Steel bar inclined interaction locking bridge deck slab connecting structure and design method

Abstract

The invention discloses a reinforcing steel bar inclined interactive locking bridge deck slab connecting structure and a design method. A first prefabricated bridge deck slab and a second prefabricated bridge deck slab reserve first inclined gate-type reinforcing steel bars and second inclined gate-type reinforcing steel bars at the transverse end of a wet joint correspondingly and are arranged at equal intervals in the length direction of the wet joint; the first inclined door-type steel bar and the second inclined door-type steel bar are mutually sleeved and locked to form an inclined interaction locking shape, the horizontal lap joint length of the inclined interaction locking inclined door-type steel bars and the minimum width of the wet joint are determined, and at least four longitudinal straight line penetrating steel bars vertically penetrate through the whole wet joint length from the corners of the inner periphery of a hole channel formed by inclined interaction locking. By means of the first inclined door-type steel bars and the second inclined door-type steel bars which are arranged in the inclined mode, the length of the middle-section rotary steel bars is increased, the problem that thin plate structure connecting steel bars cannot be bent in a rotary mode is solved, the tensile bearing capacity of connection is greatly improved compared with linear steel bars, and meanwhile the lap joint length of the reserved steel bars can be reduced.

Description

Technical Field

[0001] The invention relates to the field of bridge engineering, and in particular to a design method for a steel bar oblique interlocking bridge deck connection structure. Background Art

[0002] With the rapid development of my country's transportation industry and the country's vigorous promotion of bridge industrialization, bridge industrialization technology has been vigorously developed and widely used. Various new types of prefabricated and assembled bridges have emerged in large numbers in the engineering field. In the industrial construction of bridges, bridge decks are mostly formed by prefabricated bridge decks using wet joints and post-casting. Prefabricated bridge decks are prefabricated in factories, with anchor steel bars reserved on the edges. The reserved anchor steel bars of two adjacent prefabricated bridge decks are overlapped at the wet joints and then poured with concrete to form a whole. The connection between prefabricated bridge decks plays a restrictive role in the safety of the entire structure. Therefore, the specification puts forward some basic structural requirements for wet joint steel bar overlap. For example, the lap length of the straight steel bar is required to reach a certain multiple of the steel bar diameter length, generally requiring a lap length range of 35d~50d, d is the lap steel bar diameter, and the lap length of the steel bar with a diameter of 20 must reach 700mm~1000mm. The straight lap length requirement is relatively long, which cannot be achieved in many application scenarios, and the construction formwork is also difficult; based on this situation, the engineering and technical personnel changed the reserved steel bars from straight bars to U-shaped rotating steel bars, that is, the upper and lower rows of straight steel bars of the bridge deck are formed by a steel bar through the end hooks. The whole, which can greatly reduce the lap length, because the specification has certain requirements for the bending diameter of the end hook of the steel bar, the bending diameter of the end hook of the ribbed steel bar is required to be at least 5d, and the net bending diameter of the hook of the steel bar with a diameter of 20 is required to reach 100mm. For some thin bridge decks, the steel bar return hook cannot be achieved within the limited thickness range. Excessive bending of the steel bar within the limited thickness range will cause excessive plastic deformation or even yield failure of the steel bar, affecting the bearing characteristics of the steel bar, and it is also difficult to achieve bending in construction. Therefore, it is necessary to propose a new bridge deck reinforcement connection method that is suitable for the current specifications and provide a general design method for this new connection method. Summary of the invention

[0003] In order to solve the problems raised in the above background technology, the present invention provides a design method for a bridge deck connection structure with oblique interlocking steel bars, in order to solve the problem that thin prefabricated bridge deck connection steel bars are difficult to bend. At the same time, a design method is provided to facilitate and quickly calculate the construction requirements, helping designers to make safe and reasonable designs.

[0004] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme:

[0005] The present invention provides a bridge deck connection structure with oblique interlocking of steel bars, which is composed of a first prefabricated bridge deck, a second prefabricated bridge deck and a wet joint. The first prefabricated bridge deck and the second prefabricated bridge deck respectively reserve a certain length of first oblique gate-type steel bars and second oblique gate-type steel bars at a certain inclination angle to the upper and lower planes at the transverse ends of the wet joint, and are arranged at equal intervals along the length direction of the wet joint; the first oblique gate-type steel bars and the second oblique gate-type steel bars are mutually interlocked in an oblique interlocking shape, and a channel of sufficient width is reserved in the middle, and at least 4 longitudinal straight through steel bars vertically penetrate the entire length of the wet joint from the inner peripheral corner of the channel.

[0006] The first reserved steel bars at both ends of the first prefabricated bridge deck in the length direction are L-shaped first lower supplementary steel bars and first upper supplementary steel bars perpendicular to the upper and lower planes, each consisting of a bottom or top straight line segment and a vertical segment at the end of the reserved steel bar;

[0007] The first reserved steel bars at both ends of the second prefabricated bridge deck in the length direction are L-shaped second upper supplementary steel bars and second lower supplementary steel bars perpendicular to the upper and lower planes, and are composed of a bottom or top straight line segment and a vertical segment at the end of the reserved steel bars;

[0008] The first lower supplementary steel bar and the second upper supplementary steel bar are located at the same end in the length direction of the wet joint and are interlocked to form a rectangular ring on the end face of the rectangular channel; the first upper supplementary steel bar and the second lower supplementary steel bar are located at the other same end in the length direction of the wet joint and are interlocked to form a rectangular ring on the other end face of the rectangular channel.

[0009] The present invention also provides a design method for a steel bar oblique interlocking bridge deck connection structure, prefabricating a first prefabricated bridge deck and a second prefabricated bridge deck, and installing and determining the first oblique gate-type steel bar, the second oblique gate-type steel bar, the first lower supplementary steel bar, the first upper supplementary steel bar, the second upper supplementary steel bar, and the second lower supplementary steel bar shape size parameters and steel bar arrangement parameters during the prefabrication;

[0010] The external dimension parameters include the diameter of the steel bar d, the vertical distance H between the two legs of the oblique portal steel bar, and the steel bar arrangement parameters are the distance S between two adjacent steel bars evenly distributed along the length of the wet joint, the distance a from the edge of the wet joint to the center of the opposite reserved steel bar s ;

[0011] The distance a from the edge of the wet joint to the center of the opposite reserved steel bar s The value is greater than 40mm.

[0012] The width B of the wet joint is reserved between the first precast bridge deck and the second precast bridge deck. The second oblique portal steel bar is divided into an upper oblique limb and a lower oblique limb before installation. A gap is left in the middle of the connecting section of the two oblique limbs, so that the first oblique portal steel bar can pass through the gap and interlock with the second oblique portal steel bar in an oblique interlocking shape during installation, and the horizontal lap length l of the first oblique portal steel bar and the second oblique portal steel bar is determined. s After the installation is completed, the upper oblique limb and the lower oblique limb are connected as a whole by using bar welding or mechanical bolt connection to form a complete second oblique gate-type reinforcement;

[0013] The first oblique gate-type steel bar and the second oblique gate-type steel bar are locked with each other to leave a hole in the middle, and the longitudinal straight through steel bar vertically runs through the entire wet joint length from the inner peripheral corner of the hole.

[0014] Furthermore, the horizontal lap length l of the first oblique gate-type steel bar and the second oblique gate-type steel bar s Determine by following these steps:

[0015] 1) Establish the tensile bearing capacity F of the steel bar interlocking bridge deck connection under three failure modes u Calculation method; 2) Calculate the horizontal lap length l of the inclined gate steel bar when each failure mode and steel bar yield failure occur simultaneously si ; 3) Take the calculated l when various working conditions occur si The maximum value is taken as the horizontal lap length l of the first inclined gate-type steel bar and the second inclined gate-type steel bar s Minimum limit value.

[0016] Furthermore, the three failure modes are ① yield failure of connecting steel bars, ② torsion failure of core concrete, and ③ slip failure of steel bars; the calculation method of tensile bearing capacity under each failure mode is as follows;

[0017] 1) The connecting steel bar yields and fails, and the tensile bearing capacity F u1 The calculation formula is:

[0018] F u1 =f y A s =2f y A s1 (1)

[0019] 2) Torsion failure of core concrete refers to the failure mode of overall torsion crushing of the core concrete block surrounded by two bidirectionally interlocked oblique portal steel bars under the asymmetric pressure at both ends. The torsional bearing capacity is provided by the concrete tensile stress on the torsion surface. The torsional bearing capacity T of the core concrete in the torsional failure mode is umax The calculation formula is:

[0020] T umax=0.7W t f t (2)

[0021] Where W t is the torsional plastic resistance moment of the core concrete block surrounded by two bidirectionally interlocked oblique portal steel bars under torsional external force, which is calculated by the following formula:

[0022]

[0023] When the core concrete is torsionally damaged, the torsional bearing capacity T umax The maximum external tensile force, that is, the tensile bearing capacity F u2 The relationship is as follows:

[0024]

[0025] Substituting equations (3) and (4) into equation (2) to solve, we can obtain the tensile bearing capacity F of the core concrete under the torsional failure mode: u2 The calculation formula is:

[0026]

[0027] 3) Steel bar slip failure refers to the failure mode in which the oblique gate-type steel bar is pulled out from the post-cast wet joint concrete. The tensile bearing capacity is controlled by the bond strength between the oblique gate-type steel bar and the surrounding concrete and the compressive stress of the concrete connecting the two limbs of the oblique gate-type steel bar end. The tensile bearing capacity T under the steel bar slip failure mode is u3 The calculation formula is:

[0028]

[0029] In formulas (1)-(6), f y is the design value of tensile strength of connecting steel bars, A s is the total tensile area of ​​a single U-shaped steel bar, A s1 is the single leg area of ​​a single U-shaped steel bar; f c is the design value of compressive strength of wet joint concrete, f t It is the design value of tensile strength of wet joint concrete.

[0030] Furthermore, the horizontal lap length l of the oblique gate-type steel bars is calculated when each failure mode and the steel bar yield failure occur simultaneously. si , refers to the calculation of the material properties of the reserved steel bars and concrete of the prefabricated components, taking the lap length when each failure mode and the steel bar yield failure occur at the same time as the economical and safe lap length; the tensile bearing capacity T under the two failure modes when they occur simultaneously uiThe values ​​are equal, that is, the tensile bearing capacity T under the two combined failure modes ui can be recorded as the same unknown number T u ; Combine equation (1) and equation (5), and equation (1) and equation (6) to obtain the lap length l of the inclined gate-type steel bars under the two working conditions. si ;

[0031] 3) Working condition 1: The core concrete is torsionally damaged and the connecting steel bars are yielded and damaged. The overlapping length l of the oblique gate steel bars is obtained by combining equations (1) and (5) s Denoted as l s1 , as shown below:

[0032]

[0033] 4) Working condition 2: The connecting steel bar yields and fails while the steel bar slips. The overlapping length l of the inclined gate steel bar is obtained by combining equations (1) and (6): s Denoted as l s2 , as shown below:

[0034]

[0035] Furthermore, the calculated l s1 , l s2 Should not be less than 0, if l si If the solution value is less than 0, then take l si =0, finally take l s1 , l s2 The maximum value of is taken as the horizontal lap length l of the first oblique gate-type steel bar and the second oblique gate-type steel bar s The specific calculation formula is as follows:

[0036] l s ≥max{l s1 , l s2} (9).

[0037] Furthermore, the horizontal sections of the first lower supplementary steel bar, the first upper supplementary steel bar, the second upper supplementary steel bar and the second lower supplementary steel bar are reserved for length l a Calculate as follows:

[0038] l a = l s +a s

[0039] Furthermore, the width B of the reserved wet joint is calculated as follows:

[0040] B≥l s +2a s (10).

[0041] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0042] The present invention provides a steel bar oblique interlocking bridge deck connection structure, which utilizes a first oblique gate-type steel bar and a second oblique gate-type steel bar that are obliquely arranged to increase the middle section length of the turned steel bar, increase the bending space of the steel bar, and thus increase the bending radius of the turned steel bar, thereby meeting the requirements of the specification on the bending radius of the steel bar while reducing the plastic deformation of the steel bar, solving the problem that the steel bars of the thin plate structure connection cannot be turned, greatly improving the tensile bearing capacity of the connection compared to straight bars, and also reducing the lap length of the reserved steel bars.

[0043] At the same time, a design method for the connection structure is given, and a method for calculating the bearing capacity of the three possible failure modes of steel bar failure, concrete failure, and sliding failure in the oblique interlocking connection of steel bars is given. The horizontal lap length of the oblique gate-type steel bars when each failure mode and the steel bar yield failure occur simultaneously is calculated as the structural requirement for the steel bar lap length in the connection type. This can achieve simultaneous concrete failure of steel bar failure or sliding failure of steel bar and concrete, so that the bearing capacity of several dimensions of the connection can be maintained at a relatively balanced level, and there will be no problems such as waste of steel bar length or excessive concrete strength. Finally, the maximum lap length calculated under several working conditions is selected as the horizontal lap length of the connecting steel bar, which can ensure that the designed structural dimensions are economical and safe. In summary, the design method provided by the present invention can conveniently and quickly calculate the economical and safe structural requirements for the reserved steel bar lap length of the prefabricated bridge deck, helping designers to make safe and reasonable designs. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 A three-dimensional schematic diagram of a steel bar oblique interlocking bridge deck connection structure of the present invention;

[0046] Figure 2 It is a three-dimensional schematic diagram of the first prefabricated bridge deck of the present invention;

[0047] Figure 3 It is a three-dimensional schematic diagram of a second prefabricated bridge deck of the present invention;

[0048] Figure 4 This is a schematic diagram of the second prefabricated bridge deck of the present invention after cutting a notch;

[0049] Figure 5 This is a schematic diagram of the front elevation of the wet joint connection of the present invention;

[0050] Figure 6 It is a schematic plan view of the wet joint connection of the present invention;

[0051] Figure 7 It is a schematic side cross-sectional view of a wet seam connection according to the present invention;

[0052] Figure 8 The present invention is a flow chart of the connection design method;

[0053] Fig. 9 It is a schematic diagram of the torsional failure mechanics calculation of the core concrete of the present invention;

[0054] Fig.10 The torsional moment distribution diagram of the torsional failure of the core concrete of the present invention along the thickness direction of the wet joint concrete;

[0055] The serial numbers in the above figure are: 1-first precast bridge deck; 2-second precast bridge deck; 3-wet joint; 4-first oblique portal steel bar; 5-first lower supplementary steel bar; 6-first upper supplementary steel bar; 7-second oblique portal steel bar; 7.1-upper oblique limb; 7.2-lower oblique limb; 8-second upper supplementary steel bar; 9-second lower supplementary steel bar; 10-straight through steel bar; 11-gap. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be further described in detail below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention but not all. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0057] like Figure 1-4 The present invention provides a bridge deck connection structure with oblique interlocking of steel bars, which consists of a first prefabricated bridge deck 1, a second prefabricated bridge deck 2, and a wet joint 3; the first prefabricated bridge deck 1 and the second prefabricated bridge deck 2 respectively reserve a certain length of first oblique portal steel bars 4 and second oblique portal steel bars 7 at a certain inclination angle to the upper and lower planes at the transverse ends of the wet joint, and are arranged at equal intervals along the length direction of the wet joint; the first oblique portal steel bars 4 and the second oblique portal steel bars 7 are interlocked with each other in an oblique interlocking shape, and a channel of sufficient width is left in the middle, and four longitudinal straight through steel bars 10 vertically penetrate the entire wet joint length from the inner peripheral corner of the channel.

[0058] like Figure 2-3The first reserved steel bars at both ends of the first prefabricated bridge deck 1 in the length direction are L-shaped first lower supplementary steel bars 5 and first upper supplementary steel bars 6 perpendicular to the upper and lower planes, both of which are composed of a bottom or top straight section and a vertical section at the end of the reserved steel bars; the first reserved steel bars at both ends of the second prefabricated bridge deck 2 are L-shaped second upper supplementary steel bars 8 and second lower supplementary steel bars 9 perpendicular to the upper and lower planes, both of which are composed of a bottom or top straight section and a vertical section at the end of the reserved steel bars; the first lower supplementary steel bars 5 and the second upper supplementary steel bars 8 are located at the same end in the length direction of the wet joint and are interlocked to form a rectangular ring on the end face of the rectangular channel; the first upper supplementary steel bars 6 and the second lower supplementary steel bars 9 are located at the other same end in the length direction of the wet joint and are interlocked to form a rectangular ring on the other end face of the rectangular channel.

[0059] It should be noted that in order to achieve the oblique interlocking shape Figure 1 As shown in the cross shape, it is necessary to cut a gap in the gate-type steel bar before crossing, so that the gate-type steel bar on the other side can be inserted to complete the crossing. After the combination, the gap is welded. In this embodiment, the second oblique gate-type steel bar 7 is cut. Figure 4 :

[0060] The second oblique gate-type steel bar 7 is divided into two parts, an upper oblique limb 7.1 and a lower oblique limb 7.2, before installation. A gap 11 is left in the middle of the connecting section of the two oblique limbs, so that the first oblique gate-type steel bar 4 can pass through the gap 11 to form a two-way interlocking state during installation. After the installation is completed, the upper oblique limb 7.1 and the lower oblique limb 7.2 are connected as a whole by using auxiliary bar welding or mechanical bolt connection to form a complete second oblique gate-type steel bar 7.

[0061] like Figure 1-10 The present invention also provides a design method for a steel bar oblique interlocking bridge deck connection structure:

[0062] The first precast bridge deck 1 and the second precast bridge deck 2 are precast, the concrete grade is C40, and the thickness of the precast bridge deck is 210 mm.

[0063] During prefabrication, the first oblique gate-type steel bar (4), the second oblique gate-type steel bar (7), the first lower supplementary steel bar (5), the first upper supplementary steel bar (6), the second upper supplementary steel bar (8) and the second lower supplementary steel bar (9) are installed and the outer dimension parameters and steel bar arrangement parameters are determined;

[0064] The diameter of the steel bar d is 20mm, the thickness of the wet joint is 210mm, the vertical distance H between the two legs of the oblique gate-type steel bar is 130mm, the distance S between the two adjacent steel bars evenly distributed along the length of the wet joint is 200mm, and the distance a from the edge of the wet joint to the center of the opposite reserved steel bar is s 50mm;

[0065] Find the area of ​​a single leg of a U-shaped steel bar

[0066] A width B of a wet joint is reserved between the first precast bridge deck 1 and the second precast bridge deck 2 .

[0067] The second oblique gate-type steel bar 7 is divided into an upper oblique limb 7.1 and a lower oblique limb 7.2 before installation. A gap 11 is left in the middle of the connecting section of the two oblique limbs, so that the first oblique gate-type steel bar 4 can pass through the gap 11 and interlock with the second oblique gate-type steel bar 7 to form an oblique interlocking shape during installation, thereby determining the horizontal lap length l of the first oblique gate-type steel bar 4 and the second oblique gate-type steel bar 7. s After the installation is completed, the upper oblique limb 7.1 and the lower oblique limb 7.2 are connected as a whole using bar welding or mechanical bolts to form a complete second oblique gate-type steel bar 7.

[0068] The horizontal lap length l of the first oblique gate-type steel bar 4 and the second oblique gate-type steel bar 7 s Determine by following these steps:

[0069] 1) Establish the tensile bearing capacity F of the steel bar interlocking bridge deck connection under three failure modes u Calculation method; 2) Calculate the horizontal lap length l of the inclined gate steel bar when each failure mode and steel bar yield failure occur simultaneously si ; 3) Take the calculated l when various working conditions occur si The maximum value is used as the horizontal lap length l of the first oblique gate-type steel bar 4 and the second oblique gate-type steel bar 7 s Minimum limit value.

[0070] The three failure modes are ① yield failure of connecting steel bars, ② torsion failure of core concrete, and ③ slip failure of steel bars. The calculation method of tensile bearing capacity under each failure mode is as follows;

[0071] 1) The connecting steel bar yields and fails, and the tensile bearing capacity F u1 The calculation formula is:

[0072] F u1 =f y A s =2f y A s1 (1)

[0073] 2) Torsion failure of core concrete refers to the failure mode of overall torsion crushing of the core concrete block surrounded by two bidirectionally interlocked oblique portal steel bars under the asymmetric pressure at both ends. The torsional bearing capacity is provided by the concrete tensile stress on the torsion surface. The torsional bearing capacity T of the core concrete in the torsional failure mode is umax The calculation formula is:

[0074] Tumax =0.7W t f t (2)

[0075] Where W t is the torsional plastic resistance moment of the core concrete block surrounded by two bidirectionally interlocked oblique portal steel bars under torsional external force, which is calculated by the following formula:

[0076]

[0077] In this failure mode, the external tensile force F u2 Under the action, the core concrete block is twisted as a whole along the thickness direction of the wet joint. The torsion changes along the thickness direction, with the maximum at the top and bottom surfaces and zero at the neutral axis. The torsion directions of the upper and lower thickness of the wet joint are opposite. The torsion moment diagram is similar to a parabola shape, with zero at the top and bottom and the maximum in the middle. Therefore, the neutral axis position of the thickness is damaged first and is subjected to the maximum torsion moment, which is the torsional bearing capacity T of the core concrete. umax ; Maximum torque T umax It is generated by the maximum external tensile force and is integrated along the thickness direction, as shown in the following formula:

[0078]

[0079] w(h) is the moment arm of the section torsion at a distance h from the top of the wet joint, calculated by the following formula:

[0080]

[0081] θ is the angle between the inclined portal steel bar and the vertical direction,

[0082] Substituting equation (b) into equation (a) and performing integration operation, we can obtain the torsional bearing capacity T umax The maximum external tensile force, that is, the tensile bearing capacity F u2 The relational expression is as follows:

[0083]

[0084] Substituting equations (3) and (4) into equation (2) to solve, we can obtain the tensile bearing capacity F of the core concrete under the torsional failure mode: u2 The calculation formula is:

[0085]

[0086] 3) Steel bar slip failure refers to the failure mode in which the oblique gate-type steel bar is pulled out from the post-cast wet joint concrete. The tensile bearing capacity is controlled by the bond strength between the oblique gate-type steel bar and the surrounding concrete and the compressive stress of the concrete connecting the two limbs of the oblique gate-type steel bar end. The tensile bearing capacity T under the steel bar slip failure mode is u3 The calculation formula is:

[0087]

[0088] In formulas (1)-(6), f y is the design value of tensile strength of connecting steel bars, A s is the total tensile area of ​​a single U-shaped steel bar, A s1 is the single leg area of ​​a single U-shaped steel bar; f c is the design value of compressive strength of wet joint concrete, f t is the design value of tensile strength of wet joint concrete, l s is the lap length of U-shaped steel bars.

[0089] Calculate the horizontal lap length l of the inclined gate steel bars when each failure mode and steel bar yield failure occur simultaneously si It refers to the calculation of the material properties of the reserved steel bars and concrete of the prefabricated components, taking the overlap length when each failure mode and the steel bar yield failure occur at the same time as the economical and safe overlap length; the tensile bearing capacity T under the two failure modes when they occur at the same time ui The values ​​are equal, that is, the tensile bearing capacity T under the two combined failure modes ui can be recorded as the same unknown number T u ; Combine equation (1) and equation (5), and equation (1) and equation (6) to obtain the lap length l of the inclined gate-type steel bars under the two working conditions. si ;

[0090] 1) Working condition 1: The core concrete is torsionally damaged and the connecting steel bars are yielded and damaged at the same time. The overlapping length l of the oblique gate steel bars is obtained by combining equations (1) and (5). s Denoted as l s1 , as shown below:

[0091]

[0092] 2) Working condition 2: The connecting steel bar yields and fails while the steel bar slips. The overlapping length l of the inclined gate steel bar is obtained by combining equations (1) and (6): s Denoted as l s2 , as shown below:

[0093]

[0094] Take l s1 , ls2 The maximum value of is taken as the minimum limit value of the lap length of the bidirectional cross U-shaped steel bars. The specific calculation formula is as follows:

[0095] l s ≥max{l s1 , l s2}=max{311,142}mm=311mm (10).

[0096] After calculating the minimum limit value of the lap length, the oblique interlocking is completed. A channel is left in the middle of the oblique interlocking of the first oblique gate-type steel bar 4 and the second oblique gate-type steel bar 7. The longitudinal straight through-steel 10 vertically penetrates the entire wet joint length from the inner peripheral corner of the channel.

[0097] Furthermore, the horizontal sections of the first lower supplementary steel bar (5), the first upper supplementary steel bar (6), the second upper supplementary steel bar (8) and the second lower supplementary steel bar (9) are reserved with a length l a Calculate as follows:

[0098] l a = l s +a s =311mm+50mm=361mm (11).

[0099] Here s Take the minimum limit value of 311mm, and reserve the length of the horizontal section l a The result is 361mm.

[0100] Furthermore, the method of the present invention is used to calculate B of the wet joint, as shown in the following formula.

[0101] B≥l s +2a s =311+2×50=411mm (12).

[0102] The above process describes how to calculate the lap length of the reserved steel bars for connecting a certain steel bar oblique interlocking bridge deck and the minimum width of the wet joint using the method of the present invention.

[0103] Comparative Example:

[0104] In order to further illustrate the practical effect of the present invention, this embodiment is described as a comparative example of embodiment 1.

[0105] A post-cast strip is composed of two precast components and their reserved ordinary straight steel bars. The concrete grade is C40, the thickness of the precast component is 210mm, the steel bar diameter d is 20mm, and the distance from the wet joint edge to the opposite steel bar end is a. s The wet joint width is 50mm, and the wet joint width is determined according to the overlap length of the steel bars.

[0106] According to 9.1.9 of the "Design Specifications for Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts" (JTG 3362-2018), the minimum lap length of the steel bar binding should be 40d, that is:

[0107] l s =40×20=800mm,

[0108] Further calculate the minimum width B of the post-cast strip connecting prefabricated components:

[0109] B≥l s +2a s =800+2×50=900mm;

[0110] The lap length and post-casting strip width required for straight steel bar lap connection are much larger than the lap length and wet joint width calculated by the method of the present invention for connecting steel bars with oblique interlocking steel bars, which is difficult to meet in many application scenarios.

[0111] In order to reduce the lap length, the reserved steel bars are changed from straight bars to U-shaped turn bars, that is, the upper and lower rows of straight steel bars of the bridge deck are formed by a steel bar through the end hook. According to the specification requirements, the diameter of the hook at the end of the steel bar is at least 5d, and the steel bar with a diameter of 20 requires the net diameter of the hook to reach 100mm. Then the plate thickness needs to reach: 100+20x2+50x2=240mm, which is greater than the actual plate thickness of this embodiment. The vertical turn hook of the steel bar cannot be realized within the limited thickness range; the connection method of the oblique interlocking of the steel bars by the method of the present invention is adopted, and the net distance between the oblique gate-type steel bar turn hooks is The space requirement of the bend hook is far greater than that required by the specification. Therefore, the method of the present invention can solve the problem that the connecting steel bars of the thin plate structure cannot be turned, and at the same time greatly improve the tensile bearing capacity of the connection and reduce the lap length of the reserved steel bars.

[0112] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A steel bar oblique interlocking bridge deck connection structure, comprising a first prefabricated bridge deck (1), a second prefabricated bridge deck (2), and a wet joint (3), characterized in that: The first prefabricated bridge deck (1) and the second prefabricated bridge deck (2) respectively reserve a certain length of first oblique gate-type steel bars (4) and second oblique gate-type steel bars (7) at a certain inclination angle with the upper and lower planes at the transverse ends of the wet joint, and are arranged at equal intervals along the length direction of the wet joint; the first oblique gate-type steel bars (4) and the second oblique gate-type steel bars (7) are interlocked with each other in an oblique interlocking shape, and a channel of sufficient width is left in the middle, and at least four longitudinal straight through steel bars (10) vertically penetrate the entire length of the wet joint from the inner peripheral corner of the channel.

2. The design method of a steel bar oblique interlocking bridge deck connection structure according to claim 1 is characterized in that: Prefabricate a first prefabricated bridge deck (1) and a second prefabricated bridge deck (2), and simultaneously install and determine the outer dimension parameters and steel bar arrangement parameters of the first oblique gate-type steel bar (4) and the second oblique gate-type steel bar (7); The external dimension parameters include the diameter of the steel bar d, the vertical distance H between the two legs of the oblique portal steel bar, and the steel bar arrangement parameters are the distance S between two adjacent steel bars evenly distributed along the length of the wet joint, the distance a from the edge of the wet joint to the center of the opposite reserved steel bar s ; The distance a from the edge of the wet joint to the center of the opposite reserved steel bar s The value is greater than 40mm; A width B of a wet joint is reserved between the first prefabricated bridge deck (1) and the second prefabricated bridge deck (2). The second oblique gate-type steel bar (7) is divided into two parts, an upper oblique limb (7.1) and a lower oblique limb (7.2) before installation. A gap (11) is left in the middle of the connecting section of the two oblique limbs, so that the first oblique gate-type steel bar (4) can pass through the gap (11) during installation and interlock with the second oblique gate-type steel bar (7) to form an oblique interlocking shape, thereby determining a horizontal overlap length l of the first oblique gate-type steel bar (4) and the second oblique gate-type steel bar (7). s After the installation is completed, the upper oblique limb (7.1) and the lower oblique limb (7.2) are connected as a whole by using bar welding or mechanical bolt connection to form a complete second oblique gate-type steel bar (7); The first oblique gate-type steel bar (4) and the second oblique gate-type steel bar (7) are interlocked with each other to leave a hole in the middle, and the longitudinal straight through steel bar (10) vertically penetrates the entire wet joint length from the inner peripheral corner of the hole.

3. The design method of a steel bar oblique interlocking bridge deck connection structure according to claim 2, characterized in that: The horizontal lap length l of the first oblique gate-type steel bar (4) and the second oblique gate-type steel bar (7) s Determine by following these steps: 1) Establish the tensile bearing capacity F of the steel bar interlocking bridge deck connection under three failure modes u Calculation method; 2) Calculate the horizontal lap length l of the inclined gate steel bar when each failure mode and steel bar yield failure occur simultaneously si ; 3) Take the l calculated when various working conditions occur si The maximum value of is taken as the horizontal lap length l of the first oblique gate-type steel bar (4) and the second oblique gate-type steel bar (7) s Minimum limit value.

4. The design method of a steel bar oblique interlocking bridge deck connection structure according to claim 3, characterized in that: The three failure modes are ① yield failure of connecting steel bars, ② torsion failure of core concrete, and ③ slip failure of steel bars. The calculation method of tensile bearing capacity under each failure mode is as follows; 1) The connecting steel bar yields and fails, and the tensile bearing capacity F u1 The calculation formula is: F u1 =f y A s =2f y A s1 (1) 2) Torsion failure of core concrete refers to the failure mode of overall torsion crushing of the core concrete block surrounded by two bidirectionally interlocked oblique portal steel bars under the asymmetric pressure at both ends. The torsional bearing capacity is provided by the concrete tensile stress on the torsion surface. The torsional bearing capacity T of the core concrete in the torsional failure mode is umax The calculation formula is: T umax =0.7W t f t (2) Where W t is the torsional plastic resistance moment of the core concrete block surrounded by two bidirectionally interlocked oblique portal steel bars under torsional external force, which is calculated by the following formula: When the core concrete is torsionally damaged, the torsional bearing capacity T umax The maximum external tensile force, that is, the tensile bearing capacity F u2 The relationship is as follows: Substituting equations (3) and (4) into equation (2) to solve, we can obtain the tensile bearing capacity F of the core concrete under the torsional failure mode: u2 The calculation formula is: 3) Steel bar slip failure refers to the failure mode in which the oblique gate-type steel bar is pulled out from the post-cast wet joint concrete. The tensile bearing capacity is controlled by the bond strength between the oblique gate-type steel bar and the surrounding concrete and the compressive stress of the concrete connecting the two limbs of the oblique gate-type steel bar end. The tensile bearing capacity T under the steel bar slip failure mode is u3 The calculation formula is: In formulas (1)-(6), f y is the design value of tensile strength of connecting steel bars, A s is the total tensile area of ​​a single U-shaped steel bar, A s1 is the single leg area of ​​a single U-shaped steel bar; f c is the design value of compressive strength of wet joint concrete, f t It is the design value of tensile strength of wet joint concrete.

5. The design method of a steel bar oblique interlocking bridge deck connection structure according to claim 4, characterized in that: Calculate the horizontal lap length l of the inclined gate steel bars when each failure mode and steel bar yield failure occur simultaneously si , refers to the calculation of the material properties of the reserved steel bars and concrete of the prefabricated components, taking the overlap length when each failure mode and the steel bar yield failure occur simultaneously as the economical and safe overlap length, that is, to ensure that when ② the core concrete torsional failure or ③ the steel bar sliding failure occurs, ① the connecting steel bar yield failure occurs at the same time; the tensile bearing capacity T under the two failure modes when they occur simultaneously ui The values ​​are equal, that is, the tensile bearing capacity T under the two combined failure modes ui can be recorded as the same unknown number T u ; Combine equation (1) and equation (5), and equation (1) and equation (6) to obtain the lap length l of the inclined gate-type steel bars under the two working conditions. si ; 1) Condition 1: The core concrete is torsionally damaged and the connecting steel bars are yielding and damaged. The overlapping length l of the oblique gate steel bars is obtained by combining equations (1) and (5). s Denoted as l s1 , as shown below: 2) Working condition 2: The connecting steel bar yields and fails while the steel bar slips. The overlapping length l of the inclined gate steel bar is obtained by combining equations (1) and (6): s Denoted as l s2 , as shown below:

6. The design method of a steel bar oblique interlocking bridge deck connection structure according to claim 5, characterized in that: The calculated l s1 , l s2 Should not be less than 0, if l si If the solution value is less than 0, then take l si =0, finally take l s1 , l s2 The maximum value of is taken as the horizontal lap length l of the first oblique gate-type steel bar (4) and the second oblique gate-type steel bar (7) s The specific calculation formula is as follows: L s ≥max{l s1 ,L s2 } (9) 7. The design method of a steel bar oblique interlocking bridge deck connection structure according to claim 6, characterized in that: The width B of the reserved wet joint is calculated as follows: <h2 style=";text-align:left;direction:ltr">B≥l<h2 style=";text-align:left;direction:ltr"> s <h2 style=";text-align:left;direction:ltr"> +2a<h2 style=";text-align:left;direction:ltr"> s <h2 style=";text-align:left;direction:ltr"> (10)

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