Design and construction method for prefabricated shear wall without rib exposure

Abstract

The invention discloses a reinforcement-free prefabricated shear wall design and construction method which comprises the following steps: step 1, vertical connection design and construction, step 2, horizontal connection design and construction: after a prefabricated shear wall is hoisted in place, mounting a horizontal connection anchor bolt so as to avoid a reinforcement collision phenomenon during mounting; 3, designing and constructing the connection of the laminated slabs, wherein the connection of the laminated slabs comprises a design and construction method of the laminated slabs with the ribs exposed and a design and construction method of the laminated slabs without the ribs exposed; 4, designing and constructing side key grooves and front inclined struts of the prefabricated shear wall; according to the method, reinforcing steel bars do not come out of the six faces of the prefabricated wall, manufacturing is easy, standardization is high, construction precision is low, when a corrugated pipe of 60 mm is adopted, the fault-tolerant size is about 40 mm and is increased by 10 times compared with the prior art, and the fault-tolerant rate is high; the problem that the plumpness of the grouting sleeve cannot be detected is solved; bolt connection is adopted for horizontal connection, anchoring is reliable, and construction is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a design and construction method of a prefabricated shear wall without reinforcement. Background Art

[0002] At present, the method of prefabricated wall reinforcement is used. Prefabricated walls are like hedgehogs, with various and complex steel bar specifications and spacing, and mold processing is difficult, so they cannot be standardized and prefabricated; the vertical connection method is mostly grouting sleeves, which require high precision for components and construction, and the allowable error on site is 2 to 5 mm, resulting in poor quality assurance, low construction efficiency, and no effective means for quality inspection, and the fullness of the grouting cannot be determined; the horizontal connection uses extended steel bars anchored into the post-casting area, which leads to serious steel bar fights and collisions on site, and slow construction speed. In addition, the existing prefabricated shear walls are low in standardization, and the extended steel bars need to be protected during transportation, which is inefficient and the cost of grouting sleeves is high. At the current assembly site, steel bars fight, and on-site installation is difficult. At present, the shear wall adopts a rough surface method, and the end and the post-casting section are cast twice, which is completely separated, and the shear resistance has safety hazards. And there is no related overall method in the prior art. For example, the Chinese patent with publication number CN115288302A discloses a prefabricated shear wall and composite slab node, which is applied to the technical field of prefabricated buildings. It includes a shear wall perpendicular to the ground and a composite slab perpendicular to the shear wall. The top wall of the shear wall is penetrated with a number of positioning ribs in the vertical direction, and the bottom wall of the composite slab is penetrated with a number of positioning holes, and the positioning ribs are correspondingly arranged in the positioning holes; the bottom wall of the composite slab is penetrated with a mounting hole corresponding to the shear wall, and a reinforcing rib is penetrated in the mounting hole, and a clamping assembly is arranged in the mounting hole, and the outer side of the clamping assembly is supported on the side hole wall of the mounting hole, and the inner side of the clamping assembly is against the reinforcing rib. The top wall of the shear wall is provided with an alignment hole corresponding to the mounting hole, and the bottom end of the reinforcing rib extends into the corresponding alignment hole, and the side wall of the shear wall is provided with a grouting hole, and the grouting hole is connected to the alignment hole. The extended steel bars of the patent are anchored in the post-casting area, which leads to serious steel bar fights and collisions on site and slow construction speed. In addition, existing prefabricated shear walls have low standardization, require protection of protruding steel bars during transportation, have low efficiency, and high costs for grouting sleeves.

[0003] Therefore, a design and construction method of a prefabricated shear wall without reinforcement is provided to solve the above technical problems. Summary of the invention

[0004] The purpose of the present invention is to provide a design and construction method for prefabricated shear walls without reinforcement, which is the highlight of prefabricated buildings. The prefabrication of shear walls is standardized, with high transportation efficiency, simple installation, safe and reliable, high on-site fault tolerance, and the support can be reused. It is conducive to the promotion of prefabricated sandwich insulation exterior walls in public construction projects.

[0005] The object of the present invention is achieved in that:

[0006] A design and construction method for a prefabricated shear wall without reinforcement, comprising the following steps:

[0007] Step 1: Design and construct the vertical connection. With the help of corrugated pipe holes, additional connecting steel bars are used to realize the transformation of steel bars from two rows to one row. The details are as follows: Step 1.1: Design and determine the vertical connection length parameters. The basic anchor length L ab Determined by formula, take L ab =α·fy / ft·d, α value: 0.16 for round steel bar, 0.14 for ribbed steel bar, 0.13 for spiral ribbed steel bar, fy is the design value of steel bar tensile strength, ft is the design value of concrete axial compressive strength, d is the diameter of vertical steel bar; the influence of different anchorage lengths on the connection performance of the specimens, anchorage length L a Take different coefficients and multiply them by their basic anchorage length L ab , L a =k*L ab , k is the anchorage length coefficient selected in this test; Step 1.2, after the prefabricated wall reinforcement cage is in place, cut the length L of the corrugated pipe and insert it into the prefabricated wall reinforcement cage; L = L a ,L a The anchorage length is adjusted according to the concrete strength in the corrugated pipe;

[0008] Step 1.3: After the prefabricated wall is installed and positioned, the connecting steel bars are inserted into the corrugated tube, and concrete is poured into the corrugated tube; Step 1.4: The ring beam steel bars are installed;

[0009] Step 1.5: After the ring beam reinforcement is installed, hoist the composite slab;

[0010] Step 1.6, pouring the post-casting section concrete;

[0011] Step 1.7, hoist the upper prefabricated wall;

[0012] Step 1.8, pouring concrete inside the corrugated pipe;

[0013] Step 2: Design and construct the horizontal connection. After the prefabricated shear wall is hoisted in place, install the horizontal connection anchor bolts to avoid steel bar collision during installation.

[0014] Step 3: Design and construction of composite slab connection, which includes the design and construction method of composite slab with reinforcement and the design and construction method of composite slab without reinforcement;

[0015] Step 4: Design and construction method of the side keyway and front diagonal brace of the prefabricated shear wall;

[0016] Step 5: Design and construction of temporary support anchor bolts.

[0017] The specific operation of step 2 is as follows: Step 2.1, wall production: after the steel cage is positioned, the embedded anchor nuts are installed, and the nuts are welded and fixed on the vertical edge steel bars to ensure that the bolts are firmly positioned; the side formwork is installed on the formwork platform, and concrete is poured and solidified to the age;

[0018] Step 2.2: After the prefabricated shear wall is hoisted into place, tie the steel bars of the post-cast edge components, install the bolts, and finally support the formwork and pour the edge component concrete;

[0019] Step 2.3: After the concrete strength reaches the design requirements, remove the support.

[0020] In step 3, the design and construction method of the composite slab without reinforcement is as follows: Step 3.1, the composite slab is installed to

[0021] After the short connecting bars are in place, three vertical transverse reinforcements are set on the upper part of the short bars, with a spacing of no more than 200mm; Step 3.2, design the short connecting bars;

[0022] Step 3.3: Place the upper reinforcement and pour concrete.

[0023] The specific operation of step 3.2 is as follows: A. The calculation method is: As = M / 0.9h0, where: M is the bending moment at the calculation section, the support is taken, h0 is the effective height, the distance from the additional reinforcement to the upper reinforcement is taken, and the area of ​​As is not less than the bottom reinforcement area of ​​the composite slab;

[0024] B. Length L1 is the lap length of the connecting short reinforcement, which is determined according to the concrete strength;

[0025] C. The anchorage length of the connecting short reinforcement at the shear wall support shall not be less than 15d and shall pass through the center line of the wall.

[0026] In the step 3, the design and construction method of the reinforced composite slab is as follows: Step 3.4, after the shear wall is installed in place, the vertical connecting steel bars are inserted, and concrete is poured in the corrugated pipe;

[0027] Step 3.5, place the ring beam reinforcement;

[0028] Step 3.6, install the composite board;

[0029] Step 3.7: Place the upper reinforcement bars on the floor slab and pour concrete.

[0030] In step 4, the groove depth of the keyway is 30 mm, and the upper and lower spacing of the keyway is 200 mm.

[0031] In step 5, the temporary support anchor bolts are made of Q235 steel with a 4mm rough surface; a 10x10mm anchor plate is added to the end of the temporary support anchor bolt to ensure stability inside the concrete; the inner thread end of the temporary support anchor bolt is thickened to prevent splitting when overloaded.

[0032] The beneficial effects of the present invention are as follows: no steel bars are present on the six surfaces of the prefabricated wall of the present invention, the production is simple, the standardization is high, the construction precision is low, and when a 60mm corrugated pipe is used, the fault tolerance size is about 40mm, which is 10 times larger than that of the prior art, and the fault tolerance rate is high; and the problem that the grouting sleeve cannot detect the fullness is solved; the cost is low, the horizontal connection adopts bolt connection and anchoring for reliable operation, and the construction is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the horizontal connection of the present invention;

[0034] Figure 2 It is a schematic diagram of the structure of the vertical connection of the present invention;

[0035] Figure 3 It is a detailed structural diagram of the horizontal connection of the present invention;

[0036] Figure 4 This is a connection structure diagram of the non-ribbed composite plate of the present invention;

[0037] Figure 5 This is a connection structure diagram of the ribbed composite plate of the present invention;

[0038] Figure 6 It is a front view of the shear wall of the present invention;

[0039] Figure 7 for Figure 6 Left view of

[0040] Figure 8 for Figure 6 Stereoscopic image of

[0041] Fig. 9 It is a schematic diagram of the structure of the temporary support anchor bolt of the present invention;

[0042] Fig.10 It is a structural schematic diagram of the keyway of the present invention;

[0043] Fig.11 for Figure 2 Stereoscopic image of

[0044] Fig.12 It is the load-displacement curve diagram of each test piece with different grouting material strength of the present invention;

[0045] Fig.13 The load-displacement curves of different grout anchor steel bar bonding anchorage lengths of the test specimen of the present invention are shown in FIG.

[0046] Fig.14 , Fig.15 and Fig.16 This is a stress-strain curve diagram of the grout-anchored steel bar of the present invention. DETAILED DESCRIPTION

[0047] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0048] A design and construction method for a prefabricated shear wall without reinforcement, comprising the following steps:

[0049] Step 1: Figure 2 As shown, the vertical connection design and construction uses corrugated pipe holes and additional connecting steel bars to realize the transformation of steel bars from two rows to one row; the details are as follows: Step 1.1, design and determination of vertical connection length parameters, basic anchorage length L ab Determined by formula, take L ab =α·fy / ft·d, (α value: 0.16 for round steel bar, 0.14 for ribbed steel bar, 0.13 for spiral ribbed steel bar, fy is the design value of steel bar tensile strength, ft is the design value of concrete axial compressive strength, d is the diameter of vertical steel bar; to explore the influence of different anchorage lengths on the connection performance of the specimens, the anchorage length L a Take different coefficients and multiply them by their basic anchorage length L ab , L a =k*L ab , k is the anchorage length coefficient selected in this test; k are 0.4, 0.6, 0.8, 1.0, and 1.2 respectively.

[0050] Step 1.2: After the prefabricated wall reinforcement cage is in place, cut the length L of the corrugated pipe and insert it into the prefabricated wall reinforcement cage; L = L a ,L a The anchorage length is adjusted according to the concrete strength in the corrugated pipe;

[0051] Step 1.3: After the prefabricated wall is installed and positioned, the connecting steel bars are inserted into the corrugated tube, and concrete is poured into the corrugated tube; Step 1.4: The ring beam steel bars are installed;

[0052] Step 1.5: After the ring beam reinforcement is installed, hoist the composite slab;

[0053] Step 1.6, pouring the post-casting section concrete;

[0054] Step 1.7, hoist the upper prefabricated wall;

[0055] Step 1.8, pouring concrete inside the corrugated pipe;

[0056] Step 2: Figure 1 and Figure 3As shown in the figure, the horizontal connection design and construction, after the prefabricated shear wall is hoisted in place, the horizontal connection anchor bolts are installed to avoid the collision of steel bars during installation;

[0057] The specific operation of step 2 is as follows: Step 2.1, wall production: after the steel cage is positioned, the embedded anchor nuts are installed, and the nuts are welded and fixed on the vertical edge steel bars to ensure that the bolts are firmly positioned; the side formwork is installed on the formwork platform, and concrete is poured and solidified to the age;

[0058] Step 2.2: After the prefabricated shear wall is hoisted into place, tie the steel bars of the post-cast edge components, install the bolts, and finally support the formwork and pour the edge component concrete;

[0059] Step 2.3: After the concrete strength reaches the design requirements, remove the support.

[0060] Step 3: Figure 4 As shown, the design and construction of composite slab connection includes the design and construction method of composite slab with reinforcement and the design and construction method of composite slab without reinforcement;

[0061] In step 3, Figure 4 As shown, the design and construction method of the composite slab without reinforcement is as follows: Step 3.1, after the composite slab is installed in place, place the connecting short reinforcement, and set 3 vertical transverse reinforcements on the upper part of the short reinforcement, with a spacing of no more than 200mm;

[0062] Step 3.2, design the connecting short reinforcement;

[0063] Step 3.3: Place the upper reinforcement and pour concrete.

[0064] The specific operation of step 3.2 is as follows: A. The calculation method is: As = M / 0.9h0, where: M is the bending moment at the calculation section, the support is taken, h0 is the effective height, the distance from the additional reinforcement to the upper reinforcement is taken, and the area of ​​As is not less than the bottom reinforcement area of ​​the composite slab;

[0065] B. Length L1 is the lap length of the connecting short reinforcement, which is determined according to the concrete strength;

[0066] C. The anchorage length of the connecting short reinforcement at the shear wall support shall not be less than 15d and shall pass through the center line of the wall.

[0067] In step 3, if Figure 5 As shown, the design and construction method of the reinforced composite slab is as follows: Step 3.4, after the shear wall is installed in place, insert the vertical connecting steel bars and pour concrete in the corrugated tube;

[0068] Step 3.5, place the ring beam reinforcement;

[0069] Step 3.6, install the composite board;

[0070] Step 3.7: Place the upper reinforcement bars on the floor slab and pour concrete.

[0071] Step 4: Figure 6 , Figure 7 , Figure 8 and Fig.10 As shown in the figure, the design and construction method of the side keyway and the front diagonal brace of the prefabricated shear wall; the groove depth of the keyway is 30mm, and the upper and lower spacing of the keyway is 200mm.

[0072] Step 5: Fig. 9 As shown, the design and construction of temporary support anchor bolts. In step 5, the temporary support anchor bolts are made of Q235 steel, and the surface is provided with a 4mm concave-convex rough surface; a 10x10mm anchor plate is added to the end of the temporary support anchor bolt to ensure stability inside the concrete; the inner thread end of the temporary support anchor bolt is thickened to prevent splitting when overloaded.

[0073] Test piece test:

[0074] The cross-sectional dimensions of the test design components are 200mm×200mm, the height is 700mm, and the protective layer thickness is 25mm. Basic anchor length L ab According to the formula given in the Code for Design of Concrete Structures (GB 50010-2010), L ab =α·fy / ft·d, where the ribbed steel bar shape coefficient is α=0.14. In order to explore the influence of different anchorage lengths on the connection performance of the specimens, the anchorage length L a Take different coefficients and multiply them by their basic anchorage length L ab , L a =k*L ab , k is the anchorage length coefficient selected in this test, which are 0.4, 0.6, 0.8, 1.0, and 1.2 respectively.

[0075] The main body of the specimen is cast with C30 ordinary concrete, and the corrugated pipe is poured with grouting materials of three strength grades, namely C40, C50 and C60. In order to prevent eccentricity, a central positioning steel plate is set and buried inside the specimen, keeping the clamping end steel bars and the grout anchor steel bars in the same straight line. The vertical steel bars in the main part of the specimen are 4C12, and the stirrups are C8@200. The diameter of the metal corrugated pipe is 40mm and the height is 600mm. Its main function is to pre-form holes and constrain grouting materials and grout anchor steel bars. The grout anchor steel bars are HRB400C14, which are adjusted to different anchoring lengths according to the test design, keeping the grout anchor steel bars aligned with the center of the corrugated pipe, and grouting connection after centering and insertion.

[0076] Test piece parameter table

[0077]

[0078]

[0079] Note: The specimen number format is "AB", where "A" represents the strength grade of the grouting material and "B" represents the influence coefficient of the basic anchorage length of the grouting steel bar. For example, "50-0.8" means that the grouting material strength is C50 and the anchorage length is 0.8L ab (L ab The height of the specimens is 700mm, and 15 specimens are made in total.

[0080] Test piece production

[0081] (1) Steel formwork, metal corrugated pipe, and steel bar processing

[0082] The template size, cutting length of metal corrugated pipe and steel bar are determined according to the data in the design drawings and parameter tables, and professional equipment is used for cutting and processing. Professional workers process the steel template and make holes at corresponding positions on both ends. The inner diameter of the holes is larger than the outer diameter of the steel bar so that the steel bars at both ends are exposed, while ensuring that the slurry anchor steel bar is accurately inserted into the center of the metal corrugated pipe.

[0083] (2) Strain gauges attached to mortar anchor reinforcement

[0084] In order to measure the strain change of the grout-anchored steel bar during loading, strain gauges are pasted at the four equal points of the inserted part of the grout-anchored steel bar, and epoxy resin is applied on the outside of the pasted strain gauges for protection.

[0085] (3) Steel cage, center positioning steel plate and metal corrugated pipe are placed into the mold

[0086] According to the drawings, assemble and position the components. The installation sequence is: first tie the steel cage, place the center positioning steel plate and metal corrugated pipe into the mold for positioning, and then expose the steel bar through the hole at one end of the template.

[0087] (4) Concrete pouring and maintenance

[0088] Before each component is put into the mold, the inside of the template is oiled to facilitate demoulding of the specimens later; before pouring concrete, the specimens are numbered according to Table 1.1, and the relative positions of the steel bars, center positioning steel plates, corrugated pipes and U-shaped stirrups (if any) are rechecked; the specimens are demoulded after standard curing for 7 days, and then cured for 28 days before grouting and reinforcing of the corrugated pipes.

[0089] (5) Grouting and inserting reinforcement

[0090] Use a grouting machine to carry out grouting and grouting treatment, and use a foam board to seal one end of the corrugated pipe grouting reinforcement to prevent the slurry from flowing out, and at the same time play a positioning role to ensure that the grout anchor steel bar is inserted into the corrugated pipe in the center.

[0091] Loading method and measurement content

[0092] The test loading system was adjusted and formulated with reference to the Grade I 100% joint test standard of the Technical Code for Mechanical Connection of Reinforcement Bars (JGJ 107-2016), and in light of the actual characteristics of the constrained slurry-anchor connection.

[0093] (1) Loading scheme

[0094] This test mainly studies the connection performance of the new connection nodes of the vertical reinforcement of the prefabricated shear wall, and 17 specimens are designed for pull-out tests. The loading scheme adopts unidirectional tensile loading. According to the relevant provisions of the "Standard for Test Methods of Concrete Structures" (GB50152-2012), and considering the actual situation of the loading device, a graded loading method is selected, with each 1kN as a level, and the load holding state is maintained for 30 seconds at each level to record data and observe test phenomena until the test ends when the anchor is damaged, the reinforcement is pulled out, the reinforcement is broken, or the specimen is damaged.

[0095] (2) Loading device

[0096] The loading device consists of a 50t through-type hydraulic jack and a special steel frame. The 50t through-type hydraulic jack consists of a hydraulic jack, a joystick and a digital pressure gauge; the special steel frame consists of four threaded steel columns, a pressure-bearing steel plate and bolts.

[0097] (3) Measurement content

[0098] During and after loading, the crack development and damage phenomena of the specimens at each stage were observed, and the yield load, failure load, and the strain of the grout anchor steel bars and U-shaped stirrups corresponding to each load level, the slip of the grout anchor steel bars, and the total elongation of the specimens were recorded.

[0099] a. The load value at each stage is recorded by the digital pressure gauge equipped with the hydraulic jack.

[0100] b. During the loading process, the stress and strain of the grout anchor reinforcement and U-shaped stirrups are collected by the strain acquisition system. To ensure accurate readings, check whether all strain gauges and strain acquisition instruments are intact before the test.

[0101] Strain gauge pasting position: Paste the strain gauge on the quarter-divided points of the steel bars in the anchorage section of each specimen. Paste the strain gauge on each U-shaped stirrup.

[0102] c. Record the amount of steel bar slippage during the test of the anchoring section. Set up the displacement meter support to fix the displacement meter, weld the steel bar to the free end of the grout anchor reinforcement, and take the displacement meter measurement value at W3 minus the average value of W1 and W2 as the amount of steel bar slippage.

[0103] Position of displacement meter: Two displacement meters W1 and W2 are arranged symmetrically on the left and right sides of the concrete surface on one side of the specimen's slurry anchor reinforcement. The steel bar is welded to the slurry anchor reinforcement at the interface between the slurry anchor reinforcement and the concrete, and the displacement meter W3 is placed.

[0104] d. Displacement meters are installed at both the free end and the loading end of the grout anchor reinforcement to facilitate drawing the load-displacement curve later.

[0105] Displacement meter position: Displacement meters W4 and W5 are installed on the steel bars at both ends of the specimen.

[0106] Observation and analysis objects: crack development and damage phenomenon of specimens, load-displacement curve of steel bar tension, slippage of slurry anchor steel bar, load-strain curve of slurry anchor steel bar anchorage section, and load-strain curve of stirrups.

[0107] Summary of test results

[0108] The data collected during the test loading process mainly include load values, grout anchor steel bar strain values, displacement counter values, etc. The following table lists the yield load (the load value corresponding to the yield of the specimen) and the ultimate load (the load value corresponding to the failure of the specimen) of each specimen in the test; the yield strength and ultimate strength of the connecting steel bar under this load are calculated; the elongation of the steel bar and the slip of the free end of the grout anchor steel bar at the time of failure; and the failure mode of the specimen when it fails.

[0109] Summary of test results under uniaxial tensile loading system

[0110]

[0111] From the comparison of the test results in the table, it can be seen that the bonding anchorage length of the grout anchor steel bar is l a , 1.2l a When the bonding anchorage length is less than l, even if the grouting strength is equivalent to C40, C50, and C60, the failure mode is still steel bar breaking failure, which shows that the basic anchorage length in the specification is very reasonable. a When the load was 1000MW, all specimens with different grouting material strengths slipped during loading, and the bonding anchorage was damaged and the bellows were pulled out before reaching the yield stage. The ultimate load was much lower than the ultimate load when the steel bar was pulled off, indicating that the grouting material strength was too low and the bonding length of the grout anchor and steel bar was insufficient. It was preliminarily proved that low-strength grouting material would lead to poor bonding and anchoring effect of the grout anchor connection, which could not meet the performance requirements of the grout anchor connection.

[0112] Analysis of the influence of grouting material strength

[0113] Load-displacement curve

[0114] During the test, the load value and its corresponding elongation of the anchor steel bar were recorded with the help of the digital pressure gauge and displacement meter equipped with the through-type jack, and the load-displacement curve was drawn. Fig.12 As shown,

[0115] Analysis of the influence of bonding length of grout anchor reinforcement

[0116] The collected data were classified and summarized, and the load-displacement curve comparison diagram of each specimen with different grout anchor reinforcement bond strength was drawn, such as Fig.13 shown.

[0117] Load displacement curve, such as Fig.13 As shown, from Fig.13 It can be seen that:

[0118] 1) The effect of the bonding anchorage length of the grout anchor steel on the anchorage performance of the specimen is particularly significant. When the anchorage length is 0.4lab and 0.6lab, the specimen has not undergone an obvious yield stage, the bonding anchorage has been destroyed, and the steel bar has slipped or even pulled out in large quantities; when the anchorage length is 0.8lab, the specimen has not reached the limit state after the yield stage, but has slipped with the increase of load, the bonding channel is connected, and the specimen is destroyed; when the anchorage length is 1.0lab and 1.2lab, it has reached or exceeded the basic anchorage length in the specification, and the specimen has experienced a complete elastic stage, yield stage, strengthening stage, and steel bar necking and breaking stage. The failure type is steel bar breaking. Only a small amount of slip occurs during the failure of the specimen in the later stage of loading, indicating that its bonding anchorage performance is relatively good.

[0119] 2) In Figures (a) and (b), when the strength of the grouting material is low and is not greater than the basic anchoring length, the ultimate load of the specimen increases with the increase of the anchoring length, and the bonding anchoring performance is greatly enhanced; when the anchoring length is 1.2lab, the ultimate load of the specimen increases, and the steel bars reach the limit state in the later stage of loading, and the steel bars break, so the ultimate displacement at the time of failure decreases instead.

[0120] The stress-strain curve of grout anchor reinforcement is as follows: Fig.14 , Fig.15 and Fig.16 As shown in the figure:

[0121] Generally speaking, when the strength of the grouting material is the same, under the same load, the longer the bonding anchorage length of the grout anchor steel bar, the greater the strain value of the steel bar at the same position. Due to the low strength of the grouting material and the loose grouting, the internal stress state of the corrugated pipe is also more complicated, the bond force of the grout anchor steel bar is unstable, and the strain change does not show a clear pattern.

[0122] The calculation formula of anchorage length is given: La=k*Lab, where k is the anchorage length coefficient, ≥0.8.

[0123] Give the corresponding table of metal corrugated pipe specifications (inner diameter) and vertical steel bar diameter

[0124] Correspondence table between metal corrugated pipe specifications (inner diameter) and vertical steel bar diameters

[0125] Vertical steel bar diameter / mm 12 / 14 16 / 18 20 / 22 25 Bellows specification / mm 65 70 75 80 .

Claims

1. A design and construction method for a prefabricated shear wall without reinforcement, characterized in that: The following steps are included: Step 1: Design and construction of vertical connection, with the help of corrugated pipe hole making, additional connecting steel bars are used to realize the transformation of steel bars from two rows to one row; the details are as follows: Step 1.1: Design and determination of vertical connection length parameters, basic anchorage length L ab Determined by the formula, take L ab =α·fy / ft·d, α value: 0.16 for round steel bar, 0.14 for ribbed steel bar, 0.13 for spiral ribbed steel bar, fy is the design value of steel bar tensile strength, ft is the design value of concrete axial compressive strength, d is the diameter of vertical steel bar; the influence of different anchorage lengths on the connection performance of the specimens, anchorage length L a Take different coefficients and multiply them by their basic anchorage length L ab , L a =k*L ab , k is the anchorage length coefficient selected in this test; Step 1.2: After the prefabricated wall reinforcement cage is in place, cut the length L of the corrugated pipe and insert it into the prefabricated wall reinforcement cage; L = L a ,L a The anchorage length is adjusted according to the concrete strength in the corrugated pipe; Step 1.3: After the prefabricated wall is installed and positioned, the connecting steel bars are inserted into the corrugated tube, and concrete is poured into the corrugated tube; Step 1.4, install the ring beam reinforcement; Step 1.5: After the ring beam reinforcement is installed, hoist the composite slab; Step 1.6, pouring the post-casting section concrete; Step 1.7, hoist the upper prefabricated wall; Step 1.8, pouring concrete inside the corrugated pipe; Step 2: Design and construct the horizontal connection. After the prefabricated shear wall is hoisted in place, install the horizontal connection anchor bolts to avoid steel bar collision during installation. Step 3: Design and construction of composite slab connection, which includes the design and construction method of composite slab with reinforcement and the design and construction method of composite slab without reinforcement; Step 4: Design and construction method of the side keyway and front diagonal brace of the prefabricated shear wall; Step 5: Design and construction of temporary support anchor bolts.

2. The design and construction method of prefabricated shear wall without reinforcement according to claim 1 is characterized in that: The specific operation of step 2 is as follows: Step 2.1, wall production: after the steel cage is positioned, the embedded anchor nuts are installed, and the nuts are welded and fixed on the vertical edge steel bars to ensure that the bolts are firmly positioned; the side formwork is installed on the formwork platform, and concrete is poured and solidified to the age; Step 2.2: After the prefabricated shear wall is hoisted into place, tie the steel bars of the post-cast edge components, install the bolts, and finally support the formwork and pour the edge component concrete; Step 2.3: After the concrete strength reaches the design requirements, remove the support.

3. The design and construction method of prefabricated shear wall without reinforcement according to claim 1 is characterized in that: In step 3, the design and construction method of the composite slab without reinforcement is as follows: step 3.1, after the composite slab is installed in place, the connecting short reinforcement is placed, and 3 vertical transverse reinforcements are arranged on the upper part of the short reinforcement, with a spacing of no more than 200mm; Step 3.2, design the connecting short reinforcement; Step 3.3: Place the upper reinforcement and pour concrete.

4. The design and construction method of prefabricated shear wall without reinforcement according to claim 3 is characterized in that: The specific operation of step 3.2 is as follows: A. The calculation method is: As = M / 0.9h0, where: M is the bending moment at the calculation section, the support is taken, h0 is the effective height, the distance from the additional reinforcement to the upper reinforcement is taken, and the area of ​​As is not less than the bottom reinforcement area of ​​the composite slab; B. Length L1 is the lap length of the connecting short reinforcement, which is determined according to the concrete strength; C. The anchorage length of the connecting short reinforcement at the shear wall support shall not be less than 15d and shall pass through the center line of the wall.

5. The design and construction method of prefabricated shear wall without reinforcement according to claim 1 is characterized in that: In the step 3, the design and construction method of the reinforced composite slab is as follows: Step 3.4, after the shear wall is installed in place, the vertical connecting steel bars are inserted, and concrete is poured in the corrugated pipe; Step 3.5, place the ring beam reinforcement; Step 3.6, install the composite board; Step 3.7: Place the upper reinforcement bars on the floor slab and pour concrete.

6. The design and construction method of prefabricated shear wall without reinforcement according to claim 1 is characterized in that: In step 4, the groove depth of the keyway is 30 mm, and the upper and lower spacing of the keyway is 200 mm.

7. The design and construction method of prefabricated shear wall without reinforcement according to claim 1 is characterized in that: In step 5, the temporary support anchor bolts are made of Q235 steel with a 4mm rough surface; a 10x10mm anchor plate is added to the end of the temporary support anchor bolt to ensure stability inside the concrete; the inner thread end of the temporary support anchor bolt is thickened to prevent splitting when overloaded.

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