Underground diaphragm wall and pile foundation combined structure for reinforcing wharf and implementation method of underground diaphragm wall and pile foundation combined structure

Abstract

The invention discloses an underground diaphragm wall and pile foundation combined structure for reinforcing a wharf and an implementation method of the underground diaphragm wall and pile foundation combined structure for reinforcing the wharf. The underground diaphragm wall and pile foundation combined structure for reinforcing the wharf comprises a front wall, a pile foundation, a breast wall and an overhanging beam, and the front wall is arranged behind an existing wharf structure; the pile foundation is arranged behind the front wall; the breast wall is arranged at the top of the front wall; a cantilever part is arranged on the sea side of the overhanging beam; the overhanging beams are perpendicular to the breast wall and are arranged along the breast wall at intervals; the middle of the overhanging beam is connected with a breast wall, the rear portion of the overhanging beam is connected with a pile foundation, and a cantilever part of the overhanging beam is located on the upper portion of an existing wharf structure. The existing wharf reinforcing technology can be improved, and the purpose of reinforcing the wharf on the basis of not damaging the existing structure is achieved by implementing the whole structure on the upper portion and the landside of the existing structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of building structures in coastal engineering and port engineering, and particularly relates to a diaphragm wall and pile foundation combined structure for strengthening a wharf and an implementation method thereof. Background Art

[0002] With the rapid development of ports, the trend of ship enlargement is extremely obvious. For the existing old, small wharves in the port area, it is urgent to change the current situation. Some of these wharves are returned to the city, and the other part is upgraded and transformed.

[0003] According to the requirements of current specifications, when changing the use, it is necessary to calculate its safety and durability in accordance with the current specifications. The wharves built in the early years are mostly unable to meet the requirements of current specifications in terms of safety and durability due to factors such as lack of basic data, less design experience, and economic difficulties.

[0004] With the in-depth implementation of the concepts of environmental protection and green development, many existing reinforcement and transformation schemes cannot be implemented. In particular, some common structural schemes involving new sea use either require a long approval and demonstration cycle or are strictly prohibited from implementation. For wharves with certain historical value, they need to be continuously protected, and it is required that the reinforcement scheme cannot damage the original main structure, resulting in higher requirements for the structural scheme. However, the existing wharf transformation schemes cannot meet the above requirements. Summary of the Invention

[0005] The purpose of the present invention is to provide a diaphragm wall and pile foundation combined structure for strengthening a wharf and an implementation method thereof, so as to improve the existing wharf strengthening technology. By implementing the overall structure on the upper part and the land side of the existing structure, the purpose of strengthening the wharf can be achieved without damaging the existing structure.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a diaphragm wall and pile foundation combined structure for strengthening a wharf, including a front wall, pile foundations, a breast wall, and a cantilever beam. The front wall is arranged behind the existing wharf structure; the pile foundations are arranged behind the front wall; the breast wall is arranged on the top of the front wall; a cantilever part is provided on the sea side of the cantilever beam; the cantilever beam is perpendicular to the breast wall and is arranged at intervals along the breast wall; the middle part of the cantilever beam is connected to the breast wall, the rear part of the cantilever beam is connected to the pile foundations, and the cantilever part of the cantilever beam is located on the upper part of the existing wharf structure.

[0008] The diaphragm wall and pile foundation combined structure for strengthening a wharf of the present invention strengthens the existing wharf structure through the pile foundations and the cantilever beam, which is beneficial to protecting the existing wharf structure and can also ensure that the wharf continues to function properly in the future.

[0009] Preferably, the top of the pile foundation is connected to the pile cap, and the cantilever beam is connected to the pile cap through a fixed support or a sliding support.

[0010] Preferably, the front wall is a diaphragm wall, cast-in-place pile row or sheet pile.

[0011] Preferably, an anchor wall is arranged behind the pile foundation, and the top of the anchor wall is connected to the breast wall through the tie rod.

[0012] Preferably, the anchor wall is a diaphragm wall, cast-in-place pile row or sheet pile.

[0013] Preferably, there are at least two tie rods and at least two cantilever beams; the tie rods and the cantilever beams are arranged at uniform intervals.

[0014] Preferably, the front wall and the pile foundation are located in the soil mass.

[0015] Preferably, a filter layer and drainage holes are arranged at the extremely low water level position behind the front wall.

[0016] In a second aspect, the present invention provides an implementation method for the diaphragm wall plus pile foundation combined structure for strengthening a wharf according to the first aspect of the present invention, including the following steps:

[0017] Excavate to form a working surface, and complete the construction of the front wall behind the existing wharf structure; at the same time, carry out the construction of the pile foundation;

[0018] Integrally pour the breast wall and the cantilever beam;

[0019] Backfill to form the wharf surface.

[0020] Preferably, according to the front water depth, waves, geology and subsequent service loads, calculate to determine the setting of the anchor wall and the tie rod, determine the parameters of the anchor wall and the tie rod, and determine the connection method between the pile foundation and the cantilever beam;

[0021] After the construction of the pile foundation is completed, construct the pile cap on the top of the pile foundation, and at the same time, carry out the construction of the anchor wall; connect the anchor wall and the front wall with a tie rod, and connect the pile foundation and the cantilever beam;

[0022] After integrally pouring the breast wall and the cantilever beam, tension the tie rod after the concrete strength reaches the design requirements.

[0023] The diaphragm wall plus pile foundation combined structure for strengthening a wharf and its implementation method provided by the present invention have the following beneficial effects:

[0024] The diaphragm wall and pile foundation combined structure for strengthening a wharf provided by the present invention and its implementation method adopt an effective combination of a sheet pile wharf structure, a pile foundation, and a cantilever beam, improving the existing wharf strengthening technology, achieving the effects of structural safety, controllable construction quality, short construction period, and minimal impact on the marine environment. By implementing the overall structure on the upper part and the land side of the existing structure, it can achieve the purpose of strengthening the wharf without damaging the existing structure, ensuring that the wharf can continue to function properly in the future, and effectively supplementing and improving the existing wharf renovation plan.

[0025] The diaphragm wall and pile foundation combined structure for strengthening a wharf provided by the present invention and its implementation method have the least impact on the existing wharf structure compared with the traditional wharf strengthening structures that only strengthen the wharf structure itself and use a single structure for strengthening and renovation. Moreover, during the subsequent service period except for the construction period, it no longer relies on the existing wharf structure to function, which is conducive to solving the safety and durability of the wharf and can ensure the long-term existence of the current structure. Especially for some wharves with historical value, it is conducive to their good preservation. The entire renovation process of the existing wharf structure is carried out on land, which is conducive to ensuring construction quality, construction safety, and construction progress. During the construction process, no ship machinery and equipment are required, reducing maritime supervision costs and avoiding affecting the marine environment. Except for the backfill materials about 5m on the surface being greatly disturbed, the entire structure is less affected by the renovation. Even if the existing wharf structure is damaged later, it can be cleaned up in time.

[0026] The diaphragm wall and pile foundation combined structure for strengthening a wharf of the present invention and its implementation method can greatly increase the distance between the front line and the front wall of the existing wharf structure compared with the traditional sheet pile structure, effectively protecting the main body structure of the existing wharf. When the horizontal load is small and the anchor wall and tie rod are not set, the pile foundation under the cantilever beam can provide horizontal resistance. At this time, a fixed connection is adopted between the cantilever beam and the pile foundation to provide a certain level of resistance through the fixed connection, playing a role in reducing the horizontal displacement of the structure. When the overall horizontal load of the structure is large, the connection method between the cantilever beam and the pile foundation can be changed to a sliding connection to avoid the pile foundation following the front wall to generate displacement and reduce the internal force of the pile foundation itself. Compared with the traditional sheet pile without anchor, the diaphragm wall and pile foundation combined structure for strengthening a wharf of the present invention has a smaller horizontal displacement, is convenient for construction, and is easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the front view of the diaphragm wall and pile foundation combined structure for strengthening a wharf provided by an embodiment of the present invention.

[0028] Figure 2 is the top view of the diaphragm wall and pile foundation combined structure for strengthening a wharf provided by an embodiment of the present invention.

[0029] Figure 3It is the left view of the diaphragm wall and pile foundation combined structure for strengthening a wharf provided by an embodiment of the present invention.

[0030] Figure 4 It is the right view of the diaphragm wall and pile foundation combined structure for strengthening a wharf provided by an embodiment of the present invention.

[0031] Figure 5 It is the flowchart of the implementation method of the diaphragm wall and pile foundation combined structure for strengthening a wharf provided by an embodiment of the present invention.

[0032] Figure 6 It is the flowchart of the implementation method of the diaphragm wall and pile foundation combined structure for strengthening a wharf provided by another embodiment of the present invention.

[0033] Figure 7 It is the model load distribution diagram of the implementation method of the diaphragm wall and pile foundation combined structure for strengthening a wharf provided by an embodiment of the present invention.

[0034] Reference numerals in the figure:

[0035] 1. Front wall, 2. Anchor wall, 3. Tie rod, 4. Breast wall, 5. Cantilever beam, 6. Pile foundation, 7. Pile cap, 8. Existing wharf structure. Specific implementation manners

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0037] Embodiment 1

[0038] Please refer to Figures 1 to 4 , this embodiment provides a diaphragm wall and pile foundation combined structure for strengthening a wharf, including a front wall 1, a pile foundation 6, a breast wall 4 and a cantilever beam 5. The front wall 1 is arranged behind the existing wharf structure 8; the pile foundation 6 is arranged behind the front wall 1; the breast wall 4 is arranged on the top of the front wall 1; the sea side of the cantilever beam 5 is provided with a cantilever part; the cantilever beam 5 is perpendicular to the breast wall 4 and is arranged at intervals along the breast wall 4; the middle part of the cantilever beam 5 is connected to the breast wall 4, the rear part of the cantilever beam 5 is connected to the pile foundation 6, and the cantilever part of the cantilever beam 5 is located above the existing wharf structure 8.

[0039] In the prior art, the existing wharf structure 8 is strengthened by an existing sheet pile scheme. The sheet pile will be located about 0.5 - 1 m behind the current front line, which will damage the existing structure and a large amount of waste will be generated and enter the sea during the construction process, requiring cleaning. During the construction process, it is also necessary to set up enclosures to prevent the spread of pollutants. However, for the diaphragm wall and pile foundation combined structure for strengthening a wharf in this embodiment, an effective combination of structures such as the front wall 1, the pile foundation 6 and the cantilever beam 5 is adopted. On the premise of keeping the position of the existing front line of the wharf unchanged and not affecting the main body of the existing wharf structure, the strengthening structure is arranged 9.5 - 10 m behind the existing front line of the wharf.

[0040] The diaphragm wall and pile foundation combined structure for strengthening a wharf in this embodiment can avoid interference with the existing wharf structure 8; that is, the main body of the existing wharf structure 8 does not need to be demolished, which is equivalent to transforming the sea-related project into an onshore project, thus greatly reducing the construction difficulty of the diaphragm wall and pile foundation combined structure for strengthening the wharf of the present invention and greatly reducing the difficulty of reconstructing the existing wharf structure 8, which is conducive to protecting the existing wharf structure 8. It can improve the existing wharf strengthening technology. By implementing the overall structure on the upper part and the land side of the wharf structure 8, the purpose of strengthening the wharf can be achieved without damaging the existing wharf structure 8.

[0041] Among them, Figure 1 and Figure 2 in the figure, the left side is the front side, that is, the sea side; the right side is the rear side, that is, the land side. Figure 3 It represents the structure on one side of the front wall 1. Figure 4 It represents the structure on one side of the cantilever beam 4 and the pile foundation 6.

[0042] The breast wall 4 and the cantilever beam 5 can adopt a reinforced concrete structure. The cantilever beam 5 is a cantilever structure on the sea side, and pile foundations 6 are arranged at the lower part on the land side. The pile foundations 6 can adopt precast concrete pipe piles, steel pipe piles or cast-in-place piles.

[0043] Specifically, the top of the pile foundation 6 is connected to the pile cap 7, and the cantilever beam 5 is connected to the pile cap 7 through a fixed support or a sliding support.

[0044] That is, the cantilever beam 5 and the pile foundation 6 can be directly connected, or the cantilever beam 5 can also be indirectly connected to the pile foundation 6 by setting an intermediate structure, and the intermediate structure can adopt the pile cap 7.

[0045] The diaphragm wall and pile foundation combined structure for strengthening a wharf in this embodiment can balance the force of the cantilever beam 5 through the pile foundation 6; the front wall 1 is affected by the soil pressure, and the horizontal resistance is provided by the tie rod 3 to reduce the deformation and internal force of the front wall. Therefore, adopting a fixed connection constraint between the pile foundation 6 and the cantilever beam 5 can better reduce the horizontal displacement of the front wall 1, but it will cause the internal forces of the pile foundation 6 and the front wall 1 to increase accordingly. Therefore, the setting of the constraint method needs to be selected by calculating the structural force. In this case, a fixed connection constraint is adopted.

[0046] When a fixed connection constraint is adopted between the cantilever beam 5 and the pile foundation 6, the horizontal resistance provided by the pile foundation 6 can reduce the overall horizontal displacement of the diaphragm wall and pile foundation combined structure for strengthening the wharf. For example, the original overall structural horizontal displacement is 5 - 7 cm, and through the pile foundation 6, the horizontal displacement can be reduced to 3 - 5 cm.

[0047] If only the pile foundation 6 under the cantilever beam 5 needs to bear the vertical force, the pile cap 7 at the top of the pile foundation 6 can be set as a sliding support. At this time, the pile foundation 6 only bears the uplift force and the pile pressing force, and no longer bears the horizontal force. That is, the pile foundation 6 will not reduce the displacement of the front wall 1.

[0048] Specifically, the front wall 1 is a diaphragm wall, cast-in-place pile row or sheet pile.

[0049] Among them, the sheet pile can be a steel sheet pile or a concrete sheet pile.

[0050] Specifically, an anchor wall 2 is arranged behind the pile foundation 6, and the top of the anchor wall 2 is connected to the breast wall 4 through a tie rod 3.

[0051] Among them, the tie rod 3 is arranged between the front wall 1 and the anchor wall 2.

[0052] Moreover, the anchor wall 2 is a diaphragm wall, cast-in-place pile row or sheet pile.

[0053] Among them, the anchor wall 2 can adopt the same structure as the front wall 1.

[0054] Moreover, there are at least two tie rods 3.

[0055] Moreover, there are at least two cantilever beams 5.

[0056] Among them, the cantilever beams 5 can be arranged at equal intervals.

[0057] Moreover, the tie rods 3 and the cantilever beams 5 are arranged at uniform intervals.

[0058] Among them, the breast wall 4 is located at the top of the front wall 1, the cantilever beam 5 and the breast wall 4 are perpendicular and cross each other, and are integrally cast. A plurality of cantilever beams 5 are arranged at intervals in the direction perpendicular to the axis of the breast wall 4.

[0059] Specifically, the front wall 1 and the pile foundation 6 are located in the soil mass, and the action of the soil mass can be simplified as a spring in the calculation.

[0060] Specifically, a filter layer and drainage holes are arranged at the extremely low water level position behind the front wall 1.

[0061] For the diaphragm wall and pile foundation combined structure of the reinforced wharf in this embodiment, specifically, the elevation of the wharf top surface is 4.0 m, the elevation of the front bottom is -10.0 m, and the extreme high water level is 3.0 m. The front wall 1 is a cast-in-place pile with a diameter of 1.2 m arranged continuously, and the pile bottom elevation is -22.5 m. The top of the front wall 1 is a cast-in-place reinforced concrete breast wall 4 with a width of 2.2 m. The breast wall 4 and the cantilever beam 5 are integrally cast in place. The width of the cantilever beam 5 is 1.2 m, and the center spacing is 4.5 m. The sea side of the cantilever beam 5 is a cantilever structure with a cantilever length of 9.5 m. This cantilever length refers to the distance between the sea side end of the cantilever beam 5 and the center position of the front wall 1. The cantilever beam 5 extends 11.1 m towards the land side, and a pile cap 7 and a pile foundation 6 are arranged at the lower part at the 10 m position. The pile foundation 6 uses a cast-in-place pile with a diameter of 1.2 m. There is a consolidation constraint between the cantilever beam 5, the pile cap 7 and the pile foundation 6. An anchor wall 2 is arranged at a position 31.2 m away from the front wall. The anchor wall 2 uses a row of cast-in-place piles with a diameter of 1.2 m. The anchor wall 2 and the front wall 1 are connected by a tie rod 3. The tie rod 3 is a 550-type steel with a diameter of 75 mm, and the spacing of the tie rod 3 is 1.2 m.

[0062] Embodiment 2

[0063] As Figure 5 shown, this embodiment provides an implementation method for the diaphragm wall and pile foundation combined structure of the reinforced wharf described in Embodiment 1, including the following steps:

[0064] Step S1, excavate to form a working surface, and complete the construction of the front wall 1 behind the existing wharf structure 8; at the same time, construct the pile foundation 6;

[0065] Step S2, integrally pour the breast wall 4 and the cantilever beam 5;

[0066] Step S3, backfill to form the wharf surface.

[0067] Specifically, as Figure 6 shown, before performing Step S1, perform Step S11. According to the front water depth, waves, geology and subsequent use loads, calculate to determine the setting of the anchor wall 2 and the tie rod 3, and determine the parameters of the anchor wall 2 and the tie rod 3, and determine the connection method between the pile foundation 6 and the cantilever beam 5;

[0068] Among them, the parameters include the distance between the anchor wall 2 and the front wall 1, the penetration depth of the anchor wall 2, the spacing of the tie rod 3, the material and diameter of the tie rod 3.

[0069] In Step S2, after the construction of the pile foundation 6 is completed, construct the pile cap 7 on the top of the pile foundation 6, and at the same time, construct the anchor wall 2; connect the anchor wall 2 and the front wall 1 with the tie rod 3, and connect the pile foundation 6 and the cantilever beam 5;

[0070] After the integral casting of the breast wall 4 and the cantilever beam 5 in step S2 is completed, proceed to step S21. After the concrete strength reaches the design requirement, tension the tie rod 3. Then proceed to step S3 to backfill and form the quay surface.

[0071] For the construction method of the diaphragm wall and pile foundation combined structure for strengthening a quay provided in this embodiment, specifically, the soil layer distribution of the soil mass from top to bottom is successively gravelly sand (to -9.03 m), ①1 silty clay (to -10.03 m), ①2 silt (to -12.93 m), ②1 silty clay (-15.23 m), ②2 coarse gravelly sand (to -27.0 m). The indexes of each soil layer are shown in Table 1 below:

[0072] Table 1. Physical and mechanical indexes of each soil layer

[0073]

[0074] The quay load is a uniform load of 10 kPa, and the wave elements of the wave are adopted as shown in Table 2 below.

[0075] Table 2. Wave elements at the quay front

[0076]

[0077] A three-dimensional finite element model can be established using abaqus software for calculation. The soil mass is on the seaward side of the front wall 1 and the pile foundation 6. In the calculation, the action of the soil mass can be simplified as a spring, and the spring is determined according to the indexes of the soil mass at different elevations and other external loads; add earth pressure at the rear side of the front wall 1 and the pile foundation 6.

[0078] Among them, the soil layer starts from the ground downwards. The distribution of the soil mass simplified as a spring is as follows: the spring on the seaward side of the front wall 1 starts to be calculated from the elevation of the front edge bottom, and for the pile foundation 6, springs are set from the pile top to the pile bottom. A filter layer can be set at the rear side of the front wall 1 according to the tide level situation to reduce the water pressure difference between the front side and the rear side of the front wall 1.

[0079] Figure 7 It is the load distribution diagram of the model. The main calculation results are as shown in Tables 3 to 6 below: Table 3. Internal force calculation result table of the breast wall 4

[0080]

[0081] Table 4. Internal force calculation result table of the cantilever beam 5

[0082]

[0083] Table 5. Calculation result table of the front wall 1 and the anchor wall 2

[0084]

[0085] Table 6. Force calculation result table of the tie rod 3

[0086] Calculation item Calculation result Tie rod force (unit: kN) 1275.7

[0087] The above embodiments are merely examples given for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

[0088] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0089] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to has a specific orientation, is constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0090] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mount", "connect", "couple" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

Claims

1. A combined structure of diaphragm wall and pile foundation for strengthening a wharf, characterized in that Comprising: A front wall, arranged behind the existing wharf structure; Pile foundations, arranged behind the front wall; A breast wall, arranged on the top of the front wall; A cantilever beam, with a cantilever part arranged on its sea side; the cantilever beam is perpendicular to the breast wall and arranged at intervals along the breast wall; the middle part of the cantilever beam is connected to the breast wall, the rear part of the cantilever beam is connected to the pile foundations, and the cantilever part of the cantilever beam is located above the existing wharf structure.

2. The diaphragm wall and pile foundation combined structure for strengthening a wharf according to claim 1, wherein, The top of the pile foundations is connected to a pile cap, and the cantilever beam is connected to the pile cap through a fixed support or a sliding support.

3. The diaphragm wall and pile foundation combined structure for strengthening a wharf according to claim 1, wherein The front wall is a diaphragm wall, a cast-in-place pile row or a sheet pile.

4. The diaphragm wall and pile foundation combined structure for strengthening a wharf according to claim 1, characterized in that, An anchor wall is arranged behind the pile foundations, and the top of the anchor wall is connected to the breast wall through the tie rod.

5. The diaphragm wall and pile foundation combined structure for strengthening a wharf according to claim 4, wherein The anchor wall is a diaphragm wall, a cast-in-place pile row or a sheet pile.

6. The diaphragm wall and pile foundation combined structure for strengthening a wharf according to claim 4, characterized in that, There are at least two tie rods and at least two cantilever beams; the tie rods and the cantilever beams are arranged at uniform intervals.

7. The diaphragm wall and pile foundation combined structure for strengthening a wharf according to any one of claims 1-6, characterized in that The front wall and the pile foundations are located in the soil mass.

8. The diaphragm wall and pile foundation combined structure for strengthening a wharf according to any one of claims 1-6, characterized in that, A filter layer and drainage holes are arranged at the position of the extremely low water level behind the front wall.

9. The implementation method of the diaphragm wall and pile foundation combined structure for strengthening a wharf according to any one of claims 1-8, characterized in that, Including the following steps: Excavate to form a working surface, and complete the construction of the front wall behind the existing wharf structure; at the same time, carry out the construction of the pile foundations; Integrally pour the breast wall and the cantilever beam; Backfill to form a wharf surface.

10. The implementation method of the diaphragm wall and pile foundation combined structure for strengthening a wharf according to claim 9, characterized in that, According to the front water depth, waves, geology and subsequent service loads, determine the setting of the anchor wall and tie rods by calculation, determine the parameters of the anchor wall and tie rods, and determine the connection method between the pile foundations and the cantilever beam; After the construction of the pile foundations is completed, construct a pile cap on the top of the pile foundations, and at the same time, carry out the construction of the anchor wall; Connect the anchor wall and the front wall with the tie rod, and connect the pile foundations and the cantilever beam; After integrally pouring the breast wall and the cantilever beam, tension the tie rod after the concrete strength reaches the design requirements.

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