High-low bearing platform formwork reinforcing system and reinforcing method

Abstract

The invention relates to a high-low bearing platform template reinforcing system and a reinforcing method, and aims to solve the problems that the difference between the high elevation and the low elevation of a bearing platform in the same foundation pit is large, and construction joints and leakage are easy to generate in traditional mold hanging or segmented pouring, a pre-machined and formed special-shaped template continuously spans the high-position bearing platform and the low-position bearing platform, and a closed enclosing purlin without a horizontal construction joint is formed; the water stop split screws are arranged in the vertical direction according to the lateral pressure gradient in an encrypted mode, the screws are welded to the bearing platform steel bar framework, and a formwork-screw-steel bar overall stress chain is formed, so that the formwork system can be kept at the design position without external supporting in the one-time continuous concrete pouring process. According to the method, traditional formwork hoisting and secondary pouring are omitted, the formwork stability is remarkably improved, the hidden danger of leakage is eliminated, the construction period is shortened, and the construction cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of building construction, in particular to a high and low bearing platform formwork reinforcement system and a reinforcement method. Background Art

[0002] In today's construction industry, foundation types are mainly divided into strip foundations, independent foundations, raft foundations, box foundations, and pile foundations based on their construction methods. In the actual construction of various buildings, it is very common to have foundations of different heights.

[0003] After searching, CN209837675U proposed a pedestal formwork reinforcement device, which consists of a "J"-shaped pressure plate and tension screws. It is suitable for conventional equal-height pedestals, but does not solve the problem of suspended reinforcement of "high and low span" formwork.

[0004] CN201320254233.5 adopts channel steel purlin + water-stop screw for large-volume pedestals, but the system is bulky and requires a large operating surface to be reserved. It is not suitable for group pedestals with staggered heights and cramped spaces.

[0005] To address the significant height discrepancies between pile caps, the construction industry currently employs a segmented pouring method using suspended formwork. For example, in the foundation construction of large commercial buildings or high-rise residential buildings, significant height differences exist in pile cap designs due to building functionality. To accommodate these height differences, suspended formwork is used to divide the pile cap pouring area into multiple sections, which are then constructed sequentially.

[0006] However, this traditional construction method has significant drawbacks. Every additional construction joint creates a potential for leakage later in the construction process. Because the bond strength of the concrete at construction joints is relatively low, moisture and harmful substances from the underground soil can easily penetrate into the building through these weak spots. This not only affects the durability and safety of the building, but can also damage the indoor environment, increasing the cost and difficulty of future repairs. Summary of the Invention

[0007] The present invention aims to overcome the defects of the prior art and provide a high and low pedestal formwork reinforcement system and reinforcement method to solve the problem that concrete cannot be poured in one go due to the different elevations of the pedestals.

[0008] In order to solve the above-mentioned technical problems, the present invention is achieved as follows: A high-low bearing platform formwork reinforcing system, characterized in that: it comprises a special-shaped formwork, a water-stop tensioning screw rod and a bearing platform steel reinforcement cage; wherein the special-shaped formwork, after pre-processing, can continuously span the elevation difference of high and low bearing platforms and form a closed purlin without horizontal construction joints; the water-stop tensioning screw rod is arranged according to the vertical side pressure gradient, one end of which is anchored to the special-shaped formwork and the other end is welded to the bearing platform steel reinforcement cage, so as to directly transmit the concrete side pressure and buoyant force to the bearing platform steel reinforcement cage; the special-shaped formwork, the water-stop tensioning screw rod and the bearing platform steel reinforcement cage form an integral force chain through welding, so that the formwork system can maintain the designed position without external support during one-time continuous pouring, and the horizontal construction joint is eliminated.

[0009] The high-low bearing platform formwork reinforcing method, characterized by the following specific construction steps: a) After the completion of soil excavation and cushion construction, the steel reinforcement cages of the low bearing platform and the high bearing platform are bound; b) The formwork is pre-processed according to the high-low elevation difference of the bearing platform to form a special-shaped formwork that can continuously span the high-low elevation difference; c) The special-shaped formwork is supported outside the steel reinforcement cage to form a closed purlin together with the steel reinforcement cage; d) The water-stop tensioning screw rod is arranged according to the vertical side pressure gradient, wherein the distance between the first row of water-stop tensioning screw rods and the bottom surface of the low bearing platform is not more than 200 mm, and the distance between the remaining rows is 300-500 mm; e) One end of the water-stop tensioning screw rod is anchored to the special-shaped formwork and the other end is welded to the steel reinforcement cage to form an integral force chain; f) After the formwork system is accepted, the high-low span bearing platform concrete is poured continuously in one time; g) After the concrete reaches the designed strength, the special-shaped formwork and the water-stop tensioning screw rod are removed and recycled.

[0010] The high-low bearing platform formwork reinforcing method, characterized in that: the special-shaped formwork is assembled by connecting a plurality of standard formwork units through tongue and groove or bolts, and a continuous closed purlin is formed inside the assembled overall formwork.

[0011] The high-low bearing platform formwork reinforcing method, characterized in that: the middle part of the water-stop tensioning screw rod is provided with a ring-shaped water-stop piece, the outer diameter of which is not less than 2.5 times the outer diameter of the screw rod, and the water-stop piece and the screw rod are fully welded and sealed.

[0012] The high-low bearing platform formwork reinforcing method, characterized in that: the welding joint of the water-stop tensioning screw rod and the steel reinforcement cage adopts double fillet weld, the length of the welding joint is not less than 50 mm, and the height of the welding joint is not less than 0.3 times the diameter of the screw rod.

[0013] The high-low bearing platform formwork reinforcing method is characterized in that: the steel reinforcement framework is additionally provided with an additional reinforcing stirrup at a welding position of the water stop opposite-pulling screw rod, and the additional reinforcing stirrup is fixed by binding or welding with the main reinforcement, so as to improve the node bearing capacity.

[0014] The high-low bearing platform formwork reinforcing method is characterized in that: vertical back battens are arranged outside the special-shaped formwork, the back battens are made of steel pipes or wood bars, the interval of the back battens is not greater than 600 mm, and the back battens are connected with the water stop opposite-pulling screw rod through the gable card.

[0015] The high-low bearing platform formwork reinforcing method is characterized in that: a compressible sealing strip is arranged between the bottom of the special-shaped formwork and the cushion or the brick form membrane, so as to prevent concrete leakage during concrete pouring.

[0016] The high-low bearing platform formwork reinforcing method is characterized in that: the special-shaped formwork and the water stop opposite-pulling screw rod are integrally removed after the concrete reaches the design strength, and can be recycled for the next bearing platform construction.

[0017] The beneficial effects of the present application are: through the above technical solution, the present application provides a high-low bearing platform formwork reinforcing system and reinforcing method, the traditional high-low bearing platform construction adopts segmented pouring or hanging formwork, and it is necessary to leave a horizontal construction joint at the high-low junction and additionally provide a water stop steel plate or a grouting pipe. Since the other side of the bearing platform is close to the brick form membrane and the backfill soil, the water stop steel plate cannot be double-sided welded, and the grouting is also difficult to be full, and the leakage rate is generally more than 30% in the field statistics. The present application crosses the high-low elevation difference at one time through the special-shaped formwork, and the opposite-pulling screw rod with a water stop piece is arranged along the vertical direction, so that the concrete can be continuously poured at one time, and the horizontal construction joint is completely cancelled. Field measurement shows that after using the system, the bearing platform leakage rate is reduced to close to zero, and the post-leakage cost is saved by more than 90%. The water stop opposite-pulling screw rod and the bearing platform steel reinforcement are welded into an integral truss in the present application, forming a continuous force transmission path of “formwork → screw rod → steel reinforcement → bottom plate”, so that the lateral displacement of the formwork is reduced to <3mm from 10-15mm in the traditional method, and the vertical floating displacement is reduced to <2mm, completely meeting the allowable deviation of GB50204-2015; at the same time, the pit wall inclined support and a large number of floor supports are cancelled, the formwork system is more reliable in stress and more tidy in space.

[0018] The traditional method needs to go through eight processes of “supporting low-position formwork → pouring low-position concrete → curing → removing formwork → hoisting high-position formwork → supporting high-position formwork → secondary pouring → curing → secondary leakage blocking”, and at least 2.5 days are consumed for a single bearing platform. The present application compresses the eight processes into three steps of “one-time formwork supporting → one-time reinforcing → one-time pouring”, and the field measurement shows that the construction period is shortened to 1 day, and the comprehensive labor, machinery and turnover material cost is reduced by 30%-40%; the formwork and the water stop screw rod can be integrally hoisted, quickly removed and recycled, further improving the construction efficiency.

[0019] By eliminating waterstop steel plates, grouting pipes, and numerous supporting steel pipes, this system requires only conventional formwork, steel pipes, and waterstop screws. For example, for a typical pedestal with an 800mm height difference, conventional methods would require approximately 120m of Φ48×3.0mm supporting steel pipes and 8m of waterstop steel plates. This system, however, requires only 12 waterstop screws and 40m of steel pipe backing ribs, reducing steel usage by approximately 55%. On-site cutting and welding workloads are also reduced, significantly reducing noise, dust, and carbon emissions.

[0020] The present invention is applicable to pedestals with height differences of 200–1200 mm and variable plane dimensions. The formwork units can be assembled in the factory or on site, and the specifications of the water-stop screws are uniform, eliminating the need for additional customized large components. The invention can also be implemented in space-constrained scenarios such as the renovation of existing buildings, narrow foundation pits, and subway stations, and has broad prospects for engineering promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the structure of this application. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions of the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection requested by this application.

[0023] Example 1 like Figure 1 As shown: A high and low pedestal formwork reinforcement system includes special-shaped formwork, water-stop tension screws and pedestal steel frame; wherein, the special-shaped formwork can continuously span the elevation difference between the high and low pedestals after pre-processing and form a closed purlin without horizontal construction joints; the water-stop tension screws are arranged vertically according to the lateral pressure gradient, one end of which is anchored to the special-shaped formwork and the other end is welded to the pedestal steel frame, thereby directly transmitting the concrete lateral pressure and buoyancy force to the pedestal steel frame; the special-shaped formwork, water-stop tension screws and pedestal steel frame are welded to form an integral force chain, so that the formwork system can maintain the designed position without external support during the one-time continuous pouring process and eliminate horizontal construction joints.

[0024] A method for reinforcing high and low platform formwork, the specific construction steps are as follows: a) After the excavation and cushion construction are completed, tie the steel skeleton of the low and high caps; b) Pre-process the formwork according to the height difference of the pedestal to form a special-shaped formwork that can continuously span the height difference; c) Support the special-shaped formwork outside the steel frame so that it and the steel frame together form a closed perimeter purlin; d) The water-stop tie screws shall be arranged vertically according to the lateral pressure gradient. The distance between the first row of water-stop tie screws and the bottom surface of the low-level pedestal shall not exceed 200mm, and the spacing between the remaining rows shall be 300mm-500mm; e) Anchor one end of the waterstop tension screw to the special-shaped formwork, and weld the other end to the steel frame to form an integral force chain; f) After the formwork system has been accepted, pour the high and low span cap concrete continuously at one time; g) After the concrete reaches the designed strength, remove the special-shaped formwork and water-stop tension screws and reuse them.

[0025] The special-shaped template is assembled by connecting a number of standard template units through tongue and groove or bolts, and a continuous closed purlin is formed inside the assembled integral template.

[0026] An annular water stop plate is provided in the middle of the water stop tension screw rod, the outer diameter of the water stop plate is not less than 2.5 times the outer diameter of the screw rod, and the water stop plate and the screw rod are fully welded and sealed.

[0027] The welding node between the water-stop tension screw and the steel frame adopts double-sided fillet weld, the weld length is not less than 50mm, and the weld height is not less than 0.3 times the screw diameter.

[0028] The steel frame is provided with additional reinforcing stirrups at the welding point with the water-stop tension screw rod, and the additional reinforcing stirrups are tied or welded to the main reinforcement to improve the bearing capacity of the node.

[0029] A vertical back rib is provided on the outside of the special-shaped formwork. The back rib is made of steel pipe or wooden square. The spacing between the back ribs is not greater than 600 mm and is connected to the water-stop tension screw through a mountain-shaped clip.

[0030] A compressible sealing strip is provided between the bottom of the special-shaped formwork and the cushion layer or brick membrane to prevent leakage of concrete during pouring.

[0031] The special-shaped formwork and water-stop tension screws are removed as a whole after the concrete reaches the designed strength and can be used in the next foundation construction.

[0032] Example 2 A method for reinforcing high and low pedestal formwork, the main construction process and construction process technical requirements are as follows: Step 1: Foundation construction: After the earthwork construction is completed, the brick masonry and steel bar binding construction of the foundation will be carried out first; Step 2: Measure and lay out: After the reinforcement is tied, measure and lay out the formwork support area according to the thickness of the reinforcement cover; Step 3: template setting; according to the high-low elevation difference of the bearing platform, the template is processed in advance, and after the bearing platform and the bottom plate steel bar are bound, the configured template is set in the high-low span area of the bearing platform; Step 4: wear the pull screw; the first pull screw is arranged from the bottom to not more than 200mm, and the pull screw is uniformly arranged according to the high-low span height difference, and one pull screw and steel pipe are arranged every 300-500mm, and the schematic diagram is shown in the drawing; Step 5: template reinforcement; the pull screw and the bearing platform steel bar are welded and reinforced to ensure that the subsequent concrete is smoothly poured; Step 6: concrete pouring; when the concrete is poured, the stability of the template is detected.

[0033] The present application first proposes that the "one-time processing shaped template" directly crosses the high-low elevation difference, forms a self-sealing surrounding purlin, integrates the "high-low span" into a single shaped template, and cancels the secondary assembly and suspended support required by the traditional hanging template. The template changes from "separation" to "integration", which serves as a concrete forming surface and a force shell, reduces the construction level by one level, and improves the space utilization rate by more than 30%.

[0034] The water stop pull screw and the bearing platform steel skeleton are directly welded to form a continuous force transmission chain of "template->screw->steel->bottom plate", so that the steel skeleton becomes the "built-in support" of the template system. In the traditional method, the screw is only used as the template pull piece, and the steel bar is only used as the concrete reinforcement, and the two are independent in stress; the present application first combines the two into a composite truss, and the template no longer depends on the pit wall inclined support or external support system. Under the same concrete lateral pressure, the maximum displacement of the template is reduced from 12mm to <3mm (measured on site), and more than 60% of the inclined support steel pipe is saved.

[0035] The present application realizes the water stop function and the reinforcement function on the same component through the first vertical encryption arrangement method with a distance of ≤200mm from the bottom and the remaining 300-500mm equal interval, without additional water stop steel plate or grouting pipe, the construction joint length is reduced to zero, and the leakage probability is reduced from 35% to nearly zero.

[0036] The present application reinforces the template in the high-low span area of the bearing platform through the steel pipe, the pull screw and the template, and the traditional method generally leaves a construction joint. Since the other side of the bearing platform is a brick formwork and underground soil, the construction joint increases the risk of leakage in the later period, and the template reinforcement of the present application improves the one-time pouring of concrete.

[0037] The above are only examples provided by the present application and are not intended to limit the present application. Although the present application is described in detail with reference to the examples, those skilled in the art can modify the technical solutions described in the foregoing examples or make equivalent replacements to some of the technical features, but any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high and low platform formwork reinforcement system, characterized by: It includes special-shaped formwork, water-stop tension screws and pedestal steel frame; among them, the special-shaped formwork can continuously span the elevation difference between high and low pedestals after pre-processing and form a closed purlin without horizontal construction joints; the water-stop tension screws are arranged vertically according to the lateral pressure gradient, one end of which is anchored to the special-shaped formwork and the other end is welded to the pedestal steel frame, thereby directly transmitting the concrete side pressure and buoyancy force to the pedestal steel frame; the special-shaped formwork, water-stop tension screws and pedestal steel frame are welded to form an overall force chain, so that the formwork system can maintain the designed position without external support during the one-time continuous pouring process and eliminate horizontal construction joints.

2. A method for reinforcing high and low platform formwork according to claim 1, characterized in that The specific construction steps are as follows: a) After the excavation and cushion construction are completed, tie the steel skeleton of the low and high caps; b) Pre-process the formwork according to the height difference of the pedestal to form a special-shaped formwork that can continuously span the height difference; c) Support the special-shaped formwork outside the steel frame so that it and the steel frame together form a closed perimeter purlin; d) The water-stop tie screws shall be arranged vertically according to the lateral pressure gradient. The distance between the first row of water-stop tie screws and the bottom surface of the low-level pedestal shall not exceed 200mm, and the spacing between the remaining rows shall be 300mm-500mm; e) Anchor one end of the waterstop tension screw to the special-shaped formwork, and weld the other end to the steel frame to form an integral force chain; f) After the formwork system has been accepted, pour the high and low span cap concrete continuously at one time; g) After the concrete reaches the designed strength, remove the special-shaped formwork and water-stop tension screws and reuse them.

3. The method for reinforcing high and low platform formwork according to claim 2, characterized in that: The special-shaped template is assembled by connecting a number of standard template units through tongue and groove or bolts, and a continuous closed purlin is formed inside the assembled integral template.

4. The method for reinforcing a high and low platform formwork according to claim 2, characterized in that: An annular water stop plate is provided in the middle of the water stop tension screw rod, the outer diameter of the water stop plate is not less than 2.5 times the outer diameter of the screw rod, and the water stop plate and the screw rod are fully welded and sealed.

5. The method for reinforcing high and low platform formwork according to claim 2, characterized in that: The welding node between the water-stop tension screw and the steel frame adopts double-sided fillet weld, the weld length is not less than 50 mm, and the weld height is not less than 0.3 times the screw diameter.

6. The method for reinforcing high and low platform formwork according to claim 2, characterized in that: The steel frame is provided with additional reinforcing stirrups at the welding point with the water-stop tension screw rod, and the additional reinforcing stirrups are tied or welded to the main reinforcement to improve the bearing capacity of the node.

7. The method for reinforcing high and low platform formwork according to claim 2, characterized in that: A vertical back rib is provided on the outside of the special-shaped formwork. The back rib is made of steel pipe or wooden square. The spacing between the back ribs is not greater than 600 mm and is connected to the water-stop tension screw through a mountain-shaped clip.

8. The method for reinforcing high and low platform formwork according to claim 2, characterized in that: A compressible sealing strip is provided between the bottom of the special-shaped formwork and the cushion layer or brick membrane to prevent leakage of concrete during pouring.

9. The method for reinforcing high and low platform formwork according to claim 2, characterized in that: The special-shaped formwork and water-stop tension screws are removed as a whole after the concrete reaches the designed strength and can be used in the next foundation construction.

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