Construction method of large-dip-angle bridge tower without lower beam

Abstract

The application discloses a construction method of a large-inclination no-under-cross-beam bridge tower, which comprises the following steps: S1, tower column construction; S2, middle tower column construction; S3, upper tower column construction; and S4, upper cross-beam construction. The upper cross-beam of the main tower is constructed by adopting a bracket method and a synchronous construction scheme for the two side tower columns, a bracket system is installed on the tower body, the cross-beam bracket system comprises embedded parts, corbelling steel brackets, bearing beams, square woods and bottom molds, the steel plates are connected to the tower wall through bolts by the embedded parts, the corbelling steel brackets are welded with the embedded steel plates, and the cross-beams adopt a layered pouring mode. The application effectively solves the construction of the large-inclination no-under-cross-beam bridge tower, gives a specific and reasonable tower column construction method according to the characteristics that the cable tower is a large-inclination space structure, the cable tower has a large inclination angle, the tower column construction active cross brace bears a large force, and high-altitude installation is difficult, effectively simplifies the process, makes the processes mutually cooperate, effectively improves the construction efficiency and quality, provides a reference for similar projects, and has a high popularization value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge construction, in particular to a construction method of a large-inclination non-under-beam bridge tower. BACKGROUND

[0002] As a cable system, the cable-stayed bridge has a larger span than the beam bridge, and is the main bridge type of large-span bridges. The cable-stayed bridge is a bridge in which a beam is pulled on a tower column by a plurality of cables. The cable-stayed bridge is a self-anchored system, and the horizontal force of the cable is borne by the beam. The beam is supported on the piers as well as on the cables drawn from the tower column. According to the materials used for the beam, the cable-stayed bridge can be divided into a steel cable-stayed bridge, a composite beam cable-stayed bridge and a concrete beam cable-stayed bridge. The cable-stayed bridge mainly consists of a bridge tower, a main beam and cables. In the construction process of the bridge tower, based on many factors such as aesthetics, some cable-stayed bridges have an "A" shaped structure without an under-beam. The tower column of this kind of bridge tower is a tilted space structure, and the positioning precision of the tower column line, the cable guide pipe and the steel anchor beam is high. The measurement and construction monitoring are difficult, the inclination angle of the tower column is large, the stress of the active cross brace of the tower column is large, and the high-altitude installation is difficult. Moreover, the tower column construction process is complicated, the processes intersect with each other, and the risk of high-altitude operation is large. At present, there is no systematic construction method for this kind of large-inclination non-under-beam bridge tower, and a more general construction method is urgently needed for reference in future similar projects. SUMMARY

[0003] In order to solve the problems existing in the prior art, a construction method of a large-inclination non-under-beam bridge tower is provided.

[0004] The technical scheme adopted by the present application to solve the technical problems is:

[0005] The present application provides a construction method of a large-inclination non-under-beam bridge tower, comprising:

[0006] S1: lower tower column construction, the solid section is poured together with the tower base using a wooden formwork, and from the second section, hydraulic climbing formwork is used for construction in cooperation with formwork turning, at the same time, the icebreaker and bracket stiffening rib are constructed using a support in cooperation with a steel formwork;

[0007] S2: middle tower column construction, after the lower tower column construction is completed, the lower tower column climbing formwork is converted into a middle tower column climbing formwork for construction, then the middle tower column climbing formwork is constructed, the formwork is used for climbing formwork construction except that the special-shaped section inner formwork uses a common wooden formwork, a horizontal cross brace for offsetting the horizontal force generated by the inward inclination of the tower column is arranged on the inner side of the middle tower column, and the horizontal cross brace is removed after the tower column closing section construction is completed;

[0008] S3: After the middle tower column construction is completed, the middle tower column climbing form is converted into the upper tower column climbing form construction, the upper tower column climbing form construction method is the same as the middle tower column construction method, the outer form of the upper tower column uses the climbing form, the inner form uses the climbing form except that the special-shaped section inner form uses the ordinary wood form, during the upper tower column construction, the control cable guide pipe is positioned and the steel anchor beam is installed and constructed, the steel anchor beam is installed in place by using the tower crane, and the pre-lifting amount is set during the upper tower column construction;

[0009] S4: The upper beam construction, the main tower upper beam adopts the bracket method and the two side tower columns adopt the synchronous construction scheme, the bracket system is installed on the tower, the beam bracket system includes the embedded part, the bracket-shaped steel bracket, the bearing beam, the square wood and the bottom form, the embedded part connects the steel plate on the tower wall through the bolt, the bracket-shaped steel is welded with the embedded steel plate, and the beam adopts the layered pouring mode.

[0010] Preferably, in S1, during construction, the first section of the lower tower column solid section is first poured, the climbing form upper frame is installed during the construction of the second section, the second section of the tower column is completed, after the second section of the tower column construction is completed, the climbing form is climbed, the hanging platform is installed, and the climbing form and the turnover form are used for the construction of the remaining sections of the lower tower column, and the upstream side tower column starts to install the climbing form at the third section;

[0011] The main tower steel bars are processed on the shore steel bar processing plant, the vertical and horizontal steel bars of the main tower are bound and formed in the processing plant, the number and position of the reserved joints are reserved according to the design and specification requirements, the flat car is used for transfer to the site, the tower crane is used for hoisting to the construction area, and the installation is carried out, the tower column steel bars are positioned by using the stiff skeleton, the stiff skeleton is processed in sections, and is installed in sections and pieces, the stiff skeleton is installed once, and a section is constructed, and the climbing frame is climbed once.

[0012] Preferably, in S3, after the cable tower concrete is completely poured and the steel anchor beam is installed in place, the cable tower anchoring area prestress is tensioned, the upstream and downstream tower columns are parallel during tensioning, after the cable tower concrete is completely poured and the steel anchor beam is installed in place, the climbing form system is removed and reinstalled to the upper tower column first section to start the tensioning and grouting work of the cable anchoring area prestress, the upper tower column prestressed steel bars are divided into ring direction prestressed steel bars and inner side bridge direction prestressed steel bars, and the prestressed steel bars in the closing section are bridge direction and transverse bridge direction prestressed steel bars.

[0013] Preferably, in S4, the beam prestressed steel strands are simultaneously tensioned at both ends, the outer side tensioning bracket pre-embedded parts are embedded in advance during the beam construction, the outer side bracket is welded after the completion of the beam construction, forming a tensioning and grouting work platform, the tensioning sequence of the prestressed steel strands is: first from the middle of the web to the upper and lower edges in turn, the prestressed steel strands at the same height on both sides of the web should be symmetrically tensioned, and then from the middle of the top plate and the bottom plate to the left and right symmetrically tensioned. When tensioning, double control is adopted for the control of tensioning force and elongation, the actual elongation value and the theoretical elongation value are controlled within ± 6%, the broken wire rate should not exceed the specification requirement, and attention should be paid to the pre-embedding of manhole doors, power pipeline holes, various pre-embedded parts and pre-embedded steel during the beam construction.

[0014] Preferably, the tower column construction sequence is: the first to fifth sections of the tower column are constructed by using the outer side climbing form, the inner side is constructed by cooperating with the support and the steel form, the sixth to nineteenth sections are constructed by using the climbing form, the cable guide pipe positioning and installation are performed in advance when the construction is performed to the sixteenth section, the upper beam triangular bracket construction is performed after the eighteenth section is constructed, the inner side form of the climbing form is removed after the climbing form is climbed to the twentieth section, the upper beam steel form construction is performed, and the upper beam is constructed synchronously with the twentieth section.

[0015] Preferably, the specific construction method comprises:

[0016] S11: the tower base and the tower base starting section are poured, the climbing form and the corbel and the stiffening rib formwork are installed, the first to seventh sections of the tower column are poured, the corbel and the stiffening rib are constructed at the same time, the first horizontal support is installed after the climbing form is climbed to the eighth section of the tower column;

[0017] S12: after the tenth section of the tower column is poured and the climbing form is climbed to the eleventh section of the tower column, the second horizontal support installation is started, the thirteenth section of the tower column is poured, the third active support rod installation is started after the climbing form is climbed to the fourteenth section, the fourteenth section of the tower column is poured, and the cable guide pipe installation is performed in advance;

[0018] S13: the sixteenth section of the tower column is poured, the fourth horizontal support frame installation is started after the climbing form is climbed to the seventeenth section, the sixteenth section of the tower column is poured, the cable guide pipe installation is performed in advance, the nineteenth section of the tower column is poured, the fifth horizontal support frame installation is started after the climbing form is climbed to the twentieth section, and the upper beam triangular bracket installation is started;

[0019] S14: the twentieth section of the tower column is poured, the inner side form of the climbing form is removed, the upper beam steel form is installed, the upper beam is constructed, the steel anchor beam installation is performed in advance after the twentieth section of the tower column is poured, the first tower limb is poured and the first tower limb climbing form is removed, then the second tower limb is poured and the second tower limb climbing form is removed.

[0020] The preferred tower column reinforcement installation sequence is: main reinforcement, stirrup, tie, and anti-cracking net reinforcement. The main reinforcement is precisely positioned by the positioning frame on the rigid skeleton, and then connected by straight thread sleeve after being placed one by one. The stirrup and tie are positioned and bound by the main reinforcement;

[0021] The beam reinforcement installation sequence is: bottom plate bottom layer reinforcement, bottom plate top layer reinforcement, bottom plate tie, web reinforcement, top plate bottom layer reinforcement, top plate top layer reinforcement, and top plate top layer tie.

[0022] Before installing the bottom layer reinforcement, the longitudinal and transverse axes of the beam are measured, and then the position of the bottom layer reinforcement is marked on the formwork with red paint. The reinforcement is bound in sequence according to the line. When installing the reinforcement, the joints should be staggered, and the joint area of the reinforcement in the same section should not be greater than 50%.

[0023] The preferred hydraulic self-climbing formwork adopts a split hydraulic climbing formwork, and the formwork and the frame are independent of each other. The formwork does not move during climbing, erecting, demolding, and working period construction protection platform. The split hydraulic climbing formwork system includes a formwork system, a rear-moving support, a platform support, a buried part system, a hydraulic system, and a guide rail. Each platform from top to bottom is: a reinforcement binding platform for binding reinforcement during construction, a formwork operation platform for formwork construction operation, a formwork operation platform for formwork movement and serving as a main personnel channel, a hydraulic operation platform for hydraulic system operation during climbing, a hanging platform for the use of hanging seats, climbing cones, and force bolts for easy disassembly and turnover.

[0024] The preferred construction process includes: during the construction process, the hydraulic climbing formwork is used as a common formwork for construction during the construction of the first to third sections. The climbing formwork is removed and climbed using a tower crane or a crane. When the construction reaches the fourth section, the outer climbing formwork has a self-climbing function. When the construction reaches the fifth section, the inner climbing formwork is installed. The construction reaches the sixth section with a partial self-climbing function. At this point, the hydraulic climbing formwork system normally climbs and constructs. The hydraulic climbing formwork climbing process for each section is: concrete pouring, formwork removal and movement after pouring, installation of attached wall devices, lifting of guide rails, climbing of frame, binding of reinforcement, cleaning of formwork with demolding agent, fixation of embedded parts on the formwork, formwork assembly, and concrete pouring.

[0025] The preferred climbing method of the hydraulic climbing formwork includes:

[0026] Guide rail climbing: when the concrete strength reaches the specified requirement, the upper climbing suspension is installed, the climbing guide rail is cleaned, the surface of the guide rail is coated with lubricating oil, and the direction of the upper and lower jacking devices of the hydraulic cylinder is consistent and upward.

[0027] After confirming that the climbing conditions are met, the oil inlet valve of the hydraulic cylinder is opened, the hydraulic control cabinet is started, the guide rail top pin is removed, and the guide rail climbing begins.

[0028] When the guide rail is jacked into place, the climbing guide rail top plug is inserted from right to left, and the descending guide rail top plug is fully contacted with the suspension piece;

[0029] After the guide rail climbing is completed, the oil cylinder oil inlet valve is closed, the control cabinet is closed, and the power supply is cut off;

[0030] Climbing of the climbing frame body and the formwork: after the guide rail climbing is completed, the climbing of the climbing frame body and the formwork is carried out, and the process is as follows: cleaning the load on the climbing frame, changing the state of the hydraulic oil cylinder up and down jacking spring device to be consistent downward, releasing the connecting piece of the tower column and the climbing frame, loosening the pressure screw rod, removing the locking plate, retreating the pressure screw rod, and completing the front segment concrete bolt hole repair.

[0031] Compared with the prior art, the beneficial effects of the present application are:

[0032] The present application effectively solves the construction of the large-inclination no-under-beam bridge tower, and gives a specific and reasonable tower column construction method according to the characteristics of the inclined space structure of the cable tower, high positioning precision requirement of the tower column line type, cable guide pipe and steel anchor beam, great difficulty in measurement and construction monitoring, large inclination angle of the cable tower, large stress of the active cross brace of the tower column construction, and great difficulty in high-altitude installation, effectively simplifies the process, makes mutual cooperation between the processes, effectively improves the construction efficiency and quality, can realize the construction of the large-inclination no-under-beam bridge tower, provides reference for similar projects, and has very high popularization value. BRIEF DESCRIPTION OF DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

[0034] Figure 1 is a schematic diagram of the overall structure of the present application;

[0035] Figure 2 is a process flow diagram of the lower tower column construction process in the present application;

[0036] Figure 3 is a process flow diagram of the middle tower column construction process in the present application;

[0037] Figure 4 is a process flow diagram of the upper tower column construction process in the present application;

[0038] Figure 5 is a process flow diagram of the upper beam construction process in the present application;

[0039] Figure 6 is a tower column segmentation diagram in the present application;

[0040] Figure 7 is the overall construction process in the present application Figure 1 ;

[0041] Figure 8 is the overall construction process in the present application Figure 2 ;

[0042] Figure 9 is the overall construction process in the present application Figure 3 ;

[0043] Figure 10 is the overall construction process in the present application Figure 4 ;

[0044] Figure 11 is the overall construction process in the present application Figure 5 ;

[0045] Figure 12 is the overall construction process in the present application Figure 6 ;

[0046] Figure 13 is the overall construction process in the present application Figure 7 ;

[0047] Figure 14 is the overall construction process in the present application Figure 8 ;

[0048] Figure 15 is the overall construction process in the present application

[0049] Figure 16 is the overall construction process in the present application

[0050] Figure 17 is the overall construction process in the present application

[0051] Figure 18 is the overall construction process in the present application

[0052] Figure 19 is the overall construction process in the present application DETAILED DESCRIPTION

[0053] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for the purpose of explaining the present application, and cannot be understood as limiting the present application.

[0054] As shown in Figures 1-19 , the present embodiment proposes a construction method of a large-dip-angle bridge tower without lower beam, comprising:

[0055] S1: lower tower column construction, solid section start 50 cm using wood formwork with tower seat pouring, from the second section using hydraulic climbing form with turnover form construction, at the same time, icebreaker and bracket stiffening rib construction, using support with steel formwork;

[0056] During construction, first pouring the first section of the lower tower column solid section, installing the climbing form upper frame body when the second section is constructed, completing the second section tower column construction, after the second section tower column construction is completed, the climbing form is climbed, installing the hanging platform, using the climbing form and turnover form for the remaining section of the lower tower column construction, the upstream side tower column starts installing the climbing form at the third section.

[0057] The main tower reinforcement is processed on the shore reinforcement processing workshop, the vertical and horizontal reinforcement is bound and formed in the processing workshop, the number and position of the reserved joints are reserved according to the design and specification requirements, and the flat car is used for transfer to the site, the tower crane is used for hoisting to the construction area for installation, the tower column reinforcement is positioned by using the stiff skeleton, the stiff skeleton is processed in sections, and is installed in sections and pieces, the stiff skeleton is installed once, and a section is constructed, and the climbing frame is climbed once.

[0058] The vertical stiff skeleton adopts ∠100×100×10mm angle steel, and the horizontal connection and vertical diagonal brace all adopt ∠75×75×8mm angle steel.

[0059] S2: middle tower column construction, after the lower tower column construction is completed, the lower tower column climbing form is converted into the middle tower column climbing form construction, then the middle tower column climbing form construction is carried out, the horizontal cross brace is arranged on the inner side of the middle tower column for offsetting the horizontal force generated by the tower column inward inclination, and the horizontal cross brace is removed after the tower column closing section construction is completed;

[0060] S3: upper tower column construction, after the middle tower column construction is completed, the middle tower column climbing form is converted into the upper tower column climbing form construction, the upper tower column climbing form construction method is the same as that of the middle tower column construction, the upper tower column outer form adopts the climbing form, and the inner form adopts the ordinary wood form except that the inner form of the special-shaped section adopts the ordinary wood form, during the upper tower column construction, the control cable guide pipe positioning and steel anchor beam installation construction are carried out, the steel anchor beam is installed in place by using the tower crane, considering the influence of the shrinkage and creep of concrete and the elastic deformation of the tower column, in order to ensure the accuracy of the cable tower anchoring position, the pre-lifting amount is set during the upper tower column construction.

[0061] In S3, after the cable tower concrete is completely poured and the steel anchor beam is installed in place, the cable tower anchoring area prestress is tensioned again, the upstream and downstream tower columns are parallel during tensioning, after the cable tower concrete is completely poured and the steel anchor beam is installed in place, the climbing form system is removed and reinstalled to the upper tower column first section, and the tensioning and grouting work of the cable anchoring area prestress is carried out, the prestressed steel bundle in the upper tower column is divided into ring direction prestressed steel bundle and inner side bridge direction prestressed steel bundle, and the prestressed steel bundle in the closing section is bridge direction and transverse bridge direction prestressed steel bundle.

[0062] S4: Construction of the upper crossbeam. The upper crossbeam of the main tower adopts the bracket method and the construction scheme of the two side tower columns are carried out simultaneously. The bracket system is installed on the tower body. The crossbeam bracket system includes embedded parts, corbel steel brackets, load-bearing beams, square timber and bottom formwork. The embedded parts connect the steel plates to the tower wall with bolts. The corbel steel is welded to the embedded steel plates. A total of 4 sets of corbel steel brackets are set. The crossbeam adopts the layered casting method.

[0063] In S4, the prestressed steel strands of the crossbeam are tensioned simultaneously from both ends. During the construction of the crossbeam, the pre-embedded parts of the outer tensioning bracket are embedded in advance. After the construction of the crossbeam is completed, the outer bracket is welded to form a tensioning and grouting working platform. The tensioning sequence of the prestressed strands is as follows: first, from the middle of the web plate upwards and then from the lower edge, the prestressed steel strands at the same height on both sides of the web plate should be tensioned symmetrically, and then from the middle of the top and bottom plates to the left and right symmetrically.

[0064] The design anchor tension control force for each bundle of steel strands is 3710.7KN. During tensioning, dual control is adopted for tension force and elongation. The actual elongation value and the theoretical elongation value are controlled within ±6%. The wire breakage rate must not exceed the specification requirements. When constructing the crossbeam, pay attention to the pre-embedded manholes, power line holes, various pre-embedded parts and pre-embedded steel.

[0065] The main tower is divided into 24 segments, each 6 meters long. The lower tower has 4 segments, the middle tower has 15 segments, and the upper tower has 5 segments. The longest segment is 6 meters and the shortest segment is 2.894 meters.

[0066] The construction sequence of the tower column is as follows: the construction of the tower column sections 1-5 adopts the outer climbing formwork, and the inner side is constructed in conjunction with the support and steel formwork. The standard stage of sections 6-19 uses climbing formwork construction. When the construction reaches the 16th stage, the cable guide pipe is positioned and installed in advance. After the 18th section is completed, the upper crossbeam triangular bracket is constructed. After the climbing formwork is raised to the 20th section, the inner formwork of the climbing formwork is removed, and the upper crossbeam reinforcement formwork is constructed. The upper crossbeam is constructed simultaneously with the 20th section.

[0067] like Figures 7-14 As shown, the overall construction process flowchart is disclosed, and the specific construction methods include:

[0068] S11: Construct the tower base and the starting section 0.5m above the tower base, install the climbing formwork and corbel and its stiffening rib formwork, complete the pouring of the first to seventh sections of the tower column, construct the corbel and its stiffening rib at the same time, and after the climbing formwork is raised to the eighth section of the tower column, install the first horizontal brace.

[0069] S12: After the 10th section of the tower column is poured and the climbing formwork is raised to the 11th section of the tower column, the second horizontal support installation will begin. After the tower column is poured to the 13th section and the climbing formwork is raised to the 14th section, the third active strut installation will begin. After the tower column is poured to the 14th section, the cable guide pipe will be installed in advance.

[0070] S13: Tower column pouring to 16 sections, waiting for the climbing form to climb to the 17th section, starting the fourth transverse support frame installation, the tower column pouring to 16 sections, the installation of the cable guide pipe is advanced, the tower column pouring to 19 sections, waiting for the climbing form to climb to the 20th section, starting the fifth transverse support frame installation, the upper beam triangular bracket installation;

[0071] S14: Tower column pouring to 20 sections, removing the inside formwork of the climbing form, installing the upper beam steel formwork, constructing the upper beam, installing the steel anchor beam in advance when the tower column pouring to 20 sections, pouring the 1# tower limb and removing the climbing form of the 1# tower limb, then, pouring the 2# tower limb and removing the climbing form of the 2# tower limb.

[0072] The main reinforcement of the main tower adopts hot-rolled HRB400 steel bars with a diameter of 32mm, adopts stripped rib rolling straight thread sleeve mechanical connection, and the thread heads all adopt standard length thread heads, that is, the length of the thread head is equal to half of the length of the connecting sleeve. The ring reinforcement adopts hot-rolled HRB400 steel bars with a diameter of 20mm, and 1 layer of galvanized steel wire mesh with a diameter of 6mm and a spacing of 10cm*10cm is arranged close to the outermost layer of steel bars.

[0073] The steel bars are cut according to the design joint position, and the cutting is performed by an electric grinding wheel cutting machine. When the steel bars are cut, the cut end of the steel bar should be perpendicular to the axis of the steel bar, and there should be no horse hoof-shaped or warped end.

[0074] Adjust the minimum size of the inner hole of the thread rolling head and the expansion ring according to the size of the steel bar, adjust the position of the stripped rib stop block and the rolling travel switch, and ensure the length of the stripped rib and the rolled thread.

[0075] When processing the threads of the steel bars, water-soluble cutting lubricating liquid is used; when the air temperature is lower than 0℃, 15% to 20% of sodium nitrite should be added, and machine oil should not be used as lubricating liquid or no lubricating liquid should be added.

[0076] Check the appearance quality of the steel bar thread one by one, check whether the tooth shape is full, whether there are broken teeth, and whether there are defects such as bare teeth, and the qualified thread is covered with a protective cap for protection.

[0077] The threading of the steel bars and the threading of one end of the thread sleeve are all completed in the rear field. For the steel bars with threads on both ends, one end is threaded with a thread sleeve and covered with a sleeve cover, and the other end is protected by a plastic protective sleeve. After the steel bars are transported to the front field and installed in place, the connection is completed at the installation site using a pipe wrench.

[0078] In order to ensure the smooth connection of the steel bars, the processed steel bars should be protected during transportation and hoisting, especially the exposed threads of the steel bars and the internal threads of the sleeve. The processed semi-finished products are first transported to the steel trestle by a flat car, and then hoisted into the climbing form by a crane.

[0079] Steel bars at intersections are connected by binding, using quincunx binding. In the steel bar cutting scheme, the connection of steel bars in the same row is considered, the joints are staggered according to the requirements of the specification, and attention is paid to the placement position of different types of steel bars during the cutting and binding of steel bars.

[0080] The installation sequence of the tower column steel bars is: main bars, stirrups, tie bars, and anti-cracking mesh steel bars. The main bars are precisely positioned by relying on the positioning frame on the stiff skeleton, and are connected by straight thread sleeves after being placed one by one. The stirrups and tie bars are positioned and bound by using the main bars. The installation sequence of the beam steel bars is: bottom plate bottom layer steel bars, bottom plate top layer steel bars, bottom plate tie bars, web steel bars, top plate bottom layer steel bars, top plate top layer steel bars, and top plate top layer tie bars.

[0081] Before installing the bottom layer steel bars, the longitudinal and transverse axes of the beam are measured, and then the position of the bottom layer steel bars is marked on the formwork with red paint. The steel bars are bound in sequence according to the line, to ensure the spacing, position, and straightness of the steel bars. When installing the steel bars, attention should be paid to staggering the joints, and the joint area of the steel bars in the same section should not be greater than 50%.

[0082] During the construction of the main tower body, due to the design of the tower body being inclined in the transverse bridge direction, the steel bars are not sufficient to support themselves, so it is necessary to install a stiff skeleton to bear the load of the steel bars. The stiff skeletons are placed in both tower limbs.

[0083] The stiff skeleton is composed of small trusses and connecting systems between the trusses. The small trusses use ∠1000×10mm angle steel as the vertical rod, and ∠75×8mm angle steel as the horizontal rod inside the truss and the upper and lower inclined braces, forming a frame system with a rectangular cuboid outer contour. One small truss is arranged on each side of a single tower limb (not arranged on the chamfered side), and ∠75×8mm angle steel is used for the connection between the small trusses. According to the sectional length of the tower limb, the standard sectional length of the stiff skeleton is 6m.

[0084] According to the sectional height of the tower column pouring and the cantilever length of the main bars, the standard of the stiff skeleton is processed according to the height of 6m. The connection between the stiff skeletons is welded, and the welding is full to ensure the stability of the connection between the steel bars. To facilitate transportation and on-site positioning and installation, the stiff skeleton is processed into a small section truss structure form in the rear field.

[0085] Rectangular small section truss initial positioning: when the stiff skeleton is initially positioned by lengthening on site, a short angle steel of the same type is attached to the inside of the top angle steel of the installed truss as a skeleton bottom opening installation positioning code. The vertical ball and the ruler are used to control the position of the top opening of the skeleton, that is: the tower crane lifts the truss, and the bottom corner of the truss is tightly positioned against the short angle steel. The measurement personnel select the appropriate position according to the specific situation, suspend the vertical ball, and guide the adjustment according to the measurement results. When the position of the truss meets the requirements, the truss is immediately welded with the positioning angle steel.

[0086] Construction of horizontal bracing and inclined bracing: after the lengthening and welding of the stiffened skeleton small-section truss, the horizontal positioning angle steel is welded, the horizontal position line of the main reinforcement on both sides is located by placing points on the positioning angle steel and small-section truss, then the horizontal bracing is installed and welded according to the position line of the reinforcement, and the inclined bracing is welded.

[0087] The tower limb is segmented and a 0.5m high starting section is set, the starting section includes the tower limb and the 0.5m high range of the bracket stiffening rib, and the starting section is poured together with the tower base.

[0088] The 0.5m high starting section of the tower limb is a solid structure, which is inconvenient for using the hydraulic self-climbing formwork. The formwork is made of high-quality bamboo plywood, and the installation and reinforcement of the formwork are carried out according to the design size. The formwork is made of 1.5cm thick high-quality bamboo plywood, the vertical backband is made of 10*10cm square wood with a spacing of 30cm, the horizontal backband is made of double-piled φ48*3mm steel pipes, the pull rod is made of a custom-made threaded rod, and the reinforcement is made of 10*10*1cm steel gasket double nuts. The straight line of the arc inside the starting section stiffening rib has a theoretical error of 4mm, and the straight line is used instead of the curve in this section.

[0089] Formwork construction of sections 1-4: the length of section 1 is 5.95m, and the formwork is made of factory-ordered steel formwork due to the variable shape of the tower limb inside the tower body along the bridge direction (including the stiffening rib). The height of the formwork on the arc side of the stiffening rib is 6m, and the width is 3.0m; the height of the formwork on the horizontal bridge direction of the stiffening rib is 5.95m; three sections of inverted angle formwork are arranged on the tower body and its vicinity. The face plate is made of 5mm thick steel plate, the vertical rib is [8# channel steel, and the horizontal rib is double-piled [14# channel steel. The other faces of the tower limb are made of climbing formwork VISA plate + wooden I-beam + [14 type steel backband structure. The icebreaking body on the upstream side uses the icebreaking body steel plate as the formwork face plate, and the pull and external support back rib are arranged outside the steel plate to ensure the stability of the formwork.

[0090] A disc buckle support construction platform is set up around the tower column to meet the needs of formwork turnover construction. The D20 pull rod and D20 butterfly nut pre-buried in the starting section are used to install the anchor seat, vertically support and press the bottom of the formwork of section 1 on the starting section concrete.

[0091] The length of section 2 is 5.95m, and the formwork is still supported by the turnover method along the bridge direction inside the tower column (including the stiffening rib); before installing the formwork of section 2, the climbing frame system pre-buried parts are installed, and then the climbing formwork is installed as the outer formwork. The icebreaking iron steel plate is used as the formwork on the variable slope section of the icebreaking body, and the supporting rib is arranged inside the tower column, which is welded on the stiffened skeleton. Other construction processes are the same as those of section 1.

[0092] The 2nd segment stiffening rib extends 2.98m out of the bridge, and a type steel is used to erect the stiffening rib cast-in-place support. The support is provided with 4 steel columns, the bottom of the column is welded with a steel plate, the bottom is constrained by the tower column, tower base embedded reinforcement, and the upper part is constrained by the tower limb embedded part welded with a type steel; the top of the column is provided with a steel main beam in the longitudinal direction of the bridge, and 5 groups of 2I36 type steel distribution beams are arranged along the angle of the stiffening rib; a wedge-shaped block is used to support the stiffening rib steel formwork 2[14 back ridge. The front and rear side formworks of the 2nd segment stiffening rib are vertically supported and compressed at the bottom; in addition, the support is used to support the bottom of the extended formwork. A 5mm thick sponge rubber belt is attached along the concrete joint line, and the formwork is installed with a 0.1m lower package.

[0093] The 3rd segment is 2.894m long, and the extended tower column is inside the scaffold along the bridge. The corbel is 4.5m high and 5.0m wide, and the corbel extends 1.0m out of the stiffening rib in front of and behind the bridge. The corbel cast-in-place support is erected, and 8 vertical rods are provided, the vertical rods are made of spiral steel pipes; the connection system between the vertical rods is made of 20a channel steel connection; 4 double-spliced I25 steels are arranged on the pile top cross beam; the cross beam is provided with I20 distribution beams in the longitudinal direction of the bridge, and 8mm thick steel plates are welded thereon with an interval of 30cm; then, square wood is arranged. The front and rear side supports are connected by using channel steel, and the supports are longitudinally constrained by using the tension rod. Except for the corbel side, the tower column is constructed by using the climbing formwork, the climbing formwork is climbed to the 3rd segment by using the pre-embedded part installed in the previous segment, a hoisting platform is installed, and the climbing formwork has self-climbing ability.

[0094] The 4th segment is 4.56m long, and the tower column is inside the scaffold along the bridge. The other surfaces of the climbing formwork continue to climb to the 4th segment. After the 4th segment is poured, the climbing formwork pre-embedded part is used to install a triangular frame body, a hydraulic system and a climbing frame on the inside along the bridge, so that it has a preliminary self-climbing ability.

[0095] The 5-24 segments are constructed by using the self-climbing formwork, and the inside climbing rail along the bridge is adjusted once according to the design line shape when entering the 20th segment. The tower column and the upper tower column are constructed by using the asynchronous method, because the space between the two tower limbs is limited, the single-sided tower limb is constructed first, and then the climbing and pouring of the climbing formwork of the other side tower limb are carried out.

[0096] The hydraulic self-climbing formwork is a separated hydraulic climbing formwork, the formwork and the frame body are independent of each other, the formwork does not move during climbing, supporting, demolding and construction protection platform during work, the separated hydraulic climbing formwork system includes a formwork system, a rear support, a platform support, an embedded part system, a hydraulic system and a guide rail, and each platform is from top to bottom: a steel reinforcement binding platform for binding steel reinforcement during construction, a formwork operation platform for formwork construction operation, a formwork operation platform for formwork rear movement and as a main personnel channel, a hydraulic operation platform for hydraulic system operation during climbing formwork climbing, a hanging platform for convenient disassembly and turnover of a hanging seat, a climbing cone and a force bolt.

[0097] Inner formwork of tower column: the size of lower inner cavity of tower column is small and the shape changes frequently. The size of inner cavity chamfer section is constant, so the chamfer position is made into a fixed steel formwork, and the edge of chamfer steel formwork is provided with 2-3 cm pressing formwork to better ensure the quality of joint. The remaining large surface formwork is a steel-wood combined formwork, the vertical rib is 10x10 cm square wood with a spacing of 30 cm, and the back ridge is double-spliced [14 channel steel with a vertical spacing same as the climbing formwork formwork to facilitate the installation of φ20 opposite pull rods. The planar size of straight section formwork is adjusted accordingly with the change of tower column height.

[0098] The cross section of upper tower column inner cylinder changes little, and the wood beam formwork of climbing formwork is configured to realize the synchronous lifting of inner formwork and outer formwork through tower crane. Steel membrane is used at small chamfer and corner, and wood beam formwork is used at plane. When necessary, the wood beam formwork is cut at both sides, and the inner formwork only needs to re-drill pull rod holes at the climbing surface. After the construction of the 5th section is completed, the wood beam formwork can be installed in the 6th section inner cylinder, and the inner and outer formworks are pulled to resist the lateral pressure of concrete in the pouring state. The inner and outer climbing formwork systems are used to complete the construction of the 6th to 15th sections of tower column. The 16th to 23rd sections enter the cable guide pipe area, and the inner formwork is constructed by square wood + bamboo plywood. A conical joint is pre-buried on the upper mouth of the formwork during each pouring to serve as the lower mouth of the formwork for the next pouring.

[0099] The inner cylinder of upper tower column is used as a formwork for the steel anchor beam pre-buried plate in the horizontal bridge direction, and the climbing formwork wood beam formwork is used for the width-invariant longitudinal bridge direction.

[0100] The inner cavity is constructed by the method of inner shaft cylinder platform. The total height is about 8.5 m, which is mainly composed of working platform and anchoring suspension components. The platform frame is made of small steel, and 2 layers of platforms are set, including 1 hoisting platform and 1 main working platform. The platform is fixed on the pre-buried anchor cone in the inner cavity of tower limb through support assembly. The lifting of shaft platform adopts tower crane lifting. During the construction of the previous section, the shaft platform anchor cone used for the construction of the next section is pre-buried. After the removal of the concrete formwork of the previous section, the shaft platform is lifted by the crane and placed in the cavity of tower limb, and the platform assembly is installed. The wood beam with a spacing of 35 cm is arranged on the platform assembly, and the bottom plate is laid as the inner formwork standing platform, and at the same time, the inner cavity bottom forms a closed structure, and the inner formwork of the next section is constructed on the shaft platform.

[0101] The inner climbing formwork of main tower column is a wood formwork except for the chamfer position which is a steel formwork. The inner formwork adopts a turnover formwork construction and forms a high-strength screw rod with the outer climbing formwork to pull.

[0102] When the next tower column is constructed, the pre-buried part is pre-buried to facilitate the fixation of inner formwork during the construction of the next tower column. The inner formwork size changes with the construction of tower column, and the inner formwork is always synchronized with the lifting of the outer hydraulic self-climbing formwork of main tower column.

[0103] The connection and fixation of the inner and outer formwork of the main tower are both done using tie rods. There are two types of tie rods: one is for connecting the inner and outer formwork, and the other is for connecting the outer formwork.

[0104] Figure 18 This is a schematic diagram of the climbing formwork process in this invention, as shown below. Figure 18 As shown, the construction process includes: During the construction of sections 1-3, the hydraulic climbing formwork is used as ordinary formwork, and tower cranes or cranes are used for dismantling and climbing operations. When the construction reaches section 4, the outer climbing formwork has the function of self-climbing. When the construction reaches section 5, the inner climbing formwork is installed. When the construction reaches section 6, the partial self-climbing function is achieved. At this point, the hydraulic climbing formwork system is in normal climbing construction. The climbing process of the hydraulic climbing formwork for each section is as follows: concrete pouring is completed, formwork is dismantled and moved, wall-mounted devices are installed, lifting guide rails are installed, climbing frame is installed, steel bars are tied, formwork is cleaned and release agent is applied, embedded parts are fixed to the formwork, formwork is closed, and concrete is poured.

[0105] The climbing methods of hydraulic climbing formwork include:

[0106] Guide rail climbing: When the concrete strength reaches the specified requirements, the upper climbing suspension is installed, the climbing guide rail is cleaned, the guide rail surface is coated with lubricating oil, and the upper and lower lifting devices of the hydraulic cylinder are aligned upwards.

[0107] After confirming that the climbing conditions are met, open the oil inlet valve of the hydraulic cylinder, start the hydraulic control cabinet, remove the top pin of the guide rail, and begin the climbing of the guide rail.

[0108] Once the guide rail is in position, insert the top pin of the climbing guide rail from right to left until the top pin of the descending guide rail is in full contact with the suspension components.

[0109] After the guide rail has climbed, close the oil inlet valve of the hydraulic cylinder, shut down the control cabinet, and disconnect the power supply.

[0110] Climbing of the scaffolding and formwork: After the guide rails are in place, the scaffolding and formwork are lifted. The process is as follows: clear the load on the scaffolding, change the state of the hydraulic cylinder lifting spring device so that they are all pointing downwards, disconnect the connection between the tower column and the scaffolding, loosen the bearing screw, remove the locking plate, retract the bearing screw, and complete the repair of the concrete bolt holes of the previous section.

[0111] Hydraulic climbing formwork demolding: Check that the adjusting screw and the formwork back rib are in full contact, and that the adjusting screw is tightened against the back rib. Loosen the through-wall bolts, then remove the outer formwork. Before demolding the outer wall formwork, be sure to tighten the diagonal brace by 5°, or control the top of the formwork to be 600mm away from the wall surface, ensuring full contact of the rolling surfaces, with the weight of the platform and diagonal brace on the rollers at this point. Clean the debris from the rolling surface of the main beam. Move the outer wall formwork back and immediately insert pins and hairpins into the main beam. Clean the formwork surface and apply a release agent.

[0112] Hydraulic climbing formwork closing: when closing, the inner and outer wall formworks are moved, and the movement of maintaining the backward inclined state of the formwork is paid attention to. The inner and outer wall formworks are moved simultaneously to the same climbing formwork frame, and the verticality of the formwork is adjusted after the inclined brace is rotated. The formwork is not adjusted to be vertical or forward inclined before being moved. The pin and the release are inserted immediately after the outer wall formwork is moved to the position. The inner wall formwork is moved to the position and the wooden wedge is placed.

[0113] The climbing formwork removal process is: removing the last layer, removing the frame above the main platform, moving the formwork backward, removing the formwork, removing the guide rail, removing the lower hanging seat, removing the hydraulic system, removing the lower frame, and removing the hanging seat.

[0114] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A construction method of a large-dip-angle tower without a lower cross beam, characterized in that, Comprise: S1: lower column construction, solid section using wood formwork with tower seat pouring, from the second section using hydraulic climbing form with turnover form construction, while the ice body and bracket stiffening rib construction, using support with steel formwork; S2: middle tower column construction, after the completion of the lower tower column construction, the lower tower column climbing form is converted into the middle tower column climbing form construction, then the middle tower column climbing form construction, the template is different from the ordinary wood formwork in the special-shaped section, the rest are used in the climbing form construction, the horizontal cross brace is set in the middle tower column for offsetting the horizontal force generated by the tower column inward inclination, the horizontal cross brace is removed after the tower column closing section construction is completed; S3: upper tower column construction, after the completion of the middle tower column construction, the middle tower column climbing form is converted into the upper tower column climbing form construction, the upper tower column climbing form construction method is the same as the middle tower column construction method, the upper tower column formwork uses climbing form, the inner formwork uses ordinary wood formwork except the special-shaped section, the control cable guide pipe positioning and steel anchor beam installation construction are controlled when the upper tower column is constructed, the steel anchor beam is installed in place by using tower crane, the upper tower column construction sets the pre-lifting amount; S4: upper beam construction, the main tower upper beam uses the bracket method and the synchronous construction scheme with the two side tower columns, the bracket system of the tower body is installed, the bracket system of the horizontal beam includes embedded parts, bracket steel bracket, bearing beam, square wood and bottom formwork, the embedded parts connect the steel plate on the tower wall through bolts, the bracket steel is welded with the embedded steel plate, the horizontal beam uses the layered pouring method; The tower column construction sequence is: the outer climbing form is used for 1-5 sections of tower column construction, the inner side is constructed with support and steel form, the standard stage is constructed by using climbing form from 6 to 19 sections, the cable guide pipe positioning and installation are performed in advance when the construction is performed to 16 stage, the upper beam triangular bracket construction is performed after the construction of 18 sections is completed, the inner side formwork of the climbing form is removed after the climbing form is climbed to 20 sections, the upper beam steel formwork construction is performed, the upper beam is constructed synchronously with 20 sections; The specific method comprises: S11: the tower seat and tower seat starting section pouring are performed, the climbing form and bracket and its stiffening rib formwork installation is performed, the tower column 1st to 7th section pouring is completed, while the bracket and its stiffening rib is constructed, the first horizontal support installation is performed after the climbing form climbs to the tower column 8th section; S12: after the tower column 10th section pouring is completed and the climbing form climbs to the tower column 11th section, the second horizontal support installation is started, the tower column is poured to 13 sections, the third active support rod installation is started after the climbing form climbs to the 14th section, the tower column is poured to 14 sections, the cable guide pipe installation is performed in advance; S13: the tower column is poured to 16 sections, the fourth horizontal support frame installation is started after the climbing form climbs to the 17th section, the cable guide pipe installation is performed in advance when the tower column is poured to 16 sections, the fifth horizontal support frame installation is started after the climbing form climbs to the 20th section, the upper beam triangular bracket installation is started; S14: the tower column is poured to 20 sections, the inner side formwork of the climbing form is removed, the upper beam steel formwork installation is performed, the upper beam construction is performed, the steel anchor beam installation is performed in advance when the tower column is poured to 20 sections, the 1# tower limb pouring is completed and the 1# tower limb climbing form is removed, then, the 2# tower limb pouring is completed, the 2# tower limb climbing form is removed; The hydraulic self-climbing formwork adopts a separated hydraulic climbing formwork, the formwork and the frame body are independent of each other, the formwork does not move during climbing, erecting, demolding and construction protection platform during work, the separated hydraulic climbing formwork system comprises a formwork system, a rear-moving support, a platform support, a buried part system, a hydraulic system and a guide rail, each platform from top to bottom is: a steel bar binding platform for binding steel bars during construction, a formwork operation platform for formwork construction operation, a formwork operation platform for formwork rear movement and serving as a main personnel channel, a hydraulic operation platform for hydraulic system operation during climbing, a hanging platform for hanging seat, climbing cone and force bolt for convenient disassembly and turnover; The construction process comprises: during the construction process, when the first to third segments are constructed, the hydraulic climbing formwork is used as a common formwork for construction, and a tower crane or a crane is used for dismounting and climbing operation, when the fourth segment is constructed, the outer climbing formwork has a self-climbing function, when the fifth segment is constructed, the inner climbing formwork is installed, the complete self-climbing function is achieved when the sixth segment is constructed, and the hydraulic climbing formwork system normally climbs, the climbing process of the hydraulic climbing formwork of each segment is: after concrete pouring and formwork demolding, the formwork is moved backward, the wall attachment device is installed, the guide rail is lifted, the frame body is climbed, the steel bars are bound, the formwork is cleaned and the demolding agent is brushed, the embedded part is fixed on the formwork, the formwork is closed, and the concrete is poured.

2. The construction method of a large-dip-angle tower without lower beam of a bridge according to claim 1, characterized in that, In S1, during construction, the first segment of the lower tower column solid section is first poured, the upper frame body of the climbing formwork is installed when the second segment is constructed, the second tower column is constructed, after the second segment of the tower column is constructed, the climbing formwork is climbed, the hanging platform is installed, and the lower tower column is constructed by using the climbing formwork and the turnover formwork, and the upper stream tower column starts to install the climbing formwork when the third segment is constructed; The main tower steel bars are processed in a steel bar processing workshop on the bank, the vertical and horizontal steel bars are bound and formed in the processing workshop, the number and position of the joints are reserved according to the design and the specification requirements, the flat car is used for transfer to the site, the tower crane is used for hoisting to the construction area, installation is performed, the tower column steel bars are positioned by using the stiff skeleton, the stiff skeleton is processed in sections, and is installed in sections and pieces, the stiff skeleton is installed once, and one segment is constructed, and the climbing frame is climbed once.

3. The construction method of a large-dip-angle tower without lower beam of a bridge according to claim 1, characterized in that, In S3, after the cable tower concrete is completely poured and the steel anchor beam is installed in place, the prestress of the cable tower anchoring area is tensioned, the upper and lower stream tower columns are parallel during tensioning, after the cable tower concrete is completely poured and the steel anchor beam is installed in place, the climbing formwork system is dismounted and reinstalled to the first segment of the upper tower column to start tensioning and grouting of the prestress of the cable anchoring area, the prestress steel bars in the upper tower column are divided into ring direction prestress steel bars and inner side bridge direction prestress steel bars, and the prestress steel bars in the closure section are bridge direction and transverse bridge direction prestress steel bars.

4. The construction method of a large-dip-angle tower without lower beam of a bridge as claimed in claim 1, wherein In S4, the prestressed steel beam is tensioned at both ends simultaneously, the outer tensioning bracket pre-embedded parts are embedded in advance during the construction of the beam, and the outer bracket is welded after the completion of the beam construction to form a tensioning and grouting work platform. The tensioning sequence of the prestressed steel beam is: first from the middle of the web to the upper and lower edges in turn, the prestressed steel beams at the same height on both sides of the web should be symmetrically tensioned, and then from the middle of the top and bottom plates to the left and right symmetrically tensioned. During tensioning, the tensioning force and elongation are controlled by double control, the actual elongation value and the theoretical elongation value are controlled within ± 6%, the broken wire rate should not exceed the specification requirements, and attention should be paid to the pre-embedded manhole, power pipeline hole, various pre-embedded parts and pre-embedded steel during the construction of the beam.

5. The construction method of a large-dip-angle tower without lower beam of a bridge as claimed in claim 1, wherein The installation sequence of the tower column steel bars is: main reinforcement, stirrup, tensioning reinforcement, and crack prevention net steel bars. The main reinforcement is precisely positioned by the positioning frame on the rigid skeleton, and then connected by straight thread sleeve. The stirrup and tensioning reinforcement are positioned and bound by the main reinforcement. The installation sequence of the beam steel bars is: bottom plate bottom layer steel bars, bottom plate top layer steel bars, bottom plate tensioning reinforcement, web steel bars, top plate bottom layer steel bars, top plate top layer steel bars, and top plate top layer tensioning reinforcement. Before installing the bottom layer steel bars, the longitudinal and transverse axes of the beam are measured, and then the positions of the bottom layer steel bars are marked on the formwork with red paint. The steel bars are bound in turn according to the lines. During steel bar installation, the joints should be staggered, and the joint area of the steel bars on the same section should not be greater than 50%.

6. The construction method of a large-dip-angle tower without lower beam of a bridge as claimed in claim 1, wherein The climbing method of the hydraulic climbing formwork includes: Guide rail climbing: when the concrete strength reaches the specified requirements, the upper climbing suspension is installed, the climbing guide rail is cleaned, the surface of the guide rail is coated with lubricating oil, and the directions of the upper and lower jacking devices of the hydraulic cylinder are consistent upward; After confirming that the climbing conditions are met, the oil inlet valve of the hydraulic cylinder is opened, the hydraulic control cabinet is started, the guide rail top pin is removed, and the guide rail climbing starts; When the guide rail is jacked into place, the guide rail top pin is inserted from right to left, and the guide rail top pin is lowered to fully contact the suspension; After the guide rail climbing is completed, the oil inlet valve of the hydraulic cylinder is closed, the control cabinet is closed, and the power is cut off; Climbing of the climbing frame body and formwork: after the guide rail is jacked into place, the climbing of the climbing frame body and formwork is carried out. The process is: cleaning the load on the climbing frame, changing the state of the upper and lower jacking spring devices to be consistent downward, removing the connection between the tower column and the climbing frame, loosening the pressure screw rod, removing the locking plate, retreating the pressure screw rod, and completing the repair of the concrete bolt hole of the previous segment.

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