Concrete folding beam structure with partial built-in steel ribs

Abstract

The invention discloses a concrete folding beam structure with partially built-in steel ribs, which comprises a concrete folding beam consisting of a high horizontal beam section, a vertical beam section and a low horizontal beam section, and supports respectively positioned at two ends of the concrete folding beam, the high horizontal beam section is internally provided with the high horizontal beam section steel rib arranged along the axial direction of the high horizontal beam section, the vertical beam section is internally provided with the vertical beam section steel rib, and the low horizontal beam section is internally provided with the low horizontal beam section steel rib. A low horizontal beam section steel rib arranged in the axial direction of the low horizontal beam section is arranged in the low horizontal beam section, the high horizontal beam section steel rib, the vertical beam section steel rib and the low horizontal beam section steel rib are connected end to end, and the sum of the axial lengths of the high horizontal beam section steel rib and the low horizontal beam section steel rib is smaller than the sum of the axial lengths of the high horizontal beam section and the low horizontal beam section. The outer sides of the horizontal beam section steel ribs, the vertical beam section steel ribs and the low horizontal beam section steel ribs are provided with reinforcing meshes which are integrally in a zigzag shape, and the two ends of the zigzag reinforcing meshes are connected with the corresponding supports respectively. The invention aims to realize the balance between the structural performance and the economic benefit by optimizing the steel rib configuration and the reinforcement design, and can be widely applied to the field of building beam column structures.

Description

Technical Field

[0001] The present invention relates to a building beam-column structure, in particular to a concrete folded beam structure with partially embedded steel profiles. Background Art

[0002] With the progress of society and the continuous improvement of people's living conditions, the architectural form design tends to be more complex, and the utilization of the internal space of buildings tends to be more diversified, which puts forward higher requirements for architectural structure design. Especially in the design of public buildings, column-free large spaces and changes in building floor elevations are becoming more and more common, which has an adverse impact on the structural layout. Therefore, in the structural design, we set large-span steel reinforced concrete folded beams to adapt to the changes in building elevations and meet the requirements of column-free large spaces. In reinforced concrete structures, vertical folded beams, as structural members in a folded shape in the vertical plane, are commonly seen in scenarios where complex architectural forms, spatial functions, or force-bearing requirements need to be adapted. When modern buildings pursue curved or folded facades, vertical folded beams can conform to the irregular facades, taking into account both aesthetics and structural functions. In split-level or stepped floor designs, folded beams form continuous supports at different elevations, coordinating the structural integrity. Its advantages lie in its flexible matching of irregular building planes or facades and its ability to reduce the occupied structural height and increase the clear height.

[0003] The technical problem to be solved by the present invention is the configuration problem of steel profiles and steel bars in vertical reinforced concrete folded beams. The stress state at the turning section of a vertical folded beam is complex, and there are combined actions of bending moment, axial force, and shear force under the action of gravity load and lateral force. When the turning angle is large, the stress concentration effect is significant, and concrete cracking is likely to occur. The stress state at the connection of a folded beam is similar to that of a beam-column joint, and plastic hinges are likely to form at the turning section under large earthquake actions, exacerbating the unfavorable stress situation of the folded beam. The stress-bearing steel bars in the folded beam need to be bent multiple times or anchored to each other according to its turning angle, which weakens the reliability of the steel bar connection to a certain extent. For folded beams with small turning angles and small spans, the redundancy can be improved by increasing the reinforcement area; for folded beams with large turning angles or large spans, steel profiles are usually added to the folded beam to use the continuous steel profiles to bear the complex stress state at the turning section of the folded beam.

[0004] This is mainly because when traditional reinforced concrete folded beams bear vertical loads, stress concentration is likely to be caused by sudden changes in bending moments in the corner area, leading to concrete cracking and yielding of main reinforcement, thereby reducing the structural ductility and bearing capacity. Especially in large-span or high-intensity seismic fortification areas, ordinary reinforcement schemes are difficult to meet the shear and torsion resistance requirements of the folded beam joint area. Scholars at home and abroad have found through experiments that the crack development pattern at the fold of the folded beam is radially distributed, and the crack width is negatively correlated with the radius of curvature of the corner. There is an urgent need for innovative construction measures to improve its mechanical performance. The introduction of steel reinforced concrete structures provides a new idea for enhancing the load-bearing efficiency of folded beams. According to the "Code for Design of Composite Structures", the built-in steel skeleton can significantly enhance the flexural stiffness of components and delay the expansion of concrete cracks. Its core advantage lies in the material complementarity of steel and concrete: the steel skeleton bears the peak tensile and compressive stresses, while the surrounding concrete inhibits the local buckling of the steel skeleton.

[0005] The existing technical solution is to set steel skeletons throughout the length of the concrete vertical folded beam. The disadvantage of the existing technology is that setting steel skeletons throughout the length will cause relatively large material waste, especially when the beam span is large and the bending moment values at the mid-span or one side of the support are small. At the same time, setting steel skeletons throughout the length will complicate the beam-column joints, and additional steel skeletons in the columns need to be added for connection in the joints, resulting in increased construction difficulty.

[0006] In view of this situation, it is necessary to study a large-span concrete folded beam structure with partially built-in steel skeletons. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies of the above-mentioned background technology and provide a concrete folded beam structure with partially built-in steel skeletons, aiming to achieve a balance between structural performance and economic benefits through optimizing the steel skeleton configuration and reinforcement design.

[0008] A concrete folded beam structure with partially built-in steel skeletons provided by the present invention includes a concrete folded beam composed of a high-level beam section, a vertical beam section, and a low-level beam section, and supports located at both ends of the concrete folded beam respectively. The high-level beam section is internally provided with a high-level beam section steel skeleton arranged along its axial direction, the vertical beam section is internally provided with a vertical beam section steel skeleton, the low-level beam section is internally provided with a low-level beam section steel skeleton arranged along its axial direction. The high-level beam section steel skeleton, the vertical beam section steel skeleton, and the low-level beam section steel skeleton are connected end to end. The sum of the axial lengths of the high-level beam section steel skeleton and the low-level beam section steel skeleton is shorter than the sum of the axial lengths of the high-level beam section and the low-level beam section. An integrally folded steel mesh is arranged outside the high-level beam section steel skeleton, the vertical beam section steel skeleton, and the low-level beam section steel skeleton, and both ends of the folded steel mesh are respectively connected to the corresponding supports.

[0009] In the above technical solution, the top and bottom of the high-level beam section steel skeleton and the low-level beam section steel skeleton, as well as both sides of the vertical beam section steel skeleton, are flange plates. The flange plates at the top of the high-level beam section steel skeleton and the low-level beam section steel skeleton are connected to the flange plate on one side of the vertical beam section steel skeleton, and the flange plates at the bottom of the high-level beam section steel skeleton and the low-level beam section steel skeleton are connected to the flange plate on the other side of the vertical beam section steel skeleton. Above the flange plates at the top of the high-level beam section steel skeleton and the low-level beam section steel skeleton, multiple upper longitudinal steel bars within the width of the flange plate arranged along the axial direction of the flange plate are evenly distributed. Below the flange plates at the bottom of the high-level beam section steel skeleton and the low-level beam section steel skeleton, multiple lower longitudinal steel bars within the width of the flange plate arranged along the axial direction of the flange plate are respectively evenly distributed. The upper longitudinal steel bars within the width of the flange plate of the high-level beam section steel skeleton, and the lower longitudinal steel bars within the width of the flange plate of the high-level beam section steel skeleton and the low-level beam section steel skeleton all extend into the vertical beam section.

[0010] In the above technical solution, an inclined connecting plate is provided at the bottom where the high-level beam section steel skeleton intersects with the vertical beam section steel skeleton. The lower longitudinal steel bars within the width of the flange plate of the high-level beam section steel skeleton are connected to the inclined connecting plate and then extend vertically along the surface of the inclined connecting plate into the vertical beam section until below the low-level beam section steel skeleton and are bent. The lower longitudinal steel bars within the width of the flange plate of the low-level beam section steel skeleton are bent and extend into the vertical beam section. The lower longitudinal steel bars within the width of the flange plate of the high-level beam section steel skeleton are welded to the surface of the inclined connecting plate. The two ends of the inclined connecting plate and the connection parts of the high-level beam section steel skeleton and the vertical beam section steel skeleton are respectively a high-level connecting line and a low-level connecting line. A first stiffening plate vertically arranged is provided at the corresponding position of the high-level beam section steel skeleton and the high-level connecting line, and a second stiffening plate horizontally arranged is provided at the corresponding position of the vertical beam section steel skeleton and the low-level connecting line.

[0011] In the above technical solution, a cross orthogonal connecting plate is provided above the intersection of the vertical beam section steel skeleton and the low-level beam section steel skeleton. One end of the horizontal plate of the cross orthogonal connecting plate is connected to the flange plate of the vertical beam section steel skeleton, and one end of the vertical plate of the cross orthogonal connecting plate is connected to the flange plate at the top of the low-level beam section steel skeleton. The upper longitudinal steel bars within the width of the flange plate of the high-level beam section steel skeleton are welded to the surface of the vertical plate of the cross orthogonal connecting plate after entering the vertical beam section. The upper longitudinal steel bars within the width of the flange plate of the low-level beam section steel skeleton are welded to the surface of the horizontal plate of the cross orthogonal connecting plate. A third stiffening plate horizontally arranged is provided at the corresponding position of the vertical beam section steel skeleton and the horizontal plate of the cross orthogonal connecting plate within the vertical beam section steel skeleton, and a fourth stiffening plate vertically arranged is provided at the corresponding position of the low-level beam section steel skeleton and the vertical plate of the cross orthogonal connecting plate within the low-level beam section steel skeleton.

[0012] In the above technical solution, longitudinal steel bars outside the flange width are provided above the top and below the bottom of the high-level beam segment steel skeleton and the low-level beam segment steel skeleton, and also on the obliquely outer sides of the flange plates of the vertical beam segment steel skeleton. The ends of the longitudinal steel bars outside the flange width in the high-level beam segment and the low-level beam segment are bent in the extending direction of the vertical beam segment. The two ends of the longitudinal steel bars outside the flange width in the vertical beam segment are respectively bent in the extending directions of the high-level beam segment and the low-level beam segment. The high-level beam segment, the vertical beam segment, and the low-level beam segment are provided with multiple circles of stirrups arranged according to the axial cross-sections of each beam segment along their axial directions. The upper longitudinal steel bars within the flange width, the lower longitudinal steel bars within the flange width, and the longitudinal steel bars outside the flange width are all connected to the inner sides of the multiple circles of stirrups.

[0013] In the above technical solution, beam side waist steel bars are provided between the top and the bottom of the high-level beam segment and the low-level beam segment, and also between the longitudinal steel bars outside the flange width on both sides of the vertical beam segment. The ends of the beam side waist steel bars in the high-level beam segment and the low-level beam segment are bent in the extending direction of the vertical beam segment. The two ends of the beam side waist steel bars in the vertical beam segment are respectively bent in the extending directions of the high-level beam segment and the low-level beam segment. The beam side waist steel bars are all connected to the inner sides of the multiple circles of stirrups.

[0014] In the above technical solution, multiple inclined additional steel bars are provided in the concrete folded beam. The multiple inclined additional steel bars are arranged from high to low, and both ends pass through the vertical beam segment and extend into the high-level beam segment and the low-level beam segment respectively. The multiple inclined additional steel bars are symmetrically arranged on both sides of the corresponding high-level beam segment steel skeleton, vertical beam segment steel skeleton, and low-level beam segment steel skeleton. More than half of the length of the multiple inclined additional steel bars is located between the longitudinal steel bars outside the corresponding flange width. The multiple inclined additional steel bars are connected to the inner sides of the stirrups they pass through.

[0015] In the above technical solution, there is a gap between the bottom end of the upper longitudinal steel bars within the flange width of the high-level beam segment steel skeleton and the end of the upper longitudinal steel bars within the flange width of the low-level beam segment steel skeleton.

[0016] In the above technical solution, the spacing between the stirrups at the vertical beam segment steel skeleton and at the joints of the vertical beam segment steel skeleton with the high-level beam segment steel skeleton and the low-level beam segment steel skeleton in the concrete folded beam is smaller than the spacing between the stirrups at the beam segments outside the vertical beam segment steel skeleton and at the joints of the vertical beam segment steel skeleton with the high-level beam segment steel skeleton and the low-level beam segment steel skeleton in the concrete folded beam.

[0017] In the above technical solution, the axial length of the steel skeleton of the low-level beam segment is equal to or less than the axial length of the low-level beam segment, or the steel skeleton of the low-level beam segment extends along the low-level beam segment into the corresponding support; the bending length of the longitudinal reinforcement outside the width of the flange plate and the waist reinforcement on the side of the beam is not less than 15 times the diameter of the reinforcement; the inclined connecting plate and the inclined additional reinforcement are both at an angle of 45° to the horizontal plane; the stirrup is a two-leg stirrup or a four-leg stirrup; when the stirrup is a four-leg stirrup, the longitudinal reinforcement outside the width of the flange plate, the waist reinforcement on the side of the beam and the inclined additional reinforcement are all connected to the outer stirrup of the stirrup; when the stirrup is a two-leg stirrup, the diameter of the two-leg stirrup is greater than the diameter of the four-leg stirrup; the longitudinal reinforcement outside the width of the flange plate and the waist reinforcement on the side of the beam in the high-level beam segment are connected to the side wall of the corresponding support or extend into the support; when the end of the steel skeleton of the low-level beam segment is connected to the side wall of the corresponding support, the longitudinal reinforcement outside the width of the flange plate and the waist reinforcement on the side of the beam in the low-level beam segment are connected to the reinforcement of the side wall of the corresponding support; when the steel skeleton of the low-level beam segment extends along the low-level beam segment into the corresponding support, the longitudinal reinforcement and the waist reinforcement in the low-level beam segment extend into the corresponding support; multiple circles of stirrups at the steel skeleton of the vertical beam segment and at the joints of the steel skeleton of the vertical beam segment with the steel skeleton of the high-level beam segment and the steel skeleton of the vertical beam segment with the steel skeleton of the low-level beam segment in the concrete folded beam form a first stirrup reinforcement area, and a second stirrup reinforcement area is provided at the joints of the high-level beam segment and the low-level beam segment with the corresponding supports. The axial lengths of the first stirrup reinforcement area and the second stirrup reinforcement area are both not less than 1.5 times the beam height and not less than 500 mm; there are a total of four inclined additional reinforcements, among which, there are two on each side of the steel skeleton of the high-level beam segment, the steel skeleton of the vertical beam segment and the steel skeleton of the low-level beam segment; the total cross-sectional areas of the four inclined additional reinforcements are respectively not less than the total cross-sectional areas of the upper longitudinal reinforcements within the width of multiple flange plates and the total cross-sectional areas of the lower longitudinal reinforcements within the width of multiple flange plates; the diameters of the two upper inclined additional reinforcements are the same as the diameter of the largest-diameter reinforcement among the upper longitudinal reinforcements within the width of the flange plate and the longitudinal reinforcements outside the width of the flange plate; the diameters of the two lower inclined additional reinforcements are the same as the diameter of the largest-diameter reinforcement among the lower longitudinal reinforcements within the width of the flange plate and the longitudinal reinforcements outside the width of the flange plate; the upper longitudinal reinforcements within the width of the flange plate are connected by double-sided welding to the cross-shaped orthogonal connecting plate, and the lower longitudinal reinforcements within the width of the flange plate of the steel skeleton of the high-level beam segment are connected by double-sided welding to the surface of the inclined connecting plate; the steel skeletons of the high-level beam segment, the vertical beam segment and the low-level beam segment are I-beams or box-section steels. When the steel skeletons of the high-level beam segment, the vertical beam segment and the low-level beam segment are box-section steels, the top and bottom surfaces of the steel skeletons of the high-level beam segment and the low-level beam segment are respectively flange plates, and the side walls of the steel skeleton of the vertical beam segment connected to the flange plates of the steel skeletons of the high-level beam segment and the low-level beam segment are flange plates.

[0018] The concrete folded beam structure with partially built-in steel skeletons of the present invention has the following beneficial effects: Steel skeleton segmented layout: Based on the bending moment distribution characteristics, the steel skeleton is only arranged in the vertical beam segments with complex stress or the support extension areas with large bending moments, significantly reducing the steel consumption. Node structure simplification: Avoid the complex connection of the traditional full-length steel skeleton and the column node, reduce the requirement for embedded steel skeleton in the column, eliminate the spatial interference problem between the steel bars and the steel skeleton, and improve the construction convenience. Description of the drawings

[0019] Figure 1 It is a schematic diagram of the external overall structure of the concrete folded beam structure with partially embedded steel skeleton of the present invention; Figure 2 It is a schematic diagram of the internal structure of the longitudinal steel bars, steel skeleton, connecting plates and stiffening plates within the width of the flange plate of the concrete folded beam in Embodiment 1 of the concrete folded beam structure with partially embedded steel skeleton of the present invention; Figure 3 It is a cross-sectional view of the beam segment outside the first stirrup encryption zone in the high-level beam segment of Embodiment 1 of the concrete folded beam structure with partially embedded steel skeleton of the present invention; Figure 4 It is a schematic diagram of the internal structure of the longitudinal steel bars outside the width of the flange plate of the concrete folded beam, the waist steel bars on the side of the beam and the inclined additional steel bars in the concrete folded beam of Embodiment 1 of the concrete folded beam structure with partially embedded steel skeleton of the present invention; Figure 5 It is a cross-sectional view of the beam segment in the first stirrup encryption zone in the high-level beam segment of Embodiment 1 of the concrete folded beam structure with partially embedded steel skeleton of the present invention; Figure 6 It is a distribution diagram of the encrypted stirrups in the concrete folded beam of Embodiment 1 of the concrete folded beam structure with partially embedded steel skeleton of the present invention; Figure 7 It is a schematic diagram of the structure where the steel skeleton in the low-level beam segment of Embodiment 1 of the concrete folded beam structure with partially embedded steel skeleton of the present invention is connected to the side wall of the support; Figure 8 It is a schematic diagram of the structure where the longitudinal steel bars outside the width of the flange plate of the horizontal beam segment and the waist steel bars on the side of the beam in Embodiment 1 of the concrete folded beam structure with partially embedded steel skeleton of the present invention are connected to the side wall of the support; Figure 9 It is a schematic diagram of the structure where the steel skeleton in the low-level beam segment of Embodiment 2 of the concrete folded beam structure with partially embedded steel skeleton of the present invention enters the corresponding support; Figure 10 It is a schematic diagram of the structure where the longitudinal steel bars outside the width of the flange plate of the horizontal beam segment and the waist steel bars on the side of the beam in Embodiment 2 of the concrete folded beam structure with partially embedded steel skeleton of the present invention enter the corresponding support; Figure 11 It is a cross-sectional view of the beam segment when the stirrups in the first stirrup encryption zone in the high-level beam segment of Embodiment 2 of the concrete folded beam structure with partially embedded steel skeleton of the present invention are four-leg stirrups; Figure 12 The beam moment diagram of the concrete folded beam structure with partially built-in steel skeleton according to the present invention. Specific embodiments

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the embodiments should not be construed as limiting the present invention.

[0021] The present invention can, to a certain extent, make up for the deficiencies of traditional concrete folded beams with steel skeletons, and provides a new type of large-span concrete folded beam with partially built-in steel skeletons and a reinforcement structure, aiming to achieve a balance between structural performance and economic benefits by optimizing the steel skeleton configuration and reinforcement design. Among them, the folded beam structure is composed of components such as concrete beams, steel skeletons, and longitudinal steel bars.

[0022] See Figure 1 , the concrete folded beam structure with partially built-in steel skeletons according to the present invention includes a concrete folded beam 1 composed of a high-level beam section 1.1, a vertical beam section 1.2, and a low-level beam section 1.3, and supports respectively located at both ends of the concrete folded beam 1.

[0023] Embodiment 1 See Figures 2 to 3 , a high-level beam section steel skeleton 2 arranged along the axial direction thereof is built in the high-level beam section 1.1, a vertical beam section steel skeleton 3 is built in the vertical beam section 1.2, a low-level beam section steel skeleton 4 arranged along the axial direction thereof is built in the low-level beam section 1.3, and the high-level beam section steel skeleton 2, the vertical beam section steel skeleton 3, and the low-level beam section steel skeleton 4 are connected end to end. In one or more embodiments, the high-level beam section steel skeleton 2, the vertical beam section steel skeleton 3, and the low-level beam section steel skeleton 4 are I-beams; the sum of the axial lengths of the high-level beam section steel skeleton 2 and the low-level beam section steel skeleton 4 is shorter than the sum of the axial lengths of the high-level beam section 1.1 and the low-level beam section 1.3, and an integrally folded steel bar mesh is arranged outside the high-level beam section steel skeleton 2, the vertical beam section steel skeleton 3, and the low-level beam section steel skeleton 4, and both ends of the folded steel bar mesh are respectively connected to the corresponding supports.

[0024] The top and bottom of the high-level beam section steel skeleton 2 and the low-level beam section steel skeleton 4, as well as both sides of the vertical beam section steel skeleton 3, are flange plates. The flange plates at the top of the high-level beam section steel skeleton 2 and the low-level beam section steel skeleton 4 are connected to the flange plate on one side of the vertical beam section steel skeleton 3, and the flange plates at the bottom of the high-level beam section steel skeleton 2 and the low-level beam section steel skeleton 4 are connected to the flange plate on the other side of the vertical beam section steel skeleton 3. Above the flange plates at the top of the high-level beam section steel skeleton 2 and the low-level beam section steel skeleton 4, multiple upper longitudinal steel bars 5 arranged along the axial direction of the flange plate and within the width of the flange plate are evenly distributed. Below the flange plates at the bottom of the high-level beam section steel skeleton 2 and the low-level beam section steel skeleton 4, multiple lower longitudinal steel bars 6 arranged along the axial direction of the flange plate and within the width of the flange plate are respectively evenly distributed. The upper longitudinal steel bars 5 within the width of the flange plate of the high-level beam section steel skeleton 2 and the lower longitudinal steel bars 6 within the width of the flange plate of the high-level beam section steel skeleton 2 and the low-level beam section steel skeleton 4 all extend into the vertical beam section 1.2.

[0025] At the bottom of the intersection of the high-level beam section steel skeleton 2 and the vertical beam section steel skeleton 3, there is an inclined connecting plate 12. In one or more embodiments, the inclined connecting plate 12 forms an angle of 45° with the horizontal plane. The lower longitudinal steel bars 6 within the width of the flange plate of the high-level beam section steel skeleton 2 are connected to the inclined connecting plate 12 and then extend vertically along the plate surface of the inclined connecting plate 12 into the vertical beam section 1.2 until below the low-level beam section steel skeleton 4 and are bent. The lower longitudinal steel bars 6 within the width of the flange plate of the low-level beam section steel skeleton 4 are bent and extend into the vertical beam section 1.2. The lower longitudinal steel bars 6 within the width of the flange plate of the high-level beam section steel skeleton 2 are welded to the plate surface of the inclined connecting plate 12. The two ends of the inclined connecting plate 12 are respectively a high-level connecting line 14 and a low-level connecting line 15 at the connection with the high-level beam section steel skeleton 2 and the vertical beam section steel skeleton 3. At the position corresponding to the high-level connecting line 14 within the high-level beam section steel skeleton 2, there is a vertically arranged first stiffening plate 13, and at the position corresponding to the low-level connecting line 15 within the vertical beam section steel skeleton 3, there is a horizontally arranged second stiffening plate 13.

[0026] The structure of the concrete folded beam 1 is composed of a high-level beam segment 1.1, a vertical beam segment 1.2 and a low-level beam segment 1.3 to form a zigzag structure. The mechanical properties of the vertical beam segment 1.2 are similar to those of a short column, mainly showing a combined compression and bending stress state. When the vertical beam segment 1.2 is subjected to a vertical load and a lateral force at the same time, a significant shear force distribution is generated in its cross-section. In this concrete folded beam 1 structure, the steel skeleton is only arranged at the vertical beam segment 1.2 or from the vertical beam segment 1.2 to the support with a relatively large bending moment value (this support refers to the intersection of the folded beam and the columns at both ends of the folded beam), and continuous steel skeleton is used to resist the combined stress (bending moment + shear force + axial force) at the turning point of the concrete folded beam 1. At the connection between the bottom of the high-level beam segment 1.1 and the vertical beam segment 1.2, a vertical haunch with an aspect ratio of 1:1 is set (a vertical haunch is usually at the end or support of a beam, and the bearing capacity of the structure is enhanced by locally increasing the height of the beam, that is Figure 2 the concrete structure with an inclined surface connected to the inclined connecting plate 12). The stress concentration is relieved by the gradual change of the cross-section.

[0027] Above the intersection of the vertical beam segment steel skeleton 3 and the low-level beam segment steel skeleton 4, a cross-shaped orthogonal connecting plate 11 is provided. One end of the horizontal plate of the cross-shaped orthogonal connecting plate 11 is connected to the flange plate of the vertical beam segment steel skeleton 3, and one end of the vertical plate of the cross-shaped orthogonal connecting plate 11 is connected to the flange plate at the top of the low-level beam segment steel skeleton 4. The upper longitudinal reinforcement 5 within the width of the flange plate of the high-level beam segment steel skeleton 2 is welded to the vertical plate surface of the cross-shaped orthogonal connecting plate 11 after entering the vertical beam segment 1.2, and the upper longitudinal reinforcement 5 within the width of the flange plate of the low-level beam segment steel skeleton 4 is welded to the horizontal plate surface of the cross-shaped orthogonal connecting plate 11. In one or more embodiments, there is a gap between the bottom end of the upper longitudinal reinforcement 5 within the width of the flange plate of the high-level beam segment steel skeleton 2 and the end of the upper longitudinal reinforcement 5 within the width of the flange plate of the low-level beam segment steel skeleton 4; a third stiffening plate 13 arranged horizontally is provided at the place corresponding to the horizontal plate of the cross-shaped orthogonal connecting plate 11 within the vertical beam segment steel skeleton 3 of the horizontal plate, and a fourth stiffening plate 13 arranged vertically is provided at the place corresponding to the vertical plate of the cross-shaped orthogonal connecting plate 11 within the low-level beam segment steel skeleton 4.

[0028] In the reinforcement structure of the concrete folded beam 1, the stressed longitudinal bars are divided into two parts: within the width range of the steel beam flange plate and outside the width range of the steel beam flange plate. The anchorage of the stressed longitudinal bars at the turning points within the width range of the steel beam flange plate is unfavorable (this is because within the width range of the steel beam flange plate, the bending space available for the stressed longitudinal bars is small, and at this time, the concrete may not be able to effectively fix the steel bars, resulting in easy disconnection during stress). To avoid the problem of increased construction difficulty caused by multiple bends of the steel bars, connection plates are respectively provided at the intersections of the vertical beam section 1.2 with the high-level beam section 1.1 and the low-level beam section 1.3, and the stressed longitudinal bars are welded to the connection plates for anchorage connection. Among them, the upper longitudinal bars 5 within the flange plate width are connected by two orthogonal steel plates, namely the cross-orthogonal connection plate 11, at the intersection of the top of the low-level beam section 1.3 and the vertical beam section 1.2. The lower longitudinal bars 6 within the flange plate width are anchored and connected by a 45° inclined connection plate 12 at the intersection of the bottom of the high-level beam section 1.1 and the vertical beam section 1.2, avoiding construction defects caused by multiple bends. To enhance the structural strength, stiffening plates 13 are provided at the corresponding positions on the opposite side of the flange plate of the cross-orthogonal connection plate 11 and the inclined connection plate 12. The stiffening plates 13 have the same thickness as the corresponding cross-orthogonal connection plate 11 and inclined connection plate 12 but are not connected.

[0029] See Figures 3 to 4 , longitudinal bars 7 outside the flange plate width are provided above the top and below the bottom of the high-level beam section steel beam 2 and the low-level beam section steel beam 4, and on the obliquely outer side of the flange plate of the vertical beam section steel beam 3. The ends of the longitudinal bars 7 outside the flange plate width within the high-level beam section 1.1 and the low-level beam section 1.3 are bent in the extending direction of the vertical beam section 1.2. The two ends of the longitudinal bars 7 outside the flange plate width within the vertical beam section 1.2 are respectively bent in the extending directions of the high-level beam section 1.1 and the low-level beam section 1.3. The high-level beam section 1.1, the vertical beam section 1.2, and the low-level beam section 1.3 are provided with multiple circles of stirrups 9 arranged according to the axial cross-sections of each beam section along their axes. In one or more embodiments, the stirrups 9 are two-leg stirrups, and the diameter of the two-leg stirrups is larger than the diameter of the four-leg stirrups; the upper longitudinal bars 5 within the flange plate width, the lower longitudinal bars 6 within the flange plate width, and the longitudinal bars 7 outside the flange plate width are all connected to the inner sides of the multiple circles of stirrups 9.

[0030] Beam side waist bars 8 are provided between the top and bottom of the high-level beam section 1.1 and the low-level beam section 1.3, and between the longitudinal bars 7 outside the flange plate width on both sides of the vertical beam section 1.2. The ends of the beam side waist bars 8 within the high-level beam section 1.1 and the low-level beam section 1.3 are bent in the extending direction of the vertical beam section 1.2. The two ends of the beam side waist bars 8 within the vertical beam section 1.2 are respectively bent in the extending directions of the high-level beam section 1.1 and the low-level beam section 1.3. The beam side waist bars 8 are all connected to the inner sides of the multiple circles of stirrups 9.

[0031] The concrete folding beam 1 is provided with a plurality of additional oblique steel bars 10. In one or more embodiments, the additional oblique steel bars 10 form an angle of 45° with the horizontal plane. There are four additional oblique steel bars 10, of which two are provided on each side of the high-level beam section steel frame 2, the vertical beam section steel frame 3 and the low-level beam section steel frame 4. The plurality of additional oblique steel bars 10 are arranged from high to low, and both ends pass through the vertical beam section 1.2 and extend into the high-level beam section 1.1 and the low-level beam section 1.3 respectively. The plurality of additional oblique steel bars 10 are symmetrically arranged along the corresponding high-level beam section steel frame 2, the vertical beam section steel frame 3 and the low-level beam section steel frame 4. Figure 5 More than half of the length of the multiple oblique additional steel bars 10 is located between the longitudinal steel bars 7 outside the corresponding flange plate width, and the multiple oblique additional steel bars 10 are connected to the inner side of the stirrups 9 passing through.

[0032] In the concrete folded beam 1, the load-bearing longitudinal reinforcement outside the width of the steel flange plate, the load-bearing longitudinal reinforcement within the high-level beam section 1.1 and the low-level beam section 1.3, are extended into the vertical beam section 1.2 for bend anchoring. The load-bearing longitudinal reinforcement within the vertical beam section 1.2, namely the longitudinal reinforcement 7 and the side beam reinforcement 8, are extended into the high-level beam section 1.1 and the low-level beam section 1.3 for bend anchoring at both ends, forming a closed force transmission path. The bending length of the ends of the longitudinal reinforcement 7 and the side beam reinforcement 8 is no less than 15 times the diameter of the reinforcement. To compensate for the strength loss of the load-bearing longitudinal reinforcement, additional inclined reinforcement 10 with a total cross-sectional area no less than 45° to the total cross-sectional area of the load-bearing longitudinal reinforcement within the width of the steel flange plate, namely the multiple upper longitudinal reinforcements 5 within the width of the flange plate and the multiple lower longitudinal reinforcements 6 within the width of the flange plate, are added on both sides of the high-level beam section 1.1, the vertical beam section 1.2, and the low-level beam section 1.3. The longitudinal reinforcement 7 outside the flange plate width, the beam side waist reinforcement 8 and the inclined additional reinforcement 10 are not connected to the steel frame.

[0033] See also Figure 6 The spacing between the stirrups 9 at the vertical beam segment steel frame 3 and at the connection between the vertical beam segment steel frame 3 and the high-level beam segment steel frame 2, and the vertical beam segment steel frame 3 and the low-level beam segment steel frame 4 in the concrete folded beam 1 is smaller than the spacing between the stirrups 9 at the beam segments other than the connection between the vertical beam segment steel frame 3 and the vertical beam segment steel frame 3 and the high-level beam segment steel frame 2, and the vertical beam segment steel frame 3 and the low-level beam segment steel frame 4 in the concrete folded beam 1. In one or more embodiments, the multiple circles of stirrups 9 at the vertical beam segment steel frame 3 and at the connection between the vertical beam segment steel frame 3 and the high-level beam segment steel frame 2, and the vertical beam segment steel frame 3 and the low-level beam segment steel frame 4 in the concrete folded beam 1 form a first stirrup reinforcement densification area 16, and a second stirrup reinforcement densification area 17 is provided at the connection between the high-level beam segment 1.1 and the low-level beam segment 1.3 and the corresponding support. The axial lengths of the first stirrup reinforcement densification area 16 and the second stirrup reinforcement densification area 17 are both not less than 1.5 times the beam height and not less than 500 mm.

[0034] See also Figures 7 to 8, in one or more embodiments, the axial length of the steel skeleton of the low-level beam section 4 is equal to or less than 1.3 times the axial length of the low-level beam section; the longitudinal steel bars 7 outside the flange plate width and the waist steel bars 8 on the side of the beam in the high-level beam section 1.1 are connected to the corresponding side walls of the bearing. When the end of the steel skeleton of the low-level beam section 4 is connected to the corresponding side wall of the bearing, the longitudinal steel bars 7 outside the flange plate width and the waist steel bars 8 on the side of the beam in the low-level beam section 1.3 are connected to the steel bars of the corresponding side wall of the bearing.

[0035] Embodiment 2 This embodiment is basically the same as Embodiment 1, and the differences are as follows: See Figure 9 , the steel skeleton of the low-level beam section 4 extends along the low-level beam section 1.3 into the corresponding bearing. See Figure 10 , the longitudinal steel bars 7 outside the flange plate width and the waist steel bars 8 on the side of the beam in the low-level beam section 1.3 extend into the corresponding bearing, and the longitudinal steel bars 7 outside the flange plate width and the waist steel bars 8 on the side of the beam in the high-level beam section 1.1 extend into the corresponding bearing.

[0036] Whether the steel skeleton of the horizontal beam section in the folded beam structure extends into the bearing is divided into the following two cases: 1. When the vertical beam section 1.2 is close to the mid-span and the distance from the bearing is large, the mid-span bending moment value is large and the bearing bending moment value is small, then the steel skeletons in both the high-level beam section 1.1 and the low-level beam section 1.3 do not extend into the bearing. See Figures 7 to 8 ; 2. When the distance between the vertical beam section 1.2 and the bearing is small and the bearing bending moment value is large, steel skeletons are arranged along the entire length of the high-level beam section 1.1 and the low-level beam section 1.3 between the vertical beam section 1.2 and the bearing, and the single-sided steel skeleton extends into the bearing. See Figures 9 to 10 .

[0037] The extended length of the steel skeletons in the high-level beam section 1.1 and the low-level beam section 1.3 of the concrete folded beam 1 needs to be determined according to the bending moment diagram of the beam and should envelope the extreme bending moment area. When the positive bending moment in the beam span is large, the steel skeleton lengths in the high-level beam section 1.1 and the low-level beam section 1.3 need to envelope the positive bending moment area; when the negative bending moment value at the bearing is large, the steel skeleton lengths in the high-level beam section 1.1 and the low-level beam section 1.3 need to envelope the negative bending moment area.

[0038] The bending length of the longitudinal steel bars 7 outside the flange plate width and the waist steel bars 8 on the side of the beam is not less than 15 times the diameter of the steel bars.

[0039] See Figure 11 , when the difference between the beam width and the flange plate width of the steel skeleton is not less than 250 mm, the stirrup 9 is a four-leg stirrup; when the stirrup 9 is a four-leg stirrup, the longitudinal steel bars 7 outside the flange plate width, the waist steel bars 8 on the side of the beam and the diagonal additional steel bars 10 are all connected to the outer stirrup of the stirrup 9.

[0040] The total cross-sectional area of the four oblique additional steel bars 10 is not less than the total cross-sectional area of the upper longitudinal steel bars 5 within the width of the multiple flange plates and the total cross-sectional area of the lower longitudinal steel bars 6 within the width of the multiple flange plates; the steel bar diameters of the two upper oblique additional steel bars 10 are the same as the steel bar diameter with the largest diameter among the upper longitudinal steel bars 5 within the width of the flange plate and the longitudinal steel bars 7 outside the width of the flange plate; the steel bar diameters of the two lower oblique additional steel bars 10 are the same as the steel bar diameter with the largest diameter among the lower longitudinal steel bars 6 within the width of the flange plate and the longitudinal steel bars 7 outside the width of the flange plate.

[0041] The upper longitudinal reinforcement 5 within the width of the flange plate is welded to the cross orthogonal connecting plate 11 on both sides, and the lower longitudinal reinforcement 6 within the width of the flange plate of the high-level beam section steel frame 2 is welded to the oblique connecting plate 12 on both sides.

[0042] The high-level beam segment steel frame 2, the vertical beam segment steel frame 3 and the low-level beam segment steel frame 4 are U-shaped steel, wherein the top surface and the bottom surface of the high-level beam segment steel frame 2 and the low-level beam segment steel frame 4 are flange plates respectively, and the side walls of the vertical beam segment steel frame 3 connected to the flange plates of the high-level beam segment steel frame 2 and the low-level beam segment steel frame 4 are flange plates.

[0043] The stirrup reinforcement 9 of the concrete folded beam 1 is constructed identically to that of a conventional horizontal beam in the non-steel section, with a second stirrup reinforcement zone 17 at the support, no less than 1.5 times the beam height and no less than 500mm in length. Unlike conventional beams, stirrup reinforcement zones are also required at the mid-span of the steel folded beam, i.e., at the vertical beam section steel 3, and at the junctions of the vertical beam section steel 3 with the high-level beam section steel 2, and the vertical beam section steel 3 with the low-level beam section steel 4. A first stirrup reinforcement zone 16 extends from the turning point of the vertical beam section steel 3 toward the support, no less than 1.5 times the beam height and no less than 500mm in length. If necessary, stirrup reinforcement 9 in the steel-framed beam section must be reinforced along its entire length. When the difference between the width of the steel frame flange and the cross-sectional width of the concrete folded beam 1 is small and the number of stirrups 9 cannot be increased, the diameter of the stirrups 9 can be increased to ensure that the area of the stirrups 9 meets the requirements of the densified area (in the embodiment, according to the calculation results and the minimum stirrup ratio, it is necessary to set a two-legged stirrup with a cross-sectional area of not less than 8@100(4) and finally 12@100(2) was selected. When promoting and applying it, it is only necessary to meet the calculated reinforcement cross-sectional area). Figure 11 Generally, when the beam width exceeds 400mm, four-legged stirrups are required. In the embodiment, there is a 300mm wide steel frame in the 500mm wide concrete folding beam 1. Setting four-legged stirrups will result in the distance between the stirrups 9 being too small, making construction difficult. Therefore, the diameter of the stirrups 9 needs to be increased (from 8mm to 12mm) and set as two-legged stirrups.

[0044] The present invention adopts a concrete folded beam structure with partially built-in steel girders. The concrete folded beam structure includes a concrete folded beam 1, a high-level beam section steel girder 2, a vertical beam section steel girder 3, and a low-level beam section steel girder 4, upper longitudinal reinforcement bars 5 within the flange width, lower longitudinal reinforcement bars 6 within the flange width, longitudinal reinforcement bars 7 outside the flange width, beam side waist reinforcement bars 8, stirrups 9, diagonal additional reinforcement bars 10, a cross-shaped orthogonal connecting plate 11, a diagonal connecting plate 12, and a stiffening plate 13. The lengths of the high-level beam section steel girder 2 and the low-level beam section steel girder 4 need to be determined and valued according to the bending moment diagram of the concrete folded beam 1. The upper longitudinal reinforcement bars 5 within the flange width in the vertical beam section 1.2 and the upper longitudinal reinforcement bars 5 within the flange width in the low-level beam section 1.3 are not connected but left with a gap and thus interrupted by the steel girder. To ensure their strength, the upper longitudinal reinforcement bars 5 within the flange width are double-sided welded to the cross-shaped orthogonal connecting plate 11, and the ends of the cross-shaped orthogonal connecting plate 11 are respectively welded to the vertical beam section steel girder 3 and the low-level beam section steel girder 4 and stiffening plates 13 are provided to strengthen the connection. The lower longitudinal reinforcement bars 6 within the flange width of the high-level beam section steel girder 2 are bent and double-sided welded to the diagonal connecting plate 12, and the diagonal connecting plate 12 is respectively welded to the high-level beam section steel girder 2 and the vertical beam section steel girder 3 and stiffening plates 13 are provided to strengthen the connection. The longitudinal reinforcement bars 7 outside the flange width and the beam side waist reinforcement bars 8 are Figure 10 bent and anchored. When necessary, the stirrups 9 are encrypted throughout the length of the beam section with steel girders. The diagonal additional reinforcement bars 10 are respectively provided on both sides of the concrete folded beam 1, as Figure 5 shown. The diameter of the upper diagonal additional reinforcement bar 10 is the same as the diameter of the largest-diameter steel bar among the upper longitudinal reinforcement bars 5 within the flange width and the longitudinal reinforcement bars 7 outside the flange width, and the diameter of the lower diagonal additional reinforcement bar 10 is the same as the diameter of the largest-diameter steel bar among the lower longitudinal reinforcement bars 6 within the flange width and the longitudinal reinforcement bars 7 outside the flange width; and it is necessary to ensure that the total cross-sectional area of the diagonal additional reinforcement bars 10 is respectively greater than the total cross-sectional area of multiple upper longitudinal reinforcement bars 5 within the flange width and the total cross-sectional area of multiple lower longitudinal reinforcement bars 6 within the flange width. Thus, a safe and reliable steel girder folded beam structure is formed, which is applicable to large-span vertical folded beams. This steel girder folded beam structure reduces material waste, simplifies the beam-column joints, and improves the utilization rate of structural members.

[0045] The technical principle and key points of the present invention: 1. The present invention first discloses a concrete vertical folded beam solution with partially built-in steel girders. The key lies in setting steel girders only in the turning sections with complex forces, and only normal reinforcement bars are configured in the remaining beam sections, which can achieve the purpose of saving materials and simplifying the beam-column joints.

[0046] 2. For the turning section of the folded beam with partially built-in steel girders, the present invention discloses comprehensive and specific reinforcement measures: vertical haunching, setting connecting plates for steel bar connection, setting diagonal additional reinforcement bars 10, and stirrup 9 encryption.

[0047] 3. Based on the flexible value-taking of the beam moment diagram, the present invention proposes the basis for the value-taking of the length of the built-in steel skeleton.

[0048] The technology closest to the present invention is the concrete vertical bent beam structure with a full-length built-in steel skeleton. Compared with the technical solution of the full-length built-in steel skeleton, the present invention uses less steel to meet the bearing capacity requirements, can save materials, and improve the utilization rate of structural members. The full-length setting of the steel skeleton in the beam section will complicate the beam-column joints. In the present invention, the addition of steel skeletons in the columns is avoided or reduced, achieving the purpose of simplifying the beam-column joints, thereby reducing the construction difficulty. At the same time, in the bent beam section of the present invention, comprehensive reinforcement measures such as adding vertical haunches, setting connecting plates to connect steel bars, setting diagonal additional steel bars 10 and densifying stirrups 9 are added to make the structure safer and more reliable.

[0049] The present invention has been proven feasible through structural calculation software. In the commonly used structural calculation software YJK, a large-span vertical bent beam structure model with a partial built-in steel skeleton in a single span is established, and the beam moment diagram is calculated. See Figure 12 . It can be analyzed from the moment diagram that the moment at the support is small, and the moment value at the mid-span bent section is large. It is only necessary to set the steel skeleton in the mid-span bent section. In this embodiment, in the construction drawing stage of a certain museum structure, the concrete vertical bent beam with a partial built-in steel skeleton described in this scheme is used as the roof frame beam in the column-free large space under the variable-height roof. The span of this beam is 19m, and the height of the vertical bent section is 1.5m to 3.6m.

[0050] The advantages of the concrete bent beam structure with a partial built-in steel skeleton of the present invention are as follows: Segmental arrangement of steel skeletons: Based on the moment distribution characteristics, the steel skeletons are only arranged in the vertically stressed beam section 1.2 with complex stress or the extended area of the support with a large moment, significantly reducing the steel consumption; Simplification of joint construction: Avoid the complex connection of the traditional full-length steel skeleton and the column joint, reduce the requirement for embedded steel skeletons in the column, eliminate the spatial interference problem between steel bars and steel skeletons, and improve the construction convenience.

[0051] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these changes and modifications.

[0052] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

Claims

1. A concrete folded beam structure with partially built-in steel bones, comprising a concrete folded beam (1) composed of a high-level beam section (1.1), a vertical beam section (1.2) and a low-level beam section (1.3), and supports respectively located at both ends of the concrete folded beam (1). The high-level beam section (1.1) is built-in with a high-level beam section steel bone (2) arranged along its axial direction. The vertical beam section (1.2) is built-in with a vertical beam section steel bone (3). The low-level beam section (1.3) is built-in with a low-level beam section steel bone (4) arranged along its axial direction. The high-level beam section steel bone (2), the vertical beam section steel bone (3) and the low-level beam section steel bone (4) are connected end to end. It is characterized in that: The sum of the axial lengths of the high-level beam section steel skeleton (2) and the low-level beam section steel skeleton (4) is shorter than the sum of the axial lengths of the high-level beam section (1.1) and the low-level beam section (1.3). A reinforcing steel mesh integrally in a folded shape is provided on the outer sides of the high-level beam section steel skeleton (2), the vertical beam section steel skeleton (3), and the low-level beam section steel skeleton (4), and the two ends of the folded reinforcing steel mesh are respectively connected to the corresponding supports.

2. The concrete folded beam structure with partially built-in steel bones according to claim 1, characterized in that: The top and bottom of the high-level beam section steel skeleton (2) and the low-level beam section steel skeleton (4), and both sides of the vertical beam section steel skeleton (3) are flange plates. The flange plate at the top of the high-level beam section steel skeleton (2) and the low-level beam section steel skeleton (4) is connected to the flange plate on one side of the vertical beam section steel skeleton (3), and the flange plate at the bottom of the high-level beam section steel skeleton (2) and the low-level beam section steel skeleton (4) is connected to the flange plate on the other side of the vertical beam section steel skeleton (3). Above the flange plates at the top of the high-level beam section steel skeleton (2) and the low-level beam section steel skeleton (4), multiple upper longitudinal reinforcing bars (5) arranged axially along the flange plates and within the width of the flange plates are evenly distributed. Below the flange plates at the bottom of the high-level beam section steel skeleton (2) and the low-level beam section steel skeleton (4), multiple lower longitudinal reinforcing bars (6) arranged axially along the flange plates and within the width of the flange plates are respectively evenly distributed. The upper longitudinal reinforcing bars (5) within the width of the flange plates of the high-level beam section steel skeleton (2), and the lower longitudinal reinforcing bars (6) within the width of the flange plates of the high-level beam section steel skeleton (2) and the low-level beam section steel skeleton (4) all extend into the vertical beam section (1.2).

3. The concrete folded beam structure with partially built-in steel bones according to claim 2, characterized in that: An inclined connecting plate (12) is provided at the bottom of the intersection of the high-level beam section steel skeleton (2) and the vertical beam section steel skeleton (3). The lower longitudinal reinforcing bars (6) within the width of the flange plates of the high-level beam section steel skeleton (2) are connected to the inclined connecting plate (12) and then extend vertically along the plate surface of the inclined connecting plate (12) into the vertical beam section (1.2) until below the low-level beam section steel skeleton (4) and are bent. The lower longitudinal reinforcing bars (6) within the width of the flange plates of the low-level beam section steel skeleton (4) are bent and extend into the vertical beam section (1.2). The lower longitudinal reinforcing bars (6) within the width of the flange plates of the high-level beam section steel skeleton (2) are welded to the plate surface of the inclined connecting plate (12). The two ends of the inclined connecting plate (12) are respectively a high-level connecting line (14) and a low-level connecting line (15) at the connection parts with the high-level beam section steel skeleton (2) and the vertical beam section steel skeleton (3). A first stiffening plate (13) vertically arranged is provided at the corresponding position in the high-level beam section steel skeleton (2) corresponding to the high-level connecting line (14), and a second stiffening plate (13) horizontally arranged is provided at the corresponding position in the vertical beam section steel skeleton (3) corresponding to the low-level connecting line (15).

4. The concrete folded beam structure with partially built-in steel skeleton according to claim 3, characterized in that: Above the intersection of the vertical beam steel section (3) and the low-level beam steel section (4), there is a cross-shaped orthogonal connecting plate (11). One end of the horizontal plate of the cross-shaped orthogonal connecting plate (11) is connected to the flange plate of the vertical beam steel section (3), and one end of the vertical plate of the cross-shaped orthogonal connecting plate (11) is connected to the flange plate at the top of the low-level beam steel section (4). The upper longitudinal reinforcement bars (5) within the width of the flange plate of the high-level beam steel section (2) enter the vertical beam section (1.2) and are welded to the vertical plate surface of the cross-shaped orthogonal connecting plate (11). The upper longitudinal reinforcement bars (5) within the width of the flange plate of the low-level beam steel section (4) are welded to the horizontal plate surface of the cross-shaped orthogonal connecting plate (11). At the place corresponding to the horizontal plate of the cross-shaped orthogonal connecting plate (11) within the vertical beam steel section (3) of the horizontal plate, there is a horizontally arranged third stiffening plate (13). At the place corresponding to the vertical plate of the cross-shaped orthogonal connecting plate (11) within the low-level beam steel section (4), there is a vertically arranged fourth stiffening plate (13).

5. The concrete folded beam structure with partially built-in steel bones according to claim 4, characterized in that: Above the top and below the bottom of the high-level beam steel section (2) and the low-level beam steel section (4), and on the outer diagonal sides of the flange plates of the vertical beam steel section (3), there are longitudinal reinforcement bars (7) outside the width of the flange plate. The ends of the longitudinal reinforcement bars (7) outside the width of the flange plate within the high-level beam section (1.1) and the low-level beam section (1.3) are bent in the extending direction of the vertical beam section (1.2). The two ends of the longitudinal reinforcement bars (7) outside the width of the flange plate within the vertical beam section (1.2) are respectively bent in the extending directions of the high-level beam section (1.1) and the low-level beam section (1.3). The high-level beam section (1.1), the vertical beam section (1.2), and the low-level beam section (1.3) are provided with multiple circles of stirrups (9) arranged according to the axial cross-sections of each beam section along their axes. The upper longitudinal reinforcement bars (5), the lower longitudinal reinforcement bars (6) within the width of the flange plate, and the longitudinal reinforcement bars (7) outside the width of the flange plate are all connected to the inner sides of the multiple circles of stirrups (9).

6. The concrete folded beam structure with partially built-in steel bones according to claim 5, characterized in that: Between the top and bottom of the high-level beam section (1.1) and the low-level beam section (1.3), and between the longitudinal reinforcement bars (7) outside the width of the flange plate on both sides of the vertical beam section (1.2), there are waist reinforcement bars (8) on the side of the beam. The ends of the waist reinforcement bars (8) within the high-level beam section (1.1) and the low-level beam section (1.3) are bent in the extending direction of the vertical beam section (1.2). The two ends of the waist reinforcement bars (8) within the vertical beam section (1.2) are respectively bent in the extending directions of the high-level beam section (1.1) and the low-level beam section (1.3). The waist reinforcement bars (8) are all connected to the inner sides of the multiple circles of stirrups (9).

7. The concrete folded beam structure with partially built-in steel bones according to claim 6, characterized in that: The concrete bent beam (1) is provided with a plurality of inclined additional steel bars (10). The plurality of inclined additional steel bars (10) are arranged from high to low, and both ends pass through the vertical beam section (1.2) and extend into the high-level beam section (1.1) and the low-level beam section (1.3) respectively. The plurality of inclined additional steel bars (10) are symmetrically arranged on both sides of the corresponding high-level beam section steel skeleton (2), vertical beam section steel skeleton (3) and low-level beam section steel skeleton (4). More than half of the length of the plurality of inclined additional steel bars (10) is located between the longitudinal steel bars (7) outside the width of the corresponding flange plate. The plurality of inclined additional steel bars (10) are connected to the inner side of the passing stirrups (9).

8. The concrete folded beam structure with partially built-in steel skeleton according to claim 7, characterized in that: There is a gap between the bottom end of the upper longitudinal steel bar (5) within the flange plate width of the high-level beam section steel skeleton (2) and the end of the upper longitudinal steel bar (5) within the flange plate width of the low-level beam section steel skeleton (4).

9. The concrete folded beam structure with partially built-in steel skeleton according to claim 8, characterized in that: The spacing between the stirrups (9) at the vertical beam section steel skeleton (3) in the concrete bent beam (1) and at the joints of the vertical beam section steel skeleton (3) with the high-level beam section steel skeleton (2) and the vertical beam section steel skeleton (3) with the low-level beam section steel skeleton (4) is smaller than the spacing between the stirrups (9) at the beam sections outside the vertical beam section steel skeleton (3) and at the joints of the vertical beam section steel skeleton (3) with the high-level beam section steel skeleton (2) and the vertical beam section steel skeleton (3) with the low-level beam section steel skeleton (4) in the concrete bent beam (1).

10. The concrete folded beam structure with partially built-in steel bones according to claim 9, characterized in that: The axial length of the low-level beam section steel skeleton (4) is equal to or less than the axial length of the low-level beam section (1.3), or the low-level beam section steel skeleton (4) extends along the low-level beam section (1.3) into the corresponding support. The bending length of the longitudinal steel bars (7) and the beam side waist bars (8) outside the flange plate width is not less than 15 times the diameter of the steel bars. Both the inclined connecting plate (12) and the inclined additional steel bars (10) form an angle of 45° with the horizontal plane. The stirrups (9) are two-leg stirrups or four-leg stirrups. When the stirrups (9) are four-leg stirrups, the longitudinal steel bars (7), beam side waist bars (8) and inclined additional steel bars (10) outside the flange plate width are all connected to the outer stirrups of the stirrups (9). When the stirrups (9) are two-leg stirrups, the diameter of the two-leg stirrups is larger than the diameter of the four-leg stirrups. The longitudinal steel bars (7) and the beam side waist bars (8) outside the flange plate width in the high-level beam section (1.1) are connected to the side wall of the corresponding support or extend into the support. When the end of the low-level beam section steel skeleton (4) is connected to the side wall of the corresponding support, the longitudinal steel bars (7) and the beam side waist bars (8) outside the flange plate width in the low-level beam section (1.3) are connected to the steel bars on the side wall of the corresponding support. When the low-level beam section steel skeleton (4) extends along the low-level beam section (1.3) into the corresponding support, the longitudinal steel bars (7) and the beam side waist bars (8) in the low-level beam section (1.3) extend into the corresponding support. In the concrete folded beam (1), multiple hoop stirrups (9) located at the steel skeleton (3) of the vertical beam segment and at the joints of the steel skeleton (3) of the vertical beam segment with the high-level beam segment steel skeleton (2) and the steel skeleton (3) of the vertical beam segment with the low-level beam segment steel skeleton (4) form a first hoop stirrup reinforcement area (16). At the joints of the high-level beam segment (1.1) and the low-level beam segment (1.3) with the corresponding supports, a second hoop stirrup reinforcement area (17) is provided. The axial lengths of both the first hoop stirrup reinforcement area (16) and the second hoop stirrup reinforcement area (17) are not less than 1.5 times the beam height and not less than 500 mm. There are four diagonal additional steel bars (10). Among them, there are two on each side of the high-level beam segment steel skeleton (2), the vertical beam segment steel skeleton (3), and the low-level beam segment steel skeleton (4). The total cross-sectional areas of the four diagonal additional steel bars (10) are respectively not less than the total cross-sectional area of the upper longitudinal steel bars (5) within the width of multiple flange plates and the total cross-sectional area of the lower longitudinal steel bars (6) within the width of multiple flange plates. The diameters of the two upper diagonal additional steel bars (10) are the same as the diameter of the thickest steel bar among the upper longitudinal steel bars (5) within the width of the flange plate and the longitudinal steel bars (7) outside the width of the flange plate. The diameters of the two lower diagonal additional steel bars (10) are the same as the diameter of the thickest steel bar among the lower longitudinal steel bars (6) within the width of the flange plate and the longitudinal steel bars (7) outside the width of the flange plate. The upper longitudinal steel bars (5) within the width of the flange plate are double-sided welded to the cross-shaped orthogonal connecting plate (11). The lower longitudinal steel bars (6) within the width of the flange plate of the high-level beam segment steel skeleton (2) are double-sided welded to the surface of the diagonal connecting plate (12). The high-level beam segment steel skeleton (2), the vertical beam segment steel skeleton (3), and the low-level beam segment steel skeleton (4) are I-beams or box-section steel. When the high-level beam segment steel skeleton (2), the vertical beam segment steel skeleton (3), and the low-level beam segment steel skeleton (4) are box-section steel, the top and bottom surfaces of the high-level beam segment steel skeleton (2) and the low-level beam segment steel skeleton (4) are flange plates respectively, and the side walls of the vertical beam segment steel skeleton (3) connected to the flange plates of the high-level beam segment steel skeleton (2) and the low-level beam segment steel skeleton (4) are flange plates.

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