Double-layer steel truss girder drainage system and design method

Abstract

The invention relates to a double-layer steel truss girder drainage system and a design method, and relates to the technical field of bridge design, the double-layer steel truss girder drainage system comprises an upper-layer drainage pipeline, the upper-layer drainage pipeline comprises an upper-layer collection water pipe and an upper-layer drainage drainage pipe with the set drainage amount, and a water inlet of the upper-layer collection water pipe is located in the lower side of a truss girder upper chord member in the transverse bridge direction; the upper-layer water collecting pipe is communicated with an upper-layer drainage drain pipe; the upper-layer drainage drain pipe is positioned on the outer side of the lower side of the truss lower chord in the transverse bridge direction; a water inlet of the lower-layer drainage pipeline is positioned on the lower chord of the trussed girder, and a drainage port is positioned on the lower side of the lower chord of the trussed girder. The problems that in practical engineering application in the prior art, especially in coastal areas, mountainous areas and other areas where strong wind frequently happens, when strong wind acts on the bridge, rainwater discharged by an overflow pipe of an upper-layer bridge floor can be blown to the inner side of the bridge by the wind and directly falls to a lower-layer bridge floor, the burden of lower-layer drainage is intensified, the drainage speed is affected, and driving safety is possibly affected are solved.

Description

Technical Field

[0001] This invention relates to the field of bridge design technology, specifically to a double-layer steel truss drainage system and its design method. Background Technology

[0002] With the increasing complexity of urban transportation networks and the growing scarcity of land resources, double-deck steel truss bridges, as a form of bridge that efficiently utilizes space, have been widely used in modern urban transportation construction. These bridges typically have a motor vehicle lane on the upper level and a non-motorized vehicle lane or pedestrian walkway on the lower level, effectively improving road capacity. However, the special structure of double-deck bridges also presents unique drainage challenges. Drainage of double-deck steel truss bridges has always been a crucial factor affecting bridge operation, especially for curved steel truss bridges. To meet the centrifugal force requirements of traffic, the bridge deck must have a large unidirectional cross slope, with the catchment area and drainage intensity of a unidirectional cross slope bridge deck being twice that of a traditional bidirectional cross slope.

[0003] In existing technologies, the drainage structure of traditional double-layer truss bridges often involves installing a continuous longitudinal drainage pipe on the upper layer. When the designed water volume is large, an overflow pipe is added to directly discharge the rainwater that cannot be drained in time to the outside of the bridge. Due to the obstruction of the upper bridge deck, the longitudinal water pipes on the lower deck are generally designed to be smaller than those on the upper deck.

[0004] However, in practical engineering applications, especially in areas with frequent strong winds such as coastal and mountainous regions, when strong winds act on bridges, rainwater discharged from the overflow pipes on the upper deck is blown to the inside of the bridge and falls directly onto the lower deck, increasing the burden on the lower drainage system, affecting drainage speed, and potentially affecting driving safety. Summary of the Invention

[0005] This application provides a double-layer steel truss drainage system and design method, which can solve the problem in the existing technology in practical engineering applications, especially in coastal and mountainous areas where strong winds are frequent. When strong winds act on the bridge, the rainwater discharged from the overflow pipe of the upper bridge deck is blown to the inside of the bridge and falls directly to the lower bridge deck, which increases the burden on the lower drainage layer, affects the drainage speed, and may affect driving safety.

[0006] In a first aspect, embodiments of this application provide a double-layer steel truss drainage system, comprising: The upper drainage pipeline includes an upper water collection pipe and an upper drainage pipe with a set drainage capacity. The inlet of the upper water collection pipe is located on the lower side of the upper chord of the truss in the transverse direction. The upper water collection pipe is connected to the upper drainage pipe. The upper drainage pipe is located on the outer side of the lower chord of the truss in the transverse direction. The lower drainage pipe has its inlet located on the lower chord of the truss and its outlet located below the lower chord of the truss.

[0007] In one embodiment, the upper water collection pipe includes: The upper longitudinal water collection pipe has its inlet located on the lower side of the upper chord of the truss in the transverse direction; Multiple drainage pipes with a web-like structure are provided, with the upper end of each drainage pipe connected to the upper longitudinal water collection pipe and the lower end connected to the upper drainage pipe.

[0008] In one embodiment, the upper longitudinal water collection pipe includes longitudinal water collection pipe units in the same number as the web bar drainage pipes. The longitudinal water collection pipe units are spaced apart along the longitudinal bridge direction, and one end of each longitudinal water collection pipe unit is connected to the upper end of the corresponding web bar drainage pipe.

[0009] In one embodiment, the upper water collection pipe further includes multiple vertical guide pipes, with the inlet of one end of each vertical guide pipe located on the lower side of the transverse direction of the upper chord of the truss, and the other end connected to the upper longitudinal water collection pipe.

[0010] In one embodiment, the upper drainage pipe includes: A longitudinal drainage pipe is provided along the lower chord of the truss and is located on the outer side of the lower chord in the transverse direction. The drain outlet of the longitudinal drainage pipe is located on the lower side of the lower chord in the longitudinal direction. Multiple overflow pipes are connected to the longitudinal drainage pipe and are spaced apart along the length of the longitudinal drainage pipe.

[0011] In one embodiment, the lower drainage pipe includes drainage units corresponding to the number of areas between the diagonal web members of the truss, the drainage unit comprising: The lower longitudinal drainage pipe is located below the lower transverse side of the area between the diagonal web members of the truss; Multiple lower vertical guide pipes have their inlets located on the lower side of the lower chord of the truss in the transverse direction, and their other ends connected to the lower longitudinal drainage pipes.

[0012] Secondly, this application also provides a design method for a double-layer steel truss drainage system, which is used to design the above-mentioned double-layer steel truss drainage system, including the following steps: Based on the climate parameters of the bridge site area, rainfall thresholds were obtained; Based on the catchment area and rainfall threshold of the upper bridge deck, the design runoff of the upper bridge deck is obtained; The drainage volume of the upper-level drainage pipe is determined based on the designed flow rate of the upper-level bridge deck.

[0013] In one embodiment, before obtaining the design runoff volume of the upper bridge deck based on the catchment area and rainfall threshold of the upper bridge deck, the method further includes: The catchment area of ​​the upper bridge deck is obtained based on the total length of all longitudinal water collection pipe units and the width of the upper bridge deck.

[0014] In one embodiment, the method further includes the step of setting the diameter of the lower vertical guide pipe, comprising: Based on the climate parameters of the bridge site area, the rainwater deflection angle was obtained; The design runoff of the lower bridge deck is obtained based on the rainwater deflection angle, the width of the upper bridge deck shielding, the bridge truss height, the width of the lower bridge deck, the full span length of the lower bridge deck, and the rainfall threshold. The diameter of the vertical guide pipe for the lower level is determined based on the design flow rate of the lower bridge deck.

[0015] In one implementation, obtaining the design runoff capacity of the lower bridge deck based on the rainwater deflection angle, the width of the upper bridge deck's obstruction, the bridge truss height, the width of the lower bridge deck, the total span length of the lower bridge deck, and a rainfall threshold includes: The water catchment width of the lower bridge deck is obtained based on the rainwater deflection angle, the width of the upper bridge deck's shielding, the bridge truss height, and the width of the lower bridge deck. The design runoff of the lower bridge deck is obtained based on the catchment width, total span length, width, and rainfall threshold of the lower bridge deck.

[0016] The beneficial effects of the technical solutions provided in this application include: In designing this double-layer steel truss drainage system, the upper-layer drainage pipeline includes an upper-layer collection pipe and an upper-layer diversion drainage pipe with a set drainage capacity. The inlet of the upper-layer collection pipe is located on the lower side of the upper chord of the truss in the transverse direction. The upper-layer collection pipe is connected to the upper-layer diversion drainage pipe, which is located on the outer side of the lower chord of the truss in the transverse direction. The inlet of the lower-layer drainage pipeline is located on the lower chord of the truss, and the outlet is located below the lower chord of the truss. When designing the drainage capacity of the upper-layer diversion drainage pipe, the rainfall threshold is first obtained based on the climate parameters of the bridge site area; then, the design runoff of the upper bridge deck is obtained based on the catchment area and rainfall threshold of the upper bridge deck; finally, the drainage capacity of the upper-layer diversion drainage pipe is set according to the design runoff of the upper bridge deck. By placing the upper-level drainage pipes on the outer side of the lower chord of the truss, rainwater from the upper bridge deck is directly discharged to the outer side of the bridge, preventing the phenomenon in traditional designs where overflowing rainwater from the upper deck is blown onto the lower bridge deck by strong winds. Furthermore, the upper-level drainage pipes direct rainwater to the outer side of the lower chord of the truss, while the lower-level drainage pipes independently handle rainwater from the lower bridge deck, ensuring complete spatial separation and avoiding the interference between the upper and lower drainage systems in traditional designs. This solves the problem in practical engineering applications, especially in coastal and mountainous areas prone to strong winds, where rainwater discharged from the upper bridge deck overflow pipes is blown inwards by strong winds and falls directly onto the lower bridge deck, increasing the burden on the lower drainage system, affecting drainage speed, and potentially impacting traffic safety. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural schematic diagram of an embodiment of a double-layer steel truss drainage system according to the present invention.

[0019] Figure 2 This is a schematic cross-sectional view of an embodiment of a double-layer steel truss drainage system according to the present invention.

[0020] Figure 3 This is a schematic diagram illustrating drainage calculations under the condition of upper bridge deck obstruction in an embodiment of a double-layer steel truss drainage system of the present invention.

[0021] Figure 4 This is a schematic diagram of the overflow pipe in an embodiment of a double-layer steel truss drainage system of the present invention.

[0022] Figure 5 This is a schematic diagram of the structure of the first and second lower collection pipes in an embodiment of a double-layer steel truss drainage system of the present invention.

[0023] In the diagram: 1. Upper drainage pipe; 11. Upper collection pipe; 111. Upper longitudinal collection pipe; 1111. Longitudinal collection pipe unit; 112. Web member drainage pipe; 113. Vertical guide pipe; 12. Upper drainage pipe; 121. Longitudinal drainage pipe; 122. Overflow pipe; 2. Upper chord of truss; 3. Lower chord of truss; 4. Lower drainage pipe; 41. Lower longitudinal drainage pipe; 42. Lower vertical guide pipe; 5. Diagonal web member of truss; 6. First lower collection pipe; 7. Second lower collection pipe. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0025] This application provides a double-layer steel truss drainage system and design method, which can solve the problem in the prior art that, in practical engineering applications, especially in coastal and mountainous areas where strong winds are frequent, when strong winds act on the bridge, the rainwater discharged from the overflow pipe of the upper bridge deck is blown to the inside of the bridge and falls directly to the lower bridge deck, which increases the burden on the lower drainage layer, affects the drainage speed, and may affect driving safety.

[0026] like Figure 1 and Figure 2 As shown, in one aspect, this application provides a double-layer steel truss drainage system, which includes: The upper drainage pipe 1 includes an upper water collection pipe 11 and an upper drainage pipe 12 with a set drainage capacity. The inlet of the upper water collection pipe 11 is located on the lower side of the upper chord 2 of the truss in the transverse direction. The upper water collection pipe 11 is connected to the upper drainage pipe 12. The upper drainage pipe 12 is located on the outer side of the lower chord 3 of the truss in the transverse direction. The lower drainage pipe 4 has its inlet located on the lower chord 3 of the truss and its outlet located on the lower side of the lower chord 3.

[0027] In designing this double-layer steel truss drainage system, the upper drainage pipe 1 includes an upper collection pipe 11 and an upper diversion drainage pipe 12 with a set drainage capacity. The inlet of the upper collection pipe 11 is located on the lower side of the upper chord 2 of the truss in the transverse direction. The upper collection pipe 11 is connected to the upper diversion drainage pipe 12, which is located on the outer side of the lower chord 3 of the truss in the transverse direction. The inlet of the lower drainage pipe 4 is located on the lower chord 3 of the truss, and the outlet is located below the lower chord 3. When designing the drainage capacity of the upper diversion drainage pipe 12, the rainfall threshold is first obtained based on the climate parameters of the bridge site area; then, the design flow rate of the upper bridge deck is obtained based on the catchment area and rainfall threshold of the upper bridge deck; finally, the drainage capacity of the upper diversion drainage pipe 12 is set according to the design flow rate of the upper bridge deck. By placing the upper-level drainage pipe 12 on the outer side of the lower chord 3 of the truss, rainwater from the upper bridge deck is directly discharged to the outer side of the bridge, preventing the phenomenon in traditional designs where overflowing rainwater from the upper deck is blown onto the lower bridge deck by strong winds. Furthermore, the upper-level drainage pipe 1 directs rainwater to the outer side of the lower chord 3 for discharge, while the lower-level drainage pipe 4 independently handles rainwater from the lower bridge deck. The two are completely separated spatially, avoiding the problem of mutual interference between upper and lower drainage systems in traditional designs. This solves the problem in existing technologies, especially in coastal and mountainous areas prone to strong winds, where rainwater discharged from the upper bridge deck overflow pipe is blown inwards by strong winds and falls directly onto the lower bridge deck, increasing the burden on the lower drainage system, affecting drainage speed, and potentially impacting traffic safety.

[0028] like Figure 5As shown, in this example, it also includes a first lower collection pipe 6 and a second lower collection pipe 7, which are connected to the drain outlets of the upper drainage pipe 12 and the lower drainage pipe 4, respectively, for collecting rainwater.

[0029] In this example, all parts of the upper drainage pipe 1 have the same diameter.

[0030] like Figure 1 and Figure 2 As shown, in some optional embodiments, the upper water collection pipe 11 includes: The upper longitudinal water collection pipe 111 has its inlet located on the lower side of the transverse bridge direction of the upper chord 2 of the truss beam; Multiple drainage pipes 112 with a web-like structure are connected at the upper end to the upper longitudinal water collection pipe 111 and at the lower end to the upper drainage pipe 12.

[0031] This embodiment specifically describes the structure of the upper-level water collection pipe 11. The upper-level water collection pipe 11 includes an upper-level longitudinal water collection pipe 111 and multiple web member drainage pipes 112. The inlet of the upper-level longitudinal water collection pipe 111 is located on the lower side of the upper chord 2 of the truss in the transverse direction. The upper end of the web member drainage pipe 112 is connected to the upper-level longitudinal water collection pipe 111, and the lower end is connected to the upper-level drainage pipe 12. The inlet of the upper-level longitudinal water collection pipe 111 is located on the lower side of the upper chord 2 of the truss in the transverse direction, making full use of the bridge deck cross slope design and gravity, allowing rainwater to flow naturally to the drainage system. This design avoids the water accumulation problem caused by unreasonable inlet location in traditional drainage systems, significantly improves rainwater collection efficiency, and ensures that rainwater on the bridge deck can enter the drainage system quickly and orderly. By setting multiple web member drainage pipes 112 to connect the upper-level longitudinal water collection pipe 111 and the upper-level drainage pipe 12, a segmented collection-centralized drainage mode is formed. This design breaks down the high-intensity water runoff on the upper bridge deck into multiple small-flow units, effectively avoiding the drainage problems caused by concentrated water runoff in traditional designs. It is particularly suitable for the drainage needs of wide bridge decks.

[0032] like Figure 1 As shown, in some optional embodiments, the upper longitudinal water collection pipe 111 includes the same number of longitudinal water collection pipe units 1111 as the web bar drainage pipes 112. The longitudinal water collection pipe units 1111 are spaced apart along the longitudinal bridge direction, and one end of the longitudinal water collection pipe unit 1111 is connected to the upper end of the corresponding web bar drainage pipe 112.

[0033] In this embodiment, the upper longitudinal water collection pipe 111 includes the same number of longitudinal water collection pipe units 1111 as the web stud drainage pipes 112. These units are spaced apart along the longitudinal direction of the bridge, with one end connected to the upper end of the corresponding web stud drainage pipe 112. When a section of the longitudinal water collection pipe unit 1111 experiences partial blockage or damage, the other units can still function normally, preventing the entire drainage system from failing. This modular design significantly improves the reliability and resilience of the drainage system, ensuring basic drainage functionality even under extreme weather conditions and saving valuable time for subsequent maintenance. Furthermore, double-layer steel truss bridges undergo complex structural deformations under vehicle loads, wind loads, and other conditions. The longitudinal water collection pipe units 1111 better adapt to these localized deformations, reducing the mutual constraints and stress transfer between the drainage system and the main bridge structure, thus protecting the drainage system and avoiding adverse effects on the bridge's structural safety.

[0034] like Figure 1 and Figure 2 As shown, in some optional embodiments, the upper water collection pipe 11 also includes a plurality of vertical guide pipes 113, with the inlet of one end of the vertical guide pipe 113 located on the lower side of the transverse direction of the upper chord 2 of the truss, and the other end connected to the upper longitudinal water collection pipe 111.

[0035] In this embodiment, the upper water collection pipe 11 also includes multiple vertical guide pipes 113. The inlet of one end of the vertical guide pipe 113 is located on the lower side of the transverse direction of the upper chord 2 of the truss, and the other end is connected to the upper longitudinal water collection pipe 111. The vertical guide pipe 113 directly connects the bridge deck and the longitudinal water collection pipe, forming a vertical drainage channel, which effectively shortens the rainwater flow path and improves the rainwater collection speed. Especially in the early stage of rainstorms and in the case of short-term heavy rainfall, it can quickly guide the water on the bridge into the drainage system, greatly reduce the time of water accumulation on the bridge, and effectively prevent traffic safety hazards caused by untimely drainage.

[0036] like Figure 1 , Figure 2 and Figure 4 As shown, in some optional embodiments, the upper drainage pipe 12 includes: The longitudinal drainage pipe 121 is installed along the lower chord of the truss 3 and is located on the outer side of the lower chord of the truss 3 in the transverse direction. The drain outlet of the longitudinal drainage pipe 121 is located on the lower side of the lower chord of the truss 3 in the longitudinal direction. Multiple overflow pipes 122 are connected to longitudinal drainage pipes 121 and are spaced apart along the length of longitudinal drainage pipes 121.

[0037] In this embodiment, the structure of the upper-level drainage pipe 12 is specifically described. The upper-level drainage pipe 12 includes a longitudinal drainage pipe 121 and multiple overflow pipes 122. The longitudinal drainage pipe 121 is arranged along the lower chord 3 of the truss and is located on the outer side of the lower chord 3 in the transverse direction. The drainage outlet of the longitudinal drainage pipe 121 is located on the lower side of the lower chord 3 in the longitudinal direction. The multiple overflow pipes 122 are connected to the longitudinal drainage pipe 121 and are spaced apart along the length of the longitudinal drainage pipe 121. By placing the longitudinal drainage pipe 121 on the outer side of the lower chord 3 in the transverse direction, rainwater is directly discharged to the outer side of the bridge. This external drainage design effectively prevents rainwater from the upper layer from falling to the lower bridge deck under strong winds, significantly improving the driving safety of the double-layer steel truss bridge under adverse weather conditions. The longitudinal drainage pipe 121 and the multiple spaced overflow pipes 122 form a coordinated drainage mechanism of main channel-auxiliary overflow. Under normal rainfall conditions, rainwater is mainly discharged in an orderly manner through the longitudinal drainage pipe 121; under conditions of excessive rainfall exceeding the design limit, the overflow pipe 122 automatically activates to share the drainage load. This design ensures both drainage efficiency under normal operating conditions and system safety under extreme weather conditions, significantly improving the reliability and adaptability of the drainage system.

[0038] like Figure 1 and Figure 2 As shown, in some optional embodiments, the lower drainage pipe 4 includes drainage units corresponding to the number of areas between the diagonal web members 5 of the truss beam, and the drainage units include: The lower longitudinal drainage pipe 41 is located below the lower transverse side of the area between the diagonal web members 5 of the truss beam; Multiple lower-level vertical water guide pipes 42 have their inlets located on the lower side of the transverse bridge direction of the lower chord 3 of the truss, and their other ends connected to the lower-level longitudinal drainage pipes 41.

[0039] In this embodiment, the lower-level drainage pipe 4 includes drainage units corresponding to the number of areas between the diagonal web members 5 of the truss. Each drainage unit includes a lower-level longitudinal drainage pipe 41 and multiple lower-level vertical guide pipes 42. The lower-level longitudinal drainage pipe 41 is located below the lower transverse side of the area between the diagonal web members 5. One end of each of the multiple lower-level vertical guide pipes 42 has its inlet located on the lower transverse side of the lower chord 3 of the truss, and the other end connects to the lower-level longitudinal drainage pipe 41. The number of drainage units corresponds to the number of areas between the diagonal web members 5, creating a natural match between the drainage system and the main bridge structure. This design fully utilizes the inherent structural zoning of the bridge, making the drainage system an integral part of the bridge structure. Each drainage unit is responsible for the drainage of its corresponding area, achieving a precise drainage mode of zoned collection and zoned discharge. This design avoids the inefficiency caused by excessively long drainage paths in traditional centralized drainage systems, significantly improving rainwater collection and discharge speed. Especially under heavy rain conditions, it can quickly eliminate water accumulation on the bridge surface, effectively ensuring traffic safety. Furthermore, the lower longitudinal drainage pipe 41 is located below the lower transverse side of the bridge in the area between the diagonal web members 5 of the truss, making full use of the bridge deck's cross slope and gravity to allow rainwater to flow naturally and efficiently to the drainage system. This design requires no additional power equipment, saving energy and improving the system's reliability and stability, ensuring good drainage performance under various operating conditions.

[0040] like Figure 1 and Figure 2 As shown, on the other hand, this application also provides a design method for a double-layer steel truss drainage system, which is used to design the above-mentioned double-layer steel truss drainage system, including the following steps: Based on the climate parameters of the bridge site area, rainfall thresholds were obtained; Based on the catchment area and rainfall threshold of the upper bridge deck, the design runoff of the upper bridge deck is obtained; The drainage volume of the upper-level drainage pipe 12 is set according to the design flow rate of the upper-level bridge deck.

[0041] In designing this double-layer steel truss drainage system, the upper drainage pipe 1 includes an upper collection pipe 11 and an upper diversion drainage pipe 12 with a set drainage capacity. The inlet of the upper collection pipe 11 is located on the lower side of the upper chord 2 of the truss in the transverse direction. The upper collection pipe 11 is connected to the upper diversion drainage pipe 12, which is located on the outer side of the lower chord 3 of the truss in the transverse direction. The inlet of the lower drainage pipe 4 is located on the lower chord 3 of the truss, and the outlet is located below the lower chord 3. When designing the drainage capacity of the upper diversion drainage pipe 12, the rainfall threshold is first obtained based on the climate parameters of the bridge site area; then, the design flow rate of the upper bridge deck is obtained based on the catchment area and rainfall threshold of the upper bridge deck; finally, the drainage capacity of the upper diversion drainage pipe 12 is set according to the design flow rate of the upper bridge deck. By placing the upper-level drainage pipe 12 on the outer side of the lower chord 3 of the truss, rainwater from the upper bridge deck is directly discharged to the outer side of the bridge, preventing the phenomenon in traditional designs where overflowing rainwater from the upper deck is blown onto the lower bridge deck by strong winds. Furthermore, the upper-level drainage pipe 1 directs rainwater to the outer side of the lower chord 3 for discharge, while the lower-level drainage pipe 4 independently handles rainwater from the lower bridge deck. The two are completely separated spatially, avoiding the problem of mutual interference between upper and lower drainage systems in traditional designs. This solves the problem in existing technologies, especially in coastal and mountainous areas prone to strong winds, where rainwater discharged from the upper bridge deck overflow pipe is blown inwards by strong winds and falls directly onto the lower bridge deck, increasing the burden on the lower drainage system, affecting drainage speed, and potentially impacting traffic safety.

[0042] In this example, according to the formula: Obtain the rainfall threshold, where, The rainfall threshold, For the recurrence period, For the time of flow, , The duration of flow at the slope is related to the cross slope i% of the bridge deck. The duration of the drainage flow is related to the longitudinal slope j% of the bridge deck.

[0043] According to the formula: , Obtain the design runoff volume for diversion on the upper bridge deck, where, Designed runoff volume for diverting traffic to the upper bridge deck. The runoff coefficient is taken as 0.95. The catchment area of ​​the upper bridge deck. The width of the upper bridge deck. The total length of all longitudinal water collection pipe units 1111.

[0044] In some optional embodiments, before obtaining the design runoff volume for diverting water from the upper bridge deck based on the catchment area and rainfall threshold of the upper bridge deck, the method further includes: Based on the total length of all longitudinal water collection pipe units 1111 and the width of the upper bridge deck, the water catchment area of ​​the upper bridge deck is obtained.

[0045] In this embodiment, before obtaining the design runoff volume of the upper bridge deck based on its catchment area and rainfall threshold, the method further includes: obtaining the catchment area of ​​the upper bridge deck based on the total length of all longitudinal water collection pipe units 1111 and the width of the upper bridge deck. Determining the effective catchment area based on the actual arrangement length of the longitudinal water collection pipe units 1111 makes the catchment area calculation more consistent with engineering realities, significantly improving the scientific rigor and accuracy of the design calculations.

[0046] In some optional embodiments, the method further includes setting the diameter of the lower vertical guide pipe 42, including: Based on the climate parameters of the bridge site area, the rainwater deflection angle was obtained; The design runoff of the lower bridge deck is obtained based on the rainwater deflection angle, the width of the upper bridge deck shielding, the bridge truss height, the width of the lower bridge deck, the full span length of the lower bridge deck, and the rainfall threshold. The diameter of the lower-level vertical guide pipe 42 is determined based on the design flow rate of the lower-level bridge deck.

[0047] In this embodiment, the solution also includes the step of setting the diameter of the lower vertical guide pipe 42, including: obtaining the rainwater deflection angle based on the climate parameters of the bridge site area; obtaining the design runoff of the lower bridge deck based on the rainwater deflection angle, the width of the upper bridge deck's obstruction, the bridge truss height, the width of the lower bridge deck, the total span length of the lower bridge deck, and the rainfall threshold; and setting the diameter of the lower vertical guide pipe 42 according to the design runoff of the lower bridge deck. By obtaining the rainwater deflection angle based on the climate parameters of the bridge site area, the actual impact of wind on the trajectory of rainwater is scientifically reflected. Based on parameters such as the rainwater deflection angle, the width of the upper bridge deck's obstruction, and the bridge truss height, the actual catchment width of the lower bridge deck is accurately calculated, truly reflecting the degree of obstruction of the upper bridge deck to the lower bridge deck. This avoids the overestimation or underestimation of the catchment area of ​​the lower bridge deck in traditional designs, providing a scientific basis for subsequent runoff calculations.

[0048] like Figure 3 As shown, in this example, according to the formula: Obtain the rainwater deflection angle, where, The angle of the rainwater deflection. For horizontal wind speed, This represents the terminal velocity of the rainwater.

[0049] According to the formula: , , , Obtain the design runoff of the lower bridge deck; among which, The runoff coefficient is taken as 0.95. The wind force influence coefficient. The rainfall threshold, This refers to the catchment area of ​​the lower bridge deck. This refers to the catchment width of the lower bridge deck. For the bridge truss height, The angle of the rainwater deflection. To shield the width of the upper bridge deck, The width of the lower bridge deck. This refers to the total span length of the lower bridge deck.

[0050] In some optional embodiments, obtaining the design runoff capacity of the lower bridge deck based on the rainwater deflection angle, the width of the upper bridge deck's obstruction, the bridge truss height, the width of the lower bridge deck, the total span length of the lower bridge deck, and the rainfall threshold includes: The water catchment width of the lower bridge deck is obtained based on the rainwater deflection angle, the width of the upper bridge deck's shielding, the bridge truss height, and the width of the lower bridge deck. The design runoff of the lower bridge deck is obtained based on the catchment width, total span length, width, and rainfall threshold of the lower bridge deck.

[0051] In this embodiment, the design runoff of the lower bridge deck is obtained based on the rainwater deflection angle, the width of the upper bridge deck's shielding, the bridge truss height, the width of the lower bridge deck, the total span length of the lower bridge deck, and the rainfall threshold. Specifically, this includes: obtaining the catchment width of the lower bridge deck based on the rainwater deflection angle, the width of the upper bridge deck's shielding, the bridge truss height, and the width of the lower bridge deck; and obtaining the design runoff of the lower bridge deck based on the catchment width, the total span length of the lower bridge deck, the width of the lower bridge deck, and the rainfall threshold. This two-stage method, which first calculates the actual catchment width of the lower bridge deck and then calculates the design runoff, accurately reflects the trajectory of rainwater under wind action and the shielding effect of the upper bridge deck on the lower bridge deck. This step-by-step calculation method conforms to the principles of fluid mechanics and meteorology, making the design calculations more consistent with actual physical processes and significantly improving the scientific nature and accuracy of drainage system design.

[0052] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0053] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0054] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A double-layer steel truss drainage system, characterized in that, include: The upper drainage pipe (1) includes an upper water collection pipe (11) and an upper drainage pipe (12) with a set drainage capacity. The inlet of the upper water collection pipe (11) is located on the lower side of the upper chord (2) of the truss. The upper water collection pipe (11) is connected to the upper drainage pipe (12). The upper drainage pipe (12) is located on the outer side of the lower chord (3) of the truss. The lower drainage pipe (4) has its inlet located on the lower chord (3) of the truss and its outlet located on the lower side of the lower chord (3).

2. The double-layer steel truss drainage system as described in claim 1, characterized in that, The upper water collection pipe (11) includes: The upper longitudinal water collection pipe (111) has its inlet located on the lower side of the transverse bridge direction of the upper chord (2) of the truss beam; Multiple brace drainage pipes (112) are provided, with the upper end of the brace drainage pipe (112) connected to the upper longitudinal water collection pipe (111) and the lower end connected to the upper drainage pipe (12).

3. A double-layer steel truss drainage system as described in claim 2, characterized in that, The upper longitudinal water collection pipe (111) includes the same number of longitudinal water collection pipe units (1111) as the web bar drainage pipe (112). The longitudinal water collection pipe units (1111) are spaced apart along the longitudinal bridge direction, and one end of the longitudinal water collection pipe unit (1111) is connected to the upper end of the corresponding web bar drainage pipe (112).

4. A double-layer steel truss drainage system as described in claim 2, characterized in that, The upper water collection pipe (11) also includes multiple vertical water guide pipes (113). The inlet of one end of the vertical water guide pipe (113) is located on the lower side of the transverse direction of the upper chord (2) of the truss, and the other end is connected to the upper longitudinal water collection pipe (111).

5. A double-layer steel truss drainage system as described in claim 1, characterized in that, The upper drainage pipe (12) includes: A longitudinal drainage pipe (121) is provided along the lower chord (3) of the truss and is located on the outer side of the lower chord (3) in the transverse direction. The drain outlet of the longitudinal drainage pipe (121) is located on the lower side of the lower chord (3) in the longitudinal direction. Multiple overflow pipes (122) are connected to the longitudinal drainage pipe (121) and are spaced apart along the length of the longitudinal drainage pipe (121).

6. A double-layer steel truss drainage system as described in claim 1, characterized in that, The lower drainage pipe (4) includes drainage units corresponding to the number of areas between the diagonal web members (5) of the truss beam, and the drainage unit includes: The lower longitudinal drainage pipe (41) is located below the lower transverse side of the area between the diagonal web members (5) of the truss beam; Multiple lower vertical guide pipes (42) have their inlets located on the lower side of the lower chord (3) of the truss in the transverse direction, and their other ends connected to the lower longitudinal drainage pipes (41).

7. A design method for a double-layer steel truss drainage system, characterized in that, For designing a double-layer steel truss drainage system as described in any one of claims 1-6, the following steps are included: Based on the climate parameters of the bridge site area, rainfall thresholds were obtained; Based on the catchment area and rainfall threshold of the upper bridge deck, the design runoff of the upper bridge deck is obtained; The drainage volume of the upper drainage pipe (12) is set according to the design flow rate of the upper bridge deck.

8. The design method for a double-layer steel truss drainage system as described in claim 7, characterized in that, Before obtaining the design runoff volume for diverting water from the upper bridge deck based on the catchment area and rainfall threshold of the upper bridge deck, the process also includes: The catchment area of ​​the upper bridge deck is obtained based on the total length of all longitudinal water collection pipe units (1111) and the width of the upper bridge deck.

9. The design method for a double-layer steel truss drainage system as described in claim 7, characterized in that, It also includes the step of setting the diameter of the lower vertical guide pipe (42), including: Based on the climate parameters of the bridge site area, the rainwater deflection angle was obtained; The design runoff of the lower bridge deck is obtained based on the rainwater deflection angle, the width of the upper bridge deck shielding, the bridge truss height, the width of the lower bridge deck, the full span length of the lower bridge deck, and the rainfall threshold. The diameter of the lower vertical guide pipe (42) is determined according to the design flow rate of the lower bridge deck.

10. The design method for a double-layer steel truss drainage system as described in claim 9, characterized in that, The method for obtaining the design runoff capacity of the lower bridge deck based on rainwater deflection angle, upper bridge deck obstruction width, bridge truss height, lower bridge deck width, lower bridge deck full span length, and rainfall threshold includes: The water catchment width of the lower bridge deck is obtained based on the rainwater deflection angle, the width of the upper bridge deck's shielding, the bridge truss height, and the width of the lower bridge deck. The design runoff of the lower bridge deck is obtained based on the catchment width, total span length, width, and rainfall threshold of the lower bridge deck.

Images