CN105386441A - PVC pipe wrapped inner supporting cross prestress recycled concrete tubular pile - Google Patents

Abstract

The invention discloses a cross-shaped prestressed recycled concrete pipe pile supported by an outsourcing PVC pipe, which is mainly made of a PVC pipe, a circular steel cage frame, a cross-shaped steel frame and recycled concrete, and the circular steel cage frame and the cross-shaped steel frame Placed in the PVC pipe, the recycled concrete forms a circular inner cavity in the PVC pipe; the circular steel cage skeleton is welded by longitudinal prestressed tendons and spiral stirrups. Among them, the corrosion-resistant, lightweight and high-strength PVC pipe outsourcing the pile body can effectively prevent the pile body from being corroded, solve the corrosion problem of the pipe pile, and improve the durability of the pile foundation; , the respective advantages of prestressed steel bars and concrete, improve the mechanical properties of recycled concrete, improve the bearing capacity and stability of single piles, increase the lateral stiffness of piles, and reduce lateral deformation; making full use of waste concrete as recycled aggregates is beneficial Recycled concrete is popularized and applied in building foundation engineering.

Description

Cross-shaped prestressed recycled concrete pipe piles supported by outsourcing PVC pipes

technical field

The invention belongs to the field of pile foundation engineering in building foundation engineering, and in particular relates to a cross-shaped prestressed recycled concrete pipe pile supported inside an outsourcing PVC pipe.

Background technique

With the rapid development of the world economy, reinforced concrete structures have entered a period of rapid development, and the construction of new buildings and the demolition of old buildings will produce a large amount of waste concrete. Making full use of these waste concrete can not only effectively reduce the amount of construction waste, reduce the pollution of construction waste to the natural environment, and play a role in protecting the environment. The mining of natural aggregates achieves the purpose of saving natural sand resources and protecting the environment. However, due to the existence of old mortar, the performance of recycled coarse aggregate is quite different from that of natural coarse aggregate, such as low apparent density, high crushing index, high porosity, and high water absorption. Compared with ordinary concrete, recycled concrete has differences in physical, mechanical and durable properties. To apply recycled aggregates to pile foundations, new construction techniques must be adopted to improve the bearing capacity and durability of piles.

Prestressed concrete pipe piles can be widely used in housing construction projects, roads and bridges, seaports and wharves, and ocean engineering due to their reliable pile quality, high bearing capacity, and strong adaptability. For reinforced concrete piles serving in oceans, ports, saline-alkali areas, groundwater or inland areas with high concentrations of corrosive media in the soil, if no protective measures are taken, the pile body will be corroded by corrosive substances for a long time, such as chlorine Ion penetration, sulfate corrosion, freeze-thaw cycles, etc., will lead to severe deterioration of the pile body, shortened service life, and the durability of the pile foundation is very prominent.

Steel concrete structure can give full play to the respective advantages of steel and concrete. It is a structure with high bearing capacity, good ductility and good seismic performance. It has been widely used in building structures at home and abroad, but it is less used in pile foundations, especially Prestressed piles.

At present, the state advocates the policy of "replacing steel with plastic", encourages the use and actively promotes new chemical building materials such as plastic products. Polyvinyl chloride (PVC) material is widely used in construction, industry, agriculture, electronic , medical, automotive and other fields. However, according to the current traditional construction technology, the production of prefabricated piles requires multiple processes such as formwork support and formwork removal, which consumes a lot of steel forms and increases the workload and construction costs.

Contents of the invention

The technical problem to be solved by the present invention is to provide a cross-shaped prestressed recycled concrete pipe pile supported by an outsourcing PVC pipe with good pile foundation durability, strong single pile bearing capacity and deformation resistance.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

The cross-shaped prestressed recycled concrete pipe pile supported by the outsourcing PVC pipe is mainly made of PVC pipe, circular steel cage skeleton, cross-shaped steel frame and recycled concrete. The circular steel cage skeleton and cross-shaped steel frame are placed in the PVC pipe (ie : The PVC pipe is outsourced with longitudinal prestressed tendons, spiral stirrups, and cross-shaped steel frames), pouring recycled concrete in the pipe, tensioning the prestressed tendons, and adopting a centrifugal process to make the recycled concrete evenly dense along the periphery of the PVC pipe, and the recycled concrete is formed in the PVC pipe Circular inner cavity; the circular steel cage skeleton is welded by longitudinal prestressed tendons and spiral stirrups.

The PVC pipe is spliced by two upper and lower semicircular PVC pipes, and the interface is sealed and glued with PVC adhesive.

The longitudinal prestressed tendons are made of steel rods for prestressed concrete, and the longitudinal prestressed tendons are evenly arranged along the circumference, and the distance between the longitudinal prestressed tendons is not less than 6cm; the spiral stirrups are made of low carbon steel hot-rolled round wire rods or cold drawn low carbon Steel wire with a diameter of 4mm to 8mm.

The cross-shaped steel frame is made of two strip-shaped steel plates connected by mortise and tenon to form a cross shape and welded with spiral stirrups. The steel used for the strip-shaped steel plates is Q215B or Q235B. The width of each inner support steel plate is 40mm-80mm, and the thickness is 10mm-20mm. , the distance between each inner support is 1m; or the cross-shaped steel frame is welded by cross-crossing two steel bars with a diameter of more than 25mm.

Recycled concrete is composed of new mortar and recycled coarse aggregate. The particle size range of recycled coarse aggregate is 5mm-25mm, and the strength grade is C50-C60.

The cross-shaped prestressed recycled concrete pipe pile supported by the outsourcing PVC pipe also includes an end plate and a pile collar, and the cross-shaped steel frame is welded with the spiral stirrup and the end plate, and the three are concentrically arranged.

Aiming at the existing problems of concrete pipe piles at present, the inventor gave full play to the advantages of PVC pipes, combined PVC pipes and recycled concrete, and designed and produced a brand-new composite member—a cross-shaped prestressed recycled concrete pipe pile supported by outsourcing PVC pipes , mainly made of PVC pipe, circular steel cage skeleton, cross-shaped steel skeleton and recycled concrete, the circular steel cage skeleton and cross-shaped steel skeleton are placed in the PVC pipe, and the recycled concrete forms a circular cavity in the PVC pipe; the circular The steel cage skeleton is welded by longitudinal prestressed tendons and spiral stirrups. Among them, the corrosion-resistant, lightweight and high-strength PVC pipe outsourcing the pile body can effectively prevent the pile body from being corroded, solve the corrosion problem of the pipe pile, and improve the durability of the pile foundation; , the respective advantages of prestressed steel bars and concrete, improve the mechanical properties of recycled concrete, improve the bearing capacity and stability of single piles, increase the lateral stiffness of piles, and reduce lateral deformation; making full use of waste concrete as recycled aggregates is beneficial Recycled concrete is popularized and applied in building foundation engineering.

Compared with traditional concrete pipe piles, the present invention has the following outstanding advantages:

1. The pile body is covered with a corrosion-resistant, lightweight and high-strength PVC pipe, which can effectively block the erosion of the corrosive medium on the prestressed pile, prevent the deterioration of the pile body, and solve the durability problem of the pile foundation in a corrosive environment;

2. The inner support cross-shaped steel frame can give full play to the respective advantages of steel, prestressed steel bars and concrete, improve the mechanical performance of recycled concrete, improve the bearing capacity and stability of single piles, increase the lateral stiffness of the pile body, and reduce the lateral Deformation, reducing section size.

3. The PVC pipe can be used as a construction formwork for pouring concrete, which saves the steel formwork used in the traditional construction process, and eliminates the formwork removal process, speeds up the construction speed, and improves economic benefits;

4. The outsourcing PVC pipe effectively protects the inner concrete, which can reduce the thickness of the protective layer. Under the premise of meeting the bearing capacity requirements, it can reduce the size of the pipe pile, save materials and reduce the cost;

5. Making full use of construction waste as recycled aggregate is conducive to the popularization and application of recycled concrete in construction foundation projects and the recycling of construction waste, which plays a role in protecting the environment.

Description of drawings

Fig. 1 is a schematic structural view of a cross-shaped prestressed recycled concrete pipe pile supported in an outsourcing PVC pipe of the present invention.

Fig. 2 is a cross-sectional view of the pile body of the recycled concrete pipe pile in Fig. 1 along the cutting line A-A.

Fig. 3 is a cross-sectional view of the pile body of the recycled concrete pipe pile in Fig. 1 along the cutting line B-B.

Fig. 4 is a cross-sectional view of the pile body of the recycled concrete pipe pile in Fig. 1 along the cutting line C-C.

Fig. 5 is a schematic diagram of recycled concrete in the recycled concrete pipe pile of Fig. 1 .

In the figure: 1 PVC pipe; 2 Spiral stirrups in the densified area; 3 Recycled concrete; 4 Longitudinal prestressed tendons; 5 Spiral stirrups in the non-densified area; ; 10 to attach old mortar; 11 to new mortar.

detailed description

As shown in Figures 1 to 5, the cross-shaped prestressed recycled concrete pipe pile (400mm in outer diameter, 95mm in wall thickness, and 9m in length) supported in the outsourcing PVC pipe of the present invention mainly consists of PVC pipe 1, a circular steel cage skeleton, ten The glyph steel frame 6 is made of recycled concrete, the circular steel cage skeleton and the cross-shaped steel frame are placed in the PVC pipe (that is, the PVC pipe is covered with longitudinal prestressed tendons, spiral stirrups, and cross-shaped steel frame), and the recycled concrete is poured in the pipe 3. Stretch the prestressed tendons, adopt the centrifugal process to make the recycled concrete evenly dense around the PVC pipe, and the recycled concrete forms a circular cavity in the PVC pipe; the circular steel cage skeleton is welded by longitudinal prestressed tendons and spiral stirrups. in,

The PVC pipe is spliced by two upper and lower semicircular PVC pipes, the outer diameter is 400mm, the pipe thickness is 5mm, and the joint is sealed and glued with PVC adhesive.

The longitudinal prestressing tendons 4 are made of 10A10.7 steel rods for prestressing concrete, and the longitudinal prestressing tendons are evenly arranged along the circumference, and the distance between the longitudinal prestressing tendons is not less than 6cm; , the pitch of the spiral stirrup 2 (L ₁ , within 2m at both ends of the pipe pile) in the dense area is 45mm, the pitch of the spiral stirrup 5 (L ₂ ) in the non-densified area is 80mm, and the thickness of the protective layer is 20mm.

The cross-shaped steel frame is composed of two strip steel plates connected by mortise and tenon to form a cross shape and welded with spiral stirrups. The steel material used for the strip steel plates is Q235B. The width of each inner support plate is 50mm and the thickness is 20mm. The distance between each inner support 1m.

Recycled concrete is composed of new mortar and recycled coarse aggregate. The particle size range of recycled coarse aggregate is 5mm-25mm, and the strength grade is C60.

The recycled concrete pipe pile also includes an end plate 8 and a pile hoop 7, the cross-shaped steel frame is welded with the spiral stirrup and the end plate, and the three are concentrically arranged. The end plate is produced by a certain manufacturer, and the steel used is Q235B; the pile hoop is made of Q235B steel, which is rolled and pressed into a cylindrical shape by steel plate, and the joints are welded and rounded.

Production Method

1. According to the size of the round pile, make the cross-shaped steel frame, end plate and pile hoop.

2. Welded circular steel cage skeleton. According to the size of the round pile and the thickness of the protective layer, the stirrup is welded to the prestressed steel bar in a spiral form by a sliding welding machine, and the prestressed steel bar should be evenly arranged along the circumference.

3. Install the circular steel cage skeleton. Put the welded steel cage frame, cross-shaped steel frame, end plate and pile hoop into the lower half of the PVC pipe. The pile end plate and pile hoop should be welded evenly and continuously, and the steel cage skeleton, cross-shaped steel frame and PVC pipe are concentric place.

4. Concrete pouring. Use the feeder to pour concrete into the lower half of the PVC pipe. According to the feeding method of first the middle, then both ends, and then the middle, distribute the material evenly along the length of the PVC pipe to evenly fill the lower half of the PVC pipe with recycled concrete.

5. Mold closing. Put the upper half of the PVC pipe above the lower half of the PVC pipe, and fix the upper and lower PVC pipes tightly with a hoop to prevent the PVC pipe from loosening and slurry leakage during centrifugation.

6. Prestressed tension. A jack-type tensioning machine is used to perform overall tensioning of the prestressed tendons after mold closing.

7. Centrifugal molding process. Hang the above-mentioned pipe piles after clamping the mold to the centrifuge, accelerate step by step according to the centrifugal speed of low speed, low medium speed, medium speed and high speed, and centrifuge for 15 to 20 minutes, so that the recycled concrete is evenly dense along the periphery of the PVC pipe, and a circle is formed inside the pipe. shaped cavity.

8. Primary steam curing. Lift the centrifugally formed pipe piles to the atmospheric pressure steam curing pool for primary steam curing, stand at room temperature for 1h-2h, slowly raise the temperature to 90°C-100°C, and maintain at constant temperature for 4h-8h, so that the concrete test piles cured under the same conditions The compressive strength of the parts is up to 45Mpa.

9. Prestress the centrifugal pile after primary steam curing, and apply prestress to the pile body. Use PVC adhesive to seal the PVC interface, and leave the factory after natural curing reaches the factory strength.

Claims (6)

1. A cross-shaped prestressed recycled concrete pipe pile supported in an outsourcing PVC pipe is characterized in that it is mainly made of PVC pipe, circular steel cage skeleton, cross-shaped steel frame and recycled concrete, and the circular steel cage skeleton and cross-shaped steel The bone is placed in the PVC pipe, and the recycled concrete forms a circular cavity in the PVC pipe; the circular steel cage skeleton is welded by longitudinal prestressed tendons and spiral stirrups. 2. The cross-shaped prestressed recycled concrete pipe pile supported by an outsourcing PVC pipe according to claim 1, wherein the PVC pipe is formed by splicing two upper and lower semicircular PVC pipes. 3. The cross-shaped prestressed recycled concrete pipe pile supported in the outsourcing PVC pipe according to claim 1, characterized in that: the longitudinal prestressed tendons adopt steel rods for prestressed concrete, the longitudinal prestressed tendons are evenly arranged along the circumference, and the longitudinal prestressed tendons are uniformly arranged along the circumference. The distance between the prestressed tendons is not less than 6cm; the spiral stirrup is made of low-carbon steel hot-rolled round wire rod or cold-drawn low-carbon steel wire for concrete products, with a diameter of 4mm-8mm. 4. The cross-shaped prestressed recycled concrete pipe pile supported by an outsourcing PVC pipe according to claim 1, characterized in that: the cross-shaped steel frame is formed by two strip-shaped steel plates connected by mortise and tenon joints into a cross shape and connected with spiral stirrups Welding, the steel used for the strip steel plate is Q215B or Q235B, the width of each inner support plate is 40mm-80mm, the thickness is 10mm-20mm, and the distance between each inner support is 1m; or the cross-shaped steel frame is composed of two pieces with a diameter of more than 25mm It is made of cross-welded steel bars. 5. The cross-shaped prestressed recycled concrete pipe pile supported by outsourcing PVC pipes according to claim 1, characterized in that: the recycled concrete is composed of new mortar and recycled coarse aggregate, and the particle size range of the recycled coarse aggregate is 5mm- 25mm, the strength grade is C50~C60. 6. The cross-shaped prestressed recycled concrete pipe pile supported in the outsourcing PVC pipe according to claim 1 is characterized in that it also includes an end plate and a pile hoop, and the cross-shaped steel frame is welded to the spiral stirrup and the end plate. Arranged concentrically.