Concrete beam and steel beam connecting joint and engineering calculation method thereof

Abstract

The invention relates to a concrete beam and steel beam connecting node and an engineering calculation method thereof. According to the connecting node, a secondary steel beam is arranged perpendicular to a main concrete beam, a connecting point is fixed through a connecting plate, a first embedded part is arranged on the upper surface of a concrete short beam, and first bedding is arranged above the first embedded part and connected with a lower flange of the secondary steel beam; the concrete short beam is fixedly connected to the lower portion of the side wall of the main concrete beam, a first anchor bolt is arranged in the concrete short beam, and the first anchor bolt extends out of the top of the concrete short beam and the first bedding mortar and extends into the secondary steel beam to be fixed; second embedded parts are arranged on the upper portions of the side walls of the main concrete beams. A second anchor bolt is arranged in the main concrete beam and extends out of the main concrete beam to be connected with a second embedded part; the connecting plate is vertically welded to the side face of the second embedded part, and the secondary steel beam is connected with the connecting plate through bolts. The calculation method comprises the following steps: 1) designing a concrete short beam; (2) carrying out shearing resistance checking calculation on the embedded part; and 3) summarizing the steps, and outputting a calculation scheme and a result.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering design, and in particular relates to an engineering calculation method for a connection node between a concrete beam and a steel beam. Background Art

[0002] With the rapid growth of my country's economy, the construction industry has achieved remarkable development, and the number of structures in which steel and concrete are mixed is increasing. In industrial projects, the need to connect steel beams to concrete main beams is particularly common. According to the general practice of the existing standard drawings, the load of the steel beam is transferred to the embedded parts on the side of the concrete beam through the T-type connector, and finally borne by the reinforced concrete beam. The bearing capacity of this node mainly depends on the shear bearing capacity of the embedded plate. However, this node adopts a mixed force method of installing bolts and welding, which requires on-site welding operations and is inconvenient to construct. In particular, the failure mechanism and reliability of the bolt-welded hybrid connection under earthquake action are still unclear, so it is worth considering its use in cases with a higher seismic fortification level. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a reasonable method for evaluating the bearing capacity of node embedded plates.

[0004] The present invention solves the above-mentioned problem by adopting the following technical solution:

[0005] A connection node between a concrete beam and a steel beam comprises a main concrete beam, a secondary steel beam and a connection plate, wherein the secondary steel beam is arranged perpendicular to the main concrete beam, and the connection point is fixed by the connection plate. The node also comprises a first embedded part, a first mortar, a first anchor bolt, a second embedded part, a second anchor bolt, a connection plate, a bolt, a stiffening plate and a concrete short beam, wherein the first embedded part is arranged on the upper surface of the concrete short beam, the first mortar is arranged above the first embedded part and is connected to the lower flange of the secondary steel beam; the concrete short beam is fixedly connected to the lower part of the side wall of the main concrete beam, a first anchor bolt is arranged inside the concrete short beam, the first anchor bolt extends out of the top of the concrete short beam and the first mortar, and extends into the secondary steel beam for fixing; a second embedded part is arranged on the upper part of the side wall of the main concrete beam; a second anchor bolt is arranged inside the main concrete beam, and the second anchor bolt extends out of the main concrete beam to connect with the second embedded part; the connection plate is vertically welded to the side surface of the second embedded part, and the secondary steel beam is connected to the connection plate by bolts.

[0006] The present invention also provides an engineering calculation method for the connection node of a concrete beam and a steel beam, and the specific steps are as follows:

[0007] Step 1: Design of short concrete beams

[0008] S1: Preliminary selection of the node's geometric and material properties, including: concrete strength grade, reinforcement grade, short column size and node design value, etc.;

[0009] S2: Bring in the initially selected node attributes to perform crack resistance calculation of the inclined section. If the properties meet the requirements, proceed to the next step. If not, return to S1.

[0010] S3: Bring in the initially selected node attributes to perform local pressure verification. If the properties meet the requirements, proceed to the next step. If not, return to S1.

[0011] S4: Bring in the initially selected node attributes to perform normal section bending calculation. If satisfied, proceed to the next step of verification. If not satisfied, return to S1.

[0012] S5: Bring in the initially selected node attributes to calculate the area of ​​horizontal stirrups / bent steel bars. If the calculation is satisfactory, complete the calculation. If not, return to S1.

[0013] Step 2: Check the shear resistance of embedded parts. Select anchor bolts according to the required external force, assuming that the horizontal force of the steel beam is completely borne by the anchor bolts.

[0014] Step 3: Summarize the above steps and output the calculation plan and results.

[0015] More specifically, the design calculation of the concrete short beam in step 1 is:

[0016] S1: Refer to the Code for Design of Concrete Structures (GB 50010-2010 (2015 Edition)), Article 9.3.10, to check the crack resistance of the inclined section of short beam concrete:

[0017] h0=h1-a s +ctan(α1)

[0018] =290-40+567×0.988=810mm

[0019] F vk =420kN<F vkt =460.675kN

[0020] Where:

[0021] a s ——thickness of longitudinal reinforcement protection layer, in mm;

[0022] α1——45 degrees;

[0023] S2: Refer to Article 9.3.10 of the Code for Design of Concrete Structures to perform local compression calculations:

[0024] Where:

[0025] A——Area of ​​the first embedded plate, unit: mm 2 ;

[0026] S3: Refer to Article 9.3.11 of the Code for Design of Concrete Structures to calculate the bending resistance of the normal section:

[0027] (1) Shear span ratio:

[0028]

[0029] (2) Calculation of longitudinal reinforcement:

[0030]

[0031] Where:

[0032] a——the side distance of the concrete beam close to one side of the vertical force application point, in mm;

[0033] S4: Calculate the area of ​​horizontal stirrups / bent steel bars according to Section 9.3.13 of the Concrete Code

[0034] (1) Calculation of horizontal stirrup area:

[0035] A Sh >0.5A s1 =0.5×824=412mm 2

[0036] Stirrups actual distribution: d8@130(2)

[0037] A Sh =418mm 2 >412m m According to shear span ratio Bent steel bars should be provided

[0038] (2) Calculation of the area of ​​bent steel bars:

[0039] A Sb >0.5A s1 =0.5×824=412mm 2

[0040] (3) Bend reinforcement: 3D16

[0041] A Sb =603mm 2 >412mm 2 .

[0042] More specifically, the shear calculation of embedded parts in step 2 is as follows:

[0043] First embedded parts calculation: select anchor bolts according to the required external force, assuming that the horizontal force of the steel beam is completely borne by the anchor bolts.

[0044]

[0045] Where:

[0046] n n - number of anchor bolts;

[0047] ——Anchor bolt strength design value N / mm 2 ;

[0048] n v - shear surface of anchor bolt;

[0049] Step 3: Summarize the above steps and output the calculation plan and results;

[0050] Longitudinal reinforcement: 6D18

[0051] A s =1527mm 2 >1418mm 2

[0052] Stirrups actual distribution: d8@130(2)

[0053] A Sh =418mm 2 >412mm 2

[0054] Bending reinforcement: 3D16

[0055] A Sb =603mm 2 >412mm 2

[0056] Actual embedded parts configuration: 4×30D.

[0057] Compared with the traditional connection method, the connection node of a concrete beam and a steel beam and the engineering calculation method thereof provided by the present invention have the following advantages:

[0058] (1) Advantages of connecting nodes:

[0059] First, it has a large bearing capacity and can meet the strength standards required by the design; second, it realizes the leveling design of the nodes, which greatly facilitates the construction process and helps to improve the construction quality; finally, the force transmission mechanism is simple and reasonable, which can effectively ensure the effective transmission of shear force, thereby ensuring the safety of the structure.

[0060] (2) Advantages of engineering calculation methods:

[0061] The present invention retains some embedded parts and connections as safety redundancy during design, thereby enhancing the safety of the structure. Under the action of an earthquake, the calculation method can provide sufficient ductility and energy dissipation capacity, and has good seismic resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a structural schematic diagram of a connection node between a concrete beam and a steel beam proposed by the present invention;

[0063] Figure 2 This is the front view of the connection node between the concrete beam and the steel beam in implementation case 1;

[0064] Figure 3 This is a top view of the connection node between the concrete beam and the steel beam in implementation case 1;

[0065] Figure 4 This is a calculation diagram for the example project in Case 2;

[0066] Figure 5 A flow chart of a connection node between a concrete beam and a steel beam and an engineering calculation method provided by the present invention.

[0067] In the figure: main concrete beam 1, secondary steel beam 2, first embedded part 3, first mortar 4, first anchor bolt 5, second embedded part 6, second anchor bolt 7, connecting plate 8, bolt 9, stiffening plate 10 and concrete short beam 11. DETAILED DESCRIPTION

[0068] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the implementation modes and the accompanying drawings. Here, the schematic implementation modes of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0069] Node structure of the present invention:

[0070] See also Figure 1-Figure 4 One aspect of the present invention provides a connection node between a concrete beam and a steel beam, including a main concrete beam 1, a secondary steel beam 2, a first embedded part 3, a first mortar 4, a first anchor bolt 5, a second embedded part 6, a second anchor bolt 7, a connecting plate 8, a bolt 9, a stiffening plate 10 and a concrete short beam 11.

[0071] The first embedded part 3 is arranged on the upper surface of the concrete short beam 11, and the first mortar 4 is arranged above the first embedded part 3 and connected to the lower flange of the secondary steel beam 2;

[0072] A first anchor bolt 5 is arranged inside the concrete short beam 11, and the first anchor bolt 5 extends out of the top of the concrete short beam 11 and the first mortar 4, and extends into the secondary steel beam 2 for fixing;

[0073] The web plate of the secondary steel beam 2 and the connecting plate 8 are provided with corresponding bolt holes.

[0074] A second embedded part 6 is arranged on the same side and upper part of the main concrete beam 1 and the concrete short beam 11; a second anchor bolt 7 is arranged inside the main concrete beam 1, and the second anchor bolt 7 extends out of the main concrete beam 1 to connect with the second embedded part 6;

[0075] A connecting plate 8 is vertically welded to the side of the second embedded part 6 , and the secondary steel beam 2 is connected to the connecting plate by bolts 9 .

[0076] More specifically, in order to further enhance the structural strength of the secondary steel beam 2 , a stiffening plate 10 perpendicular to the longitudinal axis of the secondary steel beam 2 is further provided inside the secondary steel beam 2 in this example.

[0077] More specifically, the thickness of the stiffening plate 10 should not be less than the thickness of the web to which it is connected.

[0078] During operation, first weld the connecting plate 8 to the second embedded part 6, ensuring that the connecting plate 8 is perpendicular to the side of the second embedded part 6. Then temporarily connect the lower flange of the secondary steel beam 2 to the first anchor bolt 5, and then level it through the first mortar 4 until the bolt holes on the secondary steel beam 2 and the bolt holes on the connecting plate 8 are aligned, and screw in the bolts 9 to make the connecting plate 8 and the secondary steel beam 2 tightly connected. After that, when the first mortar 4 reaches the designed strength, tighten the nut of the first anchor bolt 5 and weld it;

[0079] See also Figure 5 In another aspect of the present invention, there is provided an engineering calculation method for the connection node between a concrete beam and a steel beam, and the specific steps are as follows:

[0080] Step 1: Design of short concrete beams

[0081] S1: Preliminary selection of the node's geometric and material properties, including: concrete strength grade, reinforcement grade, short column size and node design value, etc.

[0082] S2: Bring in the primary selected nodes to perform crack resistance verification on the inclined section. If satisfied, proceed to the next step, otherwise return to S1.

[0083] S3: Bring in the preliminarily selected nodes to perform local pressure verification. If satisfied, proceed to the next step, otherwise return to S1.

[0084] S4: Bring in the primary selected nodes to perform the bending resistance calculation of the positive section. If it meets the requirements, proceed to the next step of verification, otherwise return to S1.

[0085] S5: Bring in the primary selected nodes to calculate the area of ​​horizontal stirrups / bent steel bars. If satisfied, complete the calculation; otherwise, return to S1.

[0086] Step 2: Shear calculation of embedded parts

[0087] The anchor bolts are selected according to the required external force, assuming that the horizontal force of the steel beam is completely borne by the anchor bolts.

[0088] Step 3: Summarize the above steps and output the calculation plan and results.

[0089] The present invention is specifically described below in conjunction with a specific example. The concrete beam and short beam concrete of a certain project are both made of C25. The horizontal force transmitted by the steel beam is 110 kN, and the vertical force is 420 kN. The detailed information is shown in Table 1:

[0090] Table 1 Node information details

[0091]

[0092] Step 1: Design of short concrete beams

[0093] S1: Refer to the Code for Design of Concrete Structures (GB 50010-2010 (2015 Edition)), Article 9.3.10, to check the crack resistance of the inclined section of short beam concrete:

[0094] h0=h1-a s +ctan(α1)

[0095] =290-40+567×0.988=810mm

[0096]

[0097] F vk =450kN<F vkt =460.675kN

[0098] Where:

[0099] a s ——thickness of longitudinal reinforcement protection layer, in mm;

[0100] α1——45 degrees;

[0101] S2: Refer to Article 9.3.10 of the Code for Design of Concrete Structures to perform local compression calculations:

[0102]

[0103] Where:

[0104] A——Area of ​​the first embedded plate, unit: mm 2 ;

[0105] S3: Refer to Article 9.3.11 of the Code for Design of Concrete Structures to calculate the bending resistance of the normal section:

[0106] (1) Shear span ratio:

[0107]

[0108] (2) Calculation of longitudinal reinforcement:

[0109]

[0110] Where:

[0111] a——the side distance of the concrete beam close to one side of the vertical force application point, in mm;

[0112] S4: Calculate the area of ​​horizontal stirrups / bent steel bars according to Section 9.3.13 of the Concrete Code.

[0113] (1) Calculation of horizontal stirrup area:

[0114] A Sh >0.5 s1 =0.5×824=412mm 2

[0115] Stirrups actual distribution: d8@130(2)

[0116] A Sh =418mm 2 >142mm 2

[0117] According to shear span ratio Bent steel bars should be provided

[0118] (2) Calculation of the area of ​​bent steel bars:

[0119] A Sb >0.5A s1 =0.5×824=412mm 2

[0120] (3) Bend reinforcement: 3D16

[0121] A Sb =603mm 2 >412mm 2

[0122] Step 2: Shear calculation of embedded parts

[0123] First embedded parts calculation: select anchor bolts according to the required external force, assuming that the horizontal force of the steel beam is completely borne by the anchor bolts.

[0124]

[0125] Where:

[0126] n n - number of anchor bolts;

[0127] ——Anchor bolt strength design value N / mm 2 ;

[0128] n v - shear surface of anchor bolt;

[0129] Step 3: Summarize the above steps and output the calculation plan and results

[0130] Longitudinal reinforcement: 6D18

[0131] A s =1527mm 2 >1418mm 2

[0132] Stirrups actual distribution: d8@130(2)

[0133] A Sh =418mm 2 >412mm 2

[0134] Bending reinforcement: 3D16

[0135] A Sb =603mm 2 >412mm 2

[0136] Embedded parts: 4×30D

[0137] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by any person skilled in the art based on the above disclosed technical contents shall be regarded as equivalent effective embodiments and shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A connection node between a concrete beam and a steel beam, comprising a main concrete beam, a secondary steel beam and a connection plate, wherein the secondary steel beam is arranged perpendicular to the main concrete beam, and the connection point is fixed by the connection plate, characterized in that: It also includes a first embedded part, a first mortar, a first anchor bolt, a second embedded part, a second anchor bolt, a connecting plate, a bolt, a stiffening plate and a short concrete beam. The first embedded part is arranged on the upper surface of the concrete short beam, and the first mortar is arranged above the first embedded part and connected with the lower flange of the secondary steel beam; The short concrete beam is fixedly connected to the lower part of the side wall of the main concrete beam, and a first anchor bolt is arranged inside the short concrete beam. The first anchor bolt extends out of the top of the short concrete beam and the first mortar, and extends into the secondary steel beam for fixing; A second embedded part is arranged on the upper part of the side wall of the main concrete beam; a second anchor bolt is arranged inside the main concrete beam, and the second anchor bolt extends out of the main concrete beam to connect the second embedded part; the connecting plate is vertically welded on the side of the second embedded part, and the secondary steel beam is connected to the connecting plate by bolts.

2. The connection node between a concrete beam and a steel beam according to claim 1, characterized in that: Corresponding bolt holes are provided on the web plate and the connecting plate of the secondary steel beam.

3. The connection node between a concrete beam and a steel beam according to claim 1, characterized in that: A stiffening plate perpendicular to the longitudinal axis of the secondary steel beam is arranged inside the secondary steel beam.

4. The connection node between a concrete beam and a steel beam according to claim 3, characterized in that: The thickness of the stiffening plate should not be less than the thickness of the web to which it is connected.

5. The engineering calculation method for the connection node between the concrete beam and the steel beam as described in claim 1, wherein the method stipulates that the force transmitted by the steel beam is entirely borne by the short concrete beam, and the second embedded parts, the second anchor bolts, the connecting plates and the bolts are only considered for installation and fixing, and is characterized in that: The specific steps are as follows: Step 1: Design of short concrete beams S1: Preliminary selection of the node's geometric and material properties, including: concrete strength grade, reinforcement grade, short column size and node design value, etc.; S2: Bring in the initially selected node attributes to perform crack resistance calculation of the inclined section. If the properties meet the requirements, proceed to the next step. If not, return to S1. S3: Bring in the initially selected node attributes to perform local pressure verification. If the properties meet the requirements, proceed to the next step. If not, return to S1. S4: Bring in the initially selected node attributes to perform normal section bending calculation. If satisfied, proceed to the next step of verification. If not satisfied, return to S1. S5: Bring in the initially selected node attributes to calculate the area of ​​horizontal stirrups / bent steel bars. If the calculation is satisfactory, complete the calculation. If not, return to S1. Step 2: Check the shear resistance of embedded parts. Select anchor bolts according to the required external force, assuming that the horizontal force of the steel beam is completely borne by the anchor bolts. Step 3: Summarize the above steps and output the calculation plan and results.

6. The engineering calculation method for the connection node between a concrete beam and a steel beam according to claim 5 is characterized in that: The specific design calculation of the concrete short beam in step 1 is: S1: Refer to the Code for Design of Concrete Structures (GB 50010-2010 (2015 Edition)), Article 9.3.10, to check the crack resistance of the inclined section of short beam concrete: h0=h1-a s +ctan(α1) =290-40+567×0.988=810mm F vk =420kN<F vkt =460.675kN Where: a s ——thickness of longitudinal reinforcement protection layer, in mm; α1——45 degrees; S2: Refer to Article 9.3.10 of the Code for Design of Concrete Structures to perform local compression calculations: Where: A——Area of ​​the first embedded plate, unit: mm 2 ; S3: Refer to Article 9.3.11 of the Code for Design of Concrete Structures to calculate the bending resistance of the normal section: (1) Shear span ratio: (2) Calculation of longitudinal reinforcement: Where: a——the side distance of the concrete beam close to one side of the vertical force application point, in mm; S4: Calculate the area of ​​horizontal stirrups / bent steel bars according to Section 9.3.13 of the Concrete Code (1) Calculation of horizontal stirrup area: A Sh >0.5A s1 =0.5×824=412mm 2 Stirrups actual distribution: d8@130(2) A Sh =418mm 2 >412mm 2 According to shear span ratio Bent steel bars should be provided (2) Calculation of the area of ​​bent steel bars: A Sb >0.5A s1 =0.5×824=412mm 2 (3) Bend reinforcement: 3D16 A Sb =603mm 2 >412mm2 2 。 7. The engineering calculation method for the connection node between a concrete beam and a steel beam according to claim 5 is characterized in that: The specific shear calculation of embedded parts in step 2 is: First embedded parts calculation: select anchor bolts according to the required external force, assuming that the horizontal force of the steel beam is completely borne by the anchor bolts. Where: n n - number of anchor bolts; ——Anchor bolt strength design value N / mm 2 ; n v - shear surface of anchor bolt; Step 3: Summarize the above steps and output the calculation plan and results; Longitudinal reinforcement: 6D18 A s =1527mm 2 >1418mm 2 Stirrups actual distribution: d8@130(2) A Sh =418mm 2 >412mm 2 Bending reinforcement: 3D16 A Sb =603mm 2 >412mm 2 Actual embedded parts configuration: 4×30D.

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