CN113565010A

CN113565010A - Gate-type pier cross beam construction method and formwork

Info

Publication number: CN113565010A
Application number: CN202110711094.3A
Authority: CN
Inventors: 郑津蒲; 于兆阳; 田涌银; 翟建国; 张庆华; 宋振军; 刘新华; 张华�
Original assignee: China Railway 12th Bureau Group Co Ltd; Third Engineering Co Ltd of China Railway 12th Bureau Group Co Ltd
Current assignee: China Railway 12th Bureau Group Co Ltd; Third Engineering Co Ltd of China Railway 12th Bureau Group Co Ltd
Priority date: 2021-06-25
Filing date: 2021-06-25
Publication date: 2021-10-29

Abstract

The invention discloses a portal pier beam construction method and a formwork, wherein the portal pier beam construction method comprises the following steps: constructing a bearing platform; constructing a pier column; bottom die construction: welding the steel pipe column with a bearing platform embedded steel plate and a pier column embedded steel plate; welding an I-shaped steel beam on the steel pipe column; welding and laying a plurality of I-shaped steel longitudinal beams on the I-shaped steel cross beam; welding and laying a plurality of I-steel distribution beams on the I-steel longitudinal beam; installing upright posts on the I-shaped steel distribution beam, connecting the two upright posts by a cross bar to form a rectangular frame, and installing diagonal braces on diagonal lines of the rectangular frame; laying leveling I-beams on the vertical rods for leveling; laying a bottom die on the leveling I-shaped steel; loading and unloading according to the total load weight of 0 → 80% → 100% → 110% → 100% → 80% → 0, acquiring sedimentation data, and adjusting the bottom mold to a designed elevation; mounting the beam steel bars and the prestressed pipeline; constructing a side mold; pouring and forming; and (5) prestress engineering. The construction method realizes the simultaneous construction of the single-line beam and the gate pier and has high construction efficiency.

Description

Gate-type pier cross beam construction method and formwork

Technical Field

The invention belongs to the technical field of fastening equipment, and particularly relates to a portal pier beam construction method and a formwork.

Background

With the rapid establishment and development of traffic hubs in China, railways are used as traffic transport means, the construction cost and efficiency of the transportation means are very important to the effective operation of traffic, and the transportation means are links for communicating various regions in China.

At present, because the influence of external factors such as topography, the track generally all needs to be built on the overpass, in order to reduce to existing planning and produce the influence, if the transport means who has the platform constructs on the overpass, need dispose the platform beam structure of being convenient for mankind to get on or off the bus because of the platform, the horizontal span size increase of platform beam structure, can include at least one platform roof beam and single line roof beam, double line roof beam, in order to guarantee the platform roof beam, single line roof beam and double line roof beam well collocation, therefore, the template installation space of the double line roof beam that sets up between two single line roof beams is very narrow and small, it is the difficult problem that the skilled person in the art needs a lot of solution to build the template structure that satisfies the construction requirement (satisfies the load requirement and the space occupies for a short time) in narrow and small space how.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides the portal pier beam construction method and the formwork, which meet the construction requirements, can be repeatedly used, have low cost, meet the matching requirement of the space between the portal pier serving as the double-line beam and the single-line beam, ensure the compact construction of the viaduct and reduce the space occupancy rate of the viaduct.

The invention provides a method for constructing a portal pier beam, which comprises the following steps:

s1, construction of a bearing platform: placing bearing platform reinforcing steel bars pre-embedded with bearing platform pre-embedded steel plates into the foundation pit, installing a bearing platform template, and then pouring and forming at one time to form a bearing platform;

s2, pier column construction: accurately discharging the contour line and the center line of the pier column by using a total station, chiseling floating slurry on the top surface of the bearing platform in the range corresponding to the pier column, washing the floating slurry clean, repairing a connecting reinforcing steel bar, and pouring and forming at one time to form the pier column, wherein the two pier columns are oppositely arranged, each pier column is correspondingly provided with one bearing platform, and a pier column embedded steel plate is embedded in each pier column;

s3, bottom die construction: welding and connecting the steel pipe column with the bearing platform embedded steel plate and the pier column embedded steel plate; welding and mounting I-shaped steel cross beams at the tops of the steel pipe columns, wherein the I-shaped steel cross beams extend along the bridge length direction, the two I-shaped steel cross beams are oppositely arranged along the bridge width direction, and the I-shaped steel cross beams are arranged between the two pier columns; sequentially welding and laying a plurality of I-shaped steel longitudinal beams above the I-shaped steel cross beam along the bridge length direction, wherein the I-shaped steel longitudinal beams extend along the bridge width direction and are arranged between the two pier columns; sequentially welding and laying a plurality of I-shaped steel distribution beams above the I-shaped steel longitudinal beam along the bridge width direction, wherein the I-shaped steel distribution beams extend along the bridge length direction and are arranged between the two pier columns; installing upright posts above the I-steel distribution beam, connecting two upright posts which are adjacently arranged along the bridge width direction and the bridge length direction through cross bars to form a rectangular frame, and installing diagonal support rods on the diagonal of the rectangular frame to form a disc buckling frame; laying leveling I-shaped steel above the upright stanchion for leveling; laying a bottom die on the leveling I-shaped steel; sequentially loading and unloading according to the total weight of the load, namely 0 → 80% → 100% → 110% → 100% → 80% → 0, acquiring deformation values of the measuring points under various levels of loads to obtain settlement data, and adjusting the bottom die to the designed elevation according to the settlement data;

s4, mounting the beam steel bars and the prestressed pipeline: mounting and binding a bottom reinforcing mesh of the beam; installing a beam inner framework, bent steel bars and a prestressed pipeline; installing and binding vertical steel bars; installing a steel bar on the top surface of the cross beam;

s5, side mould construction: determining the edge line of the bottom plate of the cross beam according to measurement lofting, installing a side die according to the edge line, adhering sealing adhesive tapes at the joint of the side die and the bottom die, and coating release agents in the side die and the bottom die;

s6, casting and forming: taking a central line along the length direction of the bridge as a pouring starting point, symmetrically pouring in layers from the center to the two sides, wherein the pouring thickness of each layer is not more than 30 cm;

s7, prestress engineering: and constructing according to the sequence of pore canal molding → blanking and weaving → cable penetrating → tensioning → pore canal grouting.

Optionally, the side mold comprises a steel template, flat steel, channel steel, a back bar, a bolt, a tie rod, a nut and deformed steel; the channel steels are sequentially arranged on the outer side surface of one side, away from the cross beam, of the steel formwork at intervals; the back bars are arranged on one side, far away from the steel formwork, of the channel steel to form a plurality of sub-formworks, the flat steel is arranged at the contact position of two adjacent sub-formworks, and the bolts penetrate through the adjacent flat steel to achieve connection of the two sub-formworks; the end part of the pier stud, which is close to one side of the cross beam, is provided with a reserved hole, the deformed steel bar penetrates through the reserved hole and is oppositely arranged on the back bars of the two sub-templates of the pier stud and then is in threaded connection with the nut to form counter-pulling, and the nut is abutted against the back bars; the opposite pull rod penetrates through the back bars of the two sub-templates adjacently arranged on the pier column at the corners of the pier column and then is in threaded connection with the nut to form opposite pull, and the nut abuts against the back bars; the tie rod penetrates through the back bars of the two sub-templates oppositely arranged along the bridge length direction above the cross beam and then is in threaded connection with the nut to form the tie rod, and the nut is abutted to the back bars.

Optionally, two steel pipe columns which are adjacently arranged along the bridge length direction are provided with a scissor brace, the scissor brace comprises a first scissor brace and a second scissor brace which are arranged in a crossed manner, and two ends of the first scissor brace and two ends of the second scissor brace are connected through transverse pull rods respectively.

Optionally, the calculation formula of the total weight of the load is as follows: the total load is = (concrete dead weight load + template load + crowd machine load) × 110%.

Optionally, a plastic liner tube is inserted into the prestressed pipe, and the plastic liner tube is drawn out when the concrete is initially set.

The invention also provides a portal pier beam construction formwork, which comprises:

a bottom die, a side die and a bottom die support;

the bottom die support comprises a steel pipe column, an I-shaped steel cross beam, an I-shaped steel longitudinal beam, an I-shaped steel distribution beam, leveling I-shaped steel and a disc buckling frame; the plate buckling frame comprises upright rods, cross rods and inclined stay rods;

the bottom of the steel pipe column is welded with the bearing platform embedded steel plate, and the side wall of the steel pipe column is welded with the pier column embedded steel plate; the top of the steel pipe column supports the I-shaped steel beam, and the I-shaped steel beam extends along the bridge length direction; a plurality of I-shaped steel longitudinal beams are sequentially laid on the I-shaped steel cross beam along the bridge width direction, and the I-shaped steel longitudinal beams extend along the bridge width direction; a plurality of I-shaped steel distribution beams are sequentially laid on the I-shaped steel longitudinal beam along the bridge width direction, and the I-shaped steel distribution beams extend along the bridge length direction; the I-shaped steel distribution beam supports the upright rods, the cross rods connect the two adjacent upright rods along the bridge width direction and the bridge length direction to form a rectangular frame, and the diagonal of the rectangular frame is provided with the diagonal stay rods; the upright stanchion supports the leveling I-shaped steel for leveling; the bottom die is arranged on the leveling I-shaped steel; the side die is connected with the bottom die.

Optionally, the vertical rod comprises a bottom support, a top support and a vertical rod which can be connected with each other in a sleeved mode; the bottom support is supported on the I-shaped steel distribution beam; more than one vertical rod is sequentially sleeved on the bottom support; the top support is sleeved on the vertical rod; the leveling I-steel is supported on the jacking.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

1. in the invention, the bearing platform, the pier stud and the cross beam are sequentially formed by one-time pouring from bottom to top, so that the structural strength and the load capacity of the gate-type pier are ensured; preferably, the reinforcing steel bars at the lower part of the pier column and the reinforcing steel bars at the lower part of the pier column are integrally bound and formed, the reinforcing steel bars at the upper part of the pier column and the reinforcing steel bars at the lower part of the pier column are welded in a connecting mode to form the reinforcing steel bars of the pier column, and floating slurry in the range corresponding to the pier column on the top surface of the bearing platform is removed and washed before the pier column is poured, so that the structural strength of the connecting part of the bearing platform and the pier column is ensured; the whole die carrier is arranged between the two pier studs, the side dies are fixedly installed in a split mode between the side dies and the bottom die, and the side dies are oppositely pulled, and the die carrier basically does not occupy the space between the portal pier and the single-line beam, so that the single-line beam and the portal pier beam serving as the double-line beam can be constructed simultaneously, the construction period is greatly shortened, and the construction efficiency is high; more preferably, the supporting force of the whole die frame is provided by the pier column and the bottom die support, the bottom die support is mainly constructed by the I-steel, the coil buckling frame and the steel pipe column, the structural strength of the bottom die support is guaranteed by the advantages of the I-steel, such as excellent bending resistance, low cost, high precision, simplicity and convenience in installation, the advantages of the coil buckling frame, such as good safety, long service life and large space, all parts of the die frame can be recycled, and the use cost of the die frame is reduced; preferably, the mold frame is sequentially loaded and unloaded through different load total percentage, so that the influence of mold frame deformation and foundation settlement on the linear shape of the cast-in-place beam is effectively avoided, and the appearance integrity and the load-carrying performance of the beam are ensured; preferably, the construction method that the casting thickness of each layer is not more than 30cm is adopted according to the casting method that the center is firstly symmetrical and the two sides are symmetrically cast in layers in the cast-in-place process of the beam, so that the compactness (no bubbles, smooth surface and slurry) of each layer of casting layer is ensured, and the structural performance of the beam is ensured; more excellent, guaranteed the structural performance of crossbeam through prestressing force engineering, make it satisfy as the demand that the overpass supported.

2. According to the invention, all the sub-templates of the side mold are connected through bolts, the two sub-templates which are adjacently arranged or oppositely arranged are fixed through the opposite pull rods and the deformed steel bars, the side mold is supported through the bottom mold, the pier columns which are surrounded by the side mold and the deformed steel bars and penetrate through the pier columns, the structure is stable, and the occupied space is small. More preferably, the steel pipe column improves its structural strength through the bridging, and then improves the load carrying capacity of die carrier.

Drawings

Fig. 1 is a schematic flow chart diagram illustrating an embodiment of a method for constructing a beam of a gate pier according to the present invention;

FIG. 2 is a schematic structural view of one embodiment of the portal pier cross beam construction formwork of the present invention;

FIG. 3 is a schematic cross-sectional view of FIG. 2;

FIG. 4 is a schematic view of a portion of FIG. 3;

fig. 5 is a schematic structural view of another embodiment of the portal pier cross beam construction formwork of the invention;

fig. 6 is a schematic structural view of another embodiment of the portal pier beam construction formwork of the invention;

FIG. 7 is a left side view schematic of the structure of FIG. 6;

FIG. 8 is a schematic structural view of a side form of the present invention enclosing a pier stud;

fig. 9 is a schematic structural view of a side mold of the invention enclosed in a platform beam upright.

In all the figures, the same reference numerals denote the same features, in particular: 1-bearing platform, 11-bearing platform embedded steel plate, 12-reinforcing rib plate, 2-pier column, 21-pier column embedded steel plate, 22-preformed hole, 3-cross beam, 31-platform beam column, 32-track support base stone, 411-steel tube column, 412-cross brace, 413-first cross brace, 414-second cross brace, 415-transverse pull rod, 416-leveling steel plate, 42-I-steel cross beam, 43-I-steel longitudinal beam, 44-I-steel distribution beam, 451-vertical rod, 452-bottom support, 453-vertical rod, 454-top support, 455-cross rod, 456-diagonal rod, 46-leveling I-steel, 461-guard rail, 47-bottom mold, 48-side mold, 481-steel mold, 482-flat steel, 47-bottom mold, transverse, 483-channel steel, 484-back bar, 485-bolt, 486-counter pull rod, 487-nut and 488-thread steel.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In one embodiment of the present invention, as shown in fig. 1, a method for constructing a cross beam of a gate pier comprises the steps of:

s1, construction of a bearing platform: and (3) accommodating the bearing platform reinforcing steel bars pre-embedded with the bearing platform pre-embedded steel plates into the foundation pit, installing a bearing platform template, and then pouring and forming at one time to form the bearing platform.

Specifically, the i-steel members (i-steel cross beam 42, i-steel longitudinal beam 43, i-steel distribution beam 44 and leveling i-steel 46) include a vertical plate and two transverse plates arranged oppositely, and the two transverse plates are respectively arranged at two ends of the vertical plate along the height direction to play a main supporting role. The depth of the bearing platform 1 is 2-3m, the underground water level is below the base of the bearing platform, and when the geology of the bottom of the bearing platform 1 is silty clay and fine sand, the foundation pit needs to be protected by steel sheet piles. And after the foundation pit is excavated, the periphery of the foundation pit is timely protected by facing edges, meanwhile, personnel are organized for construction, and the exposure time of the foundation pit is shortened. The cushion cap reinforcing steel bars are processed and transported to the site for binding and forming in a processing factory, and meanwhile, pier stud reinforcing steel bars and cushion cap embedded steel plates 11 are embedded. The bearing platform template is a shaped steel template and is poured at one time. The concrete is intensively mixed and supplied by a mixing station, a concrete tank truck is adopted to transport the concrete to a construction site, and the chute flows into the bearing platform main body. The bearing platform 1 is constructed according to a conventional method.

S2, pier column construction: accurately discharging the contour line and the center line of the pier column by using a total station, chiseling floating slurry of the top surface of the bearing platform corresponding to the range of the pier column, cleaning the floating slurry, repairing and connecting reinforcing steel bars, pouring and forming at one time to form the pier column, wherein the two pier columns are oppositely arranged, each pier column is correspondingly provided with one bearing platform, and a pier column pre-embedded steel plate is pre-embedded in the pier column.

Specifically, before the pier stud 2 is constructed, a total station is used for accurately discharging the contour line and the center line of the pier stud, the floating slurry of the top surface of a bearing platform corresponding to the range of the pier stud 2 is chiseled and washed clean, the steel bar of the lower part of the pier stud is repaired because the steel bar of the lower part of the pier stud is pre-embedded in the bearing platform 1, and the steel bar of the upper part of the pier stud is connected to the steel bar of the lower part of the pier stud; and then building a pier stud operation platform, adopting 75 x 75mm angle steel for welding an operation platform framework at an interval of 1.2m, laying 14mm thread steel bars on the upper part of the operation platform as a walking platform, erecting a protective railing 461 on the operation platform, and hanging a double-layer dense mesh net on the protective railing 461 as an anti-throwing net. Preferably, before cast in place, more than one plastic pipe is embedded in the pier stud 2 close to the cross beam 3 in sequence along the bridge length direction, so that more than one reserved hole 22 is formed in the upper part of the pier stud 2.

The template of pier stud 2 adopts the design big block steel mould, and the design big block steel mould allocates the festival section according to the pier height, standard festival 2m, and adjustment festival 0.7m, 0.5m, adopts 25t crane monolithic to hoist and take one's place, and the concrete one-time casting is formed. After the construction is completed, the pier stud 2 is timely sprinkled with water for health preservation.

S3, bottom die construction: welding and connecting the steel pipe column with the bearing platform embedded steel plate and the pier column embedded steel plate; welding and mounting I-shaped steel cross beams at the tops of the steel pipe columns, wherein the I-shaped steel cross beams extend along the bridge length direction, the two I-shaped steel cross beams are oppositely arranged along the bridge width direction, and the I-shaped steel cross beams are arranged between the two pier columns; sequentially welding and laying a plurality of I-shaped steel longitudinal beams above the I-shaped steel cross beam along the bridge length direction, wherein the I-shaped steel longitudinal beams extend along the bridge width direction and are arranged between the two pier columns; sequentially welding and laying a plurality of I-shaped steel distribution beams above the I-shaped steel longitudinal beam along the bridge width direction, wherein the I-shaped steel distribution beams extend along the bridge length direction and are arranged between the two pier columns; installing upright posts above the I-steel distribution beam, connecting two upright posts which are adjacently arranged along the bridge width direction and the bridge length direction through cross bars to form a rectangular frame, and installing diagonal support rods on the diagonal of the rectangular frame to form a disc buckling frame; laying leveling I-shaped steel above the upright stanchion for leveling; laying a bottom die on the leveling I-shaped steel; sequentially loading and unloading according to the total load weight of 0 → 80% → 100% → 110% → 100% → 80% → 0, acquiring deformation values of the measuring points under various levels of loads to obtain settlement data, and adjusting the bottom mold to a designed elevation according to the settlement data.

In practical application, the steel pipe column 411 is preferably a phi 609mm steel pipe column with the wall thickness of 16 mm; the pier stud embedded steel plate 21 is preferably I-shaped steel I14 mm; the I-beam cross-beam 42 is preferably I32b double-split I-beam; the I-shaped steel longitudinal beam 43 is preferably a double-spliced 400 x 200mm section steel; the I-beam distribution beam 44 is preferably I14I-beam; the upright rod 451 is preferably a galvanized steel pipe with the diameter of 60mm and the wall thickness of 3.25 mm; the bottom die 47 is preferably a shaped steel die plate of a combination of 6mm steel plate and 10# channel steel. Specifically, step S3 includes the steps of:

s31, steel pipe column installation: and each bearing platform is provided with two steel pipe columns at intervals along the bridge length direction, and leveling steel plates are welded at the tops of the steel pipe columns so as to realize the flush arrangement of the leveling steel plates which are positioned on the four steel pipe columns and are farthest away from one side of the steel pipe columns.

Preferably, the reinforcing rib plates 12 are welded between the steel pipe columns 411 and the leveling steel plates 416, the reinforcing rib plates 12 are preferably welded and connected by 10 × 1cm triangular steel plates, and the number of the connected steel pipe columns 411 is not less than 8; the number of the leveling steel plates 416 arranged on different steel pipe columns 411 can be the same or different; the surface area of the leveling steel plate 416 is larger than the sectional area of the steel pipe column 411, so that the placement of the I-steel beam 42 is facilitated; the steel pipe column 411 is accurately hoisted in place, and is welded with steel pipe column limiting ribs and a cross brace 412 after being installed and positioned. Preferably, the scissors 412 comprise a first scissors strut 413 and a second scissors strut 414 which are arranged in a cross manner, and two ends of the first scissors strut 413 and the second scissors strut 414 are respectively connected through a transverse pull rod 415. Of course, in other embodiments of the present invention, more than two steel pipe columns 411 may be provided, and two steel pipe columns 411 adjacent to each other in the bridge length direction are provided with the cross braces 412. It should be noted that the steel pipe column 411 may be selectively provided with the cross brace 412 or without the cross brace 412.

S32, mounting an I-shaped steel beam: the method comprises the following steps of (1) double-splicing and welding two I-shaped steels I32b to form an I-shaped steel beam; marking (using chalk or ink lines and the like) the accurate installation position of the I-steel beam on the leveling steel plate, and after the I-steel beam is accurately hoisted in place, connecting the bottom of the I-steel beam with the leveling steel plate in a spot welding manner. It is worth explaining that spot welding not only strengthens the I-steel crossbeam in the structural strength of steel pipe column joint strength in order to increase the die carrier, can also avoid the I-steel crossbeam to appear the displacement phenomenon simultaneously, later stage spot welding accessible is got rid of the splice and is realized recycling respectively of I-steel crossbeam and steel pipe column.

S33, mounting the I-shaped steel longitudinal beam: welding two 400-200 mm section steels in a double splicing manner to form an I-shaped steel longitudinal beam; and hoisting and installing a plurality of groups of I-shaped steel longitudinal beams on the I-shaped steel cross beam with the middle line distance of 90cm, and connecting the bottom of the I-shaped steel longitudinal beam with the I-shaped steel cross beam in a spot welding manner after the I-shaped steel longitudinal beam is accurately in place. Similarly, spot welding not only strengthens the I-steel longitudinal beam in order to increase the structural strength of the die carrier in the connection strength of the I-steel transverse beam, but also can avoid the relative displacement phenomenon of the I-steel transverse beam and the I-steel longitudinal beam, and the later-stage spot welding can realize the respective recycling of the I-steel transverse beam and the I-steel longitudinal beam by removing the welding blocks.

S34, mounting the I-shaped steel distribution beam: and marking (using chalk or ink lines and the like) the mounting positions of the I-steel distribution beams on the I-steel longitudinal beams, and hoisting and arranging a plurality of I14I-steels at the corresponding mounting positions, wherein the central distance between the I-steel distribution beams positioned at the equal-height sections (middle sections) of the cross beams is 90cm, and the central distance between the I-steel distribution beams positioned at the chamfer sections (connecting sections close to one sides of the pier columns) of the cross beams is 60 cm.

S35, setting a disk buckle frame: the upright posts and the cross rods are sequentially arranged from bottom to top, the upright posts are sequentially arranged in the equal-height section at a center distance of 90cm along the bridge width direction and the bridge length direction respectively, and the upright posts are sequentially arranged in the chamfer section at a center distance of 60cm along the bridge width direction and the bridge length direction respectively; and after the vertical rods and the cross rods are installed, the diagonal brace rods are installed.

Preferably, the upright member 451 comprises a bottom support 452, a top support 454 and a vertical rod 453 which are connected with each other in a sleeved manner; the shoe 452 bears against the i-beam distribution beam 44; more than one vertical rod 453 is sequentially sleeved on the bottom support 452; the top support 454 is sleeved on the vertical rod 453; the leveling h-beam 46 is supported by the top bracket 454.

S36, installation of leveling I-shaped steel: and a jacking is arranged on the upright rod closest to one side of the cross beam, and a layer of 14# I-steel is laid above the jacking along the bridge width direction and leveled. Preferably, a running board is laid between the bottom die of the cross beam and the upper protective railing to serve as a construction operation platform.

S37, mounting a bottom die: and laying the bottom die above the leveling steel plate, arranging the 10# channel steel close to one side of the leveling steel plate, and arranging the 6mm steel plate close to one side of the cross beam.

S38, pre-pressing the bracket: loading a sand bag with the weight not less than 1.2 times of the total construction weight and the mass of about 1.4t above a bottom die, wherein the loading sequence is as follows: loading and unloading are carried out according to the total load weight of 0 → 80% → 100% → 110% → 100% → 80% → 0, and deformation values of the measurement points at the respective levels of loads are measured.

It should be noted that the unloading is performed according to a layered and progressive principle. Preferably, the measuring points are arranged at the L/2 and L/4 positions of each span (along the bridge width direction) and the pier stud, and each group is divided into a left point and a right point along the bridge length direction; and the observation mark is fixed at the side point so as to facilitate settlement observation. Specifically, before the load application and after the load application was 80%, 100%, and 110%, the observation was performed 1 time, every 3 hours thereafter, and the data at each measurement point was measured, and after the weight was applied for 24 hours, the data at each measurement point was measured again. And when the settlement amount is not more than 2mm in 24 hours, unloading can be carried out, the principle of gradual unloading and tracking measurement is followed, the unloading and the tracking measurement are carried out and recorded in detail, and the data obtained by prepressing are filed after unloading so as to be convenient for adjusting the standard height of the bottom die in formal construction. And (4) unloading after all loading is finished until the settlement of the observation point is stable, and respectively measuring the data of 100%, 80% and 0% of the load in the unloading process. And calculating the settlement and the inelastic deformation of each measuring point, and sorting and analyzing the observation data to obtain the support settlement data.

Preferably, the load balancing calculation is performed according to the equal load, and the total load weight value is (concrete dead weight load + template load + crowd equipment load) × 110%, wherein: and (3) the self-weight load of the concrete is provided according to the design drawing, part of the weight of the capping beam on each pier is borne by the pier top, and the rest weight is borne by the support. Concrete data borne by the bracket are as follows: the volume weight of prestressed reinforced concrete is 26.5kN/m3, the self weight of concrete is 145.75t, crowd machines, templates and wind load are taken, and the crowd machines, templates and wind load per meter are as follows: 6.28KN/m2, the crowd gear load is: 6.28KN/m2 × 9.1m ÷ 10t/kN ═ 5.7 t; the total load weight is (145.75 + 5.7) × 110%: 166.6 t. It is worth explaining that under different construction conditions and different sizes of parts, the concrete dead weight load, the formwork load and the crowd machine load can be changed correspondingly, and the actual construction is taken as the standard.

S4, mounting the beam steel bars and the prestressed pipeline: mounting and binding a bottom reinforcing mesh of the beam; installing a beam inner framework, bent steel bars and a prestressed pipeline; installing and binding vertical steel bars; and (5) installing the top surface steel bars of the cross beam.

Specifically, the welding of the cross beam steel bars adopts a layered welding method, namely, the welding is symmetrically and staggeredly carried out from the center of the framework to two ends, the lower part of the framework is welded firstly, and the upper part of the framework is welded secondly. The current amount of the electric welding machine is adjusted during the welding of the steel bars, so that the phenomenon of biting caused by overlarge current amount or improper operation is prevented. And after the steel bar is welded, removing all welding slag. After the steel bar is welded and the self-inspection is qualified, a supervision engineer is reported to check the steel bar, and then the next procedure construction can be carried out. In practical applications, when the installation position of the steel bar conflicts with the position of the prestressed pipe or anchor, the position of the steel bar should be properly adjusted to ensure that the position of the prestressed pipe or anchor meets the design requirements. When the steel bars are welded, the steel strands and the prestressed pipeline are prevented from being burnt by electric welding, and the situation that the tensioning fracture and the pipeline are blocked by concrete to cause the incapability of grouting the pore channel is avoided. Preferably, the bottom reinforcing mesh close to one side of the bottom die 47 is supported by concrete cushion blocks with the same marks as the cross beams 3, and the number of the concrete cushion blocks is not less than 4/m². The prestressed pipeline preferably adopts a galvanized metal corrugated pipe, the thickness of the steel strip is not less than 0.3mm, and the distance between the positioning steel bars of the rest parts is 50cm in a straight line section and 30cm in a curve section except that the positioning steel bars are arranged at each characteristic point of the prestressed pipeline. And a plastic pipe with the diameter slightly smaller than the inner diameter of the prestressed pipeline is preferably arranged in the prestressed pipeline and used as a plastic liner pipe, and the plastic liner pipe is drawn out when the concrete is initially set so as to ensure the success of subsequent strand pulling.

S5, side mould construction: and determining the edge line of the bottom plate of the cross beam according to measurement lofting, installing a side die according to the edge line, pasting a sealing adhesive tape at the joint of the side die and the bottom die, and coating a release agent in the side die and the bottom die.

Specifically, sideform 48 includes steel form 481, flat steel 482, channel 483, backing bar 484, bolt 485, tie rod 486, nut 487, and threaded steel 488; channel steel 483 is sequentially arranged on the outer side face of one side, away from the cross beam 3, of the steel template 481 at intervals; the back bars 484 are arranged on one side, far away from the steel templates 481, of the channel steel 483 to form a plurality of sub-templates, flat steels 482 are arranged at the contact positions of the two adjacent sub-templates, and bolts 485 penetrate through the adjacent flat steels 482 to achieve connection of the two sub-templates; a preformed hole 22 is formed in the end portion, close to the cross beam 3, of the pier stud 2, the deformed steel 488 penetrates through the preformed hole 22 and is oppositely arranged on the back bars 484 of the two sub-templates of the pier stud 2 and then is in threaded connection with the nuts 487 to form counter-pulling, and the nuts 487 abut against the back bars 484; the opposite pull rod 486 penetrates through the back bars 484 of two sub-templates which are adjacently arranged on the pier stud 2 at the corners of the pier stud 2 and then is in threaded connection with the nuts 487 to form opposite pull, and the nuts 487 abut against the back bars 484; the opposite pull rod 486 penetrates through the back bars 484 of the two sub-templates oppositely arranged along the bridge length direction above the cross beam 3 and then is in threaded connection with the nuts 487 to form opposite pull, and the nuts 487 abut against the back bars 484. It should be noted that, since the tie rod 486, the screw bar 488, and the bolt 485 are different members, the nut 487 fitted to the tie rod 487 may be a screw member corresponding to the tie rod, and all the nuts 487 are not necessarily identical in structure.

In practical application, as shown in fig. 2, as the portal pier which is located below the platform beam and serves as a double-line beam, except for pier stud 2 and beam 3, the upper side of beam 3 can also be provided with platform beam upright 31 for supporting the platform and track support cushion stone 32 for supporting the track support, in order to ensure the structural strength of beam 3 and platform beam upright 31 and track support cushion stone 32, the platform beam upright 31 steel bar corresponding to platform beam upright 31 and the track support cushion stone 32 steel bar corresponding to track support cushion stone 32 are integrally bound and formed with the beam steel bar and are integrally cast and formed at the same time. Preferably, in order to improve the structural strength of the formwork, the side formwork 48 is built from bottom to top at the bottom of the pier stud 2, as shown in fig. 6-8, the side formwork 48 covers the whole pier stud 2 and the cross beam 3 except for the bottom formwork 47, specifically, as shown in fig. 6 and 7, the sub formworks oppositely arranged along the bridge length direction are connected with each other in a reinforcing manner through the pull rod 486, and simultaneously, the bottom of the sub formworks oppositely arranged along the bridge length direction and the bridge width direction are connected with the bottom formwork 47 through the bolts 485 and the nuts 487; as shown in fig. 9, the sub-templates corresponding to the platform beam column 31 are connected to each other by tie rods 486 at four corners of the platform beam column 31, and the sub-templates corresponding to the platform beam column 31 are further connected to each other by bolts 485 and nuts 487. As shown in fig. 7 and 8, the sub-templates located on the upper portion of the pier stud 2 are not only connected in a counter-pulling manner by the deformed steel 488, but also the sub-templates corresponding to the whole pier stud 2 are connected in a counter-pulling manner by the counter-pulling rods 486 at the four corners of the pier stud 2. It should be noted that the platform beam columns 31 and the piers 2 may be sequentially provided with the tie rods 486 at intervals in the height direction.

S6, casting and forming: and taking a central line in the bridge length direction as a pouring starting point, symmetrically pouring in layers from the center to the two sides, wherein the pouring thickness of each layer is not more than 30 cm.

Specifically, the in-situ concrete pouring adopts layered pouring, the pouring is completed from the middle to two sides in sequence, the pouring thickness of each layer is not more than 30cm, in the pouring process, the concrete slump is checked at any time, the concrete is vibrated by adopting an inserted vibrating rod, the moving distance does not exceed 1.5 times of the action radius of the vibrating rod, and the action radius is about 8-9 times of the radius of the vibrating rod. The vibrating rod keeps 5-10cm with the side die 48 when vibrating, so as to avoid the vibrating rod from contacting a template or a prestressed pipeline and the like, when the upper layer concrete is vibrated, the vibrating rod is inserted into the lower layer concrete by about 10cm, each vibrating part is vibrated until the concrete stops sinking and no bubble is generated, the surface is flat and the concrete is spread, so as to avoid leakage vibration or over vibration, the vibrating rod is slowly pulled out after each vibrating part is vibrated, the compactness of the prestressed pipeline and the track support base stone 32 is particularly noticed when vibrating, and the vibrating rod is vibrated by a small rod with the diameter of phi 30. In the concrete pouring process, a specially-assigned person is arranged to track and inspect the conditions of the support and the template, and if the template has a slurry leakage phenomenon, the template is filled with sponge strips. Before concrete is poured, a vertical line is hung under a bottom die 47 at the position of an L/2 section and an L/4 section, and five observation points are arranged on each section, namely the left side, the left middle line, the right middle line and the right side. And (3) tying reinforcing rods under the vertical lines, burying the reinforcing rods at corresponding positions on the ground, marking lines at staggered positions of the two reinforcing rods so as to observe the settlement condition of the bottom plate in the concrete pouring process, immediately stopping pouring concrete if an abnormal condition occurs, and continuing construction after finding reasons. The concrete curing adopts geotextile covering and watering curing, the surface of the concrete is always in a wet state, and the curing time is not less than 14 days. And a concrete strength test block for controlling tensioning and dropping is placed on the beam 3, and the curing is carried out under the same condition. And in the curing period, the top surface of the beam is strictly forbidden to stack materials.

Specifically, in the pore channel forming process, when the prestressed pipeline is placed, according to the pipeline coordinate value, fixing steel bars are arranged at intervals of 0.50m according to the design requirement, the position of the pipeline is fixed, and the pipeline positioning error is smaller than 5 mm. Meanwhile, in order to avoid the blocking phenomenon when cement slurry enters the anchor backing plate during concrete pouring, the prestressed pipeline extends to the opening of the anchor backing plate, and the grouting hole of the anchor backing plate is tightly blocked by foam rubber. In order to ensure the smoothness of the prestressed pipeline, the plastic liner pipe can be pulled every half an hour according to the concrete pouring height in the concrete pouring process. When the anchor head is installed, the anchor head is required to be put into a groove and cannot be randomly placed. The limiting plate is characterized in that the steel strands and the holes are in one-to-one correspondence in the installation process, dislocation is prevented, the steel strands are broken in the tensioning process, the depth of the limiting plate groove is proper, over-shallow steel strand nicking is prevented from being severe, and clamping pieces are exposed to be longer or dislocated due to over-deep steel strand nicking.

In the blanking and bundling process, the steel strand is blanked according to the blanking length provided by design and considering the type of a field tensioning jack, a working anchor, an anchor backing plate, a tool anchor, a penetrating and tensioning mode and the like, and the blanking time is arranged after the concrete is poured. Cutting by a grinding wheel cutting machine, binding by thin iron wires within the range of 20cm at the cut, binding one iron wire at intervals of one meter after straightening and smoothing, preventing the steel bundles from loosening and winding, stacking the bound steel strand bundle number hanging plate, leaving the ground to keep dry, and covering to prevent rain.

In the bundle penetrating process, the cross beam steel strand preferably adopts a manual penetrating method, and the steel strand head is wound with an adhesive tape during bundle penetrating, so that the steel strand head is prevented from being hung.

In the tensioning process, the method can be specifically carried out by referring to the following steps:

checking the equipment: the force of the jack is generally measured and controlled by a hydraulic gauge, which is calibrated to accurately control the tension. Firstly, the oil pressure gauge is checked in a metering bureau, and the oil pressure gauge can be used in construction after the oil pressure gauge is tested to be qualified. And then selecting a large-tonnage weight loading universal testing machine to carry out a loading test, calibrating a system consisting of the jack and the oil pump, and using the calibrated system in construction after the calibration is qualified.

Arranging tensioning construction personnel:

the method comprises the following steps of forming a tensioning class, recording 2 persons for a technical responsible person 1, a technician 2 and a driver pump 2, carrying out technical training on the tensioning class before tensioning, and understanding knowledge in the aspects of equipment performance, operation rules, safety key and the like.

Stretching prestressed reinforcing steel

And tensioning the prestressed tendons according to technical specifications and design drawings. Before tensioning, impurities and accumulated water in the pipeline are removed, the beam concrete can be tensioned when the strength reaches 95% of a design value and the elastic modulus reaches 100% of the design value, and the beam can be tensioned after the age is not less than 7 days.

The tensioning is performed by adopting 2 jacks which are bilaterally symmetrical, two ends of each jack are synchronously tensioned, the tensioning sequence is performed according to the requirements in the drawing, the pre-stressing force adopts a double-control measure, the stress control is taken as the main part, the elongation control is taken as the auxiliary part, namely, the pre-stressing force value is taken as the main part of the reading of an oil pressure gauge, and the elongation value of the prestressed tendon is checked.

The tensioning procedure is 0 → 0.2 δ k (marking elongation) → a δ k (standing for 5 min) → bula B δ k (measuring elongation) → anchoring. During tensioning, measuring an elongation value while tensioning, adopting stress and strain dual control, controlling the error of the actual elongation value compared with the theoretical elongation value within +/-6%, suspending tensioning and informing a supervision engineer if the elongation value is abnormal, recording a tensioning field, timely finishing, reporting the supervision engineer, and processing according to the measures approved by the supervision engineer. It is worth to be noted that, in practical application, values of a and B are specifically set according to construction engineering, specifically, the tensile force = the tension control stress under the anchor/(1-duct module coefficient), and the duct module coefficient is confirmed by field test.

And uniformly commanding in the tensioning process. And (3) immediately stopping construction when an abnormal phenomenon or sound occurs, checking, performing tensioning after finding out reasons, finishing final tensioning, checking after 24 hours to confirm that no sliding wire or broken wire occurs, cutting redundant steel strands outside the anchor, sealing the anchor, cutting by using an angle grinder during cutting, and strictly prohibiting gas cutting or welding electrode cutting.

Calculating theoretical elongation value delta L of steel strand

△L=Pp*L/(Ap*Ep)

In the formula: pp-tensile force (N);

l is the length (mm) of the prestressed tendon;

ap-area of section of tendon (mm)²）；

Ep-modulus of elasticity (N/mm) of the tendon²）。

The actual elongation value delta L of the prestressed tendon tensioning is calculated according to the following formula:

△ L=△L1+△L2

Δ L1 — measured elongation from initial stress to maximum tensile stress;

DeltaL 2-the estimated elongation below initial stress, the elongation of adjacent stages can be used.

In the process of grouting the duct, the grouting method of the duct is required to meet the design requirements and is finished within 48 hours after the prestressed tendon is finally tensioned. Grouting in the same channel is continuously completed once. When grouting is interrupted due to the reason and continuous construction cannot be carried out, high-pressure water is used for flushing and then grouting is carried out again.

The tunnel grouting should also comply with the following regulations:

(1) when grouting, the temperature of the slurry is between 5 and 30 ℃. When the temperature is higher than 35 ℃, the grouting is carried out at night when the temperature is lower.

(2) Before grouting, high-strength cement slurry is used for sealing the holes of the anchorage device, and the thickness of the covering layer is not less than 15 mm.

(3) The pore canal grouting material is prestressed pipeline grouting material.

(4) When the cement paste is stirred, water is firstly added, then the prestressed pipeline grouting material is added, and the stirring is carried out by using a stirrer with the rotating speed not lower than 1000r/min, wherein the stirring is not less than 5 min. The mud pressing material is used along with stirring, the mud placed in the mud storage tank with the stirring function is continuously stirred, and the time interval from stirring to pressing into a pore canal is not more than 40 min. After the pressure slurry is evenly mixed, the pressure slurry can be pressed into the pore canal after being filtered by a screen with the pore size not more than 3mm x 3 mm.

(5) The pore canal grouting sequence should be carried out from bottom to top.

(6) The grouting material test piece should be sampled and made into 3 groups at the grouting place, 2 groups of standard curing are carried out for the compression strength test and the rupture strength test, and 1 group of standard curing is carried out along with the pier body under the same condition.

(7) After the cement slurry is finally set (about 21 hours), the grouting and slurry discharging valve can be detached.

(8) Grouting in the same pore canal is continuously carried out by using a piston type grouting pump and is completed at one time, and after grouting construction is finished, anchor sealing concrete construction is immediately carried out.

Preferably, step S7 is followed by the step of: s8, unloading: after the construction of the prestress engineering is finished, the frame can be dismounted as long as the grouting strength reaches the designed strength, the frame is dismounted uniformly according to the sequence of spanning the middle first and then removing the two sides, and the dismounting progress of the two ends is ensured to be consistent as much as possible.

In another embodiment of the present invention, as shown in fig. 2 to 9, a gate-type pier cross member construction formwork includes: a bottom die 47, a side die 48 and a bottom die support; the bottom die support comprises a steel pipe column 411, an I-steel cross beam 42, an I-steel longitudinal beam 43, an I-steel distribution beam 44, leveling I-steel 46 and a coil buckling frame; the plate buckle frame comprises an upright post 451, a cross bar 455 and a diagonal brace 456; the bottom of the steel pipe column 411 is welded with the bearing platform embedded steel plate 11, and the side wall of the steel pipe column 411 is welded with the pier column embedded steel plate 21; the top of the steel pipe column 411 supports an I-shaped steel beam 42, and the I-shaped steel beam 42 extends along the bridge length direction; a plurality of I-shaped steel longitudinal beams 43 are sequentially laid on the I-shaped steel cross beam 42 along the bridge width direction, and the I-shaped steel longitudinal beams 43 extend along the bridge width direction; a plurality of I-steel distribution beams 44 are sequentially laid on the I-steel longitudinal beam 43 along the bridge width direction, and the I-steel distribution beams 44 extend along the bridge length direction; the I-steel distribution beam 44 supports the upright rods 451, the cross rod 455 connects the two adjacently arranged upright rods 451 along the width direction and the length direction of the bridge to form a rectangular frame, and diagonal braces 456 are arranged on the diagonal lines of the rectangular frame; the upright 451 supports the leveling I-steel 46 for leveling; the bottom die 47 is arranged on the leveling I-shaped steel 46; the side die 48 is connected to the bottom die 47.

Optionally, sideform 48 comprises steel form 481, flat steel 482, channel 483, backing bar 484, bolt 485, tie rod 486, nut 487, and threaded steel 488; channel steel 483 is sequentially arranged on the outer side face of one side, away from the cross beam 3, of the steel template 481 at intervals; the back bars 484 are arranged on one side, far away from the steel templates 481, of the channel steel 483 to form a plurality of sub-templates, flat steels 482 are arranged at the contact positions of the two adjacent sub-templates, and bolts 485 penetrate through the adjacent flat steels 482 to achieve connection of the two sub-templates; a preformed hole 22 is formed in the end portion, close to the cross beam 3, of the pier stud 2, the deformed steel 488 penetrates through the preformed hole 22 and is oppositely arranged on the back bars 484 of the two sub-templates of the pier stud 2 and then is in threaded connection with the nuts 487 to form counter-pulling, and the nuts 487 abut against the back bars 484; the opposite pull rod 486 penetrates through the back bars 484 of two sub-templates which are adjacently arranged on the pier stud 2 at the corners of the pier stud 2 and then is in threaded connection with the nuts 487 to form opposite pull, and the nuts 487 abut against the back bars 484; the opposite pull rod 486 penetrates through the back bars 484 of the two sub-templates oppositely arranged along the bridge length direction above the cross beam 3 and then is in threaded connection with the nuts 487 to form opposite pull, and the nuts 487 abut against the back bars 484.

Preferably, before pouring the pier stud 2, a pier stud operation platform needs to be built, a welding operation platform framework with the interval of angle steel of 75 × 75mm being 1.2m is adopted, a threaded steel bar with the length of 14mm is laid at the upper part of the welding operation platform framework to serve as a walking platform, a protective barrier 461 is erected on the welding operation platform framework, and a double-layer dense mesh net is hung on the protective barrier 461 to serve as an anti-throwing net. Preferably, before cast in place, more than one plastic pipe is embedded in the pier stud 2 close to the cross beam 3 in sequence along the bridge length direction, so that more than one reserved hole 22 is formed in the upper part of the pier stud 2.

Optionally, the template of the pier stud 2 is a shaped large block steel mold, the template is adjusted into sections according to the pier height, the standard section is 2m, the adjusting sections are 0.7m and 0.5m, the template is hoisted in place by a single crane of 25t, and concrete is cast and formed at one time. After the construction is completed, the pier stud 2 is timely sprinkled with water for health preservation. Preferably, a runway plate is laid between the bottom mold 47 of the cross beam 3 and the upper protection railing 461 as a construction operation platform.

Optionally, two steel pipe columns 411 arranged adjacently along the bridge length direction are provided with a scissor support 412, the scissor support 412 comprises a first scissor support 413 and a second scissor support 414 which are arranged in a crossed manner, and two ends of the first scissor support 413 and two ends of the second scissor support 414 are respectively connected through a transverse pull rod 415.

Optionally, the upright member 451 comprises a bottom support 452, a top support 454 and an upright member 453, which are connected to each other in a sleeved manner; the shoe 452 bears against the i-beam distribution beam 44; more than one vertical rod 453 is sequentially sleeved on the bottom support 452; the top support 454 is sleeved on the vertical rod 453; the leveling h-beam 46 is supported by the top bracket 454.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method for constructing a portal pier beam is characterized by comprising the following steps:

2. The method of constructing a cross member of a gate pier as claimed in claim 1, wherein:

the side mold comprises a steel template, flat steel, channel steel, a back bar, bolts, opposite pull rods, nuts and deformed steel bars;

the channel steels are sequentially arranged on the outer side surface of one side, away from the cross beam, of the steel formwork at intervals; the back bars are arranged on one side, far away from the steel formwork, of the channel steel to form a plurality of sub-formworks, the flat steel is arranged at the contact position of two adjacent sub-formworks, and the bolts penetrate through the adjacent flat steel to achieve connection of the two sub-formworks;

the end part of the pier stud, which is close to one side of the cross beam, is provided with a reserved hole, the deformed steel bar penetrates through the reserved hole and is oppositely arranged on the back bars of the two sub-templates of the pier stud and then is in threaded connection with the nut to form counter-pulling, and the nut is abutted against the back bars; the opposite pull rod penetrates through the back bars of the two sub-templates adjacently arranged on the pier column at the corners of the pier column and then is in threaded connection with the nut to form opposite pull, and the nut abuts against the back bars;

the tie rod penetrates through the back bars of the two sub-templates oppositely arranged along the bridge length direction above the cross beam and then is in threaded connection with the nut to form the tie rod, and the nut is abutted to the back bars.

3. The method of constructing a cross member of a gate pier as claimed in claim 1, wherein: the steel pipe columns which are adjacently arranged along the bridge length direction are provided with bridging struts, each bridging strut comprises a first bridging strut and a second bridging strut which are arranged in a crossed mode, and the two ends of each first bridging strut are connected through transverse pull rods.

4. The method of constructing a cross member of a gate pier as claimed in claim 1, wherein: the calculation formula of the total weight of the load is as follows: the total load is = (concrete dead weight load + template load + crowd machine load) × 110%.

5. The method of constructing a cross member of a gate pier as claimed in any one of claims 1 to 4, wherein: and a plastic liner tube is inserted into the prestressed pipeline, and the plastic liner tube is drawn out when the concrete is initially set.

6. The utility model provides a gate-type mound crossbeam construction die carrier which characterized in that includes:

a bottom die, a side die and a bottom die support;

7. The gate-type pier beam construction formwork of claim 6, wherein:

8. The gate-type pier beam construction formwork of claim 6, wherein: the steel pipe columns which are adjacently arranged along the bridge length direction are provided with bridging struts, each bridging strut comprises a first bridging strut and a second bridging strut which are arranged in a crossed mode, and the two ends of each first bridging strut are connected through transverse pull rods.

9. The gate-type pier beam construction formwork of claim 6, wherein: and a plastic liner tube is inserted into the prestressed pipeline, and the plastic liner tube is drawn out when the concrete is initially set.

10. The gate-type pier beam construction formwork of any one of claims 6 to 9, wherein:

the upright rod comprises a bottom support, a top support and a vertical rod which can be mutually sleeved and connected;

the bottom support is supported on the I-shaped steel distribution beam; more than one vertical rod is sequentially sleeved on the bottom support; the top support is sleeved on the vertical rod; the leveling I-steel is supported on the jacking.