Prefabricated cap beam structure

Abstract

This invention relates to the field of bridge engineering, and more specifically, to a prefabricated cap beam structure, comprising an upper structure, an intermediate connecting structure, and a lower structure arranged sequentially from top to bottom. The upper and lower structures are prefabricated, while the intermediate connecting structure is cast-in-place. The upper surface of the lower structure has an upward-opening connecting groove, and the intermediate connecting structure is cast into the connecting groove to secure the upper and lower structures together. The upper structure is a hollow member with an inverted U-shaped cross-section, including two parallel and oppositely arranged side plates and a top plate connected to the top of the two side plates. The bottoms of the two side plates are supported on the intermediate connecting structure, and the side plates and the top plate together form a continuous cavity extending along the length of the cap beam. The hollow upper structure reduces the weight of the entire cap beam while ensuring sufficient load-bearing capacity, reducing reliance on large transport vehicles and heavy lifting equipment, and also reducing the requirements for piers and foundations.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering, and more specifically, to a prefabricated cap beam structure. Background Technology

[0002] In bridge engineering, the cap beam, as a key force-transmitting component connecting the upper beams and lower piers, directly affects the safety, durability, and economy of the entire bridge structure. Traditionally, cap beams are mainly constructed using on-site monolithic casting. While this method ensures the integrity and continuity of the structure, it has many inherent drawbacks, including long construction periods, large amounts of formwork and support work, high difficulty in on-site quality control, significant environmental impact, and labor intensity. It is no longer suitable for the urgent needs of modern bridge engineering for industrialized, green, and rapid construction.

[0003] To overcome the shortcomings of cast-in-place construction, precast bridge technology has emerged as an important development direction. Factory prefabrication allows for standardized production in a controlled indoor environment. Through precise control of concrete mix proportions, pouring and vibration, and temperature and humidity curing, the intrinsic quality and batch consistency of components are significantly improved. Simultaneously, it greatly reduces on-site formwork work and labor intensity, improving construction efficiency and environmental friendliness. However, significant technical challenges remain in the practical application of precast cap beams. Traditional solid or large-volume precast cap beams, due to their heavy weight, place stringent requirements on the tonnage of transport vehicles and hoisting equipment, as well as on-site operating space. This makes them particularly difficult to apply in restricted scenarios such as cross-line operations, mountainous areas, or densely populated urban areas, resulting in poor economic efficiency. Summary of the Invention

[0004] This invention aims to overcome at least one of the defects (deficiencies) of the prior art and provide a prefabricated cap beam structure to solve the problems of long construction cycle, large amount of formwork support engineering, high difficulty in on-site quality control, serious interference to the surrounding environment and labor intensity of integral cast-in-place cap beams, as well as the demanding requirements on the tonnage of transport vehicles and hoisting equipment and on-site working space due to the heavy weight of integral prefabricated cap beams.

[0005] The technical solution adopted by this invention is a prefabricated cap beam structure with an approximately inverted T-shaped cross-section, comprising an upper structure, an intermediate connecting structure, and a lower structure arranged sequentially from top to bottom. The upper and lower structures are prefabricated, while the intermediate connecting structure is a cast-in-place structure. The upper surface of the lower structure is provided with an upward-opening connecting groove, and the intermediate connecting structure is cast into the connecting groove to solidify the upper and lower structures into one unit. The upper structure is a hollow component with an inverted U-shaped cross-section, comprising two parallel and oppositely arranged side plates and a top plate connected to the top of the two side plates. The bottoms of the two side plates are supported on the intermediate connecting structure, and the side plates and the top plate together form a continuous cavity extending along the length of the cap beam.

[0006] By casting an intermediate connecting structure on-site within the connecting groove of the substructure, a reliable connection between the superstructure and substructure is achieved, ensuring the integrity of the entire cap beam structure. The superstructure adopts an inverted U-shaped hollow structure, significantly reducing concrete usage while ensuring sufficient load-bearing capacity, thus significantly reducing the overall weight of the cap beam structure. This directly reduces reliance on large transport vehicles and heavy lifting equipment, making the cap beam applicable in space- and load-bearing-constrained scenarios such as cross-line operations, mountainous areas, and densely populated urban areas, significantly improving economic efficiency. The reduced weight of the cap beam structure also reduces the requirements for piers and their foundations, allowing for smaller pier and foundation dimensions and reinforcement. The superstructure and substructure are prefabricated in the factory, ensuring controllable quality and high precision, and avoiding large-scale on-site formwork. On-site work only involves casting the connecting groove, resulting in a short construction period, simple on-site operations, minimal impact on the surrounding environment, and reduced labor requirements.

[0007] To further enhance the reliability of the connection between the precast superstructure and the cast-in-place intermediate connection structure, a horizontally extended support is provided at the bottom of the side plate. This support effectively increases the contact and anchorage area between the bottom of the side plate and the cast-in-place concrete (intermediate connection structure), thereby significantly improving the connection reliability at the joint and the overall integrity of the cap beam structure. The support extends to both sides of the side plate, specifically including an inner extension extending into the continuous cavity and an outer extension extending away from the continuous cavity. This structure significantly increases the contact and mechanical engagement area between the bottom of the side plate and the cast-in-place intermediate connection structure, making load transfer smoother and greatly enhancing the shear and pull-out resistance of the joint.

[0008] In the precast superstructure, the corner between the inner surface of the side plate facing the continuous cavity and the lower surface of the top plate is chamfered. Chamfering at the inner corner effectively alleviates stress concentration, improves the density of the poured concrete, and thus significantly enhances the crack resistance and durability of the component.

[0009] Within the side panels of the superstructure, multiple first prestressing tendons are arranged along their length. The projection of each first prestressing tendon in the vertical plane is concave, lower in the middle and higher at both ends. The arrangement of these concave first prestressing tendons generates an upward vertical force in the superstructure to resist the downward bending moment caused by external loads. The horizontal force generated by the first prestressing tendons compresses the superstructure and also strengthens the connection between the bottom of the side panels and the intermediate connecting structure.

[0010] To further achieve lightweighting of the cap beam structure, a weight-reducing groove extending along its length is provided at the bottom of the substructure. This groove is concave upwards and does not penetrate the substructure, forming supporting sidewalls on both sides. These sidewalls, together with the solid portion above the groove, form an I-shaped or inverted U-shaped cross-section, significantly improving the bending stiffness and load-bearing efficiency of the substructure and the cap beam as a whole. This substructure, while ensuring sufficient load-bearing capacity, minimizes the self-weight of the cap beam structure, facilitating transportation and hoisting, and reducing the requirements for piers and foundations.

[0011] Multiple second prestressing tendons are arranged along the length of the supporting sidewall. The projection of the second prestressing tendons in the vertical plane is concave in the middle and high at both ends to improve the bending load-bearing capacity of the supporting sidewall. When the cap beam is in use, its two ends are supported on the piers. The bending moment in the middle is the largest and it is most prone to cracking. The concave second prestressing tendons arranged along the length of the supporting sidewall create an upward arching effect in the lower structure, which cancels out the downward deflection of the external load. This reduces the deformation of the cap beam during use and allows it to withstand greater loads.

[0012] The horizontal thickness at both ends of the supporting sidewall is greater than that at the middle. During use, the vertical shear force on the ends of the cap beam is greater than that at the middle, while the bending moment is greatest at the middle, but the shear force is relatively smaller. Therefore, the horizontal thickness at both ends of the supporting sidewall is set to be greater. In addition, a second prestressing tendon is provided within the supporting sidewall. Making the ends of the supporting sidewall thicker can prevent them from being damaged or crushed by the prestressing anchors. Preferably, the horizontal thickness at both ends of the supporting sidewall is 1.2-1.5 times that of the middle horizontal thickness, to maximize weight reduction while ensuring sufficient shear resistance and load-bearing capacity.

[0013] The inner surface of the supporting sidewall facing the weight-reducing groove transitions with the upper surface of the groove through multiple zigzag lines. This multi-segmented haunch structure, formed by these zigzag lines, decomposes the severe stress concentration that would normally occur at right-angle turns into multiple smooth transitions, providing a longer path for internal force transmission and significantly reducing the peak principal tensile stress in critical areas. This fundamentally suppresses the generation and development of diagonal cracks at the corners of the weight-reducing groove, effectively ensuring the integrity of the collaborative work between the supporting sidewall and the solid portion above the weight-reducing groove, and improving the fatigue resistance of the structure under long-term repeated loading. Furthermore, this design also offers excellent construction friendliness: the zigzag shape facilitates precise fabrication of precast formwork and dense concrete pouring, avoiding excessive reinforcement density at bends and ensuring the quality of concrete pouring in critical areas.

[0014] Compared with existing technologies, the beneficial effects of this invention are as follows: The cap beam structure is decomposed into an upper structure, a middle connecting structure, and a lower structure. Both the upper and lower structures are prefabricated to improve the internal quality and batch consistency of the components. The middle connecting structure is cast in-situ to ensure the strong connection between the upper and lower structures and the overall integrity of the cap beam structure. On-site construction only requires casting the middle connecting structure (connecting groove), simplifying the on-site operation, shortening the construction period, minimizing the impact on the surrounding environment, and eliminating the need for a large workforce on-site. The separate prefabrication of the upper and lower structures, with the upper structure being hollow and the lower structure having a weight-reducing groove at the bottom, significantly reduces concrete usage and the weight of the prefabricated components. This reduces reliance on large transport vehicles and heavy lifting equipment, making the cap beam suitable for applications with limited space or load, such as cross-line operations, mountainous areas, and densely populated urban areas, significantly improving economic efficiency. The reduced weight of the upper and lower structures also allows for a reduction in the size of the lower piers and foundations, as well as the reinforcement requirements. In the precast superstructure, the corner between the inner surface of the side panel and the lower surface of the top panel is chamfered. This effectively alleviates stress concentration, facilitates formwork installation, and improves the density of the concrete pouring, thereby enhancing the crack resistance and durability of the superstructure. Multiple first prestressing tendons are provided in the side panel, each tendon having a concave shape along the length of the side panel, lower in the middle and higher at both ends. The prestress generated by the first prestressing tendons produces an equivalent vertical upward force and a horizontal compressive force. The vertical upward force effectively resists external loads, while the horizontal compressive force enhances the connection strength between the bottom of the side panel and the intermediate connecting structure. To further improve the strength of the connection between the side panel and the intermediate connecting structure, a horizontally extended support portion is provided at the bottom of the supporting side panel to increase the contact area and anchorage area between the bottom of the side panel and the intermediate connecting structure. The support portion is integrally formed with the side panel and extends to both sides of the side panel, specifically including an inner extension and an outer extension. The inner extension extends into the continuous cavity, limited only by the size of the cavity; the outer extension extends outwards from the side plate, requiring consideration of the positions of the pad stones and supports on the substructure and the outer side of the superstructure. Therefore, the length of the inner extension can be greater than that of the outer extension. In the substructure, the weight-reducing groove forms supporting side plates on both sides. These supporting side plates, together with the solid portion above the weight-reducing groove, form an I-shaped or inverted U-shaped cross-section, improving the bending stiffness and load-bearing efficiency of the substructure. This achieves weight reduction without compromising its stiffness and load-bearing capacity. During use, the cap beam is supported at both ends by piers, experiencing significant shear forces. Therefore, the thickness of the supporting sidewall is designed to be maximum in the corresponding pier support area and gradually decreases towards the mid-span region. This provides the maximum effective cross-section for the critical shear-resistant area without significantly increasing its self-weight, improving the shear safety at the base of the cap beam.Meanwhile, the bending moment is greatest in the middle of the cap beam. Multiple second prestressing tendons, high at both ends and low in the middle, are pre-embedded along the length of the support sidewall. This actively establishes the required prestress in the central region, thereby improving the bending capacity and stiffness of the substructure and the cap beam as a whole. Thickening the ends of the support sidewall also prevents it from being damaged by the anchorages securing the second prestressing tendons. Setting the horizontal thickness at both ends of the support sidewall to 1.2-1.5 times its central horizontal thickness maximizes weight reduction while ensuring sufficient shear resistance and load-bearing capacity. The inner surface of the support sidewall and the upper surface of the weight-reducing groove are transitioned through multiple zigzag lines, forming a multi-segmented haunch structure. This provides a longer path for internal force transmission, fundamentally suppressing the generation and development of diagonal cracks at the corners of the weight-reducing groove, and ensuring the integrity of the support sidewall and the solid portion above the weight-reducing groove working together. Furthermore, the zigzag shape facilitates the precise processing and installation of precast formwork, as well as the pouring and vibration of concrete, thus ensuring the quality of concrete pouring in critical areas. Attached Figure Description

[0015] Figure 1 This is a structural diagram of the present invention.

[0016] Figure 2 This is a structural diagram of the present invention from another angle.

[0017] Figure 3 This is the right view of the present invention.

[0018] Figure 4 This is a sectional view of AA.

[0019] Figure 5 This is a sectional view of BB.

[0020] Figure 6 This is a schematic diagram of the first and second prestressing tendons.

[0021] Figure 7 This is a schematic diagram of multiple cap beam structures connected longitudinally.

[0022] Figure 8 This is a sectional view of CC.

[0023] 100. Superstructure; 110. Side plate; 120. Top plate; 130. Continuous cavity; 140. First prestressing tendon; 150. Support section; 151. Inner extension; 152. Outer extension; 200. Intermediate connecting structure; 300. Substructure; 310. Supporting platform; 320. Connecting groove; 330. Weight reduction groove; 340. Supporting sidewall; 350. Second prestressing tendon; 360. End plate; 370. Diaphragm; 400. Third prestressing tendon; 500. Pier column. Detailed Implementation

[0024] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate the following embodiments, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; it is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0025] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] like Figure 1 , Figure 4 As shown, a prefabricated cap beam structure has an approximately inverted T-shaped cross-section and includes an upper structure 100, an intermediate connecting structure 200, and a lower structure 300 arranged sequentially from top to bottom. Both the upper structure 100 and the lower structure 300 are prefabricated, with the upper structure 100 positioned above the lower structure 300. The upper surface of the lower structure 300 has an upward-opening connecting groove 320. The intermediate connecting structure 200 is a cast-in-place structure, cast within the connecting groove 320, used to solidify the upper structure 100 and the lower structure 300 into a single unit. The width B1 of the upper structure 100 is smaller than the width B2 of the lower structure 300, thereby forming a support platform 310 on the upper surface of the lower structure 300 and the intermediate connecting structure 200, and on the outer side of the upper structure 100, for supporting the ends of the beam slab.

[0027] Specifically, such as Figures 4-6As shown, the upper structure 100 is a hollow component with an inverted U-shaped cross-section, including two parallel and oppositely arranged side plates 110, and a top plate 120 connected to the top of the two side plates 110. The bottoms of the two side plates 110 are supported on the intermediate connecting structure 200. The side plates 110 and the top plate 120 are integrally formed, together enclosing a continuous cavity 130 extending along the length of the cap beam. The corner between the inner surface of the side plate 110 facing the continuous cavity 130 and the lower surface of the top plate 120 is chamfered to effectively alleviate stress concentration at the corner and improve the compactness of the concrete pouring, thereby significantly improving the crack resistance and durability of the upper structure 100. Multiple first prestressing tendons 140 are arranged along the length of the two side plates 110. The projection of the first prestressing tendons 140 on the vertical plane is concave, with high ends and a low middle. The prestress generated by the first prestressing tendon 140 can produce an equivalent vertical upward force and a horizontal compressive force. The vertical upward force can directly offset part of the downward external load effect, while the horizontal compressive force can improve the connection strength between the bottom of the side plate 110 and the cast-in-place concrete (intermediate connecting structure 200). The horizontal force generated by the first prestressing tendon 140 in the side plate 110 is opposite in direction and points towards the center, which is equivalent to applying a continuous and active compressive force at both ends of the cast-in-place intermediate connecting structure 200, forming a "clamping" effect on the cast-in-place concrete, thereby improving the connection strength between the cast-in-place intermediate connecting structure 200 and the precast upper structure 100. At the bottom of the two side plates 110, a horizontally extended support portion 150 is also provided. The support portion 150 is integrally formed with the side plate 110 to increase the contact and anchorage area between the bottom of the side plate 110 and the cast-in-place intermediate connecting structure 200, thereby further improving the connection strength between the bottom of the side plate 110 and the intermediate connecting structure 200. The support portion 150 includes an inner extension 151 extending into the continuous cavity 130 and an outer extension 152 extending away from the continuous cavity 130, with the inner extension 151 extending a greater distance than the outer extension 152. The extension distance of the inner extension 151 is limited only by the size of the continuous cavity 130 and can be set to be relatively large; while the extension distance of the outer extension 152 needs to take into account the position of the pad stone or support, and therefore is set to be relatively small. The support platform 310 on the outer side of the superstructure 100 (away from the continuous cavity 130) is used to support the end of the beam plate. Pad stones and supports need to be set on the support platform 310. If the extension distance of the outer extension 152 is too large, it will affect the setting of the pad stone and support. Therefore, the extension distance of the outer extension 152 is smaller than that of the inner extension 151. The bottom of the two side plates 110 are provided with first connecting ribs (not shown) for connection with the lower structure 300.

[0028] like Figures 2-6As shown, the lower structure 300 is wider at the top and narrower at the bottom. Its upper surface has a connecting groove 320 extending along its length. A second connecting rib (not shown) is pre-installed in the connecting groove 320 for connection with a first connecting rib pre-installed in the upper structure 100. The bottom of the lower structure 300 has a weight-reducing groove 330 extending along its length. The weight-reducing groove 330 is concave upwards and does not penetrate the lower structure 300. Supporting sidewalls 340 are formed on both sides of the weight-reducing groove 330. The supporting sidewalls 340 and the solid portion above the weight-reducing groove 330 together form an I-shaped or inverted U-shaped cross-section, which can significantly improve the bending stiffness and load-bearing efficiency of the lower structure, thereby achieving weight reduction of the lower structure 300 without affecting its load-bearing capacity and stiffness. Figure 2As shown, to further optimize the load-bearing performance of the substructure, multiple transverse diaphragms 370 are spaced along the length of the weight-reducing groove 330. These diaphragms 370 connect the supporting sidewalls 340 on both sides, significantly improving the buckling stability of the supporting sidewalls 340 and thus significantly enhancing the overall structural integrity. The inner surface of the supporting sidewalls 340 facing the weight-reducing groove 330 transitions to the upper surface of the weight-reducing groove 330 through multiple zigzag lines. These zigzag lines form a multi-segmented haunch structure, decomposing the severe stress concentration that would easily occur at right-angle turns into multiple smooth transitions, providing a longer path for internal force transmission. This significantly reduces the peak principal tensile stress in critical areas, fundamentally suppressing the generation and development of diagonal cracks at the corners of the weight-reducing groove 330, and effectively ensuring the integrity of the coordinated work between the supporting sidewalls 340 and the solid portion above the weight-reducing groove 330. Furthermore, this design facilitates the precise processing of precast templates and the compaction of concrete pouring, ensuring the quality of concrete pouring in critical areas. Multiple second prestressing tendons 350 are arranged along the length of the supporting sidewall 340. The projection of the second prestressing tendons 350 in the vertical plane is concave, with higher ends and a lower middle. When in use, the cap beam is supported at both ends on the piers 500, with the middle section experiencing the greatest bending moment. The concave second prestressing tendons 350 within the supporting sidewall 340 create an upward arching effect in the lower structure 300, which can offset some of the downward external load effect and reduce deformation in the middle section during use. The cap beam is arranged transversely, with its length direction being the transverse direction (i.e., the width direction) of the bridge. During use, the ends of the beam are supported on the lower structure 300 (supporting platform 310) of the cap beam. The lower structure 300 bears a greater load than the upper structure 100; therefore, the number of second prestressing tendons 350 arranged in the supporting sidewall 340 is greater than the number of first prestressing tendons 140 arranged in the side plate 110. The horizontal thickness D1 at both ends of the supporting sidewall 340 is greater than the horizontal thickness D2 in its middle section, enabling it to withstand greater shear forces. The shear forces borne by the ends of the lower structure 300 are greater than those in the middle. Furthermore, the anchors used to secure the second prestressed tendons 350 need to be fixed to both ends of the supporting sidewall 340. If the horizontal thickness D1 at both ends of the supporting sidewall 340 is too small, it may be damaged or crushed by the anchors. Therefore, the horizontal thickness D1 at both ends of the supporting sidewall 340 is set to be larger. Preferably, the horizontal thickness D1 at both ends of the supporting sidewall 340 is 1.2-1.5 times the horizontal thickness D2 in its middle section, to maximize weight reduction while ensuring sufficient shear resistance and load-bearing capacity. If the ratio of D1 to D2 is too large (greater than 1.5), the shear resistance and load-bearing capacity at both ends of the lower structure 300 may meet the requirements, but the middle section may be insufficient. Alternatively, while the middle section may meet the requirements, the horizontal thickness at both ends may be excessive, unreasonably increasing the weight.If the ratio is too small (less than 1.2), it may result in insufficient shear resistance at both ends or excessive thickness in the middle, unreasonably increasing the weight. The weight-reducing groove 330 is provided with end plates 360 at both ends, which connect to the two ends of the supporting sidewalls 340 to enhance the overall structural integrity at both ends.

[0029] like Figure 4 , Figure 5 As shown, the intermediate connecting structure 200 is cast in the connecting groove 320 on site to tightly connect the prefabricated upper structure 100 and lower structure 300 into one unit, achieving the same overall load-bearing performance as cast-in-place structures.

[0030] During construction, firstly, the precast lower structure 300 is hoisted to the top of the pier 500 and temporarily fixed. Then, the concrete contact surface within the connecting groove 320 and the lower surface of the support portion 150 are roughened, cleaned, and moistened. Next, the precast upper structure 100 is hoisted above the lower structure 300, and the first connecting bar extending from the support portion 150 is reliably connected to the second connecting bar extending from the connecting groove 320, forming a connecting steel reinforcement skeleton. Afterward, formwork is erected around the connecting groove 320, and concrete is poured to fully fill the connecting groove 320. Finally, the poured concrete is cured according to specifications, and once it reaches the design strength, the intermediate connecting structure 200 is formed.

[0031] like Figure 7 , Figure 8 As shown, the length of the cap beam structure can be selected according to design requirements. When the actual bridge deck width is greater than the bearing width of a single cap beam, multiple cap beam structures can be connected side-by-side along the transverse direction (i.e., the length direction of the cap beam structure). To achieve this connection and ensure overall load-bearing performance, ducts for inserting third prestressing tendons 400 are pre-embedded in the connection ends of adjacent cap beams. During installation, the third prestressing tendons 400 are inserted into the aligned ducts of adjacent cap beams and tensioned and anchored. The third prestressing tendons 400 can be arranged in a concave shape with a high middle and low ends in the vertical plane, so that downward prestress is generated at the connection. After tensioning, a wet joint of post-cast concrete can be used to achieve concrete continuity and cross-sectional restoration, obtaining a structural appearance and performance indistinguishable from the overall precast structure. For the connected cap beams, no end plate 360 ​​is set at the connection end; an end plate 360 ​​is only set at the other end of the connection end.

[0032] This prefabricated cap beam structure first prefabricates the upper structure 100 and the lower structure 300, then firmly connects them on-site via a cast-in-place central connecting structure 200, giving it the same overall load-bearing performance as cast-in-place structures. On-site construction only requires pouring the central connecting structure, simplifying the work, shortening the construction period, and minimizing environmental impact. The upper structure 100 and lower structure 300 can be transported and hoisted separately. Furthermore, the upper structure 100 is designed as a hollow structure, and the lower structure 300 incorporates weight-reducing grooves, significantly reducing concrete usage and the weight of the prefabricated components, thus reducing reliance on large transport vehicles and heavy hoisting equipment. The reduced weight of the cap beam also allows for smaller dimensions and less stringent reinforcement requirements for the lower piers 500 and foundations.

[0033] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A prefabricated cap beam structure, the cross-section of which is approximately inverted T-shaped, characterized in that, The structure comprises an upper structure, an intermediate connecting structure, and a lower structure arranged sequentially from top to bottom. The upper and lower structures are prefabricated, while the intermediate connecting structure is cast-in-place. The upper surface of the lower structure has an upward-opening connecting groove, and the intermediate connecting structure is cast into the connecting groove to secure the upper and lower structures together. The upper structure is a hollow component with an inverted U-shaped cross-section, comprising two parallel and oppositely arranged side plates and a top plate connected to the top of the two side plates. The bottoms of the two side plates are supported on the intermediate connecting structure, and the side plates and the top plate together form a continuous cavity extending along the length of the cap beam.

2. The prefabricated cap beam structure according to claim 1, characterized in that, The bottom of the side plate is provided with a horizontally extended support portion to increase the contact area between the side plate and the intermediate connecting structure.

3. The prefabricated cap beam structure according to claim 2, characterized in that, The supporting portion includes an inner extension extending into the continuous cavity and an outer extension extending away from the continuous cavity.

4. The prefabricated cap beam structure according to claim 1, characterized in that, In the prefabricated superstructure, the corner between the inner surface of the side plate facing the continuous cavity and the lower surface of the top plate is chamfered.

5. The prefabricated cap beam structure according to claim 1, characterized in that, The side plate of the upper structure is provided with a plurality of first prestressing tendons along its length. The projection of the first prestressing tendons in the vertical plane is concave in shape with a low middle and high ends.

6. The prefabricated cap beam structure according to any one of claims 1-5, characterized in that, The bottom of the lower structure is provided with a weight-reducing groove extending along its length; the weight-reducing groove is recessed upward and does not penetrate the lower structure, and its two sides form supporting sidewalls.

7. The prefabricated cap beam structure according to claim 6, characterized in that, Multiple second prestressing tendons are provided along the length of the supporting sidewall. The projection of the second prestressing tendons in the vertical plane is concave in the middle and high at both ends, so as to improve the bending bearing capacity of the supporting sidewall.

8. The prefabricated cap beam structure according to claim 7, characterized in that, The horizontal thickness at both ends of the supporting sidewall is greater than the horizontal thickness in the middle.

9. The prefabricated cap beam structure according to claim 8, characterized in that, The horizontal thickness at both ends of the supporting sidewall is 1.2-1.5 times the horizontal thickness of its middle portion.

10. The prefabricated cap beam structure according to claim 6, characterized in that, The inner surface of the supporting sidewall facing the weight reduction groove and the upper surface of the weight reduction groove are transitioned by multiple broken lines.

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