A large-span prestressed concrete open-hole beam frame structure system reinforced by section steel
By using steel reinforcement in large-span prestressed concrete beam-beam frame structures with openings, combined with prestressed concrete and inclined reinforcement at the openings, the problems of stress concentration and strength weakening caused by openings on the beams were solved, improving construction quality and seismic performance, and reducing project costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI TONGJI CONSTR ENG DESIGN CO LTD
- Filing Date
- 2023-12-19
- Publication Date
- 2026-07-31
AI Technical Summary
In large-span prestressed concrete open beam frame structures, openings in the beams cause stress concentration, weakened strength and stiffness, affecting the beams' durability and shear bearing capacity, and also result in low construction efficiency.
The method of steel reinforcement is adopted. By setting steel-concrete structures on the upper and lower chords of the opening, combined with prestressed concrete and diagonal reinforcement at the opening, an integral connection is formed, which reduces the amount of steel reinforcement and improves construction quality and seismic performance.
It improves the seismic performance of large-span prestressed concrete open beam frame structures, reduces the amount of steel reinforcement, increases construction efficiency, lowers project costs, increases usable space, and reduces carbon emissions.
Smart Images
Figure CN224578889U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of construction technology of large-span prestressed concrete open beam frame structure system, and more specifically, to a large-span prestressed concrete open beam frame structure system reinforced with steel profiles. Background Technology
[0002] In recent years, side-platform railway passenger stations have been widely used in the design of small and medium-sized high-speed railway passenger stations due to their economic efficiency and architectural characteristics. However, due to investment control and functional constraints, two-story side-platform passenger station buildings typically employ traditional single-span, large-span reinforced concrete frame structures. The ceiling height of the first floor is controlled at around 5.4 meters, resulting in a relatively cramped waiting hall and impacting passenger comfort. To meet the requirements of passenger comfort, clearance, and cost reduction, a large-span prestressed concrete open beam frame structure scheme is proposed. This facilitates the passage of equipment pipelines and increases the building's clearance. If equipment pipelines pass through openings in the beams, the number of building floors and the volume ratio can be increased without changing the total height, reducing carbon emissions and yielding significant social and economic benefits. Furthermore, when the number of building floors is fixed, this measure reduces the floor height, correspondingly decreasing the total building height, relatively increasing usable space, reducing weight, and mitigating load effects (including seismic and wind load effects), thereby reducing project costs.
[0003] However, openings in beams disrupt their integrity and continuity, easily leading to stress concentration at the corners of the openings and causing premature cracking. Excessive crack width can compromise beam durability. The presence of openings in the beam web weakens its strength and stiffness, altering its stress mechanism under static and seismic loads. Simultaneously, the shear capacity of beams with openings decreases significantly, while deflection increases markedly, particularly pronounced in large-span prestressed concrete frame structures.
[0004] Steel-concrete composite (SRC) structures are a type of composite structure that incorporates steel sections within a regular reinforced concrete structure. Compared to regular reinforced concrete structures, SRC structures have a higher upper limit for the total reinforcement (including both regular and structural steel) for the same cross-section, resulting in higher load-bearing capacity and stiffness. Compared to steel structures, SRC structures offer higher stiffness, better durability, and fire resistance, while also saving significant costs in terms of steel usage and corrosion and fire protection. Currently, SRC columns are widely used in general multi-story and high-rise building structures, while SRC beams are primarily used in large-span, heavy-load structures such as industrial plants, large stadiums, exhibition halls, bridges, and transfer structures in high-rise buildings.
[0005] Applying steel-concrete composite sections to the upper and lower chords of openings can compensate for the reduction in strength and stiffness caused by the openings, while also saving on steel reinforcement, avoiding steel congestion, and improving construction quality. Therefore, applying steel-concrete composite sections to openings becomes a viable option. By reinforcing openings in large-span prestressed concrete open beam frame structures with steel sections, a design method is provided for further promoting the application of large-span prestressed concrete open beam frame structures in areas with different seismic resistance levels. This reduces load effects (including seismic load effects and wind load effects), thereby lowering project costs and achieving significant economic and social benefits. Utility Model Content
[0006] The purpose of this invention is to address the shortcomings of existing technologies and, by leveraging the superior performance of steel-concrete composite structures, propose a large-span prestressed concrete open beam frame structure system reinforced with steel profiles. This system combines three traditional structural elements: steel-concrete composite, prestressed concrete, and diagonal reinforcement at the opening, thereby improving the seismic performance of the large-span prestressed concrete open beam frame structure.
[0007] The advantages of this utility model are mainly reflected in three aspects: steel-concrete composite structure, prestressed concrete, and reinforcement of the opening with inclined bars. In terms of component load transfer, the upper and lower chords of the opening are integrated with the adjacent concrete beams through steel-concrete composite, thereby improving the seismic performance of the overall frame structure. Regarding the amount of steel reinforcement, the reinforcement in the upper and lower chords of the opening is significantly reduced, thus greatly saving the fabrication time of precast components and on-site installation time, and improving construction quality. Therefore, the steel-reinforced large-span prestressed concrete open beam frame structure system proposed in this utility model conforms to my country's green development strategy for building industrialization.
[0008] The technical problem solved by this utility model can be achieved by the following technical solution:
[0009] A large-span prestressed concrete beam-frame structure system reinforced with steel profiles includes prestressed concrete beams, prestressed tendons, ordinary continuous steel bars, steel profiles for reinforcing the openings, stirrups for the upper and lower chords of the openings, corner bars for the upper and lower chords of the openings, reinforcing stirrups on the sides of the openings, and reinforcing diagonal bars on the sides of the openings.
[0010] The concrete beam contains prestressed tendons, ordinary continuous steel bars, steel sections for reinforcing the upper and lower chords of the opening, stirrups for the upper and lower chords of the opening, corner bars for the upper and lower chords of the opening, reinforcing stirrups on the sides of the opening, and reinforcing diagonal bars on the sides of the opening.
[0011] The steel section is located at the geometric center of the upper and lower chords of the opening, and its two ends are anchored in the adjacent intact concrete beam.
[0012] The steel section is fixed by the upper and lower chord stirrups of the opening, the upper and lower chord corner bars of the opening, and the reinforcing diagonal bars on the side of the opening.
[0013] The upper and lower chord reinforcement bars of the opening extend out of the opening area and are directly anchored to the adjacent complete concrete beam.
[0014] The reinforcing diagonal ribs on the side of the opening are bent in the area on the side of the opening via the upper and lower chords of the opening.
[0015] The prestressed concrete beam also includes a fully precast prestressed concrete beam; the bonded prestressing tendons include straight, broken, and curved prestressing tendons.
[0016] The bonded prestressed tendons within the opening area can be bonded, bonded, partially bonded, unbonded, or unbonded.
[0017] The prestressed tendons are constructed using a post-tensioning method.
[0018] Before reinforcing the steel-concrete composite beam, prestressed concrete beam, and inclined reinforcement at the opening, construction calculations were performed according to the force transmission mode suitable for ordinary concrete beams. After pouring the concrete beam and the upper and lower chords of the opening, once the concrete strength of the concrete beam and the upper and lower chords of the opening reached the design requirements, the bonded prestressed tendons were tensioned. After tensioning, construction stage calculations were performed according to unbonded frame beams. Under normal serviceability limit state, calculations were performed based on effective prestress. Under ultimate bearing limit state, the stress increment of the unbonded tendons was considered. Under seismic loads, the recovery performance provided by the unbonded tendons was considered.
[0019] Furthermore, the steel-reinforced large-span prestressed concrete open beam frame structure system consists of three traditional structures: steel-concrete composite structure, prestressed concrete structure, and opening diagonal reinforcement structure system.
[0020] Furthermore, the reinforcing bars of ordinary reinforced concrete beams (excluding opening areas) are tied according to the construction drawings. Stirrups are divided into dense and non-dense zones, and the reinforcement arrangement is based on design requirements.
[0021] Furthermore, the reinforcing stirrups on the sides of the opening, the corner bars of the upper and lower chords of the opening, and the stirrups of the upper and lower chords of the opening are tied in the corresponding positions. The reinforcement design is verified according to the relevant specifications.
[0022] Furthermore, the steel profiles are placed in the upper and lower chords of the opening, and fixed by the stirrups of the upper and lower chords, the corner bars of the upper and lower chords, and the reinforcing diagonal bars on the sides of the opening.
[0023] Furthermore, the prestressed tendons are placed inside the concrete beam member, pass through the lower chord of the opening and extend beyond the concrete beam at both ends, with clamps and anchors fixed at both ends respectively.
[0024] Furthermore, when pouring concrete, pay special attention to vibration in the opening area.
[0025] A large-span prestressed concrete open beam frame structure system reinforced with steel profiles includes the following steps:
[0026] Step 1: Tie the reinforcing cages for concrete columns and beams (excluding the opening area); the upper and lower chord stirrups, the stirrups on the sides of the opening, and the reinforcing diagonal bars on the sides of the opening should be placed in the opening area in advance.
[0027] Step 2: Tie the stirrups on the side of the opening.
[0028] Step 3: Place the steel section at the geometric center of the upper and lower chords of the opening and temporarily fix it.
[0029] Step 4: Insert the reinforcing diagonal bars on the side of the opening and the corner bars of the upper and lower chords of the opening into the stirrups of the upper and lower chords of the opening.
[0030] Step 5: Tie the reinforcing diagonal bars on the side of the opening, and place the corner bars and stirrups of the upper and lower chords of the opening in the corresponding positions.
[0031] Step 6: Adjust the position of each steel bar by fixing the position of the steel section through the upper and lower chords of the opening, the stirrups of the upper and lower chords of the opening, the corner bars of the upper and lower chords of the opening, and the reinforcing diagonal bars on the sides of the opening.
[0032] Step 7: Pass the prestressed steel strand through the lower chord of the opening into the opening area, and leave anchor plates and spiral stirrups at both ends.
[0033] Step 8: Pour the beams and columns of the frame structure, and ensure that the opening area is compacted by vibration.
[0034] Step 9: When the concrete reaches the corresponding strength, the prestressing tendons are tensioned and prestressed.
[0035] Step 10: Repeat the above manufacturing process to complete the large-span prestressed concrete open beam frame structure system reinforced with steel profiles.
[0036] Compared with the prior art, the advantages of this utility model are:
[0037] 1. The utility model combines a post-tensioned bonded prestressed concrete open beam frame structure with a steel-concrete composite structure. It takes advantage of the advantages of steel-concrete composite structure, such as convenient and fast construction, good construction quality, energy saving and environmental protection, and combines the advantages of post-tensioned bonded prestressed structure, such as improved structural performance, reduced component cross-sectional height, reduced self-weight, improved component crack resistance and self-recovery, thereby improving the seismic performance of the overall frame structure.
[0038] 2. This utility model uses steel-concrete composite material, which, when applied to the opening area, enables a reliable connection between the upper and lower chords of the opening and the complete concrete beam. This not only improves the load-bearing capacity and seismic performance of the opening area, but also significantly reduces the amount of reinforcing steel and stirrups used in the opening area, thereby avoiding steel congestion in the opening area. Furthermore, it greatly improves the efficiency and construction quality of the precast beam and column components in terms of manufacturing, transportation, and installation. Attached Figure Description
[0039] Figure 1 This is a structural schematic diagram of the large-span prestressed concrete open beam frame structure system reinforced with steel profiles according to this utility model;
[0040] Figure 2 This is a front view of the opening reinforcement of the large-span prestressed concrete open beam frame structure system reinforced with steel profiles, which is a feature of this utility model.
[0041] Figure 3 This is a side sectional view of the reinforcement details at the opening of the large-span prestressed concrete open beam frame structure system reinforced with steel profiles, which is part of this utility model.
[0042] The correspondence between the reference numerals and components in the attached drawings is as follows: stress concrete beam (1), ordinary continuous steel bar (2), upper and lower chord corner bars of the opening (3), prestressed tendon (4), reinforcing stirrups on the side of the opening (5), upper and lower chord stirrups of the opening (6), reinforcing diagonal bars on the side of the opening (7), and steel section for reinforcing the opening (8). Detailed Implementation
[0043] To make the features, objectives and advantages of this utility model easier to understand, the utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0044] like Figure 1-3 As shown, the present invention describes a steel-reinforced large-span prestressed concrete beam frame structure system with openings, including a prestressed concrete beam (1), prestressed tendons (4), ordinary continuous steel bars (2), steel for opening reinforcement (8), upper and lower chord stirrups (6), upper and lower chord corner bars (3), reinforcing stirrups (5) on the side of the opening, and reinforcing diagonal bars (7) on the side of the opening.
[0045] The concrete beam opening is provided with prestressed tendons (4), ordinary continuous steel bars (2), structural steel (8), opening upper and lower chord stirrups (6), opening upper and lower chord corner bars (3), opening side reinforcing stirrups (5), and opening side reinforcing diagonal bars (7). The opening reinforcement structural steel (8) is fixed by the opening upper and lower chord stirrups (6), opening upper and lower chord corner bars (3), and opening side reinforcing diagonal bars (7).
[0046] The steel section (8) is located at the geometric centroid of the upper and lower chords of the opening. The steel section preferably presents an I-shaped cross-section, and the selection of the steel section can also be designed according to requirements.
[0047] The described steel section (8) is placed inside the stirrups (6) of the upper and lower chords of the opening. The steel section (8) is fixed by the upper and lower chord stirrups (6), the upper and lower chord corner bars (3) of the opening, and the reinforcing diagonal bars (7) on the side of the opening. The upper and lower chord stirrups (6) of the opening present a rectangular shape.
[0048] The upper and lower chord corner bars (3) of the opening extend out of the opening area and are directly anchored to the adjacent intact concrete beam. The design and anchorage length of the upper and lower chord corner bars (3) are designed according to requirements.
[0049] The reinforcing diagonal bars (7) on the side of the opening are placed inside the upper and lower chords of the opening and need to be bent in the area on the side of the opening. The reinforcing diagonal bars (7) on the side of the opening present a shape like the Chinese character "ji". The design of the reinforcing diagonal bars (7) on the side of the opening is designed according to requirements. The position of the reinforcing diagonal bars (7) on the side of the opening needs to pass through the area on the side of the opening.
[0050] The prestressed concrete beam (1) also includes a fully precast prestressed concrete beam and a cast-in-place concrete beam. The opening of the prestressed concrete beam (1) is located at the geometric center of the concrete section.
[0051] The bonded prestressing tendons (4) include straight, broken-line, and curved prestressing tendons.
[0052] The bonded prestressing tendons (4) can be bonded, partially bonded and unbonded, or unbonded in the opening area.
[0053] The prestressing tendons (4) adopt a post-tensioning construction method. The prestressing tendons (4) are tensioned after the concrete strength reaches the design requirements. After the tensioning is completed, the supports are removed.
[0054] Before the steel-concrete, prestressed concrete, and diagonal reinforcement of the opening are strengthened, the construction check calculation is carried out according to the force transfer mode suitable for the ordinary concrete beam. After the concrete beam and the upper and lower chords of the opening are poured and the concrete strength of the concrete beam and the upper and lower chords of the opening reaches the design requirements, the bonded prestressing tendons (4) are tensioned. After the tensioning is completed, the construction stage check calculation is carried out according to the unbonded frame beam; at the normal service limit state, the calculation is carried out according to the effective prestress. At the ultimate bearing limit state, the stress increment of the unbonded tendons is considered. Under seismic loads, the restoring performance provided by the unbonded tendons is considered.
[0055] The steel bars of the ordinary reinforced concrete beam (except the opening area) are tied according to the construction drawings. The stirrups are divided into the encrypted area and the non-encrypted area, and the reinforcement is arranged according to the design requirements.
[0056] The reinforcing stirrups (5) on the side of the opening, the corner bars (3) on the upper and lower chords of the opening, and the stirrups (6) on the upper and lower chords of the opening are tied in the corresponding positions. The reinforcement design is carried out in accordance with the relevant specifications.
[0057] The steel section (8) is placed in the upper and lower chords of the opening and fixed by the upper and lower chord stirrups (6), the upper and lower chord corner bars (3), and the reinforcing diagonal bars (7) on the side of the opening.
[0058] The prestressing tendon (4) is installed inside the concrete beam member, passes through the lower chord of the opening, and extends beyond the concrete beam at both ends. Clamps and anchors are fixedly installed at both ends. The linearity of the prestressing tendon (4) must satisfy the requirements of the prestressed concrete beam (1) and avoid the opening area. Specifically, the distance between the prestressing tendon and the opening must be more than 1 times the beam height.
[0059] Furthermore, when pouring concrete, pay special attention to vibration in the opening area.
[0060] A steel-reinforced, large-span prestressed concrete open beam frame structure system, characterized by comprising the following steps:
[0061] Step 1: The reinforcement of the columns and prestressed concrete beams (excluding the opening area) of the prestressed concrete frame is designed and tied according to the normal prestressed concrete frame. For the convenience of subsequent construction, the upper and lower chord stirrups (6) in the opening area, the stirrups (5) on the side of the opening, and the reinforcing diagonal bars (7) on the side of the opening should be placed in the opening area in advance.
[0062] Step 2: Tie the stirrups (5) on the side of the opening in the appropriate positions according to the construction drawings. The design of the stirrups (5) on the side of the opening needs to take into account the steel section (8) to avoid conflicts between the positions of the stirrups (5) and the steel section (8).
[0063] Step 3: For the convenience of subsequent construction, the steel section (8) needs to be temporarily placed into the upper and lower chords of the opening, passing through the upper and lower chord stirrups (6) of the opening, and temporarily fixed by the upper and lower chord stirrups (6), the upper and lower chord corner bars (3) of the opening, and the reinforcing diagonal bars (7) on the side of the opening.
[0064] Step 4: First, insert the reinforcing diagonal bars (7) on the side of the opening into the stirrups (6) of the upper and lower chords of the opening and fix them temporarily. At the same time, insert the corner bars (3) of the upper and lower chords of the opening into the stirrups (6) of the upper and lower chords of the opening and fix them temporarily.
[0065] Step 5: According to the construction drawings, tie the reinforcing diagonal bars (7) on the side of the opening, the corner bars (3) of the upper and lower chords of the opening, and the stirrups (6) of the upper and lower chords to the appropriate positions. First, the stirrups (6) of the upper and lower chords should be tied and fixed. Second, the reinforcing diagonal bars (7) on the side of the opening should be fixed to the reinforcing diagonal bars (7) and the stirrups (6) of the upper and lower chords of the opening. Finally, the corner bars (3) of the upper and lower chords of the opening should be placed at the corners of the stirrups (6) of the upper and lower chords (excluding the corners of the continuous reinforcing bars).
[0066] Step 6: According to the construction drawings, check the stirrups (6) of the upper and lower chords of the opening, the corner bars (3) of the upper and lower chords of the opening, and the reinforcing diagonal bars (7) on the side of the opening. The steel section (8) should be placed at the geometric center of the upper and lower chords of the two openings, and the position of the steel section (8) is fixed by the stirrups (6) of the upper and lower chords of the opening, the corner bars (3) of the upper and lower chords of the opening, and the reinforcing diagonal bars (7) on the side of the opening.
[0067] Step 7: Pass the prestressing tendon (4) through the lower chord of the opening and fix the prestressing tendon (4) according to the construction drawings. Anchor plates and spiral stirrups are left at both ends of the prestressed concrete for tensioning the prestressing tendon (4).
[0068] Step 8: When pouring the prestressed concrete frame, the frame columns should be poured first. Next, pour the concrete within the height range of the lower chord beams in the opening area and nearby areas, using a concrete vibrator for oblique compaction. Finally, pour the concrete in the opening area and the remaining parts of the prestressed concrete beams. Ensure the opening area is thoroughly compacted.
[0069] Step 9: Before applying prestress to the prestressing tendons (4), the appearance and dimensions of the member should be inspected. Tensioning can only proceed when the appearance and dimensions of the member meet the quality standard requirements. During tensioning, the concrete strength of the member should meet the design requirements. If not specified in the design, the concrete strength should not be less than 75% of the design strength grade value.
[0070] Step 10: Repeat the above manufacturing process to complete the large-span prestressed concrete open beam frame structure system reinforced with steel profiles.
[0071] The above description is merely an exemplary description of the present utility model. Obviously, the specific implementation of the present utility model is not limited to the above-described manner. That is, the description is not restrictive. Without departing from the methodological concept and technical solution of the present utility model, the present utility model can be easily improved, changed or replaced in various ways, and all such improvements and changes fall within the protection scope of the present utility model.
Claims
1. A large-span prestressed concrete open-hole beam frame structure system reinforced with section steel, characterized in that, It includes a prestressed concrete beam (1), prestressing tendons (4), ordinary longitudinal bars (2), steel sections (8) for opening reinforcement, upper and lower chord stirrups (6) of the opening, upper and lower chord corner bars (3) of the opening, stirrups (5) for strengthening the side of the opening, and diagonal bars (7) for strengthening the side of the opening. The steel sections (8) for opening reinforcement, upper and lower chord stirrups (6) of the opening, upper and lower chord corner bars (3) of the opening, prestressing tendons (4) and ordinary longitudinal bars (2) are arranged inside the upper and lower chords of the opening of the prestressed concrete beam (1). Stirrups (5) for strengthening the side of the opening and diagonal bars (7) for strengthening the side of the opening are arranged on the side of the opening of the prestressed concrete beam (1). The steel sections (8) for opening reinforcement are fixed by the upper and lower chord stirrups (6) of the opening, upper and lower chord corner bars (3) of the opening and diagonal bars (7) for strengthening the side of the opening. The prestressed concrete beam (1) includes a fully precast prestressed concrete beam. The prestressing tendons (4) include straight, broken-line and curved prestressing tendons. The construction method of post-tensioning is adopted for the prestressing tendons. The prestressing tendons (4) can be bonded, partially bonded and unbonded, unbonded inside the prestressed concrete beam (1). After the prestressing tendons (4) are tensioned, the supports are removed.
2. The long-span prestressed concrete opening beam frame structure system reinforced by section steel according to claim 1, characterized in that, The distance between the prestressing tendons and the opening meets the requirement of more than one beam height.
3. The long-span prestressed concrete opening beam frame structure system reinforced by section steel according to claim 1, characterized in that, The steel section presents an I shape.
4. The long-span prestressed concrete opening beam frame structure system reinforced by section steel according to claim 1, characterized in that, The upper and lower chord stirrups (6) of the opening present a square shape.
5. The long-span prestressed concrete opening beam frame structure system reinforced by section steel according to claim 1, characterized in that, The diagonal bars (7) for strengthening the side of the opening present a chevron shape. The position of the diagonal bars (7) for strengthening the side of the opening needs to pass through the area on the side of the opening.
6. The long-span prestressed concrete opening beam frame structure system reinforced by section steel according to claim 1, characterized in that, The opening of the prestressed concrete beam (1) is located at the geometric center of the concrete section.