A composite steel beam and construction method thereof

Abstract

The present application discloses a composite steel beam and a construction method thereof, which relates to the field of building structure design and construction, and comprises an energy-absorbing section and a composite section; the energy-absorbing section is directly connected to the frame column, the composite section is between the energy-absorbing sections, and the upper planes of the composite section and the two energy-absorbing sections are located in the same plane; the energy-absorbing section comprises an I-beam and a steel truss floor deck fixedly connected to the upper end of the I-beam, and the two energy-absorbing sections have the same structure and are equal in length; the composite section comprises a steel truss floor deck and a U-shaped steel beam, the U-shaped steel beam is located below the steel truss floor deck, the steel truss floor deck corresponding to the energy-absorbing section and the steel truss floor deck corresponding to the composite section are integrated, an auxiliary steel truss is arranged inside the U-shaped steel beam, and the inside of the U-shaped steel beam is cast as one with the inside of the steel truss floor deck; the new composite beam of the present application has better rigidity and bearing capacity, and has a low cost; and the construction is also relatively convenient.

Description

Technical Field

[0001] The present application relates to the field of building structure design and construction, and in particular to a composite steel beam and a construction method thereof. Background Art

[0002] In my country's industrial and civil buildings, reinforced concrete structures are widely used due to their wide range of raw materials, mature technology and low cost. However, with the increase in building height and earthquake resistance requirements, as well as the increasing requirements of modern buildings for storey height, large span and large space, the application of reinforced concrete structures has been subject to more restrictions.

[0003] Steel structure buildings use steel plates or steel to replace reinforced concrete, which has higher strength and better earthquake resistance. Since the components can be factory-made and installed on-site, the construction period is greatly reduced. In addition, steel can be reused, which can greatly reduce the construction period and is more environmentally friendly. Therefore, it is widely used in countries around the world and applied to industrial and civil buildings.

[0004] However, under wind loads or earthquakes, compared with concrete structures, although steel beams have very good ductility and energy absorption capacity, they are insufficient in stiffness and have higher costs. Summary of the invention

[0005] The embodiment of the present invention solves the problem that the steel beams in the prior art are insufficiently rigid and have a relatively high construction cost compared to concrete beams by providing a composite steel beam and a construction method thereof, thereby achieving a new composite beam having better rigidity, with the inner concrete and the floor slab concrete cast in one step, convenient construction, better composite performance and low cost.

[0006] In a first aspect, an embodiment of the present invention provides a composite steel beam, comprising an energy dissipation section and a composite section;

[0007] The energy absorbing section is directly connected to the frame column, and there is a combined section between the energy absorbing sections, and the upper planes of the combined section and the two energy absorbing sections are located in the same plane;

[0008] The energy absorbing section comprises an I-beam and a steel truss floor deck fixedly connected to the upper end of the I-beam, and the two energy absorbing sections have the same structure and the same length;

[0009] The combined section includes the steel truss floor deck and a U-shaped steel beam, the U-shaped steel beam is located below the steel truss floor deck, the steel truss floor deck corresponding to the energy absorption section and the steel truss floor deck corresponding to the combined section are integrated, an auxiliary steel truss is provided inside the U-shaped steel beam, and the inside of the U-shaped steel beam is cast as one with the inside of the steel truss floor deck.

[0010] In combination with the first aspect, in a possible implementation, the I-beam includes an upper flange plate, a web plate and a lower flange plate, the width of the upper flange plate is greater than the width of the lower flange plate, and the upper flange plate is fixed to the steel truss floor deck.

[0011] In combination with the first aspect, in a possible implementation, the energy-absorbing section and the combined section are connected via a head plate.

[0012] In combination with the first aspect, in a possible implementation, the U-shaped steel beam includes a composite beam web and a composite beam bottom plate; two composite beam webs and one composite beam bottom plate form a U-shaped steel beam, and the composite beam bottom plate is perpendicular to the composite beam web;

[0013] The connection part between the U-shaped steel beam and the steel bar truss floor deck is divided into a first connection structure, a second connection structure, a third connection structure and a fourth connection structure;

[0014] The first connection structure, the second connection structure and the third connection structure all include U-shaped steel beam flange plates; the U-shaped steel beam flange plates are located at the connection between the two free ends of the U-shaped steel beam and the steel truss floor deck, and the U-shaped steel beam flange plates are integrated with the U-shaped steel beam;

[0015] In the first connection structure, the U-shaped steel beam flange plate extends both into the inside of the U-shaped steel beam opening and out of the U-shaped steel beam opening at the upper end of the U-shaped steel beam; in the second connection structure, the U-shaped steel beam flange plate extends into the inside of the U-shaped steel beam opening at the upper end of the U-shaped steel beam; in the third connection structure, the U-shaped steel beam flange plate extends out of the U-shaped steel beam opening at the upper end of the U-shaped steel beam; the upper end of the U-shaped steel beam corresponding to the fourth connection structure is directly perpendicular to the steel truss floor deck.

[0016] In combination with the first aspect, in a possible implementation, the auxiliary steel truss is an X-shaped steel truss, and the X-shaped steel truss includes a first auxiliary truss and a second auxiliary truss, and the free ends of the first auxiliary truss and the second auxiliary truss are both provided with vertical fixed ends, and the vertical fixed ends are in the same direction as the web of the composite beam and are pressed against the inner wall of the web of the composite beam and are welded to the inner wall.

[0017] In combination with the first aspect, in a possible implementation manner, the upper plane of the vertical fixed end is located at the connection between the web plate of the composite beam and the flange plate of the U-shaped steel beam.

[0018] In combination with the first aspect, in a possible implementation, when the composite steel beam is used as a frame beam, the center distance from the energy absorption section connecting the composite section to the frame column is selected as a larger value of 1.5H and L / 8; when the composite steel beam is used as a secondary beam, the length of the energy absorption section is designed to be H; wherein H represents the height of the energy absorption section steel beam, and L represents the horizontal distance between the center points of the two frame columns or the total length of the composite beam.

[0019] In combination with the first aspect, in a possible implementation manner, the calculation formula of the bending bearing capacity of the combined segment is as follows:

[0020]

[0021]

[0022] M is the bending bearing capacity of the composite beam segment (kN.m);

[0023] f is the design value of steel bending strength (MPa);

[0024] A is the flange plate area of ​​the U-shaped steel beam (mm2);

[0025] b is the width of the rectangular section (mm);

[0026] h 0 is the effective height of the section (mm);

[0027] f c is the design value of concrete compressive strength (MPa).

[0028] In a second aspect, an embodiment of the present invention provides a construction method of a composite steel beam, and the construction of the composite steel beam comprises the following steps:

[0029] The I-beam of the energy-absorbing beam section, the U-shaped steel beam of the combined section and the auxiliary steel bar truss are processed and formed at one time in the factory and welded and assembled into a combined steel beam; the combined steel beam is connected to the frame columns on both sides;

[0030] The steel bar truss floor deck is laid on the I-beam and the U-shaped steel beam, and is cast at one time inside the steel bar truss floor deck and the U-shaped steel beam.

[0031] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0032] The embodiment of the present invention adopts two energy-absorbing sections and a combined section installed between two frame columns, and the two ends of the combined section are connected to a frame column through an energy-absorbing section respectively; and the upper planes of the combined section and the two energy-absorbing sections are located in the same plane, the energy-absorbing section includes an I-beam and a steel truss floor deck fixedly connected to the upper end of the I-beam, and the two energy-absorbing sections have the same structure and equal length; the combined section includes a steel truss floor deck and a U-shaped steel beam, the U-shaped steel beam is fixed under the steel truss floor deck, the steel truss floor deck corresponding to the energy-absorbing section and the steel truss floor deck corresponding to the combined section are integrated, an auxiliary steel truss is arranged inside the U-shaped steel beam, and the inside of the U-shaped steel beam is cast into one with the inside of the steel truss floor deck; firstly, the two energy-absorbing sections are connected to the frame columns, and the strength requirements of the frame columns are relatively high. When an earthquake disaster occurs, the surfaces of the combined beam section and the energy-absorbing section are both provided with steel truss floor decks, and the columns, I-beams, U-shaped steel beams and steel truss floor decks ensure the anti-bearing capacity of the overall structure, and the bearing capacity of the energy-absorbing section connected to the frame column The U-shaped steel beam has a certain tensile strength, and the combined section is cast in situ using the U-shaped steel beam and the steel truss floor slab, which further strengthens its shear bearing capacity. The auxiliary steel truss inside the U-shaped steel beam can ensure that the steel beam of the combined section does not deform during the pouring of concrete, and further ensures the shear bearing capacity. The steel material of the energy dissipation section and the combined section has a strong tensile strength, which effectively prevents the combined section and its energy dissipation section from undergoing large buckling. The embodiment of the present invention has better rigidity, and the inner concrete and the floor slab concrete are cast in one time, which is convenient for construction, better combined performance, and low cost. At the same time, the present invention also has better building performance (sound insulation, comfort), and compared with concrete beams, it can be free of formwork and has better energy dissipation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments of the present invention or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A front view of a composite steel beam provided by an embodiment of the present invention;

[0035] Figure 2 A cross-sectional view of a steel beam section of a composite steel beam provided by an embodiment of the present invention;

[0036] Figure 3A cross-sectional view of a first connection structure of a composite steel beam composite section provided in an embodiment of the present invention;

[0037] Figure 4 A cross-sectional view of a second connection structure of a composite steel beam composite section provided in an embodiment of the present invention;

[0038] Figure 5 A cross-sectional view of a third connection structure of a composite steel beam composite section provided in an embodiment of the present invention;

[0039] Figure 6 A cross-sectional view of a third connection structure of a composite steel beam composite section provided in an embodiment of the present invention;

[0040] Figure numerals: 1-energy absorption section; 11-I-beam; 111-web; 112-upper flange plate; 113-lower flange plate; 12-steel truss floor deck; 2-U-shaped steel beam; 21-composite beam web; 22-first auxiliary truss; 23-second auxiliary truss; 24-bolt; 25-steel truss; 26-U-shaped steel beam flange plate; 27-composite beam bottom plate; 3-frame column; 4-composite section. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the description of the embodiments of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present invention. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to the specific circumstances.

[0043] Reference Figure 1-6As shown, an embodiment of the present invention discloses a composite steel beam, comprising an energy dissipation section 1 and a composite section 4;

[0044] The energy absorbing section is directly connected to the frame column, and the energy absorbing sections are provided with a combination section 4, and the upper planes of the combination section 4 and the two energy absorbing sections 1 are located in the same plane;

[0045] The energy absorbing section 1 comprises an I-beam 11 and a steel truss floor deck 12 fixedly connected to the upper end of the I-beam 11. The two energy absorbing sections 1 have the same structure and the same length.

[0046] The combined section 4 includes a steel truss floor deck 12 and a U-shaped steel beam 2. The U-shaped steel beam 2 is located below the steel truss floor deck 12. The steel truss floor deck 12 corresponding to the energy dissipation section 1 and the steel truss floor deck 12 corresponding to the combined section 4 are integrated. An auxiliary steel truss is provided inside the U-shaped steel beam 2, and the inside of the U-shaped steel beam 2 is cast as one with the inside of the steel truss floor deck 12.

[0047] Through the above scheme, first, after the U-shaped steel beam 2 and the steel truss floor deck 12 are connected, concrete is poured inside, so that the U-shaped steel beam 2 and the steel truss floor deck 12 work together to give play to the mechanical properties of the two. The U-shaped steel beam 2 bears tension and vertical shear force, and the steel truss floor deck 12 bears pressure. The two work together to enhance the strength and rigidity of the combined section 4. The frame column 3 is connected to the combined section 4 through the energy absorption section 1. The energy absorption section 1 is also a steel beam section with good ductility and bending resistance. When an earthquake occurs, the energy absorption section 1 transmits the residual energy of the earthquake to the combined section 4, and the upper part of the I-beam 11 of the combined section 4 is connected to the upper part of the U-shaped steel beam 2 and The lower part of the I-beam 11 of the combined section 4 is connected and fixed to the lower part of the U-shaped steel beam 2; firstly, the bending resistance of the connection node between the frame column 3 of the entire combined steel beam and the energy-absorbing section 1 is good, which ensures that the connection node between the frame column 3 and the energy-absorbing section 1 is not easy to bend and break when subjected to vertical and horizontal forces. The U-shaped steel beam 2 of the combined section 4 bears tension and vertical shear force, and the steel truss floor deck 12 bears pressure. The strength and rigidity of the combined section 4 are greatly guaranteed, thereby ensuring that after the energy-absorbing section 1 transmits the residual energy of the earthquake to the combined section 4, the combined section 4 can reduce the occurrence of the problem of combined section 4 breaking due to insufficient load or excessive vertical force.

[0048] Optionally, the I-beam 11 includes an upper flange plate 112, a web plate 111 and a lower flange plate 113. The width of the upper flange plate 112 is greater than that of the lower flange plate 113, and the upper flange plate 112 is fixed to the steel truss floor deck 12. The width of the upper flange plate 112 is greater than that of the lower flange plate 113. The I-beam cross-section of the overall energy-absorbing section 1 presents a trapezoidal structure. The bending resistance near the upper flange plate 112 and the bending resistance near the lower flange plate 113 have gradually changed, with a certain buffer. At the same time, this structure can make the bending bearing capacity above the energy-absorbing section 1 larger. For details, please refer to the following formula. The bending bearing capacity of the energy-absorbing section 1 (steel beam section) can be calculated according to the following formula: M=W x f; M is the bending bearing capacity of the steel beam segment (kN.m); f is the design value of the steel bending strength (MPa); W x is the section modulus of the steel beam segment (mm3); the section modulus is also called the section resistance moment, which is the moment of inertia of the cross section of the bent member around its neutral axis divided by the distance from the neutral axis to the outermost edge of the section.

[0049] Optionally, the energy dissipation section 1 and the combined section 4 are connected by a head plate 5, and the thickness of the head plate 5 can be taken as the height of the steel beam H / 60 ( Figure 1 H) in and is not less than 10mm, ensuring that the strength of the head plate 5 meets the requirements of strength and bearing capacity.

[0050] Optionally, the U-shaped steel beam 2 includes a composite beam web 21 and a composite beam bottom plate 27; the thickness of the composite beam web 21 can be taken as the steel beam height H / 250, and is not less than 3 mm. According to the thickness of the composite beam web 21, combined with other known parameters, the greater the thickness of the composite beam web 21, the greater the shear bearing capacity. The thickness of the composite beam web 21 selected in the embodiment of the present invention can enhance the shear bearing capacity of the composite section 4, while saving the material of the U-shaped steel beam. The U-shaped steel beam cooperates with the cast-in-place concrete to maintain the compressive and shear bearing capacity between the overall U-shaped steel beam and the cast-in-place concrete, and no template is required. The shear bearing capacity of the specific composite section 4 can be calculated according to the following formula: V=2h w t w1 f v +0.7β h h 0 bf t

[0051]

[0052] V is the shear bearing capacity of the composite beam segment (kN);

[0053] h w is the web height (mm);

[0054] t w1 is the web thickness (mm);

[0055] f v is the design value of steel shear strength (MPa);

[0056] h 0 is the effective height of the section (mm);

[0057] b is the width of the rectangular section (mm);

[0058] f t is the design value of concrete tensile strength (MPa);

[0059] β h is the cross-section height influence coefficient.

[0060] Two composite beam webs 21 and a composite beam bottom plate 27 form a U-shaped steel beam 2, and the composite beam bottom plate 27 is perpendicular to the composite beam web 21; the connection portion between the U-shaped steel beam 2 and the steel truss floor deck 12 is divided into a first connection structure, a second connection structure, a third connection structure and a fourth connection structure;

[0061] The first connection structure, the second connection structure and the third connection structure all include a U-shaped steel beam flange plate 26; the U-shaped steel beam flange plate 26 is located at the connection between the two free ends of the U-shaped steel beam 2 and the steel truss floor deck 12, and the U-shaped steel beam flange plate 26 is integrated with the U-shaped steel beam 2;

[0062] In the first connection structure, the U-shaped steel beam flange plate 26 at the upper end of the U-shaped steel beam 2 extends both toward the inside of the opening of the U-shaped steel beam 2 and toward the outside of the opening of the U-shaped steel beam 2; in the second connection structure, the U-shaped steel beam flange plate 26 at the upper end of the U-shaped steel beam 2 extends toward the inside of the opening of the U-shaped steel beam 2; in the third connection structure, the U-shaped steel beam flange plate 26 at the upper end of the U-shaped steel beam 2 extends toward the outside of the opening of the U-shaped steel beam 2; the upper end of the U-shaped steel beam 2 corresponding to the fourth connection structure is directly perpendicular to the steel truss floor deck 12.

[0063] Through the above scheme, the combined section 4 selects a U-shaped steel beam 2 and a steel truss floor deck 12 for connection. There is a steel beam flange plate 26 at the upper end of the U-shaped steel beam 2. The steel beam flange plate 26 of the U-shaped steel beam 2 is fixedly connected to the steel truss 25 of the steel truss floor deck 12 through bolts 24. The bolts 24 are connected to the middle position of the steel beam flange plate 26 of the steel truss 25; the upper end of the U-shaped steel beam 2 is divided into the above-mentioned first connection structure, second connection structure, third connection structure and fourth connection structure according to the structure of the steel beam flange plate 26 and whether there is a steel beam flange plate 26, and the corresponding structures are type I, type II, type III and type IV respectively; and the bending bearing capacity of these four connection structures is from strong to weak in the order of type I>type II>type III>type IV. ; The calculation of the bending bearing capacity can be calculated by the corresponding formula, but at the same time, when some parameters in the formula are consistent, but the positions are different, the bending capacity of the steel beam flange plate 26 located inside the cast-in-place concrete is greater than that of the steel beam flange plate 26 located outside the cast-in-place concrete, because the steel beam flange plate 26 located inside the cast-in-place concrete is affected by the pressure and bearing capacity of the cast-in-place concrete, and has a stronger bending capacity, so it can be better explained that the bending bearing capacity of these four connection structures is from strong to weak in the order of type I> type II> type III> type IV. Therefore, when the composite steel beam is a frame beam, type I, type II, and type III can be used. When the composite steel beam is a secondary beam, type IV can be used for the secondary beam; the specific calculation formula for the bending bearing capacity of the composite section 4 is as follows:

[0064]

[0065]

[0066] M is the bending bearing capacity of the composite beam segment (kN.m);

[0067] f is the design value of steel bending strength (MPa);

[0068] A is the flange plate area of ​​the U-shaped steel beam (mm2);

[0069] b is the width of the rectangular section (mm);

[0070] h 0 is the effective height of the section (mm);

[0071] f c is the design value of concrete compressive strength (MPa).

[0072] Optionally, the auxiliary steel truss is an X-shaped steel truss, and the diameter can be 6mm, 8mm, 10mm or 12mm; the material is HPB300; the X-shaped steel truss includes a first auxiliary truss 22 and a second auxiliary truss 23, and the free ends of the first auxiliary truss 22 and the second auxiliary truss 23 are both provided with vertical fixed ends, and the vertical fixed ends are in the same direction as the composite beam web 21 and are pressed against the inner wall of the composite beam web 21 and welded to the inner wall. The auxiliary steel truss can enhance the shear bearing capacity and rigidity of the U-shaped steel beam 2, ensure that the U-shaped steel beam of the combined section 4 does not deform during the concrete pouring process, and disperse the pressure of the cast-in-place concrete on the U-shaped steel beam 2. The spacing between the first auxiliary truss 22 and the second auxiliary truss 23 is not greater than 800mm, that is, the cross-sectional width of the U-shaped steel beam 2 is not greater than 800mm. This setting depends on the maximum pressure that the U-shaped steel beam can withstand to protect it from deformation. When the width between the first auxiliary steel frame 22 and the second auxiliary steel frame 23 is large, that is, exceeds a certain degree, the cast-in-place concrete pressure between the first auxiliary truss 22 and the second auxiliary truss 23 is large, which is for the U-shaped steel beam. There is a lot of pressure on the bottom surface, and there is no better way to disperse the pressure, which has a certain impact on the load-bearing capacity. Therefore, choosing the spacing between the first auxiliary truss 22 and the second auxiliary truss 23 to be no more than 800mm can combine the above advantages; and in order to enhance the connectivity between the first auxiliary truss 22 and the second auxiliary truss 23 and the U-shaped steel beam 2, and the ability of the first auxiliary truss 22 and the second auxiliary truss 23 to protect the U-shaped steel beam from deformation, the free ends of the first auxiliary truss 22 and the second auxiliary truss 23 are both provided with vertical fixed ends, and the vertical fixed ends have the effect of supporting and enhancing the integration of the first auxiliary truss 22 and the second auxiliary truss 23 and the U-shaped steel beam 2.

[0073] Optionally, the upper plane of the vertical fixed end is located at the connection between the composite beam web 21 and the U-shaped steel beam flange plate 26, ensuring that the side of the steel beam flange plate 26 is not affected by the first auxiliary truss 22 and the second auxiliary truss 23, thereby ensuring the ductility of the connection between the steel beam flange plate 26 and the steel truss floor decking plate 12.

[0074] Optionally, when the composite steel beam is used as a frame beam, the center distance from the energy absorption section 1 connecting the composite section 4 to the frame column 3 is selected as the larger value of 1.5H and L / 8; when the composite steel beam is used as a secondary beam, the length of the energy absorption section 1 is designed to be H; wherein H represents the height of the steel beam of the energy absorption section 1, and L represents the horizontal distance between the center points of the two frame columns 3 or the total length of the composite beam. Here, there are certain restrictions on the length of the energy dissipation section 1. Since the frame beam is the main load-bearing structure, the seismic requirements of the frame beam are relatively high, while the secondary beam generally does not have too many requirements for seismic resistance. Therefore, during seismic resistance, if the composite steel beam is used as the frame beam, the center distance from the energy dissipation section 1 connecting the composite section 4 to the frame column 3 is selected as the larger value of 1.5H and L / 8; under the action of external loads, the frame column 3 is subjected to the combined action of tension and pressure, and most of the stress enters the node in the form of peripheral "shear flow" through the bonding effect of the steel bar and concrete, so that the core area of ​​the frame column 3 node is in a pure shear state, and bears the main tensile stress and the main compressive stress. The restriction on the center distance from the energy dissipation section 1 connecting the composite section 4 to the frame column 3 can gradually reduce the tension and shear force at a position far away from the node. The center distance from the energy dissipation section 1 connecting the composite section 4 to the frame column 3 is selected as the larger value of 1.5H and L / 8. After combining its height and length, it can effectively disperse its shear force, further ensuring the shear and bending resistance of the energy dissipation section 1. When the composite steel beam is used as the secondary beam, the center distance from the energy absorption section 1 connecting the composite section 4 to the frame column 3 is taken as H. This design has better bending stiffness. At the same time, since the requirements for the secondary beams in general designs are not as high as those for the frame beams, costs can be saved.

[0075] Optionally, a construction method of a composite steel beam, constructing the composite steel beam, comprises the following steps:

[0076] The I-beam of the energy-absorbing beam section, the U-shaped steel beam 2 of the combined section 4 and the auxiliary steel truss are all processed and formed at one time in the factory and welded and assembled into a combined steel beam; the combined steel beam is connected to the frame columns on both sides;

[0077] The steel bar truss floor deck 12 is laid on the I-beam 11 and the U-shaped steel beam 2, and is cast in one step inside the steel bar truss floor deck and the U-shaped steel beam.

[0078] The construction method of the present invention constructs a new type of composite beam with better rigidity. The U-shaped steel beam is enclosed in concrete and the floor slab concrete is cast at one time, which is convenient for construction and has better combined performance. The building performance (sound insulation, comfort) is better. Compared with concrete beams, it is unnecessary to support formwork and has better energy consumption performance. The mechanical properties of the combination of the I-beam 11, the steel truss floor deck 12 and the U-shaped steel beam can be fully utilized.

[0079] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0080] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A composite steel beam, characterized in that: It comprises an energy consumption section (1) and a combination section (4); The energy absorbing section (1) is directly connected to the frame column (3), and a combination section (4) is located between the energy absorbing sections (1), and the upper planes of the combination section (4) and the two energy absorbing sections (1) are located in the same plane; The energy absorbing section (1) comprises an I-beam (11) and a steel truss floor deck (12) fixedly connected to the upper end of the I-beam (11), and the two energy absorbing sections (1) have the same structure and the same length; The I-beam (11) comprises an upper flange plate (112), a web plate (111) and a lower flange plate (113); the width of the upper flange plate (112) is greater than the width of the lower flange plate (113); and the upper flange plate (112) is fixed to the steel bar truss floor deck (12); The combined section (4) comprises the steel bar truss floor deck (12) and a U-shaped steel beam (2), wherein the U-shaped steel beam (2) is located below the steel bar truss floor deck (12), the steel bar truss floor deck (12) corresponding to the energy dissipation section (1) and the steel bar truss floor deck (12) corresponding to the combined section (4) are integrated, an auxiliary steel bar truss is provided inside the U-shaped steel beam (2), and the inside of the U-shaped steel beam (2) and the inside of the steel bar truss floor deck (12) are cast into one piece; The U-shaped steel beam (2) comprises a composite beam web (21) and a composite beam bottom plate (27); two composite beam webs (21) and one composite beam bottom plate (27) form a U-shaped steel beam (2), and the composite beam bottom plate (27) is perpendicular to the composite beam web (21).

2. The composite steel beam according to claim 1, characterized in that: The energy-consuming section (1) and the combined section (4) are connected via a head plate (5).

3. The composite steel beam according to claim 1, characterized in that: The connection portion between the U-shaped steel beam (2) and the steel bar truss floor deck (12) is divided into a first connection structure, a second connection structure, a third connection structure and a fourth connection structure; The first connection structure, the second connection structure and the third connection structure all include a U-shaped steel beam flange plate (26); the U-shaped steel beam flange plate (26) is located at the connection between the two free ends of the U-shaped steel beam (2) and the steel truss floor deck (12), and the U-shaped steel beam flange plate (26) and the U-shaped steel beam (2) are integrated; In the first connection structure, the U-shaped steel beam flange plate (26) at the upper end of the U-shaped steel beam (2) extends both into the interior of the opening of the U-shaped steel beam (2) and out of the opening of the U-shaped steel beam (2); in the second connection structure, the U-shaped steel beam flange plate (26) at the upper end of the U-shaped steel beam (2) extends into the interior of the opening of the U-shaped steel beam (2); in the third connection structure, the U-shaped steel beam flange plate (26) at the upper end of the U-shaped steel beam (2) extends out of the opening of the U-shaped steel beam (2); and the upper end of the U-shaped steel beam (2) corresponding to the fourth connection structure is directly perpendicular to the steel truss floor deck (12).

4. The composite steel beam according to claim 3, characterized in that: The auxiliary steel bar truss is an X-shaped steel bar truss, and the X-shaped steel bar truss comprises a first auxiliary truss (22) and a second auxiliary truss (23). The free ends of the first auxiliary truss (22) and the second auxiliary truss (23) are both provided with vertical fixed ends, and the vertical fixed ends are in the same direction as the composite beam web (21) and are pressed against the inner wall of the composite beam web (21) and are welded to the inner wall.

5. The composite steel beam according to claim 4, characterized in that: The upper plane of the vertical fixed end is located at the connection between the composite beam web plate (21) and the U-shaped steel beam flange plate (26).

6. The composite steel beam according to claim 3, characterized in that: When the composite steel beam is used as a frame beam, the center distance from the energy absorption section (1) connecting the composite section (4) to the frame column (3) is selected as the larger value of 1.5H and L / 8; when the composite steel beam is used as a secondary beam, the length of the energy absorption section (1) is designed to be H; wherein H represents the height of the steel beam of the energy absorption section (1), and L represents the horizontal distance between the center points of the two frame columns (3) or the total length of the composite steel beam.

7. The composite steel beam according to claim 3, characterized in that: The calculation formula of the bending bearing capacity of the combined section (4) is as follows: M is the bending bearing capacity of the combined section (kN.m); f is the design value of steel bending strength (MPa); A is the flange area of ​​the U-shaped steel beam (mm 2 ); b is the width of the rectangular section (mm); h0 is the effective height of the cross section (mm); f c is the design value of concrete compressive strength (MPa).

8. A construction method for a composite steel beam, characterized in that: The construction of the composite steel beam of claim 1 comprises the following steps: The I-beam (11) of the energy dissipation section (1), the U-shaped steel beam (2) of the combined section (4) and the auxiliary steel bar truss are all processed and formed at one time in a factory and welded and assembled into a combined steel beam; the combined steel beam is connected to the frame columns on both sides; The steel bar truss floor deck (12) is laid on the I-beam (11) and the U-shaped steel beam (2), and is cast in one step inside the steel bar truss floor deck and the U-shaped steel beam.

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