Construction method for reinforcing masonry parapet wall by in-situ vertical prestressed tendon

Abstract

This invention discloses a construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons, comprising the following steps: 1. Designing prestressed tendon parameters and verifying the reinforcement effect; 2. Drilling and positioning holes to obtain anchoring holes; 3. Injecting anchoring adhesive into the anchoring holes and screwing in the prestressed tendons; 4. Grinding the top surface of the pre-anchored masonry parapet wall, fitting a rectangular steel plate, and screwing in anchor nuts; 5. Tensioning the anchors in the masonry parapet wall; 6. Encapsulating the anchors with polymer cement mortar to complete the construction of the internal vertical prestressed tendon-reinforced masonry parapet wall. This invention establishes a deep anchorage between the masonry parapet wall and the underlying main structure through internal anchoring technology, and improves the shear bearing capacity of the masonry parapet wall by increasing the vertical compressive stress of the horizontal section of the masonry parapet wall using vertical prestressing, while not damaging the original waterproof layer and spatial layout, thus completing the construction of the internal vertical prestressed tendon-reinforced masonry parapet wall.

Description

Technical Field

[0001] This invention belongs to the technical field of reinforced masonry parapet walls, specifically relating to a construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons. Background Technology

[0002] Recent earthquake surveys have shown that masonry parapet walls, as cantilever structures at the top, are prone to significant whiplash effects under earthquake loads. Furthermore, masonry parapet walls in seismic zones often suffer from design and construction defects such as low mortar strength, poor anchoring measures, and lack of connection with the main structure. Under earthquake loads, they are susceptible to typical damages such as out-of-plane overturning instability and root shear fracture, leading to hazards such as damage to roof equipment, tearing of waterproofing systems, and falling objects from heights, posing a serious threat to people's lives and property.

[0003] Currently, seismic reinforcement methods for masonry parapet walls often require drilling through the waterproof layer on the inner surface of the roof and the masonry parapet wall, which damages the integrity of the waterproof membrane. On the other hand, the newly added reinforcement components will occupy the effective space of the roof, and when the roof has other usage needs, the operating space for reinforcement work will be severely limited.

[0004] Therefore, a construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons is needed. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a construction method for reinforcing masonry parapet walls with internal vertical prestressing tendons. This method utilizes the bonding force of the anchoring adhesive as the bottom anchoring end of the prestressing tendons, and sets a tensioning end at the top to apply appropriate tension. On the one hand, it establishes a deep anchorage between the masonry parapet wall and the underlying main structure through internal rebar anchoring technology; on the other hand, it utilizes vertical prestressing to increase the vertical compressive stress in the horizontal section of the masonry parapet wall, thereby improving the shear bearing capacity of the masonry parapet wall. This solves the problem of completing the construction of masonry parapet walls reinforced with internal vertical prestressing tendons without damaging the original waterproof layer and spatial layout.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a construction method for reinforcing a masonry parapet wall with internal vertical prestressing tendons, characterized in that the method involves vertically setting prestressing tendons inside the masonry parapet wall, anchoring the prestressing tendons at the bottom of the ring beam using structural adhesive, and then applying prestress to the prestressing tendons to reinforce the masonry parapet wall, specifically including the following steps: Step 1: Design the parameters of the prestressed tendons based on the parameters of the masonry parapet wall, including the size, quantity, spacing, anchorage length, and design tension of the prestressing, and verify the reinforcement effect. Step 2: According to the prestressed tendon parameters designed in Step 1, make equally spaced holes on the top surface of the masonry parapet wall. Then, drill vertically downwards from the top of the masonry parapet wall, and the depth should penetrate the masonry parapet wall and enter the bottom ring beam. After that, brush off the floating dust on the hole wall, blow away the residue, wipe the hole wall, and obtain the rebar hole. Step 3: Inject anchoring adhesive into the anchoring holes obtained in Step 2 from the bottom up, then slowly screw the prestressed tendons into the anchoring holes, and then cure them to obtain the pre-anchored masonry parapet wall. Step 4: Grind around the anchor holes on the top surface of the pre-reinforced masonry parapet wall obtained in Step 3, then lay the lining, and then fit the pre-stressed tendons with a rectangular steel plate with holes and screw in the anchor nuts to obtain a masonry parapet wall with anchors. Step 5: Using a hydraulic jack and a pressure gauge, tension the anchorages in the masonry parapet wall with anchorages from Step 4; Step Six: After the tensioning in Step Five is completed, cut off the prestressing tendons that expose the anchor nuts, then apply epoxy zinc-rich anti-corrosion paint to the anchor, fill the circumferential gap between the rectangular steel plate and the prestressing tendons with grout, and encapsulate the anchor with polymer cement mortar to complete the construction of the internal vertical prestressing tendon reinforcement masonry parapet wall.

[0007] This invention first designs the parameters of the prestressing tendons based on the parameters of the masonry parapet wall and verifies the reinforcement effect to ensure its effectiveness. By using evenly spaced holes for positioning, the stress on the masonry parapet wall is made uniform, again ensuring the reinforcement effect. Vertical downward drilling and injection of anchoring adhesive are used to implant the prestressing tendons into the masonry parapet wall for reinforcement. Grinding ensures the flatness of the fitted rectangular steel plates to prevent stress concentration. Laying a lining layer eliminates stress concentration caused by unevenness on the top surface of the masonry parapet wall. An anchor is formed by fitting the perforated rectangular steel plates and anchor nuts, facilitating the tensioning of the prestressing tendons through the anchor. Tensioning actively applies vertical prestress to the masonry parapet wall. By cutting off the exposed prestressing tendons with anchor nuts, the exposed length is shortened to facilitate subsequent rust prevention by polymer cement mortar sealing. Epoxy zinc-rich anti-corrosion paint is applied to prevent rusting of the prestressing tendons, rectangular steel plates, and anchor nuts. Grouting fills the circumferential gap between the rectangular steel plate and the prestressing tendons, sealing the circumferential gap between the openings in the rectangular steel plate and the prestressing tendons, thus preventing the penetration of moisture and oxygen. The anchorage is then completely sealed with polymer cement mortar, ensuring that the reinforced masonry parapet wall maintains the same appearance as the original structure and possesses excellent fire resistance and weathering resistance.

[0008] The above-mentioned construction method for reinforcing a masonry parapet wall with internal vertical prestressed tendons is characterized in that, in step one, the prestressed tendons are precision-rolled threaded steel bars with a diameter of 15mm~25mm, a length equal to the depth of the anchor hole plus the thickness of the rectangular steel plate and the height of the anchor nut plus 10mm~30mm, the spacing of the prestressed tendons along the length of the masonry parapet wall is 500mm~1200mm, the number of prestressed tendons is the length of the masonry parapet wall divided by the spacing of the prestressed tendons along the length of the masonry parapet wall, and the anchorage length of the prestressed tendons in the ring beam is 160mm~220mm. This invention controls the diameter of the prestressing tendons to ensure reinforcement while preventing excessive diameter and avoiding excessively large holes that could negatively impact the masonry parapet wall. The length of the prestressing tendons is controlled to be the depth of the anchoring hole plus the thickness of the rectangular steel plate and the height of the anchor nut, plus 10mm-30mm of masonry to provide sufficient space for tensioning operations at the top of the parapet wall. The spacing of the prestressing tendons, i.e., the number of prestressing tendons, is designed based on the required increase in shear capacity for the masonry parapet wall. Too small a spacing results in too many holes, causing significant damage to the parapet wall; too large a spacing leads to insignificant reinforcement. The anchorage length of the prestressing tendons within the ring beam is controlled—it must be 20mm-30mm less than the ring beam height—to prevent penetration. Since the reinforced concrete ring beam has higher strength and density than the underlying brick masonry, controlling the anchoring holes within the ring beam ensures reliable anchorage and pull-out resistance for the prestressing tendons. If the tendons penetrate the ring beam into the lower main structure's brick masonry, the anchorage force of the brick section decreases, and it interferes with the lower main structure.

[0009] The above-mentioned construction method for reinforcing a masonry parapet wall with internal vertical prestressed tendons is characterized in that the verification of the reinforcement effect in step one includes the following process: The design value of the anchorage pull-out bearing capacity of the prestressed tendons at the bottom of the ring beam is verified as follows:

[0010] in, F This is the design tension force for prestressing, expressed in N. N bd This is the design value of the anchorage pull-out bearing capacity, in N. or For safety factor, d is the diameter of the prestressing tendon, in mm. l a Anchorage length, in mm. f bd This is the design value for the bonding strength of the rebar adhesive, in N / mm². 2 ; The local compressive bearing capacity of the masonry parapet wall is checked, as follows: ; in,N l This is the design value of the axial force under localized compression of the prestressed tendon, in N. c This is the coefficient for increasing the local compressive strength of the masonry parapet wall. f This is the design value of the compressive strength of the masonry parapet wall, in N / mm². 2 , A l This represents the localized compressive area of ​​the masonry parapet wall, in mm. 2 ; The stress of the prestressing tendons is checked, as follows: ; ; in, F n The maximum prestressing force applied to the prestressing tendons, expressed in N. s con This represents the maximum prestressing stress of the prestressing tendon, expressed in N / mm². 2 , A s This represents the cross-sectional area of ​​the prestressing tendons, in mm². 2 , f pyk This is the standard value of the yield strength of prestressed tendons, in N / mm². 2 ; The average compressive stress of the horizontal section was checked, and the effect of prestressing tendons on improving the shear bearing capacity of the masonry parapet wall was calculated, as follows: ; in, s t The total prestress applied to the prestressing tendons, expressed in N / mm². 2 , n The number of prestressing tendons, F This is the design tension force for prestressing, expressed in N. b This refers to the width of the masonry parapet wall, in mm. L This refers to the length of the masonry parapet wall, in mm. f This is the design value of the compressive strength of the masonry parapet wall, in N / mm². 2 ; ; in, V This is the design value of the horizontal section shear capacity of the reinforced masonry parapet wall, in N. f v This is the design value of the shear strength of the masonry, in N / mm². 2 , α Correction coefficient ,m The influence coefficient of combined shear and compression forces ,s 0 represents the average compressive stress in the horizontal section, in MPa. A This refers to the horizontal cross-sectional area of ​​the masonry parapet wall, in mm². 2 This invention verifies the design value of the anchorage pull-out bearing capacity of the prestressed tendons anchored into the ring beam at the bottom. The pull-out bearing capacity of the prestressed tendons is a controlling factor and must be greater than the design tension force of the prestressing to ensure that the deep anchorage of the prestressed tendons in the bottom ring beam has sufficient pull-out capacity, preventing overall pull-out failure of the prestressed tendons during the tensioning stage. The calculation results show whether the designed anchorage length is safe. The invention also verifies the local compressive bearing capacity of the masonry parapet wall, specifically whether the masonry parapet wall below the rectangular steel plate at the top tensioning end will experience local crushing under concentrated loads. The calculation results... This is used to determine the minimum area and thickness of rectangular steel plates, to verify the stress of prestressing tendons, to control the stress level of prestressing tendons during tensioning, to ensure that they are in a safe and reasonable low prestress range, and to prevent the prestressing tendons from yielding or breaking during tensioning. It is also used to verify the average compressive stress of the horizontal section and to calculate the effect of prestressing tendons on improving the shear bearing capacity of the masonry parapet wall. This controls the compressive stress generated in the horizontal section of the wall due to the application of prestress, so as to prevent the masonry parapet wall from being crushed axially due to excessive axial compression, and to reasonably increase its normal stress to improve the shear bearing capacity of the masonry parapet wall.

[0011] The above-mentioned construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons is characterized in that, before the hole layout and positioning in step two, the existing tie bars and reinforcing bars in the masonry parapet wall and ring beam are scanned, and the existing tie bars and reinforcing bars are avoided during hole layout and positioning; in the scanning, at least 6 evenly distributed measuring points are taken for each masonry parapet wall. This invention avoids damaging the existing reinforcement structure inside the masonry parapet wall by avoiding the existing tie bars and reinforcing bars.

[0012] The above-mentioned construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons is characterized by the following steps: in step two, the hole positioning is combined with a laser level and chalk line marking; the drilling is done using a dry water drill; the diameter of the anchoring hole is 4mm to 8mm larger than the diameter of the prestressed tendon; the removal of loose dust from the hole wall is repeatedly done with a long-handled steel brush; the removal of residue is done with a high-pressure blower or air compressor; and the wiping of the hole wall is done with alcohol-soaked cotton balls. This invention ensures that the prestressed tendon can be smoothly screwed into the elongated hole by controlling the diameter of the anchoring hole to be larger than the diameter of the prestressed tendon, and ensures the fullness of the structural adhesive and optimal anchoring force. By brushing off loose dust from the hole wall, blowing off residue, and wiping the hole wall, the anchoring hole is kept dust-free, ensuring the bonding effect between the prestressed tendon and the anchoring hole.

[0013] The above-mentioned construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons is characterized in that, in step three, the prestressed tendons are pre-cleaned threaded steel bars, and the curing temperature is room temperature for no less than 24 hours. This invention, by using pre-cleaned threaded steel bars, prevents the introduction of impurities and improves the reinforcement effect. By controlling the curing parameters, it ensures full adhesion between the prestressed tendons and the anchor holes, achieving maximum bond strength.

[0014] The above-mentioned construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons is characterized in that the grinding in step four is carried out using an angle grinder, the lining is an epoxy mortar leveling layer with a thickness of 5mm to 10mm or a rubber pad with a thickness of 3mm to 5mm, the thickness of the rectangular steel plate is not less than 10mm, the side length is 80% to 90% of the thickness of the masonry parapet wall, and the diameter of the opening of the rectangular steel plate is 4mm to 8mm larger than the diameter of the prestressed tendon. This invention ensures the flatness of the rectangular steel plate by grinding the area where it will be installed, thus preventing stress concentration. During the tensioning stage, if the rectangular steel plate directly contacts the uneven brickwork, it can easily generate local high pressure and crush the masonry. By setting an epoxy mortar leveling layer or a rubber pad as a lining, stress concentration caused by unevenness of the parapet wall surface can also be eliminated. By controlling the thickness and side length of the rectangular steel plate, sufficient rigidity is ensured when the steel plate is subjected to tension, avoiding bending deformation or local yielding, and preventing local crushing of the masonry. Appropriate edges are reserved on both sides of the steel plate.

[0015] The above-mentioned construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons is characterized by the following steps: First, initial tensioning is performed, applying 5% to 15% of the design prestress. Hydraulic jacks are used to tension the exposed ends of the prestressing tendons, and anchor nuts are tightened to ensure tight contact between the rectangular steel plate, lining, and anchor nuts. After the initial tensioning is held for 1 to 2 minutes, graded loading is performed, i.e., loading is performed at 25% to 35%, 55% to 65%, and 100% of the design prestress. After holding the load for 5 minutes, and confirming no slippage or pressure drop, the anchor nuts are tightened to lock the structure. In this invention, initial tensioning is performed first to ensure tight contact between the rectangular steel plate, lining, and anchor nuts. Graded loading with multiple points synchronized prevents excessive force at a single node from causing local instability of the masonry parapet wall.

[0016] Compared with the prior art, the present invention has the following advantages: 1. This invention utilizes the bonding force of the anchoring adhesive as the bottom anchoring end of the prestressing tendon, and sets a tensioning end at the top to apply appropriate tension. On the one hand, it establishes a deep anchoring between the masonry parapet wall and the lower main structure through internal anchoring technology. On the other hand, it uses vertical prestress to increase the vertical compressive stress of the horizontal section of the masonry parapet wall to improve the shear bearing capacity of the masonry parapet wall. At the same time, it does not damage the original waterproof layer and spatial layout, thus completing the construction of the internal vertical prestressing tendon reinforcement of the masonry parapet wall.

[0017] 2. This invention designs the parameters of the prestressing tendons based on the parameters of the masonry parapet wall and verifies the reinforcement effect. This ensures that the deep anchorage of the prestressing tendons in the bottom ring beam has sufficient pull-out resistance, preventing the overall pull-out failure of the prestressing tendons during the tensioning stage. It controls the stress level of the prestressing tendons during tensioning, ensuring that it is within a safe and reasonable low prestress range, preventing the prestressing tendons from yielding or breaking during tensioning. It also controls the compressive stress generated in the horizontal section of the wall due to the applied prestress, preventing the masonry parapet wall from being axially crushed due to excessive axial compression, and reasonably increasing its normal stress to improve the shear bearing capacity of the masonry parapet wall.

[0018] 3. This invention controls the diameter of the prestressing tendons to ensure reinforcement while preventing excessive diameter. It controls the length of the prestressing tendons to meet the tensioning work space at the top of the parapet wall. The spacing of the prestressing tendons, i.e. the number of prestressing tendons, is designed and controlled according to the required shear bearing capacity of the masonry parapet wall. By controlling the anchorage length of the prestressing tendons in the ring beam, it prevents the prestressing tendons from penetrating the ring beam and ensures that the prestressing tendons obtain reliable anchorage pull-out bearing capacity.

[0019] 4. In this invention, initial tensioning is first performed to ensure that the rectangular steel plate, lining and anchor nuts fit together tightly. Through graded loading and multi-point synchronous loading, the local instability of the masonry parapet wall is prevented from being caused by excessive force at a single node.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the masonry parapet wall reinforced with internal vertical prestressed tendons in this invention.

[0022] Figure 2 yes Figure 1 Enlarged view of point A.

[0023] Figure 3 This is a schematic diagram of the structure of the annular masonry parapet wall reinforced with internal vertical prestressing tendons in this invention.

[0024] Figure 4 yes Figure 3 Enlarged view of point B.

[0025] Explanation of reference numerals in the attached figures: Detailed Implementation

[0026] Figure 1 This is a schematic diagram of the structure of the masonry parapet wall 1 reinforced with internal vertical prestressed tendons 2 in this invention. Figure 2 yes Figure 1 Enlarged view of point A, from Figure 1 and Figure 2 As can be seen, prestressed tendons 2 are vertically installed inside the masonry parapet wall 1, and the prestressed tendons 2 are anchored at the bottom of the ring beam 3. The part of the prestressed tendons 2 that is exposed above the masonry parapet wall 1 is provided with a lining layer 4, a rectangular steel plate 5 and an anchoring nut 6 in sequence. The lower part of the ring beam 3 is the main structure 7.

[0027] Figure 3 This is a schematic diagram of the structure of the annular masonry parapet wall 1 reinforced with internal vertical prestressed tendons 2 in this invention. Figure 4 yes Figure 3 Enlarged view at point B, from Figure 3 and Figure 4 As can be seen, prestressed tendons 2 are vertically installed inside the annular masonry parapet wall 1, and rectangular steel plates 5 and anchor nuts 6 are installed on the upper part of the prestressed tendons 2.

[0028] Example 1 The height of the masonry parapet wall 1 in this embodiment h It is 600mm wide. b It is 240mm long. L The ring beam is 10000mm long. The concrete strength used for ring beam 3 is C20. The masonry parapet wall 1 uses ordinary bricks with a strength of MU10, mortar with a strength of M2.5, and the rebar adhesive is Grade A adhesive. The design bond strength is [value missing]. f bd Take 2.3 MPa.

[0029] This embodiment includes the following steps: Step 1: Design the parameters of the prestressed tendons 2 based on the parameters of the masonry parapet wall 1, including dimensions, quantity, spacing, anchorage length, and design prestressing tension, and verify the reinforcement effect; the prestressed tendons 2 are PSB830 prestressed fine-rolled threaded steel bars, and the diameter of the prestressed tendons 2 is... d The length is 18mm, the depth of the anchor hole plus the thickness of the rectangular steel plate 5 and the height of the anchor nut 6 plus 20mm, the horizontal spacing of the prestressing tendons 2 is 500mm, and the number is 20. The anchorage length inside the ring beam 3 is... l a It is 200mm; The design value of the anchorage pull-out bearing capacity of the prestressed tendon 2 anchored into the ring beam 3 is verified as follows:

[0030] in, F This is the design tension force for prestressing, expressed in N. N bd This is the design value of the anchorage pull-out bearing capacity, in N. or For safety reasons, d This refers to the diameter of prestressing tendon 2, in mm. l a Anchorage length, in mm. f bd This is the design value for the bonding strength of the rebar adhesive, in N / mm². 2 ; During verification, or Take 0.7, d It is 18mm. l a It is 200mm. f bd It is 2.3 MPa, calculated as follows N bd The design tension of the prestress is 18.2 kN. F The value is 18.2 kN; The local compressive bearing capacity of masonry parapet wall 1 is checked, as follows: ; in, N l This is the design value of the axial force under local compression of prestressed tendon 2, in N. c The coefficient for increasing the local compressive strength of the masonry parapet wall 1. f This is the design value of the compressive strength of the masonry parapet wall 1, in N / mm². 2 , A l The area under partial compression of the masonry parapet wall 1 is shown in mm. 2 ; During verification, c Take 2.0, f It is 1.30 MPa. A l 200mm × 200mm = 40000mm 2 Calculation N l The local pressure of prestressing tendon 2 is 104.0 kN. F =18.2kN, therefore the requirement is met; The stress of prestressed tendon 2 is checked as follows: ; ; in, F n The maximum prestressing force applied to prestressing tendon 2, in N. s con This represents the maximum prestress of prestressing tendon 2, in N / mm². 2 , A s This is the cross-sectional area of ​​prestressing tendon 2, in mm. 2 , f pyk This is the standard value of the yield strength of prestressed tendon 2, in N / mm². 2 ; During verification, f pyk It is 830 MPa, calculated as follows s con It is 705.5 MPa. A s It is 254.47mm. 2 Calculation F n It is 179.53 kN, as calculated above. F The stress is 18.2 kN, which meets the requirements, and prestressing tendon 2 is at a low prestress level. The average compressive stress of the horizontal section was checked, and the effect of prestressing tendons on improving the shear bearing capacity of the masonry parapet wall 1 was calculated, as follows: ; in, s t The total prestress applied to prestressing tendon 2, in N / mm². 2 , n The number of prestressing tendons 2, F This is the design tension force for prestressing, expressed in N. b The width of the masonry parapet wall 1 is in mm. L The length of the masonry parapet wall 1 is in mm. f This is the design value of the compressive strength of the masonry parapet wall 1, in N / mm². 2 ; During verification, F It is 18.2kN. b It is 240mm. L It is 10000mm. f It is 1.30 MPa, calculated as follows s t It is 0.15 MPa, less than 0.8. f= 1.04MPa, therefore the requirement is met; ; in, V This is the design value of the horizontal section shear capacity of the reinforced masonry parapet wall 1, in N. f v This is the design value of the shear strength of the masonry, in N / mm². 2 , α Correction coefficient ,m The influence coefficient of combined shear and compression forces ,s 0 represents the average compressive stress in the horizontal section, in MPa. A The horizontal cross-sectional area of ​​the masonry parapet wall 1 is in mm². 2 ; During verification, f v It is 0.08 MPa. α Take 0.60, m Take 0.24, A 2,400,000 mm 2 Before reinforcement, only the self-weight of the masonry parapet wall 1 was considered. s 0 is 0.01 MPa, after reinforcement s With a strength of 0.15 MPa, the calculated shear capacity of the unreinforced masonry parapet wall 1 was 195.46 kN, and the shear capacity of the reinforced masonry parapet wall 1 was 243.84 kN, representing a theoretical increase of approximately 24.8% in shear capacity. Step 2: Based on the prestressed tendon 2 parameters designed in Step 1, make equally spaced holes on the top surface of the masonry parapet wall 1. Then, drill vertically downwards from the top of the masonry parapet wall 1, penetrating the masonry parapet wall 1 and reaching the bottom ring beam 3. Afterwards, brush off the floating dust from the hole wall, blow away the residue, and wipe the hole wall to obtain the rebar holes. Before the hole positioning, scan the existing tie bars and rebars in the masonry parapet wall 1 and ring beam 3, and avoid the existing tie bars and rebars when positioning the holes. In the scanning, take 8 evenly distributed measuring points for one masonry parapet wall 1. The hole positioning is combined with a laser level and chalk line. The drilling is done with a dry water drill. The diameter of the rebar holes is 6mm larger than the diameter of the prestressed tendon 2. The floating dust on the hole wall is brushed off repeatedly with a long-handled steel brush. The residue is blown away with a high-pressure blower or air compressor. The hole wall is wiped with alcohol cotton balls. Step 3: Inject anchoring adhesive into the anchoring holes obtained in Step 2 from the bottom up, then slowly screw the prestressed tendon 2 into the anchoring hole, and then cure it to obtain the pre-anchored masonry parapet wall; the prestressed tendon 2 is a pre-cleaned threaded steel bar, and the curing temperature is room temperature and the time is not less than 24 hours. Step 4: Grind around the anchoring holes on the top surface of the pre-reinforced masonry parapet wall obtained in Step 3, then lay the lining layer 4, and then fit the prestressed tendon 2 with a rectangular steel plate 5 with holes, and screw in the anchoring nut 6 to obtain a masonry parapet wall with anchors; the grinding is carried out using an angle grinder, the lining layer 4 is an epoxy mortar smoothing layer with a thickness of 8mm, the rectangular steel plate 5 has a thickness of 12mm, the side length is 85% of the thickness of the masonry parapet wall 1, and the diameter of the opening of the rectangular steel plate 5 is 6mm larger than the diameter of the prestressed tendon 2; Step 5: Using a hydraulic jack and pressure gauge, tension the anchorages in the masonry parapet wall with anchorages from Step 4. The tensioning process is as follows: First, perform initial tensioning by applying 10% of the design tension force of the prestress. Use a hydraulic jack to tension the exposed end of the prestressing tendon 2 and tighten the anchor nut 6 to ensure that the rectangular steel plate 5, the lining 4, and the anchor nut 6 are tightly fitted. After the initial tensioning load is held stable for 1.5 minutes, perform graded loading, i.e., perform graded loading according to 30%, 60%, and 100% of the design tension force of the prestress. After holding the load for 5 minutes, and confirming that there is no slippage or pressure drop, tighten the anchor nut 6 to lock it. Step Six: After the tensioning in Step Five is completed, cut off the prestressing tendon 2 that is exposed to the anchor nut 6, then apply epoxy zinc-rich anti-corrosion paint to the anchor, fill the circumferential gap between the rectangular steel plate 5 and the prestressing tendon 2 with grout, and encapsulate the anchor with polymer cement mortar to complete the construction of the internal vertical prestressing tendon reinforced masonry parapet wall.

[0031] In this embodiment, the lining layer 4 may also be an epoxy mortar leveling layer with a thickness of 5 mm or an epoxy mortar leveling layer with a thickness of 10 mm.

[0032] Example 2 The height of the masonry parapet wall 1 in this embodiment h It is 400mm wide. b It is 240mm long. L The diameter is 6400mm. The ring beam 3 uses C20 concrete, the parapet wall 1 uses MU7.5 ordinary bricks, M1 mortar, and Class A adhesive for rebar installation. The design bond strength is [value missing]. f bd Take 2.3 MPa.

[0033] This embodiment includes the following steps: Step 1: Design the parameters of the prestressed tendons 2 based on the parameters of the masonry parapet wall 1, including dimensions, quantity, spacing, anchorage length, and design prestressing tension, and verify the reinforcement effect; the prestressed tendons 2 are PSB830 prestressed fine-rolled threaded steel bars, and the diameter of the prestressed tendons 2 is... dThe length is 15mm, the depth of the anchor hole plus the thickness of the rectangular steel plate 5 and the height of the anchor nut 6 plus 10mm, the horizontal spacing of the prestressing tendons 2 is 800mm, and the number of tendons is 8. The anchorage length inside the ring beam 3 is... l a It is 160mm; The design value of the anchorage pull-out bearing capacity of the prestressed tendon 2 anchored into the ring beam 3 is verified as follows:

[0034] in, F This is the design tension force for prestressing, expressed in N. N bd This is the design value of the anchorage pull-out bearing capacity, in N. or For safety reasons, d This refers to the diameter of prestressing tendon 2, in mm. l a Anchorage length, in mm. f bd This is the design value for the bonding strength of the rebar adhesive, in N / mm². 2 ; During verification, or Take 0.7, d It is 15mm. l a It is 160mm. f bd It is 2.3 MPa, calculated as follows N bd The design tension of the prestress is 12.1 kN. F The value is 12.1 kN; The local compressive bearing capacity of masonry parapet wall 1 is checked, as follows: ; in, N l This is the design value of the axial force under local compression of prestressed tendon 2, in N. c The coefficient for increasing the local compressive strength of the masonry parapet wall 1. f This is the design value of the compressive strength of the masonry parapet wall 1, in N / mm². 2 , A l The area under partial compression of the masonry parapet wall 1 is shown in mm. 2 ; During verification, c Take 2.0, f It is 1.09 MPa. A l 190mm × 190mm = 36100mm 2 CalculationN l The local pressure of prestressing tendon 2 is 78.7 kN. F =12.1kN, therefore the requirement is met; The stress of prestressed tendon 2 is checked as follows: ; ; in, F n The maximum prestressing force applied to prestressing tendon 2, in N. s con This represents the maximum prestress of prestressing tendon 2, in N / mm². 2 , A s This is the cross-sectional area of ​​prestressing tendon 2, in mm. 2 , f pyk This is the standard value of the yield strength of prestressed tendon 2, in N / mm². 2 ; During verification, f pyk It is 830 MPa, calculated as follows s con It is 705.5 MPa. A s It is 176.72mm. 2 Calculation F n It is 124.68 kN, as calculated above. F The value is 12.1kN, which meets the requirements, and prestressing tendon 2 is at a low prestress level; The average compressive stress of the horizontal section was checked, and the effect of prestressing tendons on improving the shear bearing capacity of the masonry parapet wall 1 was calculated, as follows: ; in, s t The total prestress applied to prestressing tendon 2, in N / mm². 2 , n The number of prestressing tendons 2, F This is the design tension force for prestressing, expressed in N. b The width of the masonry parapet wall 1 is in mm. L The length of the masonry parapet wall 1 is in mm. f This is the design value of the compressive strength of the masonry parapet wall 1, in N / mm². 2 ; During verification, F It is 12.1kN. b It is 240mm.L It is 6400mm. f It is 1.09 MPa, calculated as follows s t It is 0.063 MPa, which is less than 0.8. f= 0.872MPa, therefore the requirement is met; ; in, V This is the design value of the horizontal section shear capacity of the reinforced masonry parapet wall 1, in N. f v This is the design value of the shear strength of the masonry, in N / mm². 2 , α Correction coefficient ,m The influence coefficient of combined shear and compression forces ,s 0 represents the average compressive stress in the horizontal section, in MPa. A The horizontal cross-sectional area of ​​the masonry parapet wall 1 is in mm². 2 ; During verification, f v It is 0.06 MPa. α Take 0.60, m Take 0.24, A 1536000mm 2 Before reinforcement, only the self-weight of the masonry parapet wall 1 was considered. s 0 is 0.007 MPa, after reinforcement s With a strength of 0.07 MPa, the calculated shear capacity of the unreinforced masonry parapet wall 1 was 93.71 kN, and the shear capacity of the reinforced masonry parapet wall 1 was 107.64 kN, representing a theoretical increase of approximately 14.9% in shear capacity. Step 2: Based on the prestressed tendon 2 parameters designed in Step 1, make equally spaced holes on the top surface of the masonry parapet wall 1. Then, drill vertically downwards from the top of the masonry parapet wall 1, penetrating the masonry parapet wall 1 and reaching the bottom ring beam 3. Afterwards, brush off the floating dust from the hole wall, blow away the residue, and wipe the hole wall to obtain the rebar holes. Before the hole positioning, scan the original tie bars and rebars in the masonry parapet wall 1 and ring beam 3, and avoid the original tie bars and rebars when positioning the holes. In the scanning, take 8 evenly distributed measuring points for one masonry parapet wall 1. The hole positioning is combined with a laser level and chalk line. The drilling is done with a dry water drill. The diameter of the rebar holes is 4mm larger than the diameter of the prestressed tendon 2. The floating dust on the hole wall is brushed off repeatedly with a long-handled steel brush. The residue is blown away with a high-pressure blower or air compressor. The hole wall is wiped with alcohol cotton balls. Step 3: Inject anchoring adhesive into the anchoring holes obtained in Step 2 from the bottom up, then slowly screw the prestressed tendon 2 into the anchoring hole, and then cure it to obtain the pre-anchored masonry parapet wall; the prestressed tendon 2 is a pre-cleaned threaded steel bar, and the curing temperature is room temperature and the time is not less than 24 hours. Step 4: Grind around the anchoring holes on the top surface of the pre-reinforced masonry parapet wall obtained in Step 3, then lay the lining layer 4, and then fit the prestressed tendon 2 with a rectangular steel plate 5 with holes, and screw in the anchoring nut 6 to obtain a masonry parapet wall with anchors; the grinding is carried out using an angle grinder, the lining layer 4 is a rubber pad with a thickness of 3mm, the rectangular steel plate 5 has a thickness of 14mm, the side length is 80% of the thickness of the masonry parapet wall 1, and the diameter of the opening of the rectangular steel plate 5 is 4mm larger than the diameter of the prestressed tendon 2; Step 5: Using a hydraulic jack and pressure gauge, tension the anchorages in the masonry parapet wall with anchorages from Step 4. The tensioning process is as follows: First, perform initial tensioning by applying 5% of the design tension force of the prestress. Use a hydraulic jack to tension the exposed end of the prestressing tendon 2 and tighten the anchor nut 6 to ensure that the rectangular steel plate 5, the lining 4, and the anchor nut 6 are tightly fitted. After the initial tensioning load is held stable for 2 minutes, perform graded loading, i.e., perform graded loading at 25%, 55%, and 100% of the design tension force of the prestress. After holding the load for 5 minutes, and confirming that there is no slippage or pressure drop, tighten the anchor nut 6 to lock it in place. Step Six: After the tensioning in Step Five is completed, cut off the prestressing tendon 2 that is exposed to the anchor nut 6, then apply epoxy zinc-rich anti-corrosion paint to the anchor, fill the circumferential gap between the rectangular steel plate 5 and the prestressing tendon 2 with grout, and encapsulate the anchor with polymer cement mortar to complete the construction of the internal vertical prestressing tendon reinforced masonry parapet wall.

[0035] In this embodiment, the liner 4 may also be a rubber pad with a thickness of 5mm or a rubber pad with a thickness of 5mm.

[0036] Example 3 The height of the masonry parapet wall 1 in this embodiment h It is 800mm wide. b It is 240mm long. L The ring beam is 18000mm long. The concrete used for ring beam 3 is C20 strength. The masonry parapet wall 1 uses ordinary bricks with a strength of MU10, M5 mortar, and Class A adhesive for the rebar. The design bond strength is [value missing]. f bd Take 2.3 MPa.

[0037] This embodiment includes the following steps: Step 1: Design the parameters of the prestressed tendons 2 based on the parameters of the masonry parapet wall 1, including dimensions, quantity, spacing, anchorage length, and design prestressing tension, and verify the reinforcement effect; the prestressed tendons 2 are PSB830 prestressed fine-rolled threaded steel bars, and the diameter of the prestressed tendons 2 is... d The length is 25mm, the depth of the anchor hole plus the thickness of the rectangular steel plate 5 and the height of the anchor nut 6 plus 30mm, the horizontal spacing of the prestressing tendons 2 is 1200mm, and the number is 15. The anchorage length inside the ring beam 3 is... l a It is 220mm; The design value of the anchorage pull-out bearing capacity of the prestressed tendon 2 anchored into the ring beam 3 is verified as follows:

[0038] in, F This is the design tension force for prestressing, expressed in N. N bd This is the design value of the anchorage pull-out bearing capacity, in N. or For safety reasons, d This refers to the diameter of prestressing tendon 2, in mm. l a Anchorage length, in mm. f bd This is the design value for the bonding strength of the rebar adhesive, in N / mm². 2 ; During verification, or Take 0.7, d It is 25mm. l a It is 220mm. f bd It is 2.3 MPa, calculated as follows N bd The design tension of the prestress is 27.8 kN. F The value is 27.8 kN; The local compressive bearing capacity of masonry parapet wall 1 is checked, as follows: ; in, N l This is the design value of the axial force under local compression of prestressed tendon 2, in N. c The coefficient for increasing the local compressive strength of the masonry parapet wall 1. f This is the design value of the compressive strength of the masonry parapet wall 1, in N / mm². 2 , A l The area under partial compression of the masonry parapet wall 1 is shown in mm. 2 ; During verification, c Take 2.0, f It is 1.50 MPa. A l 220mm × 220mm = 48400mm 2 Calculation N l The local pressure of prestressing tendon 2 is 145.2 kN. F =27.8kN, therefore the requirement is met; The stress of prestressed tendon 2 is checked as follows: ; ; in, F n The maximum prestressing force applied to prestressing tendon 2, in N. s con This represents the maximum prestress of prestressing tendon 2, in N / mm². 2 , A s This is the cross-sectional area of ​​prestressing tendon 2, in mm. 2 , f pyk This is the standard value of the yield strength of prestressed tendon 2, in N / mm². 2 ; During verification, f pyk It is 830 MPa, calculated as follows s con It is 705.5 MPa. A s 490.87mm 2 Calculation F n It is 346.3 kN, as calculated above. F The value is 27.8kN, which meets the requirements, and prestressing tendon 2 is at a low prestress level; The average compressive stress of the horizontal section was checked, and the effect of prestressing tendons on improving the shear bearing capacity of the masonry parapet wall 1 was calculated, as follows: ; in, s t The total prestress applied to prestressing tendon 2, in N / mm². 2 , n The number of prestressing tendons 2, F This is the design tension force for prestressing, expressed in N. b The width of the masonry parapet wall 1 is in mm. LThe length of the masonry parapet wall 1 is in mm. f This is the design value of the compressive strength of the masonry parapet wall 1, in N / mm². 2 ; During verification, F It is 27.8kN. b It is 240mm. L It is 18000mm. f It is 1.50 MPa, calculated as follows s t It is 0.10 MPa, less than 0.8. f= 1.2MPa, therefore the requirement is met; ; in, V This is the design value of the horizontal section shear capacity of the reinforced masonry parapet wall 1, in N. f v This is the design value of the shear strength of the masonry, in N / mm². 2 , α Correction coefficient ,m The influence coefficient of combined shear and compression forces ,s 0 represents the average compressive stress in the horizontal section, in MPa. A The horizontal cross-sectional area of ​​the masonry parapet wall 1 is given in mm². 2 ; During verification, f v It is 0.11 MPa. α Take 0.60, m Take 0.24, A 4320000mm 2 Before reinforcement, only the self-weight of the masonry parapet wall 1 was considered. s 0 is 0.014 MPa, after reinforcement s With a strength of 0.114 MPa, the shear bearing capacity of the unreinforced masonry parapet wall 1 was calculated to be 483.9 kN, and the shear bearing capacity of the reinforced masonry parapet wall 1 was 546.1 kN, representing a theoretical increase of approximately 12.9% in shear bearing capacity. Step 2: Based on the prestressing tendon 2 parameters designed in Step 1, make equally spaced holes on the top surface of the masonry parapet wall 1. Then, drill vertically downwards from the top of the masonry parapet wall 1, penetrating the masonry parapet wall 1 and reaching the bottom ring beam 3. Afterwards, brush off the floating dust from the hole wall, blow away the residue, and wipe the hole wall to obtain the rebar holes. Before the hole positioning, scan the existing tie bars and rebars in the masonry parapet wall 1 and ring beam 3, and avoid the existing tie bars and rebars when positioning the holes. In the scanning, take 8 evenly distributed measuring points for one masonry parapet wall 1. The hole positioning is combined with a laser level and chalk line. The drilling is done with a dry water drill. The diameter of the rebar holes is 8mm larger than the diameter of the prestressing tendon 2. The floating dust on the hole wall is brushed off repeatedly with a long-handled steel brush. The residue is blown away with a high-pressure blower or air compressor. The hole wall is wiped with alcohol cotton balls. Step 3: Inject anchoring adhesive into the anchoring holes obtained in Step 2 from the bottom up, then slowly screw the prestressed tendon 2 into the anchoring hole, and then cure it to obtain the pre-anchored masonry parapet wall; the prestressed tendon 2 is a pre-cleaned threaded steel bar, and the curing temperature is room temperature and the time is not less than 24 hours. Step 4: Grind around the anchoring holes on the top surface of the pre-reinforced masonry parapet wall obtained in Step 3, then lay the lining layer 4, and then fit the pre-stressed tendons 2 with a rectangular steel plate 5 with holes, and screw in the anchoring nuts 6 to obtain a masonry parapet wall with anchors; the grinding is carried out using an angle grinder, the lining layer 4 is a 7mm thick epoxy mortar leveling layer, the rectangular steel plate 5 is 10mm thick, the side length is 90% of the thickness of the masonry parapet wall 1, and the diameter of the opening of the rectangular steel plate 5 is 8mm larger than the diameter of the pre-stressed tendons 2; Step 5: Using a hydraulic jack and pressure gauge, tension the anchorages in the masonry parapet wall with anchorages from Step 4. The tensioning process is as follows: First, perform initial tensioning by applying 15% of the design tension force of the prestress. Use a hydraulic jack to tension the exposed end of the prestressing tendon 2 and tighten the anchor nut 6 to ensure that the rectangular steel plate 5, the lining 4, and the anchor nut 6 are tightly fitted. After the initial tensioning load is held stable for 1 minute, perform graded loading, i.e., perform graded loading according to 35%, 65%, and 100% of the design tension force of the prestress. After holding the load for 5 minutes, and confirming that there is no slippage or pressure drop, tighten the anchor nut 6 to lock it. Step Six: After the tensioning in Step Five is completed, cut off the prestressing tendon 2 that is exposed to the anchor nut 6, then apply epoxy zinc-rich anti-corrosion paint to the anchor, fill the circumferential gap between the rectangular steel plate 5 and the prestressing tendon 2 with grout, and encapsulate the anchor with polymer cement mortar to complete the construction of the internal vertical prestressing tendon reinforced masonry parapet wall.

[0039] In this embodiment, the lining layer 4 may also be an epoxy mortar leveling layer with a thickness of 5 mm or an epoxy mortar leveling layer with a thickness of 10 mm.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A construction method for reinforcing masonry parapet walls with internal vertical prestressed tendons, characterized in that, This method involves vertically installing prestressed tendons within the masonry parapet wall, anchoring the prestressed tendons at the bottom of the ring beam using structural adhesive, and then applying prestress to the prestressed tendons to reinforce the masonry parapet wall. The specific steps include: Step 1: Design the parameters of the prestressing tendons based on the parameters of the masonry parapet wall, including the size, quantity, spacing, anchorage length, and design tension of the prestressing, and verify the reinforcement effect. Step 2: According to the prestressed tendon parameters designed in Step 1, make equally spaced holes on the top surface of the masonry parapet wall. Then, drill vertically downwards from the top of the masonry parapet wall, and the depth should penetrate the masonry parapet wall and enter the bottom ring beam. After that, brush off the floating dust on the hole wall, blow away the residue, wipe the hole wall, and obtain the rebar hole. Step 3: Inject anchoring adhesive into the anchoring holes obtained in Step 2 from the bottom up, then slowly screw the prestressed tendons into the anchoring holes, and then cure them to obtain the pre-anchored masonry parapet wall. Step 4: Grind around the anchor holes on the top surface of the pre-reinforced masonry parapet wall obtained in Step 3, then lay the lining, and then fit the pre-stressed tendons with a rectangular steel plate with holes and screw in the anchor nuts to obtain a masonry parapet wall with anchors. Step 5: Use a hydraulic jack and a pressure gauge to tension the anchorages in the masonry parapet wall with anchorages from Step 4; Step Six: After the tensioning in Step Five is completed, cut off the prestressing tendons that expose the anchor nuts, then apply epoxy zinc-rich anti-corrosion paint to the anchor, fill the circumferential gap between the rectangular steel plate and the prestressing tendons with grout, and encapsulate the anchor with polymer cement mortar to complete the construction of the internal vertical prestressing tendon reinforcement masonry parapet wall.

2. The construction method for a masonry parapet wall reinforced with internal vertical prestressing tendons according to claim 1, characterized in that, The prestressing tendons mentioned in step one are precision-rolled threaded steel bars with a diameter of 15mm to 25mm and a length equal to the depth of the anchor hole plus the thickness of the rectangular steel plate and the height of the anchor nut plus 10mm to 30mm. The spacing of the prestressing tendons along the length of the masonry parapet wall is 500mm to 1200mm. The number of prestressing tendons is the length of the masonry parapet wall divided by the spacing of the prestressing tendons along the length of the masonry parapet wall. The anchorage length of the prestressing tendons in the ring beam is 160mm to 220mm.

3. The construction method for a masonry parapet wall reinforced with internal vertical prestressing tendons according to claim 1, characterized in that, The verification of the reinforcement effect in step one includes the following process: The design value of the anchorage pull-out bearing capacity of the prestressed tendons at the bottom of the ring beam is verified as follows: in, F This is the design tension force for prestressing, expressed in N. N bd This is the design value of the anchorage pull-out bearing capacity, in N. η For safety reasons, d This refers to the diameter of the prestressing tendon, in mm. l a Anchorage length, in mm. f bd This is the design value for the bonding strength of the rebar adhesive, in N / mm². 2 ; The local compressive bearing capacity of the masonry parapet wall is checked, as follows: ； in, N l This is the design value of the axial force under localized compression of the prestressed tendon, in N. γ This is the coefficient for increasing the local compressive strength of the masonry parapet wall. f This is the design value of the compressive strength of the masonry parapet wall, in N / mm². 2 , A l This represents the localized compressive area of ​​the masonry parapet wall, in mm. 2 ; The stress of the prestressing tendons is checked, as follows: ； ； in, F n The maximum prestressing force applied to the prestressing tendons, expressed in N. σ con This represents the maximum prestressing stress of the prestressing tendon, expressed in N / mm². 2 , A s This represents the cross-sectional area of ​​the prestressing tendons, in mm². 2 , f pyk This is the standard value of the yield strength of prestressed tendons, in N / mm². 2 ; The average compressive stress of the horizontal section was checked, and the effect of prestressing tendons on improving the shear bearing capacity of the masonry parapet wall was calculated, as follows: ； in, σ t The total prestress applied to the prestressing tendons, expressed in N / mm². 2 , n The number of prestressing tendons, F This is the design tension force for prestressing, expressed in N. b This refers to the width of the masonry parapet wall, in mm. L This refers to the length of the masonry parapet wall, in mm. f This is the design value of the compressive strength of the masonry parapet wall, in N / mm². 2 ; ； in, V This is the design value of the horizontal section shear capacity of the reinforced masonry parapet wall, in N. f v This is the design value of the shear strength of the masonry, in N / mm². 2 , α Correction coefficient μ The influence coefficient of combined shear and compression forces , σ 0 represents the average compressive stress in the horizontal section, with units of MPa. A This refers to the horizontal cross-sectional area of ​​the masonry parapet wall, in mm². 2 .

4. The construction method for a masonry parapet wall reinforced with internal vertical prestressing tendons according to claim 1, characterized in that, Before the hole positioning in step two, the existing tie bars and reinforcing bars in the masonry parapet wall and ring beam are scanned, and the existing tie bars and reinforcing bars are avoided when positioning the holes; in the scanning, at least 6 evenly distributed measuring points are taken for each masonry parapet wall.

5. The construction method for a masonry parapet wall reinforced with internal vertical prestressing tendons according to claim 1, characterized in that, In step two, the hole positioning is combined with a laser level and chalk line marking. The drilling is done with a dry water drill. The diameter of the anchor hole is 4mm to 8mm larger than the diameter of the prestressing tendon. The floating dust on the hole wall is repeatedly brushed off with a long-handled steel brush. The residue is blown off with a high-pressure blower or air compressor. The hole wall is wiped with alcohol cotton balls.

6. The construction method for a masonry parapet wall reinforced with internal vertical prestressing tendons according to claim 1, characterized in that, The prestressing tendons mentioned in step three are pre-cleaned threaded steel bars, and the curing temperature is room temperature for no less than 24 hours.

7. The construction method for a masonry parapet wall reinforced with internal vertical prestressing tendons according to claim 1, characterized in that, The grinding in step four is carried out using an angle grinder. The lining is an epoxy mortar leveling layer with a thickness of 5mm to 10mm or a rubber pad with a thickness of 3mm to 5mm. The thickness of the rectangular steel plate is not less than 10mm, and the side length is 80% to 90% of the thickness of the masonry parapet wall. The diameter of the opening in the rectangular steel plate is 4mm to 8mm larger than the diameter of the prestressing tendon.

8. The construction method for a masonry parapet wall reinforced with internal vertical prestressing tendons according to claim 1, characterized in that, The tensioning process described in step five is as follows: First, initial tensioning is performed by applying 5% to 15% of the design tension force of the prestress. A hydraulic jack is used to tension the exposed end of the prestressing tendon, and the anchor nuts are tightened to ensure that the rectangular steel plate, the lining, and the anchor nuts fit tightly together. After the initial tensioning load is held stable for 1 to 2 minutes, staged loading is performed, that is, staged loading is performed at 25% to 35%, 55% to 65%, and 100% of the design tension force of the prestress. After holding the load for 5 minutes, and after confirming that there is no slippage or pressure drop, the anchor nuts are tightened to lock them.

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