Light steel rib floor support plate and steel beam connecting joint and construction method thereof

Abstract

This invention relates to the field of prefabricated steel structure building technology, and discloses a connection node between a light steel ribbed floor deck and a steel beam and its construction method. The node includes a floor deck and a steel beam. Two floor decks are located on the upper flange of the steel beam, with light steel ribs embedded within them. The ends of the light steel ribs extend out of the floor decks. A purlin support plate is fixed to the upper flange of the steel beam. The web of the light steel rib is in close contact with the surface of the purlin support plate to transfer vertical loads. The surface of the purlin support plate is provided with shear-resistant protrusions. The web of the light steel rib has elongated holes into which the protrusions are embedded. Shear force is transferred horizontally without gaps, while a gap is left in the vertical direction to release deformation constraints. The shear studs are three-section variable cross-section welded studs. The root shear-resistant section bears the shear force, the stress-regulating section has a smaller diameter than the root shear-resistant section and is provided with annular threads, and the necking section elastically elongates under vertical lifting force to absorb deformation energy. Stress relief holes and stress relief grooves provide release space for UHPC shrinkage. This invention achieves structural separation of vertical bearing and horizontal shear resistance, ensuring the shear bearing capacity of the studs.

Description

Technical Field

[0001] This invention relates to the field of prefabricated steel structure building technology, and in particular to a connection node between a light steel ribbed floor deck and a steel beam and its construction method. Background Technology

[0002] In prefabricated steel structure buildings, the connection nodes between the floor deck and the steel beams are the key parts to ensure the overall load-bearing capacity of the floor. The self-supporting light steel progressive rib floor deck uses the internal frame as the main load-bearing structure and has the characteristic of not requiring temporary support.

[0003] Currently, floor decking and steel beams are usually connected by welded shear studs. The studs are welded to the upper flange of the steel beam and anchored in the cast-in-place concrete. The horizontal shear force borne by the floor decking is transmitted to the steel beam in sequence through the floor decking skeleton, concrete, and studs. The transmission of horizontal shear force depends on the concrete as an intermediate medium.

[0004] In ordinary reinforced concrete composite floor slabs, the load-bearing skeleton is evenly distributed, and concrete can meet the requirements as a force transfer medium. However, in self-supporting floor slabs, the load-bearing skeleton is concentrated in specific parts of the floor slab. The load also needs to be transferred to the steel beams through the concrete, but the force transfer is more concentrated, and it is difficult to meet the force transfer requirements by relying solely on the concrete transfer. At the same time, in addition to bearing horizontal shear force, the studs also need to bear vertical pressure and vertical uplift force. Under the combined action of tension and shear, the shear bearing capacity of the studs will decrease, which will make it easy for relative slippage to occur between the floor slab and the steel beam. Summary of the Invention

[0005] To overcome the above shortcomings, the present invention provides a connection node between a light steel ribbed floor deck and a steel beam and its construction method, aiming to solve the problem that the existing stud connection method is difficult to match the concentrated force transmission requirements at the end of the self-supporting light steel ribbed floor deck.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a connection node between a light steel ribbed floor deck and a steel beam, comprising a floor deck and a steel beam, two floor decks symmetrically arranged on the top surface of the upper flange of the steel beam, forming a splice joint between the two floor decks, characterized in that the width of the splice joint is less than the width of the upper flange of the steel beam, a light steel rib is provided inside the floor deck, the end of the light steel rib extends out of the end face of the floor deck, and further includes:

[0007] Purlin support plate, fixed to the top surface of the upper flange of the steel beam, is attached to the web of the light steel rib and provides vertical support for the ends of the light steel rib;

[0008] Shear studs are fixedly installed on the top surface of the upper flange of the steel beam. Multiple shear studs are spaced apart along the length of the steel beam. Each shear stud includes a root shear section, a stress-regulating section, and a top anchoring section arranged sequentially from bottom to top. The root shear section is fixedly connected to the upper flange of the steel beam to bear horizontal shear force. The diameter of the stress-regulating section is smaller than the diameters of the root shear section and the top anchoring section, so that the stress-regulating section forms a necking section between the root shear section and the top anchoring section. When the vertical lifting force is transmitted to the stud, the necking section will generate a small amount of elastic tension when subjected to vertical tension, thereby absorbing most of the deformation of the vertical lifting force, reducing the tension finally transmitted to the root of the stud, and avoiding the root from bearing a large shear force and tension at the same time.

[0009] The UHPC concrete layer is placed within the splice joint, enclosing the purlin support plate, shear studs, and ends of the light steel ribs, so that the components form an integrated whole that works together to bear the load.

[0010] Preferably, a shear-resistant protrusion is fixed to the side of the purlin support plate facing the light steel rib. An elongated hole is opened on the web of the light steel rib, and the shear-resistant protrusion is embedded in the elongated hole. The two are in contact without gap in the horizontal direction, so that the horizontal shear force is rigidly transmitted from the web of the light steel rib to the purlin support plate through the direct contact between the protrusion and the hole wall. A gap is left between the two in the vertical direction, allowing the light steel rib to undergo a small vertical displacement under vertical load without transmitting the vertical deformation constraint force to the shear-resistant protrusion, thereby realizing the structural separation of vertical bearing and horizontal shear resistance.

[0011] Preferably, stress relief holes are provided on the web of the light steel rib. After the UHPC is poured, the stress relief holes on the web of the light steel rib form UHPC pins that penetrate the web of the light steel rib. The UHPC pins are used to transfer the horizontal shear force between the light steel rib and the UHPC concrete layer during the service stage of the node.

[0012] Preferably, the purlin plate is provided with stress relief grooves. The stress relief grooves, together with the stress relief holes and the annular threads, constitute a multi-scale shrinkage stress relief system, which effectively reduces the shrinkage stress of UHPC under the constraint of steel components and suppresses the generation of interface microcracks.

[0013] Preferably, the diameter of the stress-regulating section is 60% to 70% of the diameter of the root shear-resistant section. Within this range, the necking section can generate sufficient elastic elongation to consume vertical deformation energy, while ensuring that the stud as a whole has sufficient shear-resistant cross-sectional area. The root shear-resistant section and the stress-regulating section, as well as the stress-regulating section and the top anchoring section, are connected by arc transitions. The arc transitions between sections eliminate stress concentration at abrupt changes in cross-section, preventing premature fatigue fracture of the stud at the root of the necking section. The outer circumferential surface of the stress-regulating section is provided with annular threads, which provide a deformation interface for shrinkage deformation during the hardening process of UHPC, so that the shrinkage stress is evenly distributed at the interface between the stud and UHPC, avoiding microcracks caused by stress concentration, thereby ensuring the durability of the joint during long-term service.

[0014] Preferably, it also includes fixing bolts. A fixing hole 1 is provided on the web of the light steel rib, and a fixing bolt is provided in the fixing hole 1. A fixing hole 2 is provided on the purlin support plate, and the fixing hole 2 is provided corresponding to the fixing hole 1. The fixing bolt passes through the fixing hole 2 and the fixing hole 1 in sequence, and is fixed to the purlin support plate by a nut to temporarily fix the light steel rib and the purlin support plate. The fixing bolt temporarily fixes the light steel rib to the purlin support plate when the floor deck is hoisted, ensuring accurate hoisting positioning and that the light steel rib does not shift before the UHPC is poured.

[0015] Preferably, the purlin support plate has a reinforcing rib welded to the side away from the light steel rib to enhance the out-of-plane stiffness of the purlin support plate, prevent the purlin support plate from undergoing out-of-plane bending deformation under horizontal shear force, and ensure the effective cooperation between the shear-resistant protrusion and the elongated hole.

[0016] A construction method for the connection node between a light steel ribbed floor deck and a steel beam includes the following steps:

[0017] S1: Complete the hoisting and fixing of the main steel frame beams;

[0018] S2: A purlin support plate is installed on the top surface of the upper flange of the steel beam;

[0019] S3: Install shear studs on the steel beam to fix the root shear section to the top surface of the upper flange of the steel beam;

[0020] S4: Hoist the floor decking so that the light steel rib web is attached to the purlin support plate, the shear protrusion is embedded in the elongated hole, and the light steel rib is temporarily fixed to the purlin support plate by fixing bolts;

[0021] S5: Pour UHPC concrete in the splice joint area to connect the floor decking on both sides into one piece. Use a vibrator to compact it to ensure that the UHPC fully fills the stress relief holes and stress relief grooves, forming a UHPC concrete layer. The UHPC concrete layer encloses the ends of the light steel ribs, purlin support plates and shear studs.

[0022] S6: Maintain the joint area to the design strength requirement.

[0023] Preferably, in step S5, a vibrating tool is used to vibrate the UHPC concrete in the joint area. The vibration range covers the stress relief holes at the ends of the light steel ribs and the stress relief grooves on the surface of the purlin support plate, ensuring that the UHPC grout fully fills these structural spaces, so that the stress relief holes and stress relief grooves can truly perform the function of releasing shrinkage stress after the UHPC hardens.

[0024] Preferably, after the UHPC concrete is poured into the joint area, stress relief holes and stress relief grooves are filled. The stress relief holes provide deformation accommodation space for the shrinkage of UHPC, the stress relief grooves provide buffer space for the shrinkage of UHPC, and the annular threads on the surface of the shear stud stress control section provide a deformation interface for the shrinkage of UHPC. The three work together to reduce the shrinkage stress of UHPC under the constraint of steel components, effectively suppress the generation of interface microcracks, and ensure the long-term durability of the joint.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. In this invention, shear-resistant protrusions are provided on the purlin support plate, and elongated holes are opened on the web of the light steel rib. The protrusions are embedded in the elongated holes and have no gap in horizontal contact, so that the horizontal shear force is transmitted to the purlin support plate through the protrusions and the hole wall. The purlin support plate then directly transmits the horizontal shear force to the steel beam, which solves the problem that the force transfer of the concrete in the self-supporting floor deck is difficult to meet the force transmission requirements due to the force concentration. At the same time, the elongated holes have gaps in the vertical direction, and the vertical force is transmitted through the contact surface between the purlin support plate and the web of the light steel rib, which does not interfere with the force transmission path of the horizontal shear force and avoids local squeezing damage caused by the combined force.

[0027] 2. The stress control section diameter of the shear stud is smaller than that of the root shear section. When the vertical lifting force is transmitted to the stud, the necking section generates a small amount of elastic tension, which absorbs most of the deformation of the vertical lifting force, thereby reducing the tension that is finally transmitted to the stud root. This avoids the root bearing large shear and tension forces at the same time, ensuring the shear bearing capacity of the stud and preventing relative slippage between the floor slab and the steel beam.

[0028] 3. The ends of the light steel ribs, purlin support plates, and shear studs are wrapped as a whole by the UHPC concrete layer, and the components work together to bear the force. The stress relief holes on the web of the light steel ribs, the stress relief grooves on the purlin support plates, and the annular threads of the stress adjustment section of the studs work together to form a multi-shrinkage stress relief system, which effectively suppresses the shrinkage cracks of UHPC under the constraint of steel components and ensures the long-term service performance of the joint. Attached Figure Description

[0029] Figure 1A three-dimensional view of the connection point between the floor deck and the steel beam;

[0030] Figure 2 A three-dimensional view of the connection point between the floor deck and the steel beam after the concrete has been poured.

[0031] Figure 3 This is a structural schematic diagram of light steel ribs, purlin support plates, shear studs, and steel beams;

[0032] Figure 4 Exploded view of the light steel ribs and purlin support plate;

[0033] Figure 5 This is a schematic diagram of the structure of light steel ribs;

[0034] Figure 6 This is a structural schematic diagram of the purlin support plate;

[0035] Figure 7 This is a cross-sectional view of the mating point between the shear-resistant protrusion and the elongated hole;

[0036] Figure 8 This is a three-dimensional diagram of the top anchorage section.

[0037] Figure label:

[0038] 1. Floor deck; 2. Steel beam; 3. Light steel rib; 31. Long slot; 32. Fixing hole one; 33. Stress relief hole; 4. Purlin support plate; 41. Reinforcing rib; 42. Fixing hole two; 43. Stress relief groove; 44. Shear protrusion; 5. Shear stud; 51. Root shear section; 52. Stress control section; 53. Top anchoring section; 6. UHPC concrete layer; 7. Fixing bolt. Detailed Implementation

[0039] Example 1

[0040] Reference Figures 1-8 This embodiment provides a connection node between a light steel ribbed floor deck and a steel beam, including a floor deck 1 and a steel beam 2. The steel beam 2 is made of H-beams, and the top surface of the upper flange serves as the mounting base surface for each component. Two floor decks 1 are symmetrically arranged on the top surface of the upper flange of the steel beam 2, forming a splice between the two floor decks 1. The width of the splice is less than the width of the upper flange of the steel beam 2. The floor deck 1 is a fully prefabricated self-supporting light steel ribbed floor deck. Light steel ribs 3 are provided in the floor deck 1 along the span direction. The light steel ribs 3 are made of C-beams and serve as the longitudinal load-bearing skeleton of the floor deck 1. The light steel ribs 3 are arranged along the span direction of the floor deck 1, and their ends extend out of the end face of the floor deck 1.

[0041] The purlin support plate 4 is cut from steel plate and placed vertically on the top surface of the upper flange of the steel beam 2. Its bottom edge is fully welded to the top surface of the upper flange of the steel beam 2. The purlin support plate 4 is arranged one-to-one with the light steel rib 3. The plate surface of the purlin support plate 4 is attached and fixed to the web plate at the end of the light steel rib 3. The function of the purlin support plate 4 is to provide reliable vertical support for the end of the light steel rib 3, so that the end of the light steel rib 3 is accurately positioned on the steel beam and the force is directly transmitted.

[0042] The shear stud 5 is a three-section variable cross-section cylindrical head weld stud. Multiple shear studs 5 are installed on the top surface of the upper flange of the steel beam 2 between two adjacent purlin support plates 4, and are evenly spaced along the length of the steel beam 2. The shear stud 5 is divided into three sections from bottom to top: the lower end of the root shear section 51 is welded to the top surface of the upper flange of the steel beam 2. The root shear section 51 bears the main horizontal shear force and has the largest diameter to ensure sufficient shear resistance area. The diameter of the stress control section 52 is smaller than that of the root shear section 51, and the diameter of the stress control section 52 is about 60% to 70% of the diameter of the root shear section 51. The root is protected by weakening the stud itself, so that most of the vertical lifting force is absorbed in the necking section before reaching the root weld end.

[0043] The outer circumferential surface of the stress-regulating section 52 is provided with an annular thread. When the UHPC hardens and shrinks, the groove structure of the annular thread converts the axial shrinkage stress into a uniformly distributed compressive stress along the tooth surface through the interlocking interface between the thread teeth and the UHPC material. This avoids the shrinkage stress from concentrating at a certain point at the root of the stud, thereby suppressing the generation of micro-cracks at the interface. At the same time, the necking design of the stress-regulating section 52 causes it to generate a small amount of elastic tension when subjected to vertical lifting force, thereby absorbing most of the deformation of the vertical lifting force and reducing the tension ultimately transmitted to the root of the stud, thus preventing the root from bearing large shear and tensile forces at the same time.

[0044] The root shear section 51 and the stress control section 52, as well as the stress control section 52 and the top anchoring section 53, are all smoothly transitioned by arcs to eliminate stress concentration at the abrupt change in cross-section and to prevent premature fatigue fracture of the stud at the root of the necked section.

[0045] The mechanical principle of the shear stud 5 is as follows: Let the diameter of the stress regulating section 52 be... The diameter of the root shear-resistant segment 51 is Cross-sectional area of ​​stress control section Its axial stiffness ,in The elastic modulus of the stud steel. The length of the stress-adjusting section is determined by the vertical lifting force. When the stress is transferred through the UHPC concrete layer 6 to the top anchorage section 53, the elastic elongation generated by the stress-regulating section 52 is: The remaining tensile force transmitted to the root shear segment 51 is Because the diameter of the necked section is smaller than that of the root shear section, its axial stiffness is reduced. Under the same tensile force, the elongation of the necked section is much greater than that of a stud of equal diameter. Most of the vertical deformation energy is converted into the elastic strain energy of the necked section rather than being transferred to the root weld end.

[0046] Traditional equal-diameter studs simultaneously withstand horizontal shear force and vertical tension The two forces superimposed at the root weld end cause the root section to be in a state of combined tensile and shear stress, which can be addressed using the interaction equation. Description, in which For pure shear ultimate bearing capacity, For pure tensile ultimate bearing capacity, and For the exponential parameter. This equation shows that when... hour The available value is necessarily less than In this embodiment, the tension transmitted to the root is reduced by the elastic elongation of the necking section, and the tension-shear coupling effect is effectively weakened (preventing the bearing capacity of the welded end of the stud root from decreasing due to excessive vertical tension and horizontal shear force at the same time).

[0047] Stress relief holes 33 are also provided on the web plate at the end of the light steel rib 3, and stress relief grooves 43 are provided on the surface of the purlin support plate 4. The stress relief grooves 43 are located in the non-pressure bearing area of ​​the plate surface. After the UHPC is cast, the stress relief holes 33 provide deformation accommodation space for the shrinkage deformation of the UHPC, and the stress relief grooves 43 provide buffer space for the shrinkage of the UHPC. Together with the annular threads on the surface of the stress adjustment section 52 of the shear stud 5, they form a triple shrinkage stress relief system.

[0048] When UHPC hardens and shrinks under the constraint of steel components, it generates constraint shrinkage stress. ,in The elastic modulus of UHPC For the free contraction strain of UHPC, This represents the actual contraction strain after being constrained; the stronger the constraint, the greater the strain. The closer , The larger the stress relief hole 33, the stress relief groove 43 and the annular thread are, the greater the constraint degree is. The stress relief hole 33 provides deformation accommodation space for UHPC shrinkage, the stress relief groove provides buffer space for UHPC shrinkage, and the annular thread increases the contact area between UHPC and stud and makes the distribution of shrinkage stress on the interface more uniform.

[0049] After the UHPC hardens, the stress relief hole 33 also has another function: after being filled by the UHPC, it forms a UHPC pin key that penetrates the web of the light steel rib, enhancing the mechanical interlocking and shear resistance between the UHPC and the light steel rib. Before the UHPC hardens, the stress relief hole 33 serves as a shrinkage release space, and after the UHPC hardens, it serves as a shear resistance pin key, realizing a dual purpose of one hole.

[0050] Fixing hole 32 is provided on the web plate at the end of the light steel rib 3, and fixing hole 42 is provided on the corresponding position on the surface of the purlin support plate 4. Fixing hole 32 and fixing hole 42 are aligned. The connection node also includes fixing bolt 7. After the floor deck 1 is hoisted into place, the fixing bolt 7 passes through fixing hole 42 and fixing hole 32 in sequence and is tightened with nuts to temporarily fix the light steel rib 3 to the purlin support plate 4, ensuring accurate hoisting positioning and that the light steel rib 3 does not shift before the UHPC is poured.

[0051] In this embodiment, the positioning requirements during the construction phase and the force transmission requirements during the service phase are assigned to different components. The fixing bolts undertake the former, while the purlin plate mating surface, the shear protrusion and the elongated hole, and the UHPC wrapping undertake the latter. This makes the force transmission path of the node in the service state purer and does not introduce additional bolt force transmission paths to interfere with the mechanical analysis.

[0052] UHPC concrete layer 6 is made of high-performance concrete and is poured in the joint area. The pouring thickness is the same as the surface layer thickness of the floor deck 1. During pouring, a vibrating tool is used to compact it to ensure that the UHPC fully fills the stress relief holes 33 and stress relief grooves 43, forming UHPC concrete layer 6, which completely encloses the ends of the light steel ribs 3, the purlin support plate 4 and the shear studs 5.

[0053] The function of the UHPC concrete layer 6 is to connect the two floor decks 1, the ends of the light steel ribs 3, the purlin support plate 4, and the shear studs 5 into a whole, so that there are no gaps or slippage between the components, and the components are coordinated to bear the load. Through the high bonding strength and rigidity of UHPC, the components are wrapped into a whole, so that the components deform together and bear the load together during the service process, and the overall integrity of the floor is improved.

[0054] The three-section variable cross-section processing of the shear stud 5, the opening of the web of the light steel rib 3, and the protrusions and grooves on the surface of the purlin support plate 4 are all completed in the factory prefabrication stage, and only positioning, hoisting and pouring are required on site.

[0055] Example 2

[0056] Reference Figure 6 Unlike Embodiment 1, in this embodiment, the purlin support plate 4 is fixed with a shear-resistant protrusion 44 on the side facing the light steel rib 3, and a corresponding elongated hole 31 is opened on the web plate at the end of the light steel rib 3, and the shear-resistant protrusion 44 is embedded in the elongated hole 31.

[0057] The shear-resistant protrusion 44 and the elongated hole 31 are in close contact in the horizontal direction without any gap, so that the horizontal shear force can be rigidly transferred from the web of the light steel rib 3 to the purlin support plate 4 through the direct contact between the protrusion and the hole wall; the two are separated in the vertical direction, allowing the light steel rib 3 to undergo a small amount of free displacement under vertical load without transferring the vertical deformation constraint force to the shear-resistant protrusion 44.

[0058] This design achieves structural separation of vertical bearing capacity and horizontal shear resistance. Vertical loads are directly transmitted through the contact surface between the web of the light steel rib 3 and the purlin support plate 4, while horizontal shear forces are transmitted through the rigid contact between the shear-resistant protrusion 44 and the wall of the elongated hole 31. The two force transmission paths do not interfere with each other and work independently.

[0059] The structure, position and connection relationship of the remaining components are the same as in Embodiment 1, and will not be described again here.

[0060] Example 3

[0061] This embodiment provides a construction method for the connection node between a light steel ribbed floor deck and a steel beam, including the following steps:

[0062] Step 1: Complete the hoisting and fixing of the main steel frame steel beam 2. Hoist the steel beam 2 to the preset position and weld or bolt it to the steel column to form a stable main steel frame.

[0063] Step 2: Place the purlin support plate 4 vertically on the top surface of the upper flange of the steel beam 2, so that its bottom edge is in contact with the top surface of the upper flange of the steel beam 2. Fix the purlin support plate 4 to the top surface of the upper flange of the steel beam 2 by full welding, and weld the reinforcing rib 41 on the side of the purlin support plate 4 away from the light steel rib 3. The position of the purlin support plate 4 corresponds one-to-one with the light steel rib 3 in the floor deck 1, ensuring that the plate surface of the purlin support plate 4 and the web of the end of the light steel rib 3 to be installed later are in the same plane.

[0064] Step 3: Fix the shear studs 5 on the steel beam 2, and weld the lower end of the root shear section 51 to the top surface of the upper flange of the steel beam 2. The shear studs 5 are set between two adjacent purlin support plates 4 and are arranged at equal intervals along the length of the steel beam 2 according to the design requirements.

[0065] Step 4: Hoist the floor deck 1 above the steel beam 2 and slowly lower it so that the web of the end of the light steel rib 3 is in contact with the surface of the purlin support plate 4. At the same time, make the pre-set anti-shear protrusion 44 on the purlin support plate 4 embed into the elongated hole 31 opened on the web of the light steel rib 3. Adjust the position of the floor deck 1 to ensure that the anti-shear protrusion 44 and the elongated hole 31 are in horizontal contact without gaps and have gaps in the vertical direction. Pass the fixing bolts 7 through the fixing hole 2 42 on the purlin support plate 4 and the fixing hole 1 32 on the web of the light steel rib 3 in sequence, and tighten them with nuts to temporarily fix the light steel rib 3 to the purlin support plate 4, ensuring accurate hoisting and positioning and that the light steel rib 3 does not shift before the subsequent pouring of UHPC.

[0066] Step 5: Pour UHPC concrete within the area enclosed by the floor deck 1 and steel beam 2. Use a vibrator to thoroughly compact the UHPC concrete in the joint area, covering the stress relief holes 33 at the ends of the light steel ribs 3 and the stress relief grooves 43 on the surface of the purlin support plate 4. Ensure that the UHPC grout fully fills the stress relief holes 33 and stress relief grooves 43. The pouring thickness of the UHPC concrete should be consistent with the surface layer thickness of the floor deck 1. After the UHPC concrete pouring is completed, the UHPC concrete layer 6 will completely enclose the ends of the light steel ribs 3, the purlin support plate 4, and the shear studs 5, forming... The overall wrapping effect is achieved by anchoring the top anchoring section 53 of the shear stud 5 into the UHPC concrete layer 6. After the UHPC concrete is poured into the joint area, it fills the stress relief holes 33 and stress relief grooves 43. The stress relief holes 33 provide deformation accommodation space for the shrinkage of the UHPC, and the stress relief grooves 43 provide buffer space for the shrinkage of the UHPC. The annular threads on the surface of the stress control section 52 of the shear stud 5 provide a deformation interface for the shrinkage of the UHPC. The three work together to reduce the shrinkage stress of the UHPC under the constraint of the steel structure, effectively suppress the generation of micro-cracks at the interface, and ensure the long-term durability of the joint.

[0067] Step Six: After the UHPC concrete is poured, the joint area is cured by covering and moisturizing or applying curing agent until the UHPC concrete layer 6 reaches the design strength grade. During the curing period, the joint area should be protected from impact and vibration loads.

[0068] Compared with traditional construction methods, in the construction method of this embodiment, the three-section variable cross-section processing of the shear studs 5, the elongated holes 31 and stress relief holes 33 on the web of the light steel ribs 3, and the shear protrusions 44 and stress relief grooves 43 on the purlin support plate 4 are all completed in the factory prefabrication stage. On-site, only hoisting, positioning, temporary fixing and pouring operations are required. There is no need to erect a large number of temporary supports, which makes the construction efficiency high and the operation simple. The fixing bolts 7 are only used for temporary positioning during the construction stage and do not participate in the stress during the service stage. After the floor deck 1 is hoisted into place, a stable construction platform can be formed.

Claims

1. A connection node between a light steel ribbed floor deck and a steel beam, comprising a floor deck (1) and a steel beam (2), wherein two floor decks (1) are symmetrically arranged on the top surface of the upper flange of the steel beam (2), and a splice joint is formed between the two floor decks (1), characterized in that, The width of the splice joint is less than the width of the upper flange of the steel beam (2). Light steel ribs (3) are provided inside the floor deck (1). The ends of the light steel ribs (3) extend out of the end face of the floor deck (1). It also includes: Purlin support plate (4) is fixed to the top surface of the upper flange of the steel beam (2), and purlin support plate (4) is attached to and fixed to the web of the light steel rib (3); Shear studs (5) are fixedly installed on the top surface of the upper flange of the steel beam (2). Multiple shear studs (5) are spaced apart along the length of the steel beam (2). The shear studs (5) include a root shear section (51), a stress adjustment section (52) and a top anchoring section (53) arranged sequentially from bottom to top. The root shear section (51) is fixedly connected to the upper flange of the steel beam (2). The diameter of the stress adjustment section (52) is smaller than the diameter of the root shear section (51) and the top anchoring section (53). The UHPC concrete layer (6) is placed inside the splice joint and wraps around the ends of the purlin support plate (4), shear studs (5) and light steel ribs (3).

2. The connection node between a light steel ribbed floor deck and a steel beam according to claim 1, characterized in that, The purlin support plate (4) is fixed with a shear protrusion (44) on the side facing the light steel rib (3). The web of the light steel rib (3) is provided with an elongated hole (31). The shear protrusion (44) is embedded in the elongated hole (31). The two are in contact without gap in the horizontal direction and have a gap in the vertical direction.

3. The connection node between a light steel ribbed floor deck and a steel beam according to claim 1, characterized in that, The web of the light steel rib (3) is provided with stress relief holes (33). After the UHPC is poured, the stress relief holes (33) on the web of the light steel rib (3) form UHPC pins that penetrate the web of the light steel rib. The UHPC pins are used to transfer the horizontal shear force between the light steel rib (3) and the UHPC concrete layer (6) during the node service stage.

4. The connection node between a light steel ribbed floor deck and a steel beam according to claim 1, characterized in that, The purlin support plate (4) is provided with a stress relief groove (43).

5. The connection node between a light steel ribbed floor deck and a steel beam according to claim 1, characterized in that, The diameter of the stress control section (52) is 60% to 70% of the diameter of the root shear section (51). The root shear section (51) and the stress control section (52), as well as the stress control section (52) and the top anchoring section (53), are connected by a circular arc transition. The outer circumferential surface of the stress control section (52) is provided with annular threads.

6. The connection node between a light steel ribbed floor deck and a steel beam according to claim 1, characterized in that, The light steel rib (3) has a fixing hole 1 (32) on its web, and a fixing bolt (7) is installed in the fixing hole 1 (32). The purlin support plate (4) has a fixing hole 2 (42) which is corresponding to the fixing hole 1 (32). The fixing bolt (7) passes through the fixing hole 2 (42) and the fixing hole 1 (32) in sequence, and is fixed to the purlin support plate (4) by a nut to temporarily fix the light steel rib (3) and the purlin support plate (4).

7. A connection node between a light steel ribbed floor deck and a steel beam according to any one of claims 1 to 6, characterized in that, The purlin support plate (4) has a reinforcing rib (41) welded to the side away from the light steel rib (3).

8. A construction method for the connection node between a light steel ribbed floor deck and a steel beam, characterized in that, Includes the following steps: S1: Complete the hoisting and fixing of the main steel frame steel beams (2); S2: A purlin support plate (4) is installed on the top surface of the upper flange of the steel beam (2); S3: Install shear studs (5) on the steel beam (2) and fix the root shear section (51) to the top surface of the upper flange of the steel beam (2); S4: Hoist the floor deck (1) so that the web of the light steel rib (3) fits against the purlin support plate (4), and the shear protrusion (44) is embedded in the elongated hole (31). The light steel rib (3) is temporarily fixed to the purlin support plate (4) by fixing bolts (7). S5: Pour UHPC concrete in the splice joint area to connect the floor decks on both sides into one piece. Use a vibrating tool to compact it to ensure that the UHPC fully fills the stress relief holes (33) and stress relief grooves (43) to form a UHPC concrete layer (6). The UHPC concrete layer (6) encloses the ends of the light steel ribs (3), the purlin support plate (4), and the shear studs (5). S6: Maintain the joint area to the design strength requirement.

9. A construction method for a connection node between a light steel ribbed floor deck and a steel beam according to claim 8, characterized in that, In step S5, a vibrating tool is used to vibrate the UHPC concrete in the splice joint area. The vibration range covers the stress relief holes (33) at the ends of the light steel ribs (3) and the stress relief grooves (43) on the surface of the purlin support plate (4).

10. A construction method for a connection node between a light steel ribbed floor deck and a steel beam according to claim 8, characterized in that, After the UHPC concrete is poured into the joint area, stress relief holes (33) and stress relief grooves (43) are filled. The stress relief holes (33) provide deformation accommodation space for the shrinkage of UHPC, and the stress relief grooves (43) provide buffer space for the shrinkage of UHPC. The annular threads on the surface of the stress adjustment section (52) of the shear stud (5) provide a deformation interface for the shrinkage of UHPC.

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