阅读说明：本技术 大跨度现浇混凝土拱桥无支架施工方法 (Large-span cast-in-place concrete arch bridge support-free construction method ) 是由 高超然 田海燕 于 2021-09-10 设计创作，主要内容包括：本发明大跨度现浇混凝土拱桥无支架施工方法,属于桥梁工程领域,目的是保障施工的安全性和经济性。将混凝土梁片沿拱桥纵向拼装成左半副拱架单元和右半副拱架单元,相邻两片预制混凝土梁片的顶部铰接；在桥台上安装液压伸缩臂,在液压伸缩臂的外端吊装滚筒；将左半副拱架单元和右半副拱架单元反向卷在对应滚筒外周,并将左右半副拱架单元的首段混凝土梁片插接于拱座上的插接孔内；液压伸缩臂纵向卷推缓升左右半幅拱架单元至中间合拢成整副拱架单元；进行预应力张拉；最后施工拱圈。本发明,全程无需支架,消除了不均匀沉降、支架坍塌等安全风险,大大提高了施工的安全性；节约了支架相关费用,缩减了施工费用及施工周期；结构更优化。(The invention discloses a support-free construction method for a large-span cast-in-place concrete arch bridge, belongs to the field of bridge engineering, and aims to ensure the safety and the economy of construction. Assembling concrete beam pieces into a left half auxiliary arch frame unit and a right half auxiliary arch frame unit along the longitudinal direction of the arch bridge, and hinging the tops of two adjacent precast concrete beam pieces; a hydraulic telescopic arm is arranged on the bridge abutment, and a roller is hoisted at the outer end of the hydraulic telescopic arm; reversely rolling the left half auxiliary arch frame unit and the right half auxiliary arch frame unit on the periphery of the corresponding roller, and inserting the first section of concrete beam piece of the left half auxiliary arch frame unit and the right half auxiliary arch frame unit into the inserting hole on the arch support; the hydraulic telescopic arm longitudinally rolls, pushes, slowly rises the left and right half arch units to the middle to be folded into a whole pair of arch units; carrying out prestress tension; and finally constructing the arch ring. According to the invention, no support is needed in the whole process, so that the safety risks of uneven settlement, support collapse and the like are eliminated, and the construction safety is greatly improved; the related cost of the bracket is saved, and the construction cost and the construction period are reduced; the structure is more optimized.)

1. The method for constructing the large-span cast-in-place concrete arch bridge without the support is characterized by comprising the following steps of: the method comprises the following steps:

constructing an arch support (1):

excavating an arch support foundation pit, pouring an arch support (1) in the arch support foundation pit, reserving an insertion hole (1A) and a prestress tensioning chamber (1B) on the arch support (1), wherein the insertion hole (1A) longitudinally penetrates through two ends of the arch support (1) along an arch bridge, and the prestress tensioning chamber (1B) is arranged at the bottom of the insertion hole (1A);

the arch center unit (2A) is manufactured:

the prefabricated concrete beam pieces (2B) are longitudinally assembled along the arch bridge to form a left half auxiliary arch unit (2A1) and a right half auxiliary arch unit (2A2) which are independent, and the tops of two adjacent concrete beam pieces (2B) are hinged;

the arch center unit (2A) is installed:

hydraulic telescopic arms (4) are respectively installed on the bridge abutments (3) at two ends of the arch bridge along the longitudinal direction of the arch bridge, and rollers (5) are hoisted at the outer ends of the hydraulic telescopic arms (4); reversely rolling the left half auxiliary arch unit (2A1) and the right half auxiliary arch unit (2A2) on the periphery of a roller (5) of the corresponding side hydraulic telescopic arm (4), and inserting the first section concrete beam piece (2B) of the left half auxiliary arch unit (2A1) and the right half auxiliary arch unit (2A2) into the insertion hole (1A) of the corresponding side; the hydraulic telescopic arm (4) extends longitudinally along the arch bridge to drive the roller (5) to rotate, so that the left half auxiliary arch unit (2A1) and the right half auxiliary arch unit (2A2) are naturally unloaded from the roller (5), are symmetrically and slowly lifted towards an arch crown by arch legs to be formed until the middle is closed, and connect the left half auxiliary arch unit (2A1) and the right half auxiliary arch unit (2A2) into a whole auxiliary arch unit (2A);

the arch center unit (2A) is installed and prestressed tensioning is carried out to form an arch center (2); and finally, constructing the arch ring (6).

2. The method for constructing a large-span cast-in-place concrete arch bridge without a bracket according to claim 1, wherein: two adjacent concrete beam pieces (2B) are hinged through round steel rivets (2C);

longitudinal prestressed holes (2B6) with two through ends are arranged on each concrete beam piece (2B) along the longitudinal direction of the arch bridge, and the longitudinal prestressed holes (2B6) of each concrete beam piece (2B) are sequentially spliced to form an arched longitudinal prestressed channel;

transverse prestressed holes (2B7) with two through ends are transversely arranged on each arch center unit (2A) along the arch bridge, and the transverse prestressed holes (2B7) of each arch center unit (2A) are sequentially spliced to form a transverse prestressed channel.

3. The method for constructing a large-span cast-in-place concrete arch bridge without a bracket according to claim 2, wherein: concrete beam piece (2B) is hollow box structure, including roof (2B1), diapire (2B2) and lateral wall (2B3) of both sides, is surrounded by roof (2B1), diapire (2B2) and lateral wall (2B3) of both sides and forms the cavity that both ends link up, is provided with strengthening rib (2B4) in the cavity.

4. The method for constructing a large-span cast-in-place concrete arch bridge without a bracket according to claim 3, wherein: and an engaging rib (2B5) is prefabricated on the top wall (2B1) of the concrete beam piece (2B).

5. The method for constructing a long-span cast-in-place concrete arch bridge without a bracket according to any one of claims 1 to 4, wherein: the roller (5) is a rubber roller.

6. The method for constructing a long-span cast-in-place concrete arch bridge without a bracket according to any one of claims 1 to 4, wherein: the specific operation of prestress tension is as follows: longitudinally tensioning each auxiliary arch unit (2A), transversely tensioning all the arch units (2A), and backfilling a prestress tensioning chamber (1B) with concrete;

during longitudinal tensioning, the steel strand penetrates through the longitudinal prestress channel to perform prestress tensioning, grouting is performed in the longitudinal prestress channel, and after the injected slurry reaches the designed strength, the anchor is sealed;

and during transverse tensioning, the steel strand penetrates through the transverse prestress channel to perform transverse prestress tensioning, grouting is performed in the transverse prestress channel, and the anchor is sealed after the injected slurry reaches the designed strength.

7. The method for constructing a long-span cast-in-place concrete arch bridge without a bracket according to any one of claims 1 to 4, wherein: after the prestress is tensioned and before the arch ring (6) is constructed, prepressing the arch centering (2); the pre-pressing load is 1.5 times of the dead load of the arch ring (6).

8. The method for constructing a long-span cast-in-place concrete arch bridge without a bracket according to any one of claims 1 to 4, wherein: the construction steps of the arch ring (6) are as follows:

firstly, installing a template;

then, along the radial direction of the arch bridge, dividing the arch ring (6) into multiple ring arch ring units (6A) and pouring sequentially from inside to outside; each ring arch ring unit (6A) is divided into an arch top section (6A1) positioned at the arch top, an arch foot section (6A2) positioned at the arch foot and an arch waist section (6A3) positioned between the arch top section (6A1) and the arch foot section (6A2) along the radial direction for pouring; when pouring, firstly pouring the arch foot sections (6A2) at two sides, then pouring the arch top section (6A1), and finally pouring the side arch waist section (6A 3); a spacing groove (6A4) is reserved between the arch springing section (6A2) and the arch top section (6A 1);

finally, pouring the spacing groove (6A4) to form a post-cast strip.

9. The method for constructing a long-span cast-in-place concrete arch bridge without a bracket according to claim 8, wherein: the method comprises the following steps that arch supports (7) are arranged on two sides of an arch frame (2) along the transverse direction of an arch bridge, a bottom template (8) is laid on the arch supports (7), the bottom template (8) and the top surface of the arch frame (2) form a bottom template, a side template and a top template are installed, and the bottom template, the side template and the top template surround to form an arch ring pouring cavity; and binding the arch ring reinforcing steel bars, and welding the arch ring reinforcing steel bars with the pre-embedded occlusion ribs (2B 5).

10. The method for constructing a long-span cast-in-place concrete arch bridge without a bracket according to any one of claims 1 to 4, wherein: establishing a finite element model of the arch center (2) according to a design drawing of the arch ring (6), simulating the construction process of the arch bridge, calculating the stress and displacement of the finite element model of the arch center (2), adjusting the finite element model of the arch center (2) according to the simulation calculation structure, and obtaining a model of each concrete beam piece (2B); and finally, manufacturing the concrete beam piece (2B) according to the model of the concrete beam piece (2B).

Technical Field

The invention belongs to the field of bridge engineering, and particularly relates to a support-free construction method of a large-span cast-in-place concrete arch bridge.

Background

The arch bridge arch ring is the structure that is mainly used bearing pressure, and an important advantage of reinforced concrete arch bridge is compressive strength that can full play concrete material to make its bearing capacity be greater than general reinforced concrete beam type bridge structures, and reinforced concrete arch bridge has a great deal of advantages such as durability is good, the maintenance cost is lower and the simple structure. In addition, modern bridge design more and more attaches importance to bridge aesthetics, the nature has no standard straight line, reinforced concrete arch bridge is favored by the characteristics of beautiful appearance and easy decoration, and especially reinforced concrete arch bridge with rich rhythmic modeling in scenic spots can always have aesthetic effect coordinated with natural environment. Therefore, the ancient bridge type of arch bridge is also increasingly emphasized by the recent bridge construction. However, reinforced concrete arch bridges constructed in urban roads and canyon scenic spots are mainly constructed in a large-span cast-in-place mode with the single-hole span of more than or equal to 40 m. At present, the bridge is usually constructed by adopting a floor stand method, but the method has the following defects:

firstly, a floor support needs to be erected in advance, the construction period is prolonged, the construction efficiency is influenced, and the related cost of the floor support is increased;

secondly, unsafe factors such as uneven settlement, collapse and the like exist in the floor stand, so that the line shape of the cast-in-place arch ring is changed, and even more serious safety accidents are caused.

Disclosure of Invention

The invention aims to solve the problems of high construction cost, long construction period, low safety and the like of a cast-in-place reinforced concrete arch bridge, and provides a support-free construction method of a large-span cast-in-place concrete arch bridge, so that the safety and the economy of construction are guaranteed.

The technical scheme adopted by the invention is as follows: the method for constructing the large-span cast-in-place concrete arch bridge without the support comprises the following steps:

and (3) arch support construction:

excavating an arch support foundation pit, pouring an arch support in the arch support foundation pit, reserving an insertion hole and a prestress tensioning chamber on the arch support, wherein the insertion hole longitudinally penetrates through two ends of the arch support along an arch bridge, and the prestress tensioning chamber is arranged at the bottom of the insertion hole;

manufacturing an arch frame unit:

assembling the prefabricated concrete beam pieces longitudinally along the arch bridge to form a left half auxiliary arch frame unit and a right half auxiliary arch frame unit which are independent, wherein the tops of two adjacent concrete beam pieces are hinged;

installing an arch frame unit:

hydraulic telescopic arms are respectively arranged on the abutment at the two ends of the arch bridge along the longitudinal direction of the arch bridge, and rollers are hoisted at the outer ends of the hydraulic telescopic arms; reversely rolling the left and right semi-auxiliary arch frame units on the periphery of the roller of the corresponding side hydraulic telescopic arm, and inserting first sections of concrete beam pieces of the left and right semi-auxiliary arch frame units into the inserting holes on the corresponding sides; the hydraulic telescopic arm extends longitudinally along the arch bridge to drive the roller to rotate so as to naturally unload the left half auxiliary arch frame unit and the right half auxiliary arch frame unit from the roller, the left half auxiliary arch frame unit and the right half auxiliary arch frame unit are symmetrically and slowly lifted to the arch crown from arch feet and are folded to the middle, and the left half auxiliary arch frame unit and the right half auxiliary arch frame unit are connected into a whole auxiliary arch frame unit in the middle;

carrying out prestress tensioning after all the arch center units are installed, grouting and sealing anchors, and backfilling a tensioning chamber to form an arch center; and finally, constructing the arch ring.

Furthermore, two adjacent concrete beam pieces are riveted and hinged through round steel;

longitudinal prestressed holes with two through ends are longitudinally arranged on each concrete beam piece along the arch bridge, and the longitudinal prestressed holes of each concrete beam piece are sequentially spliced to form an arched longitudinal prestressed channel;

transverse prestressed holes with two through ends are transversely arranged on each arch center unit along the arch bridge, and the transverse prestressed holes of each arch center unit are sequentially spliced to form a transverse prestressed channel.

Further, the concrete beam piece is hollow box structure, including the lateral wall of roof, diapire and both sides, surrounds the cavity that forms both ends and link up by the lateral wall of roof, diapire and both sides, is provided with the strengthening rib in the cavity.

Furthermore, the top wall of the concrete beam piece is prefabricated with an occlusion rib.

Further, the roller is a rubber roller.

Further, the specific operation of the prestress tension is as follows: firstly, longitudinally tensioning each auxiliary arch frame unit, transversely tensioning all the arch frame units, and backfilling a prestress tensioning chamber with concrete;

during longitudinal tensioning, the steel strand penetrates through the longitudinal prestress channel to perform prestress tensioning, grouting is performed in the longitudinal prestress channel, and after the injected slurry reaches the designed strength, the anchor is sealed;

and during transverse tensioning, the steel strand penetrates through the transverse prestress channel to perform transverse prestress tensioning, grouting is performed in the transverse prestress channel, and the anchor is sealed after the injected slurry reaches the designed strength.

Further, after prestress tensioning and before arch ring construction, pre-pressing the arch frame; the pre-pressing load is 1.5 times of the dead load of the arch ring.

The further arch ring construction steps are as follows:

firstly, installing a template; then, along the radial direction of the arch bridge, dividing the arch ring into multiple ring arch ring units, and pouring sequentially from inside to outside; each ring arch ring unit is divided into an arch top section positioned at an arch top, an arch foot section positioned at an arch foot and an arch waist section positioned between the arch top section and the arch foot section along the radial direction for pouring; when pouring, firstly pouring the arch foot sections at two sides, then pouring the arch top section, and finally pouring the side arch waist section; and a spacing groove is reserved between the arch springing section and the arch topping section; and finally, forming a post-cast strip by the casting spacing groove.

Furthermore, along the transverse direction of the arch bridge, arch supports are arranged on two sides of the arch center, a bottom template is laid on the arch supports, the bottom template and the top surface of the arch center form a bottom template, a side template and a top template are installed, and the bottom template, the side template and the top template surround to form an arch ring pouring cavity; and binding the arch ring reinforcing steel bars, and welding the arch ring reinforcing steel bars with the pre-embedded occlusion ribs.

Further, establishing a finite element model of the arch according to an arch ring design drawing, simulating the construction process of the arch bridge to calculate the stress and displacement of the finite element model of the arch, adjusting the finite element model of the arch according to the simulated calculation structure, and obtaining a model of each concrete beam piece; and finally, manufacturing the concrete beam piece according to the model of the concrete beam piece.

The invention has the beneficial effects that: the invention discloses a method for constructing a large-span cast-in-place concrete arch bridge without a support, which adopts the following advantages that a first section of concrete beam piece of an arch frame unit is inserted into an insertion hole at the corresponding side, is supported by an arch center, and is stretched by a hydraulic telescopic arm to drive a left half auxiliary arch frame unit and a right half auxiliary arch frame unit to be naturally laid, so that the construction without the support of the arch frame is realized, compared with the traditional support construction, the method has the following advantages:

firstly, the support is not needed in the whole construction process, so that the safety risks of uneven settlement, support collapse and the like are eliminated, and the construction safety is greatly improved;

secondly, the construction of the bracket is avoided, so that the related cost of the bracket and the construction period of the bracket are saved, and the construction cost and the construction period are greatly reduced;

thirdly, the arch center is formed by assembling concrete beam pieces, the concrete beam pieces can be prefabricated in advance, the construction period can be further shortened, and each concrete beam piece can be correspondingly produced according to the stress of each position of the arch center, so that the structure is optimized;

and fourthly, when the arch centering is installed, the hydraulic telescopic arm is matched with the arch centering, the investment of mechanical equipment is less, the construction is safer, the cost is lower, and the operation is simpler.

Drawings

FIG. 1 is a schematic representation of the present invention after construction of the arch and arch ring;

FIG. 2 is a top view of the arch;

FIG. 3 is a schematic view of the assembled arch and abutment;

FIG. 4 is a schematic structural view of a concrete beam;

FIG. 5 is a schematic view of an arch unit installation;

FIG. 6 is a schematic view of arch ring casting;

fig. 7 is a schematic view of arch ring pouring formwork erection.

In the figure, an arch support 1, an inserting hole 1A, a prestress tensioning chamber 1B, an arch frame 2, an arch frame unit 2A, a left half auxiliary arch frame unit 2A1, a right half auxiliary arch frame unit 2A2, a concrete beam piece 2B, a top wall 2B1, a bottom wall 2B2, a side wall 2B3, a reinforcing rib 2B4, an engagement rib 2B5, a longitudinal prestress hole 2B6, a transverse prestress hole 2B7, a round steel rivet 2C, a bridge abutment 3, a hydraulic telescopic arm 4, a roller 5, an arch ring 6, an arch ring unit 6A, an arch top section 6A1, an arch foot section 6A2, an arch waist section 6A3, a spacing groove 6A4, an arch support 7 and a bottom template 8.

Detailed Description

The invention is further described below with reference to the following figures and examples:

the method for constructing the large-span cast-in-place concrete arch bridge without the support comprises the following steps:

constructing an arch support 1:

excavating an arch support foundation pit, pouring an arch support 1 in the arch support foundation pit, reserving an insertion hole 1A and a prestress tensioning chamber 1B on the arch support 1, wherein the insertion hole 1A longitudinally penetrates through two ends of the arch support 1 along an arch bridge, and the prestress tensioning chamber 1B is arranged at the bottom of the insertion hole 1A;

the arch center unit 2A is manufactured:

assembling the prefabricated concrete beam pieces 2B along the longitudinal direction of the arch bridge to form a left half auxiliary arch frame unit 2A1 and a right half auxiliary arch frame unit 2A2 which are independent, wherein the tops of two adjacent concrete beam pieces 2B are hinged;

the arch unit 2A is installed:

hydraulic telescopic arms 4 are respectively arranged on the abutment 3 at two ends of the arch bridge along the longitudinal direction of the arch bridge, and rollers 5 are hoisted at the outer ends of the hydraulic telescopic arms 4; reversely rolling the left sub-arch truss unit 2A1 and the right sub-arch truss unit 2A2 on the periphery of the roller 5 of the hydraulic telescopic arm 4 at the corresponding side, and inserting the first section of concrete beam piece 2B of the left sub-arch truss unit 2A1 and the right sub-arch truss unit 2A2 into the inserting hole 1A at the corresponding side; the hydraulic telescopic arm 4 extends longitudinally along the arch bridge to drive the roller 5 to rotate, so that the left half auxiliary arch frame unit 2A1 and the right half auxiliary arch frame unit 2A2 are naturally unloaded from the roller 5, are symmetrically and slowly lifted to a vault from an arch foot to be formed, are folded to the middle, and connect the left half auxiliary arch frame unit 2A1 and the right half auxiliary arch frame unit 2A2 into a whole auxiliary arch frame unit 2A in the middle;

after all the arch frame units 2A are installed, prestress tensioning is carried out, grouting and anchor sealing are carried out, and a tensioning chamber is backfilled to form an arch frame 2; finally, the arch ring 6 is constructed.

According to the invention, when the arch support 1 is constructed, after an arch support foundation pit is excavated, a formwork is supported and a splicing hole 1A and a prestress tensioning chamber 1B are reserved, concrete is poured in layers after the arch support 1 is bound by reinforcing steel bars, and the formwork can be removed and water is sprayed for maintenance when the strength of the concrete reaches more than 2.5 MPa. The inserting hole 1A is used for inserting the arch springing of the arch centering 2, so that the arch centering 1 and the arch centering 2 are fixedly embedded together to form good support for the arch centering 2. The prestressed tensioning chamber 1B provides an operation space for the prestressed tensioning jack.

The left sub-arch unit 2a1 and the right sub-arch unit 2a2 formed by assembling the concrete beam pieces 2B in the longitudinal direction of the arch bridge have the following advantages: one of them, the precast concrete beam piece 2B is easier, and can carry out the preparation of each concrete beam piece 2B according to the weak position of atress and safe position actual conditions, and adaptability is better, and the structure is more optimized, when guaranteeing the atress performance, effective material saving to alleviate 2 whole weights of bow member. And the left half auxiliary arch frame unit 2A1 and the right half auxiliary arch frame unit 2A2 are independently hoisted, so that hoisting is easier, the requirement on hoisting equipment is lower, and hoisting cost is saved by 4. The tops of two adjacent concrete beam pieces 2B are hinged, namely after the concrete beam pieces 2B are assembled into an arch, the hinged points are closer to the periphery of the concrete beam pieces 2B, so that the arch center units formed by assembling the concrete beam pieces 2B can be reversely rotated into a roll, namely, the top wall 2B1 of the concrete beam piece 2B is rolled up at the inner side and the bottom wall 2B2 of the concrete beam piece 2B is rolled up at the outer side; when the concrete beam pieces 2B are rotated in the forward direction, the side walls 2B3 of the adjacent concrete beam pieces 2B abut against each other and limit each other to form an arch.

The left sub-arch unit 2a1 is rewound on the drum 5 of the left hydraulic telescopic arm 4. The reverse rolling means rolling from the last concrete beam piece 2B of the left half sub-arch unit 2a1, and the top wall 2B1 of the concrete beam piece 2B is on the inner side and the bottom wall 2B2 is on the outer side in the radial direction of the drum 5. After the rolling is finished, the first section of concrete beam piece 2B of the left half auxiliary arch truss unit 2A1 is used as a traction end and is inserted into the insertion hole 1A of the left arch support 1. In this process, the hydraulic telescopic arm 4 is in a retracted state. When the first section of concrete beam piece 2B of the left half auxiliary arch unit 2A1 is positioned, the hydraulic telescopic arm 4 slowly extends to the middle of the arch bridge along the longitudinal direction of the arch bridge to drive the roller 5 to rotate, and the left half auxiliary arch unit 2A1 naturally falls off from the roller 5 and rotates around the hinged point to form an arch. The installation of the right sub-arch unit 2a2 is also possible. Until the middle of the left half auxiliary arch frame unit 2A1 and the right half auxiliary arch frame unit 2A2 is folded, the left half auxiliary arch frame unit 2A1 and the right half auxiliary arch frame unit 2A2 are lifted from the lower chord surface of the left half auxiliary arch frame unit 2A1 and the right half auxiliary arch frame unit 2A2 by using the hydraulic telescopic arm 4, so that the left half auxiliary arch frame unit 2A1 and the right half auxiliary arch frame unit 2A2 are accurately inserted into the upper chord surface and riveted, and movable steel rivets and other connecting pieces are inserted to realize the integral folding.

In order to realize splicing of the concrete beam pieces 2B, as shown in fig. 1 and 3, two adjacent concrete beam pieces 2B are hinged through round steel rivets 2C; the round steel rivets 2C and passes and reserves the connecting hole on upper portion when concrete beam piece 2B makes and is connected two concrete beam pieces 2B promptly, forms the structure of similar hinge, and concrete beam piece 2B can rivet 2C around the round steel and rotate.

Longitudinal prestressed holes 2B6 with two through ends are longitudinally arranged on each concrete beam piece 2B along the arch bridge, and the longitudinal prestressed holes 2B6 of each concrete beam piece 2B are sequentially spliced to form an arched longitudinal prestressed channel;

transverse prestressed holes 2B7 with two ends communicated are transversely arranged on each arch center unit 2A along the arch bridge, and the transverse prestressed holes 2B7 of each arch center unit 2A are sequentially spliced to form a transverse prestressed channel.

In order to make the arch bridge structure lighter and lighter, and lighter in self weight, preferably, as shown in fig. 4, the concrete beam 2B is a hollow box structure, and includes a top wall 2B1, a bottom wall 2B2 and side walls 2B3 on both sides, a cavity with both ends penetrating is formed by the top wall 2B1, the bottom wall 2B2 and the side walls 2B3 on both sides, and reinforcing ribs 2B4 are arranged in the cavity.

In order to facilitate welding with the steel bars of the arch ring 6 and to integrally embed the arch frame 2 and the arch ring 6, the top wall 2B1 of the concrete beam piece 2B is prefabricated with an engaging rib 2B 5.

The roller 5 may be a steel roller, but it is preferable that the roller 5 is a rubber roller in order to avoid a problem that the concrete beam piece 2B is easily broken by collision with the concrete beam piece 2B.

In order to test the stress of the arch frame 2 and the stability of the structure thereof and reduce the inelastic deformation so as to ensure the construction safety of the cast-in-place arch ring 6, and adjust the pre-arch degree, after the pre-stress is tensioned and before the construction of the arch ring 6, the arch frame 2 is pre-pressed; the pre-pressing load is 1.5 times of the dead load of the arch ring 6. And (4) pre-pressing by using a water bag, and unloading when the pre-pressing period is not less than 10 days and the settlement observation is not more than 1mm for two consecutive days.

Preferably, the construction steps of the arch ring 6 are as follows:

firstly, installing a template; then, along the radial direction of the arch bridge, dividing the arch ring 6 into multiple ring arch ring units 6A, and pouring sequentially from inside to outside; each ring arch ring unit 6A is divided into an arch top section 6A1 positioned at the arch top, an arch foot section 6A2 positioned at the arch foot and an arch waist section 6A3 positioned between the arch top section 6A1 and the arch foot section 6A2 along the radial direction for casting; when pouring, firstly pouring the arch foot sections 6A2 on the two sides, then pouring the arch top section 6A1, and finally pouring the side arch waist section 6A 3; a spacing groove 6A4 is reserved between the arch springing section 6A2 and the arch top section 6A 1; finally, the spacing groove 6A4 is poured to form a post-cast strip. The arch ring 6 layered and segmented pouring mode disclosed by the invention reduces the collapse risk caused by overlarge pressure on the arch frame 2 in the pouring process of the arch ring 6, and accords with the protection principle of the weak point of the arch frame.

In order to meet the requirement of bridge width, as shown in fig. 7, arch supports 7 are arranged on two sides of an arch frame 2 along the transverse direction of the arch bridge, a bottom formwork 8 is laid on the arch supports 7, and the bottom formwork 8 and the top surface of the arch frame 2 form a bottom formwork. The arch frame 2 is used as a part of the bottom die and is widened to the designed bridge width through the arch support 7, so that the rigidity of the bottom die is good, and the installation period of the bottom die is short. The gap between the bottom template 8 and the arch center 2 is filled with the processed wood strips, and then the water-stopping adhesive tape is used for jointing to prevent slurry leakage. After the bottom die is installed, measuring and setting a center line, a side line and an elevation, marking the positions of each section point and the diaphragm plate, installing an arch ring side die and a top die, binding arch ring reinforcing steel bars, welding the arch ring reinforcing steel bars with pre-embedded occlusion ribs 2B5, and forming an arch ring pouring cavity by surrounding the bottom die, the side die and the top die. The formworks adopted for pouring the arch ring 6 are all wood formworks, so that the weight is light and the cost is low.

In order to obtain a more reasonable arch center 2, the concrete beam piece 2B of the arch center 2 is obtained through modeling and checking calculation, and the concrete operation is as follows: and establishing a finite element model of the arch center 2 according to the design drawing of the arch ring 6. During modeling, the selection of a structural calculation model, materials, a calculation section, boundary conditions and the like is consistent with the actual engineering. The structure calculation diagram can reflect the bearing capacity condition under each working condition and the structure forming process. During simulation calculation, the dead load, the template for pouring the arch ring, the load of the steel bar and the concrete are mainly considered, and the concrete load is the dead load of the arch ring. The dead weight of the structure is automatically calculated by combining the volume of the structure through the characteristics (volume weight) given to the material in the model; the arch ring constant load is considered by applying uniformly distributed beam unit loads in the model; and correspondingly considering other construction loads in the construction process according to actual conditions. The stress distribution diagram and the displacement distribution diagram of the model arch centering are obtained through modeling calculation analysis in the arch ring construction process, the safe part, the transition part and the weak part of the arch centering can be accurately obtained, and the weak part can be adjusted through presetting the camber or increasing the stress area to obtain the model of each concrete beam piece 2B; and finally, manufacturing the concrete beam piece 2B according to the model of the concrete beam piece 2B.