Bridge side span post-cast strip-free cast-in-place formwork system and construction method thereof

Abstract

The invention relates to the technical field of bridge construction, and provides a bridge side span post-cast strip-free cast-in-place formwork system and a construction method thereof.The bridge side span post-cast strip-free cast-in-place formwork system comprises a formwork mechanism and a connecting mechanism; the formwork mechanism comprises a temporary support, and the temporary support is arranged between the main span buttress and the side span buttress in a supported mode. A first support is fixed to the top of the temporary support, the two ends of the first support extend to the bottom of the main span section and the position above the side span buttress correspondingly, a second support is arranged above the first support in a supported mode, and the first support is in sliding fit with the second support through a sliding pair; a side span template is mounted and fixed on the second support; the side span template piece is used for pouring a side span section; the connecting mechanism is installed at the bottom of the main span section and connected with the end, close to the main span section, of the second support. The method has the effect that the main span section and the side span sections are integrally constructed.

Description

Technical Field

[0001] This application relates to the technical field of bridge construction, and in particular to a formwork system and construction method for cast-in-place formwork without post-cast strips for bridge side spans. Background Technology

[0002] In bridge construction, after the main span is rotated, the side spans often need to be cast in place to connect with the main span. Since the formwork for the side spans is usually fixed to the existing structure and temporary supports, these structures provide rigid constraints. During actual casting, factors such as nighttime temperature drops cause significant shrinkage deformation in the concrete structure of the side spans. This easily generates large tensile stresses at the interface between the main span and the side span, leading to cracks. To limit crack formation, traditional construction methods typically involve a post-cast strip between the main span and the side span. After the side span is cast, this strip is then cast to connect the main span and the side span.

[0003] Regarding the aforementioned technologies, the construction of the post-cast strip between the main span and the side span requires a second formwork erection after the side span is poured. The overall process is quite complicated and the construction period is long. In addition, the setting of the post-cast strip also indirectly affects the connection and integration between the main span and the side span. Therefore, there is room for improvement. Summary of the Invention

[0004] In order to facilitate the integrated casting construction of the side span while limiting the generation of cracks at the junction of the main span and the side span, this application provides a bridge side span cast-in-place formwork system and construction method without post-cast strip.

[0005] This application provides a bridge side span cast-in-place formwork system and construction method without post-cast strips, which adopts the following technical solution:

[0006] A formwork system for cast-in-place bridge side spans without post-cast strips includes a formwork mechanism and a connection mechanism;

[0007] The template mechanism includes a temporary support frame, which is erected between the main span pier and the side span pier. A first support is fixed to the top of the temporary support frame, and the two ends of the first support frame extend to the bottom of the main span section and the top of the side span pier, respectively. A second support frame is erected above the first support frame, and the first support frame slides into the second support frame via a sliding pair. A side span template is installed and fixed on the second support frame. The side span template frame is used for casting the side span section.

[0008] The connecting mechanism is installed at the bottom of the main span and is connected to the end of the second support near the main span.

[0009] By adopting the technical scheme, the sliding pair is arranged between the first support and the second support, so that the second support and the side span form can slide relative to the first support; when the subsequent pouring of the concrete structure into the side span form causes shrinkage deformation due to temperature reduction, and tensile stress is generated between the side span section and the main span section, the second support and the side span form can displace relative to the first support in the direction of the main span section under the action of the shrinkage of the concrete, so as to actively release the tensile stress and limit the generation of cracks at the joint surface between the main span section and the side span section. Compared with the traditional construction method, the generation of cracks between the main span section and the side span section can be limited without setting a post-pouring belt, the one-time integral pouring of the side span concrete is realized, and the construction efficiency is effectively improved. The main span section and the second support are connected by the connecting mechanism, the second support is limited by the connecting mechanism, so that the second support can better drive the side span form to move towards the main span section when the subsequent concrete structure shrinks and deforms.

[0010] Preferably, the sliding pair comprises a plurality of support steel bars, and the plurality of support steel bars are laid on the top of the first support along the length direction of the first support, and the bottom of the second support abuts on the plurality of support steel bars.

[0011] By adopting the technical scheme, the low-friction linear sliding track for the second support to slide is formed by the plurality of rolling support steel bars, the frictional resistance between the second support and the first support is effectively reduced, and the second support can move more smoothly towards the main span section when the subsequent concrete structure shrinks and deforms to generate tensile stress, so as to balance the tensile stress generated by the shrinkage and deformation of the concrete structure.

[0012] Preferably, a limiting frame is arranged on the top of the first support corresponding to the plurality of support steel bars, the plurality of support steel bars are located in the limiting frame, and the top of the support steel bar protrudes from the upper surface of the limiting frame.

[0013] By adopting the technical scheme, the plurality of support steel bars are limited by the limiting frame, so that the support steel bars can stably roll in the limiting frame when the second support moves relative to the first support, the displacement or falling of the support steel bars is effectively limited, the stability and reliability of the sliding pair are ensured, and the smooth sliding of the second support is facilitated.

[0014] Preferably, the sliding pair comprises a PTFE plate, the PTFE plate is laid on the top of the first support along the length direction of the first support, and the bottom of the second support abuts on the PTFE plate.

[0015] By adopting the technical scheme, the frictional resistance between the first support and the second support is effectively reduced by the PTFE plate, and the second support can move more smoothly towards the main span section when the subsequent concrete structure in the side span form shrinks and deforms to generate tensile stress, so as to balance the tensile stress generated by the shrinkage and deformation of the concrete structure.

[0016] Preferably, the connecting mechanism comprises a plurality of connecting seats embedded in the bottom of the main span section, a through jack is installed on each of the connecting seats, a steel strand is tensioned on each of the through jacks, and each of the steel strands is connected to one end of the second support near the main span section.

[0017] By adopting the above technical scheme, the through jack fixed on the bottom of the main span section cooperates with the steel strand to pull and limit the second support and the side span formwork, so that when the subsequent concrete structure in the side span formwork shrinks and deforms to generate tensile stress, the second support and the side span formwork can more stably move towards the direction of the main span section to balance the tensile stress generated when the concrete structure shrinks.

[0018] Preferably, a plurality of limiting rods are vertically arranged on opposite sides of the first support, and the second support is located between the limiting rods on the opposite sides of the first support.

[0019] By adopting the above technical scheme, the limiting rods arranged on the two sides of the first support form a guide limiting structure to guide and limit the second support, so as to limit the lateral deviation or torsion of the second support in the subsequent sliding process, effectively improving the stability and accuracy of the sliding process of the second support.

[0020] Preferably, a limiting jack is arranged on the top of each of the limiting rods, and the limiting jack is arranged towards the second support.

[0021] By adopting the above technical scheme, after the second support is installed and positioned, the limiting jack drives its piston rod to abut against the outside of the second support to limit the second support, so as to limit the displacement of the second support through the sliding pair when the side span formwork installation and the steel bar binding operation are performed on the second support. After the subsequent concrete pouring construction of the side span section is completed, the limiting jack drives its piston to retract and reset, so that the second support and the side span formwork can move towards the main span section when the concrete structure shrinks and deforms, so as to balance the tensile stress generated by the shrinkage and deformation of the concrete structure.

[0022] Preferably, a construction method of the bridge side span without post-pouring strip cast-in-place formwork system comprises the following steps:

[0023] S1: temporary support arrangement: a temporary support is arranged between the main span support pier and the side span support pier;

[0024] S2: first support arrangement: a first support is installed and fixed on the top of the temporary support;

[0025] S3: sliding pair installation: a sliding pair is installed on the top of the first support;

[0026] S4: second support arrangement: a second support is installed and fixed on the top of the sliding pair;

[0027] S5: connecting mechanism installation: installing the connecting mechanism at the bottom of the main span section, and connecting the connecting mechanism with the second support near one end of the main span section;

[0028] S6: side span formwork installation: installing the side span formwork for pouring the side span section on the second support.

[0029] By adopting the above technical scheme, when the concrete structure poured in the side span section subsequently shrinks due to temperature reduction and generates tensile stress at the joint surface of the main span section and the side span section, the second support and the side span formwork can move towards the main span section through the sliding pair, which is beneficial to balance the tensile stress generated by the shrinkage deformation of the concrete structure of the side span section and limit the generation of the gap between the main span section and the side span section.

[0030] In summary, the present application includes at least one of the following beneficial technical effects:

[0031] 1. By setting the sliding pair between the first support and the second support, when the concrete poured in the side span formwork subsequently shrinks due to temperature reduction, the second support can be driven by the sliding pair to displace the side span formwork relative to the first support towards the direction of the main span section under the shrinkage force of the concrete structure, effectively balancing the tensile stress generated by the shrinkage of the concrete structure, without the need to set a post-pouring belt, so as to limit the situation that cracks appear at the joint surface of the side span section and the main span section due to the tensile stress generated by the shrinkage of the concrete structure of the side span section, realize one-time pouring construction of the side span section, and effectively improve the overall construction efficiency.

[0032] 2. By supporting the limiting frame on the first support and laying the supporting steel bar in the limiting frame, the stable linear track is formed by the supporting steel bar cooperating with the limiting frame, which is beneficial to smoothly move the second support towards the main span section under the shrinkage force of the concrete.

[0033] 3. By vertically supporting the limiting rods on the opposite sides of the first support and supporting the limiting oil cylinder on the top of the limiting rod, the second support is limited by the limiting rod to limit the transverse movement of the second support, and after the second support is installed in place, the second support can be temporarily limited by the limiting oil cylinder to limit the displacement of the second support which affects the construction when the side span formwork is installed and the concrete is poured. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structural schematic view of the cast-in-place formwork system of embodiment one.

[0035] Figure 2 is a structural schematic view of the connecting mechanism of embodiment one.

[0036] Figure 3 is a state schematic view of the installation of the sliding pair of embodiment one.

[0037] Figure 4 is Figure 1 A enlarged schematic view of the middle part.

[0038] Figure 5 is a schematic view for showing the state of installing the sliding pair.

[0039] Explanation of reference signs:

[0040] 1, main span support pier; 10, main span section; 2, side span support pier; 3, temporary support; 4, first support; 41, limiting rod; 42, limiting jack; 5, second support; 6, limiting frame; 61, supporting steel bar; 62, Teflon plate; 7, side span formwork; 8, connecting seat; 80, connecting ring; 81, through-jack; 82, steel strand. DETAILED DESCRIPTION

[0041] The following will be described in detail with reference to the accompanying Figures 1-5 The present application is further described in detail.

[0042] The embodiment of the present application discloses a bridge side span no post-pouring band cast-in-place formwork system and a construction method thereof.

[0043] The bridge side span no post-pouring band cast-in-place formwork system, referring to Figure 1 and Figure 2 , comprises a formwork mechanism and a connecting mechanism, the formwork mechanism comprises a temporary support 3, the temporary support 3 is arranged between the main span support pier 1 and the side span support pier 2. The first support 4 is fixed at the top of the temporary support 3, and the two ends of the first support 4 extend to the bottom of the main span and above the side span support pier 2 respectively. The second support 5 is arranged above the first support 4, and the second support 5 is in sliding cooperation with the first support 4 through a sliding pair. The side span formwork 7 is fixedly installed on the second support 5, and the side span formwork 7 is used for pouring the side span section; one end of the side span formwork 7 close to the main span section 10 extends and is attached to the end of the main span section 10, and the other end of the side span formwork 7 away from the main span section 10 is blocked. The connecting mechanism is installed at the bottom of the main span section 10, and the connecting mechanism is connected to one end of the second support 5 close to the main span section 10, and the connecting mechanism is used for connecting and limiting the second support 5 and the side span formwork 7.

[0044] After the subsequent steel bar structure and concrete structure are bound and poured inside the side span formwork 7, when the subsequent concrete structure shrinks and deforms to the middle part of the formwork due to cooling, the second support 5 can drive the side span formwork 7 to displace relative to the first support 4 in the direction of the main span section 10 under the shrinkage force of the concrete structure through the sliding pair, so as to release the tensile stress generated on the combined surface of the side span section and the main span section 10 due to the shrinkage of the concrete, and further limit the generation of cracks on the combined surface of the side span section and the main span section 10.

[0045] Referring to Figure 1 and Figure 2In the embodiment, the temporary support 3 adopts an existing steel pipe pile support, the first support includes a plurality of parallel arranged double-spliced I-beams, the adjacent double-spliced I-beams are connected through a plurality of connecting rods, the second support 5 has the same structure as the first support 4, and thus will not be described again.

[0046] With reference to Figure 1 and Figure 3 , the sliding pair includes a limiting frame 6 and a plurality of support steel bars 61, the limiting frame 6 is fixed on the first support 4, the plurality of support steel bars 61 are laid on the top of the first support 4 along the length direction of the first support 4, and the plurality of support steel bars 61 are all located in the limiting frame 6, the top of the support steel bar 61 is protruded from the upper surface of the limiting frame 6, and the second support 5 abuts on the plurality of support steel bars 61. The sliding cooperation between the second support 5 and the first support 4 is realized. In the actual construction process, butter can be smeared on the outer periphery of the support steel bar 61 to further reduce the friction between the support steel bar 61 and the second support 5.

[0047] With reference to Figure 1 and Figure 2 , the connecting mechanism includes a connecting seat 8 fixed on the bottom of the main span section 10, a plurality of through jacks 81 are installed on the connecting seat 8, and the plurality of through jacks 81 are all arranged towards the second support 5; a plurality of connecting rings 80 are welded on the end of the second support 5 corresponding to the plurality of through jacks 81, and the steel strands 82 are all tensioned on the through jacks 81, and the ends of the steel strands 82 away from the through jacks 81 are all connected and fixed with the end connecting rings 80 of the second support 5, so as to realize the traction limiting of the second support 5.

[0048] With reference to Figure 1 and Figure 4 , the first support 4 is vertically provided with a plurality of limiting rods 41 on the opposite sides, the limiting rods 41 are welded on the side edges of the first support 4, and the second support 5 is located between the limiting rods 41 on the opposite sides of the first support 4. The limiting rods 41 on the opposite sides of the first support 4 are used for limiting the second support 5, so as to limit the transverse displacement of the second support 5 in the subsequent construction process, which is beneficial to the stable movement of the second support 5 towards the direction of the main span section 10 in the subsequent concrete shrinkage deformation, so as to balance the tensile stress generated in the concrete shrinkage deformation. At the same time, the limiting rods 41 on the opposite sides of the first support 4 are used for limiting and guiding the second support 5 when the second support 5 is installed, so as to accurately install the second support 5 in place.

[0049] With reference to Figure 1 and Figure 4The top of each limiting rod 41 is vertically provided with a limiting jack 42, the limiting jack 42 is located outside the limiting rod 41 and faces the second support 5. The piston rod of the limiting jack 42 is arranged in the limiting rod 41. After the second support 5 is installed on the sliding pair, the piston rod is driven to abut against the outside of the second support 5 through the limiting jack 42 at the top of each limiting rod 41, so as to temporarily limit and fix the second support 5 through the limiting jack 42, so as to limit the displacement of the second support 5 during the subsequent operation of supporting the side span formwork 7 on the second support 5 and pouring concrete, and thus affect the safety of the operation. After the concrete pouring operation is completed, the piston rod is driven to retract and reset through the limiting jack 42, so as to release the limiting of the second support 5, so that the second support 5 can drive the side span formwork 7 to move towards the direction of the main span section 10 when the concrete structure shrinks and deforms.

[0050] A construction method of a bridge side span without post-pouring band cast-in-place formwork system, referring to Figures 1 to 4 , comprising the following steps:

[0051] S1: temporary support 3 is supported: the temporary support 3 is supported between the main span support pier 1 and the side span support pier. During construction, the levelness and perpendicularity of the temporary support 3 are ensured by cooperating with a total station and other measuring tools to ensure the stability thereof.

[0052] S2: the first support 4 is supported: the first support 4 is supported on the top of the temporary support 3; the specific steps are as follows:

[0053] S2.1: the first support 4 is assembled in advance;

[0054] S2.2: the first support 4 is installed in place: the first support 4 is hoisted to the top of the temporary support 3, and the two ends thereof extend above the main span bottom and the side span support pier 2 respectively;

[0055] S2.3: the first support 4 is connected with the temporary support 3 by means of pre-buried bolts or welding;

[0056] S2.4: the limiting rod 41 is installed: a plurality of limiting rods 41 are welded and fixed on the opposite sides of the first support 4;

[0057] S2.5: the limiting jack 42 is installed: the limiting jack 42 is vertically installed at the top of the limiting rod 41;

[0058] S3: the sliding pair is installed: the sliding pair is installed on the top of the first support 4; the specific steps are as follows:

[0059] S3.1: the limiting frame 6 is installed: the limiting frame 6 is hung on the first support 4, and the limiting frame 6 is welded and fixed with the first support 4;

[0060] S3.2: Pre-coat butter on the outer periphery of the supporting steel bars 61;

[0061] S3.3: Lay the supporting steel bars 61 into the limiting frame 6 and ensure that the supporting steel bars 61 are arranged in order.

[0062] S4: Second support 5 setting: The specific steps are as follows:

[0063] S4.1: Assemble the second support 5 in advance;

[0064] S4.2: Second support 5 installation: Hoist the second support 5 above the sliding pair and make the second support 5 abut on the several supporting steel bars 61 inside the limiting frame 6;

[0065] S4.3: Second support 5 temporary limiting: Drive the piston rod of the limiting oil cylinder at the top end of the limiting rod 41 to abut on the side surface of the second support 5 to limit and fix the second support 5.

[0066] S5: Connection mechanism installation: The specific steps are as follows:

[0067] S5.1: Install the fixed connection seat 8 at the bottom of the end of the main span section 10;

[0068] S5.2: Install the through jack 81 on the connection seat 8 and make the through jack 81 face the second support 5;

[0069] S5.3: Weld the connection ring 80 near the end of the one end of the second support 5 close to the main span section 10;

[0070] S5.4: Pass the steel strand 82 through the through jack 81 and fix the steel strand 82 on the connection ring 80 at the end of the second support 5 through the rope clamp; tighten the steel strand 82 through the through jack 81.

[0071] S6: Side span formwork 7 installation: Install the fixed side span formwork 7 on the second support 5; The specific steps are as follows:

[0072] S6.1: Support the fixed side span formwork 7 bottom form on the second support 5;

[0073] S6.2: Support the side span formwork 7 side form on both sides of the side span formwork 7 bottom form;

[0074] S6.3: Support the fixed side span formwork 7 end form on the side span formwork 7 bottom form away from the one end of the main span section 10.

[0075] S7: Side span section steel bar operation: Bind the side span section steel bar structure in the side span formwork 7 and fix the steel bar structure with the main span section 10 reserved steel bar joint;

[0076] S8: Pouring concrete for side span section: pouring concrete in the side span formwork 7 to form the side span section;

[0077] S9: Unblocking the side span section: retracting the piston rod of the limiting oil cylinder at the top end of the limiting rod 41 to unblock the second support 5.

[0078] Example Two

[0079] Example Two differs from Example One in that: Figure 1 and Figure 5 The sliding pair includes a Teflon plate 62, which is fixed to the top of the second support 5 and abuts the bottom of the second support 5. The Teflon plate 62 effectively reduces the friction between the second support 5 and the first support 4, allowing the second support 5 to move smoothly along the first support 4 towards the main span section 10 when the side span section concrete structure shrinks and deforms, thereby balancing the concrete tensile stress at the junction between the side span section and the main span section 10 when the side span section concrete structure shrinks and deforms. In other embodiments, the Teflon plate 62 can be replaced by a stainless steel plate.

[0080] The construction method of the bridge side span post-cast strip cast-in-place formwork system in Example Two differs from Example One in that:

[0081] S3: Installing the sliding pair on the top of the first support 4; the specific steps are as follows:

[0082] S3.1: Installing the Teflon plate 62: hoisting the Teflon plate 62 onto the first support 4 and connecting the Teflon plate 62 and the first support 4 through bolt and nut cooperation.

[0083] S4: Setting up the second support 5; the specific steps are as follows:

[0084] S4.1: Assembling the second support 5 in advance;

[0085] S4.2: Installing the second support 5 in place: hoisting the second support 5 above the sliding pair and abutting the second support 5 to the surface of the Teflon plate 62;

[0086] S4.3: Temporarily blocking the second support 5: abutting the piston rod of the limiting oil cylinder at the top end of the limiting rod 41 to the side of the second support 5 to block and fix the second support 5.

[0087] The application sets a sliding pair between the second support 5 and the first support 4, so that the second support 5 and the side span formwork 7 can slide along the first support 4. When the concrete structure of the subsequent side span segment deforms due to shrinkage and generates a concrete tensile stress at the joint surface of the main span segment 10 and the side span segment, the second support 5 and the side span formwork 7 move in the direction relative to the first support 4 and towards the main span segment 10, so as to balance the tensile stress. Compared with the traditional construction method, the post-pouring segment does not need to be set, and the cracking phenomenon between the main span segment 10 and the side span segment can be limited, and the overall construction efficiency is effectively improved.

[0088] The above are preferred embodiments of the application, which do not limit the protection scope of the application. Any equivalent changes made on the basis of the structure, shape and principle of the application should be covered by the protection scope of the application.

Claims

1. A formwork system for cast-in-place construction without post-cast strips in bridge side spans, characterized in that: Includes template mechanism and connecting mechanism; The template mechanism includes a temporary support (3), which is supported between the main span pier (1) and the side span pier (2); a first support (4) is fixed to the top of the temporary support (3), and the two ends of the first support (4) extend to the bottom of the main span section (10) and the top of the side span pier (2), respectively. A second support (5) is supported above the first support (4), and the first support (4) slides with the second support (5) through a sliding pair; a side span template (7) is installed and fixed on the second support (5); the side span template (7) is used for casting the side span section; The connecting mechanism is installed at the bottom of the main span (10) and is connected to the end of the second support (5) near the main span (10).

2. The bridge side span cast-in-place formwork system without post-cast strips according to claim 1, characterized in that: The sliding pair includes a plurality of supporting steel bars (61), which are laid on the top of the first support (4) along the length direction of the first support (4), and the bottom of the second support (5) abuts against the plurality of supporting steel bars (61).

3. A bridge side span cast-in-place formwork system without post-cast strips according to claim 2, characterized in that: The top of the first support (4) is provided with a limiting frame (6) corresponding to a plurality of the supporting steel bars (61), and the plurality of supporting steel bars (61) are all located within the limiting frame (6), with the outer periphery of the top of the supporting steel bars (61) protruding from the upper surface of the limiting frame (6).

4. The bridge side span cast-in-place formwork system without post-cast strips according to claim 1, characterized in that: The sliding pair includes a PTFE plate (62); the PTFE plate (62) is laid on the top of the first support (4) along the length direction of the first support (4); the bottom of the second support (5) is disposed against the PTFE plate (62).

5. A bridge side span cast-in-place formwork system without post-cast strips according to claim 1, characterized in that: The connecting mechanism includes several connecting seats (8) pre-embedded at the bottom of the main span (10). A through-hole jack (81) is installed on the connecting seat (8). Each through-hole jack (81) is tensioned with a steel strand (82). Each steel strand (82) is connected to one end of the second support (5) near the main span (10).

6. A bridge side span cast-in-place formwork system without post-cast strips according to claim 1, characterized in that: The first support (4) is vertically supported on both sides by a plurality of limiting rods (41), and the second support (5) is located between the plurality of limiting rods (41) on both sides of the first support (4).

7. A bridge side span cast-in-place formwork system without post-cast strips according to claim 6, characterized in that: Each of the limiting rods (41) is supported by a limiting jack (42) at its top, and the limiting jack (42) is positioned facing the second support (5).

8. A construction method for a bridge side span cast-in-place formwork system without post-cast strips as described in any one of claims 1 to 7, characterized in that: Includes the following steps: S1: Temporary support (3) erection: Temporary support (3) is erected between the main span pier (1) and the side span pier (2); S2: First support (4) erection: The first support (4) is installed and fixed on the top of the temporary support (3); S3: Sliding pair installation: Install the sliding pair on the top of the first support (4): S4: Second support (5) installation: The second support (5) is installed and fixed on the top of the sliding pair; S5: Installation of connecting mechanism: Install the connecting mechanism at the bottom of the main span (10) and connect the connecting mechanism to the end of the second support (5) near the main span (10); S6: Side span formwork (7) installation: Install and fix the side span formwork (7) for pouring the side span section on the second support (5).

Images