Prestress bent cap construction method

Abstract

The invention discloses a prestressed bent cap construction method, which comprises the following steps of: erecting a bowl buckle type full framing on a foundation to form a supporting structure; the supporting mechanism is subjected to pre-pressing; a pouring formwork is erected through the supporting structure; concrete is poured into the pouring formwork to form a capping beam concrete body; and prestress tensioning is conducted on the cover beam concrete body, and grouting is conducted to form the prestress cover beam. The bowl buckle type full framing is erected on the foundation to form a stable supporting structure, the stability of the supporting structure is effectively improved, the requirement for complex foundation or large-span construction can be met, and the safety and efficiency of construction are remarkably improved; in addition, prestress tensioning and grouting are carried out on the cover beam concrete body, and the forming quality and the durability of long-term use of the cover beam structure are further ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of the construction of prestressed bent caps, and particularly relates to a construction method for prestressed bent caps. Background Art

[0002] A bent cap refers to a cross beam provided at the top of a row of pile piers to support, distribute, and transfer the loads of the upper structure, also known as a coping beam. A reinforced concrete or under-reinforced concrete cross beam is provided on a pier (abutment) or on a row of piles, and its main function is to support the upper structure of the bridge and transfer all the loads to the lower structure.

[0003] In the related art, in the traditional construction method of bent caps, temporary wooden struts or metal brackets are usually used to support the casting formwork and the newly cast concrete.

[0004] However, when the traditional construction method of bent caps faces construction projects under complex foundation conditions or when a large span needs to be achieved, it lacks a stable support structure. The bent cap structure formed by the traditional construction method of bent caps is prone to quality problems due to improper support, such as uneven casting, air bubbles, or cracks, resulting in low structural strength and poor durability of the bent cap. Summary of the Invention

[0005] The main purpose of the present invention is to provide a construction method for prestressed bent caps, aiming to improve the structural strength of the bent cap.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The present invention provides a construction method for prestressed bent caps, and the method includes:

[0008] Erect a waffle full hall support on the foundation to form a support structure;

[0009] Preload the support mechanism;

[0010] Use the support structure to erect a casting formwork;

[0011] Pour concrete into the casting formwork to form a bent cap concrete body;

[0012] Perform prestress tensioning on the bent cap concrete body and grout to form the prestressed bent cap.

[0013] In some embodiments, in the above construction method for prestressed bent caps, the step of erecting a waffle full hall support on the foundation to form a support structure includes:

[0014] Construct a pier body on the foundation and embed climbing cones in the pier body;

[0015] Connect a bracket and a beam bracket using the climbing cones;

[0016] Lay a plurality of first I-beams on the bracket to form a first installation layer;

[0017] Lay a single-row and single-layer reinforced Bailey beam on the first installation layer to form a second installation layer;

[0018] Lay a plurality of second I-beams on the second installation layer to form a third installation layer;

[0019] Lay the bowl-coupled full hall formwork on the third installation layer to form the support structure.

[0020] In some embodiments, in the above prestressed capping beam construction method, the plurality of first I-beams are spaced apart horizontally, the plurality of second I-beams are spaced apart horizontally, and the spacing between two adjacent first I-beams is equal to the spacing between two adjacent second I-beams.

[0021] In some embodiments, in the above prestressed capping beam construction method, the step of using the support structure to erect the casting formwork includes:

[0022] Erect the steel bar framework of the capping beam by using the support structure, and arrange corrugated pipes in the steel bar framework;

[0023] Erect the casting formwork along the contour of the steel bar framework;

[0024] The step of pouring concrete into the casting formwork to form a capping beam concrete body includes:

[0025] Pour concrete into the casting formwork to form a capping beam concrete body with the prestressed duct.

[0026] In some embodiments, in the above prestressed capping beam construction method, the step of prestress tensioning the capping beam concrete body and grouting to form the prestressed capping beam includes:

[0027] Judge whether the concrete strength of the capping beam concrete body meets the preset strength;

[0028] If so, perform prestress tensioning on the capping beam concrete body to form a capping beam to be grouted;

[0029] Use a vacuum grouting system to perform vacuum grouting on the prestressed duct to form the prestressed capping beam.

[0030] In some embodiments, in the above prestressed capping beam construction method, the step of using a vacuum grouting system to perform vacuum grouting on the prestressed duct to form the prestressed capping beam includes:

[0031] Use a vacuum pump to extract the air in the prestressed duct from one end of the prestressed duct;

[0032] Obtain the current vacuum degree inside the prestressed duct;

[0033] Judge whether the current vacuum degree meets the preset vacuum degree;

[0034] If so, connect the grouting pump to the other end of the prestressed duct;

[0035] Use the grouting pump to pour cement slurry into the prestressed duct until the prestressed duct is filled with the cement slurry.

[0036] In some embodiments, in the above prestressed capping beam construction method, the preset vacuum degree is A, and -0.06 MPa ≤ A ≤ -0.01 Mpa.

[0037] In some embodiments, in the above prestressed capping beam construction method, before the step of using the grouting pump to pour cement slurry into the prestressed duct until the prestressed duct is filled with the cement slurry, the prestressed capping beam construction method further includes:

[0038] Obtain the current slurry temperature of the cement slurry;

[0039] Judge whether the current slurry temperature meets the preset temperature;

[0040] If so, use the grouting pump to pour the cement slurry into the prestressed duct until the prestressed duct is filled with the cement slurry.

[0041] In some embodiments, in the above prestressed capping beam construction method, the preset temperature is T, and 5°C ≤ T ≤ 35°C.

[0042] In some embodiments, in the above prestressed capping beam construction method, before the step of erecting a bowl-coupled full hall support on the foundation to form a support structure, the method further includes:

[0043] Form a pouring groove in the geological body and pour concrete into the pouring groove to form a base;

[0044] Embed a plurality of anchor bolts in the base;

[0045] Install a plurality of steel supports on the base by using the plurality of anchor bolts;

[0046] Install a distribution beam on the steel support to form the foundation.

[0047] One or more of the above technical solutions provided by the present invention may have the following advantages or at least achieve the following technical effects:

[0048] A construction method for prestressed capping beams proposed by the present invention forms a stable support structure by erecting a full hall formwork support with bowl couplings on the foundation, effectively improving the stability of the support structure. It can not only meet the requirements of complex foundations or large-span construction, but also significantly improve the construction safety and efficiency. In addition, by prestressing and grouting the capping beam concrete body, the forming quality of the capping beam structure and the durability of long-term use are further ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these provided drawings.

[0050] Figure 1 It is a schematic flow chart of the construction method for prestressed capping beams in an embodiment of the present invention;

[0051] Figure 2 For Figure 1 It is a schematic detailed flow chart of step S10 in

[0052] Figure 3 For Figure 1 It is a schematic detailed flow chart of step S50 in

[0053] Figure 4 It is a schematic structural diagram of the vacuum grouting system involved in an embodiment of the present invention.

[0054] Explanation of the reference numerals in the drawings:

[0055] Label Name Label Name 100 Cement slurry mixer 200 Grouting pump 300 Prestressed bent cap 400 Slurry storage tank 500 Vacuum pump 210 First ball valve 310 Second ball valve 410 First valve 420 Second valve

[0056] The realization of the purpose of the present invention, functional features and advantages will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] To make the purpose, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0058] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back...) are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will change accordingly.

[0059] In the present invention, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or system. Without further limitation, the elements defined by the statement "including..." do not exclude the existence of additional identical elements in the process, method, article or system including such element. In addition, the meaning of "and / or" appearing throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where A and B are satisfied simultaneously.

[0060] In the present invention, unless otherwise clearly specified and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the communication inside two elements or the interaction relationship between two elements.

[0061] In the present invention, if there are descriptions involving "first", "second", etc., such descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one such feature.

[0062] In the present invention, the suffixes used to represent elements such as "module", "component", "part", "member" or "unit" are only for the convenience of explaining the present invention and have no specific meaning in themselves. Therefore, "module", "member" or "unit" can be used interchangeably.

[0063] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical solutions of each embodiment can be combined with each other, provided that it is based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0064] The inventive concept of the present invention will be further elaborated below in conjunction with some specific embodiments.

[0065] The present invention provides a construction method for a prestressed capping beam.

[0066] Referring to Figure 1 , the construction method for the prestressed capping beam includes:

[0067] Step S10: Erect a full hall formwork support with bowl fasteners on the foundation to form a support structure;

[0068] Step S20: Preload the support mechanism;

[0069] Step S30: Erect a casting formwork using the support structure;

[0070] Step S40: Pour concrete into the casting formwork to form a capping beam concrete body;

[0071] Step S50: Perform prestress tensioning on the capping beam concrete body and grout to form the prestressed capping beam 300.

[0072] During implementation, prestress tensioning can only be carried out after the concrete strength of the capping beam concrete body reaches 90% of its final setting concrete strength, and symmetric tensioning is carried out simultaneously at both ends in the order of steel strands. The "double control" method is adopted, with symmetric tensioning of the elongation and tensile force, using standard low-relaxation steel strands, and the tensioning control procedure is 0 → initial stress (0.1σcon) → 20%σcon → 100%σcon (holding for 2 minutes) → anchoring. Where σcon is the control stress during tensioning (including prestress losses), when tensioning simultaneously at both ends, the operations of the jacks at both ends for pressure increase and decrease, line marking, elongation measurement, pad insertion, etc. are consistent. After the tensioning construction is completed, the exposed steel strands are cut off (the exposed amount of the steel strands should not be less than 30 mm), and the anchor is sealed. The anchor is sealed with non-shrinking cement mortar. When sealing the anchor, the anchor plate and wedge jaws under the anchor and the exposed steel strands must be completely wrapped, and the thickness of the covering layer is greater than 15 mm. Grouting is carried out within 24 to 48 hours after sealing the anchor. After completing the grouting, end sealing construction is carried out to form the prestressed capping beam.

[0073] It should be noted that the maximum cross-sectional dimensions of the prestressed capping beam formed by using this construction method for the prestressed capping beam are 20.5 m × 3.16 m × 2.2 m. The full hall formwork support with bowl fasteners adopts a steel pipe Bailey beam support, the foundation is a steel pipe column foundation formed by C25 reinforced concrete, and the size of the foundation is 13 m × 1.5 m × 1 m; a Ф609 mm × 16 mm steel support is installed on the upper part, a 40a double-rolled I-beam is arranged on the steel support, a single-row and single-layer strengthened Bailey beam is arranged on the I-beam, and a 16 I-beam is arranged on the Bailey beam at a spacing of 60 cm. A full hall formwork support with bowl fasteners is erected on the I-beam, with a spacing of 60 cm × 60 cm and a cross-bar spacing of 120 cm.

[0074] It should be understood that the bowl-hook full-span bracket has high strength and good stability, can withstand greater loads, reduce the risk of displacement and collapse during construction, and can adapt to the needs of complex foundations and large spans, thereby directly solving the problem of insufficient stability of the supporting structure in traditional methods. The prestressed cap beam construction method adopts a bowl-hook full-span bracket, which allows operators to build and dismantle the supporting structure faster, reduces the need for additional adjustment and reinforcement of the supporting structure, makes the construction process more efficient, and thus improves the overall construction efficiency. Prestressing technology can pre-apply pressure by tensioning steel bars before pouring the concrete body, which helps to reduce cracks and defects in the concrete and improve the overall quality and durability of the structure. Combined with a stable bowl-hook support structure, it can ensure that the concrete is poured evenly during the construction process, further improving the quality and durability of the final structure of the prestressed cap beam. In addition, the stable support structure reduces the safety risks during the construction process, the bowl-hook full-span bracket is easy to operate, and reduces the danger of construction workers working at high altitudes. The application of prestressing technology also helps to reduce the quality problems of the cap beam structure during construction, thereby reducing safety hazards.

[0075] The technical solution of the present invention forms a stable supporting structure by setting up a bowl-hook type full-floor bracket on the foundation, which effectively improves the stability of the supporting structure. It can not only adapt to the needs of complex foundations or large-span construction, but also significantly improves the safety and efficiency of construction. In addition, by prestressing and grouting the cap beam concrete body, the molding quality and long-term durability of the cap beam structure are further ensured.

[0076] In one embodiment, continue to refer to Figure 1 And refer to Figure 2 The steps of setting up a bowl-hook type full-hall bracket on the foundation to form a supporting structure include:

[0077] Step S11, constructing a pier body on the foundation, and pre-embedding a climbing cone in the pier body;

[0078] Step S12, connecting the bracket and the beam support by using the climbing cone;

[0079] Step S13, setting up a plurality of first I-beams on the bracket to form a first installation layer;

[0080] Step S14, laying a single row and single layer of reinforced Bailey beams on the first installation layer to form a second installation layer;

[0081] Step S15, laying a plurality of second I-beams on the second installation layer to form a third installation layer;

[0082] Step S16: erecting the bowl-hook type full-hall bracket on the third installation layer to form the supporting structure.

[0083] During implementation, embed climbing cones during pier construction, connect the bracket with the bracket hanger seat, erect 36a I-beams on the bracket, erect a single-row and single-layer strengthened Bailey beam on the I-beams, and erect 16 I-beams on the Bailey beam with a spacing of 60 cm. Erect bowl-coupled scaffolds on the I-beams with a spacing of 60 cm × 60 cm and a cross-bar spacing of 120 cm.

[0084] It should be understood that by constructing the pier on the foundation and embedding climbing cones in step S11, a solid foundation can be provided for the entire support structure. The embedded climbing cones, as connection points, provide reliable fixing points for the subsequent installation of brackets and beam brackets, enhancing the stability and reliability of the entire support structure.

[0085] In step S12, by using climbing cones to connect the bracket and the beam bracket, the construction process of the support structure is simplified. The climbing cones provide a quick and reliable connection method, reducing the need for operators for complex fixing or adjustment, thus improving the construction efficiency.

[0086] In step S13, the construction of the first installation layer increases the bearing capacity and overall rigidity of the support structure by using I-beams, ensuring that during the construction process, the support system can evenly bear the weight of the capping beam and concrete, reducing quality problems caused by unstable support.

[0087] In step S14, the application of the strengthened Bailey beam further enhances the stability and bearing capacity of the entire support structure. By adding the second installation layer, the strength and stability of the entire support system are improved.

[0088] In step S15, by constructing the third installation layer, the stability and safety of the support structure are further improved. The layout of multiple layers of I-beams provides additional strength for the support system, ensuring stability during the construction process, thus reducing the safety risks during the construction process.

[0089] In step S16, the bowl-coupled full hall scaffold can adapt to different foundation conditions and span requirements, thus overcoming the limitations of traditional construction methods in dealing with complex engineering projects, and further improving the construction efficiency.

[0090] In an embodiment, multiple said first I-beams are spaced apart horizontally, multiple said second I-beams are spaced apart horizontally, and the spacing between adjacent two of said first I-beams is equal to the spacing between adjacent two of said second I-beams.

[0091] It should be noted that by flexibly adjusting the spacing between the first and second I-beams, complex projects with different spans and load requirements can be adapted, thereby improving the adaptability of this prestressed capping beam construction method to complex engineering conditions.

[0092] It should be understood that this prestressed cap beam construction method, through the evenly distributed first and second I-beams, can more effectively disperse and bear the upper construction load by the supporting structure, reduce the risk of local overload, ensure that the weight of concrete and other materials is evenly borne during construction, and reduce structural deformation or damage caused by uneven loads, thereby improving the stability of the entire prestressed cap beam structure and the quality and durability of the final structure.

[0093] In one embodiment, the step of using the support structure to set up a casting formwork includes:

[0094] Step S31, using the support structure to build a steel frame of the cap beam, and arranging a corrugated pipe in the steel frame;

[0095] Step S32, setting up the casting template along the outline of the steel frame;

[0096] The step of pouring concrete into the casting formwork to form a cap beam concrete body comprises:

[0097] Step S41, pouring concrete into the casting formwork to form a cap beam concrete body having the prestressed duct.

[0098] During implementation, a steel frame of the cap beam is built, and a corrugated pipe is arranged in the steel frame; the corrugated pipe is used to pass the steel strand during the tensioning construction of the cap beam, and multiple corrugated pipes are arranged in the same cap beam to form multiple prestressed channels. The casting template is set up along the outline of the steel frame, and the cap beam concrete body with prestressed channels is cast.

[0099] It should be understood that in step S31, the steel frame is the basis for ensuring the strength and durability of the cap beam structure. By arranging corrugated tubes in the steel frame, a channel can be provided for the subsequent tensioning of prestressed steel strands, which is crucial to improving the overall performance and durability of the structure. The application of corrugated tubes allows the cap beam to maintain its stability and strength through prestressed technology when subjected to long-term loads, thereby effectively solving the problems existing in traditional non-prestressed structures.

[0100] In step S32, the precise setting of the casting formwork directly affects the molding quality and appearance of the concrete. By setting up the formwork close to the contour of the steel frame, the shape accuracy and surface flatness during the concrete pouring process can be ensured, reducing the subsequent finishing workload and improving the overall quality and appearance of the structure.

[0101] Step S41 effectively improves the durability and bearing capacity of the cap beam by precisely controlling the concrete pouring process and ensuring the correct formation of prestressed ducts. The prestressed ducts allow subsequent application of prestress by tensioning steel strands, significantly enhancing the structure's deadweight and live load bearing capacity, further extending the service life of the cap beam.

[0102] In one embodiment, with continued reference to Figure 1 and with reference to Figure 3 , the steps of prestressing the bent cap concrete body and grouting to form the prestressed bent cap include:

[0103] Step S51: Determine whether the concrete strength of the bent cap concrete body meets the preset strength;

[0104] Step S52: If so, perform prestressing on the bent cap concrete body to form a bent cap to be grouted;

[0105] Step S53: Use a vacuum grouting system to perform vacuum grouting on the prestressed duct to form the prestressed bent cap 300.

[0106] During implementation, determine whether the concrete strength of the bent cap concrete body meets the preset strength; if so, perform prestressing on the bent cap concrete body to form a bent cap to be grouted; after tensioning the bent cap using each prestressed duct, cut off the steel strands exposed from the prestressed duct (the exposed amount of the steel strands should not be less than 30 mm), and perform anchor sealing. Anchor sealing is performed using non-shrinking cement mortar. When performing anchor sealing, the anchor plate and clamping pieces under the anchor and the exposed steel strands must be completely wrapped, and the thickness of the covering layer is greater than 15 mm. Grouting is performed within 24 to 48 hours after anchor sealing, and the grouting holes on the anchor plate under the anchor are cleaned to ensure the smoothness of the grouting channel. Use a vacuum grouting system to perform vacuum grouting on the prestressed duct to form the prestressed bent cap 300; use the vacuum grouting system to perform vacuum grouting on each prestressed duct one by one.

[0107] It should be noted that with reference to Figure 4 , the vacuum grouting system includes a cement slurry mixer 100, a grouting pump 200, a prestressed bent cap 300, a slurry storage tank 400, and a vacuum pump 500. The feed end of the grouting pump 200 is connected to the discharge end of the cement slurry mixer 100; a prestressed duct is formed in the prestressed bent cap 300, and one end of the prestressed duct is connected to the discharge end of the grouting pump 200 through a first ball valve 210; the feed end of the slurry storage tank 400 is connected to the other end of the prestressed duct through a second ball valve 310. The slurry storage tank 400 includes a first discharge end and a second discharge end, and the first discharge end is connected to a first valve 410; the feed end of the vacuum pump 500 is connected to the second discharge end of the slurry storage tank 400 through a second valve 420.

[0108] It can be understood that the cement slurry mixer 100 is used to mix cement slurry; the grouting pump 200 includes a slurry suction pipe, and the grouting pump 200 is used to suck the cement slurry mixed by the cement slurry mixer 100 into the pump body through the slurry suction pipe and press the cement slurry into the prestressed duct; when the grouting pump 200 continuously grouts the cement slurry into the prestressed duct in the prestressed capping beam 300, the slurry storage tank 400 is used to store the cement slurry overflowing from the prestressed duct, that is, the redundant cement slurry; the vacuum pump 500 is used to extract the air in the prestressed duct to make the prestressed duct in a vacuum state.

[0109] During implementation, the grouting end, i.e., the output end, of the grouting pump 200 is connected to one end of a prestressed duct, and a first ball valve 210 is arranged at the grouting end of the grouting pump 200. The first ball valve 210 is used to block or connect the grouting end of the grouting pump 200 and the prestressed duct communicated therewith. At the other end of the prestressed duct, the prestressed duct is connected to the slurry storage tank 400 by a pipeline. Moreover, a second ball valve 310 is arranged on the pipeline connecting the slurry storage tank 400 and the prestressed duct. The second ball valve 310 is used to block or connect the feeding end of the slurry storage tank 400 and the prestressed duct communicated therewith. Two discharging ends, i.e., a first discharging end and a second discharging end, are arranged on the slurry storage tank 400. A first valve 410 is arranged on the pipeline communicated with the first discharging end, a second valve 420 is arranged on the pipeline communicated with the second discharging end, the pipeline communicated with the second discharging end is used to connect the second discharging end with the feeding end of the vacuum pump 500, the first valve 410 is used to discharge the slurry or air in the storage tank to the end not communicated with the vacuum pump 500, and the second valve 420 is used to block or connect the second discharging end of the storage tank and the vacuum pump 500 communicated therewith.

[0110] When vacuum grouting the prestressed duct, first, close the first ball valve 210 and the first valve 410, open the second ball valve 310 and the second valve 420, and start the vacuum pump 500 to evacuate the prestressed duct.

[0111] After the vacuum degree of the prestressed duct meets the requirements, open the first ball valve 210, and start the grouting pump 200 to pump out the cement slurry mixed in the cement slurry mixer 100 and grout it into the prestressed duct. During this process, the vacuum pump 500 continuously evacuates the prestressed duct to prevent the air in the cement slurry from affecting the filling saturation of the cement slurry in the prestressed duct again. After the cement slurry in the prestressed duct is saturated, close the first ball valve 210, and then close the second ball valve 310 after a certain period of time to make the prestressed duct filled with the saturated cement slurry.

[0112] In this embodiment, the air in the prestressed duct is extracted by using the vacuum pump 500, and the prestressed duct is grouted by using the grouting pump 200 while the vacuum pump 500 is continuously turned on. While extracting the air in the upper arch curve of the cap beam, it further ensures that the prestressed duct is fully filled with cement slurry, thereby ensuring the actual load capacity of the cap beam and improving the construction quality of the cap beam.

[0113] In one embodiment, in modern bridge construction, the prestressed cap beam is an important structural element that undertakes the key task of transmitting and distributing the upper structure load while ensuring the stability and safety of the overall structure. The quality and performance of the prestressed cap beam directly affect the bearing capacity and durability of the bridge.

[0114] However, a major technical problem during the construction process is the presence of air in the duct, which will result in the duct not being fully grouted during the grouting process, thus affecting the prestressing effect and the overall quality of the cap beam. The existence of this problem not only reduces the actual load capacity of the cap beam, but also reduces the safety and reliability of the overall structure.

[0115] The step of performing vacuum grouting on the prestressed duct by using a vacuum grouting system to form the prestressed cap beam comprises:

[0116] Step S531, extracting air in the prestressed channel from one end of the prestressed channel using a vacuum pump;

[0117] Step S532, obtaining the current vacuum degree in the prestressed duct;

[0118] Step S533, determining whether the current vacuum degree meets the preset vacuum degree;

[0119] Step S534: If yes, connect the grouting pump 200 to the other end of the prestressed channel;

[0120] Step S535: Use the grouting pump 200 to inject cement slurry into the prestressed channel until the cement slurry fills the prestressed channel.

[0121] During implementation, while the grouting pump 200 is pouring cement slurry into the prestressed channel, the vacuum pump 500 is continuously turned on to apply positive pressure to the prestressed channel; the slurry condition of the cement slurry entering the vacuum pump 500 is obtained; it is determined whether the slurry condition meets the preset conditions; if so, the second ball valve 310 and the second valve 420 are used, and the grouting pump 200 is continued to be used to pour cement slurry into the prestressed channel.

[0122] In one embodiment, the positive pressure is F, 0.5 MPa≤F≤0.6 MPa.

[0123] During implementation, to ensure the grouting effect of vacuum grouting and the construction quality of the prestressed capping beam 300, the vacuum pump 500 keeps working continuously during the grouting process. When there is grout passing through the air filter at the end of the vacuum pump 500, close the valve (the second valve 420) at the front end of the air filter, and then open the exhaust valve. When the cement grout flows out smoothly from the exhaust valve and the consistency is the same as that of the grouted grout, close all the valves at the vacuum extraction end (the second ball valve 310 and the second valve 420). The grouting pump 200 continues to work until the pressure reaches 0.5 - 0.6 Mpa and holds the pressure for no less than 2 minutes.

[0124] Close the grouting pump 200 and all the valves at the grouting end (the first ball valve 210) to complete the grouting.

[0125] Dismantle the external pipelines and accessories, and clean the air filter and valves, etc., to carry out vacuum grouting for the next prestressed duct.

[0126] It should be noted that to enable the vacuum grouting system to have the condition of recycling and prevent the cement grout from clogging the pipelines and valves in the vacuum grouting system, after completing the grouting of the day, all the equipment with cement grout adhered to it must be cleaned thoroughly. The ball valves (the first ball valve 210) installed at the grouting end and the slurry outlet end should be removed and cleaned within one hour after grouting.

[0127] In an embodiment, to ensure that the cement grout in the prestressed duct can be fully filled and in a saturated state, the preset vacuum degree is A, -0.06 MPa ≤ A ≤ -0.01 Mpa.

[0128] It should be noted that by mass fraction, the cement grout includes the following components: 500 parts of water, 1389 parts of cement, and 138.9 parts of grouting agent; the cement is low-alkali ordinary Portland cement with a strength grade not lower than 42.5.

[0129] During implementation, to ensure that the water-cement ratio, fluidity, and bleeding of the cement grout meet the technical requirement indicators, so that the cement grout has a certain fluidity and will not quickly leave the prestressed duct due to the adsorption of the vacuum pump 500, resulting in the failure of vacuum grouting construction. The cement is low-alkali ordinary Portland cement with a strength grade not lower than 42.5, and a water-reducing agent and a rust inhibitor are added. The water-binder ratio does not exceed 0.34, there is no bleeding, the fluidity should be 14 - 22 s, and it should not be greater than 30 s after 30 minutes; the initial setting time is not less than 4 hours, and the final setting does not exceed 24 hours.

[0130] It should be understood that in the process of applying prestress, the injection of cement slurry is one of the key steps. The cement slurry needs to fully fill the pores to ensure that the protective layer around the steel strands is uniform and dense, thereby improving the durability and bearing capacity of the prestressed components. The uniformity and density of the cement slurry filling directly affect the performance of the prestressed components. Therefore, by setting a predetermined vacuum range (-0.06MPa to -0.01MPa), the full filling and density of the cement slurry in the pores can be promoted. The vacuum helps to extract the air in the pores, reduce the formation of bubbles, and form a more uniform and dense protective layer of the cement slurry in the pores. The loss of prestress and reduced durability caused by voids or unevenness inside the pores can be effectively avoided.

[0131] In one embodiment, before the step of using the grouting pump to inject cement slurry into the prestressed duct until the cement slurry fills the prestressed duct, the prestressed cap beam construction method further includes:

[0132] Step E10, obtaining the current slurry temperature of the cement slurry;

[0133] Step E20, determining whether the current slurry temperature meets a preset temperature;

[0134] Step E30: If yes, use the grouting pump 200 to inject the cement slurry into the prestressed channel until the cement slurry fills the prestressed channel.

[0135] It should be understood that the temperature of the cement slurry directly affects its fluidity, setting time and final strength. At a suitable temperature, the cement slurry can maintain good fluidity and be easy to pour, while ensuring that the setting and hardening process proceeds normally, thereby ensuring the quality and durability of the structure; inappropriate temperature will cause the cement slurry to solidify prematurely or have poor fluidity, affecting the grouting quality and structural performance. This embodiment can ensure that the slurry maintains suitable fluidity and later hardening quality during the pouring process by setting a suitable pouring temperature range for the cement slurry. Sufficient and uniform filling of the cement slurry is crucial to ensuring the effective binding of the prestressed steel strands and the durability of the entire structure. The use of the grouting pump 200 can accurately control the amount and speed of cement slurry injection to ensure that the cement slurry fully fills the prestressed pores and avoids the formation of voids or uneven density in the pores.

[0136] In one embodiment, the preset temperature is T, 5°C≤T≤35°C.

[0137] During implementation, the temperature of the cement paste during grouting shall not exceed 35°C and shall not be lower than 5°C, otherwise appropriate measures shall be taken to deal with it. The slurry has no corrosive effect on the steel strand.

[0138] It should be understood that the current temperature of the cement slurry is obtained to ensure that it is within a suitable temperature range, that is, 5°C to 35°C. This temperature range ensures that the cement slurry has good fluidity. It will not have poor fluidity due to too low a temperature, which makes it difficult to pour, nor will it solidify quickly due to too high a temperature, which affects the pouring effect and the subsequent coagulation process. This embodiment can ensure that the cement slurry maintains the best construction state during the grouting process by judging whether the actual temperature of the cement slurry is within a preset temperature range. If the temperature exceeds this range, measures need to be taken to adjust the temperature, such as heating or cooling the cement slurry, to avoid affecting the safety and durability of the structure. When it is confirmed that the cement slurry temperature meets the preset conditions, grouting using a grouting pump 200 can ensure that the cement slurry is poured into the prestressed pores at a suitable speed and pressure, thereby avoiding the generation of voids or unevenness. The suitable temperature range also helps the cement slurry to be evenly distributed in the pores, avoids inconsistent coagulation time caused by temperature differences, and ensures that a uniform and dense protective layer is formed around the prestressed steel strands.

[0139] In one embodiment, before the step of erecting a bowl-hook type full-height bracket on the foundation to form a supporting structure, the method further comprises:

[0140] Step P10, forming a casting trough in the geological body, and pouring concrete into the casting trough to form a base;

[0141] Step P20, pre-embedding a plurality of anchor bolts on the base;

[0142] Step P30, installing a plurality of steel supports on the base using a plurality of the anchor bolts;

[0143] Step P40: installing distribution beams on the steel supports to form the foundation.

[0144] It should be understood that step P10 can form a solid base by forming a casting trough on the geological body and pouring concrete, thereby solving the problem that a building or structure needs a stable foundation to bear various loads.

[0145] In step P20, the anchor bolts are embedded in the base to provide a reliable fixing point for the subsequent installation of steel supports or other supporting structures, ensuring that the superstructure can be firmly connected to the base during construction and use, thereby improving the overall stability and safety of the structure.

[0146] In step P30, the purpose of installing the steel support is to provide sufficient support force to ensure the stability of the superstructure when subjected to stress. The steel support is firmly fixed to the base by anchor bolts, which can effectively disperse and transfer the load of the superstructure and prevent the structure from displacement or collapse due to excessive load.

[0147] In step P40, the main purpose of installing the distribution beam is to evenly distribute the load from the upper structure to each steel support, which not only improves the overall stability and load-bearing capacity of the structure, but also ensures that the entire structure can still remain stable under uneven loads. The distribution beam ensures uniform stress on each part and avoids structural damage caused by local overload.

[0148] Finally, it should also be noted that the serial numbers of the above embodiments of the present invention are only for description and do not represent the superiority or inferiority of the embodiments. The above embodiments are only optional embodiments of the present invention and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or directly or indirectly applied to other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A method for constructing a prestressed cap beam, characterized in that: The method comprises: A bowl-shaped full-hall bracket is set up on the foundation to form a supporting structure; Pre-pressing the support mechanism; Using the support structure to set up a casting formwork; pouring concrete onto the casting template to form a cap beam concrete body; The cap beam concrete body is prestressed and grouting is performed to form the prestressed cap beam.

2. The prestressed cap beam construction method according to claim 1, characterized in that: The step of setting up a bowl-hook type full-hall bracket on the foundation to form a supporting structure comprises: Constructing a pier body on the foundation, and pre-embedding a climbing cone in the pier body; Connecting the bracket and the beam support by using the climbing cone; Placing a plurality of first I-beams on the bracket to form a first installation layer; A single row and single layer of reinforced Bailey beams are laid on the first installation layer to form a second installation layer; Laying down a plurality of second I-beams on the second installation layer to form a third installation layer; The bowl-hook type full-hall bracket is set up on the third installation layer to form the supporting structure.

3. The prestressed cap beam construction method according to claim 2, characterized in that: A plurality of the first I-beams are distributed at intervals in the horizontal direction, a plurality of the second I-beams are distributed at intervals in the horizontal direction, and a distance between two adjacent first I-beams is equal to a distance between two adjacent second I-beams.

4. The prestressed cap beam construction method according to claim 2, characterized in that: The step of using the support structure to set up a casting formwork comprises: The support structure is used to build a steel frame of the cap beam, and a corrugated pipe is arranged in the steel frame; Setting up the casting formwork along the outline of the steel bar frame; The step of pouring concrete into the casting formwork to form a cap beam concrete body comprises: Concrete is poured onto the casting formwork to form a cap beam concrete body having the prestressed duct.

5. The prestressed cap beam construction method according to claim 4, characterized in that: The steps of prestressing the cap beam concrete body and grouting to form the prestressed cap beam include: Determine whether the concrete strength of the cap beam concrete body meets the preset strength; If yes, prestressing is performed on the concrete body of the cap beam to form a cap beam to be grouted; The prestressed duct is vacuum grouted by using a vacuum grouting system to form the prestressed cap beam.

6. The prestressed cap beam construction method according to claim 5, characterized in that: The step of performing vacuum grouting on the prestressed duct by using a vacuum grouting system to form the prestressed cap beam comprises: Extracting air in the prestressed duct from one end of the prestressed duct using a vacuum pump; Obtaining the current vacuum degree in the prestressed duct; Determining whether the current vacuum degree meets a preset vacuum degree; If yes, connect the grouting pump to the other end of the prestressed channel; The grouting pump is used to inject cement slurry into the prestressed pores until the cement slurry fills the prestressed pores.

7. The prestressed cap beam construction method according to claim 6, characterized in that: The preset vacuum degree is A, -0.06MPa≤A≤-0.01Mpa.

8. The prestressed cap beam construction method according to claim 6, characterized in that: Before the step of using the grouting pump to inject cement slurry into the prestressed duct until the cement slurry fills the prestressed duct, the prestressed cap beam construction method further includes: Obtaining the current slurry temperature of the cement slurry; Determining whether the current slurry temperature meets a preset temperature; If so, the cement slurry is poured into the prestressed pores by using the grouting pump until the cement slurry fills the prestressed pores.

9. The prestressed cap beam construction method according to claim 8, characterized in that: The preset temperature is T, 5°C≤T≤35°C.

10. The prestressed cap beam construction method according to any one of claims 1 to 9, characterized in that: Before the step of erecting a bowl-hook type full-hall bracket on the foundation to form a supporting structure, the method further comprises: forming a casting trough in the geological body and pouring concrete into the casting trough to form a base; pre-embedding a plurality of anchor bolts on the base; installing a plurality of steel supports on the base using a plurality of the anchor bolts; A distribution beam is installed on the steel support to form the foundation.

Images