Orthogonal prestressed reinforced concrete space vierendeel truss single-layer roof structure and construction method
By using orthogonal prestressed reinforced concrete hollow truss structures, the problems of easy corrosion and low safety in large-span spatial buildings are solved, and efficient and economical electromechanical pipeline layout and net height increase are achieved. It is suitable for buildings in heavy-load and humid environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 中南建筑设计院股份有限公司
- Filing Date
- 2026-01-27
- Publication Date
- 2026-04-17
AI Technical Summary
In large-span single-story buildings, especially in humid environments, existing technologies are prone to corrosion and have low safety, and are difficult to meet the requirements for the layout of electromechanical pipelines. Conventional prestressed concrete structures have low safety when opening large openings, and reinforced concrete/steel trusses have poor applicability.
It adopts an orthogonal prestressed reinforced concrete spatial open truss structure, including transverse and longitudinal open trusses, vertical bracing and roof panels, forming a regular spatial grid. The open cavities are used for electromechanical pipelines, the prestressed tendons are balanced under stress, the component size is adjustable, and the construction is simple.
It achieves an efficient and safe layout of electromechanical utility tunnels, increases building height, reduces structural weight, lowers construction costs, is suitable for buildings with heavy loads and high height requirements, and has good durability.
Smart Images
Figure CN121875414A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to large-span spatial buildings, and more particularly to columns-free large spaces, buildings with heavy loads on floors / roofs and mechanical and electrical pipes, and high requirements for interior clear height, as well as construction methods. Background Technology
[0002] Cultural and sports-related public buildings require a column-free, large-space architectural effect due to functional needs. Currently, common structural systems include spatial steel trusses, steel space frames, steel space shells, cable-membrane structures, steel-concrete composite structures, and reinforced concrete truss structures. However, in some large-span single-story buildings with special requirements, such as single-story buildings with heavy floor / roof loads, mechanical and electrical pipelines, high indoor clear height requirements, and high structural durability requirements, the above-mentioned structures cannot form a compact floor structure that can accommodate mechanical and electrical pipeline spaces due to the inherent limitations of their own systems.
[0003] Especially in applications in damp spaces, such as large swimming pools, traditional steel space frames and spatial steel trusses cannot be used due to their susceptibility to corrosion. On the other hand, conventional prestressed concrete structures have relatively low safety due to their large spans and large openings for electromechanical structures to pass through.
[0004] The double-layer composite floor slab supporting truss structure has a drawback. The reinforced concrete truss structure forms a two-layer floor structure through the upper and lower chord layers. The upper and lower chord layers need to be connected by columns to form a high mezzanine space, which is wasteful to use as space for the electromechanical pipe gallery. Furthermore, the composite floor slab with the lower chord layer forms two separate spaces, which is not conducive to the laying and maintenance of the electromechanical pipe gallery. Summary of the Invention
[0005] The technical problem to be solved by this invention is to provide an orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure and construction method. This not only efficiently solves the design problems of low safety of large openings in conventional prestressed concrete structures, poor applicability of reinforced / steel-concrete trusses, and poor corrosion and durability of spatial steel structures, but also enables the low-cost manufacture of electromechanical pipe gallery spaces to meet indoor clear height requirements, resulting in significant economic benefits.
[0006] This invention is particularly suitable for buildings with large, column-free spaces, heavy loads on floors / roofs, and requirements for mechanical and electrical pipes, as well as high requirements for interior clear height. It is especially suitable for large-span space buildings with special needs, such as buildings that are in a humid environment for a long time and have high durability requirements.
[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A single-story roof structure with orthogonal prestressed reinforced concrete spatial open truss, comprising: A transverse open-web truss consists of an upper chord, a lower chord, vertical web members, and at least straight prestressed tendons within the lower chord. The longitudinal open truss includes an upper chord and a lower chord, and is arranged orthogonally to the transverse open truss and shares the same vertical web member to form a regular spatial grid; the perimeter frame columns and edge trusses are used to connect the ends of the transverse open truss and the longitudinal open truss to form an integral spatial grid. The roof panel is integrally connected to the upper chord of the transverse open truss and the longitudinal open truss; The vertical web members enclose the space between the horizontal upper and lower chords and between the vertical upper and lower chords to form a through-hole, which is used to accommodate electromechanical pipelines and keep the roof panel forming a single-layer floor without interlayer space.
[0008] In the above technical solution, the transverse open trusses on both sides are symmetrically arranged; the transverse open trusses on each side are arranged diagonally at the lower end and the upper end, or the transverse open trusses on each side are arranged horizontally.
[0009] In the above technical solution, each transverse open truss and longitudinal open truss are arranged orthogonally in the horizontal projection plane.
[0010] In the above technical solution, the transverse open truss is the main load-bearing component, and the longitudinal open truss is an out-of-plane stabilizing component.
[0011] In the above technical solution, the lower chord of the transverse hollow truss is subjected to transverse compression through the self-balancing effect of the straight prestressed tendons.
[0012] In the above technical solution, the span of the transverse open truss is smaller than the span of the longitudinal open truss, and the ratio of the longitudinal to the transverse span is greater than or equal to 2, so that the roof forms a unidirectional force transmission and out-of-plane stable force mode.
[0013] In the above technical solution, the area on the lower surface of the roof panel without trusses, together with the hollow opening, constitutes the electromechanical installation space.
[0014] In the above technical solution, the height of the upper and lower chord sections of the longitudinal open truss is the same as that of the upper and lower chord sections of the transverse open truss, and the width of the upper and lower chord sections of the longitudinal truss is smaller than that of the upper and lower chord sections of the transverse truss. This design aims to reduce the structural self-weight.
[0015] In the above technical solution, the net dimensions of the hollow cavity are not less than the outer contour dimensions of the electromechanical pipeline in both the transverse and longitudinal directions, and the cavity opening is surrounded by haunch reinforcement bars to meet the shear and crack resistance requirements of the large opening.
[0016] In the above technical solution, when the upper chord is equipped with straight prestressing tendons, the length of the straight prestressing tendons in the lower chord is much greater than the length of the straight prestressing tendons in the upper chord. In the above technical solution, the prestressed tendons are arranged in a straight line along 50%-80% of the total length of the lower chord of the transverse open truss at the middle section of the overall lower chord length, and are simultaneously tensioned and anchored at both ends.
[0017] In the above technical solution, the prestressing tendon is a bonded steel strand.
[0018] In the above technical solution, the transverse open truss, longitudinal open truss, vertical bracing and roof panel are all cast-in-place reinforced concrete, forming a continuous spatial integral force-bearing system.
[0019] In the above technical solution, the vertical web members are assembled into an I-shaped three-dimensional support structure by combining templates and then cast.
[0020] Based on the above, the present invention also provides: A construction method for an orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure. Includes the following steps: After the perimeter frame columns and edge trusses are constructed, straight prestressed tendons are pre-embedded in the lower chord of the transverse open truss, and cast in place simultaneously along the transverse and longitudinal orthogonal directions to form the lower chord of the transverse open truss and the lower chord of the longitudinal open truss. Then, the vertical web member combination template is set up and cast in place to form the vertical web members. The horizontal open web truss and the longitudinal open web truss vertical web member frame share the vertical web members and form a through-hole between the upper and lower chords. The upper chord of the transverse open truss, the upper chord of the longitudinal open truss, and the roof panel are simultaneously cast in place along the orthogonal directions of the transverse and longitudinal directions. After the overall concrete reaches the design strength, the vertical web member combination formwork is dismantled, and the prestressed tendons are tensioned to balance the axial tension of the lower chord, thereby maintaining the roof as a single-layer structure.
[0021] In the above technical solution, after the tensioning step is completed, the hollow cavity serves as a channel for electromechanical pipelines, and the exposed structure effect can be formed on the lower surface of the roof without the need for a suspended ceiling.
[0022] In summary, this invention discloses an orthogonally arranged prestressed reinforced concrete spatial open truss structure and its construction method, which is applicable to buildings with column-free large spaces, heavy loads on floors / roofs, and requirements for mechanical and electrical pipelines, as well as high requirements for indoor clear height. It is especially suitable for large-span space buildings with special needs, such as swimming pools that are in a humid environment for a long time.
[0023] This invention provides a safe and reliable structural system option for this type of building. This structural system efficiently solves the design challenges of low safety in conventional prestressed concrete structures with large openings, poor applicability of reinforced concrete / steel-concrete trusses, and poor durability of spatial steel structures under relatively harsh environmental conditions. This invention features a clear force transmission path, good structural load-bearing capacity and overall stiffness, and the component dimensions and arrangement can be adjusted according to actual engineering needs, achieving both aesthetic appeal and functional requirements for mechanical and electrical piping passage, while also ensuring structural safety, reliability, and significant economic benefits.
[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The component size and component arrangement of this structural system adopt an orthogonal placement method, which is easy to construct and can be adjusted according to actual engineering needs, combining safety, applicability and economy.
[0025] (2) The components of this structural system are of regular size, and the structure is beautiful and grand. The structure is fully exposed without the need for a suspended ceiling, which not only saves costs but also achieves a good effect of showcasing the tension of a large-span building.
[0026] (3) This structural system is a fully hollow structure with uniform spacing between vertical web members. The floor is essentially a single-layer floor. Equipment pipes can pass through the openings between the upper and lower chords, maximizing the building's net height, avoiding the waste of space in the composite double-layer floor, and facilitating pipe maintenance.
[0027] (4) The upper and lower chord sections of this structural system are uniform, the prestressed steel bars are arranged regularly, the connection is simple, the construction is convenient, and the construction quality is easy to control.
[0028] (5) The vertical web members of this invention are formed by casting in place using a three-dimensional combined formwork and then demolding. The use of hollow openings reduces the self-weight of the floor slab while also meeting the high single-story clearance requirements of the floor slab and the personalized needs of the mechanical and electrical pipe gallery layout. At the same time, the shared vertical web member structure in both the horizontal and vertical directions reduces manufacturing and construction costs.
[0029] (6) This structural system has both excellent load-bearing capacity and seismic performance, and is well-suited for heavy load requirements and high seismic intensity areas. The top of the single-story floor can be used for outdoor space load-bearing requirements when needed, such as the aerial activity space in gymnasiums or school campuses. Attached Figure Description
[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is an overall schematic diagram of an orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to an embodiment of the present invention.
[0031] Figure 2This is a schematic diagram of a single transverse open truss according to an embodiment of the present invention.
[0032] Figure 3 This is a schematic diagram of the structure of a single transverse open truss after applying prestressed steel bars according to an embodiment of the present invention.
[0033] Figure 4 This is a schematic diagram of the overall structure of a single transverse open truss according to an embodiment of the present invention.
[0034] Figure 5 This is a schematic diagram of the overall structure (including the basement area) applied to a single transverse open truss according to an embodiment of the present invention.
[0035] Figure 6 This is a schematic diagram of the lower chord planar arrangement of a single-layer roof of an orthogonal prestressed reinforced concrete spatial open truss according to an embodiment of the present invention.
[0036] Figure 7 This is a schematic diagram of the upper chord planar arrangement of a single-layer roof of an orthogonal prestressed reinforced concrete spatial open truss according to an embodiment of the present invention.
[0037] Figure 8 This is a schematic diagram of the orthogonal prestressed reinforced concrete spatial open truss single-layer roof vertical web member combined formwork structure according to an embodiment of the present invention (the left side is the combined structure, and the right side is the disassembled formwork structure).
[0038] Figure 9 This is a schematic diagram of the orthogonal, upright, prestressed reinforced concrete spatial truss single-layer roof vertical web member combined formwork assembly state (before cast-in-place).
[0039] Figure 10 yes Figure 9 A schematic diagram of the lateral structure (before casting).
[0040] Figure 11 This is a schematic diagram of the overall electromechanical installation according to an embodiment of the present invention.
[0041] Figure 12 This is a schematic diagram of the electromechanical installation structure of the transverse open truss according to an embodiment of the present invention.
[0042] Figure 13 This is a simplified flowchart of the construction method for the orthogonal prestressed reinforced concrete spatial hollow truss single-layer roof structure of the present invention. Detailed Implementation
[0043] 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.
[0044] like Figure 1-7 As shown, the orthogonal prestressed reinforced concrete spatial open-web truss single-layer roof structure system proposed according to the present invention mainly consists of transverse open-web trusses 100, longitudinal open-web trusses 200, perimeter frame columns 300, perimeter edge sealing trusses 400, floor / roof panels 500, and other components. The transverse open-web truss 100 is a short-span truss, composed of four parts: a transverse upper chord 102, a transverse lower chord 101, vertical web members 103, and lower chord prestressing tendons 104. The longitudinal open-web truss 200 is a long-span truss, sharing the vertical web member 103 with the transverse open-web truss 100. Its upper chord 201 and lower chord 202 mainly serve as out-of-plane horizontal supports for the transverse open-web truss.
[0045] If necessary, the upper chord prestressing tendon 105 can be provided, and the lower chord prestressing tendon 104 can be much larger than the upper chord prestressing tendon 105. Moreover, the two should preferably be staggered and not overlap along the main transverse direction of the transverse open truss.
[0046] The transverse open truss 100 is the main load-bearing direction, and its transverse upper chord 102 and transverse lower chord 101 have the same cross section; the longitudinal open truss 200 is the secondary load-bearing direction. In order to reduce the self-weight of the structure, the height of its upper chord 201 and lower chord 202 is the same as that of the transverse open truss chord, but its width is only half the width of the transverse open truss chord.
[0047] The net size of the opening formed by the transverse upper chord 102, transverse lower chord 101 and adjacent vertical web members 103 of the transverse open truss is 1600mm×1700mm. Large HVAC pipes can pass through this opening, and the mechanical and electrical pipelines can be arranged freely and are easy to adjust later, with good functionality.
[0048] The transverse open truss spans 100mm are set according to regulations. The net dimensions of the openings in the middle section are basically the same, while the net dimensions of the openings at both ends can be slightly smaller or consistent with those in the middle section. During construction, the full-span truss structure is arranged according to the number of openings as follows: Figure 5 As shown.
[0049] The transverse open truss 100 is set at a certain angle between the high and low ends. The perimeter frame column 300 at the low end is set vertically, and the perimeter frame column 300 at the high end is supported diagonally outward along the vertical direction.
[0050] The perimeter frame columns are 300mm high and are set on the foundation. When the foundation is a 600mm basement space, support and reinforcement are required.
[0051] The structural system proposed in this invention features regular arrangement and well-organized members, eliminating the need for suspended ceilings and allowing the structure to be fully exposed, showcasing the structural tension effect of large-span buildings.
[0052] In the preferred embodiment: the longitudinal open truss 200 has a span of 67.2m, the transverse open truss 100 has a span of 33.6m, and the longitudinal to transverse span ratio is 2:1, which is a typical unidirectional load-bearing structural system; the center distance between the upper and lower chords of the transverse and longitudinal open trusses is 2.4m, and the center distance between adjacent vertical web members 103 is 2.1m; the cross sections of the upper and lower chords of the transverse open truss are both 500×700, the cross sections of the vertical web members in the middle section are 500×500, and the cross sections of the vertical web members in the two end sections are 700×500; the cross sections of the upper and lower chords of the longitudinal open truss are both 250×700.
[0053] Limitations between component proportions: The center distance between the upper and lower chords of the transverse and longitudinal open trusses can be determined according to the span of the transverse open truss and the load it bears. For heavy-duty floors or roofs, the center distance between the upper and lower chords of the transverse open trusses can be taken as 1 / 12 to 1 / 16 of its span.
[0054] Preferably, the center distance between adjacent vertical web members should not be too large, and can generally be 0.8 to 1.0 times the center distance between the upper and lower chords of the transverse open web truss.
[0055] Preferably, the upper and lower chord sections of the transverse open truss can be determined by the maximum axial tensile force borne by the lower chord, the height of the upper and lower chords of the longitudinal open truss is the same as the height of the upper and lower chords of the transverse open truss, and the width can be half the width of the upper and lower chords of the transverse open truss.
[0056] Preferably, the amount of linear prestress in the lower chord of the transverse open truss can be determined as 0.8 to 1.0 times the maximum axial tensile force of the lower chord of the transverse open truss under balanced dead load conditions.
[0057] The proposed system has been successfully applied to practical engineering. It is more applicable when the ratio of the span of the longitudinal open truss to that of the transverse open truss is less than 2, and the center distance between the upper and lower chords of the transverse and longitudinal open trusses can be further reduced. It can also be extended to orthogonal oblique prestressed reinforced concrete spatial open truss structures or oblique oblique prestressed concrete spatial open truss structures.
[0058] The cast-in-place forming process of vertical web members 103 requires the following vertical web member assembly formwork: Figures 8-10 As shown, the combined formwork uses wooden molds and is composed of 7 parts (main formwork 1032, first lateral formwork 1033, second lateral formwork 1034, and vertical formwork 1035). The beam side formwork or main formwork 1032 is fixed with square steel pipes 1031, the vertical formwork 1035 in the beam is fixed with two tie rods 1039, the first lateral formwork 1033 and the second lateral formwork 1034 are fixed with round steel pipes 1036, and the vertical formwork 1035 is fixed with round steel pipes 1037. The combined formwork is connected to the wooden beams 1038 with nails.
[0059] The area on the underside of the roof panel without trusses creates a flat visual effect. This area, together with the openwork, forms the mechanical and electrical installation space. Furthermore, no suspended ceiling is required below this space. Figure 11 and Figure 12 As shown, the air duct 700 and water pipe 800 pass through the openings of the hollow trusses 100 in each of the transverse hollow trusses and are laid longitudinally in the space above the roof.
[0060] The clearance created by the hollow cavity allows for the effective arrangement of equipment and pipelines, which not only improves the clearance but also achieves a good interior effect.
[0061] For heavy-duty floor or roof trusses, the center distance between the upper and lower chords can be taken as 1 / 12 to 1 / 16 of the span. In this example, the clear height difference between the upper chord 102 and the lower chord 101 of the transverse open truss 100 is preferably 1.7m (which is also the height difference of the opening space).
[0062] Therefore, after implementing the above methods, the orthogonal prestressed reinforced concrete open-web truss roof structure is well-suited for single-story buildings, with the following advantages: 1. The upper chord is under compression, the lower chord is under tension, and the straight web member is under shear. The spatial force is fully utilized by levering the lever arm between the upper and lower chords. 2. By applying linear prestressing to balance the large axial tension at mid-span of the lower chord, the cross-sectional dimensions of the components can be controlled to be relatively small, resulting in a light and airy architectural effect. 3. Swimming pool buildings are often located in humid environments, and prestressed structures can effectively improve their durability. 4. The pipeline layout of swimming pool buildings is relatively complex. The equipment pipelines can be effectively arranged by using the clearance between the upper and lower chords of the hollow truss, which not only improves the clearance but also achieves a good indoor air-support effect.
[0063] Example 2: Based on Example 1, this embodiment, for example Figure 13 As shown, the construction method according to the present invention is carried out in the following order: After the perimeter frame columns and edge trusses are constructed, straight prestressed tendons are pre-embedded in the lower chord of the transverse open truss, and cast in place simultaneously along the transverse and longitudinal orthogonal directions to form the lower chord of the transverse open truss and the lower chord of the longitudinal open truss. Then, the vertical web member combination template is set up and cast in place to form the vertical web members. The horizontal open web truss and the longitudinal open web truss vertical web member frame share the vertical web members and form a through-hole between the upper and lower chords. Straight prestressing tendons are pre-embedded in the upper chord of the transverse open truss, and the upper chord of the transverse open truss, the upper chord of the longitudinal open truss, and the roof panel are simultaneously cast in place along the orthogonal directions of transverse and longitudinal directions. After the overall concrete reaches the design strength, the vertical web member combination formwork is dismantled, and the prestressed tendons are tensioned to balance the axial tension of the lower chord, thereby maintaining the roof as a single-layer structure.
[0064] That is: Erecting high-support full-span scaffolding → Laying the bottom formwork of the lower chord → Tying the lower chord beam reinforcement → Installing the beam side formwork → Constructing the haunch reinforcement and web reinforcement → Pouring the lower chord concrete → Installing the combined formwork of vertical web members for the open opening → Installing the beam side formwork → Laying the slab formwork → Tying the upper chord and diagonal web reinforcement → Tying the slab reinforcement → Pouring the upper chord beam and slab concrete → Curing → Tensioning the prestressing after the concrete reaches the design strength.
[0065] The height of the scaffolding is 8m to 14.7m, the spacing between uprights is 0.9m, the step distance is 1.5m, and the high formwork support system is erected according to the high formwork scheme.
[0066] After the tensioning process is completed, the hollow cavity serves as a channel for electromechanical pipelines, and the exposed structure effect can be achieved without installing a suspended ceiling on the lower surface of the roof.
[0067] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
Claims
1. A single-story roof structure with orthogonal prestressed reinforced concrete spatial open truss, characterized in that... include: A transverse open-web truss consists of an upper chord, a lower chord, vertical web members, and at least straight prestressed tendons within the lower chord. The longitudinal open truss includes an upper chord and a lower chord, and is arranged orthogonally to the transverse open truss and shares the same vertical web member, forming a regular spatial grid; Perimeter frame columns and edge sealing trusses are used to connect the ends of transverse open trusses and longitudinal open trusses; The roof panel is integrally connected to the upper chord of the transverse open truss and the longitudinal open truss; The vertical web members enclose the space between the horizontal upper and lower chords and between the vertical upper and lower chords to form a through-hole, which is used to accommodate electromechanical pipelines and keep the roof panel forming a single-layer floor without interlayer space.
2. The orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to claim 1, characterized in that... The transverse open trusses and the longitudinal open trusses are arranged orthogonally in the horizontal projection plane.
3. The orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to claim 1, characterized in that... The lower chord of the transverse open truss is subjected to transverse compression through the self-balancing effect of the straight prestressed tendons.
4. The orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to claim 1, characterized in that... The span of the transverse open truss is smaller than the span of the longitudinal open truss, and the ratio of the longitudinal to the transverse span is greater than or equal to 2, so that the roof forms a unidirectional force transmission and out-of-plane stable force mode.
5. The orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to claim 1, characterized in that... The area on the underside of the roof panel without trusses, together with the open space, forms the electromechanical installation space.
6. The orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to claim 1, characterized in that... The height of the upper and lower chord sections of the longitudinal open truss is the same as that of the upper and lower chord sections of the transverse open truss.
7. The orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to claim 1, characterized in that... The cross-sectional width of the upper and lower chords of the longitudinal truss is smaller than that of the upper and lower chords of the transverse truss.
8. The orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to claim 1, characterized in that... When the upper chord is equipped with straight prestressing tendons, the length of the straight prestressing tendons in the lower chord is much greater than the length of the straight prestressing tendons in the upper chord.
9. The orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure according to claim 1, characterized in that... The transverse open trusses, longitudinal open trusses, vertical braces, and roof panels are all cast-in-place reinforced concrete, forming a continuous spatial integral force-bearing system.
10. A construction method for an orthogonal prestressed reinforced concrete spatial open truss single-layer roof structure, characterized in that... Includes the following steps: After the perimeter frame columns and edge trusses are constructed, straight prestressed tendons are pre-embedded in the lower chord of the transverse open truss, and cast in place simultaneously along the transverse and longitudinal orthogonal directions to form the lower chord of the transverse open truss and the lower chord of the longitudinal open truss. Then, the vertical web member combination template is set up and cast in place to form the vertical web members. The horizontal open web truss and the longitudinal open web truss vertical web member frame share the vertical web members and form a through-hole between the upper and lower chords. The upper chord of the transverse open truss, the upper chord of the longitudinal open truss, and the roof panel are simultaneously cast in place along the orthogonal directions of the transverse and longitudinal directions. After the overall concrete reaches the design strength, the vertical web member combination formwork is dismantled, and the prestressed tendons are tensioned to balance the axial tension of the lower chord, thereby maintaining the roof as a single-layer structure.