CN106284103A - Steel reinforced concrete combination beam roof steel bar concrete high-altitude cantilever pouring construction method - Google Patents

Abstract

The invention discloses a kind of steel reinforced concrete combination beam roof steel bar concrete high-altitude cantilever pouring construction method, including a) first carrying out wing plate tripod and the installation of wing plate template；B (), by using wing plate template as work platforms, carries out chamber inner support system and the installation of chamber template；Carry out after (c) between case, supporting the installation of template between system and case；D () girder steel roof steel bar is installed；The roof steel bar concreting of (e) girder steel；The top board pre-stress system stretch-draw of (f) girder steel；G () stretch-draw completes post jacking sealing off and covering anchorage and carries out the pier consolidation construction of girder steel；H () girder steel roof plate template is removed.The present invention overcomes conventional top plate concrete template in construction process height to be difficult to regulation, and the problem such as insufficient light during form removable in chamber, there is provided a kind of and possess the height facilitating adjusting template, and light required when being provided that form removable in chamber and improve the construction method of the advantages such as work efficiency.

Description

Construction method of high-altitude cantilever pouring of steel-concrete composite beam roof reinforced concrete

technical field

The invention relates to the technical field of building construction, in particular to a high-altitude cantilever pouring construction method for steel-concrete composite beam roof reinforced concrete.

Background technique

With the rapid development of urban construction, more and more complex environments put forward higher requirements for urban bridge construction. At present, steel-concrete composite beams are more and more widely used because of their strong spanning ability, economy and high efficiency. However, there are still many problems in the construction of the formwork and formwork brackets used in the construction of reinforced concrete on the roof. For example, the height of the formwork is not easy to adjust. Usually, when the formwork needs to be readjusted after installation, it will take a lot of work and time-consuming. , laborious, and a waste of resources. Secondly, the formwork support consumables in the roof reinforced concrete construction are relatively large, and a large amount of material is usually cut to build a relatively safe and stable support. The third is the installation and removal of the formwork support, especially the formwork in the box room. Dismantling, because the light in the box room is insufficient, it is inconvenient to disassemble the formwork bracket in the box room.

Contents of the invention

The purpose of the present invention is to overcome the problems such as difficulty in adjusting the formwork height in the roof concrete construction process and the lack of light when the formwork in the box room is removed, and to provide a formwork with convenient height adjustment, and can provide the necessary space for the formwork removal in the box room. A high-altitude cantilever pouring construction method for steel-concrete composite beam roof reinforced concrete with light and improved work efficiency.

The present invention is realized through the following technical scheme: a construction method for high-altitude cantilever pouring of reinforced concrete on the roof of a steel-concrete composite beam, comprising the following steps:

(a) First install the wing tripod and the wing template;

(b) By using the wing formwork as the working platform, the installation of the support system and the formwork of the box room is carried out;

(c) Afterwards, install the support system between the boxes and the formwork between the boxes;

(d) Steel beam roof reinforcement installation;

(e) pouring of reinforced concrete on the steel beam roof;

(f) Tensioning of steel girder roof prestressing system;

(g) After the tensioning is completed, grout the anchor and carry out the pier beam consolidation construction of the steel beam;

(h) Steel girder roof formwork removal.

Before the steps of the above method, the construction plan is prepared first, wherein the load test is carried out on the wing plate tripod and the wing plate formwork, the support system in the box room and the box room formwork, the support system between the boxes and the formwork between the boxes, and the structural calculation results and the safety of the structure are verified. It can grasp the limit and bearing capacity of each formwork and support system in real time, and prevent and control the safety of the formwork more comprehensively. After preparing the construction plan, install the wing plate tripod first, and place the adjustable wing plate tripod on the At the reinforced wing plate and the steel beam web, after fixing the wing plate tripod, place the horizontal and vertical square wood on the wing plate tripod. The square wood is conducive to the uniform load distribution and reduces the deformation of the wing plate formwork. The wing plate tripod and the After the installation of the wing plate formwork is completed, the installation of the support system and the box room formwork in the installation box is carried out by using the wing plate formwork as a working platform. The installation of the support system formwork in the box room first places the support bar in the box room, and places it on the top of the support bar. Supporting beams, the supporting beams are placed at the steel beam flanges, on the supporting beams, the square wood that is beneficial to the uniform load distribution is secured, and the box room formwork with ventilation holes is installed on the square wood, and the box room formwork with ventilation holes is installed. The box room formwork can satisfactorily solve the reason of insufficient light when the box room formwork is removed and at the same time facilitate the transfer of materials. After the box room formwork is installed, install the inter-box support system and the inter-box formwork. The inter-box support system is equipped with T-shaped steel bars and For the tie rods, T-shaped steel bars are fully welded on the steel beam flange, double-row steel pipes are arranged on the T-shaped steel bars, and the double-row steel pipes and T-shaped steel bars are fixed through the fixed cover. The tie rods pass through the fixed cover and double-row steel pipes in sequence, and the formwork between the boxes is hoisted to the steel beam flange at the bottom of the tie rods and fixed by shear nails. The support system and formwork between the boxes have a simple structure and are easy to install and disassemble. All formwork installations are completed. Finally, clean the formwork, mark the top surface of the roof reinforced concrete on the side of the wing plate formwork, make the height of the wing plate formwork meet the construction requirements through the adjustable wing plate tripod, and reduce unnecessary work caused by the inability to adjust the formwork height After the height of the formwork support system is adjusted, the roof reinforcement is installed. After the roof reinforcement is completed, the internal bundle installation in the prestressing system is carried out. The internal bundle pipeline adopts plastic bellows. After the pipeline installation is completed, prestress Pay attention to protect the bellows during installation and welding, and repair any damage in time to avoid later rework. After the installation of the inner beam is completed, pour the concrete on the steel beam roof. The steel beam roof is poured with C50 non-shrinkage concrete. When the concrete reaches 100% After the strength is designed, the external cables are installed. After the external cables are installed, the prestressing system of the steel girder roof is stretched. The pier-beam consolidation construction of the beam. After the whole construction is completed, 1*1m manholes are set on the top plate of the tension port during the prestressing arrangement. The manholes are set every about 12m along the bridge direction, and finally the formwork is removed. First remove the wing tripod and the wing formwork, then remove the support system and formwork in the box room, and finally remove the support system and formwork between the boxes. The above construction method can effectively shorten the construction time and improve the construction efficiency. economic effect, the whole The operation is safe and reliable.

Further, the wing plate tripod in the step (1) is mainly composed of a main vertical bar, a horizontal bar and a lower chord, the horizontal bar is perpendicular to the main vertical bar, the lower chord is connected with the main vertical bar and the horizontal bar respectively, and the main vertical bar and the lower chord are respectively connected. The top of the vertical pole is connected to the steel beam flange through high-strength bolts, the lower chord is connected to the steel beam web through a jacking bracket, and at least one adjustable jacking bracket is provided on the crossbar, and a hanging bracket is welded under the crossbar. There is also a guardrail at the free end of the crossbar, a safety net is arranged on the wing tripod, and the two ends of the safety net are respectively suspended on the lower chord and the guardrail, and a crossbar is also arranged above the wing tripod. Vertical square wood.

Further, the installation steps of the wing plate tripod and the wing plate formwork in the step (a) are as follows:

(a.0) Hoist the wing tripod to the designated position with a crane;

(a.1) Connect the lower chord of the wing tripod to the web of the steel beam through jacking;

(a.2) Tighten the bottom support at the joint with a fixing piece;

(a.3) Use reinforcing pieces to strengthen and fix this fixing piece;

(a.4) The top of the main pole of the wing plate tripod is fixedly connected with the steel beam wing plate through high-strength bolts;

(a.5) After the final screwing of high-strength bolts, seal the nuts with glass glue;

(a.6) After installing the wing tripod, install the horizontal and vertical square timber on the wing tripod;

(a.7) After installing the horizontal and vertical timbers, adjust the jacking on the upper part of the wing tripod according to the design elevation;

(a.8) Fix the wing plate formwork on the square timber;

(a.9) Weld the basket to the crossbar of the wing tripod;

(a.10) Finally hang the wing panel safety net on the bottom chord and guardrail.

Further, the supporting system in the chamber in the step (b) is mainly composed of a supporting beam and at least two supporting rods, at least one square log is arranged on the upper side of the supporting beam, and the lower part is connected to the supporting rod through an adjustable jacking bracket. Horizontal reinforcing rods are also arranged between the supporting rods, and the bottom of the supporting rods is connected with the support pad in the chamber.

Further, the installation steps of the support system and the formwork in the chamber in the step (b) are as follows:

(b.0) Use the wing template as the working platform to place the support rods in the chamber;

(b.1) Fixedly connect the support rod with the support pad at the bottom of the chamber;

(b.2) Then install horizontal stiffeners on the support poles;

(b.3) Place the supporting beam on the steel beam flange through the adjustable jack;

(b.4) Afterwards install square timbers on the supporting beams;

(b.5) Finally, place the box formwork with ventilation holes on the square timber.

Further, in the step (c), the support system between the boxes is mainly composed of T-shaped steel bars and tie rods. The bottom of the T-shaped steel bars is fully welded on the steel beam flange, and the top is connected by a fixed cover to the double-row steel pipes and T-shaped steel bars. Fixed, the support system between the boxes is also provided with a pair of tie rods, the pair of tie rods pass through the fixed cover and the double row of steel pipes in turn, and the bottom of the pair of tie rods is used to fix the formwork between the boxes to the steel beam wing plate through shear nails.

Further, the step (c) installation steps of the inter-box support system and the inter-box formwork:

(c.1) First, fully weld the T-shaped steel bar on the steel beam flange;

(c.2) Second, install double rows of steel pipes on top of the T-bars;

(c.3) Install the fixed cover again to fix the double-row steel pipe on the top of the T-shaped steel bar;

(c.4) Pass the pair of tie rods through the fixed cover and the double-row steel pipes in turn;

(c.5) Finally, hang the inter-box formwork to the steel beam flange at the bottom of the tie rod and fix it with shear nails.

Further, the tensioning of the prestressing system in the step (f) includes the tensioning of the internal bundle and the external cable, and the tensioning steps of the prestressing system are as follows:

(f.0) Stretch the outer cable first;

(f.1) Re-tensioning the inner bundle;

(f.2) Check the elongation of tension;

(f.3) Grouting and anchoring after tensioning is completed.

Further, in the step (e), the steel girder roof is poured using C50 non-shrinkage concrete.

Compared with the prior art, the present invention has advantages and beneficial effects as follows:

(1) The above-mentioned construction method is beneficial to the situation where the foundation of the construction site is weak or the structure is too high, and there are traffic under the bridge, high-altitude overhangs that are inconvenient to erect supports, etc. Efficiency, good social and economic benefits;

(2) By setting an adjustable jacking bracket on the wing plate tripod, the height of the wing plate formwork can be adjusted, which effectively solves the problem that the formwork is difficult to adjust. This structure is simple and functional;

(3) By setting vent holes in the formwork of the box room, it can solve the problem of hindering the disassembly due to insufficient light when the support system is removed in the box room, which is beneficial for the operator to easily remove the formwork;

(4) The formwork between the boxes is constructed by hanging the formwork, and the structure of the supporting system between the boxes is simple, which greatly reduces the difficulty of the construction of the formwork between the boxes.

Description of drawings

Fig. 1 is a construction process flow chart of the present invention;

Fig. 2 is the structural representation of wing plate tripod and wing plate formwork of the present invention;

Fig. 3 is a structural schematic diagram of the supporting system and the template of the chamber in the chamber of the present invention;

Fig. 4 is a schematic diagram of a support system between boxes and a formwork between boxes of the present invention;

Fig. 5 is a side view of the supporting system between boxes of the present invention;

Among them: 1—main pole, 2—bottom chord, 3—horizontal bar, 4—jacking, 5—square timber, 6—safety net, 7—hanging basket, 8—support rod, 9—support beam, 10— Support pad, 11—horizontal reinforcing rod, 12—air vent, 13—double row steel pipe, 14—pair of tie rods, 15—fixed cover, 16—T-shaped steel bar.

detailed description

The present invention will be further described in detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto, without departing from the above-mentioned technical thought of the present invention, various replacements and changes can be made according to common technical knowledge and conventional means in the art , should be included within the scope of the present invention.

Example:

This embodiment discloses a high-altitude cantilever pouring construction method for reinforced concrete on the roof of a steel-concrete composite beam. It mainly aims to overcome the problems that the height of the formwork is difficult to adjust during the construction of the roof concrete in the past, and the light is insufficient when the formwork is removed in the box chamber. It is convenient to adjust the height of the formwork, and can provide the light required for the removal of the formwork in the box and improve work efficiency. The entire construction process is shown in Figure 1.

The first is the installation of the wing plate tripod and the wing plate formwork. The wing plate tripod is shown in Figure 2. It is designed according to the construction load and made of Q235 steel pipe steel. The main pole 1 and the lower chord 2 are under greater force Φ70×4.5mm steel pipe is used, and the remaining steel pipes are made of Φ48×3.5mm steel pipe assembly welding. The end of main pole 1 is reinforced with 10mm thick steel plate due to the complicated force. The top of the main pole 1 of the wing plate tripod is fixedly connected with the steel beam wing plate by high-strength bolts and tightened. The tightening is divided into initial screwing and final screwing. The jacking 4 is connected to the web of the steel beam, and the bottom jacking 4 is tightened with a wooden wedge at the joint, so that the wooden wedge fits the web of the steel beam more closely, and finally it is reinforced with reinforcement nails Fixed, the crossbar 3 is perpendicular to the main pole 1, and the free end of the crossbar 3 is also provided with a guardrail. The wing-plate tripod is set every 1m along the length of the bridge, and finally the wing-plate tripod is connected with a steel pipe. Three horizontal and vertical rows of square timbers 5 are installed on the wing plate triangular plate. The square timbers 5 can be used to distribute the load evenly. On one side of the wing plate formwork, the edge line of the bridge is accurately released and the elevation is marked. The upper part of the wing plate tripod can be adjusted. 4. Adjust the wing plate tripod to place the formwork at the corresponding elevation. A hanging basket 7 is welded on the cross bar 3 of the wing plate tripod. The hanging basket 7 is covered with square timber 5 as an unloading platform, Two layers of safety nets 6 are also suspended at the bottom, and the safety nets 6 are connected with the lower chord 2 and the guard plate respectively.

After the wing plate support system and the wing plate formwork are installed, the wing plate formwork is used as the working platform to carry out the installation of the support system in the chamber and the formwork between the chambers, as shown in Figure 3. The operator places the support rod 8 in the chamber, and the support rod 8 and the The support pad 10 at the bottom of the box chamber is vertically fixed, and then a horizontal reinforcement bar 11 is installed on the support bar 8, and the support beam 9 is also installed on the top of the support bar 8, and the square wood 5 is placed above the support beam 9, and the square wood 5 is conducive to uniform load distribution. Install the inter-box formwork with vent 12 at last, the shape of the inter-box formwork is a chamfered shape, and the chamfered formwork needs to be strictly pulled to control the thickness of the roof reinforced concrete.

After the support system and formwork in the box room are installed, the support system and formwork between the boxes are installed, as shown in Figure 4 and Figure 5, and the T-shaped steel bar 16 is fully welded on the steel beam wing, keeping it vertical, and welding After the T-shaped steel bars 16 are installed, double-row steel pipes 13 are installed on the top of the T-shaped steel bars 16, and the double-row steel pipes 13 and the T-shaped steel bars 16 are fixed by the fixed cover 15. Go through the fixed cover 15 and the double-row steel pipes 13 in turn, lift the hanging formwork between the boxes to the steel beam flange at the bottom of the tie rod 14, fix the formwork between the boxes with shear nails, and set the supporting system between the boxes at every 70cm distance along the bridge. And the formwork between the boxes, combined with the steel beam roof reinforcement, the support system between the boxes and the formwork between the boxes are integrated horizontally and vertically to enhance stability and avoid instability under load.

After completing the installation of the above formwork, clean the formwork. After cleaning, first mark the concrete top surface on one side of the formwork, and then install the roof reinforcement. When installing the roof reinforcement, pay attention to controlling the thickness of the reinforcement protective layer. After the installation of the reinforcement, prestress For the installation of the body harness in the system, first install the body harness pipe. The body harness pipe is made of plastic corrugated pipe. The plastic corrugated pipe has good sealing performance, no air leakage, and no water leakage. The joint can be welded with a sealed joint or a special plastic welding machine, and the material loss Small size, low cost and other advantages, after the installation of the plastic corrugated pipe is completed, it will be threaded.

After the installation of the steel beam roof reinforcement and internal beams is completed, the roof reinforcement concrete is poured. The roof reinforcement is poured with C50 non-shrinkage concrete. The roof concrete is poured from both sides to the middle with two pump trucks at one time. After the pouring is completed, Concrete is vibrated and vibrated by fixed personnel and posts to prevent leakage and over-tamping. Before the initial setting of the concrete, the work is manually finished and roughened. After the initial setting of the concrete, the beams and slabs are exposed to water and covered with work cloth.

Finally, after the concrete reaches 100% design strength, the external cables in the prestressing system are installed. After the external cables are installed, the roof prestressing system is stretched. The external cables are first stretched, and then the internal bundles are stretched. Both ends of the tensioning are used, and the tensioning control force is used to control the tensioning, and the elongation is checked. After the prestressed tensioning is completed, the grouting is used to seal the anchor and the pier beam consolidation construction of the steel beam is carried out.

After the entire construction is completed, the construction formwork is finally removed. First, the wing plate formwork is removed from the square wood 5, and then the operator stands on the hanging basket 7 of the dismantling platform and unscrews the high-strength bolts from one side to the other. Loosen the nails and take out the wooden wedges, then hang them down with a crane, remove the formwork in the box room, take out the support system from the manhole after unloading, loosen the shear nails in the formwork between the boxes, and then use steel wires to The formwork is hung down, and after the formwork is removed and cleaned up, the manhole is sealed.

One is to use the method disclosed in the present invention to deal with the construction site’s weak foundation or high structure, and under the bridge open to traffic, it is inconvenient to set up the high-altitude cantilever of the bracket and other construction inconveniences. Have good social and economic benefits;

The second is to simplify the formwork support system, reduce the work intensity, have high construction efficiency, and avoid unnecessary waste of materials;

The third is that the construction method disclosed by the invention has achieved good social benefits, shortened the construction period, and has significant economic benefits.

As far as the actual engineering is concerned, the entire project is a continuous viaduct, and the bridge is designed according to the left and right two independent bridges. The left mileage is Z11+724.607~Z11+810.815, a total of 85.2m, and the right mileage is Y11+728.182~Y12+ 007.718 has a total of 3 joints of 279.7m in steel-concrete composite beam structure with a maximum span of 71m. The single-width bridge is composed of three steel-concrete combined beams, the roof is a reinforced concrete structure, and the wing cantilever reaches 2.1m. The project adopts this construction method and has completed the Z9 joint roof pouring. The construction is fast, the concrete is smooth and dense, the lines are smooth, and the appearance color is consistent, which has won unanimous praise from the owners. Practice has proved that adopting the construction method of the present invention has the characteristics of safety, high quality and high efficiency.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications and equivalent changes made to the above embodiments according to the technical essence of the present invention all fall within the scope of the present invention. within the scope of protection.

Claims (9)

1. steel-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction method, it is characterised in that: comprise the following steps:

A () first carries out wing plate tripod and the installation of wing plate template；

B (), by using wing plate template as work platforms, carries out chamber inner support system and the installation of chamber template；

Carry out after (c) between case, supporting the installation of template between system and case；

D () girder steel roof steel bar is installed；

The roof steel bar concreting of (e) girder steel；

The top board pre-stress system stretch-draw of (f) girder steel；

G () stretch-draw completes post jacking sealing off and covering anchorage and carries out the pier consolidation construction of girder steel；

H () girder steel roof plate template is removed.

Steel the most according to claim 1-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction method, its feature exists In: in described step (a), wing plate tripod is mainly made up of main vertical rod (1), cross bar (3), lower boom (2), and described cross bar (3) hangs down Straight in main vertical rod (1), lower boom (2) is connected with main vertical rod (1) and cross bar (3) respectively, and high-strength bolt is passed through on main vertical rod (1) top Being connected with girder steel wing plate, described lower boom (2) is connected with steel beam web plate by jacking (4), and described cross bar is additionally provided with at least on (3) One jacking that can regulate (4), cross bar (3) lower section is also welded with hanging basket (7), and cross bar (3) free end is additionally provided with guardrail, described Being provided with safety net (6) on wing plate tripod, the two ends of described safety net (6) are suspended on lower boom (2) and guardrail respectively, institute State wing plate tripod and be arranged above the transverse and longitudinal lumps of wood (5).

Steel the most according to claim 2-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction method, its feature exists In: in described step (a), the installation steps of wing plate tripod and wing plate template are as follows:

(a.0) winch to specify position by wing plate tripod with crane；

(a.1) by jacking (4), lower boom (2) and the steel beam web plate of wing plate tripod are connected；

(a.2) at junction fixture by urgent for bottom jacking (4)；

(a.3) this fixture is strengthened fixing with girth member again；

(a.4) main vertical rod (1) top of wing plate tripod is connected by high-strength bolt and girder steel wing plate are fixing；

(a.5) with glass cement, nut is closed after high-strength bolt is twisted eventually；

(a.6), after installing wing plate tripod, wing plate tripod is installed the transverse and longitudinal lumps of wood (5)；

(a.7) after installing the transverse and longitudinal lumps of wood (5), according to the jacking (4) on designed elevation regulation wing plate tripod top；

(a.8) wing plate template is fixedly placed on the lumps of wood (5)；

(a.9) hanging basket (7) is welded on the cross bar (3) of wing plate tripod；

(a.10) finally wing plate safety net (6) is suspended on lower boom (2) and guardrail.

Steel the most according to claim 1-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction method, its feature exists In: described step (b) raising middle flask indoor support owner to be made up of support beam (9) and at least two support bars (8), described support beam (9) being provided above at least one lumps of wood (5), lower section is connected with support bar (8) by the jacking (4) that can overregulate, described Being additionally provided with horizontal bracing piece (11) between strut (8), support bar (8) bottom is connected with the pad (10) in chamber.

Steel the most according to claim 4-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction method, its feature exists In: the installation steps of described step (b) chamber inner support system and chamber template are as follows:

(b.0) support bar (8) is placed in chamber using wing plate template as work platforms；

(b.1) it is connected fixing with the pad (10) of chamber inner bottom part for support bar (8)；

(b.2) then at support bar (8) the horizontal bracing piece of upper installation (11)；

(b.3) support beam (9) is laid at girder steel wing plate by the jacking (4) by regulating；

(b.4) after, the lumps of wood (5) is installed in support beam (9)；

(b.5) finally the chamber template with passage (12) is placed on the lumps of wood (5).

Steel the most according to claim 1-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction method, its feature exists In: supporting owner between described step (c) raising middle flask to be constituted by T-steel muscle (16) with to pull bar (14), described T-steel muscle (16) end Portion's full weld is on girder steel wing plate, and double-row steel pipe (13) and T-steel muscle (16) are fixed, between described case by top by fixing lid (15) Supporting system and be additionally provided with pull bar (14), described sequentially pass through pull bar (14) fixes lid (15) and double-row steel pipe (13), to drawing Template between case is fixed at girder steel wing plate by bar (14) bottom by WELDING STUDS.

Steel the most according to claim 6-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction method, its feature exists In；Support between described step (c) case and be and the installation steps of template between case:

(c.1) first by T-steel muscle (16) full weld on girder steel wing plate；

(c.2) double-row steel pipe (13) is secondly installed on T-steel muscle (16) top；

(c.3) fixing lid (15) is installed again and double-row steel pipe (13) is fixed on T-steel muscle (16) top；

(c.4) pull bar (14) will be sequentially passed through fixing lid (15) and double-row steel pipe (13) from secondary；

(c.5) finally winch to fix at girder steel wing plate and with WELDING STUDS by template between case to pull bar (14) bottom.

Steel the most according to claim 1-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction method, its feature exists In: pre-stress system stretch-draw described in described step (f) includes the stretch-draw of internal bundle and external tendon, pre-stress system stretch-draw step As follows:

F.0) pretensioning external tendon；

(f.1) stretch-draw body is interior again restraints；

(f.2) elongation of stretch-draw is checked；

(f.3) stretch-draw completes post jacking sealing off and covering anchorage.

9. according to the steel described in any one in claim 1-8-mixed combination beam roof steel bar concrete high-altitude cantilever pouring construction party Method, it is characterised in that: in described step (e), girder steel top board pours employing C50 non-shrinkage concrete.