CN104278622A - Recycled-concrete cross steel-pipe special-shaped column pier - Google Patents

Abstract

The invention discloses a regenerative concrete ten-shaped steel pipe pier with special-shaped columns, which is composed of circular steel pipes and four U-shaped steel grooves welded together. The four sides of the circular steel pipe are used as the limbs of the cross-section pier; the circular steel pipe is poured with recycled aggregate concrete, and the U-shaped steel channel is poured with ordinary aggregate concrete. The invention overcomes the defect of relatively poor durability of the recycled concrete, improves its mechanical performance, and reduces people's doubts about the performance of the recycled concrete. Moreover, the utilization of recycled concrete is also a process of recycling waste, and local materials are used to reduce the transportation cost of materials. At the same time, since the outsourcing steel plate and circular steel pipe can be used as formwork, it is not necessary to carry out formwork engineering during the construction process. The present invention has the above prominent advantages, and is suitable for areas with high seismic intensity and areas where building materials are difficult to transport, and is also suitable for urban bridge projects that require construction time, construction impact, and curved routes.

Description

Recycled concrete ten-type steel pipe special-shaped column pier

technical field

The invention belongs to the technical field of steel and concrete composite structures and hybrid structures, and relates to bridge pier columns, in particular to a regenerative concrete ten-type steel pipe special-shaped column pier.

Background technique

With the passage of time, the number of old bridges has gradually increased, and many of them need to be demolished and rebuilt on the spot due to reasons such as difficulty in repairing and difficulty in meeting traffic capacity requirements. The traditional construction method is to transport out the waste generated from the demolition of the old bridge, clear the site, and then transport the equipment and materials required for the construction of the new bridge to the site to start the construction of the new bridge. In this way, the transportation requirements for construction waste and new construction materials are extremely high, resulting in rising costs, prolonging the construction period, and increasing the impact on the surrounding environment. At the same time, the project also needs to face the problem of disposal of construction waste, and the mining of new materials will also cause damage to the environment. Therefore, if the construction waste can be effectively used as a building material for new construction, the above-mentioned adverse effects will be reduced to a large extent.

The aggregate formed after crushing, cleaning and grading waste concrete blocks is called recycled aggregate; the concrete prepared with recycled aggregate partially or completely replacing natural aggregates such as sand and stone is called recycled aggregate concrete, or recycled concrete for short. The promotion and application of recycled concrete is conducive to the recycling of construction waste and meets the requirements of environmental protection and sustainable development. An important feature of sustainable development is environmental protection and protection of natural resources. Making full use of recycled 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 recycled aggregate concrete made of raw materials can also reduce the mining of natural aggregates in bridge engineering, and achieve the purpose of saving natural sand and stone resources. However, due to the inherent damage of recycled aggregate and the adsorption of a layer of old mortar on its surface, resulting in high water absorption, the strength, shrinkage and durability of recycled concrete are inferior to those of ordinary concrete. greatly limited its scope of use.

Contents of the invention

The technical problem to be solved by the present invention is to provide a recycled concrete ten-shaped steel pipe special-shaped column bridge pier with high bearing capacity, good torsion resistance and seismic performance, and rapid construction.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions: the recycled concrete ten-shaped steel pipe special-shaped column pier includes a cross-section pier body, and the cross-section pier body is composed of a circular steel pipe welded with four U-shaped steel channels, and the circular The steel pipe is the center of the cross-section pier, and four U-shaped steel channels are symmetrically distributed around the circular steel pipe as the limbs of the cross-section pier; the circular steel pipe is poured with recycled aggregate concrete, and the U-shaped steel channel is poured with ordinary concrete. feed concrete.

The U-shaped steel channel is welded by the outsourcing steel plate, the end adopts a semicircular design, and the straight section is welded and connected with the circular steel pipe.

The ratio of the diameter D of the circular steel pipe to the radius d of the semicircle at the end of the U-shaped steel channel should be around 0.3.

The ratio of the length M of the straight section of the U-shaped steel channel in the longitudinal direction of the bridge to the length N of the straight section of the U-shaped steel channel in the transverse direction of the bridge should be between 0.72 and 1.35.

The strength grade of ordinary aggregate concrete is not lower than C50, the strength grade of recycled aggregate concrete is not lower than C35, and the strength grade of ordinary aggregate concrete is greater than that of recycled aggregate concrete.

Recycled aggregate concrete is composed of new mortar and recycled aggregate, and recycled aggregate is composed of original natural aggregate and attached old mortar; ordinary aggregate concrete is composed of new mortar and ordinary natural aggregate.

Aiming at the problems existing in the application of recycled aggregate concrete, the inventor designed a recycled concrete ten-shaped steel pipe pier with special-shaped columns, which is composed of circular steel pipes and four U-shaped steel channels welded together, and the circular steel pipes are used as the center of the cross-section pier body , four U-shaped steel channels are symmetrically distributed around the circular steel pipe as the limbs of the cross-section pier; the circular steel pipe is poured with recycled aggregate concrete, and the U-shaped steel channel is poured with ordinary aggregate concrete. Since the recycled concrete is restrained by a large-diameter circular steel pipe in the center of the cross-section pier body, the steel pipe has a wrapping and restraining effect on the recycled concrete, which isolates the recycled concrete from the atmospheric environment and is in a triaxial compression state, which overcomes the problem of recycled concrete. The defects of relatively poor durability improve its mechanical performance and reduce people's doubts about the performance of recycled concrete. Moreover, the utilization of recycled concrete is also a process of recycling waste, and local materials are used to reduce the transportation cost of materials. At the same time, since the outsourcing steel plate and circular steel pipe can be used as formwork, formwork engineering is not necessary during the construction process. The present invention has the above prominent advantages, and is suitable for areas with high seismic intensity and areas where building materials are difficult to transport, and is also suitable for urban bridge projects that require construction time, construction impact, and curved routes. In addition, the unique shape of the present invention can also provide one more option for improving the urban landscape level.

Description of drawings

Fig. 1 is the schematic structural view of the recycled concrete ten-shaped steel pipe special-shaped column pier of the present invention.

In the figure: 1 circular steel pipe, 2 recycled aggregate concrete, 3 U-shaped steel channel, 4 ordinary aggregate concrete.

Detailed ways

As shown in Figure 1, the recycled concrete ten-shaped steel pipe special-shaped column bridge pier of the present invention includes a cross-section pier body, and the cross-section pier body is composed of a circular steel pipe 1 and four U-shaped steel channels 3 welded, and the circular steel pipe is used as a cross In the center of the cross-section pier body, four U-shaped steel channels are symmetrically distributed around the circular steel pipe as the limbs of the cross-section pier body; recycled aggregate concrete 2 is poured in the circular steel pipe, and ordinary aggregate concrete is poured in the U-shaped steel channel 4.

Production process

The U-shaped steel channel is welded by outsourcing steel plates, including two straight steel plates (straight part) and one semi-circular arc-shaped steel plate (semi-circular end); four U-shaped steel channels are welded with circular steel pipes to form a cross shape. Pouring recycled aggregate concrete inside the circular steel pipe, the recycled aggregate concrete is composed of new mortar and recycled aggregate, and the recycled aggregate is composed of original natural aggregate and attached old mortar; pouring ordinary aggregate concrete inside the U-shaped steel channel, Ordinary aggregate concrete consists of new mortar and ordinary natural aggregate. Among them, the strength grade of ordinary aggregate concrete is not lower than C50, the strength grade of recycled aggregate concrete is not lower than C35, and the strength grade of ordinary aggregate concrete is higher than that of recycled aggregate concrete.

Among them, the design dimensions of the circular steel pipe and recycled concrete are controlled by the axial compression and torsion state; the design dimensions of the U-shaped steel channel are mainly controlled by the bending moment caused by eccentric compression, and the design requirements of this part have been determined by The central CFST portion determined by the axial design is taken into account. The ratio of the diameter D of the circular steel pipe to the radius d of the semicircle at the end of the U-shaped steel channel should be around 0.3. The ratio of the length M of the straight section of the U-shaped steel channel in the longitudinal direction of the bridge to the length N of the straight section of the U-shaped steel channel in the transverse direction of the bridge should be between 0.72 and 1.35, which should be determined according to the specific design of the force transmitted by the superstructure , flexibly adjusted according to the difference in eccentric direction and size.

design principle

The recycled concrete ten-shaped steel pipe special-shaped column bridge pier of the present invention can not only meet the requirements of bearing capacity, but also has good seismic performance, can significantly improve the durability of recycled concrete, and realize waste recycling. In addition, the bridge pier is convenient for construction and low in cost.

The increase in bearing capacity is because the concrete inside the steel pipe is in a state of triaxial compression. When the axial force in the vertical direction increases, the concrete will deform laterally and expand outward, while the steel pipe has good tensile properties and is well organized. The lateral deformation and expansion of the concrete make the concrete under compression in all directions, and the development of micro-cracks will be restricted. This restriction is also effective under the action of earthquakes, thereby improving the seismic performance. Under triaxial compression, the mechanical properties of recycled concrete can also reach the level of ordinary concrete.

The construction is convenient and the cost is low because the outsourced steel pipes and U-shaped steel channels can be directly used as formwork during the construction process, saving the time and cost of special formwork engineering. At the same time, the waste resource utilization of construction waste greatly reduces the investment in purchasing and transporting materials, and realizes the real local and nearby materials.

Claims (6)

1. A recycled concrete ten-shaped steel pipe special-shaped column bridge pier, including a cross-section pier body, is characterized in that: the cross-section pier body is composed of circular steel pipes and four U-shaped steel grooves welded, and the circular steel pipes are used as cross-section piers. In the center of the cross-section pier body, four U-shaped steel channels are symmetrically distributed around the circular steel pipe as the limbs of the cross-section pier body; the circular steel pipe is poured with recycled aggregate concrete, and the U-shaped steel channel is poured with ordinary aggregate concrete. 2. The recycled concrete ten-shaped steel pipe special-shaped column pier according to claim 1, characterized in that: the U-shaped steel channel is welded by outsourcing steel plates, the end is designed with a semicircle, and the straight section is connected to the circular steel pipe by welding . 3. The recycled concrete ten-shaped steel pipe special-shaped column bridge pier according to claim 2, characterized in that: the ratio of the diameter D of the circular steel pipe to the radius d of the semicircle at the end of the U-shaped steel channel is 0.3. 4. The recycled concrete ten-shaped steel pipe special-shaped column bridge pier according to claim 3 is characterized in that: the length M of the straight section of the U-shaped steel channel in the longitudinal direction of the bridge and the partial length N of the straight section of the U-shaped steel channel in the transverse direction of the bridge The ratio is between 0.72 and 1.35. 5. The recycled concrete ten-shaped steel pipe special-shaped column pier according to claim 4, characterized in that: the strength grade of the ordinary aggregate concrete is not lower than C50, the strength grade of the recycled aggregate concrete is not lower than C35, and the ordinary aggregate concrete The strength level of concrete is greater than that of recycled aggregate concrete. 6. The recycled concrete ten-shaped steel pipe special-shaped column pier according to claim 5, characterized in that: the recycled aggregate concrete is composed of new mortar and recycled aggregate, and the recycled aggregate is composed of original natural aggregate and attached old mortar ; The ordinary aggregate concrete is composed of new mortar and ordinary natural aggregate.