A new type of formwork-free steel bar truss floor slab and its construction structure and construction method

Abstract

The present invention discloses a new type of formwork-free steel bar truss floor slab and its construction structure and construction method. The steel bar truss floor slab includes a bottom formwork steel plate, on which several groups of web bar steels are arranged along the transverse direction at intervals. Each group of web bar steels includes two arranged symmetrically in a V-shape. Between the upper parts of the two web bar steels in each group, a transverse upper chord steel bar is connected. The lower parts of the two web bar steels in each group are both connected with a transverse lower chord steel bar. The construction structure includes the above-mentioned formwork-free new type of steel bar truss floor slab and also includes longitudinally arranged beam formworks. The construction method is for the construction structure of the above-mentioned formwork-free new type of steel bar truss floor slab. In the present invention, the galvanized steel plate at the bottom of the truss floor slab is used as a formwork. This floor slab can save the processes and costs of formwork erection and removal, is beautiful and durable, and can reduce the on-site steel bar binding workload by about 70%, can greatly improve the construction efficiency and reduce the construction cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of the construction of floor bearing plates for buildings, and particularly relates to a new type of steel bar truss floor bearing plate without form removal, its construction structure and construction method. Background Art

[0002] With the continuous development of steel structure buildings, the traditional construction method of on-site casting slabs is difficult to keep up with the construction speed of the steel structure of the building main body, thus affecting the overall construction progress. The construction of on-site casting slabs requires the erection of formwork and scaffolding and other auxiliary facilities, resulting in an overall disconnection of the construction process. Summary of the Invention

[0003] The purpose of the present invention is: The present invention provides a new type of steel bar truss floor bearing plate without form removal, its construction structure and construction method, and solves the problem of low construction efficiency of the traditional construction method of on-site casting slabs.

[0004] In the present invention, the galvanized steel plate at the bottom of the truss floor bearing plate is used as a formwork. This floor bearing plate can save the processes and costs of formwork erection and removal, is beautiful and durable, and can reduce the on-site steel bar binding workload by about 70%, can greatly improve the construction efficiency, reduce the construction cost. In addition, the steel bars are arranged evenly, and the spacing between the upper and lower layers of steel bars and the thickness of the concrete protective layer can be fully guaranteed, creating favorable conditions for improving the construction quality of the floor slab.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A new type of steel bar truss floor bearing plate without form removal, including a bottom formwork steel plate, on which several groups of web bar steel bars are arranged horizontally and at intervals. Each group of web bar steel bars includes two arranged symmetrically in an octagonal shape. Between the upper parts of the two web bar steel bars in each group, a horizontal upper chord steel bar is connected. At the lower parts of the two web bar steel bars in each group, a horizontal lower chord steel bar is connected.

[0007] Further, the web bar steel bars include alternately arranged vertical triangular segments and horizontal U-shaped segments. The upper corner of the vertical triangular segment is connected to the upper chord steel bar, the lower two corners of the vertical triangular segment are connected to the lower chord steel bar, and the horizontal U-shaped segment is connected to the bottom formwork steel plate.

[0008] Further, the bottom formwork steel plate is a galvanized steel plate.

[0009] Further, it also includes end supports located at the ends of the upper chord steel bar and the lower chord steel bar. The end supports include mutually connected support vertical steel bars and support horizontal steel bars. The support vertical steel bars are connected between the upper chord steel bar and the bottom formwork steel plate, and the support horizontal steel bars are connected between the two lower chord steel bars.

[0010] Further, one end of the bottom formwork steel plate is provided with a fastening part A, and the other end of the bottom formwork steel plate is provided with a fastening part B that cooperates with the fastening part A.

[0011] Further, a convex platform part is provided on the bottom formwork steel plate, and the convex platform part is connected to the web bar reinforcement.

[0012] A construction structure of a new type of non - removable formwork steel bar truss floor slab includes the above - mentioned new type of non - removable formwork steel bar truss floor slab, and also includes longitudinally arranged beam formworks. The beam formworks are connected between two adjacent bottom formwork steel plates at intervals. The upper end of the beam formwork is connected to the bottom formwork steel plate. There are beam inner reinforcements extending above the bottom formwork steel plate in the beam formwork. The upper chord reinforcements and lower chord reinforcements on two adjacent bottom formwork steel plates at intervals are connected by transition reinforcements, and two directly adjacent bottom formwork steel plates are connected by fastening.

[0013] Further, it also includes a support frame. The support frame supports three end faces of the beam formwork through wooden squares, and the beam formwork and the upper wooden square are connected by iron nails.

[0014] Further, the bottom formwork steel plate is provided with slab surface reinforcements arranged in the same direction as the upper chord reinforcements.

[0015] Further, two adjacent bottom formwork steel plates at intervals are arranged in opposite directions relative to the beam formwork. The upper chord reinforcements on two adjacent bottom formwork steel plates at intervals are connected by horizontal upper chord connecting reinforcements, the lower chord reinforcements on two adjacent bottom formwork steel plates at intervals are connected by horizontal lower chord connecting reinforcements, and longitudinal distribution reinforcements are connected between the lower chord reinforcements.

[0016] Further, two adjacent bottom formwork steel plates at intervals are arranged in opposite directions relative to the beam formwork. The upper chord reinforcements on two adjacent bottom formwork steel plates at intervals are connected by horizontal support negative reinforcements, and the lower chord reinforcements on two adjacent bottom formwork steel plates at intervals are connected by horizontal distribution reinforcements.

[0017] Further, one of the two adjacent bottom formwork steel plates at intervals is arranged in the same direction as the beam formwork and the other is arranged in the opposite direction relative to the beam formwork. The upper chord reinforcements on two adjacent bottom formwork steel plates at intervals are connected by horizontal support negative reinforcements, and the lower chord reinforcements on two adjacent bottom formwork steel plates at intervals are connected by horizontal distribution reinforcements.

[0018] A construction method of a new type of non - removable formwork steel bar truss floor slab, aiming at the construction structure of the above - mentioned new type of non - removable formwork steel bar truss floor slab, includes the following steps:

[0019] Step 1, erect the support frame;

[0020] Step 2, install the beam formwork on the support frame;

[0021] Step 3: Install the steel bar truss floor slab, fix the adjacent steel bar truss floor slabs on the beam formwork, and buckle and connect the two directly adjacent steel bar truss floor slabs;

[0022] Step 4: Install the pipeline.

[0023] Step 5: Tie the steel bars.

[0024] Step 6: Inspect, accept and pour the concrete.

[0025] Advantages of the present invention:

[0026] 1. The new type of steel bar truss floor slab realizes mechanized production, which is beneficial to the uniform arrangement spacing of steel bars and the consistent thickness of the concrete protective layer, ensuring the pouring and forming quality of the concrete floor slab.

[0027] 2. The prefabricated steel bar truss floor slab can significantly reduce the on-site steel bar tying work quantity, speed up the construction progress, increase the construction safety guarantee, and realize civilized construction.

[0028] 3. The steel bar truss floor slab is one of the most common types of floor slabs. Moreover, the use of steel bar material in the steel bar truss floor slab makes it more stable and has a longer service life.

[0029] 4. Compared with ordinary profiled steel sheets, the bottom plate of the steel bar truss floor slab is only used as a formwork, and the thinnest steel sheet can be used as much as possible, and its thickness only needs to be 0.5 mm, which reduces its cost to a certain extent. At the same time, the thickness of the floor slab poured with the steel bar truss floor slab is 30 - 50 mm less than that of the traditional concrete floor slab. If the same net space is required for the building, the construction cost of 30 - 50 mm space can be saved for each floor of the building, and it has a more obvious investment-saving advantage for high-rise buildings.

[0030] 5. After the construction is completed, the steel bar truss is completely wrapped by the concrete, and the thickness of the poured concrete protective layer is uniform. Moreover, the floor is made of galvanized steel sheet, which has good anti-corrosion performance.

[0031] The main solution of the present invention and its various further alternative solutions can be freely combined to form multiple solutions, all of which are the solutions that can be adopted and claimed by the present invention; and in the present invention, (each non-conflicting option) options can be freely combined with each other and with other options. Those skilled in the art can understand that there are various combinations according to the prior art and common general knowledge after understanding the solution of the present invention, all of which are the technical solutions to be protected by the present invention, and will not be enumerated here. Description of the Drawings

[0032] Figure 1 It is the structural elevation view of the steel bar truss floor slab of the present invention.

[0033] Figure 2 This is the structural side view (section) of the steel bar truss floor slab of the present invention.

[0034] Figure 3 This is the structural side view of the end support of the steel bar truss floor slab of the present invention.

[0035] Figure 4 This is the layout schematic diagram of the surface reinforcement of the construction structure of the present invention.

[0036] Figure 5 This is the structural schematic diagram of Construction Structure Node 1 of the present invention.

[0037] Figure 6 This is the structural schematic diagram of Construction Structure Node 2 of the present invention.

[0038] Figure 7 This is the structural schematic diagram of Construction Structure Node 3 of the present invention.

[0039] Figure 8 This is the structural schematic diagram of the buckling structure of the steel bar truss floor slab of the construction structure of the present invention.

[0040] In the figure: 1 - upper chord steel bar, 2 - lower chord steel bar, 3 - web bar steel bar, 4 - bottom formwork steel plate, 5 - end support, 6 - vertical support steel bar, 7 - horizontal support steel bar, 8 - buckling part A, 9 - buckling part B, 10 - convex part, 11 - surface reinforcement, 12 - support frame, 13 - beam formwork, 14 - wooden square, 15 - steel bar in beam, 16 - upper chord connecting steel bar, 17 - lower chord connecting steel bar, 18 - iron nail, 19 - distribution steel bar, 20 - support negative steel bar. Detailed implementation manners

[0041] The following non - restrictive embodiments are used to illustrate the present invention.

[0042] Embodiment 1

[0043] Refer to Figures 1 to 3 As shown, a new - type steel bar truss floor slab without formwork removal includes an upper chord steel bar 1, a lower chord steel bar 2, a web bar steel bar 3, a bottom formwork steel plate 4, an end support 5 (including a vertical support steel bar 6 and a horizontal support steel bar 7), a buckling part A 8, a buckling part B 9 and a convex part 10.

[0044] Refer to Figure 1 and Figure 2As shown, the bottom formwork steel plate 4 is a 0.5-mm-thick galvanized steel plate and is used as the bottom formwork. A number of groups of web bar steels 3 (with a diameter of 4.5 mm) are arranged horizontally and at intervals on the bottom formwork steel plate 4. Each group of web bar steels 3 includes two arranged symmetrically in an octagonal shape. Between the upper parts of the two web bar steels 3 in each group, a horizontally arranged upper chord steel bar 1 (with a diameter of 10 mm / 8 mm) is welded. At the lower parts of the two web bar steels 3 in each group, a horizontally arranged lower chord steel bar 2 (with a diameter of 10 mm / 8 mm) is welded.

[0045] Each web bar steel 3 includes alternately arranged vertical triangular segments and horizontal U-shaped segments. The upper corner of the vertical triangular segment is welded to the upper chord steel bar 1, the lower two corners of the vertical triangular segment are welded to the lower chord steel bar 2, and the horizontal U-shaped segment is welded to the convex part 10 on the bottom formwork steel plate 4, thereby forming the upper steel bar truss structure.

[0046] Reference Figure 3 As shown, it also includes end supports 5 at the ends of the upper chord steel bar 1 and the lower chord steel bar 2. The end support 5 includes a support vertical steel bar 6 and a support horizontal steel bar 7 that are welded to each other. The support vertical steel bar 6 is welded between the upper chord steel bar 1 and the bottom formwork steel plate 4, and the support horizontal steel bar 7 is welded between the two lower chord steel bars 2. The end supports 5 are used to support and fix the ends of the upper chord steel bar 1 and the lower chord steel bar 2.

[0047] One end of the bottom formwork steel plate 4 is provided with a fastening part A 8, and the other end of the bottom formwork steel plate 4 is provided with a fastening part B 9 that cooperates with the fastening part A 8. The fastening connection between the fastening part A 8 and the fastening part B 9 is used to realize the connection between two directly adjacent bottom formwork steel plates 4 and avoid leakage of slurry from the connection gap. The bottom formwork steel plate 4 is also provided with a convex part 10, and the convex part 10 is welded to the web bar steel 3.

[0048] Embodiment 2

[0049] Reference Figures 4 to 8 As shown, a construction structure of a new type of non-removable formwork steel bar truss floor slab includes the new type of non-removable formwork steel bar truss floor slab of Embodiment 1, and also includes surface steel bars 11, support frames 12, beam formworks 13, wooden squares 14, beam internal steel bars 15, upper chord connecting steel bars 16, lower chord connecting steel bars 17, iron nails 18, distribution steel bars 19, and support negative steel bars 20.

[0050] The support frame 12 adopts a disc - button type steel pipe support frame to support the beam formwork 13, thereby realizing the fixed installation of the beam formwork 13. The beam formwork 13 is longitudinally arranged, and at the same time, the beam formwork 13 is connected between two adjacent bottom formwork steel plates 4 with a gap (that is, there are two bottom formwork steel plates 4 with a gap). The upper end of the beam formwork 13 is connected to the bottom formwork steel plate 4, and the beam formwork 13 is used to support the bottom formwork steel plate 4 to realize the fixed installation of the steel bar truss floor slab. The beam formwork 13 is provided with beam internal steel bars 15 extending above the bottom formwork steel plate 4, and the beam internal steel bars 15 are the internal steel bar skeletons after the beam structure is poured.

[0051] The upper chord steel bars 1 and the lower chord steel bars 2 on two adjacent bottom formwork steel plates 4 with a gap are connected by transition steel bars. The steel bar trusses on two adjacent bottom formwork steel plates 4 with a gap are connected into one body by the transition steel bars to ensure that the overall structure is more firm. The transition steel bars can also be connected to the beam internal steel bars 15 to further enhance the connection strength.

[0052] Reference Figure 8 As shown in the reference, two directly adjacent bottom formwork steel plates 4 (that is, two bottom formwork steel plates 4 with overlapping joints) are connected by snap - fit. That is, the snap - fit part A 8 of one bottom formwork steel plate 4 is snap - fit connected to the snap - fit part B 9 of another bottom formwork steel plate 4. With this kind of bent snap - fit structure, not only can the ends of the two bottom formwork steel plates 4 be connected, but also the sealing effect at the joint can be realized by using multiple bent structures.

[0053] Reference Figure 4 As shown in the reference, the formwork surface steel bars 11 arranged in the same direction as the upper chord steel bars 1 are provided on the bottom formwork steel plate 4. When the spacing a of the formwork surface steel bars 11 is affected by the truss upper chord steel bars, the steel bars near the upper chord steel bars can be directly tied together with it. At this time, the spacing is b, and then the spacing of the steel bars behind continues to be a.

[0054] The beam formwork 13 has a U - shaped cross - section structure. A wooden square 14 is provided on the outside of the beam formwork 13. The support frame 12 supports three end faces of the beam formwork 13 through the wooden square 14, and the bottom formwork steel plate 4 and the upper wooden square 14 are connected by iron nails 18 to realize the support of the beam formwork 13 to the bottom formwork steel plate 4.

[0055] There are three relative position relationships between two adjacent bottom formwork steel plates 4 with a gap with respect to the beam formwork 13. Each position relationship corresponds to a different connection node, and it is described with the beam formwork 13 being longitudinally arranged.

[0056] Reference Figure 5As shown in the figure, for the first type, the two adjacent bottom formwork steel plates 4 are arranged in the opposite direction relative to the beam formwork 13. The upper chord steel bars 1 on the two adjacent bottom formwork steel plates 4 are tied and connected by the transverse upper chord connecting steel bars 16. The upper chord connecting steel bars 16 are in an inverted U-shaped structure. The lower chord steel bars 2 on the two adjacent bottom formwork steel plates 4 are tied and connected by the transverse lower chord connecting steel bars 17. The lower chord connecting steel bars 17 are in a positive U-shaped structure. The longitudinal distribution steel bars 19 are tied between the lower chord steel bars 2.

[0057] Reference Figure 6 As shown in the figure, for the second type, the two adjacent bottom formwork steel plates 4 are arranged in the opposite direction relative to the beam formwork 13. The upper chord steel bars 1 on the two adjacent bottom formwork steel plates 4 are connected by the transverse support negative steel bars 20. The support negative steel bars 20 are in an inverted U-shaped structure. The lower chord steel bars 2 on the two adjacent bottom formwork steel plates 4 are connected by the transverse distribution steel bars 19, and the distribution steel bars 19 at this node are arranged in a continuous length.

[0058] Reference Figure 7 As shown in the figure, for the third type, one of the two adjacent bottom formwork steel plates 4 is arranged in the positive direction relative to the beam formwork 13, and the other is arranged in the opposite direction relative to the beam formwork 13. The upper chord steel bars 1 on the two adjacent bottom formwork steel plates 4 are connected by the transverse support negative steel bars 20. The support negative steel bars 20 are in an inverted U-shaped structure. The lower chord steel bars 2 on the two adjacent bottom formwork steel plates 4 are connected by the transverse distribution steel bars 19, and the distribution steel bars 19 at this node only extend to the end position inside the bottom formwork steel plate 4 arranged in the opposite direction.

[0059] Example 3

[0060] Reference Figures 1 to 8 As shown in the figure, a construction method for a new type of non-removable formwork steel bar truss floor slab. For the construction structure of the new type of non-removable formwork steel bar truss floor slab in Example 2, it includes the following steps.

[0061] Step 1, erection of the support frame: Erection a full hall support frame before installing the steel bar truss floor slab. The longitudinal and transverse spacing of the vertical poles is 1200 mm, the step distance is 1500 mm. The distance from the bottom surface of the vertical pole to the floor slab is ≤ 550 mm. The length of the adjustable support base of the formwork support extending from the top horizontal bar is ≤ 650 mm, and the exposed length of the screw rod is ≤ 400 mm. The length of the adjustable support base inserted into the vertical pole shall not be less than 150 mm. The top of the vertical pole adopts an adjustable support, and the number of steel pipes inside the support is two.

[0062] Step 2, installation of the beam formwork on the support frame: Using the support frame as the support foundation, install and fix the beam formwork, and support the outside of the beam formwork with wooden squares to prevent the beam formwork from bulging after pouring.

[0063] Step 3, Install the steel bar truss floor formwork: After the beam formwork is installed and before the steel bar truss floor formwork is laid, set the reference line for laying the formwork at the starting position shown in the drawing. Align with the reference line, install the first board, and then install other boards in sequence, using non-standard boards for the ending.

[0064] Fix the adjacent steel bar truss floor formworks to the beam formwork. At the connection between the steel bar truss floor formwork and the beam formwork, the galvanized bottom formwork steel plate is flush with the beam edge on the side formwork of the beam. After the steel bar truss floor formwork is in place, nail the bottom formwork steel plate at its end to the side formwork of the beam or column firmly, with the nail spacing ≤ 200 mm, and use the beam formwork to support and install the steel bar truss floor formwork.

[0065] The directly adjacent two steel bar truss floor formworks are connected by snap-fastening. The connection between the floor formworks adopts the snap-fastening method, and the hooks between the boards are tightly connected to ensure no leakage of concrete during pouring. At the same time, pay attention to the consistency of the plate laying direction.

[0066] Step 4, Pipeline laying: For the reserved embedding of electrical junction boxes, they can be fixed on the galvanized plate first. Drilling holes with a diameter of Φ30 mm and below is allowed. Drilling should be careful to avoid deformation of the steel bar truss floor formwork and the bottom formwork of the truss and the galvanized bottom formwork steel plate from being welded off, which may affect the appearance or cause leakage of concrete. When laying pipelines, it is prohibited to randomly move or cut any steel bars of the steel bar truss.

[0067] Step 5, Tie steel bars: Place the steel bars in the beam, and tie the surface steel bars parallel to the direction of the steel bar truss floor formwork and the distribution steel bars (bottom steel bars) perpendicular to the direction of the steel bar truss floor formwork.

[0068] Step 6, Inspection, acceptance and pouring of concrete: Before the concrete is poured, the installation of the steel bar truss floor formwork and other projects should be completed and passed the acceptance. It is necessary to remove the sundries (including the porcelain rings on the stud bolts), dust, grease, etc. on the floor formwork, and finally pour the concrete and carry out curing.

[0069] The basic example of the present invention and its various further selected examples can be freely combined to form multiple embodiments, all of which are the embodiments that can be adopted and claimed by the present invention. In the solution of the present invention, each selected example can be arbitrarily combined with any basic example and selected example.

[0070] The above are only the preferred embodiments of the present invention, and are not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A construction structure of a new type of formwork-free steel bar truss floor slab, including the formwork-free new type of steel bar truss floor slab, which comprises a bottom formwork steel plate (4), and is characterized in that: On the bottom formwork steel plate (4), there are several groups of web bar steels (3) arranged transversely and at intervals. Each group of web bar steels (3) includes two arranged symmetrically in an inverted V shape. Between the upper parts of the two web bar steels (3) in each group, there is an upper chord steel (1) arranged transversely. At the lower parts of the two web bar steels (3) in each group, there is a lower chord steel (2) arranged transversely. The web bar steel (3) includes alternately arranged vertical triangular segments and horizontal U-shaped segments. The upper corner of the vertical triangular segment is connected to the upper chord steel (1), the lower two corners of the vertical triangular segment are connected to the lower chord steel (2), and the horizontal U-shaped segment is connected to the bottom formwork steel plate (4). The bottom formwork steel plate (4) is a galvanized steel plate. This floor slab formwork also includes end supports (5) at the ends of the upper chord steel (1) and the lower chord steel (2). The end support (5) includes a support vertical steel (6) and a support horizontal steel (7) connected to each other. The support vertical steel (6) is connected between the upper chord steel (1) and the bottom formwork steel plate (4), and the support horizontal steel (7) is connected between the two lower chord steels (2). One end of the bottom formwork steel plate (4) is provided with a fastening part A (8), and the other end of the bottom formwork steel plate (4) is provided with a fastening part B (9) that cooperates with the fastening part A (8). On the bottom formwork steel plate (4), there is a convex part (10), and the convex part (10) is connected to the web bar steel (3). This construction structure also includes a longitudinally arranged beam formwork (13). The beam formwork (13) is connected between two adjacent bottom formwork steel plates (4) at intervals. The upper end of the beam formwork (13) is connected to the bottom formwork steel plate (4). Inside the beam formwork (13), there is a beam internal steel (15) extending above the bottom formwork steel plate (4). Between the upper chord steel (1) and the lower chord steel (2) on two adjacent bottom formwork steel plates (4) at intervals, they are connected by transition steels. Between two directly adjacent bottom formwork steel plates (4), they are connected by fastening. This construction structure also includes a support frame (12). The support frame (12) supports three end faces of the beam formwork (13) through a wooden square (14). Between the beam formwork (13) and the upper wooden square (14), they are connected by nails (18). On the bottom formwork steel plate (4), there is a slab surface steel (11) arranged in the same direction as the upper chord steel. Two adjacent bottom formwork steel plates (4) at intervals are arranged in opposite directions relative to the beam formwork (13). Between the upper chord steels (1) on two adjacent bottom formwork steel plates (4) at intervals, they are connected by a transverse upper chord connecting steel (16). Between the lower chord steels (2) on two adjacent bottom formwork steel plates (4) at intervals, they are connected by a transverse lower chord connecting steel (17). Between the lower chord steels (2), there is a longitudinally arranged distribution steel (19). Two adjacent bottom formwork steel plates (4) at intervals are arranged in opposite directions relative to the beam formwork (13). Between the upper chord steels (1) on two adjacent bottom formwork steel plates (4) at intervals, they are connected by a transverse support negative steel (20). Between the lower chord steels (2) on two adjacent bottom formwork steel plates (4) at intervals, they are connected by a transverse distribution steel (19). One of the two adjacent bottom formwork steel plates (4) is arranged forward relative to the beam formwork (13), and the other is arranged backward relative to the beam formwork (13). The upper chord steel bars (1) on the two adjacent bottom formwork steel plates (4) are connected by a transverse support negative bar (20), and the lower chord steel bars (2) on the two adjacent bottom formwork steel plates (4) are connected by a transverse distribution bar (19).

2. A construction method for a new type of formwork-free steel bar truss floor slab, aiming at the construction structure of the new type of formwork-free steel bar truss floor slab described in claim 1, characterized in that, It includes the following steps: Step 1, erection of the support frame; Step 2, installation of the beam formwork on the support frame; Step 3, installation of the steel bar truss floor slab, fixing the adjacent steel bar truss floor slabs on the beam formwork, and buckling and connecting the two directly adjacent steel bar truss floor slabs; Step 4, laying of pipeline; Step 5, tying of steel bars; Step 6, inspection, acceptance and pouring of concrete.

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