Large-span different-layer small-angle intersecting steel truss connecting structure and method

Abstract

The application discloses a kind of super-span different layer small-angle intersection steel truss connecting structure and method, for reliably connecting box type multilayer truss and box type single-layer truss with small-angle intersection, simultaneously connect box type lateral secondary truss with two pieces of main truss with small-angle intersection;In the application, multilayer truss chord and single-layer truss chord with small-angle intersection are configured into special-shaped cross-section intersection combined chord, the flange of combined chord is widened and extended, which avoids stress concentration problem in small-angle intersection area of bar, disperses the weld intersection of node central position dense truss bar, and reduces stress concentration in the intersection position of 3 trusses;By using spatial staggered intersection non-intersection mode to set multilayer truss intersection diagonal web member and single-layer truss intersection diagonal web member, the intersection collision and weld intersection overlap of multiple diagonal web members are avoided, the truss load transmission path is ensured to be clear and simple, and the force transmission requirement of intersection node is met.

Description

Technical Field

[0001] This invention relates to the technical field of steel structure construction, and in particular to a small-angle cross steel truss connection structure and method with ultra-large span and different number of floors. Background Technology

[0002] With the booming development of modern large-span public buildings, the spatial layout of large public buildings is becoming increasingly complex. In pursuit of functionality and visual impact, architecture demands that structures not only cover column-free spaces exceeding 100 meters in span but also achieve spatial division between different upper and lower levels. This demand has directly driven the widespread application of large-span steel truss systems. The complex support requirements place higher demands on the load-bearing capacity, stiffness, and deformation of large-span truss systems. In particular, column-supporting trusses that simultaneously cover the lower large-span space and support the upper structure should ideally be designed as multi-layered trusses to ensure the structural system's safety and reliability. The complex spatial division leads to the use of steel trusses with varying spans, numbers of stories, and orientations in the supporting truss system. Furthermore, this results in truss systems intersecting at small angles, forming small-angle intersecting steel truss connection nodes with different numbers of stories across ultra-large spans.

[0003] The nodal area bears internal forces from truss members in multiple planes and at different angles, as well as enormous concentrated forces from the upper spatial structural columns, resulting in an extremely complex stress state. Traditional connection methods typically use a truss chord in one direction as the main member, with the remaining web members and chord members welded to the main member. However, the applicant's stress analysis revealed that this traditional connection method easily leads to severe stress concentration in areas where multiple members intersect at small angles, causing structural failure even under loads far below the bearing capacity, making it difficult to guarantee connection strength. Furthermore, with traditional connection methods, different truss diagonal web members are prone to crossing and colliding, and the welds of multiple members in the nodal area overlap and intersect, making it difficult to guarantee welding quality. Summary of the Invention

[0004] This invention provides a small-angle cross steel truss connection structure and method with ultra-large span and different number of layers.

[0005] The technical problems to be solved are: the difficulty in constructing small-angle intersection nodes in multi-layer trusses; the problem that stress concentration is prone to occur in areas where multiple members intersect at small angles using traditional connection methods, making it difficult to guarantee connection strength; and the problem that when the connection meets the strength requirements, the node design is often very large, and assembly and welding are difficult to achieve. At the same time, the problems of collision between diagonal web members of different trusses and overlapping welds of multiple members in traditional connection methods, making it difficult to guarantee weld quality, should also be addressed.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention relates to a small-angle intersecting steel truss connection structure with different spans and layers, used to reliably connect multi-layer trusses with small-angle intersections to single-layer trusses. It includes an intersecting lower chord, an intersecting upper chord, a central straight web member, multi-layer truss intersecting diagonal web members, multi-layer truss web members, single-layer truss intersecting diagonal web members, and single-layer truss web members. The central web member serves as a shared straight web member for the two trusses and is located at the center point of the intersection of the multi-layer truss and the single-layer truss. Its upper and lower ends are fixedly connected to the intersecting upper chord and the intersecting lower chord, respectively. The cross-combined lower chord has the same structure as the cross-combined upper chord. The cross-combined lower chord is connected in the direction of the lower chord of the multi-layer truss. The lower chord of the single-layer truss is broken at the intersection with the lower chord of the multi-layer truss and is fixedly connected to the lower chord of the multi-layer truss at the intersection edge. The flange plate of the cross-combined lower chord is divided into an intermediate flange plate along the direction of the multi-layer truss chord and a lateral flange plate along the direction of the single-layer truss chord. The lateral flange plate extends beyond the lateral inner web and lateral outer web of the single-layer truss lower chord, extending inward to the side wall of the intermediate web of the multi-layer truss lower chord and fixedly connected to the side wall, and extending outward to the minimum width of the cross-combined lower chord section, which is not less than the sum of the flange widths of the multi-layer truss lower chord and the single-layer truss lower chord. The cross diagonal web members of the multi-layer truss and the cross diagonal web members of the single-layer truss are aligned with the outer side of the central straight web member at their connection points.

[0007] This invention relates to a small-angle cross steel truss connection structure with ultra-large span and different number of layers. Further, the web of the multi-layer truss in the direction of the chord is referred to as the intermediate web, and the web of the single-layer truss close to the intermediate web is referred to as the lateral inner web, and the web far from the intermediate web is referred to as the lateral outer web. The intermediate web extends upward and downward from the flange of the multi-layer truss chord by a distance equal to the thickness of the intermediate web.

[0008] The present invention relates to a small-angle cross steel truss connection structure with a large span and different number of layers. Furthermore, a certain spacing of distributed stiffening plates is provided between the two intermediate webs in the disconnected area of ​​the lateral inner web and the lateral outer web. The distributed stiffening plates are fixedly connected perpendicular to the inner wall of the intermediate web and the intermediate flange.

[0009] The present invention relates to a small-angle cross steel truss connection structure with ultra-large span and different number of layers. Furthermore, the lower chord cavity of the cross combination is provided with connecting stiffening plates at the corresponding member connection positions of each truss. The connecting stiffening plates are perpendicular to the inner wall of the lower chord cavity of the cross combination and are fixedly connected to the inner wall of the lower chord cavity of the cross combination.

[0010] The present invention relates to a small-angle cross steel truss connection structure with a large span and different layers. Furthermore, the upper end of the cross diagonal web member of the multi-layer truss is fixedly connected to the intersection of the cross combination upper chord and the central straight web member, and extends from the upper end of the central straight web member along the direction of the multi-layer truss to both sides, and the lower end is fixedly connected to the intersection of the cross combination lower chord and the multi-layer truss web member. The lower end of the single-layer truss cross diagonal web member is fixedly connected to the intersection of the cross combination lower chord and the central straight web member, and extends from the lower end of the central straight web member along the direction of the single-layer truss to both sides, and the upper end is fixedly connected to the intersection of the cross combination upper chord and the single-layer truss web member.

[0011] This invention relates to a small-angle cross steel truss connection structure with ultra-large span and different number of layers. Furthermore, the cross-sectional width of the central straight web member is increased, and the cross diagonal web members of the multi-layer truss and the cross diagonal web members of the single-layer truss are aligned with the outer side of the central straight web member at their connection positions.

[0012] The present invention relates to a small-angle cross steel truss connection structure with a large span and different number of layers. Furthermore, lateral secondary trusses are connected on both sides of the main truss formed by the connection of multi-layer trusses and single-layer trusses. The lateral secondary trusses are fixedly connected to the intersection of the cross combined chord and the central straight web member of the main truss.

[0013] This invention relates to a small-angle cross steel truss connection structure with ultra-large span and different number of layers. Further, the lateral secondary truss includes lateral secondary truss chords and lateral secondary truss web members. The cross-combined lower chord is provided with chord connecting plates on both sides of the center point where the multi-layer truss and single-layer truss intersect. The chord connecting plates are arranged along the direction of the lateral secondary truss and are fixedly connected to the cross-combined lower chord. The lateral secondary truss chords are fixedly connected to the edges of the lateral flange plates and the chord connecting plates.

[0014] The present invention relates to a small-angle cross steel truss connection structure with a large span and different number of layers. Furthermore, the diagonal web members of each truss are subjected to end-expansion treatment at the fixed connection positions at both ends.

[0015] The present invention discloses a construction method, comprising the following steps: Step 1: Install the middle flange plate and a middle web plate of the cross-combined lower chord. Install the distribution stiffening plate and the connecting stiffening plate between the middle flange plates, and weld the distribution stiffening plate and the connecting stiffening plate to the middle flange plate respectively. Then install the other middle web plate. Step 2: Install the inner lateral web between the lateral flanges and weld it in place. Then weld the lateral flanges and the inner lateral web to the intermediate web at the connection point. Install the connecting stiffening plate between the lateral flanges and weld it to the lateral flanges. Then install the outer lateral web. Step 3: Install the cross-combined upper chord in the same manner; Step 4: Weld the lower end of the central straight web member to the center of the upper surface of the cross-combined lower chord member, and weld the lower ends of the multi-layer truss web members and single-layer truss web members to the upper surface of the cross-combined lower chord member in sequence from left to right outwards. Step 5: Install the cross-combined upper chord directly above the lower chord of the cross-combined structure, and weld and fix the upper ends of the installed central straight web members, multi-layer truss web members, and single-layer truss web members to the lower surface of the cross-combined upper chord. Step 6: Fix the two ends of the cross diagonal web members of the multi-layer truss to the intersection of the cross combination upper chord and the multi-layer truss web members, and the intersection of the cross combination lower chord and the central straight web member, respectively. Step 7: Fix the two ends of the single-layer truss cross diagonal web members to the intersection of the cross combination lower chord and the single-layer truss web members, and the intersection of the cross combination upper chord and the central straight web member, respectively.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. By constructing a cross-sectional composite chord with multi-layer truss chords that intersect at small angles and single-layer truss chords, and by widening and extending the flanges of the composite chords, the stress concentration problem in the small-angle intersection area of ​​the members is avoided. At the same time, after the flanges are widened, the dense intersection of truss members at the node center is dispersed, the overlapping of welds is reduced, and the stress concentration at the intersection of the three trusses is reduced. 2. Install distributed stiffening plates to reinforce the broken positions of the lower chord of the single-layer truss in the cross-combined chord to ensure the continuous load transfer of the single-layer truss chord; 3. By dividing the flange plate of the cross-combined lower chord into an intermediate flange plate and a lateral flange plate using an intermediate web plate, the problem of small welding space between the internal web plate and flange of the cross-combined lower chord, and between the stiffening plate and the inner wall of the member, is solved, thus ensuring welding quality; 4. The innovative cross-combined chords and central straight web members together form a robust three-dimensional force transmission core. By constructing a large-section central straight web member, and simultaneously using a spatially staggered, non-intersecting cross-web member arrangement for single-layer and multi-layer truss cross-web members, it ensures that loads from the truss in three directions can be clearly and directly transmitted, avoiding the ambiguity or detours that may occur in traditional nodes; it also avoids the convergence and collision of multiple diagonal web members and the overlapping of welds, ensuring a clear and non-concentrated load transmission path for the truss.

[0017] The invention will now be further described with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a small-angle cross-connection node structure for a large-span steel truss with different numbers of layers according to the present invention; Figure 2This is an isometric schematic diagram of the interconnections between the various truss members; Figure 3 This is a top view of the lower chord position; Figure 4 This is a side view of the position of the central straight web member.

[0019] Figure label: 1. Cross-combined lower chord; 11. Intermediate flange plate; 12. Lateral flange plate; 13. Intermediate web plate; 14. Lateral inner web plate; 15. Lateral outer web plate; 16. Distributed stiffening plate; 17. Connecting stiffening plate; 18. Chord connecting plate; 2. Cross-combined upper chord; 3. Central straight web member; 4. Multi-layer truss; 41. Multi-layer truss cross-diagonal web member; 42. Multi-layer truss web member; 43. Multi-layer truss upper web member; 5. Single-layer truss; 51. Single-layer truss cross-diagonal web member; 52. Single-layer truss web member; 6. Lateral secondary truss; 61. Lateral secondary truss chord member; 62. Lateral secondary truss web member. Detailed Implementation

[0020] like Figure 1 As shown, the present invention discloses a connection structure and method for small-angle intersecting steel trusses with different numbers of layers in an ultra-large span, which is used to reliably connect the multi-layer truss 4 with the single-layer truss 5 with small-angle intersections, and at the same time connect the lateral secondary truss 6 with the two main trusses with small-angle intersections.

[0021] Here, the multi-layer truss 4, the single-layer truss 5, and the lateral secondary truss 6 intersect at a single point. The single-layer truss 5 and the lateral secondary truss 6 intersect with the lower chord and middle chord of the multi-layer truss 4. In this embodiment, all three truss members are box-shaped, and the upper part of the multi-layer truss 4 supports the roof space frame.

[0022] like Figure 1-2 As shown, the connecting structure includes a cross-combined lower chord 1, a cross-combined upper chord 2, a central straight web member 3, a multi-layer truss cross-diagonal web member 41, a multi-layer truss web member 42, a multi-layer truss upper web member 43, a single-layer truss cross-diagonal web member 51, a single-layer truss web member 52, and a lateral secondary truss 6.

[0023] The cross-combined lower chord 1 is located at the lower chord position of the multi-layer truss 4 and the single-layer truss 5. It is an irregularly shaped cross-section composite chord constructed by the intersection of the lower chord of the multi-layer truss and the lower chord of the single-layer truss at a small angle. Similarly, the corresponding upper chord position is denoted as the cross-combined upper chord 2. The central straight web member 3 is located at the center point of the intersection of the multi-layer truss 4 and the single-layer truss 5. Its upper and lower ends are fixedly connected to the cross-combined upper chord 2 and the cross-combined lower chord 1, respectively, serving as a common straight web member for the two trusses. The lateral secondary truss 6 is fixedly connected at the intersection of the cross-combined chord and the central straight web member 3, including the lateral secondary truss chord 61 and the lateral secondary truss web member 62.

[0024] like Figure 3As shown, the lower chord 1 of the cross-combined structure is connected in the direction of the lower chord of the multi-layer truss 4. The web of the lower chord of the single-layer truss 5 is broken at the intersection. The web along the chord direction of the multi-layer truss 4 is designated as the intermediate web 13, the web along the chord direction of the single-layer truss 5 that is closer to the intermediate web 13 is designated as the lateral inner web 14, and the web further away from the intermediate web 13 is designated as the lateral outer web 15. To ensure the welding space and welding quality of the welds of the inner web and stiffening plates of the cross-combined lower chord 1, the intermediate web 13 extends upward and downward by a distance equal to the thickness of one web plate, dividing the flange of the cross-combined lower chord 1 into the intermediate flange 11 along the chord direction of the multi-layer truss 4 and the lateral flange 12 along the chord direction of the single-layer truss 5. The webs and flanges are fixedly connected at the intersection edge.

[0025] To disperse the truss load and members, and reduce stress concentration at the intersection of the three trusses, the lateral flange plate 12 of the lower chord 1 of the cross combination extends beyond the lateral inner web plate 14 and the lateral outer web plate 15, extending inward to the side wall of the middle web plate 13 and being fixedly connected to the side wall, and extending outward to the minimum width of the cross combination lower chord 1 section is not less than the sum of the flange widths of the lower chord of the multi-layer truss 4 and the lower chord of the single-layer truss 5; at the same time, after the cross combination lower chord 1 section width is extended, the truss members at the intersection of the three trusses are dispersed, reducing the overlap of welds and further ensuring welding quality.

[0026] To ensure continuous load transmission in the lower chord of the single-layer truss 5, the cross-combined lower chord 1 has distributed stiffening plates 16 arranged at a certain interval between the two intermediate webs 13 in the disconnected area of ​​the lateral inner web 14 and the lateral outer web 15. The distributed stiffening plates 16 are perpendicular to the intermediate webs 13 and the intermediate flanges 11, and their edges are fixedly connected to the inner walls of the intermediate webs 13 and the intermediate flanges 11.

[0027] A connecting stiffening plate 17 is provided in the cavity of the cross-combined lower chord 1 at the corresponding connection position of each truss member. The connecting stiffening plate 17 is perpendicular to the inner wall of the cavity of the cross-combined lower chord 1 and is fixedly connected to the inner wall of the cavity of the cross-combined lower chord 1.

[0028] Furthermore, the cross-combined upper chord 2 and the cross-combined lower chord 1 are connected in the same manner.

[0029] The multi-layer truss cross diagonal web member 41 is fixedly connected at the upper end to the intersection of the cross combined upper chord 2 and the central straight web member 3, extends from the upper end of the central straight web member 3 along the direction of the multi-layer truss 4 to both sides, and is fixedly connected at the lower end to the intersection of the cross combined lower chord 1 and the multi-layer truss web member 42; the single-layer truss cross diagonal web member 51 is fixedly connected at the lower end to the intersection of the cross combined lower chord 1 and the central straight web member 3, extends from the lower end of the central straight web member 3 along the direction of the single-layer truss 5 to both sides, and is fixedly connected at the upper end to the intersection of the cross combined upper chord 2 and the single-layer truss web member 52; this achieves spatial staggered intersection of the multi-layer truss cross diagonal web member 41 and the single-layer truss cross diagonal web member 51, avoiding collisions between multiple members and ensuring a clear and non-concentrated load transfer path for the truss.

[0030] like Figure 2 , Figure 4 As shown, in order to ensure that the intersecting diagonal web members do not intersect in space, the cross section of the central straight web member needs to have sufficient width. The intersecting diagonal web members 41 of the multi-layer truss and the intersecting diagonal web members 51 of the single-layer truss are aligned with the outer side of the central straight web member 3 at the connection position with the central straight web member 3.

[0031] The lower chord 1 of the cross-combination is provided with chord connecting plates 18 on both sides of the center point where the multi-layer truss 4 and the single-layer truss 5 intersect. The chord connecting plates 18 are set along the direction of the lateral secondary truss 6 and are fixedly connected to the lower chord 1 of the cross-combination. The lateral secondary truss chord 61 is fixedly connected to the edge of the lateral flange plate of the lower chord 1 of the cross-combination and the chord connecting plate 18. The lateral secondary truss web member 62 is connected to the central straight web member 3 and the lateral flange plate of the lower chord 1 of the cross-combination.

[0032] The upper web member 43 of the multi-layer truss is located directly above the central straight web member 3 and is fixedly connected to the upper surface of the cross-combined upper chord member 2.

[0033] The diagonal web members of each truss are enlarged at both ends of the connection and fixing position to distribute the load and strengthen the connection.

[0034] A construction method for a large-span steel truss structure with different numbers of stories and small-angle cross-connection nodes, used for the construction of the aforementioned large-span steel truss structure with different numbers of stories and small-angle cross-connection nodes, includes the following steps: Step 1: Install the intermediate flange plate 11, an intermediate web plate 13, and the distribution stiffening plate 16 and connecting stiffening plate 17 between the intermediate web plates 13 of the cross-combined lower chord 1, and fully weld the stiffening plate to the intermediate flange plate 11. Then install another intermediate web plate 13 and fully weld all the contact surfaces of the plates.

[0035] Step 2: Install the inner lateral web 14 between the lateral flange plates 12 of the cross-combined lower chord 1. After welding and fixing, weld and fix the lateral flange plates 12 and the inner lateral web 14 to the intermediate web 13 at the connection position. Install the connecting stiffening plate 17 between the lateral flange plates 12 and weld and fix the connecting stiffening plate 17 to the lateral flange plates 12. Then install the outer lateral web 15. Install the chord connecting plate 18 on both sides of the center position of the cross-combined lower chord 1 and fully weld and fix all the contact surfaces of the plates.

[0036] Step 3: Install the cross-combination upper chord 2 in the same manner.

[0037] Step 4: Weld the lower end of the central straight web member 3 to the center of the upper surface of the cross-combined lower chord member 1, and weld the lower ends of the multi-layer truss web members 42 and the single-layer truss web members 52 to the upper surface of the cross-combined lower chord member 1 in sequence from left to right outwards.

[0038] Step 5: Install the cross-combined upper chord 2 directly above the cross-combined lower chord 1, and weld the upper end of the installed web member to the lower surface of the cross-combined upper chord 2 for fixation.

[0039] Step 6: Fix both ends of the multi-layer truss cross diagonal web member 41 to the intersection of the cross combination upper chord member 2 and the multi-layer truss web member 42, and the intersection of the cross combination lower chord member 1 and the central straight web member 3, respectively.

[0040] Step 7: Fix the two ends of the single-layer truss cross diagonal web member 51 to the intersection of the cross combination lower chord member 1 and the single-layer truss web member 52, and the intersection of the cross combination upper chord member 2 and the central straight web member 3, respectively.

[0041] Step 8: Fix the lower end of the upper web member 43 of the multi-layer truss to the upper surface of the cross-combined upper chord member 2.

[0042] Step 9: Fix the lateral secondary truss chord 61 to the chord connecting plate 18 and the lateral flange plate 12, and fix the lower end of the lateral secondary truss web member 62 to the intersection of the cross-combined lower chord 1 and the central straight web member 3.

[0043] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A connection structure of a super-long-span different-layer small-angle intersecting steel truss, for reliably connecting a small-angle intersecting multi-layer truss (4) and a single-layer truss (5), characterized by, It includes a cross-combined lower chord (1), a cross-combined upper chord (2), a central straight web member (3), a multi-layer truss cross-diagonal web member (41), a multi-layer truss web member (42), a single-layer truss cross-diagonal web member (51), and a single-layer truss web member (52). The central straight web member (3) serves as a shared straight web member for two trusses and is located at the center point where the multi-layer truss (4) and the single-layer truss (5) intersect. Its upper and lower ends are fixedly connected to the cross-combined upper chord (2) and the cross-combined lower chord (1), respectively. The cross-combined lower chord (1) has the same structure as the cross-combined upper chord (2). The cross-combined lower chord (1) is connected in the direction of the lower chord of the multi-layer truss (4). The lower chord of the single-layer truss (5) is broken at the intersection with the lower chord of the multi-layer truss (4) and is fixedly connected to the lower chord of the multi-layer truss (4) at the intersection edge. The flange plate of the cross-combined lower chord (1) is divided into an intermediate flange plate (11) along the chord direction of the multi-layer truss (4) and a lateral flange plate (12) along the chord direction of the single-layer truss (5). The lateral flange plate (12) extends beyond the lateral inner web plate (14) and lateral outer web plate (15) of the lower chord of the single-layer truss (5), extending inward to the side wall of the intermediate web plate (13) of the lower chord of the multi-layer truss (4) and fixedly connected to the side wall, and extending outward to the minimum width of the cross-combined lower chord (1) section is not less than the sum of the flange widths of the lower chord of the multi-layer truss (4) and the lower chord of the single-layer truss (5). The multi-layer truss cross diagonal web members (41) and the single-layer truss cross diagonal web members (51) are aligned with the outer side of the central straight web member (3) at the connection position with the central straight web member (3); The web of the multi-layer truss (4) in the chord direction is called the intermediate web (13), the web of the single-layer truss (5) that is close to the intermediate web (13) is called the inner lateral web (14), and the web that is far from the intermediate web (13) is called the outer lateral web (15). The intermediate web (13) extends upward and downward from the flange of the multi-layer truss (4) by a distance equal to the thickness of the intermediate web (13). A distribution stiffening plate (16) is provided between the two intermediate web plates (13) in the disconnected area of ​​the lateral inner web plate (14) and the lateral outer web plate (15). The distribution stiffening plate (16) is fixedly connected to the inner wall of the intermediate web plate (13) and the intermediate flange plate (11) perpendicular to it. The cavity of the cross-combination lower chord (1) is provided with connecting stiffening plates (17) at the corresponding member connection positions of each truss. The connecting stiffening plates (17) are perpendicular to the inner wall of the cavity of the cross-combination lower chord (1) and are fixedly connected to the inner wall of the cavity of the cross-combination lower chord (1).

2. The small-angle intersecting steel truss connection structure with different numbers of layers across an ultra-large span as described in claim 1, characterized in that, The upper end of the cross diagonal web member (41) of the multi-layer truss is fixedly connected to the intersection of the cross combination upper chord member (2) and the central straight web member (3), and extends from the upper end of the central straight web member (3) along the direction of the multi-layer truss (4) to both sides, and the lower end is fixedly connected to the intersection of the cross combination lower chord member (1) and the multi-layer truss web member (42). The lower end of the single-layer truss cross diagonal web member (51) is fixedly connected to the intersection of the cross combination lower chord (1) and the central straight web member (3), and extends from the lower end of the central straight web member (3) along the direction of the single-layer truss (5) to both sides, and the upper end is fixedly connected to the intersection of the cross combination upper chord (2) and the single-layer truss web member (52).

3. The small-angle intersecting steel truss connection structure with different numbers of layers across an ultra-large span as described in claim 1, characterized in that, The cross-sectional width of the central straight web member (3) is increased. The multi-layer truss cross diagonal web members (41) and the single-layer truss cross diagonal web members (51) are aligned with the outer side of the central straight web member (3) at the connection position with the central straight web member (3).

4. The small-angle intersecting steel truss connection structure with different numbers of layers across an ultra-large span as described in claim 1, characterized in that, Lateral secondary trusses (6) are connected on both sides of the main truss formed by connecting the multi-layer truss (4) and the single-layer truss (5). The lateral secondary trusses (6) are fixedly connected at the intersection of the cross-combined chord and the central straight web member (3) of the main truss.

5. The small-angle intersecting steel truss connection structure with different numbers of layers across an ultra-large span as described in claim 4, characterized in that, The lateral secondary truss (6) includes lateral secondary truss (6) chords and lateral secondary truss (6) web members. The cross-combined lower chord (1) is provided with chord connecting plates (18) on both sides of the center point where the multi-layer truss (4) and the single-layer truss (5) intersect. The chord connecting plates (18) are arranged along the lateral secondary truss (6) direction and are fixedly connected to the cross-combined lower chord (1). The lateral secondary truss (6) chords are fixedly connected to the edge of the lateral flange plate (12) and the chord connecting plates (18).

6. The small-angle intersecting steel truss connection structure with different numbers of layers across an ultra-large span as described in claim 1, characterized in that, The diagonal web members of each truss are enlarged at both ends when they are connected and fixed.

7. A construction method for implementing the small-angle intersecting steel truss connection structure with different numbers of layers and a large span as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Install the middle flange plate (11) and a middle web plate (13) of the cross-combined lower chord (1), install the distribution stiffening plate (16) and the connecting stiffening plate (17) between the middle flange plates (11), and weld the distribution stiffening plate (16) and the connecting stiffening plate (17) to the middle flange plate (11) respectively. Then install another middle web plate (13). Step 2: Install the inner lateral web plate (14) between the lateral flange plates (12), and weld it in place. Then weld the lateral flange plates (12) and the inner lateral web plate (14) to the intermediate web plate (13) at the connection position. Install the connecting stiffening plate (17) between the lateral flange plates (12), and weld the connecting stiffening plate (17) to the lateral flange plates (12). Then install the outer lateral web plate (15). Step 3: Install the cross-combined upper chord (2) in the same manner; Step 4: Weld the lower end of the central straight web member (3) to the center position of the upper surface of the cross-combined lower chord member (1), and weld the lower ends of the multi-layer truss web members (42) and the single-layer truss web members (52) to the upper surface of the cross-combined lower chord member (1) from left to right outwards. Step 5: Install the cross-combined upper chord (2) directly above the cross-combined lower chord (1), and weld the upper ends of the installed central straight web member (3), multi-layer truss web member (42) and single-layer truss web member (52) to the lower surface of the cross-combined upper chord (2) for fixation. Step 6: Fix the two ends of the multi-layer truss cross diagonal web member (41) to the intersection of the cross combination upper chord member (2) and the multi-layer truss web member (42), and the intersection of the cross combination lower chord member (1) and the central straight web member (3), respectively. Step 7: Fix the two ends of the single-layer truss cross diagonal web member (51) to the intersection of the cross combination lower chord member (1) and the single-layer truss web member (52), and the intersection of the cross combination upper chord member (2) and the central straight web member (3), respectively.

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