A prefabricated UHPC bridge guardrail permanent formwork and construction method thereof

Abstract

The present invention relates to the technical field of bridge guardrails, and proposes a prefabricated UHPC bridge guardrail permanent formwork and a construction method thereof. The permanent formwork comprises a first and a second formwork, a bidirectional tension bolt and a tension screw rod, a bolt hole protrusion and a positioning protrusion are respectively provided at the top and the bottom of the first formwork, a first bolt hole is provided on the bolt hole protrusion, a second bolt hole is provided on the positioning protrusion, a first longitudinal connection hole is provided at both ends of the first formwork, a third bolt hole is provided at the top of the second formwork, a fourth bolt hole is provided at the bottom thereof, a second longitudinal connection hole is provided at both ends thereof, an anchor connection hole is provided at the bottom thereof, supporting steel bars are provided in the middle of the first and second formworks, and the first and second formworks are formed by UHPC; two studs of the bidirectional tension bolts are respectively connected to the first and third bolt holes, and the two ends of the tension screw rod are respectively connected to the second and fourth bolt holes. The present invention solves the problems of slow turnover, long construction period, and high cost of existing guardrails, and improves the quality of the guardrails as well as the convenience and reliability of construction.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge guardrails, and in particular to a prefabricated UHPC bridge guardrail permanent formwork and a construction method thereof. Background Art

[0002] Bridge guardrails refer to guardrails installed on bridges. Their purpose is to prevent out-of-control vehicles from running over the bridge. They have the functions of preventing vehicles from breaking through, passing under, or climbing over the bridge and beautifying the bridge structure. Current bridge guardrails have the following defects: (1) The current construction of bridge concrete guardrails mostly adopts the method of on-site casting. During the casting process, the steel formwork turnover is slow, the construction period is long, and the cost is high;

[0003] (2) The casting quality of cast-in-place guardrails varies, and the construction period is often rushed, which can easily lead to appearance quality problems, such as leakage, pockmarked surfaces, many voids and bubbles, color differences, uneven lines, and surface cracks.

[0004] (3) Cast-in-place guardrails are mostly made of ordinary concrete, which has poor material durability. In particular, a large amount of snow-melting agents are used during bridge maintenance in winter, which can easily cause guardrails to peel off, rust and other defects. At the same time, during the construction of the guardrail, the entire height of the inner collision surface needs to be treated with octyl or isobutyl silane materials for hydrophobic treatment, which increases the cost of the guardrail.

[0005] (4) At present, most prefabricated concrete guardrails are prefabricated as a whole with a length of 4 to 6 meters. They are connected vertically by grouting or bolts, which may cause difficulties in lifting and transportation, poor connection effect, and uneven linear shape.

[0006] Therefore, in order to improve the performance of bridge guardrails and the convenience of installation, a prefabricated UHPC bridge guardrail permanent formwork and a construction method thereof are urgently needed. Summary of the invention

[0007] In order to solve the problems existing in the background technology, the present invention proposes a prefabricated UHPC bridge guardrail permanent formwork, including a first formwork, a second formwork, a bidirectional tension bolt and a tension screw, a bolt hole protrusion is arranged on the inner side of the top of the first formwork along the length direction, a plurality of first bolt holes are arranged on the bolt hole protrusion along the length direction, a positioning protrusion is arranged on the inner side of the bottom of the first formwork along the length direction, a plurality of second bolt holes are arranged on the positioning protrusion along the length direction, first longitudinal connecting holes are arranged on the inner side of both ends of the first formwork, a plurality of third bolt holes are arranged on the inner side of the top of the second formwork along the length direction, a plurality of fourth bolt holes are arranged on the bottom of the second formwork along the length direction, second longitudinal connecting holes are arranged on the inner side of both ends of the second formwork, anchoring connecting holes are arranged at both ends and the middle position of the inner side of the bottom of the second formwork, and the anchoring connecting holes are located below the second longitudinal connecting holes and the fourth bolt holes, a plurality of supporting steel bars are fixed on the inner side of the middle parts of the first formwork and the second formwork along the length direction, and the first formwork and the second formwork are both formed of UHPC material;

[0008] The two studs of the bidirectional tensioning bolt are respectively connected to the first bolt hole and the third bolt hole, and the two ends of the tensioning screw rod are respectively connected to the second bolt hole and the fourth bolt hole.

[0009] Preferably, a dripping eave is provided at the bottom end of the first template, and the dripping eave is integrally formed with the first template.

[0010] Preferably, a first UHPC liner is provided on the inner side of one end of the first template, and one end of the first UHPC liner extends out of the first template; a second UHPC liner is provided on the inner side of one end of the second template, and one end of the second UHPC liner extends out of the second template, and the positions of the first UHPC liner and the second UHPC liner correspond.

[0011] Preferably, the third bolt hole comprises a reserved groove, a nut track and a slide groove nut, the reserved groove is opened on the second template, the nut track is fixed in the reserved groove, the slide groove nut is slidably arranged on the nut track, and a screw rod of the bidirectional tensioning bolt is threadedly connected with the slide groove nut;

[0012] The fourth bolt hole is a long through hole, one end of the tension screw is threadedly connected to the second bolt hole, the other end of the tension screw passes through the fourth bolt hole and is located outside the second template, and one end of the tension screw located outside the second template is provided with a gasket and threadedly connected with a nut.

[0013] Preferably, the UHPC components used to make the first template and the second template include 45% to 53% by mass of a cementitious system, 7.2% to 8.7% by mass of water, 43.75% to 48.4% by mass of fine aggregate, 1% to 1.62% by mass of organic fiber, and 0.82% to 1.2% by mass of an admixture;

[0014] The water-cement ratio is 0.16~0.18, the sand-cement ratio is 0.82~1.02, the amount of admixture is 1.7%~2.3% of the cementitious material, and the fiber volume content is 1.8%~2.7%.

[0015] Preferably, the cementitious system comprises 60% to 70% by weight of cement, 5% to 15% by weight of fly ash, 10% to 15% by weight of microsilica fume, and 15% to 25% by weight of slag.

[0016] Preferably, the cement is slag cement or ordinary Portland cement with a grade greater than or equal to 42.5, the fly ash is ultrafine fly ash, the fine aggregate is river sand or quartz sand or recycled fine aggregate, the admixture is a polycarboxylic acid-based high-efficiency water reducer and a superdispersant, or a superplasticizer and a defoaming agent, and the organic fiber is an ultra-high molecular weight polyethylene fiber with a diameter of 20 μm and a length of 12 mm.

[0017] A construction method for prefabricating a permanent formwork for a UHPC bridge guardrail comprises the following steps:

[0018] S1, prefabricate the first formwork and the second formwork: when prefabricate the first formwork, preset the first bolt hole, the second bolt hole and the first longitudinal connection hole, and pre-embed the supporting steel bars; when prefabricate the second formwork, preset the third bolt hole, the fourth bolt hole, the second longitudinal connection hole and the anchor connection hole, and pre-embed the supporting steel bars; perform roughening treatment on the inner sides of the first formwork and the second formwork respectively, and the roughening treatment is completed before the initial setting of the formwork;

[0019] S2, transporting the prefabricated first template and second template to the construction site;

[0020] S3. Position and lay out the anti-collision guardrail and determine the installation position of the guardrail;

[0021] S4. Roughen the base surface of the guardrail installation location;

[0022] S5. Tie guardrail steel bars, where the guardrail steel bars are located between the first formwork and the second formwork installation positions;

[0023] S6. Preplant anchor steel bars and adjust the anchor steel bars;

[0024] S7, hoisting the first template to the installation position, screwing a stud of the two-way tension bolt into the first bolt hole at the top of the first template, and applying epoxy resin anchor glue or concrete structural glue to the bottom of the positioning protrusion;

[0025] The second template is hoisted to the installation position, and the anchor steel bar is passed through the anchor connection hole at the bottom of the second template. The anchor connection hole is a truncated cone shape with a wide top and a narrow bottom. After the anchor steel bar passes through the anchor connection hole, epoxy resin anchor glue or concrete structural glue is injected into the anchor connection hole to fix the anchor steel bar to the second template; another stud of the two-way tensioning bolt is screwed into the slide nut at the top of the second template; one end of the tension screw is passed through the fourth bolt hole at the bottom of the second template and connected to the second bolt hole of the first template;

[0026] S8. Use the lead screw of the bidirectional tension bolt to connect the studs at the top of the first and second templates; put a gasket on the end of the tension screw extending out of the second template, and then thread the nut to tighten the tension screw through the gasket and the nut;

[0027] A fixture is placed on the top of the first template and the second template, and the distance between the first template and the second template is determined by the fixture; the lead screw is turned, and the lead screw drives the two studs to move, thereby tightening or loosening the first template and the second template; the nut is turned, and the first template and the second template are loosened or tightened by changing the position of the nut on the tension screw;

[0028] S9, applying epoxy resin anchoring glue on the outer side surfaces and end UHPC liner plates of the first and second templates, and then installing the next first template and the next second template according to step S7, connecting two adjacent second templates by passing a longitudinal bolt through the second longitudinal connection holes on the two second templates; then connecting two adjacent first templates by passing another longitudinal bolt through the first longitudinal connection holes on the two first templates, and finally connecting the newly installed first template and the second template according to step S8;

[0029] S10, connecting the remaining first formwork and the second formwork in sequence according to step S9, and pouring concrete between the first formwork and the second formwork, and filling the fourth bolt hole with foam glue before pouring concrete.

[0030] Preferably, the step S6 specifically includes: pre-planting anchoring steel bars and adjusting the anchoring steel bars; and setting temporary anchoring points on the bridge deck;

[0031] Step S81: After completing step S8, use steel wires and bidirectional tension bolts to temporarily support the first and second templates, one end of the steel wire is temporarily connected to the bidirectional tension bolts on the top of the template, and the other end of the steel wire is connected to the temporary anchor point of the bridge face;

[0032] The step S9 specifically includes: after the newly installed first formwork and the second formwork are connected according to the step S8, the newly installed first formwork and the second formwork are temporarily supported according to the step S81.

[0033] Preferably, step S7 specifically comprises: hoisting the first template to the installation position, adjusting the position of the first template, spot welding the support steel bar to the guardrail steel bar, screwing a stud of the bidirectional tensioning bolt into the first bolt hole at the top of the first template, and applying epoxy resin anchor glue or concrete structural glue to the bottom of the positioning protrusion;

[0034] Lift the second formwork to the installation position, and pass the anchor steel bar through the anchor connection hole at the bottom of the second formwork. The anchor connection hole is a cone-shaped hole that is wide at the top and narrow at the bottom. The minimum hole diameter of the anchor connection hole is larger than the diameter of the anchor steel bar. After the anchor steel bar passes through the anchor connection hole, inject epoxy resin anchor glue or concrete structural glue into the anchor connection hole to fix the anchor steel bar to the second formwork; screw the other stud of the two-way tensioning bolt into the slide nut at the top of the second formwork; pass one end of the tension screw through the fourth bolt hole at the bottom of the second formwork and connect it to the second bolt hole of the first formwork.

[0035] Preferably, the method for hoisting the first template and the second template is:

[0036] Lifting the first template: install a lifting ring in the first bolt hole, pass the lifting belt through the lifting ring, and connect the first template and the lifting equipment through the lifting belt. There should be no less than two lifting points and they should be arranged symmetrically;

[0037] Lifting the second template: pass the lifting belt through the fourth bolt hole, connect the second template and the lifting equipment through the lifting belt, and there should be no less than two lifting points and they should be arranged symmetrically;

[0038] After the first formwork and the second formwork are connected, remove the lifting ring.

[0039] The present invention has the following beneficial effects:

[0040] (1) The first and second formworks are made of UHPC material, which has the characteristics of high strength, high toughness and high durability. The first and second formworks can become permanent formworks of the guardrail. At the same time, after the two formworks are installed, they are cast into a whole by ordinary concrete, which significantly improves the impact resistance and durability of the anti-collision guardrail, and effectively solves the durability problems of the guardrail caused by snow melting agents and freezing. In the long run, over the entire life cycle of the guardrail, this structure can effectively reduce the frequency of guardrail maintenance and achieve the purpose of long-term operation cost reduction;

[0041] (2) The use of UHPC prefabricated guardrail formwork solves the problem of slow turnover of steel formwork and long construction period;

[0042] (3) The UHPC formwork has the characteristics of high toughness and high rigidity. At the same time, it is connected by bidirectional tension bolts and tension screws, which improves the overall rigidity and avoids the problem of mold running during pouring;

[0043] (4) The first and second formworks are prefabricated in the factory, which can ensure that the color of the formwork surface is uniform and consistent, avoiding appearance quality problems and concrete pouring problems caused by rushing the construction schedule on site;

[0044] (5) The first formwork and the second formwork can be installed at multiple points at the same time, and after the formwork is installed, concrete can be poured between the two formworks at multiple points at the same time, which greatly shortens the construction period; the formwork is light in weight, easy to carry and install, and improves the convenience of construction;

[0045] (6) The horizontal connection is made through bidirectional tension bolts and tension screws; the vertical connection is made through bridge deck embedded reinforcement; the longitudinal connection is made through longitudinal bolts. Multiple connection methods work together to ensure the stability of the formwork structure;

[0046] (7) UHPC material has a compact structure and low permeability coefficient, which can significantly reduce the internal water loss of cast-in-place concrete and fully ensure the strength of concrete;

[0047] (8) The guardrail template is 1 to 2 meters long, which can better replace curves with straight lines to ensure a smoother line shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the side structure of the present invention;

[0049] Figure 2 It is a schematic diagram of the cross-sectional structure of the present invention;

[0050] Figure 3 This is a schematic diagram of the inner structure of the first template of the present invention;

[0051] Figure 4 This is a schematic diagram of the side structure of the first template of the present invention;

[0052] Figure 5 This is a schematic diagram of the inner structure of the second template of the present invention;

[0053] Figure 6 It is a schematic diagram of the side structure of the second template of the present invention;

[0054] Figure 7 This is a schematic diagram of the bidirectional tension bolt structure of the present invention;

[0055] Figure 8 This is a schematic diagram of the supporting steel bars and the steel bars built into the template of the present invention.

[0056] Numbers in the figure: 1. first formwork; 2. second formwork; 3. first bolt hole; 4. second bolt hole; 5. third bolt hole; 6. fourth bolt hole; 7. first longitudinal connection hole; 8. second longitudinal connection hole; 9. anchor connection hole; 10. bidirectional tensioning bolt; 101. lead screw; 102. stud; 11. tensioning screw; 12. supporting steel bar; 13. built-in steel bar; 14. first UHPC liner; 15. second UHPC liner; 16. bolt hole boss; 17. positioning boss; 18. drip eaves. DETAILED DESCRIPTION

[0057] In order to make the present invention clearer and more understandable, the technical solution of the present invention is further described in detail below in combination with the accompanying drawings and embodiments. It should be understood that the given embodiment is only one of the implementation methods and does not represent all embodiments.

[0058] In this article, the terms "upper, lower, inside, outside" and the like are established based on the positional relationships shown in the drawings. Depending on the different drawings, the corresponding positional relationships may also change accordingly. Therefore, they cannot be understood as absolute limitations on the scope of protection.

[0059] Combined with Figure 1 -Attached Figure 8 A prefabricated UHPC bridge guardrail permanent formwork, comprising a first formwork 1, a second formwork 2, a bidirectional tension bolt 10 and a tension screw 11, a plurality of first bolt holes 3 are arranged on the inner side of the top of the first formwork 1 along the length direction, a positioning protrusion 17 is arranged on the inner side of the bottom of the first formwork 1 along the length direction, a plurality of second bolt holes 4 are arranged on the positioning protrusion 17 along the length direction, first longitudinal connecting holes 7 are arranged on the inner sides of both ends of the first formwork 1, the longitudinal direction is the length direction of the formwork, a dripping eave 18 is arranged at the bottom end of the first formwork 1, and the dripping eave 18 is integrally formed with the first formwork 1; specifically, two first longitudinal connecting holes 7 are arranged at each end of the first formwork 1, and the two first longitudinal connecting holes 7 are respectively located near the top of the first formwork 1 and near the bottom of the first formwork 1;

[0060] A plurality of third bolt holes 5 are arranged on the inner side of the top of the second template 2 along the length direction, and the third bolt holes 5 include a reserved groove, a nut track and a slide nut, the reserved groove is opened on the second template 2, the nut track is fixed in the reserved groove, and the slide nut is slidably arranged on the nut track; a plurality of fourth bolt holes 6 are arranged on the bottom of the second template 2 along the length direction, and the fourth bolt holes 6 are long through holes, second longitudinal connecting holes 8 are arranged on the inner sides of both ends of the second template 2, and anchoring connecting holes 9 are arranged at both ends and the middle position of the inner side of the bottom of the second template 2, and the anchoring connecting holes 9 are located below the second longitudinal connecting holes 8 and the fourth bolt holes 6; specifically, two second longitudinal connecting holes 8 are arranged at each of the two ends of the second template 2, and the two second longitudinal connecting holes 8 are respectively located near the top of the second template 2 and near the bottom of the second template 2;

[0061] The two-way tensioning bolt 10 includes two studs 102 and a lead screw 101, each of the two ends of the lead screw 101 is provided with a threaded hole, and a through hole is provided in the middle part of the lead screw 101, which is connected to the two threaded holes, and the through hole is used to provide a moving space for the stud 102, and the two studs 102 are respectively threadedly connected to the threaded holes at both ends of the lead screw 101; the two studs 102 of the two-way tensioning bolt 10 are respectively connected to the first bolt hole 3 and the third bolt hole 5, specifically, one screw of the two-way tensioning bolt 10 is threadedly connected to the slide nut, and the other screw of the two-way tensioning bolt 10 is connected to the first bolt hole 3; the two ends of the tensioning screw 11 are respectively connected to the second bolt hole 4 and the fourth bolt hole 6, specifically, one end of the tensioning screw 11 is threadedly connected to the second bolt hole 4, and the other end of the tensioning screw 11 passes through the fourth bolt hole 6 and is located on the outside of the second template 2, and the end of the tensioning screw 11 located on the outside of the second template 2 is sleeved with a gasket and threadedly connected with a nut;

[0062] The positions and quantities of the first bolt hole 3 and the third bolt hole 5 correspond, and the positions and quantities of the second bolt hole 4 and the fourth bolt hole 6 correspond; specifically, the number of the two-way tensioning bolts 10 is at least three, and the three two-way tensioning bolts 10 are respectively located at the two ends and the middle position in the length direction of the first template 1; the number of the tensioning screws 11 is at least three, and the three tensioning screws 11 are respectively located at the two ends and the middle position in the length direction of the first template 1; the number of the first bolt hole 3, the third bolt hole 5, the second bolt hole 4 and the fourth bolt hole 6 are not less than three, so that when the first template 1 and the second template 2 are dislocated in relative position, the transverse connection can still be guaranteed.

[0063] A plurality of supporting steel bars 12 are fixed along the length direction at the middle inner positions of the first formwork 1 and the second formwork 2. The first formwork 1 and the second formwork 2 are both formed of UHPC (ultra-high performance concrete) materials; a first UHPC liner 14 is provided on the inner side of one end of the first formwork 1, and one end of the first UHPC liner 14 extends outside the first formwork 1; a second UHPC liner 15 is provided on the inner side of one end of the second formwork 2, and one end of the second UHPC liner 15 extends outside the second formwork 2; the first UHPC liner 14 and the second UHPC liner 15 are located in corresponding positions; the first UHPC liner 14 is used to connect two adjacent first formworks 1, and the second UHPC liner 15 is used to connect two adjacent second formworks 2, so as to prevent leakage of concrete during internal concrete pouring. Specifically, a bolt hole protrusion 16 is provided on the inner side of the top of the first formwork 1 along the length direction, and the first bolt hole 3 is provided on the bolt hole protrusion 16.

[0064] Specifically, the first template 1 is 1m~2m long and 1cm~2cm thick. The first template 1 is preferably 1m long and 1cm thick. The thickness of the preset embedded part is 2cm. The inner side of the first template 1 is roughened. The center point of the first bolt hole 3 is 4cm~5cm away from the top surface of the first template 1. The distance between two adjacent first bolt holes 3 is 20cm~25cm. The diameter of the first bolt hole 3 is 20mm or 22mm. The bolt hole protrusion 16 is arranged through the length. The bolt hole protrusion 16 is 1cm~2cm thick and 4cm~5.5cm high. The first longitudinal connecting hole 7 is located above the positioning protrusion 17, and its hole depth is 3c m~5cm, the hole diameter is 20mm or 22mm, the center of the first longitudinal connecting hole 7 located at the top is 8cm~15cm away from the top surface of the first template 1, and the first longitudinal connecting hole 7 can be formed by stainless steel embedded parts or UHPC casting; the positioning protrusion 17 is arranged throughout the length and is used to support the first template 1 on the bridge deck. The positioning protrusion 17 is 5cm~6cm high and 4cm thick; the second bolt hole 4 is set in the middle of the positioning protrusion 17, the distance between two adjacent second bolt holes 4 is 20cm~25cm, and the diameter of the second bolt hole 4 is 20mm or 22mm; the drip eaves 18 are integrally cast with the first template 1, and the drip eaves 18 are 24 cm~30cm long. The length of the drip eaves 18 can be set according to specific circumstances; the first UHPC liner 14 is 1cm thick and 10cm wide, and the length extending from the first template 1 is 4 cm~6cm;

[0065] The second template 2 is 1m~2m long and 1cm~2cm thick. The second template 2 is preferably 1m long and 1cm thick. The thickness of the preset embedded part is 2cm. The inner side of the second template 2 is roughened. A reserved groove is set at the anti-climbing step. A nut track is fixed in the reserved groove. The center point of the nut track is 3cm~4cm away from the top surface of the second template 2. The center distance between two adjacent nut tracks is 20cm~25cm. The length of the nut track is 3cm~5cm. The second longitudinal connecting hole 8 is 3cm~5cm deep and has a hole diameter of 20mm or 22mm. The center of the second longitudinal connecting hole 8 located at the top is 8cm~15cm away from the top surface of the second template 2. The second longitudinal connecting hole 8 can be formed by stainless steel embedded parts or UHPC casting. The anchoring connecting hole 9 is used to anchor the second template 2 to the bridge deck. The anchoring connecting hole 9 is 3~4cm deep and can be formed by stainless steel embedded parts or UHPC casting. The bottom of the fourth bolt hole 6 is 4 cm away from the bottom edge of the second template 2 ~6cm, the fourth bolt hole 6 is 8cm~10cm long and is used to arrange the tension reinforcement; the second UHPC liner 15 is 1cm thick and 10cm wide, and the length extending from the second template 2 is 4cm~6cm; a false seam is usually set every two meters for cast-in-place guardrails, so the length of the prefabricated first template 1 and the second template 2 is preferably set to 1 meter, so as to overcome the problem of uneven linear shape that often occurs in the integral prefabricated guardrail.

[0066] The diameter of the support steel bar 12 is 6mm, 8mm or 10mm. Specifically, the multiple support steel bars 12 on each template are spot welded to an internal steel bar 13. The internal steel bar 13 is buried in the middle of the template. The internal steel bar 13 is arranged along the length direction of the template. The support steel bar 12 is also buried in a part of the template, and the buried depth is greater than or equal to 1 times the diameter of the support steel bar 12. The support steel bar 12 can be a smooth steel bar or a ribbed steel bar. Specifically, two rows of support steel bars 12 are respectively arranged on the inner side of the first template 1 and the second template 2, and the two rows of support steel bars 12 are arranged along the height direction of the template.

[0067] The tensioning screw rod 11 is 55-58 cm long and has a diameter of 8 mm or 10 mm. The bidirectional tensioning bolt 10 includes two studs 102 and a lead screw 101. The two studs 102 are respectively fixed in the bolt holes reserved at the top of the first template 1 and the second template 2. The lead screw 101 is used to adjust the lateral position of the first template 1 and the second template 2, and at the same time acts as a pull rod to prevent the mold from running when pouring concrete.

[0068] Specifically, the UHPC components used to make the first formwork 1 and the second formwork 2 include 45% to 53% by mass of a cementitious system, 7.2% to 8.7% by mass of water, 43.75% to 48.4% by mass of fine aggregate, 1% to 1.62% by mass of organic fiber, and 0.82% to 1.2% by mass of an admixture; the formwork strength is not less than 90 MPa, the elastic modulus is above 50 GPa, and steam curing or natural curing is adopted, preferably steam curing; since the formwork is cast vertically and has structural requirements such as angles, the fluidity should not be too large and should be controlled between 550 and 600; the use of organic fibers can ensure that the formwork guardrail is smooth and tidy;

[0069] The water-cement ratio is 0.16~0.18, the sand-cement ratio (the ratio of the mass of fine aggregate to the mass of the cementitious system) is 0.82~1.02, the amount of admixture is 1.7%~2.3% of the cementitious material, and the fiber volume content is 1.8%~2.7%.

[0070] Specifically, the cementitious system includes 60% to 70% by weight of cement, 5% to 15% by weight of fly ash, 10% to 15% by weight of microsilica fume, and 15% to 25% by weight of slag.

[0071] Specifically, the cement is preferably slag cement or ordinary Portland cement with a grade greater than or equal to 42.5, and sulfate-resistant cement, alkali-slag cement or ferroaluminate cement may also be used; the fly ash is ultrafine fly ash (microbead fly ash) with an average particle size of 1.2 μm; the fine aggregate is river sand or quartz sand or recycled fine aggregate, and the recycled fine aggregate is processed by a jaw crusher through concrete (including UHPC) with an original strength of C50 and above, and water retention treatment is required when using the recycled fine aggregate; the admixture is a polycarboxylic acid-based high-efficiency water reducer and a superdispersant, or a superplasticizer and a defoaming agent, and the organic fiber is an ultra-high molecular weight polyethylene fiber with a diameter of 20 μm and a length of 12 mm, and polyvinyl alcohol fiber or polyethylene fiber or alkali-resistant glass fiber may also be used, preferably ultra-high molecular weight polyethylene fiber.

[0072] Embodiment 1:

[0073] A construction method for prefabricating a permanent formwork for a UHPC bridge guardrail comprises the following steps:

[0074] S1, prefabricate the first template 1 and the second template 2: when prefabricate the first template 1, preset the first bolt hole 3, the second bolt hole 4 and the first longitudinal connection hole 7, and pre-embed the supporting steel bar 12; when prefabricate the second template 2, preset the third bolt hole 5, the fourth bolt hole 6, the second longitudinal connection hole 8 and the anchor connection hole 9, and pre-embed the supporting steel bar 12; perform roughening treatment on the inner sides of the first template 1 and the second template 2 respectively, and the roughening treatment should be completed before the initial setting of the template, and it can be achieved by roughening, printing patterns, etc.;

[0075] S2, transporting the prefabricated first template 1 and second template 2 to the construction site;

[0076] S3. Position and lay out the anti-collision guardrail and determine the installation position of the guardrail;

[0077] S4. Roughen the base surface of the guardrail installation location;

[0078] S5, tying guardrail steel bars, where the guardrail steel bars are located between the installation positions of the first formwork 1 and the second formwork 2;

[0079] S6. Preplant anchor steel bars and adjust them; at the same time, set temporary anchor points on the bridge deck;

[0080] S7, hoist the first template 1 to the installation position, screw a stud of the two-way tension bolt 10 into the first bolt hole 3 at the top of the first template 1, and apply epoxy resin anchor glue or concrete structural glue to the bottom of the positioning protrusion 17;

[0081] Lift the second formwork 2 to the installation position, apply epoxy resin anchor glue or concrete structure glue at the position where the anchor connection hole 9 is set at the bottom of the second formwork 2; pass the anchor steel bar through the anchor connection hole 9 at the bottom of the second formwork 2, and after the anchor steel bar passes through the anchor connection hole 9, inject epoxy resin anchor glue or concrete structure glue into the anchor connection hole 9 to fix the anchor steel bar to the second formwork 2. Specifically, the anchor connection hole 9 is a truncated cone shape that is wide at the top and narrow at the bottom, which is convenient for injecting epoxy resin anchor glue or concrete structure glue and enhancing the anchoring effect; screw another stud of the two-way tensioning bolt 10 into the slide nut at the top of the second formwork 2; pass one end of the tension screw 11 through the fourth bolt hole 6 passing through the bottom of the second formwork 2 and connect it to the second bolt hole 4 of the first formwork 1;

[0082] S8. Use the lead screw 101 of the two-way tension bolt 10 to connect the studs 102 at the top of the first and second templates, and turn the lead screw 101 of the two-way tension bolt 10. The lead screw 101 pulls the two studs 102, so that the relative position of the first template 1 and the second template 2 can be adjusted; put a gasket on the end of the tension screw 11 extending out of the second template 2, and then thread the nut to tighten the tension screw 11 through the gasket and the nut;

[0083] A fixture is placed on the top of the first template 1 and the second template 2, and the distance between the first template 1 and the second template 2 is determined by the fixture; the lead screw 101 is turned, and the lead screw 101 drives the two studs 102 to move, thereby tightening or loosening the first template 1 and the second template 2; step S81: using a steel wire and a two-way tensioning bolt 10 to temporarily support the first and second templates, one end of the steel wire is temporarily connected to the two-way tensioning bolt 10 on the top of the template, and the other end of the steel wire is connected to the temporary anchor point of the bridge surface;

[0084] S9, apply epoxy resin anchoring glue on the outer side and end UHPC liner of the first template 1 and the second template 2, then install the next first template 1 and the next second template 2 according to step S7, use a longitudinal bolt to pass through the second longitudinal connection hole 8 on the two second templates 2 to connect the two adjacent second templates 2; then use another longitudinal bolt to pass through the first longitudinal connection hole 7 on the two first templates 1 to connect the two adjacent first templates 1, finally connect the newly installed first template 1 and the second template 2 according to step S8, and temporarily anchor the newly installed first template 1 and the second template 2 according to step S81;

[0085] S10, connecting the remaining first formwork 1 and the second formwork 2 in sequence according to step S9, and pouring concrete between the first formwork 1 and the second formwork 2. Before pouring concrete, fill the fourth bolt hole 6 with foam glue to avoid leakage during concrete pouring.

[0086] Specifically, the method for hoisting the first template 1 and the second template 2 is:

[0087] Lifting the first template 1: install a lifting ring in the first bolt hole 3, pass the lifting belt through the lifting ring, and connect the first template 1 and the lifting equipment through the lifting belt. There should be no less than two lifting points and they should be arranged symmetrically;

[0088] Lifting the second template 2: pass the lifting belt through the fourth bolt hole 6, pass the lifting belt through the lifting ring, and connect the second template 2 and the lifting equipment through the lifting belt. There should be no less than two lifting points and they should be arranged symmetrically;

[0089] After the first template 1 and the second template 2 are connected, the lifting ring is removed.

[0090] Embodiment 2:

[0091] A construction method for prefabricating a permanent formwork for a UHPC bridge guardrail comprises the following steps:

[0092] S1, prefabricate the first template 1 and the second template 2: when prefabricate the first template 1, preset the first bolt hole 3, the second bolt hole 4 and the first longitudinal connection hole 7, and pre-embed the supporting steel bar 12; when prefabricate the second template 2, preset the third bolt hole 5, the fourth bolt hole 6, the second longitudinal connection hole 8 and the anchor connection hole 9, and pre-embed the supporting steel bar 12; perform roughening treatment on the inner sides of the first template 1 and the second template 2 respectively, and the roughening treatment should be completed before the initial setting of the template, and it can be achieved by roughening, printing patterns, etc.;

[0093] S2, transporting the prefabricated first template 1 and second template 2 to the construction site;

[0094] S3. Position and lay out the anti-collision guardrail and determine the installation position of the guardrail;

[0095] S4. Roughen the base surface of the guardrail installation location;

[0096] S5, tying guardrail steel bars, where the guardrail steel bars are located between the installation positions of the first formwork 1 and the second formwork 2;

[0097] S6. Preplant anchor steel bars and adjust the anchor steel bars;

[0098] S7, hoist the first template 1 to the installation position, adjust the position of the first template 1, spot weld the support steel bar 12 to the guardrail steel bar, screw a stud of the two-way tension bolt 10 into the first bolt hole 3 at the top of the first template 1, and apply epoxy resin anchor glue or concrete structural glue to the bottom of the positioning protrusion 17;

[0099] The second formwork 2 is hoisted to the installation position, and the anchoring steel bar is passed through the anchoring connection hole 9 at the bottom of the second formwork 2. After the anchoring steel bar passes through the anchoring connection hole 9, epoxy resin anchoring glue or concrete structural glue is injected into the anchoring connection hole 9 to fix the anchoring steel bar to the second formwork 2. Specifically, the anchoring connection hole 9 is a truncated cone shape with a wide top and a narrow bottom, which is convenient for injecting epoxy resin anchoring glue or concrete structural glue and enhancing the anchoring effect; the minimum aperture of the anchoring connection hole 9 is larger than the diameter of the anchoring steel bar, leaving space for the anchoring steel bar to move in the anchoring connection hole 9, so that the second formwork 2 can still move slightly after being connected to the anchoring steel bar, thereby fine-tuning the position of the second formwork 2; another stud of the two-way tensioning bolt 10 is screwed into the slide nut at the top of the second formwork 2; one end of the tensioning screw 11 is passed through the fourth bolt hole 6 passing through the bottom of the second formwork 2 and connected to the second bolt hole 4 of the first formwork 1;

[0100] S8. Use the lead screw 101 of the two-way tension bolt 10 to connect the studs 102 at the top of the first and second templates, and turn the lead screw 101 of the two-way tension bolt 10. The lead screw 101 pulls the two studs 102, so that the relative position of the first template 1 and the second template 2 can be adjusted; put a gasket on the end of the tension screw 11 extending out of the second template 2, and then thread the nut to tighten the tension screw 11 through the gasket and the nut;

[0101] A fixture is placed on the top of the first template 1 and the second template 2, and the distance between the first template 1 and the second template 2 is determined by the fixture; the lead screw 101 is screwed, and the lead screw 101 drives the two studs 102 to move, thereby tightening or loosening the first template 1 and the second template 2;

[0102] S9, apply epoxy resin anchoring glue on the outer side and end UHPC liner of the first template 1 and the second template 2, then install the next first template 1 and the next second template 2 according to step S7, use a longitudinal bolt to pass through the second longitudinal connection hole 8 on the two second templates 2 to connect the two adjacent second templates 2; then use another longitudinal bolt to pass through the first longitudinal connection hole 7 on the two first templates 1 to connect the two adjacent first templates 1, finally connect the newly installed first template 1 and the second template 2 according to step S8, and temporarily anchor the newly installed first template 1 and the second template 2 according to step S81;

[0103] S10, connecting the remaining first formwork 1 and the second formwork 2 in sequence according to step S9, and pouring concrete between the first formwork 1 and the second formwork 2. Before pouring concrete, fill the fourth bolt hole 6 with foam glue to avoid leakage during concrete pouring.

[0104] The method for hoisting the first template 1 and the second template 2 in this embodiment is consistent with the hoisting method described in Example 1.

[0105] Specifically, the first bolt hole 3 and the second bolt hole 4 may be formed by pre-embedded bolt barrels, and the fourth bolt hole 6 is a through hole.

[0106] When the first template 1 and the second template 2 are placed at the installation position, if the bolt holes on the first template 1 and the second template 2 deviate in the length direction and cannot be aligned and connected due to reasons such as incorrect reserved positions of the bolt holes, the position of the third bolt hole 5 can be adjusted by sliding the slot nut. After the position of the slot nut is determined, the two-way tensioning bolt 10 is screwed in. The position of the slot nut can be fixed by tightening the two-way tensioning bolt 10 to a certain extent. The fourth bolt hole 6 is a long hole, and the tension screw 11 can move in the fourth bolt hole 6, thereby realizing the position adjustment of the tension screw 11 in the length direction, and preventing the second bolt hole 4 and the fourth bolt hole 6 from having positions that do not correspond in the length direction.

[0107] When the first template 1 and the second template 2 are placed at the installation position, if there is a deviation in the height direction of the bolt holes on the first template 1 and the second template 2 and they cannot be aligned for connection, they can be adjusted by setting a pad or a gasket at the bottom of the second template 2 or the bottom of the positioning protrusion 17 of the first template 1.

[0108] Specifically, the clamp is T-shaped, that is, the clamp includes a spacing block and a top plate, the top plate is fixed on the top of the spacing block, and the spacing blocks extend from both ends of the top plate respectively, and the length of the spacing block is set according to the required spacing between the first template 1 and the second template 2; during construction, the extended ends of the top plate are respectively placed on the top of the first template 1 and the second template 2, and the spacing block is located between the first template 1 and the second template 2. When the first template 1 and the second template 2 clamp the spacing block, the spacing adjustment between the first template 1 and the second template 2 is completed.

[0109] While embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A prefabricated UHPC bridge guardrail permanent formwork, characterized by: The invention comprises a first template (1), a second template (2), a bidirectional tension bolt (10) and a tension screw (11), wherein a bolt hole protrusion (16) is arranged on the inner side of the top of the first template (1) along the length direction, and a plurality of first bolt holes (3) are arranged on the bolt hole protrusion (16) along the length direction, a positioning protrusion (17) is arranged on the inner side of the bottom of the first template (1) along the length direction, and a plurality of second bolt holes (4) are arranged on the positioning protrusion (17) along the length direction, first longitudinal connecting holes (7) are arranged on the inner side of both ends of the first template (1), and a plurality of first longitudinal connecting holes (7) are arranged on the inner side of the top of the second template (2) along the length direction. a plurality of third bolt holes (5); a plurality of fourth bolt holes (6) are arranged at the bottom of the second template (2) along the length direction; second longitudinal connection holes (8) are arranged at the inner sides of both ends of the second template (2); anchor connection holes (9) are arranged at both ends and the middle position of the inner side of the bottom of the second template (2); the anchor connection holes (9) are located below the second longitudinal connection holes (8) and the fourth bolt holes (6); a plurality of supporting steel bars (12) are fixed at the inner positions of the middle parts of the first template (1) and the second template (2) along the length direction; and the first template (1) and the second template (2) are both formed of UHPC material; The plurality of support steel bars (12) on each template are spot welded to an internal steel bar (13), the internal steel bar (13) is buried in the middle of the template, the internal steel bars (13) are arranged along the length direction of the template, and the support steel bars (12) are also buried in a part of the template, with the buried depth being greater than or equal to 1 times the diameter of the support steel bars (12); The bidirectional tension bolt (10) comprises two studs (102) and a lead screw (101), wherein the lead screw (101) is provided with a threaded hole at each end, and a through hole is provided in the middle of the lead screw (101), the through hole being connected to the two threaded holes, and the through hole is used to provide a moving space for the studs (102), and the two studs (102) are respectively threadedly connected to the threaded holes at the two ends of the lead screw (101); The two studs (102) of the bidirectional tensioning bolt (10) are respectively connected to the first bolt hole (3) and the third bolt hole (5), and the two ends of the tensioning screw rod (11) are respectively connected to the second bolt hole (4) and the fourth bolt hole (6); A first UHPC liner (14) is provided on the inner side of one end of the first template (1), and one end of the first UHPC liner (14) extends outside the first template (1); a second UHPC liner (15) is provided on the inner side of one end of the second template (2), and one end of the second UHPC liner (15) extends outside the second template (2); the first UHPC liner (14) and the second UHPC liner (15) are located in corresponding positions; The third bolt hole (5) comprises a reserved groove, a nut track and a slide groove nut, the reserved groove is formed on the second template (2), the nut track is fixed in the reserved groove, the slide groove nut is slidably arranged on the nut track, and a screw rod of the bidirectional tension bolt (10) is threadedly connected to the slide groove nut; The fourth bolt hole (6) is a long through hole, one end of the tension screw rod (11) is threadedly connected to the second bolt hole (4), the other end of the tension screw rod (11) passes through the fourth bolt hole (6) and is located outside the second template (2), and one end of the tension screw rod (11) located outside the second template (2) is sleeved with a gasket and threadedly connected with a nut; The anchor connection hole (9) is in the shape of a truncated cone that is wide at the top and narrow at the bottom. The minimum hole diameter of the anchor connection hole (9) is larger than the diameter of the anchor steel bar. After the anchor steel bar passes through the anchor connection hole (9), epoxy resin anchor glue or concrete structural glue is injected into the anchor connection hole (9).

2. A prefabricated UHPC bridge guardrail permanent formwork according to claim 1, characterized in that: The UHPC components used to make the first template (1) and the second template (2) include 45% to 53% by weight of a cementitious system, 7.2% to 8.7% by weight of water, 43.75% to 48.4% by weight of fine aggregate, 1% to 1.62% by weight of organic fiber, and 0.82% to 1.2% by weight of an admixture; The water-cement ratio is 0.16~0.18, the sand-cement ratio is 0.82~1.02, the amount of admixture is 1.7%~2.3% of the cementitious material, and the fiber volume content is 1.8%~2.2%.

3. A prefabricated UHPC bridge guardrail permanent formwork according to claim 2, characterized in that: The cementitious system comprises 60% to 70% by weight of cement, 5% to 15% by weight of fly ash, 10% to 15% by weight of microsilica fume, and 15% to 25% by weight of slag.

4. A prefabricated UHPC bridge guardrail permanent formwork according to claim 3, characterized in that: The cement is slag cement or ordinary Portland cement with a grade greater than or equal to 42.5, the fly ash is ultrafine fly ash, the fine aggregate is river sand or quartz sand or recycled fine aggregate, the admixture is a polycarboxylic acid-based high-efficiency water reducer and a superdispersant, or a superplasticizer and a defoaming agent, and the organic fiber is an ultra-high molecular weight polyethylene fiber with a diameter of 20 μm and a length of 12 mm.

5. A construction method for prefabricated UHPC bridge guardrail permanent formwork according to claim 4, characterized in that: The following steps are involved: S1, prefabricating a first template (1) and a second template (2): when prefabricating the first template (1), a first bolt hole (3), a second bolt hole (4) and a first longitudinal connection hole (7) are preset, and supporting steel bars (12) are pre-embedded; when prefabricating the second template (2), a third bolt hole (5), a fourth bolt hole (6), a second longitudinal connection hole (8) and an anchor connection hole (9) are preset, and supporting steel bars (12) are pre-embedded; the inner sides of the first template (1) and the second template (2) are respectively roughened, and the roughening treatment is completed before the templates begin to set; S2, transporting the prefabricated first template (1) and second template (2) to the construction site; S3. Position and lay out the anti-collision guardrail and determine the installation position of the guardrail; S4. Roughen the base surface of the guardrail installation location; S5, tying guardrail steel bars, wherein the guardrail steel bars are located between the installation positions of the first template (1) and the second template (2); S6. Pre-plant anchoring steel bars and adjust the anchoring steel bars; S7. Lift the first template (1) to the installation position, screw a stud of the bidirectional tensioning bolt (10) into the first bolt hole (3) at the top of the first template (1), and apply epoxy resin anchoring glue or concrete structural glue to the bottom of the positioning protrusion (17); The second template (2) is hoisted to the installation position, and the anchoring steel bar is passed through the anchoring connection hole (9) at the bottom of the second template (2), wherein the anchoring connection hole (9) is in the shape of a truncated cone with a width at the top and a narrowness at the bottom. After the anchoring steel bar passes through the anchoring connection hole (9), epoxy resin anchoring glue or concrete structural glue is injected into the anchoring connection hole (9) to fix the anchoring steel bar to the second template (2); another stud of the bidirectional tensioning bolt (10) is screwed into the slot nut at the top of the second template (2); one end of the tensioning screw (11) is passed through the fourth bolt hole (6) at the bottom of the second template (2) and connected to the second bolt hole (4) of the first template (1); S8. Use the lead screw (101) of the bidirectional tension bolt (10) to connect the studs (102) at the top of the first and second templates; put a gasket on the end of the tension screw (11) extending out of the second template (2), and then thread the nut to tighten the tension screw (11) through the gasket and the nut; place a fixture on the top of the first template (1) and the second template (2), and use the fixture to determine the distance between the first template (1) and the second template (2); turn the lead screw (101), the lead screw (101) drives the two studs (102) to move, thereby tightening or loosening the first template (1) and the second template (2); turn the nut, and loosen or tighten the first template (1) and the second template (2) by changing the position of the nut on the tension screw (11); S9, applying epoxy resin anchoring glue on the outer side surfaces and end UHPC linings of the first template (1) and the second template (2), and then installing the next first template (1) and the next second template (2) according to step S7, using a longitudinal bolt to pass through the second longitudinal connection holes (8) on the two second templates (2) to connect the two adjacent second templates (2); then using another longitudinal bolt to pass through the first longitudinal connection holes (7) on the two first templates (1) to connect the two adjacent first templates (1), and finally connecting the newly installed first template (1) and the second template (2) according to step S8; S10, according to step S9, sequentially connect the remaining first templates (1) and second templates (2), and pour concrete between the first template (1) and the second template (2), and fill the fourth bolt hole (6) with foam glue before pouring concrete.

6. A construction method for prefabricated UHPC bridge guardrail permanent formwork according to claim 5, characterized in that: The step S6 specifically includes: pre-planting anchor steel bars and adjusting the anchor steel bars; and setting temporary anchor points on the bridge deck; Step S81: After completing step S8, use steel wires in conjunction with bidirectional tension bolts (10) to temporarily support the first and second templates, one end of the steel wire is temporarily connected to the bidirectional tension bolts (10) on the top of the template, and the other end of the steel wire is connected to the temporary anchor point of the bridge surface; The step S9 specifically comprises: after connecting the newly installed first template (1) and the second template (2) according to step S8, temporarily supporting the newly installed first template (1) and the second template (2) according to step S81.

7. A construction method for prefabricated UHPC bridge guardrail permanent formwork according to claim 5, characterized in that: Step S7 is specifically as follows: hoisting the first template (1) to the installation position, adjusting the position of the first template (1), spot welding the support steel bar (12) to the guardrail steel bar, screwing a stud of the bidirectional tension bolt (10) into the first bolt hole (3) at the top of the first template (1), and applying epoxy resin anchor glue or concrete structural glue to the bottom of the positioning protrusion (17); hoisting the second template (2) to the installation position, allowing the anchor steel bar to pass through the anchor connection hole (9) at the bottom of the second template (2), wherein the anchor connection hole (9) is wide at the top and narrow at the bottom. The anchor connection hole (9) is of truncated cone type, and the minimum hole diameter of the anchor connection hole (9) is larger than the diameter of the anchor steel bar. After the anchor steel bar passes through the anchor connection hole (9), epoxy resin anchor glue or concrete structure glue is injected into the anchor connection hole (9) to fix the anchor steel bar to the second template (2); another stud of the two-way tension bolt (10) is screwed into the slide nut at the top of the second template (2); one end of the tension screw (11) is passed through the fourth bolt hole (6) at the bottom of the second template (2) and connected to the second bolt hole (4) of the first template (1).

8. The construction method of a prefabricated UHPC bridge guardrail permanent formwork according to claim 5, characterized in that: The method for hoisting the first template (1) and the second template (2) is: Lifting the first template (1): installing a lifting ring in the first bolt hole (3), passing a lifting belt through the lifting ring, and connecting the first template (1) and the lifting equipment via the lifting belt, with no less than two lifting points and symmetrically arranged; Lifting the second template (2): passing the lifting belt through the fourth bolt hole (6), connecting the second template (2) and the lifting equipment through the lifting belt, with no less than two lifting points and symmetrically arranged; After the first template (1) and the second template (2) are connected, the lifting ring is removed.

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