0101] Table 12 Representative values ​​of temperature for vertical temperature gradient fatigue load model of main truss web

[0102]

[0103] Example 3

[0104] The temperature gradient fatigue load model of the long-life wide double-deck steel truss bridge involved in this embodiment is the same as that of Embodiment 1, but the temperature representative value is different.

[0105] In the present embodiment, formula (1), the upper deck height H is selected T The width of the upper deck lower wing plate b1 is 2.0m and the wide double-deck steel truss bridge is 0.6m. is 18.9℃, The corresponding upper deck vertical temperature fatigue load model T is constructed. GT (y). The temperature representative values ​​of the upper deck vertical temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 13. The temperature representative value distribution of the upper deck vertical temperature gradient fatigue load model constructed according to this parameter Figure 1 shown.

[0106] Table 13 Representative values ​​of temperature for the vertical temperature gradient fatigue gradient load model of the upper deck

[0107]

[0108] In formula (2), the lower deck height H is selected B The width of the lower wing plate b2 of the lower deck is 2.0m, and the width of the lower wing plate b2 of the lower deck is 0.6m. The vertical temperature fatigue load model T of the lower deck is constructed. GB(y). The temperature representative values ​​of the vertical temperature gradient fatigue load model of the lower deck corresponding to 100 years, 150 years, and 200 years are shown in Table 14. The temperature representative value distribution of the vertical temperature gradient fatigue load model of the lower deck constructed according to this parameter Figure 1 shown.

[0109] Table 14 Representative values ​​of temperature for vertical temperature gradient fatigue gradient load model of lower deck

[0110]

[0111] In formula (3), a wide double-deck steel truss bridge with an upper steel bridge deck truss width W of 40.0 m is selected. 15.4℃, The corresponding upper deck transverse temperature gradient fatigue load model T is constructed. HD (x). The temperature representative values ​​of the upper steel bridge deck transverse temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 15. The temperature representative value distribution in the upper bridge deck transverse temperature gradient fatigue load model constructed according to this parameter is shown in Figure 3 shown.

[0112] Table 15 Representative values ​​of temperature for the upper steel bridge deck transverse temperature gradient fatigue load model

[0113]

[0114] In formula (4), a wide double-deck steel truss bridge with a main truss upper chord top plate width W1 of 1.8 m and a main truss upper chord bottom plate width b3 of 1.8 m is selected. The vertical temperature gradient fatigue load model T of the upper chord of the main truss is constructed. TC (y). The temperature representative values ​​of the vertical temperature gradient fatigue load model of the upper chord corresponding to 100 years, 150 years, and 200 years are shown in Table 16. The temperature representative value distribution of the vertical temperature gradient fatigue load model of the upper chord of the main truss constructed according to the parameters is shown in Figure 4 shown.

[0115] Table 16 Representative values ​​of temperature for vertical temperature gradient fatigue load model of main truss upper chord

[0116]

[0117] In formula (5), a wide double-deck steel truss bridge with a main truss lower chord top plate width W3 of 1.8 m and a main truss lower chord bottom plate width b4 of 1.8 m is selected. The corresponding chord vertical temperature gradient fatigue load model T is constructed. BC(y). The temperature representative values ​​of the vertical temperature gradient fatigue load model of the chord corresponding to 100 years, 150 years, and 200 years are shown in Table 17. The temperature representative value distribution in the vertical temperature gradient fatigue load model of the lower chord constructed according to this parameter is shown in Figure 4 shown.

[0118] Table 17 Representative values ​​of vertical temperature gradient fatigue load model temperature of the lower chord of the main truss

[0119]

[0120] In formula (6), the width W4 of the outer flange plate of the main truss web is 1.0 m, and the width b5 of the inner flange plate of the main truss web is 1.0 m. The corresponding main truss web temperature gradient fatigue load model T is constructed. FC (y). The temperature representative values ​​of the web member temperature gradient fatigue load model corresponding to 100 years, 150 years, and 200 years are shown in Table 18. The temperature representative value distribution in the lower web member temperature gradient fatigue load model constructed according to this parameter is shown in Figure 4 shown.

[0121] Table 18 Representative values ​​of temperature for vertical temperature gradient fatigue load model of main truss web

[0122]

[0123] Test 1

[0124] In order to verify the effect of the temperature fatigue load model of a long-life wide double-deck steel truss bridge, the inventors arranged vertical temperature sensors on the lower chord of the west main truss of the Weihe Bridge in Baqiao District, Xi'an City, Shaanxi Province, and conducted long-term temperature field monitoring. Figure 5 The specific construction process is as follows:

[0125] 1. Long-term monitoring instruments

[0126] The monitoring instrument is the JM3813 temperature acquisition instrument produced in Yangzhou, Jiangsu Province, the remote transmission system is JM1813, and the temperature measurement point uses a three-wire Pt100 sensor.

[0127] 2. Temperature measurement point arrangement

[0128] The temperature measuring points were arranged on the lower chord on the west side of the wide double-deck steel truss bridge. Two measuring points were arranged vertically. The measuring points were arranged as follows: Figure 6 As shown, they are arranged at the top and bottom of the inner side of the web of the west lower chord, and the collection interval is 5 minutes.

[0129] 3. Analysis of the effect of vertical temperature fatigue load model

[0130] 1. Taking the bottom plate of the lower chord on the west side of a wide double-deck steel truss bridge as an example, the temperature stress history curve is drawn based on the temperature measurement monitoring data, such as Figure 7 As shown in the figure, the temperature stress amplitude cycle counting method is used to obtain the stress amplitude histogram. The results are shown in Figure 8 Then, the equivalent fatigue stress was calculated based on the measured results, and the result was 10.6MPa.

[0131] The temperature stress history is constructed based on the temperature fatigue load model and the temperature stress amplitude analysis is performed. The width of the top plate of the lower chord is 1.2m, the width of the bottom plate of the lower chord is 1.2m, and N d Assuming 100 years, substitute the following formula to solve the equivalent temperature fatigue stress σ of the lower chord measured GC,eq (y):

[0132] σ GC,eq (y) = α × E × T GC (y)

[0133] Where α is the thermal expansion coefficient of steel, and E is the elastic modulus of steel.

[0134] The equivalent temperature fatigue stress of the lower chord is 10.9 MPa, which is basically consistent with the measured equivalent temperature fatigue stress of the lower chord. This shows that the vertical temperature fatigue load model of the lower chord on the west side of the wide double-deck steel truss bridge can be used for vertical temperature and temperature-vehicle coupling fatigue damage assessment of wide double-deck steel truss bridges, and has good applicability.

Claims

1. A temperature gradient fatigue load model for a long-life wide double-deck steel truss bridge, characterized by: The temperature gradient fatigue load model is composed of the upper deck vertical temperature gradient fatigue load model T GT (y), vertical temperature fatigue load model of lower deck T GB (y), upper deck transverse temperature fatigue load model T HD (x) Composition of the main truss temperature gradient fatigue load model; The upper deck vertical temperature gradient fatigue load model T GT (y) is: In formula (1), y is the vertical distance from the typical position to the top of the upper bridge deck, T GT1 is the representative value of the temperature at the top of the upper bridge deck, in °C, T GT2 The vertical distance from the upper bridge deck is 0.2H T The temperature representative value is in °C, T GT3 is the representative value of the temperature at the bottom plate of the upper bridge deck, in °C, β GT (H T ), β GT (b1), p1, p2, and p3 are intermediate variables, b1 is the width of the lower wing plate of the upper bridge deck, H T is the upper bridge deck height, in m, is the initial temperature value at the top plate of the upper bridge deck, in °C. The vertical distance from the upper bridge deck is 0.2H T The initial temperature value, in °C, is the initial temperature of the upper deck bottom plate, in °C, N d is the design service life, the value is 100, 150 or 200, in years; The vertical temperature gradient fatigue load model of the lower deck is T GB (y) is: In formula (2), y is the vertical distance from the top of the lower bridge deck, T GB1 is the representative value of the temperature at the top of the lower bridge deck, in °C, T GB2 The distance from the top of the lower bridge deck is 0.375H B The temperature representative value is in °C, T GB3 The vertical distance from the top of the lower bridge deck is 0.625H B The temperature representative value is in °C, T GB4 is the representative value of the temperature of the lower wing plate of the lower deck, in °C, H B represents the height of the lower bridge deck, b2 represents the width of the lower bridge deck, H B , b2 is in m, β GB (H B ), β GB (b2) is the intermediate variable, is the initial temperature of the top of the lower bridge deck, in °C, The distance from the top of the lower bridge deck is 0.375H B The initial temperature value is in °C. The vertical distance from the top of the lower bridge deck is 0.625H B The initial temperature value is in °C. is the initial temperature value of the lower wing plate of the lower bridge deck, in °C; The upper deck transverse temperature gradient fatigue load model T HD (x) is: In formula (3), x is the horizontal distance from the edge of the upper deck top sun surface, W is the total width of the upper deck, W1 is the width of the upper chord, W2 is the width of the upper deck, and T HD1 is the representative value of the temperature at the sunny side of the upper bridge deck, in °C, T HD2 is the temperature representative value at the horizontal distance W2 from the upper bridge deck on the sunny side, in °C, T HD3 is the temperature representative value at the horizontal distance W2+0.5W1 from the sunny side of the upper bridge deck, in °C, T HD4 The temperature representative value at the horizontal distance W2+0.85W1 from the sunny side of the upper bridge deck, in °C, T HD5 is the representative value of the temperature on the shaded side of the upper bridge deck, in °C, W is the width of the upper steel bridge deck, in m, β HD (W) is the intermediate variable, is the initial temperature of the upper steel bridge deck on the positive side, in °C. is the initial temperature value at the horizontal distance W2 from the sun side of the upper bridge deck, in °C, The initial temperature value at the horizontal distance W2+0.5W1 from the sunny side of the upper bridge deck, in °C, The initial temperature value at the horizontal distance W2+0.85W1 from the sunny side of the upper bridge deck, in °C, is the initial temperature value at the dark side of the upper bridge deck, in °C; The main truss temperature gradient fatigue load model includes the vertical temperature gradient fatigue load model T of the main truss upper chord TC (y), vertical temperature gradient fatigue load model of the lower chord of the main truss T BC (y) and the web temperature gradient fatigue load model T FC (y); The vertical temperature gradient fatigue load model T of the main truss upper chord TC (y) is: In formula (4), y is the vertical distance from the top plate of the main truss upper chord, T TC1 The representative value of the temperature at the top plate of the main truss upper chord, in °C, T TC2 The temperature representative value of the bottom plate of the upper chord of the main truss, in ℃, H C represents the cross-sectional height of the upper chord of the main truss, b3 represents the bottom plate width of the upper chord of the main truss, in m, β TC (W1), β TC (b3), p, q are intermediate variables, is the initial temperature of the top plate of the main truss upper chord, in °C. is the initial temperature value of the bottom plate of the upper chord of the main truss, in °C; The vertical temperature gradient fatigue load model T of the lower chord of the main truss is BC (y) is: In formula (5), y is the vertical distance from the top of the lower chord of the main truss, T BC1 The representative value of the temperature at the top plate of the lower chord of the main truss, in °C, T BC2 The temperature representative value of the bottom plate of the main truss lower chord, in ℃, H BC The height of the lower chord of the main truss, W3 is the width of the top plate of the lower chord of the main truss, b4 is the width of the bottom plate of the lower chord, all in m, β BC (W3), β BC (b4) is the intermediate variable, is the initial temperature value at the top plate of the lower chord, in °C, is the initial temperature value at the bottom plate of the lower chord, in °C; The main truss web member temperature gradient fatigue load model T FC (y) is: In formula (6), x is the vertical distance from the outer wing plate of the web, T FC1 is the representative value of the temperature at the wing plate outside the web, in °C, T FC2 is the representative value of the temperature at the wing plate inside the web, in °C, B FC is the cross-sectional width of the web member, W4 is the width of the outer flange of the web member, b5 is the width of the inner flange of the web member, in m, β FC (W4), β FC (b5) is the intermediate variable, is the initial temperature of the wing plate outside the web, in °C. is the initial temperature of the wing plate inside the web, in °C.

2. The temperature gradient fatigue load model of the long-life wide double-deck steel truss bridge according to claim 1 is characterized by: In formula (1) The value range is [14.5,18.9], the unit is ℃, The value range is [5.9,8.3], the unit is ℃, H T The value range of is [1.0, 2.0], the unit is m, the value range of b1 is [0.3, 0.6], the unit is m; The value range is [13.4,14.8], the unit is ℃, H B The value range of is [1.0, 2.0], the unit is m, the value range of b2 is [0.3, 0.6], the unit is m; In formula (3), The value range is [14.4,15.4], the unit is ℃, The value range of is [11.5, 12.5], the unit is ℃, the value range of W is [12.0, 40.0], the unit is m; in formula (4), the The value range of is [10.9, 12.0], the unit is ℃, the value range of W1 is [0.8, 1.8], the unit is m, the value range of b3 is [0.8, 1.8], the unit is m; in formula (5), the The value range of is [10.0, 12.0], the unit is ℃, the value range of W3 is [0.8, 1.8], the unit is m, the value of b4 is [0.8, 1.8], the unit is m; In formula (6), The value range is [2.0,3.0], the unit is ℃, the value range of W4 is [0.5,1.0], the unit is m, and the value range of b5 is [0.5,1.0], the unit is m.

3. The temperature gradient fatigue load model for a long-life wide double-deck steel truss bridge according to claim 1 is characterized in that H described in formula (1) T 、b1、 The value of is: H T is 1.6m, b1 is 0.6m, is 16.7℃, It is 7.1℃.

4. The temperature gradient fatigue load model for a long-life wide double-deck steel truss bridge according to claim 1 is characterized in that H described in formula (2) B 、b2、 The value of is: H B is 1.6m, b2 is 0.6m, It is 14.1℃.

5. The temperature gradient fatigue load model for a long-life wide double-deck steel truss bridge according to claim 1 is characterized in that W and T in formula (3) HD1 , T HD2 The values ​​are: W is 31.7m, T HD1 14.9℃, T HD2 It is 12.0℃.

6. The temperature gradient fatigue load model for a long-life wide double-deck steel truss bridge according to claim 1 is characterized in that W1, b3, The values ​​are: W1 is 1.2m, b3 is 1.2m, It is 11.0℃.

7. The temperature gradient fatigue load model for a long-life wide double-deck steel truss bridge according to claim 1 is characterized in that W3, b4, The values ​​are: W3 is 1.2m, b4 is 1.2m, It is 11.0℃.

8. The temperature gradient fatigue load model for a long-life wide double-deck steel truss bridge according to claim 1 is characterized in that W4, b5, The values ​​are: W4 is 0.7m, b5 is 0.7m, It is 2.6℃.

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