A lightweight assembled partially prestressed concrete hollow column pier structure and its construction technology

Abstract

The present invention discloses a lightweight assembled partially prestressed concrete hollow column pier structure, including a cap beam, a pier column and a base arranged in sequence from top to bottom; the cap beam and the base are cast in situ, and the pier column is prefabricated; the UHPC wet joint and partially prestressed segment joint technology are adopted to improve the joint stress performance, pier ductility and seismic resistance, and facilitate construction; by adopting a plurality of segment continuous and rapid construction technology, the height of the segment is reduced, thereby significantly reducing the deadweight of the prefabricated component, greatly facilitating transportation and rapid installation, and shortening the construction period. The present invention discloses a construction process, which has the advantages of convenient construction, good stress performance, good durability, good economy, energy saving and environmental protection, etc., is suitable for the assembled construction of high piers of bridges, and has broad prospects for promotion and application.

Description

Technical Field

[0001] The present invention relates to the field of bridge engineering, and more specifically, to a lightweight assembled partially prestressed concrete hollow column pier structure and a construction process thereof. Background Art

[0002] With the continuous development of my country's transportation infrastructure, higher and higher requirements have been put forward for bridge construction. The standardization, assembly and factory construction of bridge components have gradually become a consensus. Therefore, prefabrication and assembly technology that facilitates standardization, assembly and factory construction has developed rapidly and become the mainstream development direction of bridge construction.

[0003] At present, the prefabrication and assembly technology of bridge superstructures in my country has been developed to a relatively mature level, and the superstructures of small and medium-span bridges are basically constructed by assembly. For the substructure, the prefabrication and assembly technology is in the exploratory stage, and some urban bridges, cross-sea bridges, and highway bridges with conditions have gradually carried out the application and research of prefabrication and assembly pier technology.

[0004] However, in view of the current technology, prefabricated bridge piers are basically applied to shorter bridge piers and cannot be widely used in high piers. In addition, the cost of prefabricated bridge piers is generally higher than that of cast-in-place bridge piers. The current technical limitations are mainly: 1. The joint structure is complex or the construction is difficult, so the design generally tries to reduce the joints as much as possible. The height of the prefabricated segments is generally large, and the weight of the prefabricated segments is large, which is not convenient for transportation and installation, especially for high pier bridges in mountainous areas. 2. In order to ensure the reliable force of the pier body, most prefabricated bridge piers currently use dry joints or adhesive joints, and grouting sleeves to connect steel bars. This technology requires precise docking of the segments, and matching prefabrication is required between the segments. It has high construction requirements, especially for high piers. It is difficult to control the verticality of the pier body. In addition, the large amount of grouting sleeves also increases the project cost. 3. In order to overcome the shortcomings of dry joints or adhesive joints, some prefabricated bridge piers use cast-in-place wet joint connection technology, which eliminates the need for steel bar connection and facilitates the adjustment of the verticality of the pier body. However, the steel bars in the wet joints are staggered, and the cast-in-place joint materials are used. The bonding of concrete or UHPC, etc. and steel bars realizes continuous stress on the pier body, and the stress performance of the joints is relatively poor. For high piers, the stress is large and the number of joints is large. The stress reliability of the pier body is reduced by using this joint technology. In addition, wet joints rely on bonding to transmit force, so the height of wet joints is generally large, and the material consumption is large, which increases the project cost. At the same time, since it is necessary to wait for the wet joints to reach the design strength before the next section can be constructed during the construction process, there are many joints for high piers and the construction period is very long; 4. Currently, prestressed technology is rarely used in prefabricated bridge piers. The main reason is that prestressed construction is relatively complicated, especially for the extension of multiple sections of prestressed steel bars, the construction process is more complicated and the construction period is longer. In addition, compared with reinforced concrete piers, prestressed concrete piers have reduced ductility and relatively poor seismic performance, which is particularly unfavorable for high piers.

[0005] Therefore, in view of the above situation, how to improve the structure and construction technology of bridge piers to enhance the construction convenience, stress resistance, durability and economy, so that the bridge piers can be more suitable for the assembly construction of high bridge piers, has become an important technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0006] The present invention discloses a lightweight assembled partially prestressed concrete hollow column pier structure and a construction process thereof, wherein the lightweight assembled partially prestressed concrete hollow column pier structure comprises a cap beam, a pier column and a base arranged in sequence from top to bottom; the cap beam and the base are cast in situ, and the pier column is prefabricated; The pier is a hollow column structure, which includes a plurality of hollow segments, and adjacent segments are connected by UHPC wet joints; a prestressed steel bar embedded pipe is provided on the segment, and prestressed coarse steel bars are provided in the prestressed steel bar embedded pipe; two prestressed steel bar embedded pipes between two adjacent segments are butt-jointed by a snap-fit ​​connection sleeve, and two prestressed coarse steel bars in the two prestressed steel bar embedded pipes are connected by a connector.

[0007] Preferably, there are two piers, which are connected by a transverse tie beam; the transverse tie beam is a precast concrete component, and its end is connected to the pier by a UHPC wet joint.

[0008] Preferably, the pier is a circular tubular column structure with a circular cross-section; the transverse tie beam is connected to the segment on the pier; the interior of the segment docked with the transverse tie beam is a solid structure and is provided with embedded steel components, and the embedded steel components are connected to the transverse tie beam.

[0009] Preferably, the pier is a box-column structure with a square cross-section; the transverse tie beam includes two tie beam plates, and the tie beam plates are connected to the segments on the pier.

[0010] Preferably, a top steel plate is provided inside the segment located at the top of the pier, a top solid segment is connected to the top steel plate, and top connecting steel bars are embedded in the top solid segment; the prestressed coarse steel bars on the segment located at the top of the pier extend into the cap beam and are connected to the cap beam, and the top connecting steel bars extend into the cap beam and are connected to the cap beam.

[0011] Preferably, a bottom solid section is provided on the segment located at the bottom of the pier, and a bottom steel plate is pre-embedded on the bottom solid section; the base and the segment located at the bottom of the pier are connected by a cast-in-place concrete wet joint; bottom connecting steel bars and bottom prestressed steel bars are pre-embedded in the base, the connecting steel bars are butt-jointed with the bottom steel plate, and the bottom prestressed steel bars are butt-jointed with the prestressed coarse steel bars on the segment located at the bottom of the pier.

[0012] A lightweight assembled partially prestressed concrete hollow column pier structure and a construction process thereof, comprising the following steps: Step S1: pouring the pile to break the cast-in-place section of the pile head and pre-embedding the cast-in-place section prestressed coarse steel bars, cast-in-place wet joint connecting steel bars and temporary connecting fixing steel plates; Step S2: installing the first section of prestressed coarse steel bars, and connecting them with the pre-buried cast-in-place section of prestressed coarse steel bars using connectors; Step S3: installing the first section of the prefabricated pier body, positioning and adjusting the jack, and installing the prestressed thick steel bar pipe connection sleeve; Step S4: welding and connecting the fixed steel plates, and removing the adjusting jacks; Step S5: installing the wet joint formwork and pouring wet joint concrete; Step S6: installing the second section of the prefabricated pier body and adjusting the positioning of the jack; Step S7: installing the temporary fixing structure of the second segment of the prefabricated pier body and removing the adjusting jack; Step S8: installing the prestressed thick steel bar pipe connection sleeve, installing the joint UHPC wet joint template, and pouring the UHPC wet joint; Step S9: repeat steps S6 to S8, install the third segment of the prefabricated pier, and cast the UHPC wet joint; Step S10: After the cast UHPC wet joint reaches the design strength, the prestressed coarse steel bars are tensioned and anchored; Step S11: removing all temporary fixings and wet joint templates of the segments; Step S12: installing the horizontal tie beam; Step S13: Install and connect prestressed thick steel bars; Step S14: Repeat steps S3 to S12 to install the remaining pier segments until the installation of the last segment (pier top segment) and the anchoring of the prestressed coarse steel bars are completed; Step S15: installing the bottom formwork of the wet-jointed solid section of the pier top, installing the steel bars, and pouring the solid section concrete; Step S16: constructing concrete cap beam.

[0013] Preferably, in step S12, the installation construction steps of the transverse tie beam are as follows: Step S12-1: hoisting prefabricated horizontal tie beams; Step S12-2: The horizontal tie beam is in place and the angle steel is welded and connected; Step S12-3: Install wet joint steel bars and cast wet joint UHPC.

[0014] Preferably, the segments of the prefabricated pier body are installed by crane or tower crane, and the segments are temporarily connected and fixed by bolt-locked H-shaped steel, which meets the stress and stability requirements during the construction stage, and can realize the tensioning and anchoring of prestressed coarse steel bars after the continuous construction of several segments, thus shortening the construction period; The temporary H-steel connection and fixing structure includes locking bolts, inner H-steel and outer H-steel. The inner H-steel is arranged inside the segment, and the outer H-steel is arranged outside the segment. Openings are reserved on the segment for inserting locking bolts. After the locking bolts are pulled and anchored, the inner H-steel and the outer H-steel inside and outside the segment are locked with the two adjacent segments. Multiple pairs of inner H-steel and outer H-steel are arranged along the segment to lock the segments of the two adjacent piers into a whole force-bearing state, so as to ensure that the pier structure has sufficient bearing capacity and stability during the construction process before the joints of the segment are constructed or reach sufficient strength.

[0015] Preferably, the UHPC wet joint casting formwork between the segments adopts a unitized assembled formwork, and the unitized assembled formwork is positioned and fastened by a temporary connection fixing structure; and a grouting port is provided in the inner mold of the unitized assembled formwork.

[0016] The lightweight assembled partially prestressed concrete hollow column pier structure and its construction process provided by the present invention are based on the existing prefabricated bridge pier technology, and propose to use UHPC wet joints and partially prestressed segment joint technology to improve the joint stress performance, pier column ductility and seismic resistance, and facilitate construction; by adopting multiple segment continuous and rapid construction technology, the height of the segment is reduced, thereby significantly reducing the self-weight of the prefabricated component, greatly facilitating transportation and rapid installation, and shortening the construction period. Compared with the conventional cast-in-place height, the lightweight assembled partially prestressed concrete hollow column pier structure of the present invention saves material consumption and has a lower project cost. The construction process of the present invention has the advantages of convenient construction, good stress performance, good durability, good economy, energy saving and environmental protection, etc. It is suitable for the assembly construction of high bridge piers and has broad prospects for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a front view of the pier structure of the present invention; Figure 2 is a side view of the pier structure of the present invention; Figure 3 It is a front view of another embodiment (box-column structure) of the present invention; Figure 4It is a side view of another embodiment (box-column structure) of the present invention; Figure 5 It is a schematic diagram of the installation structure of the transverse tie beam of the pier structure of the present invention; Figure 6 It is a schematic diagram of the installation structure of the horizontal tie beam of another embodiment (box column structure) of the present invention; Figure 7 It is a structural schematic diagram of a segment of the pier structure of the present invention; Figure 8 It is a schematic diagram of the connection structure between the segments of the pier structure of the present invention; Fig. 9 It is a schematic diagram of the connection structure between the segments and the transverse tie beams of the pier structure of the present invention; Fig.10 It is a schematic diagram of the connection structure between the segment and the transverse tie beam of another embodiment (box column structure) of the present invention; Fig.11 is a schematic diagram of step S1 of the present invention; Fig.12 is a schematic diagram of step S2 of the present invention; Fig.13 is a schematic diagram of step S3 of the present invention; Fig.14 is a schematic diagram of step S4 of the present invention; Fig.15 is a schematic diagram of step S5 of the present invention; Fig.16 is a schematic diagram of step S6 of the present invention; Fig.17 is a schematic diagram of step S7 of the present invention; Fig.18 is a schematic diagram of step S8 of the present invention; Fig.19 is a schematic diagram of step S9 of the present invention; Fig. 20 is a schematic diagram of step S10 of the present invention; Fig.21 is a schematic diagram of step S11 of the present invention; Fig. 22 is a schematic diagram of step S12 of the present invention; Fig.23 is a schematic diagram of step S13 of the present invention; Fig.24 is a schematic diagram of step S14 of the present invention; Fig.25 is a schematic diagram of step S15 of the present invention; Fig.26 is a schematic diagram of step S16 of the present invention; Fig. 27 It is a schematic diagram of the temporary connection and fixing structure of the H-beam of the present invention; Fig.28 It is a schematic diagram of the installation structure of an embodiment of the H-beam temporary connection and fixing structure of the present invention; Fig.29 It is a schematic diagram of the installation structure of another embodiment of the H-beam temporary connection and fixing structure of the present invention; The marks in the drawings are as follows: 1--cap beam, 2--pier column, 201--segment, 202--UHPC wet joint, 203--prestressed steel embedded pipe, 204--prestressed coarse steel bar, 205--snap-on sleeve, 206--connector, 207--embedded steel member, 208--top solid section, 209--bottom solid section, 3--base, 4--transverse tie beam, 401--tie beam plate, 5--cast-in-place section of pile top, 6--cast-in-place prestressed coarse steel bar, 7--cast-in-place Pour wet joint connecting steel bars, 8--fixed steel plate, 9--first section of prestressed coarse steel bars, 10--first segment, 11--jack positioning adjustment, 12--wet joint formwork, 13--wet joint concrete, 14--second segment, 15--temporary fixing structure, 16--joint UHPC wet joint formwork, 17--third segment, 18--H-steel temporary connection and fixing structure, 1801--locking bolts, 1802--inner H-steel, 1803--outer H-steel. DETAILED DESCRIPTION

[0019] The present invention discloses a lightweight assembled partially prestressed concrete hollow column pier structure and a construction process thereof. Based on the existing prefabricated bridge pier technology, it proposes to use UHPC wet joints and partially prestressed segment joint technology to improve the joint force performance, pier column ductility and seismic resistance, and facilitate construction; it proposes a multi-segment continuous and rapid construction technology to reduce the height of the prefabricated segments, thereby significantly reducing the deadweight of the prefabricated components, greatly facilitating transportation and rapid installation, and shortening the construction period. Compared with conventional cast-in-place height, the lightweight assembled partially prestressed concrete hollow column pier structure of the present invention saves material consumption and has a lower project cost. The lightweight assembled partially prestressed concrete hollow column pier structure of the present invention and its construction process have the advantages of convenient construction, good force performance, good durability, good economy, energy saving and environmental protection, etc. It is suitable for the assembly construction of high bridge piers and has broad prospects for promotion and application.

[0020] The following is a clear and detailed description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figures 1 to 26 The present invention discloses a lightweight assembled partially prestressed concrete hollow column pier structure and a construction process thereof, wherein the lightweight assembled partially prestressed concrete hollow column pier structure comprises a cap beam 1, a pier column 2 and a base 3 arranged in sequence from top to bottom; the cap beam 1 and the base 3 are cast-in-place, and the pier column 2 is prefabricated; The pier 2 is a hollow column structure, which includes a plurality of hollow segments 201. Adjacent segments 201 are connected by UHPC wet joints 202. A prestressed steel bar embedded pipe 203 is provided on the segment 201, and a prestressed coarse steel bar 204 is provided in the prestressed steel bar embedded pipe 203. The two prestressed steel bar embedded pipes 203 between two adjacent segments 201 are butt-jointed by a snap-fit ​​connection sleeve 205, and the two prestressed coarse steel bars 204 in the two prestressed steel bar embedded pipes 203 are connected by a connector 206.

[0022] The technical problem to be solved by the present invention is: in view of the problems existing in the current prestressed assembled pier technology, the present invention provides a lightweight assembled partially prestressed concrete hollow column pier structure and its construction process, which has the advantages of convenient construction, good stress performance, good durability, good economy, energy saving and environmental protection, and is particularly suitable for high pier bridges in mountainous areas.

[0023] In order to achieve the above object, the present invention adopts the following technical solutions: Adopt UHPC wet joint technology: The joints between segments 201 and the joints between pier 2 and transverse tie beam 4 are all cast-in-place UHPC wet joints. UHPC material has good compression resistance, tensile strength, bonding performance and working performance (good fluidity and self-compacting). Adopting UHPC wet joints can effectively reduce the size of wet joints, significantly improve the force of joints, and facilitate construction; Partial prestressing technology: adopt reasonable prestressing intensity, and try to reduce the tensile stress of prestressed steel bars as much as possible under the premise that the prestressed steel bars reach yield under the ultimate bearing capacity state, so as to fully exert the strength of prestressed steel bars and ensure that the piers have good ductility and seismic performance.

[0024] Pier 2 adopts a multi-segment 201 structure and a multi-segment 201 continuous and rapid construction technology: temporary construction measures are used to meet the stress and stability requirements of the pier segment 201 during the construction process. The segment 201 construction does not need to wait for the joint material to cure to reach the design strength, thereby achieving continuous and rapid construction of the multi-segment 201. After adopting the multi-segment continuous and rapid construction technology, more joints can be set on pier 2, thereby reducing the height of the prefabricated segment 201 and the weight of the prefabricated components.

[0025] Prefabricated cross beam 4 rapid construction technology: rapid construction of prefabricated cross beams is achieved through embedded components.

[0026] Specifically, the lightweight assembled high pier structure of the embodiment of the present invention is composed of a cast-in-place base 3, a prefabricated pier column 2 and a cast-in-place cap beam 1. The pier column 2 is a hollow column structure. The pier column 2 can be a round tube column or a box column according to the force requirements. Each pier column 2 is formed by splicing a number of prefabricated concrete segments 201. The segments 201 are connected by UHPC wet joints 202, and through-through prestressed coarse steel bars 204 are provided to strengthen the connection between the segments 201 and improve the bearing capacity of the pier column. The prestressed steel bars are connected by connectors 206, and the prestressed steel bar embedded pipes 203 of the prestressed coarse steel bars 204 are connected by snap-fit ​​sleeves.

[0027] Specifically, the splicing combination between the two segments 201 is completed by a UHPC wet joint 202. Compared with traditional concrete pouring, this embodiment uses UHPC as the connecting material. Since UHPC uses materials such as fine bone with optimized grading, high-grade cement, ultrafine high-activity mineral admixtures, micro-bead ultrafine powder and special organic chemical additives, a multi-filling effect is produced in the UHPC structural system, forming a dense structure, reducing microscopic defects, and greatly optimizing the internal microporous structure, thereby achieving ultra-high mechanical properties, durability and construction performance. The performance of the connector made of UHPC material is higher, reaching 140-160 MPa. In addition, the brittleness of the substrate can be improved and the toughness can be improved by adding steel fibers or a variety of engineering fibers to the UHPC material.

[0028] In this embodiment, the segment 201 is a hollow structure, and a plurality of prestressed steel bar embedded pipes 203 are arranged along the side wall of the segment 201, and a prestressed coarse steel bar 204 is arranged in each prestressed steel bar embedded pipe 203. Between two adjacent segments 201, the prestressed steel bar embedded pipes 203 on the two segments 201 are arranged in a one-to-one matching manner, and the two relative prestressed steel bar embedded pipes 203 are butted together through a snap-fit ​​connection sleeve 205. The snap-fit ​​connection sleeve 205 is easy to install and can quickly splice the two prestressed steel bar embedded pipes 203 together. Before the socket connection, the prestressed coarse steel bar 204 in the prestressed steel bar embedded pipe 203 needs to be butted with the prestressed coarse steel bar 204 on the adjacent segment 201, and the two prestressed coarse steel bars 204 are quickly butted together using a connector 206.

[0029] Furthermore, in order to improve the structural strength of the segment 201 , a plurality of longitudinal reinforcing ribs are provided on the outer layer of the side wall of the segment 201 , and a plurality of transverse annular stirrups are provided for reinforcement to reduce the occurrence of surface collapse of the segment 201 .

[0030] Preferably, there are two piers 2, and the two piers 2 are connected by a transverse tie beam 4; the transverse tie beam 4 is a precast concrete component, and its end is connected to the pier 2 by a UHPC wet joint 202. In this embodiment, when two or more bridge piers are provided, adjacent piers 2 are connected in the horizontal direction by a transverse tie beam 4. The transverse tie beam 4 is also a precast concrete component, and its end is butted against the side of the pier 2 to fix the UHPC wet joint 202, which is also made of UHPC material.

[0031] Preferably, the pier is a circular tubular column structure with a circular cross-section; the transverse tie beam 4 is connected to the segment 201 on the pier; the interior of the segment 201 connected to the transverse tie beam 4 is a solid structure and is provided with an embedded steel component 207, and the embedded steel component 207 is connected to the transverse tie beam 4.

[0032] In this embodiment, the entire pier is a cylindrical structure, that is, a circular structure in cross section. Since the joint of the curved surface structure requires more contact points, this embodiment adopts an internal solid structure in the corresponding segment 201, and an embedded steel member 207 is set in the solid structure, and the embedded steel member 207 is connected to the horizontal tie beam 4, and then the same wet joint is used for reinforcement at the joint.

[0033] Preferably, the pier is a box-column structure with a square cross section; the transverse tie beam 4 includes two tie beam plates 401, and the tie beam plates 401 are connected to the segments 201 on the pier. In this embodiment, the pier is a box-column structure, that is, the cross section is square. In this structure, the contact surface of the segment 201 is large, and a stable connection effect can be maintained without providing a solid segment.

[0034] Preferably, a top steel plate is provided inside the segment 201 located at the top of the pier 2, a top solid segment 208 is connected to the top steel plate, and a top connecting steel bar is embedded in the top solid segment 208; the prestressed coarse steel bar 204 on the segment 201 located at the top of the pier 2 extends into the cap beam 1 and is connected to the cap beam 1, and the top connecting steel bar extends into the cap beam 1 and is connected to the cap beam 1. In this embodiment, the pier is composed of a plurality of segments 201, wherein a top steel plate is provided inside the segment 201 located at the top, and a top solid segment 208 is provided on the top steel plate, and a top connecting steel bar is embedded in the top solid segment 208 so as to dock with the cap beam 1. The top connecting steel bar is inserted into the cap beam 1 and fixedly connected to the cap beam 1.

[0035] Preferably, a bottom solid section 209 is provided on the segment 201 at the bottom of the pier 2, and a bottom steel plate is pre-embedded on the bottom solid section 209; the base 3 and the segment 201 at the bottom of the pier 2 are connected by a cast-in-place concrete wet joint; bottom connecting steel bars and bottom prestressed steel bars are pre-embedded in the base 3, the connecting steel bars are butted with the bottom steel plate, and the bottom prestressed steel bars are butted with the prestressed coarse steel bars 204 on the segment 201 at the bottom of the pier 2. In this embodiment, the pier is composed of a plurality of segments 201, wherein a segment 201 at the bottom has a bottom solid section 209 inside, and a bottom steel plate is pre-embedded in the bottom solid section 209 to butt with the connecting steel bars on the base 3, and the bottom prestressed steel bars on the base 3 are butted one by one with the prestressed coarse steel bars 204 on the corresponding segment 201.

[0036] A lightweight assembled partially prestressed concrete hollow column pier structure and a construction process thereof, comprising the following steps: Step S1: pouring the pile to break the cast-in-place section 5 of the pile head and pre-embed the cast-in-place section prestressed coarse steel bars 6204, cast-in-place wet joint connecting steel bars 7 and temporary connecting fixing steel plates 8; Step S2: Install the first section of prestressed coarse steel bars 9 and connect them to the embedded cast-in-place section of prestressed coarse steel bars 6204 using connector 206; in this step, when docking, the first section of prestressed coarse steel bars 9 can be enclosed and fixed using a forming frame to ensure precise docking and improve docking installation efficiency.

[0037] Step S3: Install the first segment 10 of the prefabricated pier body, position and adjust the jack 11, and install the prestressed coarse steel bar 204 pipe connecting sleeve; when installing the first segment 10 of the pier body, a jack can be set between the segment 201 and the cast-in-place segment 5 of the pile top broken pile head, and the jack can be used to adjust the position and distance between the two to better install the connecting sleeve, so that the connection between the prestressed coarse steel bar 204 pipes is more accurate.

[0038] Step S4: welding and connecting the fixed steel plate 8, and removing the adjusting jack; Step S5: installing the wet joint template 12 and pouring the wet joint concrete 13; Step S6: installing the second section 14 of the prefabricated pier body and adjusting the positioning of the jack 11; Step S7: Install the temporary fixing structure 15 of the second segment 14 of the prefabricated pier body and remove the adjusting jack; Step S8: installing the prestressed coarse steel bar 204 pipe connection sleeve, installing the joint UHPC wet joint template 16, and casting the UHPC wet joint 202; Step S9: repeating steps S6 to S8, installing the third prefabricated pier section 17, and casting the UHPC wet joint 202; Step S10: After the cast UHPC wet joint 202 reaches the design strength, the prestressed coarse steel bars 204 are tensioned and anchored; Step S11: removing the temporary fixing and wet joint templates of all segments 201; Step S12: installing the horizontal tie beam 4; Step S13: installing and connecting the prestressed thick steel bars 204; Step S14: repeat steps S3 to S12 to install the remaining pier segments 201 until the installation of the last segment 201 (the pier top segment) and the anchoring of the prestressed coarse steel bars 204 are completed; Step S15: installing the bottom formwork of the wet-jointed solid section of the pier top, installing the steel bars, and pouring the solid section concrete; Step S16: construct the concrete cap beam 1.

[0039] The construction process of the present invention has the advantages of convenient construction, good stress performance, good durability, good economy, energy saving and environmental protection, etc., and is particularly suitable for high pier bridges in mountainous areas. This construction process adopts UHPC wet joint technology. UHPC materials have good compression resistance, tensile resistance, bonding performance and working performance (good fluidity and self-compacting). The use of UHPC wet joints can effectively reduce the size of wet joints, significantly improve the stress of joints, and facilitate construction. In addition, by adopting a reasonable prestressing force, the prestressing stress of the prestressed steel bars is reduced as much as possible under the premise that the prestressed steel bars reach yield in the ultimate bearing capacity state, so as to achieve both full utilization of the strength of the prestressed steel bar material and ensure that the pier body has good ductility and seismic resistance. Finally, in terms of improving the construction speed, a rapid construction technology of multi-segment 201 splicing and installation is adopted. Temporary construction measures are taken to meet the stress and stability requirements of the pier body segment 201 during the construction process. The construction of the segment 201 does not need to wait for the joint material to cure to reach the design strength, thereby achieving continuous and rapid construction of multiple segments 201. After adopting the multi-segment continuous and rapid construction technology, more joints can be set in the pier column 2, thereby reducing the height of the prefabricated segment 201 and the weight of the prefabricated components.

[0040] Preferably, in step S12, the installation construction steps of the horizontal tie beam 4 are as follows: Step S12-1: hoisting the prefabricated horizontal tie beam 4; Step S12-2: The horizontal tie beam 4 is in place and the angle steel is welded and connected; Step S12-3: Install wet joint steel bars and cast wet joint UHPC.

[0041] Preferably, the segments 201 of the prefabricated pier body are installed by a crane or a tower crane, and a bolt-locked H-shaped steel temporary connection fixing structure 18 is used between the segments 201 to meet the stress and stability requirements during the construction phase, and the prestressed coarse steel bars 204 can be tensioned and anchored after the continuous construction of several segments 201, thereby shortening the construction period. In this embodiment, the height of the pier body segments 201 is controlled to achieve lightweight prefabricated components, and the prefabricated pier body segments 201 are installed by a crane or a tower crane, and a bolt-locked H-shaped steel temporary connection fixing structure 18 is used between the segments 201, which meets the stress and stability requirements during the construction phase, and the prestressed coarse steel bars 204 can be tensioned and anchored after the continuous construction of several segments 201, thereby shortening the construction period; The H-steel temporary connection and fixing structure 18 includes locking bolts 1801, inner H-steel 1802 and outer H-steel 1803. The inner H-steel 1802 is arranged inside the segment, and the outer H-steel 1803 is arranged outside the segment. Openings are reserved on the segment and used to insert the locking bolts 1801. After the locking bolts 1801 are pulled and anchored, the inner H-steel 1802 and the outer H-steel 1803 inside and outside the segment are locked with the two adjacent segments. Multiple pairs of inner H-steel 1802 and outer H-steel 1803 are arranged along the segment to lock the segments of the two adjacent piers to form a whole force-bearing structure, so as to ensure that the pier structure has sufficient bearing capacity and stability during the construction process before the joints of the segment are not constructed or do not reach sufficient strength.

[0042] Preferably, the UHPC wet joint casting template between the segments 201 adopts a unitized assembled template, which is positioned and fastened by a temporary connection fixing structure; the inner mold of the unitized assembled template is provided with a grouting port. In this embodiment, the unitized assembled template is easier to install and disassemble, and the grouting port is provided on the inner mold to avoid grouting on the outer side to affect the appearance of the pier 2.

[0043] The lightweight assembled partially prestressed concrete hollow column pier structure and its construction process provided by the present invention are based on the existing prefabricated bridge pier technology, and propose to use UHPC wet joints and partially prestressed segment joint technology to improve the joint stress performance, pier ductility and seismic resistance, and facilitate construction; by adopting multiple segment continuous and rapid construction technology, the height of the segment is reduced, thereby significantly reducing the self-weight of the prefabricated component, greatly facilitating transportation and rapid installation, and shortening the construction period. Compared with the conventional cast-in-place height, the lightweight assembled partially prestressed concrete hollow column pier structure of the present invention saves material consumption and has a lower project cost. The construction process of the present invention has the advantages of convenient construction, good stress performance, good durability, good economy, energy saving and environmental protection, etc. It is suitable for the assembly construction of high bridge piers and has broad prospects for promotion and application.

Claims

1. A lightweight assembled partially prestressed concrete hollow column pier structure, characterized in that: It comprises a cap beam (1), a pier column (2) and a base (3) which are arranged in sequence from top to bottom; the cap beam and the base are both cast in situ, and the pier column is prefabricated; The pier column is a hollow column structure, which includes a plurality of hollow segments (201), and adjacent segments are connected by UHPC wet joints (202); the segments are provided with prestressed steel bar embedded pipes (203), the prestressed steel bar embedded pipes between two adjacent segments are butt-jointed by a snap-fit ​​connection sleeve (205), and two prestressed thick steel bars in the two prestressed steel bar embedded pipes are connected by a connector (206).

2. The lightweight assembled partially prestressed concrete hollow column pier structure according to claim 1 is characterized in that: There are two piers, and the two piers are connected by a transverse tie beam (4); the transverse tie beam is a prefabricated concrete component, and its end is connected to the pier by a UHPC wet joint.

3. The lightweight assembled partially prestressed concrete hollow column pier structure according to claim 2 is characterized in that: The pier is a circular tube column structure with a circular cross section; the transverse tie beam is connected to a segment on the pier; the interior of the segment connected to the transverse tie beam is a solid structure and is provided with an embedded steel component (207), and the embedded steel component is connected to the transverse tie beam.

4. The lightweight assembled partially prestressed concrete hollow column pier structure according to claim 2 is characterized in that: The pier is a box-column structure with a square cross section; the transverse tie beam comprises two tie beam plates (401), and the tie beam plates are connected to the segments on the pier.

5. The lightweight assembled partially prestressed concrete hollow column pier structure according to claim 1 is characterized in that: A top steel plate is provided inside the segment located at the top of the pier column, to which a top solid segment (208) is connected, and top connecting steel bars are embedded in the top solid segment; the prestressed coarse steel bars on the segment located at the top of the pier column extend into the cap beam and are connected to the cap beam, and the top connecting steel bars extend into the cap beam and are connected to the cap beam.

6. The lightweight assembled partially prestressed concrete hollow column pier structure according to claim 1 is characterized in that: A bottom solid section (209) is provided on the segment located at the bottom of the pier column, and a bottom steel plate is pre-embedded on the bottom solid section; the base and the segment located at the bottom of the pier column are connected by a cast-in-place concrete wet joint; bottom connecting steel bars and bottom prestressed steel bars are pre-embedded in the base, the connecting steel bars are butt-jointed with the bottom steel plate, and the bottom prestressed steel bars are butt-jointed with the prestressed coarse steel bars on the segment located at the bottom of the pier column.

7. The construction process of the lightweight assembled partially prestressed concrete hollow column pier structure according to any one of claims 1 to 6, characterized in that: The following steps are included: Step S1: pouring the pile to break the cast-in-place section of the pile head (5) and pre-embedding the cast-in-place section prestressed coarse steel bars (6), cast-in-place wet joint connecting steel bars (7) and temporary connecting fixing steel plates (8); Step S2: installing the first section of prestressed coarse steel bars (9), and connecting them to the pre-buried cast-in-place section of prestressed coarse steel bars using connectors; Step S3: installing the first section of the prefabricated pier body (10), positioning and adjusting the jack (11), and installing the prestressed thick steel bar pipe connection sleeve; Step S4: welding and connecting the fixed steel plates, and removing the adjusting jacks; Step S5: installing the wet joint formwork (12) and pouring the wet joint concrete (13); Step S6: installing the second section (14) of the prefabricated pier body and adjusting the positioning of the jack; Step S7: installing the temporary fixing structure (15) of the second segment of the prefabricated pier shaft and removing the adjusting jack; Step S8: installing the prestressed thick steel bar pipe connection sleeve, installing the joint UHPC wet joint template (16), and casting the UHPC wet joint; Step S9: repeating steps S6 to S8, installing the third prefabricated pier section (17), and casting the UHPC wet joint; Step S10: After the cast UHPC wet joint reaches the design strength, the prestressed coarse steel bars are tensioned and anchored; Step S11: removing all temporary fixings and wet joint templates of the segments; Step S12: installing the horizontal tie beam; Step S13: Install and connect prestressed thick steel bars; Step S14: repeat steps S3 to S12 to install the remaining pier segments until the installation of the last segment (pier top segment) and the anchoring of the prestressed coarse steel bars are completed; Step S15: installing the bottom formwork of the wet-jointed solid section of the pier top, installing the steel bars, and pouring the solid section concrete; Step S16: constructing concrete cap beam.

8. The lightweight assembled partially prestressed concrete hollow column pier structure and its construction process according to claim 7 is characterized in that: In step S12, the installation and construction steps of the transverse tie beam are as follows: Step S12-1: hoisting prefabricated horizontal tie beams; Step S12-2: The horizontal tie beam is in place and the angle steel is welded and connected; Step S12-3: Install wet joint steel bars and cast wet joint UHPC.

9. The lightweight assembled partially prestressed concrete hollow column pier structure and its construction process according to claim 7, characterized in that: The segments of the prefabricated pier body are installed by crane or tower crane, and the segments are temporarily connected and fixed by bolt-locked H-shaped steel (18), which meets the stress and stability requirements during the construction stage. It is possible to tension and anchor the prestressed coarse steel bars after the continuous construction of several segments, thus shortening the construction period. The H-shaped steel temporary connection and fixing structure includes locking bolts (1801), inner H-shaped steel (1802) and outer H-shaped steel (1803), wherein the inner H-shaped steel is arranged inside the segment and the outer H-shaped steel is arranged outside the segment; holes are reserved on the segment for inserting locking bolts, and after the locking bolts are pulled and anchored, the inner H-shaped steel and the outer H-shaped steel inside and outside the segment are locked with the two adjacent segments, and multiple pairs of inner H-shaped steel and outer H-shaped steel are arranged along the segment to lock the segments of the two adjacent piers to form a whole load-bearing structure, so as to ensure that the pier structure has sufficient bearing capacity and stability during the construction process before the joints of the segment are not constructed or do not reach sufficient strength.

10. The lightweight assembled partially prestressed concrete hollow column pier structure and its construction process according to claim 7, characterized in that: The UHPC wet joint casting formwork between the segments adopts a unitized assembled formwork, and the unitized assembled formwork is positioned and fastened by a temporary connection fixing structure; the inner mold of the unitized assembled formwork is provided with a grouting port.

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