A formwork disassembly-free system for a basement foundation bottom plate post-pouring belt and a construction method thereof

Abstract

A formwork system and construction method for post-cast strips in basement foundation slabs that do not require removal includes upper and lower reinforcing bars and formwork that does not require removal. The formwork is installed along both sides of the post-cast strip, with its bottom supported by the top of the lower reinforcing bars and its top resting on the bottom of the upper reinforcing bars. The formwork includes a waterstop steel plate, upper and lower reinforcing bar skeletons, and upper and lower web concrete. One side of the waterstop steel plate is located in the base slab, and the other side is located in the post-cast strip. The upper end of the upper reinforcing bar skeleton is bent into hooks to connect with the upper reinforcing bars and has upper tie bars extending into the base slab concrete; the lower end of the lower reinforcing bar skeleton extends beyond the bottom of the lower web concrete and has lower tie bars extending into the base slab concrete. Post-cast concrete is poured between the two sides of the formwork that does not require removal, and a bottom seal is applied. This invention achieves formwork removal without removal, and through the waterstop steel plate, tie bars, and bottom seal, multiple waterstops are formed, ensuring reliable bonding between the old and new concrete, improving impermeability, shortening the construction period, and reducing costs.

Description

Technical Field

[0001] This invention belongs to the field of building engineering technology, specifically relating to a formwork system for post-pouring strips of basement foundation slabs that does not require removal and its construction method. Background Technology

[0002] In the construction of large basement foundation slabs, post-pouring strips are typically required to reduce the impact of concrete shrinkage cracks and temperature stress. Traditional post-pouring strip construction often uses wooden or steel formwork as temporary side forms. After the foundation slab concrete is poured and reaches a certain strength, the formwork is removed, and then the post-pouring strip concrete is poured. This traditional approach has the following drawbacks: 1) The post-pouring strip is in a narrow location, limiting the space for formwork installation and removal, making formwork erection and dismantling difficult, and easily damaging the edges of the foundation slab concrete during the removal process. 2) Traditional post-pouring strips usually have a water-stop steel plate in the middle of the foundation slab, but the gap between the formwork and the water-stop steel plate is difficult to completely seal, easily forming a seepage channel, resulting in unsatisfactory water-stopping effect. 3) After the formwork is removed, the sides of the foundation slab concrete are often too smooth or have release agent residue, leading to insufficient bonding between the post-pouring concrete and the previously poured foundation slab concrete, poor bonding between the old and new concrete, and a tendency to produce shrinkage cracks and leakage. 4) Although the upper and lower layers of reinforcing bars at the post-pouring strip are not disconnected, there is a lack of effective lateral support during concrete pouring, making the reinforcing bar cage prone to displacement and affecting the structural load-bearing performance. 5) The installation, removal and subsequent processing of the formwork are numerous and take up time. Furthermore, the post-pouring strip can only be cleaned and poured after the formwork is removed, resulting in a long construction period and affecting the overall construction progress.

[0003] Therefore, it is necessary to develop a post-cast strip formwork system that does not require demolition, provides reliable water stoppage, integrates well with both new and old concrete, and assists in the positioning of reinforcing bars. Summary of the Invention

[0004] The purpose of this invention is to provide a formwork system and construction method for post-cast strips of basement foundation slabs that does not require removal, in order to solve the technical problems of traditional formwork systems, such as difficulty in formwork erection, inconvenience in dismantling, poor water-stopping effect, easy cracking and leakage at the interface between new and old concrete, inaccurate positioning of reinforcing bars, and low construction efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] A formwork system for post-cast strips in basement foundation slabs that does not require removal includes upper and lower reinforcing bars, post-cast concrete, and foundation slab concrete poured on both sides of the post-cast strip. The upper and lower reinforcing bars are arranged within the foundation slab concrete and are not interrupted at the post-cast strip location. It also includes formwork that does not require removal; the formwork is arranged on both sides of the post-cast strip, with each side's formwork extending along the longitudinal axis of the post-cast strip. The bottom of the formwork is supported on the top of the lower reinforcing bars. The top of the slab rests on the bottom of the upper layer of reinforcing bars; the removable formwork includes a waterstop steel plate, an upper reinforcing bar cage, a lower reinforcing bar cage, upper web concrete, and lower web concrete; the waterstop steel plate is arranged along the longitudinal axis of the post-cast strip, with one side of the waterstop steel plate located in the bottom slab and the other side located in the post-cast strip; the upper and lower reinforcing bar cages are respectively arranged on the upper and lower sides of the waterstop steel plate, and both are arranged along the longitudinal axis of the waterstop steel plate; the lower part of the upper reinforcing bar cage extends towards the bottom slab concrete. One side of the upper reinforcing steel skeleton is bent, and upper hook bars are spaced apart on the side of the upper reinforcing steel skeleton facing the bottom slab concrete. The upper part of the lower reinforcing steel skeleton is bent towards the side of the bottom slab concrete, and lower hook bars are spaced apart on the side of the lower reinforcing steel skeleton facing the bottom slab concrete. The upper web concrete is poured outside the upper reinforcing steel skeleton along the long axis of the waterstop steel plate. The upper end of the upper reinforcing steel skeleton extends beyond the top of the upper web concrete, and the extended part is bent into a hook. The hook is connected to the upper reinforcing steel. The end of the upper hook bar extends beyond the upper web concrete, and the extended part extends into the bottom slab concrete on the corresponding side. The lower web concrete is poured outside the lower reinforcing steel skeleton along the long axis of the waterstop steel plate. The lower end of the lower reinforcing steel skeleton extends beyond the bottom of the lower web concrete. The end of the lower hook bar extends beyond the lower web concrete, and the extended part extends into the bottom slab concrete on the corresponding side. The post-cast concrete is poured between the two sides of the non-removable formwork, and bottom grouting is provided at the bottom joint between the post-cast concrete and the bottom slab concrete.

[0007] Preferably, a set of the non-removable templates is provided on each side of the post-pouring strip, and adjacent non-removable templates are connected by tongue and groove joints.

[0008] Preferably, the water-stop steel plate includes a flat plate segment; the flat plate segment is elongated, and the left and right sides of the flat plate segment are bent upwards to form a folded plate segment.

[0009] Preferably, the upper reinforcing steel skeleton includes upper longitudinal bars and upper connecting bars; there is one set of upper longitudinal bars, arranged at intervals along the vertical direction; there is one set of upper connecting bars, arranged at intervals along the longitudinal direction, and one set of upper connecting bars fixes and connects one set of upper longitudinal bars; the upper connecting bar consists of a first long vertical segment, a first folded segment, and a first short vertical segment; the first short vertical segment is welded to the top of the waterstop steel plate; the first folded segment is located at the top of the first short vertical segment, and the first folded segment gradually slopes towards the post-cast strip side from bottom to top; the first long vertical segment is located at the top of the first folded segment; the hook is formed by bending the upper end of the first long vertical segment; upper longitudinal bars are provided at the turning points of the first folded segment and the first long vertical segment, as well as at the turning points of the first folded segment and the first short vertical segment; the cross-sectional shape of the upper web concrete is adapted to the shape of the upper connecting bars.

[0010] Preferably, the lower reinforcing steel cage includes lower longitudinal bars and lower connecting bars; there is one set of lower longitudinal bars, arranged at intervals along the vertical direction; there is one set of lower connecting bars, arranged at intervals along the longitudinal direction, and one set of lower connecting bars fixes one set of lower longitudinal bars; the lower connecting bars consist of a second long vertical section, a second folded section, and a second short vertical section; the second short vertical section is welded to the bottom of the waterstop steel plate; the second folded section is located at the bottom of the second short vertical section, and the second folded section gradually slopes towards the post-cast strip side from top to bottom; the second long vertical section is located at the bottom of the second folded section, and the lower end of the second long vertical section extends into the bottom grout; lower longitudinal bars are provided at the turning points of the second folded section and the second long vertical section, as well as at the turning points of the second folded section and the second short vertical section; the cross-sectional shape of the lower web concrete is adapted to the shape of the lower connecting bars.

[0011] A construction method for a formwork-free system for post-cast strips in basement foundation slabs includes the following steps.

[0012] Step 1: Prefabricate the non-removable formwork. The non-removable formwork is prefabricated in the factory or on-site processing area, and specifically includes the following steps: Step 1.1: Take the waterstop steel plate and set it along the long axis of the post-cast strip. Bend the left and right sides of the waterstop steel plate upward to form a folded plate section. Step 1.2: Weld the upper steel reinforcement cage along the long axis of the waterstop steel plate on the upper side. The lower part of the upper steel reinforcement cage is bent towards the side closer to the bottom concrete slab, and upper tie bars are set at intervals on the side of the upper steel reinforcement cage facing the bottom concrete slab. Step 1.3: Weld the lower steel reinforcement cage along the long axis of the waterstop steel plate on the lower side of the waterstop steel plate. The upper part of the lower steel reinforcement cage is bent towards the side closer to the bottom concrete slab, and lower tie bars are set at intervals on the side of the lower steel reinforcement cage facing the bottom concrete slab. Step 1.4: Pour the upper web concrete on the upper side of the waterstop steel plate to wrap the upper steel reinforcement cage, so that the upper end of the upper steel reinforcement cage extends beyond the top of the upper web concrete, and bend the extended part into a hook; at the same time, make the end of the upper hook bar extend beyond the upper web concrete. Step 1.5: Pour the lower web concrete under the waterstop steel plate to wrap the lower steel reinforcement cage, so that the lower end of the lower steel reinforcement cage extends beyond the bottom of the lower web concrete, and at the same time, the end of the lower tie bar extends beyond the lower web concrete. Step 1.6: Cure to design strength to form a formwork that does not need to be removed; Step 2, on-site construction of upper and lower layer steel bars: Tie the lower and upper layer steel bars at the basement foundation slab. The lower and upper layer steel bars are not interrupted at the post-pouring strip, and the elevation of the top surface of the lower layer steel bars is controlled. Step 3, Install the formwork without removal: Hoist the prefabricated formwork without removal to both sides of the post-pouring strip, and set the formwork without removal on each side along the long axis of the post-pouring strip; The bottom of the formwork is supported on the top of the lower layer of reinforcing bars, and the top of the formwork is placed against the bottom of the upper layer of reinforcing bars. Connect the hooks at the top of the upper steel reinforcement cage to the upper layer of steel reinforcement; The lower end of the lower steel reinforcement cage is supported on the bottom slab cushion or the bottom grouting area; The protruding ends of the upper and lower tie bars should both point to the corresponding side of the bottom slab concrete area.

[0013] Step 4, pour the base slab concrete: pour the base slab concrete on both sides of the post-pouring strip, so that the protruding ends of the upper and lower tie bars are embedded in the base slab concrete on the corresponding sides, and at the same time, make one side of the waterstop steel plate located in the base slab concrete, and the other side exposed for the post-pouring strip to be poured. Step 5, pour post-concrete: Pour post-concrete between the two sides of the formwork that do not need to be removed, so that it can be combined with the exposed side of the waterstop steel plate, the upper web concrete and the lower web concrete to form a complete bottom plate structure. Step 6, Set bottom sealant: Set bottom sealant at the joint between the post-cast concrete and the bottom of the base slab concrete to seal the bottom gap.

[0014] Preferably, in step one, the upper and lower web concrete are formed using high-strength grouting material or C40 fine aggregate concrete. After forming, they are cured to reach the design strength. The surfaces of the upper and lower web concrete are roughened to increase surface friction and the bonding area of ​​the concrete.

[0015] Preferably, when a set of non-removable formwork is provided on each side of the post-pouring strip, adjacent non-removable formwork are connected by tongue and groove joints; in step one, tongue and groove joints are provided at the ends of the upper web concrete and the lower web concrete, and the segmented method is used to reduce the self-weight load, which facilitates transportation and installation. The use of tongue and groove joints can improve the overall integrity of the formwork after installation.

[0016] Preferably, in step three, the upper end of the upper steel reinforcement cage is bent to form a hook after the formwork is in place, and is firmly tied to the upper layer steel reinforcement of the nearby foundation slab. If there is no nearby upper layer steel reinforcement, upper auxiliary steel reinforcement is set on the upper layer steel reinforcement and firmly tied to the hook to avoid displacement of the upper part of the formwork caused by the impact of concrete pouring.

[0017] Preferably, in step three, the lower end of the lower steel reinforcement cage extends below the lower layer of steel reinforcement, and the lower auxiliary steel reinforcement is tied to the lower layer of steel reinforcement to fix the lower steel reinforcement cage, so as to avoid displacement of the lower part of the formwork due to the impact of concrete pouring.

[0018] Compared with the prior art, the present invention has the following features and beneficial effects.

[0019] 1. This invention achieves formwork removal without dismantling, greatly simplifying construction procedures and shortening the construction period. By setting up a formwork that does not need to be removed, the formwork is permanently placed on both sides of the post-pouring strip and does not need to be removed. This eliminates a series of cumbersome procedures such as formwork removal, side wall cleaning, roughening, and repair in traditional post-pouring strip construction, significantly simplifying the construction process and shortening the overall construction cycle.

[0020] 2. In this invention, the water-stop steel plate is installed along the entire length of the post-cast strip, and its left and right sides are bent upwards to form folded plate sections, effectively extending the seepage path of groundwater along the sides of the steel plate. One side of the water-stop steel plate is located in the bottom slab concrete, and the other side is located in the post-cast strip, forming the first water-stop barrier with the concrete on both sides. The upper and lower web concrete wraps around the reinforcing steel skeleton on the upper and lower sides of the water-stop steel plate, further sealing the microscopic gaps between the water-stop steel plate and the concrete. The bottom grouting at the bottom of the post-cast strip seals the bottom joint between the bottom slab and the post-cast strip. The above structures together constitute a multi-layered water-stop defense and a complete three-dimensional seepage prevention system, significantly improving the seepage resistance of the basement floor slab.

[0021] 3. In this invention, the ends of the upper and lower hook bars extend beyond the upper and lower web concrete, respectively, and into the corresponding bottom slab concrete, forming a mechanical anchorage. This effectively prevents cracking and leakage at the interface, enhancing the connection strength between the formwork and the pre-cast bottom slab concrete. Simultaneously, the surfaces of the upper and lower web concrete (preferably roughened) are in direct contact with the subsequent concrete, ensuring a reliable bond between the old and new concrete. This increases the bonding area and friction, avoiding the poor bonding problems caused by traditional smooth formwork surfaces. In summary, the above structure of this invention ensures a reliable, dense, and impermeable bond between the subsequent concrete, the bottom slab concrete, and the formwork.

[0022] 4. In this invention, the top of the formwork is connected to the upper layer of reinforcing bars via hooks, and the bottom is supported on top of the lower layer of reinforcing bars, forming a stable support system for the upper and lower layers of reinforcing bars. This effectively prevents displacement of the reinforcing bars during concrete pouring and ensures the structural performance. The lower end of the lower reinforcing bar skeleton extends beyond the bottom of the lower web concrete and into the bottom grouting area, further enhancing the stability of the lower part of the formwork. In a preferred embodiment, upper auxiliary reinforcing bars can be tied near the hooks, and lower auxiliary reinforcing bars can be tied on the lower layer of reinforcing bars to effectively resist the impact of concrete pouring and prevent displacement of the formwork.

[0023] 5. The modular prefabrication of the formwork without dismantling in this invention ensures controllable quality and convenient construction. It can be prefabricated in a factory or on-site processing area, using high-strength grouting material or C40 fine aggregate concrete. Curing conditions are controllable, resulting in stable quality. When the post-pouring strip is long, the formwork without dismantling can be prefabricated in sections (one set on each side), with tongue and groove connections between adjacent formwork sections. This reduces the self-weight of individual formwork sections, facilitating transportation and installation, while ensuring the integrity and tightness of the formwork after installation.

[0024] 6. The formwork of this invention does not need to be dismantled or discarded, which reduces the consumption of formwork materials and the generation of construction waste; at the same time, it simplifies the construction process, reduces labor, machinery shifts and post-processing costs, resulting in significant comprehensive economic benefits and meeting the requirements of green construction. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram of the structure in this invention where the upper and lower reinforcing steel skeletons are connected to the waterstop steel plate.

[0027] Figure 2 This is a schematic diagram of the non-removable template in this invention.

[0028] Figure 3 This is a schematic diagram of the template-free system in this invention.

[0029] Figure 4 This is a schematic diagram of the water-stopping steel plate in this invention.

[0030] Figure 5 This is a schematic diagram of the upper connecting rib in this invention.

[0031] Figure 6 This is a schematic diagram of the lower connecting rib in this invention.

[0032] Attached diagram notation: 1 – Upper reinforcement, 2 – Lower reinforcement, 3 – Post-cast concrete, 4 – Bottom slab concrete, 5 – Formwork not requiring removal, 5.1 – Waterstop steel plate, 5.1.1 – Flat plate section, 5.1.2 – Folded plate section, 5.2 – Upper reinforcement cage, 5.2.1 – Upper tie bar, 5.2.2 – Upper longitudinal reinforcement, 5.2.3 – Upper connecting bar, 5.2.3a – First long vertical section, 5.2.3b – First folded section, 5.2.3c - First short vertical section, 5.3 - Lower steel reinforcement cage, 5.3.1 - Lower tie bar, 5.3.2 - Lower longitudinal reinforcement, 5.3.3 - Lower connecting bar, 5.3.3a - Second long vertical section, 5.3.3b - Second folded section, 5.3.3c - Second short vertical section, 5.4 - Upper web concrete, 5.5 - Lower web concrete, 6 - Hook, 7 - Bottom grouting, 8 - Tongue and groove, 9 - Upper auxiliary reinforcement, 10 - Lower auxiliary reinforcement. Detailed Implementation

[0033] like Figure 1-6As shown, this formwork system for the post-cast strip of a basement foundation slab that does not require removal includes upper reinforcing bars 1, lower reinforcing bars 2, post-cast concrete 3, and foundation slab concrete 4 poured on both sides of the post-cast strip; the upper reinforcing bars 1 and lower reinforcing bars 2 are arranged in the foundation slab concrete 4, and neither the upper reinforcing bars 1 nor the lower reinforcing bars 2 are interrupted at the post-cast strip position; it also includes a formwork system that does not require removal 5; the formwork system that does not require removal 5 is arranged on both sides of the post-cast strip, and the formwork system that does not require removal 5 on each side is set along the longitudinal axis of the post-cast strip; the bottom of the formwork system that does not require removal 5 is supported on the top of the lower reinforcing bars 2, and the top of the formwork system that does not require removal 5 rests on the bottom of the upper reinforcing bars 1; The formwork 5 that does not require removal includes a water-stop steel plate 5.1, an upper reinforcing steel cage 5.2, a lower reinforcing steel cage 5.3, upper web concrete 5.4, and lower web concrete 5.5. The water-stop steel plate 5.1 is arranged along the longitudinal axis of the post-cast strip, with one side of the water-stop steel plate 5.1 located in the bottom slab and the other side of the water-stop steel plate 5.1 located in the post-cast strip. The upper reinforcing steel cage 5.2 and the lower reinforcing steel cage 5.3 are respectively arranged on the upper and lower sides of the water-stop steel plate 5.1, and both are arranged along the longitudinal axis of the water-stop steel plate 5.1. The lower part of the upper reinforcing steel cage 5.2 bends towards the side closer to the bottom slab concrete 4, and the upper steel... The reinforcing cage 5.2 has upper hook bars 5.2.1 spaced apart on the side facing the bottom slab concrete 4; the upper part of the lower reinforcing cage 5.3 bends towards the side closer to the bottom slab concrete 4, and lower hook bars 5.3.1 are spaced apart on the side of the lower reinforcing cage 5.3 facing the bottom slab concrete 4; the upper web concrete 5.4 is poured along the long axis of the waterstop steel plate 5.1 outside the upper reinforcing cage 5.2; the upper end of the upper reinforcing cage 5.2 extends beyond the top of the upper web concrete 5.4, and the extended part is bent into a hook 6; the hook 6 is hooked and connected to the upper reinforcing bar 1; the upper hook bars 5.2.1 are also provided. 2.1 The end of the upper web concrete 5.4 extends beyond the upper web concrete 5.4 and the extended part extends into the corresponding bottom slab concrete 4; the lower web concrete 5.5 is poured along the long axis of the waterstop steel plate 5.1 outside the lower reinforcement cage 5.3; the lower end of the lower reinforcement cage 5.3 extends beyond the bottom of the lower web concrete 5.5; the end of the lower tie bar 5.3.1 extends beyond the lower web concrete 5.5 and the extended part extends into the corresponding bottom slab concrete 4; the post-cast concrete 3 is poured between the two sides of the non-removable formwork 5, and a bottom seal 7 is provided at the bottom joint between the post-cast concrete 3 and the bottom slab concrete 4.

[0034] In this embodiment, a set of the non-removable template 5 is provided on each side of the post-pouring strip, and adjacent non-removable templates 5 are connected by tongue and groove joints.

[0035] In this embodiment, the water-stop steel plate 5.1 includes a flat plate segment 5.1.1; the flat plate segment 5.1.1 is elongated, and the left and right sides of the flat plate segment 5.1.1 are bent upwards to form a folded plate segment 5.1.2.

[0036] In this embodiment, the upper reinforcing steel skeleton 5.2 includes upper longitudinal bars 5.2.2 and upper connecting bars 5.2.3; there is one set of upper longitudinal bars 5.2.2, arranged at intervals along the vertical direction; there is one set of upper connecting bars 5.2.3, arranged at intervals along the longitudinal direction, and one set of upper connecting bars 5.2.3 fixes one set of upper longitudinal bars 5.2.2; the upper connecting bar 5.2.3 consists of a first long vertical segment 5.2.3a, a first bent segment 5.2.3b, and a first short vertical segment 5.2.3c; the first short vertical segment 5.2.3c is welded to the top of the waterstop steel plate 5.1; the first bent segment 5.2.2... 5.2.3b is located at the top of the first short vertical segment 5.2.3c, and the first folded segment 5.2.3b gradually slopes towards the post-cast strip side from bottom to top; the first long vertical segment 5.2.3a is located at the top of the first folded segment 5.2.3b; the hook 6 is formed by bending the upper end of the first long vertical segment 5.2.3a; the turning points of the first folded segment 5.2.3b and the first long vertical segment 5.2.3a, as well as the turning points of the first folded segment 5.2.3b and the first short vertical segment 5.2.3c, are all provided with upper longitudinal reinforcement 5.2.2; the cross-sectional shape of the upper web concrete 5.4 is adapted to the shape of the upper connecting reinforcement 5.2.3.

[0037] In this embodiment, the lower reinforcing steel skeleton 5.3 includes lower longitudinal bars 5.3.2 and lower connecting bars 5.3.3; there is one set of lower longitudinal bars 5.3.2, arranged at intervals along the vertical direction; there is one set of lower connecting bars 5.3.3, arranged at intervals along the longitudinal direction, and one set of lower connecting bars 5.3.3 fixes one set of lower longitudinal bars 5.3.2 together; the lower connecting bars 5.3.3 consist of a second long vertical segment 5.3.3a, a second bent segment 5.3.3b, and a second short vertical segment 5.3.3c; the second short vertical segment 5.3.3c is welded to the bottom of the waterstop steel plate 5.1; the second bent segment 5.3... 5.3b is located at the bottom of the second short vertical segment 5.3.3c, and the second folded segment 5.3.3b gradually slopes towards the post-cast strip side from top to bottom; the second long vertical segment 5.3.3a is located at the bottom of the second folded segment 5.3.3b, and the lower end of the second long vertical segment 5.3.3a extends into the bottom grouting 7; the turning points of the second folded segment 5.3.3b and the second long vertical segment 5.3.3a, as well as the turning points of the second folded segment 5.3.3b and the second short vertical segment 5.3.3c, are all provided with lower longitudinal reinforcement 5.3.2; the cross-sectional shape of the lower web concrete 5.5 is adapted to the shape of the lower connecting reinforcement 5.3.3.

[0038] The construction method for this formwork-free system for post-cast strips in basement foundation slabs includes the following steps.

[0039] Step 1: Prefabricate the non-removable formwork 5. The non-removable formwork 5 is prefabricated in the factory or on-site processing area, specifically including the following steps: Step 1.1: Take the waterstop steel plate 5.1 and set it along the long axis of the post-cast strip. Bend the left and right sides of the waterstop steel plate 5.1 upward to form the folded plate section 5.1.2. Step 1.2: Weld an upper steel reinforcement cage 5.2 along the long axis of the waterstop steel plate 5.1 on the upper side. The lower part of the upper steel reinforcement cage 5.2 is bent towards the side closer to the bottom concrete slab, and upper tie bars 5.2.1 are set at intervals on the side of the upper steel reinforcement cage 5.2 facing the bottom concrete slab 4. Step 1.3: Weld the lower steel reinforcement cage 5.3 along the long axis of the waterstop steel plate 5.1 on the lower side of the waterstop steel plate 5.1. The upper part of the lower steel reinforcement cage 5.3 is bent towards the side close to the bottom concrete 4, and lower tie bars 5.3.1 are set at intervals on the side of the lower steel reinforcement cage 5.3 facing the bottom concrete 4. Step 1.4: Pour the upper web concrete 5.4 on the upper side of the waterstop steel plate 5.1 to wrap the upper steel reinforcement cage 5.2, so that the upper end of the upper steel reinforcement cage 5.2 extends beyond the top of the upper web concrete 5.4, and bend the extended part into a hook 6; at the same time, make the end of the upper tie bar 5.2.1 extend beyond the upper web concrete 5.4. Step 1.5: Pour the lower web concrete 5.5 under the waterstop steel plate 5.1 to wrap the lower steel reinforcement cage 5.3, so that the lower end of the lower steel reinforcement cage 5.3 extends beyond the bottom of the lower web concrete 5.5, and at the same time, make the end of the lower tie bar 5.3.1 extend beyond the lower web concrete 5.5. Step 1.6: Cure to the design strength to form a formwork that does not need to be removed.

[0040] Step 2, on-site construction of upper layer steel bar 1 and lower layer steel bar 2: Tie the lower layer steel bar 2 and upper layer steel bar 1 at the basement foundation slab. The lower layer steel bar 2 and upper layer steel bar 1 are not broken at the post-pouring strip, and the elevation of the top surface of the lower layer steel bar 2 is controlled.

[0041] Step 3, Install the prefabricated formwork: Hoist the prefabricated formwork 5 to both sides of the post-pouring strip, with each side's formwork 5 running the entire length of the post-pouring strip; details are as follows: The bottom of the formwork 5 is supported on the top of the lower layer of steel bars 2, and the top of the formwork 5 is placed against the bottom of the upper layer of steel bars 1. Connect the hook 6 at the top of the upper steel reinforcement cage 5.2 to the upper steel reinforcement 1; Extend the lower end of the lower steel reinforcement cage 5.3 into the bottom grouting area; The overhanging ends of the upper hook bar 5.2.1 and the lower hook bar 5.3.1 should both point to the corresponding side of the bottom slab concrete area 4.

[0042] Step 4, pour the base slab concrete 4: Pour the base slab concrete 4 on both sides of the post-pouring strip, so that the protruding ends of the upper hook bar 5.2.1 and the lower hook bar 5.3.1 are embedded in the corresponding side of the base slab concrete 4, and at the same time, one side of the waterstop steel plate 5.1 is located in the base slab concrete 4, and the other side is exposed for the post-pouring strip to be poured.

[0043] Step 5, pour post-concrete 3: Pour post-concrete 3 between the two sides of the formwork 5 that can be removed, so that it can be combined with the exposed side of the waterstop steel plate 5.1, the upper web concrete 5.4 and the lower web concrete 5.5 to form a complete bottom plate structure.

[0044] Step 6, Set bottom sealant 7: Set bottom sealant 7 at the bottom joint between the post-cast concrete 3 and the bottom slab concrete 4 to seal the bottom gap.

[0045] In this embodiment, in step one, the upper web concrete 5.4 and the lower web concrete 5.5 are formed using high-strength grouting material or C40 fine aggregate concrete. After forming, they are cured to reach the design strength. The surfaces of the upper web concrete 5.4 and the lower web concrete 5.5 are roughened to improve surface friction and the bonding area of ​​the concrete.

[0046] In this embodiment, when a set of non-removable formwork 5 is provided on each side of the post-pouring strip, adjacent non-removable formwork 5 are connected by tongue and groove joints; in step one, tongue and groove joints 8 are provided at the ends of the upper web concrete 5.4 and the lower web concrete 5.5, and the segmented method is used to reduce the self-weight load, which is convenient for transportation and installation. The tongue and groove joints can improve the overall integrity of the formwork after installation.

[0047] In this embodiment, in step three, the upper end of the upper steel reinforcement skeleton 5.2 is bent to form a hook 6 after the formwork is in place, and is firmly tied to the upper steel reinforcement 1 of the nearby foundation slab. If there is no nearby upper steel reinforcement 1 near the hook 6, an upper auxiliary steel reinforcement 9 is set on the upper steel reinforcement 1 and firmly tied to the hook 6 to avoid displacement of the upper part of the formwork caused by the impact of concrete pouring.

[0048] In this embodiment, in step three, the lower end of the lower reinforcing steel skeleton 5.3 extends below the lower layer reinforcing steel 2, and the lower auxiliary reinforcing steel 10 is tied to the lower layer reinforcing steel 2 to fix the lower reinforcing steel skeleton 5.3, preventing displacement of the lower part of the formwork due to the impact of concrete pouring. Quick-drying high-strength mortar is used to seal the bottom of the foundation slab with grout 7. The bottom grout 7 formed by the lower end of the lower connecting bar 5.3.3 and the quick-drying high-strength mortar is similar to that of a reinforced concrete structure, possessing both compressive and tensile strength, effectively preventing grout leakage from the bottom of the foundation slab concrete.

[0049] In this embodiment, the water-stop steel plate 1 is made by bending both sides of a galvanized flat steel plate, with a bending angle of 45°.

[0050] In this embodiment, the upper connecting bars 5.2.3 and the lower connecting bars 5.3.3 are arranged in a one-to-one correspondence on the upper and lower sides of the water stop steel plate 5.1. The upper hook bars 6 are welded to the upper connecting bars 5.2.3; the lower hook bars 6 are welded to the lower connecting bars 5.3.3.

[0051] In this embodiment, the upper web concrete 5.4 and the lower web concrete 5.5 are formed by using high-strength grouting material or C40 fine aggregate concrete. After forming, they are cured to reach the design strength. The surfaces of the upper web concrete 5.4 and the lower web concrete 5.5 are roughened. The overall shape is designed like a "ji" character, which improves the surface friction and the bonding area of the concrete. The cross-sectional shapes of the upper web concrete 5.4 and the lower web concrete 5.5 both adopt two vertical segments at the upper and lower parts and an inclined segment in the middle. This design improves the bonding area between the post-cast strip formwork 5 that does not need to be disassembled and the bottom slab concrete 4, and improves the ability to cope with deformation and bending under the stress of the bottom slab concrete 4; attention should be paid to rust prevention and finished product protection of the upper connecting bars 5.2.3, the lower connecting bars 5.3.3, the upper hook bars 5.2.1, and the lower hook bars 5.3.1 during factory production, transportation and stacking. The upper hook bars 5.2.1 and the lower hook bars 5.3.1 increase the bond strength with the bottom slab concrete, bear shear force and part of the tensile stress, and are used for laterally connecting the bottom slab concrete to prevent dislocation between plates.

[0052] The above embodiments are not an exhaustive list of specific implementation manners, and there may be other embodiments. The above embodiments are intended to illustrate the present invention rather than limit the protection scope of the present invention. All applications obtained by simple changes of the present invention fall within the protection scope of the present invention.

Claims

1. A formwork system for post-cast strips in basement foundation slabs that does not require removal, comprising upper reinforcing bars (1), lower reinforcing bars (2), post-cast concrete (3), and foundation slab concrete (4) poured on both sides of the post-cast strip; wherein the upper reinforcing bars (1) and lower reinforcing bars (2) are arranged in the foundation slab concrete (4), and neither the upper reinforcing bars (1) nor the lower reinforcing bars (2) are interrupted at the post-cast strip location; characterized in that: It also includes a non-removable formwork (5); the non-removable formwork (5) is arranged on both sides of the post-pouring strip, and the non-removable formwork (5) on each side is set along the long axis of the post-pouring strip; the bottom of the non-removable formwork (5) is supported on the top of the lower layer of reinforcing bars (2), and the top of the non-removable formwork (5) is against the bottom of the upper layer of reinforcing bars (1); the non-removable formwork (5) includes a waterstop steel plate (5.1), an upper reinforcing bar skeleton (5.2), a lower reinforcing bar skeleton (5.3), upper web concrete (5.4), and lower web concrete (5.5); the waterstop steel plate (5.1) is set along the long axis of the post-pouring strip, and the waterstop steel plate (5.2) is set along the long axis of the post-pouring strip, and the top of the non-removable formwork (5.3) is against the bottom of the upper layer of reinforcing bars (1); the non-removable formwork (5.1) includes a waterstop steel plate (5.1), an upper reinforcing bar skeleton (5.2), a lower reinforcing bar skeleton (5.3), an upper web concrete (5.4), and a lower web concrete (5.5); the waterstop steel plate (5.1) is set along the long axis of the post-pouring strip, and the waterstop steel plate (5.2) is set along the long axis of the post-pouring strip, and the top of the non-removable formwork (5.2) is against the bottom of the upper layer of reinforcing bars (1); the non-removable formwork (5.2) includes a waterstop steel plate (5.3), an upper reinforcing bar skeleton (5.4), and a lower web concrete (5.5); the waterstop steel plate (5.2) is set along the long axis of the post-pouring strip, and the top of the non-removable formwork (5.2) is .1) One side of the waterstop steel plate (5.1) is located in the bottom slab, and the other side of the waterstop steel plate (5.1) is located in the post-cast strip; the upper steel reinforcement cage (5.2) and the lower steel reinforcement cage (5.3) are respectively arranged on the upper and lower sides of the waterstop steel plate (5.1), and are both set along the long axis of the waterstop steel plate (5.1); the lower part of the upper steel reinforcement cage (5.2) bends towards the side close to the bottom slab concrete (4), and upper hook bars (5.2.1) are spaced apart on the side of the upper steel reinforcement cage (5.2) facing the bottom slab concrete (4); the upper part of the lower steel reinforcement cage (5.3) bends towards the side close to the bottom slab concrete (4) Laterally bent, lower hook bars (5.3.1) are provided at intervals on the side of the lower reinforcing cage (5.3) facing the bottom slab concrete (4); the upper web concrete (5.4) is poured along the long axis of the waterstop steel plate (5.1) outside the upper reinforcing cage (5.2); the upper end of the upper reinforcing cage (5.2) extends beyond the top of the upper web concrete (5.4), and the extended part is bent into a hook (6); the hook (6) is hooked to the upper reinforcing bar (1); the end of the upper hook bar (5.2.1) extends beyond the upper web concrete (5.4), and the extended part extends into the corresponding side. In the bottom slab concrete (4); the lower web concrete (5.5) is poured along the long axis of the waterstop steel plate (5.1) outside the lower reinforcement cage (5.3); the lower end of the lower reinforcement cage (5.3) extends beyond the bottom of the lower web concrete (5.5); the end of the lower tie bar (5.3.1) extends beyond the lower web concrete (5.5) and the extended part extends into the bottom slab concrete (4) on the corresponding side; the post-cast concrete (3) is poured between the two sides of the non-removable formwork (5), and a bottom seal grout (7) is provided at the bottom joint between the post-cast concrete (3) and the bottom slab concrete (4).

2. The formwork removal-free system for post-cast strips of basement foundation slabs as described in claim 1, characterized in that: The non-removable template (5) is provided on each side of the post-pouring strip, and the adjacent non-removable templates (5) are connected by tongue and groove.

3. The formwork removal-free system for post-pouring strips of basement foundation slabs as described in claim 1, characterized in that: The waterstop steel plate (5.1) includes a flat plate segment (5.1.1); the flat plate segment (5.1.1) is long and narrow, and the left and right sides of the flat plate segment (5.1.1) are bent upwards to form a folded plate segment (5.1.2).

4. The formwork removal-free system for post-pouring strips of basement foundation slabs as described in claim 1, characterized in that: The upper steel reinforcement cage (5.2) includes upper longitudinal bars (5.2.2) and upper connecting bars (5.2.3); there is one set of upper longitudinal bars (5.2.2), arranged at intervals along the vertical direction; there is one set of upper connecting bars (5.2.3), arranged at intervals along the longitudinal direction, and one set of upper connecting bars (5.2.3) fixes one set of upper longitudinal bars (5.2.2); the upper connecting bar (5.2.3) consists of a first long vertical segment (5.2.3a), a first bent segment (5.2.3b), and a first short vertical segment (5.2.3c); the first short vertical segment (5.2.3c) is welded to the top of the waterstop steel plate (5.1); the first bent segment (5.2.3b)... The first short vertical section (5.2.3c) is located at the top of the first short vertical section (5.2.3c), and the first folded section (5.2.3b) gradually slopes towards the post-cast strip from bottom to top; the first long vertical section (5.2.3a) is located at the top of the first folded section (5.2.3b); the hook (6) is formed by bending the upper end of the first long vertical section (5.2.3a); the first folded section (5.2.3b) and the first long vertical section (5.2.3a) are connected by upper longitudinal reinforcement (5.2.2) at the turning points of the first folded section (5.2.3b) and the first short vertical section (5.2.3c); the cross-sectional shape of the upper web concrete (5.4) is adapted to the shape of the upper connecting reinforcement (5.2.3).

5. The formwork removal-free system for post-pouring strips of basement foundation slabs as described in claim 1, characterized in that: The lower reinforcing steel cage (5.3) includes lower longitudinal bars (5.3.2) and lower connecting bars (5.3.3); there is one set of lower longitudinal bars (5.3.2), arranged at intervals along the vertical direction; there is one set of lower connecting bars (5.3.3), arranged at intervals along the longitudinal direction, and one set of lower connecting bars (5.3.3) fixes one set of lower longitudinal bars (5.3.2); the lower connecting bars (5.3.3) consist of a second long vertical segment (5.3.3a), a second bent segment (5.3.3b), and a second short vertical segment (5.3.3c); the second short vertical segment (5.3.3c) is welded to the bottom of the waterstop steel plate (5.1); the second bent segment (5.3.3b)... The second short vertical section (5.3.3c) is located at the bottom of the second short vertical section (5.3.3c), and the second folded section (5.3.3b) gradually slopes towards the post-cast strip from top to bottom; the second long vertical section (5.3.3a) is located at the bottom of the second folded section (5.3.3b), and the lower end of the second long vertical section (5.3.3a) extends into the bottom grout (7); the turning points of the second folded section (5.3.3b) and the second long vertical section (5.3.3a) and the turning points of the second folded section (5.3.3b) and the second short vertical section (5.3.3c) are all provided with lower longitudinal reinforcement (5.3.2); the cross-sectional shape of the lower web concrete (5.5) is adapted to the shape of the lower connecting reinforcement (5.3.3).

6. A construction method for a formwork-free system for post-cast strips of basement foundation slabs as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1, Prefabricate the non-removable formwork (5). The non-removable formwork (5) is prefabricated in the factory or on-site processing area, specifically including the following steps: Step 1.1, take the waterstop steel plate (5.1) and set it along the long axis of the post-pouring strip. Bend the left and right sides of the waterstop steel plate (5.1) upward to form a folded plate section (5.1.2). Step 1.2, weld the upper steel reinforcement cage (5.2) along the long axis of the waterstop steel plate (5.1) on the upper side. The lower part of the upper steel reinforcement cage (5.2) bends towards the side close to the bottom concrete slab, and upper hook bars (5.2.1) are set at intervals on the side of the upper steel reinforcement cage (5.2) facing the bottom concrete slab (4). Step 1.3, weld the lower steel reinforcement cage (5.3) along the long axis of the waterstop steel plate (5.1) on the lower side of the waterstop steel plate (5.1). The upper part of the lower steel reinforcement cage (5.3) bends towards the side close to the bottom slab concrete (4), and lower tie bars (5.3.1) are set at intervals on the side of the lower steel reinforcement cage (5.3) facing the bottom slab concrete (4). Step 1.4: Pour the upper web concrete (5.4) on the upper side of the waterstop steel plate (5.1) to wrap the upper steel reinforcement cage (5.2), so that the upper end of the upper steel reinforcement cage (5.2) extends beyond the top of the upper web concrete (5.4), and bend the extended part into a hook (6); at the same time, make the end of the upper tie bar (5.2.1) extend beyond the upper web concrete (5.4). Step 1.5: Pour the lower web concrete (5.5) under the waterstop steel plate (5.1) to wrap the lower steel reinforcement cage (5.3), so that the lower end of the lower steel reinforcement cage (5.3) extends beyond the bottom of the lower web concrete (5.5), and at the same time, the end of the lower tie bar (5.3.1) extends beyond the lower web concrete (5.5). Step 1.6: Cure to design strength to form a formwork that does not need to be removed; Step 2, on-site construction of upper layer steel bars (1) and lower layer steel bars (2): tie the lower layer steel bars (2) and upper layer steel bars (1) at the basement foundation slab position. The lower layer steel bars (2) and upper layer steel bars (1) are not cut off at the post-pouring strip position, and the elevation of the top surface of the lower layer steel bars (2) is controlled. Step 3, Install the template without dismantling: hoist the prefabricated template (5) to both sides of the post-pouring strip, and set the template (5) on each side along the long axis of the post-pouring strip; Step 4, pour the bottom slab concrete (4): pour the bottom slab concrete (4) on both sides of the post-pouring strip, so that the overhanging ends of the upper hook bar (5.2.1) and the lower hook bar (5.3.1) are embedded in the bottom slab concrete (4) on the corresponding side, and at the same time, one side of the waterstop steel plate (5.1) is located in the bottom slab concrete (4), and the other side is exposed for the post-pouring strip to be poured. Step 5, pour post-cast concrete (3): pour post-cast concrete (3) between the two sides of the formwork (5) to combine it with the exposed side of the waterstop steel plate (5.1), the upper web concrete (5.4) and the lower web concrete (5.5) to form a complete bottom plate structure. Step 6, Set bottom seal (7): Set bottom seal (7) at the bottom joint between the post-cast concrete (3) and the bottom slab concrete (4) to seal the bottom gap.

7. The construction method of the formwork-free system for post-cast strips of basement foundation slabs according to claim 6, characterized in that: In step one, the upper web concrete (5.4) and the lower web concrete (5.5) are formed by high-strength grouting material or by C40 fine stone concrete. After forming, they are cured to reach the design strength. The surfaces of the upper web concrete (5.4) and the lower web concrete (5.5) are roughened to improve surface friction and the bonding area of ​​the concrete.

8. The construction method of the formwork-free system for post-cast strips of basement foundation slabs according to claim 6, characterized in that: When there is a set of non-removable formwork (5) on each side of the post-pouring strip, the adjacent non-removable formwork (5) are connected by tongue and groove; in step one, tongue and groove (8) are provided at the ends of the upper web concrete (5.4) and the lower web concrete (5.5).

9. The construction method of the formwork-free system for post-cast strips of basement foundation slabs according to claim 6, characterized in that: In step three, the upper end of the upper steel reinforcement skeleton (5.2) is bent to form a hook (6) after the formwork is in place, and is tied firmly to the upper steel reinforcement (1) of the nearby foundation slab. If there is no nearby upper steel reinforcement (1) near the hook (6), an upper auxiliary steel reinforcement (9) is set on the upper steel reinforcement (1) and tied firmly to the hook (6) to avoid displacement of the upper part of the formwork caused by the impact of concrete pouring.

10. The construction method of the formwork-free system for post-cast strips of basement foundation slabs according to claim 6, characterized in that: In step three, the lower end of the lower steel reinforcement cage (5.3) extends below the lower layer steel reinforcement (2), and the lower auxiliary steel reinforcement (10) is tied on the lower layer steel reinforcement (2) to fix the lower steel reinforcement cage (5.3) and prevent the lower part of the formwork from shifting due to the impact of concrete pouring.

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