CN108560423B

CN108560423B - Construction method of common steel bar and finish-rolled twisted steel bar mixed reinforcement assembly pier

Info

Publication number: CN108560423B
Application number: CN201810110414.8A
Authority: CN
Inventors: 王震宇; 蔡忠奎
Original assignee: Hengqin Gong'e Technology Co ltd
Current assignee: Hengqin Conjugate Technology Co., Ltd.
Priority date: 2018-02-05
Filing date: 2018-02-05
Publication date: 2020-06-30
Anticipated expiration: 2038-02-05
Also published as: CN108560423A

Abstract

The invention discloses a construction method of a section assembled pier of a mixed reinforcement of common steel bars and finish rolled twisted steel bars. Arranging metal corrugated pipes in the bearing platform and the prefabricated segment pier bodies to reserve a hole channel, vertically stacking the prefabricated segment pier bodies during construction, enabling unbonded prestressed tendons to penetrate the reserved hole channel on the cross section, tensioning, connecting the segment pier bodies into a whole, and avoiding grouting and sealing in the hole channel; and then according to a certain configuration proportion, vertically penetrating the common steel bars and the finish-rolled threaded steel bars into the pore channels and performing pressure grouting to finally form the segment assembling piers of the mixed reinforcement.

Description

Construction method of common steel bar and finish-rolled twisted steel bar mixed reinforcement assembly pier

Technical Field

The invention relates to a construction method of a prefabricated segment assembled concrete pier, in particular to a construction method of a common steel bar and finish-rolled twisted steel bar mixed reinforcement assembled pier.

Background

The bridge collapse caused by natural disasters such as earthquake and wars also needs to be urgently rebuilt by adopting a bridge rapid construction technology. The prefabricated segment assembled bridge system becomes one of effective schemes for meeting the requirements, and the good application prospect of the prefabricated segment assembled bridge system benefits from the following main advantages: (1) most of the components are manufactured industrially and assembled mechanically, so that the construction efficiency is outstanding; (2) the field construction period is short and is less influenced by seasons and weather; (3) the durability is high and the maintenance cost of the whole life cycle is reduced because the manufacturing and maintenance conditions of the components are good; (4) the interference to the ecological environment, the living environment and the existing traffic around the bridge site is small.

At present, the technology of adopting prefabricated sections to assemble and realize the rapid construction of the upper structure of the bridge is mature, compared with the prior art, the actual engineering application of the prefabricated assembled pier is rare, and the main reason is that the research and development and the application of the seismic performance of the novel pier are still lack. China is at the junction of the Pacific ocean seismic zone and the Mediterranean-Himalayan seismic zone, and is one of the most serious countries in the world. However, most of the research and invention of the existing assembled piers mainly aim at improving the construction convenience of the piers or reducing the damage degree of the piers after self-earthquake, and the maximum displacement response of the piers under earthquake excitation and the residual displacement after the earthquake are not effectively controlled at the same time.

The existing research shows that the maximum displacement response and the discreteness of the pier during earthquake can be effectively reduced by improving the post-yield rigidity of the pier, and meanwhile, the self-resetting capability of the pier is obviously improved, and the post-earthquake functionality of the bridge structure is ensured. The prefabricated segment splicing technology is utilized to realize the efficient and green construction of the reinforced concrete pier, and the post-yielding rigidity of the pier is obviously improved to improve the self anti-seismic performance and the self-resetting performance of the pier, so that the prefabricated segment splicing technology has outstanding practical significance for China entering the large-scale construction of traffic infrastructures. However, there is currently a lack of a mature solution to the problem of increasing post-yield stiffness of the sectional pier.

Disclosure of Invention

The invention solves the problem that the maximum displacement reaction when the pier is vibrated and the residual displacement after the pier is vibrated are difficult to simultaneously reduce in the existing pier assembling technology. The standard value of the yield strength of the common steel bar is 400-500 MPa, the standard value of the yield strength of the finish-rolled twisted steel bar is 785-1200 MPa, and the common steel bar and the finish-rolled twisted steel bar have the same elastic modulus. Therefore, when the spliced pier with the mixed reinforcing bars provided by the invention is subjected to earthquake disasters, the common reinforcing bars arranged in the pier yield first and dissipate the energy input into the bridge structure by the ground motion through elastic-plastic deformation, so that the dynamic reactions such as bridge displacement, acceleration and the like are favorably reduced; after the common steel bars are buckled, the finish-rolled twisted steel bars can still keep an elastic state, when the seismic strength is continuously increased, the pier position moving force reaction is increased, at the moment, the tensile stress level of the finish-rolled twisted steel bars is continuously increased, and the pier horizontal bearing capacity is increased along with the increase of the tensile stress level, so that the pier buckled rigidity is favorably improved. According to the invention, by adopting the scheme of mixing common steel bars and finish-rolled twisted steel bars for reinforcement, the rigidity of the pier after yielding is improved, the discreteness of the elastic-plastic maximum dynamic response of the pier under strong earthquake is reduced, and the performance-based anti-seismic design of the spliced pier is facilitated; the improvement of the rigidity of the pier after yielding can also effectively improve the self-recovery capability of the pier body, obviously reduce the residual deformation of the pier after the earthquake and improve the functionality and the repairability of the bridge structure after the earthquake; in addition, the construction method of the assembled pier is simple, convenient and feasible, has small construction difficulty and high efficiency, and ensures high efficiency and green construction of the pier.

The invention provides a construction method of a common steel bar and finish rolled twisted steel bar mixed reinforcement assembly pier, which comprises the following steps:

placing the metal corrugated pipe and the anchorage device at the lower end of the unbonded prestressed tendon 7 at a specified position in the concrete bearing platform 1, and pouring concrete of the bearing platform;

step two, manufacturing prefabricated sections 4 of the assembled pier body 2, and respectively manufacturing the reserved corrugated pore 5 and the prestressed tendon pore 8 through pre-buried metal corrugated pipes and PVC pipes;

thirdly, sequentially stacking each prefabricated segment 4, and enabling the prestressed tendons to penetrate through the prestressed tendon pore canals 8 in the center of each segment; in the assembling process, epoxy resin is uniformly brushed on the joint surfaces between the bottommost section and the bearing platform and between two adjacent sections;

tensioning the unbonded prestressed tendons 7, and sealing the anchor grooves 3 in the upper parts of the prestressed tendons;

putting the through longitudinal bars 6 into a corrugated duct 5 of the pier, and enabling each through longitudinal bar to be located at the center of the duct, wherein the through longitudinal bars comprise common steel bars and finish-rolled twisted steel bars; for the high pier, a welding joint or a steel bar mechanical connecting joint is adopted to lengthen a common steel bar, and a spiral connector is adopted to lengthen a finish-rolled twisted steel bar;

step six, using cement-based grouting material to perform grouting on the corrugated pore channel 5; a plurality of grouting holes are uniformly arranged along the vertical direction of the pier body, and grouting operation is carried out by adopting a segmented grouting mode and/or a pressure grouting method.

The invention provides an assembly pier for a common steel bar and finish rolled twisted steel bar mixed reinforcement, which comprises a concrete bearing platform 1, an assembly pier body 2, a through longitudinal bar 6 and an unbonded prestressed bar 7; the assembled pier bodies 2 are composed of one or more prefabricated sections 4, the through longitudinal bars 6 are formed by mixing two types of steel bars, namely common steel bars and finish-rolled threaded steel bars, and the through longitudinal bars and the unbonded prestressed bars 7 are used together for connecting the concrete bearing platform 1 and the assembled pier bodies 2 into a complete pier system.

The geometric dimension, the reinforcing bar structure and the used materials of each prefabricated segment 4 can be the same, so that the assembling difficulty is reduced, and the construction efficiency is improved; or may be different to reduce pier prefabrication costs. The upper end surface and the lower end surface of each prefabricated segment 4 can be planes, and the shearing force generated under the action of an earthquake can be effectively transmitted between the upper segment and the lower segment through a friction shearing mechanism; in addition, according to the requirement of anti-seismic design, the upper end surface and the lower end surface of the prefabricated segment 4 can be provided with a single shear key or a plurality of shear keys, so that the upper segment and the lower segment which are adjacent after being assembled are mutually occluded, and the shear-resistant bearing capacity at the splicing seam can be effectively improved.

The types of the common steel bars used for penetrating the longitudinal bars 6 are HRB400, HRB500, HRBF400, HRBF500, HRB400E, HRB500E, HRBF400E and HRBF 500E. The types of finish-rolled threaded steel bars used for the through longitudinal bars 6 are PSB785, PSB830, PSB930, PSB1080, and PSB 1200.

Corrugated pore channels 5 are reserved in the concrete bearing platform 1 and each prefabricated segment 4. The reserved corrugated hole 5 is realized by embedding a circular metal corrugated pipe, and the diameter of the corrugated pipe is (2 to 3)dWhereindIn order to communicate the diameter of the longitudinal bar, the larger of the common steel bar and the finish-rolled twisted steel bar is taken. The metal corrugated pipe should meet the requirements of specification' Metal corrugated pipe for prestressed concrete (JG 225-. The length of the corrugated pipe embedded in the bearing platform is not less than 36d，dIn order to communicate the diameter of the longitudinal bar, the larger of the common steel bar and the finish-rolled twisted steel bar is taken. In addition, the lower end of the finish-rolled threaded steel bar is provided with a nut anchorage matched with the bar material so as to enhance the anchoring performance.

The lower end of the unbonded prestressed tendon 7 is poured in the concrete bearing platform 1, the tendon bundle sequentially passes through the prestressed tendon pore channel 8 with smooth inner wall reserved in each prefabricated segment 4 when the pier is assembled, the upper part of the tendon bundle is placed in the prestressed tendon anchorage device groove 3 of the topmost segment, and the anchorage is sealed after the prestressed tendon is tensioned. The type of the prestressed tendon used by the unbonded prestressed tendon 7 is a steel strand, a prestressed twisted steel bar or an FRP prestressed tendon.

Compared with the prior art, the invention has the following advantages:

the longitudinal steel bar is formed by mixing common steel bars with lower yield points and finish rolling twisted steel bars with high yield points, and can obviously improve the rigidity of the pier after yielding, thereby reducing the maximum displacement reaction and the discreteness of the pier under earthquake excitation, effectively improving the self-resetting capability of the pier, reducing the residual deformation after earthquake, and improving the functionality of the bridge structure after earthquake.

By adjusting the configuration proportion of the common steel bars and the finish rolled deformed steel bars, the yield bearing capacity, the post-yield rigidity, the peak bearing capacity and the ultimate displacement angle of the pier can be effectively controlled, and therefore the design of the pier under the multi-performance level is achieved.

The pier provided by the invention has outstanding hysteretic energy dissipation capability and can effectively absorb and dissipate the energy input to the bridge structure during earthquake, so that an energy dissipation damper or a shock insulation support does not need to be additionally arranged, and the bridge construction cost is reduced.

The pier longitudinal ribs are wrapped by the high-strength grouting material, and the outside of the grouting material is also restrained by the metal corrugated pipes and the stirrups, so that the longitudinal ribs cannot be subjected to compression buckling damage under the action of an earthquake; on the other hand, the high-strength grouting material constrained by the metal corrugated pipe can participate in compression together with the concrete, so that the compression stress level and the compression stress level of the concrete are low, and the damage degree is not large. Therefore, the pier provided by the invention is low in repair difficulty after earthquake, and is beneficial to realizing the rapid recovery of the bridge traffic network in the disaster area.

The pier provided by the invention is simple in assembly process, and has low requirement on operation precision during assembly; and large-scale equipment is not needed during transportation and hoisting, the construction is flexible, the efficiency is high, and the bridge rapid construction is facilitated.

Drawings

FIG. 1 is a cross-sectional view of a hybrid reinforcement assembled pier;

FIG. 2 is a perspective view of a single prefabricated segment;

FIG. 3 is a schematic cross-sectional view of a fabricated pier of the hybrid reinforcement bar;

FIG. 4 is a schematic view of the construction process of the assembled pier of the hybrid reinforcement of the present invention;

FIG. 5 is a cross-sectional view of a sectional pier of the hybrid reinforcement bar of example 2;

fig. 6 is a cross-sectional view of a sectional pier of the hybrid reinforcement bar of example 3.

The parts in the drawings are numbered as follows: 1. a bearing platform; 2. assembling the pier body; 3. a prestressed tendon anchorage groove; 4. prefabricating a segment; 5. reserving a corrugated hole channel; 6. penetrating the longitudinal ribs; 7. the prestressed tendons are not bonded; 8. a prestressed tendon duct; 9. a metal bellows; 10. ordinary steel bars; 11. finish rolling the twisted steel; 12. and (5) hooping.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and the present invention will be further described. Like reference symbols in the various drawings indicate like elements. The following examples are illustrative and are not to be construed as limiting the invention.

Example 1, a construction method of an assembly pier of a common steel bar and finish rolled twisted steel bar mixed reinforcement is shown in fig. 4: firstly, pouring a pier bearing platform foundation, and reserving a corrugated pore passage during pouring so as to insert a through longitudinal rib into the foundation for anchoring; then, assembling the pier bottom sections, and sequentially assembling the other sections to enable the prestressed tendons to pass through the prestressed tendon pore passages 8 of the sections; after the assembly is finished, tensioning the prestressed tendons; and finally, the through longitudinal ribs are placed into the reserved corrugated pore canal 5, and pressure grouting is carried out on the pore canal, so that the grouting is ensured to be full and compact. The through longitudinal bars are restrained by the surrounding grouting material, the metal corrugated pipe 9 and the stirrups 12, so that the through longitudinal bars are not easy to be subjected to compression buckling damage under the action of an earthquake. And because of the synergistic compression resistance of the grouting material, the concrete compression stress and plastic damage are not large during earthquake. Therefore, the pier has good post-earthquake functionality and is beneficial to realizing the post-earthquake smoothness of the important bridge structure.

Example 2, as shown in fig. 5, this example is different from the previous example 1 in that the pier body of the assembled pier of the conventional rebar and finish-rolled twisted rebar mixed reinforcement has only one prefabricated section 4. When the length-to-fineness ratio of the pier is not more than 6, the whole pier body can be prefabricated as a whole segment, so that the pier assembling efficiency can be improved. Moreover, because the length-to-slenderness ratio of the piers is not more than 6, the size and weight of the whole segment are not too large to be transported and assembled. When the same or similar design and construction scheme as in example 2 is adopted, it should be noted that the size and weight of the prefabricated pier shaft segment meet the relevant transportation regulations and do not exceed the tonnage limit of the hoisting equipment.

Embodiment 3, as shown in fig. 6, the present embodiment is different from the foregoing embodiment 1 in that the general reinforcing bars and the finish-rolled twisted reinforcing bars pass through only the lower segments of the erection body 2, and are not arranged along the entire erection body. For the cantilever pier, the bending moment of the pier bottom is the largest under the action of an earthquake, and the bending moment is gradually reduced from the pier bottom to the top. The longitudinal reinforcing steel bar reinforcement ratio can be gradually reduced according to pier bending moment distribution during earthquake-proof design, and finally the longitudinal reinforcing steel bar reinforcement ratio is cut at a certain reasonable height. The determination of the truncation position of the longitudinal rib is in accordance with the corresponding anti-seismic design specification. When the height of the assembling pier of the common steel bar and finish rolling twisted steel bar mixed reinforcement is larger, the steel consumption can be effectively reduced by adopting the scheme on the premise of ensuring the unchanged anti-seismic performance, the construction progress is accelerated, and the economic benefit is improved.

Embodiment 4, as shown in fig. 1, the present invention provides an assembled pier of a reinforcing bar mixed by a general reinforcing bar and a finish rolled twisted reinforcing bar, comprising a concrete cap 1, an assembled pier body 2, a through longitudinal bar 6, and an unbonded prestressed bar 7. The assembled pier body is formed by vertically stacking a certain number of single prefabricated sections 4 and is stretched into a whole pier through unbonded prestressed tendons 7. Each prefabricated segment 4 has a rectangular cross-section of the same size and the height of each segment is the same. The height of the segments is 1.5-4 times of the length of the long side of the section, so that the pier plastic hinges can be fully developed to ensure the anti-seismic energy dissipation capacity, and the volume and the weight of a single segment are small, so that the assembly is easy. As shown in fig. 2, each prefabricated segment 4 is provided with the same number of pre-corrugated tunnels 5 at the same cross-sectional position. Therefore, the reserved corrugated pore passage 5 and the prestressed tendon pore passage 8 can be ensured to be communicated up and down after assembly. After the prefabricated sections 4 are assembled and the prestressed tendons 7 are tensioned, the through longitudinal tendons 6 are placed into the reserved corrugated hole channels. If the length of the single through longitudinal rib 6 is smaller than the height of the pier body, the through longitudinal rib 6 is lengthened through mechanical connection, welding or binding connection. The connection extension operation of the through longitudinal ribs should meet the corresponding specification. The through longitudinal bar 6 is formed by mixing common hot-rolled ribbed steel bars and finish-rolled twisted steel bars, and the ratio of the reinforcement ratio of the two is 0.5-2.0. The two kinds of steel bars are mixed and configured, so that the post-yield rigidity of the pier can be effectively improved, and the anti-seismic performance and the self-resetting capability of the pier are comprehensively improved. In cross section, as shown in fig. 3, two longitudinal ribs are arranged at intervals.

Finally, the above examples are only for illustrating the technical solutions of the present invention and are not limiting.

Claims

1. A construction method of a common steel bar and finish rolled twisted steel bar mixed reinforcement splicing pier comprises the following steps:

placing a metal corrugated pipe and an anchorage device at the lower end of an unbonded prestressed tendon (7) at a specified position in a concrete bearing platform (1), and pouring concrete of the bearing platform;

step two, manufacturing a prefabricated section (4) for assembling the pier body (2), and respectively manufacturing the reserved corrugated pore passage (5) and the prestressed tendon pore passage (8) by embedding a metal corrugated pipe and a PVC pipe;

step three, stacking all the prefabricated sections (4) in sequence, and enabling the prestressed tendons to penetrate through the prestressed tendon pore passages (8) in the center positions of all the sections; in the assembling process, epoxy resin is uniformly brushed on the joint surfaces between the bottommost section and the bearing platform and between two adjacent sections;

tensioning the unbonded prestressed tendons (7) and sealing the anchor grooves 3 in the upper parts of the prestressed tendons;

putting the through longitudinal bars (6) into the corrugated pore canal (5) of the pier, and enabling each through longitudinal bar to be located at the center of the pore canal, wherein the through longitudinal bars comprise common steel bars and finish-rolled twisted steel bars; for the high pier, a welding joint or a steel bar mechanical connecting joint is adopted to lengthen a common steel bar, and a spiral connector is adopted to lengthen a finish-rolled twisted steel bar;

step six, using cement-based grouting material to perform grouting on the corrugated pore channel (5); a plurality of grouting holes are uniformly arranged along the vertical direction of the pier body, and grouting operation is carried out by adopting a segmented grouting mode and/or a pressure grouting method.

2. The construction method of the common steel bar and finish rolled twisted steel bar mixed reinforcement assembling pier as claimed in claim 1, wherein: the assembling pier body (2) is composed of one or more than one prefabricated sections (4), the through longitudinal reinforcements (6) are formed by mixing two types of reinforcements, namely common reinforcements and finish-rolled threaded reinforcements, and are connected with the concrete bearing platform (1) and the assembling pier bodies (2) together to form a complete pier system together with unbonded prestressed reinforcements (7), other steps are unchanged under the working condition that the assembling pier body (2) only has one prefabricated section (4), and the third step is that the bottoms of the prefabricated sections (4) are stacked on the concrete bearing platform (1) to enable the prestressed reinforcements to penetrate through prestressed reinforcement ducts (8) in the center positions of the sections; in the assembling process, epoxy resin is uniformly coated on the splicing surface between the prefabricated segment (4) and the bearing platform.

3. The construction method of the common steel bar and finish rolled twisted steel bar mixed reinforcement assembling pier as claimed in claim 1, wherein: assemble pier shaft (2) and constitute by two or two above prefabricated sections (4), link up and indulge muscle (6) and form by two kinds of reinforcing bars mixes of ordinary reinforcing bar and finish rolling twisted steel to together with unbonded prestressed reinforcement (7) connect concrete cushion cap (1) and each assemble pier shaft (2) and become complete pier system, ordinary reinforcing bar and finish rolling twisted steel only link up and assemble a plurality of sections of pier shaft (2) lower part, and do not arrange along whole pier shaft.

4. The construction method of the common steel bar and finish rolled twisted steel bar mixed reinforcement assembling pier as claimed in claim 1, wherein: the reinforcement ratio of the common steel bars to the finish-rolled twisted steel bars is 0.5-2.0, and the common steel bars and the finish-rolled twisted steel bars are arranged at intervals and/or symmetrically in a plane.

5. The splicing pier for the mixed reinforcement of the common steel bars and the finish rolled threaded steel bars according to claim 1, is characterized in that: the upper end surface and the lower end surface of the prefabricated segment (4) are flat or are provided with single or a plurality of shear keys.

6. The construction method of the common steel bar and finish rolled twisted steel bar mixed reinforcement assembling pier as claimed in claim 1, wherein: the types of common steel bars used for penetrating the longitudinal bars (6) are HRB400, HRB500, HRBF400, HRBF500, HRB400E, HRB500E, HRBF400E or HRBF 500E; the type of finish-rolled threaded steel bar used for the penetrating longitudinal bar 6 is PSB785, PSB830, PSB930, PSB1080 or PSB 1200.

7. The construction method of the common steel bar and finish rolled twisted steel bar mixed reinforcement assembling pier as claimed in claim 1, wherein: reserved corrugationThe pore canal (5) adopts a pre-embedded circular metal corrugated pipe, and the diameter of the corrugated pipe is (2 to 3)dWhereindThe diameter of the through longitudinal rib.

8. The construction method of the common steel bar and finish rolled twisted steel bar mixed reinforcement assembling pier as claimed in claim 1, wherein: the length of the corrugated pipe embedded in the bearing platform is not less than 36d，dThe diameter of the through longitudinal rib.

9. The construction method of the common steel bar and finish rolled twisted steel bar mixed reinforcement assembling pier as claimed in claim 1, wherein: the lower end of the finish-rolled threaded steel bar is provided with a nut anchorage matched with the bar material.

10. The construction method of the common steel bar and finish rolled twisted steel bar mixed reinforcement assembling pier as claimed in claim 1, wherein: the type of the prestressed tendon used by the unbonded prestressed tendon 7 is a steel strand, a prestressed twisted steel bar or an FRP prestressed tendon.