Fish-bellied cast-in-place box girder inner and outer mold supporting system structure and construction method

Abstract

The fish-bellied cast-in-place box girder inner and outer mold supporting system structure comprises supports, brackets, distribution wood joists, bottom molds and inner molds, the supports comprise transverse supports and longitudinal supports, the longitudinal supports are evenly distributed, the transverse supports are connected with all the longitudinal supports, the bottoms of the longitudinal supports are located on a concrete hardened layer, and the inner molds are arranged on the brackets. The bottom of the bracket is installed on the top of the longitudinal support, a plurality of distribution wood joists are longitudinally placed on the bracket, the bottom die is laid on the distribution wood joists, and the inner die is installed on the bottom die. The bracket is arranged to adapt to the linear change of the fish-bellied cast-in-place box girder, the movable inner formwork supporting system is used for ensuring the overall concrete pouring quality of the bottom web of the box girder, stress is reasonable, formwork mounting and dismounting construction is convenient, and the safety and quality of the cast-in-place box girder are guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of bridge construction, and more particularly to a fish-belly cast-in-situ box girder inner and outer formwork support system structure and a construction method. Background Art

[0002] With the continuous development of urban construction, in order to solve the increasingly tense traffic situation, municipal transportation continues to extend into three-dimensional space, and municipal bridges play a core hub function in it. In order to solve the shortcomings of cast-in-place box girders in municipal bridges, such as being heavy, consumable, and having unsightly lines, fish-belly cast-in-place box girders have become a landscape in urban construction with their light weight, material saving and environmental protection, smooth lines, and beautiful appearance. Compared with linear cast-in-place box girders, the construction technology has its own uniqueness, so the internal and external formwork support system structure of fish-belly cast-in-place box girders is particularly important.

[0003] Currently, there are patents for related fish-belly cast-in-situ box girder inner and outer formwork support system structures. For example, the utility model patent with application number CN201821599649.X discloses a method for a fish-belly concrete box girder cast-in-situ construction formwork support frame. The bridge pier caps at both ends of the fish-belly concrete box girder serve as end seats, on which steel pipe support end columns are supported. The middle concrete strip foundation in the middle of the span serves as the middle seat, on which a steel pipe support middle column is supported. Sand boxes are respectively provided on the top of the steel pipe support end columns and the steel pipe support middle column. A transverse load-bearing beam is provided on the top of the sand boxes. Multiple groups of Bailey beams are provided on the top of the transverse load-bearing beams along the bridge direction. Each group of Bailey beams forms a formwork support frame, and the fixed composite steel formwork is supported on the top of the Bailey beams. The existing technology includes the fish-belly cast-in-place box girder inner and outer formwork support system structure disclosed in the above patents, which is usually complicated and consumes a lot of steel. The installation support effect of the inner formwork is poor, the two ends are prone to shaking, the operating efficiency is low and the quality is difficult to guarantee. Summary of the Invention

[0004] In response to the above-mentioned problems existing in the prior art, the present invention provides a fish-belly cast-in-situ box girder inner and outer formwork support system structure and construction method, which makes the formwork installation and disassembly construction convenient, the cast-in-situ box girder safe and the inner formwork installation stable.

[0005] The present invention adopts the following technical solutions:

[0006] A fish-belly cast-in-situ box girder inner and outer formwork support system structure includes a bracket, a support, a distribution rib, a bottom formwork and an inner formwork. The bracket includes a transverse bracket and a longitudinal bracket. The longitudinal brackets are evenly distributed. The transverse bracket connects all the longitudinal brackets. The bottom of the longitudinal bracket is located on the concrete hardening layer. The bottom of the bracket is installed on the top of the longitudinal bracket. Multiple distribution ribs are placed longitudinally on the bracket. The bottom formwork is laid on the distribution ribs. The inner formwork is installed on the bottom formwork.

[0007] In one embodiment of the present invention, a hardened concrete layer is provided on the foundation. Both sides of the hardened concrete layer are 1.25m wider than the projected width of the box beam. As a load-bearing structural layer, a plurality of buffer wooden boards are provided on the hardened concrete layer, and the bottom of the longitudinal bracket is located on the buffer wooden boards.

[0008] In one embodiment of the present invention, a 0.5% one-way drainage slope is set on the concrete hardened layer, the drainage direction is away from the side of the walkway, and a drainage ditch is set on the side away from the walkway.

[0009] In one embodiment of the present invention, the bracket is a symmetrical structure, and the bracket includes a supporting stinger frame and an arc-shaped steel pipe. The supporting stinger frame includes an inclined support pipe, a plurality of vertical stingers and a vertical support pipe located on the outside. The inclined support pipe is installed between the vertical support pipes and the vertical stingers, and the arc-shaped steel pipe is installed on the top of the inclined support pipe and the vertical stinger.

[0010] In one embodiment of the present invention, triangular support frames are installed on the vertical support tube and the outermost inclined support tube, and both sides of the upper end of the inner mold are located between the triangular support frames.

[0011] In one embodiment of the present invention, the vertical support tube and the vertical tube support are both connected to the longitudinal bracket.

[0012] In one embodiment of the present invention, the split timber is square timber, and the bottom formwork is bamboo plywood.

[0013] The present invention also discloses a method for constructing a fish-belly cast-in-situ box beam inner and outer formwork support system structure, comprising the following steps:

[0014] Step S1, foundation treatment: In the fill area, the surface is cleaned within the foundation treatment range using an excavator, with the surface clearing depth being no less than 15 cm; the excavation area needs to be excavated to meet the requirement of at least 40 cm thickness of lime soil in Zone 96, and the foundation pit is backfilled with medium-coarse sand or clay in layers with a thickness of 50 cm and a compaction degree of no less than 95%. A 16-ton smooth-wheel roller is used to backfill the foundation pit, and the treated surface is compacted using the 16-ton smooth-wheel roller with a compaction degree of no less than 95%;

[0015] Step S2: A 15cm thick C20 concrete hardened layer is poured. The surface layer is set with a 0.5% one-way drainage slope. The drainage direction is away from the sidewalk. A drainage ditch is set on the side away from the sidewalk. The ditch is 0.6m wide at the top and 0.4m wide at the bottom, and 0.25m deep. The surface is protected with a 5cm thick C20 plain concrete plaster. The ditch is connected to the local drainage or ditch.

[0016] Step S3: Setting up the support. An adjustable top support is set on the top of the support. The extension length of the top support shall not exceed 30 cm. A longitudinal support wood with a thickness of 10 cm is set on the adjustable top support. A cross-section scissors brace is set every 6 to 7 m of the overall support. The angle between the scissors brace diagonal rod and the ground should be 45° to 60°.

[0017] Step S4, setting up the bracket;

[0018] Step S5: Install the distribution ribs, and lay 5*8cm square timbers on the bracket as formwork ribs, with the spacing between the timbers being 20cm at the web and 25cm at other locations;

[0019] Step S6: Laying the bottom formwork: Laying the bottom formwork on the distribution slats uses 12mm thick bamboo plywood, with a single section plane size of 1.22m×2.44m. Use the straight bending method to place the bamboo plywood along the arc formed by the bracket and nail it with iron nails and square wood. The long side of the formwork is laid in the horizontal direction, and the gaps between the boards are filled with double-sided tape;

[0020] Step S7: Install the inner formwork, using 15mm bamboo plywood as the panel and 5*8cm ribs, with the rib spacing no greater than 30cm. After the bottom plate and web reinforcement are completed, the inner formwork is installed. Since the box girder adopts a secondary casting process, when the inner formwork is erected for the first time, the inner formwork is manufactured in blocks according to the structural dimensions and assembled on the bridge to complete the installation. When the inner formwork is erected for the second time, the inner formwork is manufactured in blocks as a whole and directly hoisted and assembled to complete the installation.

[0021] Beneficial effects:

[0022] The present invention adds a bracket, the bottom form is installed on the bracket, and the inner form is movably installed at the bottom form. The inner form does not need to be directly installed on the bracket. It can adapt to the linear changes of the fish-belly cast-in-place box girder and ensure the overall quality of the concrete pouring of the bottom web of the box girder. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention and its features, aspects and advantages will become more apparent from reading the detailed description of the embodiments with reference to the following drawings, which illustrate the subject matter of the invention.

[0024] Figure 1 Schematic diagram of an embodiment of the present invention;

[0025] Figure 2 A partial schematic diagram of an embodiment of the present invention;

[0026] Figure 3 This is another partial schematic diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] As shown in the figure, the present invention discloses a fish-belly cast-in-place box girder inner and outer mold support system structure, including a bracket 1, a bracket 2, a distribution rib 3, a bottom mold 4 and an inner mold 5. The bracket 1 includes a transverse bracket 101 and a longitudinal bracket 102. The longitudinal brackets 102 are evenly distributed. The transverse bracket 101 connects all the longitudinal brackets 102. The bottom of the longitudinal bracket 102 is located on the concrete hardening layer 6. The bottom of the bracket 2 is installed on the top of the longitudinal bracket 102. Multiple distribution ribs 3 are placed longitudinally on the bracket 2. The bottom mold 4 is laid on the distribution rib 3. The inner mold 5 is installed on the bottom mold 4. The inner mold 5 is movably installed on the bottom mold 4 for easy installation and replacement.

[0029] The present invention designs a bracket 2 for installing the bottom formwork 4. Compared with the traditional inner and outer formwork support system, the present invention adds a bracket, and the inner formwork 5 does not need to be directly installed on the longitudinal bracket 102 of the bracket 1. It can adapt to the linear changes of the fish-belly cast-in-place box girder while ensuring the overall quality of the concrete pouring of the bottom web of the box girder.

[0030] Of course, in order to increase the strength of the bracket 1, scissor support diagonal rods 103 are installed at the transverse bracket 101 and the longitudinal bracket 102.

[0031] In one embodiment of the present invention, a hardened concrete layer 6 is disposed on a foundation 7. The two sides of the hardened concrete layer 6 are 1.25 m wider than the projected width of the box girder. The hardened concrete layer 6 serves as a load-bearing structural layer. Several buffer wood panels 8 are positioned on the hardened concrete layer 6, and the bottoms of the longitudinal supports 102 are located on the buffer wood panels 8. Before installation, the buffer wood panels 8 must be leveled with mortar or fine sand to ensure uniform load distribution.

[0032] The concrete hardened layer 6 is at least 20 cm above the ground.

[0033] In one embodiment of the present invention, the concrete hardened layer 6 is provided with a 0.5% one-way drainage slope, the drainage direction is away from the side of the walkway, and a drainage ditch 9 is provided on the side away from the walkway.

[0034] In one embodiment of the present invention, the bracket 2 is a symmetrical structure. The bracket 2 includes a supporting stinger frame 21 and an arc-shaped steel pipe. The supporting stinger frame includes an inclined support pipe 22, a plurality of vertical stingers 23 and a vertical support pipe 24 located on the outside. The inclined support pipe 22 is installed between the vertical support pipes 23 and the vertical stingers 23, and the arc-shaped steel pipe 21 is installed on the top of the inclined support pipe 22 and the vertical stinger 23.

[0035] In one embodiment of the present invention, triangular support frames 25 are installed on the vertical support tube 24 and the outermost inclined support tube 22 , and both sides of the upper end of the inner mold 5 are located between the triangular support frames 25 .

[0036] In one embodiment of the present invention, the vertical support tube 24 and the vertical tube support 23 are both connected to the longitudinal bracket 102 .

[0037] In one embodiment of the present invention, the partition wood 3 is square wood, and the bottom mold 4 is bamboo plywood.

[0038] The present invention also discloses a method for constructing a fish-belly cast-in-situ box beam inner and outer formwork support system structure, comprising the following steps:

[0039] Step S1, foundation treatment: In the filling area, use an excavator to clean the humus, silt, and other unfavorable soil on the surface within the foundation treatment range, with a surface clearing depth of no less than 15 cm; the excavation area must be excavated to meet the requirement of at least 40 cm thickness of lime soil in Zone 96. The foundation pit is backfilled with medium-coarse sand or clay in layers, with a layer thickness of about 50 cm and a compaction degree of no less than 95%. In principle, a 16-ton smooth-wheel roller is used for backfilling. In some places where the roller cannot operate, a vibratory rammer is used for compaction. The treated surface is compacted with a 16-ton smooth-wheel roller, with a compaction degree of no less than 95%;

[0040] Step S2: A 15cm thick C20 concrete hardened layer is poured. The surface layer is set with a 0.5% one-way drainage slope. The drainage direction is away from the sidewalk. A drainage ditch is set on the side away from the sidewalk. The ditch is 0.6m wide at the top and 0.4m wide at the bottom, and 0.25m deep. The surface is protected with a 5cm thick C20 plain concrete plaster. The ditch is connected to the local drainage or ditch.

[0041] Step S3: Scaffolding is erected. The scaffolding is constructed using a φ48 bowl-shaped or disc-shaped scaffolding. Adjustable supports are installed on the top of the scaffolding. The extension of the supports should not exceed 30 cm to ensure the stability of the free end of the scaffolding. 10 cm thick longitudinal support wood is installed on the adjustable supports. A cross-sectional scissor brace is installed every 6 to 7 meters of the entire scaffolding. The angle between the diagonal rod of the scissor brace and the ground should be 45° to 60°.

[0042] Step S4, setting up the bracket;

[0043] Step S5: Install the distribution ribs, and lay 5*8cm square timbers on the bracket as formwork ribs, with the spacing between the timbers being 20cm at the web and 25cm at other locations;

[0044] Step S6: Laying the bottom formwork: Laying the bottom formwork on the distribution ribs, using 12mm thick bamboo plywood with a single section plane size of 1.22m×2.44m. Using the straight bending method, the bamboo plywood is placed along the arc formed by the bracket and nailed with iron nails and square wood. To reduce longitudinal joints and improve the appearance of the box beam after demolding, the long side of the formwork is laid in the horizontal direction, and the gaps between the boards are filled with double-sided tape.

[0045] Step S7: Install the inner formwork, primarily constructed from 15mm bamboo plywood panels and 5x8cm ribs, with spacing no greater than 30cm between the ribs. The inner formwork is installed after the base plate and web reinforcement are complete. Because the box girder utilizes a secondary casting process, the first erection of the inner formwork is performed by manufacturing the formwork in sections based on the structural dimensions and assembling it on the bridge. The second erection of the inner formwork is performed by directly hoisting and assembling the sections (including chamfers). A 1.0x1.5m window is reserved at the quarter-point of each hole in the top plate of the box girder to allow for future removal of the inner formwork and other components. The overlap of the top plate reinforcement at the window is performed in accordance with regulatory requirements. The inner formwork is primarily reinforced using tensioning. To prevent the inner formwork from floating during the first pour, tie rods are installed, one end of which is secured to the base formwork.

[0046] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-mentioned disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention that do not depart from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A fish-belly cast-in-situ box girder inner and outer formwork support system structure, characterized in that: It includes a bracket, a support, a distribution rib, a bottom mold and an inner mold. The bracket includes a horizontal bracket and a vertical bracket. The vertical brackets are evenly distributed. The horizontal bracket connects all the vertical brackets. The bottom of the vertical bracket is located on the concrete hardening layer. The bottom of the bracket is installed on the top of the longitudinal bracket. Multiple distribution ribs are placed vertically on the bracket. The bottom mold is laid on the distribution ribs, and the inner mold is installed on the bottom mold.

2. The fish-belly cast-in-situ box beam inner and outer formwork support system according to claim 1, characterized in that: The concrete hardening layer is set on the foundation. The two sides of the concrete hardening layer are 1.25m wider than the projection width of the box beam. As the load-bearing structural layer, several buffer wooden boards are set on the concrete hardening layer, and the bottom of the longitudinal bracket is located on the buffer wooden boards.

3. The fish-belly cast-in-situ box beam inner and outer formwork support system according to claim 2, characterized in that: The concrete hardened layer is set with a one-way drainage slope of 0.5%, and the drainage direction is away from the side of the footpath. A drainage ditch is set on the side away from the footpath.

4. The fish-belly cast-in-situ box girder inner and outer formwork support system according to claim 1, characterized in that: The bracket is a symmetrical structure. The bracket includes a supporting stinger frame and an arc-shaped steel pipe. The supporting stinger frame includes an inclined supporting pipe, several vertical stingers and a vertical supporting pipe located on the outside. The inclined supporting pipe is installed between the vertical supporting pipes and the vertical stingers, and the arc-shaped steel pipe is installed on the top of the inclined supporting pipe and the vertical stinger.

5. The fish-belly cast-in-situ box girder inner and outer formwork support system according to claim 4, characterized in that: Triangular support frames are installed on the vertical support tube and the outermost inclined support tube, and both sides of the upper end of the inner mold are located between the triangular support frames.

6. The fish-belly cast-in-situ box beam inner and outer formwork support system according to claim 4, characterized in that: The vertical support tube and the vertical tube support are both connected to the longitudinal support.

7. The fish-belly cast-in-situ box girder inner and outer formwork support system according to claim 1, characterized in that: The distribution of the slats is square wood, the bottom formwork is bamboo plywood.

8. A construction method for a fish-belly cast-in-situ box girder inner and outer formwork support system, characterized in that: The following steps are involved: Step S1, foundation treatment: In the fill area, the surface is cleaned within the foundation treatment range using an excavator, with the surface clearing depth being no less than 15 cm; the excavation area needs to be excavated to meet the requirement of at least 40 cm thickness of lime soil in Zone 96, and the foundation pit is backfilled with medium-coarse sand or clay in layers with a thickness of 50 cm and a compaction degree of no less than 95%. A 16-ton smooth-wheel roller is used to backfill the foundation pit, and the treated surface is compacted using the 16-ton smooth-wheel roller with a compaction degree of no less than 95%; Step S2: A 15cm thick C20 concrete hardened layer is poured. The surface layer is set with a 0.5% one-way drainage slope. The drainage direction is away from the sidewalk. A drainage ditch is set on the side away from the sidewalk. The ditch is 0.6m wide at the top and 0.4m wide at the bottom, and 0.25m deep. The surface is protected with a 5cm thick C20 plain concrete plaster. The ditch is connected to the local drainage or ditch. Step S3: Setting up the support. An adjustable top support is set on the top of the support. The extension length of the top support shall not exceed 30 cm. A longitudinal support wood with a thickness of 10 cm is set on the adjustable top support. A cross-section scissors brace is set every 6 to 7 m of the overall support. The angle between the scissors brace diagonal rod and the ground should be 45° to 60°. Step S4, setting up the bracket; Step S5: Install the distribution ribs, and lay 5*8cm square timbers on the bracket as formwork ribs, with the spacing between the timbers being 20cm at the web and 25cm at other locations; Step S6: Laying the bottom formwork: Laying the bottom formwork on the distribution slats uses 12mm thick bamboo plywood, with a single section plane size of 1.22m×2.44m. Use the straight bending method to place the bamboo plywood along the arc formed by the bracket and nail it with iron nails and square wood. The long side of the formwork is laid in the horizontal direction, and the gaps between the boards are filled with double-sided tape; Step S7: Install the inner formwork, using 15mm bamboo plywood as the panel and 5*8cm ribs. The rib spacing is no more than 30cm. After the bottom plate and web reinforcement are completed, the inner formwork is installed. The box girder adopts a secondary casting process. When the inner formwork is erected for the first time, the inner formwork is manufactured in blocks according to the structural dimensions and assembled on the bridge to complete the installation. When the inner formwork is erected for the second time, the inner formwork is manufactured in blocks as a whole and directly hoisted and assembled to complete the installation of the inner formwork.

Images