Construction technology of capping beam door opening formwork

Abstract

The invention relates to a construction technology of a capping beam door opening formwork. The construction technology comprises the following steps that S1, surveying and setting out are conducted, specifically, a surveying worker uses a total station to conduct unified surveying and setting on the erecting range and the height stroke of the formwork; s2, foundation treatment, wherein a fertilizer groove of the bearing platform is backfilled with plain soil in a layered mode; s3, a concrete foundation is poured, specifically, the size of the concrete foundation is determined by a measurer, and then concrete is poured; s4, mounting a steel pipe column: connecting the steel pipe column with a bolt prefabricated on the foundation through a bottom flange plate; s5, double-spliced 40a I-shaped steel and bailey beams are installed, specifically, the 40a I-shaped steel is installed at the top ends of the steel pipe columns, and then two rows of bailey beams are installed on the 40a I-shaped steel; s6, double-spliced 25a I-shaped steel is installed, specifically, the placing position of the 25a I-shaped steel is marked above the bailey beam, and the 25a I-shaped steel is installed on the bailey beam; s7, square timbers and formworks are installed, specifically, a plurality of square timbers are installed on the 25a I-shaped steel; and S8, concrete pouring is conducted, specifically, three layers of concrete are horizontally poured on the square timber. The method has the effect of improving the applicability of the bailey beam structure.

Description

Technical Field

[0001] The invention relates to the technical field of cap beam construction, and in particular to a cap beam door opening formwork construction process. Background Art

[0002] With the rapid development of cities, more and more viaducts are being built, and many cross-line bridges have inevitably appeared. Building bridges on existing roads will inevitably affect the traffic on the roads below. In order to ensure the basic passage of traffic during the construction of viaducts, setting up doorway brackets has become an effective way to solve this problem.

[0003] Bailey beams have the characteristics of simple structure, convenient transportation, quick erection, large bearing capacity, good interchangeability, strong adaptability, etc. They can perfectly meet the requirements of short construction period and fast pace, and also meet the requirements of safety and strong bearing capacity, and are gradually being widely used in the construction of bridge projects.

[0004] The usual Bailey beam structure is: four steel pipe columns are erected under the Bailey beam, the Bailey beam is erected on the steel pipe columns, and then a distribution beam and a buckle frame are set up above the Bailey beam, so that the distribution beam fits the bottom of the cap beam, and the distance between the cap beam and the ground is the clearance area (i.e. the effective driving height).

[0005] Although the above design can effectively support the cap beam, the Bailey beam will occupy part of the clearance area, so it is only suitable for situations where the clearance area is sufficient. If the clearance area is relatively compact and the specified driving height must be met, the above Bailey beam structure is no longer applicable because the Bailey beam may hinder the passage of vehicles, reducing the applicability of the Bailey beam structure. Summary of the invention

[0006] In order to solve the problem of insufficient clearance below the cap beam structure when the distribution beam is erected above the main beam, and to ensure traffic safety and construction safety, the present application provides a cap beam door opening formwork construction process.

[0007] This application provides a cap beam door opening formwork construction process using the following technical solutions: A construction process for a cap beam door opening formwork, comprising the following steps: S1, measuring and setting out: the site is leveled in advance before setting out, and a surveyor uses a total station to uniformly measure and set the formwork erection range and height travel, and then rechecks the measured dimensions after measuring and setting; S2, foundation treatment: the cap is set under the foundation, the fertilizer trough of the cap is backfilled with raw soil in layers, and the raw soil is compacted, the surface impurities are removed, and pre-filling rolling is performed. The foundation treatment range requires that each side must be more than 50 cm wider than the formwork structure. After the treatment is completed, the surface is 15-20 cm higher than the surrounding surface, and a 1% cross slope is left on the surface, and drainage ditches are set on both sides of the foundation; S3, pouring concrete foundation: the surveyor determines the length, width and height of the concrete foundation, sets the position of the concrete foundation, and measures the elevation of the concrete top surface; S4, installing steel pipe columns: after the steel pipe columns are hoisted, the steel pipe columns are connected to the prefabricated bolts on the foundation through the bottom flange; S5, installing double-piece 40a I-beam Steel and Bailey beam: hoist the 40a I-beam and install it on the top of several steel pipe columns, then install two rows of Bailey beams on the 40a I-beam. The Bailey beam requires a span of 12.3m and a spacing of 0.45m. S6. Install double 25a I-beams: mark the placement position of each group of 25a I-beams above the Bailey beam, then transport the 25a I-beams to the bottom of the cap beam, use a lift to hoist the 25a I-beams on one side of the Bailey beam, and install the 25a I-beams. Installed on Bailey beams, the double-jointed 25a I-beams have a span of 5.5m and a spacing of 0.5m. The cap beam is set on the 25a I-beam and is located between two rows of Bailey beams; S7, installation of square timber and formwork: install several square timbers with a length and width of 8cm on the 25a I-beam. The square timber is required to have a span of 0.5m and a spacing of 0.16m; S8, concrete pouring: concrete is poured horizontally on the square timber in three layers, from both ends to the middle, and the pouring thickness of each layer is 30cm.

[0008] By adopting the above technical solution, during construction, the construction workers first measure and lay out the site, then dig a fertilizer trough underground, set a cap in the fertilizer trough, backfill the fertilizer trough and compact it, then pour a concrete foundation on the surface, then hoist the steel pipe column, and install the steel pipe column on the concrete foundation, install 40a I-beams and Bailey beams on the steel pipe column in sequence, then install double-piece 25a I-beams on the Bailey beam, then lay square timber on the 25a I-beam, and finally pour concrete on the square timber, thus realizing the construction process of the cap beam door opening formwork. The construction workers install the 25a I-beam at the bottom of the Bailey beam and place the cap beam on the 25a I-beam. Compared with the existing technology, the Bailey beam and the cap beam overlap in the height direction, so that the phenomenon of the Bailey beam occupying the clearance area can be avoided, the clearance area is expanded as much as possible, the normal passage of vehicles is guaranteed, and the applicability of the Bailey beam structure is improved.

[0009] Optionally, in the step S2, after the foundation treatment is completed, a 40 cm thick graded gravel foundation is made, the graded gravel is filled in two layers, and the graded gravel is heavily compacted, with a compaction degree of not less than 96%.

[0010] By adopting the above technical solution, only backfilling the cap fertilizer trough with backfill soil cannot meet the stability standard of the foundation. By laying graded gravel and subsequent concrete foundation, the strength and stability of the entire foundation can be improved to meet the stability standard of the foundation.

[0011] Optionally, in step S4, before hoisting the steel pipe column, first check whether the elevation of the concrete top surface is consistent with the plan, then hoist the steel pipe column, preliminarily reinforce the steel pipe column, adjust the verticality of the steel pipe column to meet the requirements, and then perform final reinforcement, and finally check the verticality and elevation of the steel pipe column.

[0012] By adopting the above technical solution, the steel pipe column is initially reinforced with semi-locking bolts and finally reinforced with locking bolts. Checking the verticality and elevation of the steel pipe column when tightening it can improve the accuracy of the steel pipe column installation, so that the Bailey beam can be installed better and more accurately, and the structural strength of the overall Bailey beam structure can be improved.

[0013] Optionally, in step S6, when hoisting the I-beam 25a, the lifting point of the crane is arranged between the two groups of Bailey beams, and two lifting points are set on the I-beam 25a, which are located at the center position in the length direction of the I-beam 25a and 2m away from the end direction.

[0014] By adopting the above technical solution, the lifting point of the crane is arranged between the two groups of Bailey beams and the lifting point of the 25a I-beam is set, which is mainly used to horizontally lift the 25a I-beam, ensure the stability of the 25a I-beam when lifting, is conducive to the installation of the 25a I-beam, and can reduce the possibility of construction accidents.

[0015] Optionally, in step S6, before hoisting the 25a I-beam, short-section steel bars are used to connect the ends of two 25a I-beams.

[0016] By adopting the above technical solution, the 25a I-beam is longer and heavier, so when installing the 25a I-beam, it is difficult to adjust the position of the 25a I-beam, which increases the construction difficulty of the construction workers. The construction workers use short-circuit steel bars to connect the two ends of the 25a I-beams to preliminarily define the relative position and distance between the two 25a I-beams, which provides convenient conditions for the subsequent installation of the 25a I-beams. Only the short-circuit steel bars need to be removed later.

[0017] Optionally, in step S8, the slump and workability of the concrete are tested before pouring, and the slump is required to be 180±20 mm.

[0018] By adopting the above technical solution, in order to provide a stable structure, it is necessary to first ensure the load performance of the concrete after solidification. Therefore, the index parameters of the concrete need to be tested before pouring the concrete. If the concrete parameters do not meet the specified standard range, there is a possibility of cracking due to load after the concrete solidifies. Slump and workability are performance indicators of concrete, and both indicators meet the requirements.

[0019] Optionally, during pouring, the pouring speed of concrete is controlled at 0.5-1.0 m / h, and the free fall height of concrete is ensured to be no greater than 2 m.

[0020] By adopting the above technical solution and limiting the pouring speed and pouring height of concrete, the impact on the lower concrete layer after vibration can be reduced as much as possible, further reducing the possibility of segregation of the lower concrete.

[0021] Optionally, after pouring the concrete, the concrete is vibrated until the concrete stops sinking, bubbles no longer appear, the surface is flat, and the slurry is present.

[0022] By adopting the above technical solution, there is a possibility of air inside the concrete when pouring, resulting in a cavity inside the concrete after solidification, which will affect its load performance due to insufficient density of the concrete. Vibrate the inside of the concrete to fill the internal space of the concrete to ensure the density of the concrete, thereby ensuring the load performance of the concrete after solidification.

[0023] Optionally, after vibrating the concrete, at room temperature, after the cap beam concrete surface is set and solidified, cover it with non-woven fabric and sprinkle water for curing. After 24 hours, loosen the support of the side formwork to leave a gap between the formwork and the concrete surface. The concrete should be cured in the formwork for no less than three days.

[0024] By adopting the above technical solution, the main purpose of concrete curing is to create suitable temperature and humidity conditions to promote the hydration of concrete, thereby ensuring the strength and stability of concrete and preventing cracks on the concrete surface due to rapid evaporation of water.

[0025] Optionally, after performing the step S8, the frame is dismantled. The dismantling is carried out according to the principle of installing first and dismantling later, or installing later and dismantling first. Start from the top layer and dismantle downwards layer by layer. The upper and lower layers shall not be operated simultaneously.

[0026] By adopting the above technical solution, since the frame is large in size and weight, a crane is needed for dismantling, so it is more appropriate to start from the top floor, and dismantling it layer by layer is beneficial to construction safety.

[0027] In summary, the present application includes at least one of the following beneficial technical effects: 1. During construction, the construction workers first measured and laid out the site, then dug a fertilizer trough underground, set up a cap in the fertilizer trough, backfilled the fertilizer trough and compacted it, then poured a concrete foundation on the surface, then hoisted the steel pipe column, and installed the steel pipe column on the concrete foundation, and installed 40a I-beams and Bailey beams on the steel pipe columns in sequence, and then installed double-piece 25a I-beams on the Bailey beams, and then laid square timbers on the 25a I-beams, and finally poured concrete on the square timbers, realizing the construction process of the cap beam door opening formwork. The construction workers installed the 25a I-beam at the bottom of the Bailey beam and placed the cap beam on the 25a I-beam. Compared with the existing technology, the Bailey beam and the cap beam overlap in the height direction, so that the phenomenon of the Bailey beam occupying the clearance area can be avoided, the clearance area can be expanded as much as possible, the normal passage of vehicles is guaranteed, and the applicability of the Bailey beam structure is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a construction process diagram of the formwork in the embodiment of the present application.

[0029] Figure 2 It is a schematic diagram of the structure of 25a and Bailey beam in the embodiment of the present application.

[0030] Figure 3 It is an exploded diagram used to illustrate the structure of the positioning component in the embodiment of the present application.

[0031] Figure 4 It is an exploded view used to illustrate the structure of the locking assembly in the embodiment of the present application.

[0032] Figure 5 It is a cross-sectional view used to illustrate the structure of the locking assembly in the embodiment of the present application.

[0033] Explanation of the reference numerals: 1. Bailey beam; 2. 25a I-beam; 3. Positioning assembly; 31. Guide plate; 32. Positioning column; 4. Locking assembly; 41. Connecting screw; 42. Fixed block; 43. Sliding block; 44. Locking block; 441. Pressing protrusion; 45. Lifting plate; 46. Anti-loosening plate; 5. Locking handwheel; 51. Connecting column. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1-Figure 5 This application is described in further detail.

[0035] The present application embodiment discloses a cap beam door opening formwork construction process. Figure 1 The construction process of the cap beam door formwork includes the following steps: S1. Surveying and laying out: The site should be leveled before laying out. The surveying personnel will use a total station to uniformly measure the formwork erection range and height travel. After the surveying and setting, they will review to avoid measurement errors.

[0036] Measurement and layout are used to plan the erection position and size of the entire frame. It is an important preparatory work before formwork construction to ensure that subsequent construction can proceed smoothly without affecting other areas.

[0037] S2. Foundation treatment: dig a fertilizer trough on the foundation, set a pedestal in the fertilizer trough, then backfill the fertilizer trough with plain soil in layers and compact it, with a compaction degree of not less than 93%; the scope of foundation treatment requires that each side must be at least 50cm wider than the frame structure. After the treatment, the surface is 15-20cm higher than the ground surface, and a 1% horizontal slope is left on the surface. Drainage ditches are set on both sides of the formwork foundation; after the foundation treatment, make a 40cm graded gravel foundation. The graded gravel is filled in two layers, and the graded gravel is heavily compacted, with a compaction degree of not less than 96%.

[0038] The pedestal is used as the foundation for the subsequent installation of steel pipe columns and is also the supporting foundation for the entire formwork. The fertilizer trough is used to stabilize the pedestal, reducing the possibility of displacement of the pedestal due to load.

[0039] S3. Casting concrete foundation: The surveying personnel shall determine the length, width and height of the concrete foundation, set the position of the concrete foundation, and measure the elevation of the top surface of the concrete.

[0040] S4. Install the steel pipe column: first check whether the elevation of the top surface of the concrete foundation is consistent with the plan, and then hoist the steel pipe column. The steel pipe column is connected to the prefabricated bolts on the foundation through the bottom flange. During installation, half-tighten the bolts first to preliminarily reinforce the steel pipe column, adjust the verticality of the steel pipe column and then fully tighten the bolts to finally reinforce the steel pipe column. At this time, check the verticality and elevation of the steel pipe column.

[0041] In order to improve the assembly accuracy and load performance of the formwork and ensure that the verticality of the steel pipe column directly affects the installation accuracy of the subsequent Bailey beam 1, it is necessary to check the verticality and elevation multiple times when installing the steel pipe column to ensure that the installation size meets the expected requirements.

[0042] S5. Install double 40a I-beams and Bailey beams 1: hoist the 40a I-beams and install them on the top of the steel pipe column. Then install a row of Bailey beams 1 on both sides of the 40a I-beams. The Bailey beams 1 are required to have a span of 12.3m and a spacing of 0.45m.

[0043] Bailey beam performance: (three-row single-layer reinforced type) Section modulus W = 23097400 mm3 Moment of inertia I = 1732303.2 cm4 Elastic modulus E = 2.06 × 105 MPa Allowable bending stress [σ] = 305 MPa Allowable shear stress [fV] = 175 MPa Strength verification: 86.57KN / m2, stiffness verification: 61.4KN / m2, span: 12.3m (1) Strength calculation: fmax=Mmax / W=1637×106÷23097400=70.87MPa<[σ]=205MPa (2) Shear force calculation Vmax=qb / 2=0.5×86.57×12.3=532.4KNfv=Vmax / hd=532.4×103 / (100×100)=53.2MPa<[fV]=175MPa (3) Stiffness verification =5×86.57×2.4×12.34 / 384×2.06×108×1732303.2×10-8 =0.017m=1.7cm<1230 / 400=3.075cmThe deflection meets the requirements.

[0044] S6. Install double 25a I-beams 2: Mark the placement of each group of 25a I-beams 2 above the Bailey beam 1, then transport the 25a I-beams 2 to the bottom of the cap beam, arrange the crane's lifting point between the two groups of Bailey beams 1, set two lifting points on the 25a I-beams 2, and locate them 2m from the middle to the end of the 25a I-beams 2, then connect the two 25a I-beams 2 with short-circuited steel bars, use a lifting vehicle to hoist the 25a I-beams 2 on one side of the Bailey beam 1, and install the 25a I-beams 2 on the Bailey beam 1, where the 25a I-beams 2 are required to have a span of 5.5m and a spacing of 0.5m. Use a crane to hoist the cap beam onto the 25a I-beams 2, and locate them between the two rows of Bailey beams 1.

[0045] I25a I-beam performance: Section modulus W = 401400mm3 Moment of inertia I = 5020cm4 Elastic modulus E = 2.06 × 105 MPa Allowable bending stress [σ] = 205 MPa Allowable shear stress [fV] = 115 MPa Weight 38.1 kg / m = 0.381 KN / m Strength calculation: 86.57KN / m2, stiffness calculation: 61.4KN / m2, span: 5.5m Strength verification (arrangement with spacing of 0.5m) fmax=Mmax / W=55.24×106÷401400 =137MPa<[σ]=205MPa The strength meets the requirements.

[0046] Shear force calculation (only considering the shear resistance of the I-beam web) Vmax=qb / 2=0.5×86.57×0.5×2.4×0.5=25.97KNfv=Vmax / hd=25.97×103 / (25×0.65×102)=15.98MPa<[fV]=115MPa Then the shear stress meets the requirements.

[0047] Stiffness calculation =0.0089m=0.89cm<510 / 400=1.275cm, the deflection meets the requirements.

[0048] Reference Figure 2 and Figure 3 A positioning assembly 3 is provided between the 25a I-beam 2 and the Bailey beam 1, and the positioning assembly 3 includes a guide plate 31 and a positioning column 32. The guide plates 31 are connected by bolts at the position of the 25a I-beam 2 corresponding to the Bailey beam 1. The guide plates 31 are provided with a guiding slope. The two guide plates 31 are arranged opposite to each other, and the distance between the two guide plates 31 gradually increases from the bottom end to the top end of the guide plate 31 as the reference direction. The positioning column 32 is fixedly connected to the 25a I-beam 2 and is located between the two guide plates 31.

[0049] Reference Figure 3 , Figure 4 and Figure 5 , a positioning hole is provided on the Bailey beam 1, the Bailey beam 1 is arranged between the two guide plates 31, and the positioning column 32 is plugged into the positioning hole. A locking assembly 4 is provided on the positioning column 32, and the locking assembly 4 includes a connecting screw 41, a fixed block 42, a sliding block 43, a locking block 44, a lifting plate 45 and an anti-loosening plate 46. A locking hole is provided on the positioning column 32, and the connecting screw 41 is vertically fixedly connected to the 25a I-beam 2 and is located in the locking hole. The fixed block 42 is fixedly connected to the connecting screw 41, and the lifting plate 45 is threadedly fitted on the connecting screw 41 and is located above the fixed block 42. The sliding block 43 is slidably fitted on the connecting screw 41 and is rotationally connected to the lifting plate 45.

[0050] Reference Figure 4 and Figure 5 A plurality of movable grooves are provided on the side wall of the positioning column 32. Two of them are used as an example in this embodiment. The locking block 44 is slidably fitted in the movable grooves. The locking block 44 is hinged between the sliding block 43 and the fixed block 42 through a connecting rod. A pressing protrusion 441 is provided on the locking block 44, and a groove is provided in the positioning hole at a position corresponding to the pressing protrusion 441.

[0051] Reference Figure 5 The anti-loosening plate 46 is threadedly engaged with the connecting screw 41 and is located above the lifting plate 45. The anti-loosening plate 46 is provided with a locking hand wheel 5, and the locking hand wheel 5 is connected with a plurality of connecting columns 51. The anti-loosening plate 46 has through holes at positions corresponding to the connecting columns 51, and the lifting plate 45 has countersunk holes at positions corresponding to the connecting columns 51.

[0052] During installation, the construction personnel fit the 25a I-beam 2 to the Bailey beam 1, so that the Bailey beam 1 is located between the two positioning plates, and the positioning column 32 is inserted into the positioning hole. Then the connecting column 51 is passed through the through hole and the countersunk hole in turn, and the locking hand wheel 5 is turned to make the lifting plate 45 and the anti-loosening plate 46 rotate synchronously, driving the sliding block 43 to descend, so that the locking hole moves until the pressing protrusion 441 is inserted into the groove, and then the locking hand wheel 5 is moved to make the connecting column 51 disengage from the countersunk hole, and then the anti-loosening plate 46 is turned to press against the lifting plate 45, so as to limit the degree of freedom of the 25a I-beam 2 and realize the installation of the 25a I-beam 2.

[0053] The construction workers used the positioning plate to limit the length direction position of the 25a I-beam 2, and cooperated with the positioning column 32 and the positioning hole to limit the width direction position of the 25a I-beam 2, and then used the locking assembly 4 to limit the positioning column 32 from falling out of the positioning hole, thereby achieving a stable installation of the 25a I-beam 2.

[0054] S7. Install square timber and formwork: Lay several square timbers with a square cross-section and a side dimension of 8 cm on 25a I-beam 2. The span of the square timber is required to be 0.5 m and the spacing is 0.16 m. Then lay a 1.5 cm formwork on the surface of the square timber, and then lay a 0.5 mm thick iron sheet on the formwork.

[0055] Square timber is used to pad the area near the cap beam, which helps with subsequent concrete pouring.

[0056] Square timber performance: Section modulus W = 85333 mm3 Moment of inertia I = 341 cm4 Elastic modulus E = 9000MPa Allowable bending stress [σ] = 13MPa Allowable shear stress [fV] = 1.4 MPa Strength verification: 86.57KN / m2, stiffness verification: 61.4KN / m2, span: 0.5m The calculation is based on a three-span continuous model, and the coefficients are: Km=-0.1, Kv=-0.6, Kf=0.677 Strength verification (arrangement with spacing of 0.16m) M max =K m ql 2=-0.1×86.57×0.16×0.52=-0.35KN·mfmax=Mmax / W=0.35×106÷85333 =4.1MPa<[σ]=13MPa The strength meets the requirements.

[0057] Shear force calculation V=Kvql=-0.6×86.57×0.16×0.5=4.15KN =0.97N / mm2<[fV]=1.4MPa Then the shear stress meets the requirements.

[0058] Stiffness calculation ωmax=Kfql4 / (100EI) =0.677×61.4×0.16×0.54 / (100×9000×103×341×10-8)=0.00014m=0.014cm<50 / 400=0.125cm, the deflection meets the requirements.

[0059] S8. Concrete pouring: Before pouring concrete, the slump and workability of concrete shall be tested and the slump shall be controlled at 180±20mm. Concrete shall be poured horizontally in three layers on the iron sheet. During pouring, concrete shall be poured from both ends to the middle so that the thickness of each layer of concrete is 30cm. The pouring speed of concrete shall be 0.5-1.0m / h, and the free fall height of concrete shall be ensured to be no more than 2m. After pouring one layer of concrete, the inside of the concrete shall be vibrated until the concrete no longer sinks, bubbles, and has a flat surface with slurry, and then the next layer shall be poured. After pouring, at room temperature, after the surface of the cap beam concrete is collected and solidified, it shall be covered with non-woven fabric and watered for curing. After 24 hours, the support of the side formwork shall be loosened to leave a gap between the formwork and the concrete surface. The concrete shall be cured with the formwork for no less than three days.

[0060] Controlling the pouring speed and pouring height of concrete can effectively prevent the segregation of the next layer of concrete. Concrete curing can effectively prevent cracks in concrete due to rapid evaporation of water, and can further improve the load-bearing performance of concrete.

[0061] After the construction of the cap beam is completed, the entire frame needs to be dismantled. The dismantling should be carried out according to the principle of installing first and then dismantling, or installing last and then dismantling. A crane should be used to start from the top floor of the frame and dismantle it downwards layer by layer. It is not allowed to operate simultaneously on the upper and lower floors.

[0062] The implementation principle of a cap beam door opening formwork construction process in an embodiment of the present application is as follows: during construction, the construction personnel first conduct measurements and layout to measure the erection range and height travel of the entire formwork, then dig a fertilizer trough to set up a cap, then pour a concrete foundation on the ground surface, use a crane to hoist the steel pipe column, and connect it to the foundation through a bottom flange, then install a 40a I-beam on the top of the steel pipe column, install Bailey beam 1 on the 40a I-beam, then install a 25a I-beam 2 on the bottom and top of the Bailey beam 1, then lay square timber on the 25a I-beam 2, and lay formwork and iron sheets on the surface of the square timber in turn, then pour three layers of concrete on the iron sheets, and maintain the concrete during solidification. After the construction of the cap beam and piers is completed, the entire formwork can be removed, and the formwork is removed from the top layer downwards, thus realizing the entire construction process of the formwork.

[0063] The construction workers installed the 25a I-beam 2 at the bottom end of the Bailey beam 1, and placed the cap beam on the 25a I-beam 2. Compared with the existing technology, the Bailey beam 1 and the cap beam overlapped in the height direction, which can avoid the phenomenon of the Bailey beam 1 occupying the clearance area, expand the clearance area as much as possible, ensure the normal passage of vehicles, and improve the applicability of the Bailey beam 1 structure.

[0064] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A cap beam door opening formwork construction process, characterized in that: The following steps are involved: S1. Surveying and setting out: The site should be leveled before setting out. The surveying personnel will use the total station to uniformly measure the formwork erection range and height travel. After the surveying and setting out, the measurement dimensions will be reviewed again. S2. Foundation treatment: The cap is set under the foundation. The fertilizer trough of the cap is backfilled with plain soil in layers, and the plain soil is compacted. The impurities on the surface are removed and rolled before filling. The scope of foundation treatment requires that each side must be more than 50cm wider than the formwork structure. After the treatment, the surface is 15-20cm higher than the surrounding surface, and a 1% horizontal slope is left on the surface. Drainage ditches are set on both sides of the foundation. S3. Concrete foundation pouring: The surveyor shall determine the length, width and height of the concrete foundation, set the position of the concrete foundation, and measure the elevation of the concrete top surface; S4. Install the steel pipe column: After the steel pipe column is hoisted, it is connected to the prefabricated bolts on the foundation through the bottom flange; S5. Installing double 40a I-beams and Bailey beams (1): hoisting the 40a I-beams and installing them on the tops of several steel pipe columns, and then installing two rows of Bailey beams (1) on the 40a I-beams. The Bailey beams (1) are required to have a span of 12.3m and a spacing of 0.45m. S6. Installing the double-jointed 25a I-beams (2): Mark the placement position of each group of 25a I-beams (2) above the Bailey beam (1), then transport the 25a I-beams (2) to the bottom of the cap beam, use a lifting vehicle to hoist the 25a I-beams (2) on one side of the Bailey beam (1), and install the 25a I-beams (2) on the Bailey beam (1). The span of the double-jointed 25a I-beams (2) is 5.5m, and the spacing is 0.5m. The cap beam is set on the 25a I-beams (2) and is located between two rows of Bailey beams (1); S7. Install square timber and formwork: Install several square timbers with a length and width of 8 cm on the 25a I-beam (2). The square timbers are required to have a span of 0.5 m and a spacing of 0.16 m. S8. Concrete pouring: Pour concrete horizontally in three layers on the square timber, pouring from both ends to the middle, and the pouring thickness of each layer is 30cm.

2. The cap beam door opening formwork construction process according to claim 1 is characterized in that: In the step S2, after the foundation treatment is completed, a 40 cm thick graded gravel foundation is made, and the graded gravel is filled in two layers. The graded gravel is heavily compacted, and the compaction degree is not less than 96%.

3. The construction process of the cap beam door opening formwork according to claim 1 is characterized in that: In the step S4, before the steel pipe column is hoisted, the elevation of the concrete top surface should be checked first to see if it is consistent with the plan, and then the steel pipe column is hoisted, the steel pipe column is preliminarily reinforced, and the final reinforcement is performed after the verticality of the steel pipe column is adjusted to meet the requirements, and finally the verticality and elevation of the steel pipe column are checked.

4. The cap beam door opening formwork construction process according to claim 1 is characterized in that: In the step S6, when hoisting the 25a I-beam (2), the hoisting point of the crane is arranged between the two groups of Bailey beams (1). Two hoisting points are set on the 25a I-beam (2), which are located at the center position of the 25a I-beam (2) in the length direction and 2m away from the end direction.

5. The construction process of the cap beam door opening formwork according to claim 1 is characterized in that: In the step S6, before hoisting the 25a I-beam (2), the ends of the two 25a I-beams (2) are connected by using short sections of steel bars.

6. The cap beam door opening formwork construction process according to claim 1 is characterized in that: In the step S8, the slump and workability of the concrete are tested before pouring, and the slump is required to be 180±20 mm.

7. The cap beam door opening formwork construction process according to claim 6 is characterized in that: During pouring, the pouring speed of concrete is controlled at 0.5-1.0m / h, and the free fall height of concrete is ensured to be no more than 2m.

8. The cap beam door opening formwork construction process according to claim 7 is characterized in that: After pouring the concrete, vibrate the concrete until it stops sinking, stops bubbling, has a flat surface, and becomes slurry.

9. The cap beam door opening formwork construction process according to claim 8, characterized in that: After vibrating the concrete, at room temperature, after the surface of the cap beam concrete has been set and solidified, cover it with non-woven fabric and sprinkle water for curing. After 24 hours, loosen the support of the side formwork to leave a gap between the formwork and the concrete surface. The concrete should be cured in the formwork for no less than three days.

10. The cap beam door opening formwork construction process according to claim 1, characterized in that: After performing the step S8, the frame is dismantled. The dismantling is carried out according to the principle of installing first and dismantling later, or installing later and dismantling first. Start from the top floor and dismantle downwards layer by layer. It is not allowed to operate simultaneously on the upper and lower floors.

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