A cross-span structure for a four-track railway bridge
By using the cross-span structure of a four-track railway bridge, and by optimizing the pier design through double-layer portal piers and elevation adjustments, the problem of the difficult development and utilization of the land sandwiched between multiple railway crossings has been solved, thereby improving the comprehensive utilization rate of land and enhancing the aesthetics of railway engineering.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA RAILWAY ERYUAN ENGINEERING GROUP CO LTD
- Filing Date
- 2023-12-18
- Publication Date
- 2026-05-26
Smart Images
Figure CN117904943B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of railway bridges, and in particular to a cross-span structure for a four-track railway bridge. Background Technology
[0002] With the development of high-speed railway construction and the needs of urban development, the proportion of railway bridges on high-speed railway trunk lines has been continuously increasing. Simultaneously, in railway hub areas, multiple railways frequently intersect and cross each other. In past railway engineering designs, to avoid long-distance, small-angle line crossings, the intersection angle of the lines was often adjusted, sacrificing the original line alignment. However, this method has drawbacks, creating numerous "sandwiched" areas that are difficult to develop and utilize later, negatively impacting both railway land acquisition and demolition cost calculations and the actual implementation of land acquisition and demolition work. If the hub station is planned to be built in an urban area, the local land acquisition and demolition work during the implementation phase becomes extremely difficult and costly, and the railway project lacks aesthetic appeal. Therefore, to improve the comprehensive utilization rate of land and optimize the overall railway investment, and from the perspective of enhancing the aesthetics of railway engineering and facilitating project implementation, it is necessary to study a method for long-distance, small-angle crossings of four-track shared railway bridges. Summary of the Invention
[0003] The purpose of this invention is to provide a cross-span structure for a four-track railway bridge, addressing the problems existing in the prior art.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0005] A four-track railway bridge crossing structure includes tracks a and d connecting cities A and B, and tracks b and c connecting cities C and D. Tracks a and d enclose tracks b and c within the four-track shared passageway. Double-layer portal piers are installed within the four-track shared passageway. When the track spacing S between the lower and upper tracks is less than the track spacing St required for independently installed round-ended piers, the height difference ha between the two rail surfaces of the double-layer portal piers is greater than h1 + h2 + h3 + h4. Where h1, h2, h3, h4, and St are determined in the following manner:
[0006] Based on the rail surface elevation of the lower track at the crossing point, and to meet the safety distance requirements of the high-voltage charged body of the contact wire AF, the influence height range h1 of the contact wire is determined. A finite element model is established, and structural calculations are performed on a typical cross-section of the double-layer frame pier at the crossing point. Under the premise that the structure meets the various indicators required by the railway design specifications, the optimal structural height h2 of the upper cover beam is determined. According to the railway design standards, the applicable standard drawing (the general standard drawing issued by China State Railway Group Co., Ltd., hereinafter referred to as "the Ministry-issued drawing") for the beam section of the upper track at the crossing point is selected, and the distance h3 from the rail surface to the bottom of the corresponding beam section is found in the Ministry-issued beam drawing. The combined height h4 of the support pad stone of the ordinary simply supported beam of the upper track is determined comprehensively. According to the design standards, the applicable Ministry-issued drawing for the beam section of the lower track at the parallel section is selected, and the corresponding beam width parameter b1 is found. Based on design experience, the initial dimensions are proposed. The transverse dimension b2 of the pier neck is used to calculate whether the stress index and linear stiffness of the pier of this dimension meet the requirements of railway specifications under various working conditions. Then, the value of b2 is continuously iterated and corrected. The optimal transverse dimension b2 is when all the indexes meet the requirements of railway specifications and have a slight margin. The required line spacing St for independently set round-end piers is calculated: St = b1 / 2 + (b2 / 2 + (H-Δh) / m) - S1 / 2, where H is the calculated pier height determined by the terrain. Specifically, the pier heights of the selected spanning section are statistically analyzed based on the terrain and ground features, and the arithmetic mean pier height of the section is calculated as the calculated pier height H. Δh is the total height from the pier neck to the pier top of the independently set round-end piers on the above line. m is the slope ratio of the round-end pier. S1 is the double-line spacing of the above line.
[0007] As a preferred embodiment of the present invention, when the line spacing S between the lower line and the upper line is greater than or equal to the line spacing requirement St when independently setting round-ended piers, the lines a, b, c, and d are each set with round-ended piers separately.
[0008] As a preferred embodiment of the present invention, the pier caps of two adjacent round-ended piers can be repaired together.
[0009] As a preferred embodiment of the present invention, when the distance between two adjacent lines continuously decreases, the longitudinal profile of one line gradually decreases while the longitudinal profile of the other line gradually increases, forming a relative height difference and creating conditions for crossing.
[0010] As a preferred embodiment of the present invention, the double-layer portal pier is a prestressed concrete structure.
[0011] As a preferred embodiment of the present invention, the double-layer portal pier has a double-line upper layer and a single-line lower layer.
[0012] As a preferred embodiment of the present invention, a line station is provided within the range of the four-line common channel.
[0013] As a preferred embodiment of the present invention, cities A, B, C, and D are respectively provided with parking lots / stations.
[0014] In a preferred embodiment of the present invention, two adjacent parking lots are arranged in parallel and are located at the same station.
[0015] As a preferred embodiment of the present invention, a cutting wing design is carried out between the beams when two adjacent lines run parallel.
[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0017] This invention can effectively improve the comprehensive utilization rate of land, optimize the overall investment in railways, enhance the aesthetics of railway projects, and facilitate project implementation. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the cross-span structure of the four-track railway bridge described in this invention. Figure 1 .
[0019] Figure 2 This is a schematic diagram of the cross-span structure of the four-track railway bridge described in this invention. Figure 2 .
[0020] Figure 3 This is a schematic diagram illustrating the calculation parameters for the height difference between the two rail surfaces as described in this invention.
[0021] Figure 4 This is a schematic diagram of the calculation parameters for the line spacing requirements described in this invention.
[0022] Figure 5 This is a schematic diagram of the structure of the line repair section (point 1) of the present invention.
[0023] Figure 6 This is a structural schematic diagram of the single-line frame pier (bridge) (point 2) of the present invention.
[0024] Figure 7 This is a structural schematic diagram of the single-line frame pier (bridge) (point 3) of the present invention.
[0025] Figure 8 This is a structural schematic diagram of the single-line frame pier (bridge) (point 4) of the present invention.
[0026] Figure 9 This is a structural schematic diagram of the single-line frame pier (bridge) (point 5) of the present invention.
[0027] Figure 10 This is a structural schematic diagram of the maintenance point (bridge) (point 6) of the line of the present invention.
[0028] Figure 11 This is a schematic diagram showing the distribution range of portal pier segment types according to the present invention.
[0029] Icons: 1 - Four-line common channel range, 2 - Line junction. Detailed Implementation
[0030] The present invention will now be described in detail with reference to the accompanying drawings.
[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0032] Example 1
[0033] like Figure 1-2 As shown, a cross-span structure of a four-track railway bridge is used to connect cities A, B, C, and D, including track a (connecting cities A and B), track b (connecting cities C and D), track c (connecting cities C and D), and track d (connecting cities A and B).
[0034] Line a and d form a crossing structure. Within the four-line shared passage 1, lines a and d enclose lines b and c. Double-layer portal piers are installed within the four-line shared passage 1. When the track spacing S between the lower and upper lines is less than the track spacing requirement St when independently installed with round-ended piers, the height difference ha between the two rail surfaces of the double-layer portal pier is greater than h1 + h2 + h3 + h4. Where h1, h2, h3, h4, and St are determined in the following way:
[0035] Using the rail surface elevation of the crossing point below the track level as a benchmark, and meeting the safety distance requirements of the AF high-voltage charged body of the contact wire, the influence height range h1 of the contact wire is determined. In actual construction, a circle with a radius of 3m (safe distance of charged body) can be drawn with the AF high-voltage charged body of the contact wire structure as the center. The height from the top of the circle to the rail surface is the influence height h1 of the contact wire. A finite element model is established, and structural calculations are performed on a typical cross-section of the double-layer frame pier at the crossing point. Under the premise that the structure meets the various indicators required by the railway design specifications, the optimal structural height h2 of the upper cover beam is determined. According to the railway design standards, the height h2 of the upper cover beam at the crossing point is selected. Refer to the standard drawing applicable to the beam section of the upper line (the general standard drawing issued by China State Railway Group Co., Ltd., hereinafter referred to as "Ministry-issued drawing"). Find the distance h3 from the rail surface to the bottom of the beam in the Ministry-issued beam drawing. Determine the combined height h4 of the support pad for the ordinary simply supported beam of the upper line. In actual construction, the combined height h4 of the support pad = support height + mortar height + pad height. Based on the beam type of the ordinary standard simply supported beam of the upper line, find the matching Ministry-issued drawing to obtain the support pier location and support structure height. Considering the mortar thickness of 2-3 cm and the bearing height requirement of the pad, a 5 cm value can be taken as a comprehensive value. The value of h4 is taken as a multiple of the design standard; the applicable design drawings for the parallel section located on the lower line beam are selected according to the design standard, and the corresponding beam width parameter b1 is queried; the transverse dimension b2 of the double-track pier neck is calculated and determined. In actual construction, the beam type of the ordinary standard simply supported beam on the upper line can be used to query the matching design drawings to obtain the magnitude of various loads transmitted from the superstructure. Based on design experience, the transverse dimension b2 of the pier neck is initially proposed. The stress indexes and linear stiffness of the pier of this dimension are tested under various working conditions to see if they meet the requirements of the railway specifications. Then, the value of b2 is continuously iteratively corrected to ensure that all indicators meet the requirements. The optimal transverse bridge dimension b2 is achieved when it meets the railway specification requirements with a slight margin. The required track spacing St for independently installed round-ended piers is calculated as follows: St = b1 / 2 + (b2 / 2 + (H - Δh) / m) - S1 / 2, where H is the calculated pier height determined by the terrain. Specifically, this involves statistically analyzing the pier heights within the selected spanning section based on terrain and features, calculating the arithmetic mean pier height as H, Δh is the total height from the pier neck to the pier top of the independently installed round-ended pier, m is the slope ratio of the round-ended pier, and S1 is the double-track spacing of the above-mentioned line. For example... Figure 3-4 As shown.
[0036] Based on the terrain, the crossing sections are comprehensively selected for alignment control. Specifically, line a gradually approaches line b, the distance between the two lines continuously decreases, and each line is independently equipped with round-ended piers (to further save crossing space, the substructure abutments can be combined). Simultaneously, the longitudinal profile of line a gradually decreases, while the longitudinal profiles of lines b and c gradually increase, gradually forming a relative elevation difference that meets the requirements, creating conditions for crossing. When the distance between the lower and upper lines is less than St and their relative elevation difference ha > h1 + h2 + h3 + h4, portal piers are rationally used to complete the crossing transition, based on the terrain and engineering distribution of line a.
[0037] When the distance between the lower and upper lines is greater than St, round-ended piers are set up independently, and lines a and d merge. The distance between their lines continuously decreases. When the distance between lines a and d decreases to 5m, the conditions for building a double track are met (the standard distance between double track beams in the Ministry-issued drawings is 5m). Here, the two single tracks are merged into a double track railway, thus completing the crossing of the entire line.
[0038] In one or more embodiments, the double-layer portal pier is a prestressed concrete structure.
[0039] In one or more embodiments, the double-layer portal pier has a double-line upper layer and a single-line lower layer structure.
[0040] In one or more embodiments, a junction 2 is provided within the four-line shared corridor area to facilitate the exchange of cross-line traffic. The compact arrangement of the junction 2 reduces land occupation, minimizes urban fragmentation, and reduces engineering investment.
[0041] In one or more embodiments, cities A, B, C, and D are each provided with a depot / station to meet the needs of cities A and B to gather at one station 1 for stopping and passing operations. Furthermore, depot 1 and depot 2 can be arranged in parallel at this station to allow the two depots to operate independently and avoid cross-interference operations.
[0042] In one or more embodiments, a cutting wing design is implemented between the beams when two adjacent lines run parallel.
[0043] The railway bridge of this invention optimizes the structure and adjusts the elevation of the line to minimize the area between the four parallel lines, significantly improves the comprehensive utilization rate of land, optimizes investment, and creates a magnificent structure with good landscape effect.
[0044] (1) When the AB city line is outsourced to the CD city line, and the AB city line does not need to cross the CD city line, the single line to be crossed is lowered by reducing the longitudinal section elevation of the rail surface, and the double line to be crossed is raised by increasing the longitudinal section elevation of the rail surface, in order to make full preparations for the subsequent interchange crossing. At the same time, the design adopts separate setting of single-column reinforced concrete round-end piers to save on structural investment.
[0045] (2) When the AB city line needs to cross the CD city line, the crossing of one of the single lines is achieved by lowering the longitudinal section elevation of the track surface and reducing the line spacing with the single line of the adjacent CD city line. The double line of the CD city line and the single line of the AB city line are combined to set up double-layer prestressed concrete portal piers (two on top and one on the bottom) to meet the structural limits while achieving a better landscape effect.
[0046] (3) After the AB city line crosses the CD city line, the AB city double line is changed from the form of being outsourced to the CD city double line to the form of running parallel to the CD city line. Each line is independently equipped with a single-column reinforced concrete round-end pier, which saves on structural investment and thus realizes the function of the AB city line and the CD city line crossing and running parallel.
[0047] Example 2
[0048] Based on Example 1, the combined double-layer portal piers of the Guangzhou-Zhanjiang High-speed Railway, which are introduced to the Pearl River Delta Airport and cross the Zhuhai-Zhaoqing High-speed Railway, are taken as an example.
[0049] At the Huilong elevated gate station, the left and right lines of the Zhuhai-Zhaoqing High-Speed Railway maintain an 8-meter track spacing with the Guangzhou-Zhanjiang High-Speed Railway (the parallel section features a cut-wing design between the beam sections). After leaving the gate station, the longitudinal profile of the Guangzhou-Zhanjiang High-Speed Railway gradually rises. Simultaneously, the distance between the left and right lines of the Guangzhou-Zhanjiang High-Speed Railway continuously decreases, creating conditions for the Guangzhou-Zhanjiang High-Speed Railway to cross the left line of the Zhuhai-Zhaoqing High-Speed Railway (considering the safety distance requirements of the high-voltage charged body of the contact wire AF, when the track spacing is less than 4.578m, the rail surface elevation difference between the left line of the Zhuhai-Zhaoqing High-Speed Railway and the main line of the Guangzhou-Zhanjiang High-Speed Railway needs to reach 15.040m). At kilometer marker DK74+542 of the Guangzhou-Zhanjiang High-Speed Railway (after crossing Provincial Highway S272), portal piers are used to cross the left line of the Zhuhai-Zhaoqing High-Speed Railway. As the railway approaches the Pearl River Delta hub airport, the left line of the Zhuhai-Zhaoqing High-Speed Railway gradually merges with the right line, and at kilometer marker DK77+160, the main line of the Guangzhou-Zhanjiang High-Speed Railway completes the crossing of the left line of the Zhuhai-Zhaoqing High-Speed Railway (the total length of the bridge requiring frame piers is approximately 2.7km). Subsequently, the track spacing between the left and right lines of the Zhuhai-Zhaoqing High-Speed Railway was further reduced to 5 meters, transitioning from single-track operation to double-track operation, running parallel to the Guangzhou-Zhanjiang mainline and connecting to the Pearl River Delta hub airport. The specific calculation steps are as follows:
[0050] Step 1: Using the elevation of the left track surface of the Zhuhai-Zhaoqing High-speed Railway located below the crossing point as the benchmark, and taking the AF high-voltage live body of the contact wire structure as the center, draw a circle with a radius of 3m (safe distance of live body). The height from the top of the circle to the track surface is the influence height of the contact wire, and the influence height range of the contact wire live body is 7.9m.
[0051] Step 2: Establish a finite element model and perform structural calculations on the typical cross-section of the double-layer frame pier at the crossing point. Under the premise that the structure meets the requirements of the railway design specifications, determine that the optimal structural height of the upper cover beam is 2.5m.
[0052] Step 3: According to the design standards, select the applicable design for the Guangzhan High-speed Railway with a 350 km / h precast ballastless track and post-tensioned prestressed concrete simply supported box girder (double track) with a crossover point located on the upper track. The distance from the rail surface to the bottom of the beam is 4.090m.
[0053] Step 4: Determine the height of the support pad stone for the ordinary simply supported beam of the Guangzhou-Zhanjiang High-speed Railway as 0.55m.
[0054] Step 5: Calculate the required longitudinal section elevation difference of the rail surface when setting the double-layer portal pier crossing, h1+h2+h3+h4=15.040m.
[0055] Step Six: According to the railway design standards, select the single-track applicable drawing of the Zhuhai-Zhaoqing High-speed Railway with a speed of 350 km / h, which is a precast ballastless track, post-tensioned prestressed concrete simply supported box girder (single track). The corresponding beam width parameter is 7.4m.
[0056] Step 7: Based on the above-mentioned line drawings, find the magnitude of various loads transmitted from the superstructure. Combining design experience, initially calculate the transverse dimension of the pier neck as 6.2m for control calculations. Then, continuously iterate and correct, and calculate that the optimal transverse dimension of the pier neck for the round-ended pier of the Guangzhou-Zhanjiang High-speed Railway is 6m. Select a pier slope ratio of 45:1 (a common pier slope ratio for high-speed railways with a speed of 350 km / h). Calculate the required line spacing St when independently setting up round-ended piers: St = 7.4 / 2 + (6 / 2 + (H-3) / 45) - 5 / 2 = 4.578. (H is the calculated pier height determined by the terrain. Specifically, based on the terrain and features, the pier heights within the selected span section are statistically analyzed, and the arithmetic mean pier height within that section is calculated as the calculated pier height H. Δh is the total height from the pier neck to the top of the independently set up round-ended pier of the Guangzhou-Zhanjiang High-speed Railway, and m is the slope ratio of the round-ended pier.)
[0057] Step 8: Based on the determined elevation difference of 15.040m for setting up double-layer portal piers and the control line spacing of 4.578m for independently set up round-ended bridge piers, it is concluded that when the line spacing S between the lower line of the Zhuhai-Zhaoqing High-speed Railway (left line) and the upper line of the Guangzhou-Zhanjiang High-speed Railway (left line) is less than 4.578m, the elevation difference ha between the two railway tracks must be greater than 15.040m.
[0058] A schematic diagram of the cross-section of the key points of the bridge is shown below. Figure 5-10 The evolution is shown below. The distribution range of portal pier segment types is as follows: Figure 11 As shown.
[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A cross-span structure for a four-track railway bridge, characterized in that, The four lines include lines a and d connecting cities A and B, and lines b and c connecting cities C and D. Within the four-line common channel range (1), lines a and d enclose lines b and c, and double-layer portal piers are set up within the four-line common channel range (1). When the line spacing S between the lower and upper lines is less than the line spacing requirement St when independently setting up round-ended piers, the height difference ha between the two rail surfaces of the double-layer portal pier is greater than h1+h2+h3+h4. Among them, h1, h2, h3, h4 and St are determined in the following way: Based on the track elevation of the lower track at the crossing point, and to meet the safety distance requirements of the high-voltage live conductor of the contact network AF, the influence height range h1 of the contact network is determined; a model is established, and structural calculations are performed on the typical cross-section of the double-layer frame pier at the crossing point to determine the structural height h2 of the upper cover beam; according to the design standards, the applicable departmental beam drawing for the upper track at the crossing point is selected, and the distance h3 from the track surface to the bottom of the beam in the corresponding beam drawing is found; the combined height h4 of the simply supported beam support pad for the upper track is determined; according to the design standards, the applicable departmental beam drawing for the lower track at the parallel point is selected, and the beam width parameter b1 in the corresponding beam drawing is found; the transverse dimension b2 of the pier neck of the double-track bridge is calculated and determined; the line spacing requirement St when independently setting round-end piers is calculated, St=b1 / 2+(b2 / 2+(H-Δh) / m)-S1 / 2, where H is the calculated pier height determined in combination with the terrain, Δh is the total height from the pier neck to the pier top, m is the slope ratio of the pier slope, and S1 is the double-track line spacing of the upper track.
2. The crossing structure of a four-track railway bridge according to claim 1, characterized in that, When the line spacing S between the lower line and the upper line is greater than or equal to the line spacing requirement St when independently setting round-ended piers, the lines a, b, c, and d shall be set with round-ended piers separately.
3. The crossing structure of a four-track railway bridge according to claim 2, characterized in that, The foundations of two adjacent round-ended piers are constructed together.
4. The crossing structure of a four-track railway bridge according to claim 1, characterized in that, When the distance between two adjacent lines continuously decreases, the longitudinal profile of one line gradually decreases while the longitudinal profile of the other line gradually increases, forming a relative elevation difference and creating conditions for crossing.
5. The crossing structure of a four-track railway bridge according to claim 1, characterized in that, The double-layer portal pier is a prestressed concrete structure.
6. The crossing structure of a four-track railway bridge according to claim 5, characterized in that, The double-layer portal pier has a double-line upper layer and a single-line lower layer structure.
7. The crossing structure of a four-track railway bridge according to claim 1, characterized in that, A line junction (2) is set up within the four-line common channel area.
8. The crossing structure of a four-track railway bridge according to claim 1, characterized in that, The cities A, B, C, and D are each equipped with parking lots / stations.
9. The crossing structure of a four-track railway bridge according to claim 8, characterized in that, The two adjacent depots are arranged in parallel and are located at the same station.
10. A cross-span structure for a four-track railway bridge according to any one of claims 1-9, characterized in that, Cutting flanges are designed and constructed between the beam sections of two adjacent lines.