Width and height difference self-adaptive precast beam piece wet joint formwork-free construction structure

Abstract

The utility model discloses a width and height difference self-adaptive prefabricated beam piece wet joint formwork-free construction structure which comprises a beam piece installed on a pier, a cast-in-place joint layer, a joint plate, a pre-buried inverted-U-shaped connecting steel bar, a wing plate steel bar and a transverse connecting steel bar. Wherein the joint plate is of a platform body structure formed by symmetrical corner cutting on the edges of the tops of the two sides of a square concrete prefabricated plate, the bottoms of wing plates of the beam pieces are provided with slope surfaces with the same angle as the corner cutting surfaces of the two sides of the joint plate, the joint plate is arranged in joints between the adjacent beam pieces, and the corner cutting surfaces of the two sides of the joint plate are attached to the slope surfaces of the bottoms of the wing plates of the beam pieces in parallel. The cast-in-place joint layer is poured in a space defined by the joint plate and the beam piece wing plates on the two sides, and the transverse connecting steel bars are connected between the wing plate steel bars on the two sides of the joint and are in lap joint with the inverted-U-shaped connecting steel bars. The utility model solves the problems that the adaptability to the width and height difference change of the wet joint is poor and the construction efficiency is low when the wet joint is constructed by temporarily erecting a bottom die in the traditional method.

Description

Technical Field

[0001] This utility model belongs to the field of bridge construction technology, specifically relating to a precast beam wet joint construction structure that is self-adaptive in terms of pre-width and height difference and requires no formwork support. Background Technology

[0002] Highway engineering, municipal road engineering, and railway engineering commonly involve bridge construction. With the maturation of bridge construction technology, prefabrication is now widely used for small and medium-span bridges. The beams are prefabricated in a prefabrication yard, then transported to the site for installation using bridge erecting machines or cranes. Pre-installed reinforcing bars are then welded or tied on-site, and concrete is poured to form a unified structure from multiple unconnected beams. Wet joints are crucial load-bearing components in prefabricated beam structures and are also weak points during use. Traditional construction methods for wet joints currently suffer from the following problems:

[0003] (1) Traditional wet joints are typically 40cm to 80cm wide. Within this width, steel reinforcement binding or welding can meet structural stress requirements and ensure structural safety. However, due to limitations in the prefabrication accuracy of the beams and the flatness of the pier tops, beams installed in different locations may have certain height differences. Based on the above, in actual construction, the width or height difference of wet joints usually varies, making it difficult to flexibly adapt to these parameter changes in wet joints using the existing method of setting up bottom formwork.

[0004] (2) Currently, the common construction methods for wet joints are suspended construction and various innovative methods based on suspended construction. These methods require the installation of square timber or steel pipes, tie rods, and formwork at the bottom of the wet joint on the beam. After construction, these components need to be removed, which greatly reduces the on-site construction speed and fails to meet the requirements for rapid bridge construction. At the same time, the formwork, square timber, or steel pipes placed on the bridge deck result in poor bridge deck cleanliness, which is not conducive to the finishing and roughening of the bridge deck concrete. The bolt holes formed by the installation of tie rods are difficult to seal, which can easily lead to water leakage on the bridge deck. When removing the formwork, the formwork at the bottom of the wet joint cannot be fixed. The bolts and nuts can only be loosened to allow the formwork to fall freely, which can easily damage the formwork and reduce the number of times the formwork can be reused, thereby increasing construction costs. Utility Model Content

[0005] To address the aforementioned problems, this utility model provides a precast beam wet joint construction structure that adapts to changes in width and height difference without formwork. This solves the problems of poor adaptability and low construction efficiency of traditional methods when constructing wet joints by temporarily erecting bottom formwork.

[0006] This utility model is achieved through the following technical solution.

[0007] A precast beam wet joint formwork-free construction structure with adaptive width and height difference includes beams installed on piers. It is characterized by further comprising a cast-in-place joint layer, a joint plate, inverted U-shaped connecting steel bars embedded in the top of the joint plate, flange steel bars embedded in the sides of the beam's flanges, and transverse connecting steel bars. The joint plate is a platform structure formed by symmetrical chamfering of the top edges of a square precast concrete slab. The bottom of the beam's flange has a slope with the same angle as the chamfered edges on both sides of the joint plate. The joint plate is located within the joint between adjacent beams, and the chamfered surfaces on both sides of the joint plate are parallel and abut against the bottom slope of the beam's flange. The cast-in-place joint layer is poured within the space enclosed by the joint plate and the flanges of both beams. The transverse connecting steel bars connect between the flange steel bars on both sides of the joint and overlap with the inverted U-shaped connecting steel bars.

[0008] Preferably, the joint between the chamfered surface of the joint plate and the slope of the beam flange is filled with a sealant.

[0009] Preferably, the thickness of the chamfered portions on both sides of the joint board accounts for 2 / 3 of the total board thickness.

[0010] Preferably, the chamfer angle on both sides of the joint board is 40° to 60°.

[0011] Preferably, the starting position of the bottom slope of the beam flange is at the position of 1 / 2 of the thickness of the beam flange.

[0012] Preferably, several connecting channels are provided on the chamfered surfaces on both sides of the joint plate along the width direction of the joint plate, and steel mesh is installed in the connecting channels. Several connecting holes corresponding to the connecting channels are vertically opened through the flange of the beam. Steel bars are reserved on the inner wall of the connecting holes, and concrete is poured in the space connecting the connecting holes and the connecting channels.

[0013] Preferably, the present invention also includes vertical connecting steel bars, which are installed in the space where the connecting hole and the connecting channel communicate, and one end of the vertical connecting steel bars is connected to the steel bar head and the other end is connected to the steel mesh.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0015] 1) In this utility model, the joint plate is directly poured together with the concrete at the wet joint to form a whole. This method can reduce the problem of wet joint cracking caused by disturbance from the surrounding environment. As long as the top surface layer is properly maintained and no surface cracks appear, the wet joint can achieve good quality. In particular, this method can eliminate the need for bottom formwork construction, thereby avoiding many problems caused by bottom formwork construction.

[0016] 2) This utility model designs the joint plate as a platform structure with chamfered corners on both sides, and designs the bottom of the beam flange with a slope with the same angle as the chamfered corners on both sides of the joint plate. This allows the chamfered corners of the joint plate to contact the bottom slope of the beam flange parallel during installation. When the joint width or height difference changes, the position of the joint plate can be adjusted by moving it to ensure that the joint plate and the beam fit tightly together. Therefore, this utility model has good applicability to changes in wet joint parameters caused by insufficient beam installation accuracy or construction deviations.

[0017] 3) By setting up connecting channels and connecting holes, and connecting steel mesh and pouring concrete in the space formed by the connection channels and connecting holes, this utility model can improve the overall connection strength between the joint plate and the beams on both sides and enhance the bending resistance between the beams. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the main structure of this utility model;

[0019] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0020] Figure 3 A three-dimensional structural diagram of the beam and joint plate;

[0021] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0022] Figure 5 A schematic diagram showing how to match seam widths to a seam panel;

[0023] Figure 6 A schematic diagram for matching joint boards with different height differences;

[0024] Figure 7 Dimensional design diagram for beam segments and joint plates;

[0025] Figure 8 This is a schematic diagram of the construction of this utility model;

[0026] Figure 9 This is a schematic diagram showing the position control during the hoisting of the joint plate.

[0027] Figure 10 A construction diagram for the installation of the steel mesh frame and the suspension of the joint plate;

[0028] The meanings of the labels in the above figures are as follows: 1. Beam plate; 2. Joint plate; 3. Inverted U-shaped connecting steel bar; 4. Wing plate steel bar; 5. Joint; 6. Support rod; 7. Jack; 8. Horizontal connecting steel bar; 9. Lifting equipment; 10. Connecting channel; 11. Cast-in-place joint layer; 12. Connecting duct; 13. Steel bar end; 14. Vertical connecting steel bar; 15. Steel mesh; 16. Pier; 17. Bridge deck. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that the following embodiments are merely illustrative examples of the present invention, but the scope of protection of the present invention is not limited thereto. The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment provides a precast beam wet joint construction structure that adapts to width and height differences, allowing for formwork-free construction. Please refer to [link / reference]. Figures 1 to 4 The structure includes a cast-in-place joint layer 11, a joint plate 2, an inverted U-shaped connecting steel bar 3 embedded in the top of the joint plate 2, wing plate steel bars 4 embedded in the side of the wing plate of the beam 1, and a transverse connecting steel bar 8. The joint plate 2 is a platform structure formed by symmetrical chamfering of the top edges of the two sides of a square precast concrete slab. The bottom of the wing plate of the beam 1 has a slope with the same chamfer angle as the two sides of the joint plate 2. The joint plate 2 is set in the joint 5 between adjacent beams 1, and the chamfered surfaces on both sides of the joint plate 2 are parallel and attached to the bottom slope of the wing plate of the beam 1. The cast-in-place joint layer 11 is poured in the space enclosed by the joint plate 2 and the wing plates of the two sides of the beam 1. The transverse connecting steel bar 8 is connected between the wing plate steel bars 4 on both sides of the joint 5 and overlaps with the inverted U-shaped connecting steel bar 3.

[0032] To prevent grout leakage during the pouring of the cast-in-place joint layer, in a preferred embodiment, the joint between the chamfered surface of the joint plate 2 and the slope of the flange of the beam 1 is filled with a sealant.

[0033] Furthermore, in a preferred embodiment, the thickness of the chamfered portions on both sides of the joint plate 2 accounts for 2 / 3 of the total plate thickness, the chamfer angle on both sides of the joint plate 2 is 40° to 60°, and the starting position of the bottom slope of the beam slab 1 is at the position of 1 / 2 of the thickness of the beam slab 1.

[0034] Furthermore, in a preferred embodiment, several connecting channels 10 are formed on the chamfered surfaces on both sides of the joint plate 2 along the width direction of the joint plate. A reinforcing mesh 15 is installed within the connecting channels 10. Several connecting holes 12, corresponding one-to-one with the connecting channels 10, are vertically formed through the flanges of the beam 1. Reinforcing bar ends 13 are pre-reserved on the inner wall of the connecting holes 12. Concrete is poured into the space connecting the connecting holes 12 and the connecting channels 10. In addition, the construction structure of this embodiment also includes vertical connecting reinforcing bars 14, which are installed in the space connecting the connecting holes and the connecting channels. One end of the vertical connecting reinforcing bar 14 is connected to a reinforcing bar end, and the other end is connected to the reinforcing mesh. Through the improvement of this embodiment, the overall connection strength between the joint plate and the beams on both sides can be improved, enhancing the bending resistance between the beams.

[0035] Example 2

[0036] To facilitate understanding of this utility model, this embodiment provides a construction method for a precast beam wet joint formwork-free construction structure with adaptive width and height difference. Please refer to [link to relevant documentation]. Figure 8 Specifically, it includes the following steps:

[0037] S1, Prefabrication of components

[0038] Prefabrication of beam 1 and joint slab 2; see below. Figures 3 to 6 The joint plate 2 is a platform structure formed by symmetrical chamfering of the top edges on both sides of a square precast concrete slab. The top of the joint plate 2 is pre-embedded with inverted U-shaped connecting steel bars 3. The bottom of the flange of the beam 1 has a slope with the same chamfering angle as the two sides of the joint plate 2. The flange of the beam 1 is pre-embedded with flange steel bars 4. In order to facilitate construction, the beam 1 and the joint plate 2 are precast in the same precasting site. It is possible to plan a small component precasting site separately in the precasting site of the beam 1 for precasting the joint plate 2. The joint plate 2 is precast using the remaining tailings from the casting of the beam 1. When the joint plate 2 is cast, due to its relatively thin structure design, the time and intensity of vibration should be controlled. After casting, the top should be roughened or roughened to strengthen the connection between the subsequent cast-in-place joint or bridge deck pavement and the joint plate. After the joint plate is precast, it can be transported by vehicles or machinery such as forklifts and cranes and stored together with the beam.

[0039] In this embodiment, please refer to Figure 7The prefabrication parameters of beam 1 and joint plate 2 are as follows: Let the top width of joint plate 2 be a, the bottom width be b, the plate thickness be h, and the chamfer angle be β; let the thickness of the flange of beam 1 be H, the width be L; let the width of joint 5 be X; and let the height difference of joint 5, i.e., the height difference between the beams on both sides of the joint, be Y. All dimensions are in cm. The thickness of the chamfered portion on both sides of joint plate 2 accounts for 2 / 3 of the total plate thickness, while the remaining bottom 1 / 3 maintains a square structure. This structural design facilitates demolding during construction and protects the finished product from damage during transportation and installation. The starting position of the bottom slope of the flange of beam 1 is at 1 / 2 the thickness of the flange to ensure the structural strength of the flange end. At this point, the parameters of joint plate 2 and flange of beam 1 have the following relationship:

[0040]

[0041] Please see Figure 5 and Figure 6 Since the chamfer angles on both sides of the joint plate 2 are the same as the slope angle at the bottom of the flange of the beam 1, the chamfered surface of the joint plate 2 is in parallel contact with the bottom slope of the flange of the beam 1 during installation. When the joint width X or the height difference Y changes, the position of the joint plate 2 can be adjusted by moving it so that the joint plate 2 and the beam 1 fit together tightly. It can be calculated that the theoretical joint width X applicable to the joint plate 2 is (a-2L, b). However, the minimum value a-2L and the maximum value b of this range are the critical positions of the contact between the joint plate 2 and the beam 1. In actual use, it is necessary to ensure that the horizontal contact width between the chamfered surfaces on both sides of the joint plate 2 and the bottom slope of the flange of the beam 1 is not less than 2cm. So, in fact, the theoretical joint width X applicable to the joint plate 2 is (a-2L+4, b-4), that is, the appropriate joint width is a-2L+4 and the maximum value is b-4. Substituting equations (1) and (2) into the equations, we can see that:

[0042] The theoretical joint width X applicable to the joint board (2) is within the following range:

[0043]

[0044] The theoretical range of variation for the joint width X applicable to the joint board (2) is as follows:

[0045]

[0046] Considering that the horizontal contact width between the chamfered surfaces on both sides of the joint plate 2 and the bottom slope of the flange of beam 1 is not less than 2cm, the range of the theoretical joint height difference Y applicable to the joint plate 2 can also be calculated as follows: Right now:

[0047] Y min =0

[0048]

[0049] The theoretical range of variation for the joint height difference Y applicable to joint plate 2 is as follows:

[0050]

[0051] To reduce the weight of the precast slab and facilitate construction, the thickness h of the joint plate 2 should not be too large. In this embodiment, the thickness h of the joint plate 2 is taken as 5-8 cm. The thickness H of the flange of the beam 1 is determined according to the construction requirements. Therefore, in actual engineering, the thickness h of the joint plate 2 and the thickness H of the flange of the beam 1 are fixed values. Combining equations (3) and (4), it can be seen that the maximum theoretical joint width X applicable to the joint plate 2 is... max and minimum value X min Related to the top width 'a' and the chamfer angle 'β' of joint plate 2, and combined with equation (5), it can be seen that the theoretical range of joint width applicable to joint plate 2 is... △ X is only related to the chamfer angle β, and is negatively correlated with the chamfer angle β; combined with equation (6), it can be seen that the maximum theoretical joint height difference Y applicable to joint plate 2 is max Related to the chamfer angle β, combined with equation (7), it can be seen that the theoretical range of joint height difference applicable to joint plate 2 is... △ Y is only related to the chamfer angle β, and is positively correlated with the chamfer angle β. The chamfer angle β of the joint plate 2 will simultaneously affect the theoretical joint width and height difference range applicable to the joint plate 2, and the former is negatively correlated while the latter is positively correlated. Therefore, in order to take into account the changes in joint width and height difference, the chamfer angle β in this embodiment is taken as 40° to 60°.

[0052] S2, Beam installation

[0053] The beam segment 1 was installed on the pier 16 using conventional methods;

[0054] S3, Joint plate hoisting

[0055] Since the joint plate needs to be installed below the joint, but the joint plate is wider than the joint, the lifting equipment 9 is used to vertically lift the joint plate 2 along the length of the beam 1 from one side of the joint 5, keeping the joint plate 2 horizontal and 1-1.5m below the beam 1. Then, the joint plate 2 is longitudinally moved to directly below the joint 5 so that the joint plate 2 can pass safely and smoothly from the side of the joint 5. After adjusting the lateral position of the joint plate 2, the joint plate 2 is slowly lifted vertically so that the chamfered surfaces on both sides of the joint plate are in contact with the slope of the bottom of the beam wing plate. At this time, it should be ensured that the beam wing plate is not under force or is only under a small force from the joint plate to prevent the beam 1 from being disturbed by the joint plate and shifting its installation position. At this time, the joint plate is only temporarily suspended below the joint by the lifting equipment to complete the initial positioning of the joint plate, but the joint plate is not fixed and stable.

[0056] Please see Figure 9 In this process, since the position of the beam segment is determined after installation, and the joint width X and height difference Y are also determined, the joint plate 2 has only one installation position where the chamfered surface of the joint plate 2 is parallel and fits against the bottom slope of the flange of the beam segment 1. The lateral position of the joint plate 2 can be determined by the horizontal distance Z between the vertical centerline of the joint plate 2 and the side of the flange of the higher beam segment 1, and calculated by the following formula:

[0057]

[0058] Where X is the joint width, Y is the joint height difference, and β is the chamfer angle;

[0059] In this step, a layer of asphalt less than 0.5cm thick can be applied to the chamfered surfaces on both sides of the joint plate 2 before lifting the joint plate 2. This can buffer the impact or friction between the chamfered surfaces on both sides of the joint plate and the slope at the bottom of the beam flange when the joint plate is lifted or its position is adjusted. Secondly, after the stress conversion is completed in the subsequent step S4, the chamfered surfaces on both sides of the joint plate can fit tightly with the slope at the bottom of the beam flange and achieve a seal, so as to prevent grout leakage and water seepage on the bridge deck during joint pouring.

[0060] S4, Joint Board Suspension

[0061] Please see Figure 10 The support rod 6 is inserted horizontally through the inside of the inverted U-shaped connecting steel bar 3, with both ends of the support rod 6 overlapping the flanges of the beam 1 on both sides of the joint. A jack 7 is installed between the end of the support rod 6 and the flange of the beam 1, and then the jack 7 is slowly and synchronously lifted, so that the joint plate 2 is suspended and supported in the joint 5 between the adjacent beam 1 through the cooperation of the support rod 6 and the jack 7, and the lifting equipment is relieved of the stress, thus completing the stress conversion. At this time, the lifting rope can be removed and the relevant lifting equipment can be released. The joint plate will be stably fixed in the joint 5, and the chamfered surfaces on both sides of the joint plate will fit tightly against the slope of the bottom of the beam flange. In this step, the support rod 6 is a steel pipe, and the jack 7 is a self-locking hydraulic jack. The inverted U-shaped connecting steel bar 3 should be pre-embedded with an appropriate length in step S1 so that after the joint plate 2 is initially fixed in step S3, there is space between the top of the inverted U-shaped connecting steel bar 3 and the beam flange for the jack 7 and the support rod 6 to work together.

[0062] S5. Installation of steel mesh frame

[0063] Please see Figure 2Transverse connecting bars 8 are connected between the flange reinforcing bars 4 on both sides of the joint 5, and the transverse connecting bars 8 are overlapped with the inverted U-shaped connecting bars 3 at the transverse position, so that the flange reinforcing bars 4, the inverted U-shaped connecting bars 3 and the transverse connecting bars 8 are connected to form an integral steel mesh; at this time, the joint plate 2 is connected to the beams on both sides through the steel mesh to form an integral structure, and under the connection and fixing action of the steel mesh and the cooperation and fixing of the jacks 7 and the support rods 6, it can provide stable force support for subsequent joint pouring;

[0064] S6, Joint Pouring

[0065] Foaming materials such as foam adhesive or polyurethane foaming agent are used as sealants to seal the joint between the chamfered surface of the joint plate 2 and the slope of the wing plate of the beam 1 to prevent grout leakage during pouring. Then, concrete of the same grade as the beam slab is used to pour the cast-in-place joint layer 11 in the space enclosed by the joint plate 2 and the wing plates of the beam 1 on both sides, and cover it with a membrane for regular curing. After the strength of the cast-in-place joint layer 11 reaches the required level, the support rods 6 and jacks 7 are removed. The inverted U-shaped connecting steel bars 3 exposed outside the cast-in-place joint layer 11 can be cut to a suitable length to overlap with the steel bars of the bridge deck surface layer. After that, the subsequent paving construction of the bridge deck 17 can be carried out.

Claims

1. A formwork-free construction structure of a precast beam piece wet joint with adaptive width and height difference, comprising a beam piece installed on a pier, characterized in that, The cast-in-place joint layer, the joint plate, the inverted U-shaped connecting steel bars embedded on the top of the joint plate, the wing plate steel bars embedded on the side of the wing plate of the beam piece, and the transverse connecting steel bars are further included.

2. The construction structure of claim 1, wherein, The cutout surface of the joint plate and the slope surface of the wing plate of the beam piece are filled with a sealing agent.

3. The construction structure of claim 1, wherein, The thickness of the cutout portion on the two sides of the joint plate accounts for 2 / 3 of the thickness of the whole plate.

4. The cast-in-place construction structure of claim 1, wherein, The angle of the cutout on the two sides of the joint plate is 40°-60°.

5. The self-clamping formwork-free construction structure for the wet joint of precast beam segments with adaptive width and height difference according to claim 1, characterized in that, The starting position of the slope surface on the bottom of the wing plate of the beam piece is at the position of 1 / 2 of the thickness of the wing plate of the beam piece.

6. The self-clamping formwork-free construction structure for the wet joint of precast beam segments with adaptive width and height difference according to claim 1, characterized in that, A plurality of connecting grooves are formed on the cutout surface on the two sides of the joint plate along the width direction of the joint plate, and a steel bar mesh is installed in the connecting grooves.

7. The cast-in-place construction structure of claim 6, wherein the width and height difference adaptive precast beam piece wet joint is characterized in that, A plurality of connecting holes corresponding to the connecting grooves are vertically formed through the wing plate of the beam piece, and a steel head is reserved on the inner wall surface of the connecting holes. The space in which the connecting holes and the connecting grooves are communicated is filled with concrete. The vertical connecting steel bars are installed in the space in which the connecting holes and the connecting grooves are communicated, and one end of the vertical connecting steel bars is connected with the steel head and the other end is connected with the steel bar mesh.

Images