CN113430945B

CN113430945B - Design method of assembly type bracket, bracket and construction method of bridge 0# block

Info

Publication number: CN113430945B
Application number: CN202110751003.9A
Authority: CN
Inventors: 魏华; 韩玉; 梁厚燃; 解威威; 叶志权; 董宏源; 马文安; 王振琦
Original assignee: Guangxi Road and Bridge Engineering Group Co Ltd
Current assignee: Guangxi Road and Bridge Engineering Group Co Ltd
Priority date: 2021-07-01
Filing date: 2021-07-01
Publication date: 2022-08-26
Anticipated expiration: 2041-07-01
Also published as: CN113430945A

Abstract

The invention relates to the field of bridge construction, in particular to a design method of an assembled bracket, a bracket and a construction method of a bridge 0# block, wherein the design method is characterized in that the construction condition of the bridge 0# block is summarized and counted based on a large amount of data, the external load range of the bracket is firstly calculated by summarizing the size of the 0# block according to the limit value and the bridge span classification, then the load and internal force change rule of each rod piece of the bracket is deeply analyzed through the transmission path of the external load on the bracket, and the bracket structure is optimized, so that the method is economical, reasonable and feasible in technology; by the design method, the designed bracket structure can be reversely applied to the bridge in the design range, and the application proportion of the bracket structure to the existing bridge is high.

Description

Design method of assembly type bracket, bracket and construction method of bridge 0# block

Technical Field

The invention relates to the technical field of bridge engineering construction, in particular to a design method of an assembled bracket, a bracket and a construction method of a bridge 0# block.

Background

With the demand of economic development in China, the number of large-span and high-rise bridges spanning rivers, seas, lakes and deep-mountain canyons is more and more, and continuous beam bridges and continuous rigid frame bridges are the main bridge types to be selected due to high rigidity and strong spanning capability. In recent years, continuous beam bridges and continuous rigid frame bridges in China are mainly constructed by adopting a cantilever casting construction method, and the construction method is necessarily accompanied by a large number of 0# blocks (also called 0# blocks) for construction.

In the traditional method, when a 0# block at the top end of a pier body is cast, methods such as erecting full framing, steel pipe pile frames and the like are mainly adopted; and when the strength of the 0# block reaches a specified value, the 0# block is taken as an operation platform, and equipment such as construction machinery, a hanging basket and the like is installed on the operation platform to carry out symmetrical pouring or assembling of the No. 1 block, the No. 2 block and the like. However, these methods have great limitations, mainly embodied in low stability, poor economy and high safety risk, and are generally only suitable for bridge construction with good terrain conditions, small bridge span and low buttresses. The triangular bracket is suitable for casting construction of a 0# block of a bridge with large span and high buttresses under complex geological conditions such as rivers, lakes, deep mountains and canyons, and the like. The triangular bracket is usually formed by connecting rod pieces such as a horizontal rod, a vertical rod, an oblique rod and the like into a plurality of tripods, and then connecting the plurality of tripods with embedded parts embedded in a pier body to form a structural support system; the triangular bracket has the characteristics of simple structure, definite stress, convenient construction and the like, and has good application prospect.

Currently, the triangular bracket mainly comprises a welding mode and an assembling mode. The welding type triangular bracket is mainly used in a connection mode due to high safety performance; however, this connection method has a series of problems: firstly, the overhead operation of bracket welding has high risk, long time and difficult quality guarantee, and is greatly influenced by external environment; secondly, the triangular brackets are welded through embedded parts, so that the pier body is greatly influenced, and a great potential safety hazard is caused; finally, the triangular bracket installed by welding has extremely low turnover utilization rate, is difficult to disassemble and assemble, has poor economy and is not beneficial to sustainable development.

Although the assembly type triangular bracket has the characteristics of quick construction, low risk and turnover (only the construction of 0# piece of the same bridge is limited), the problems of the welding type triangular bracket can be solved, the traditional welding type triangular bracket cannot be greatly replaced, the main reason is that the current assembly type bracket is only designed and used for a specific bridge, namely, the design concept of 'one bridge and one bracket' is followed, so that the brackets used for different bridge constructions need to be repeatedly customized and reviewed, the technical problems of high design cost, long construction period and poor bracket universality are caused, and meanwhile, the structural safety performance of the assembly type bracket applied under different scenes is difficult to guarantee, and the reutilization cannot be really realized.

Disclosure of Invention

The invention aims to: aiming at the problems that in the prior art, the assembly type bracket is designed and used only for a specific bridge and follows the design concept of 'one bridge and one bracket', the brackets used in different bridge constructions need to be repeatedly designed and reviewed, and the design cost is high, the construction period is long, and the bracket universality is poor, the design method of the assembly type bracket, the bracket and the construction method of the bridge 0# block are provided, so that the structural safety of the assembly type bracket can generally adapt to the bridge construction requirement, the use universality of the bracket is improved, the design cost is reduced, and the construction efficiency is improved.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method of designing a fabricated bracket, comprising the steps of:

the method comprises the steps of firstly, counting cantilever pouring bridge construction data parameters and establishing a database, wherein the data parameters comprise 0# block construction size, arrangement interval of bracket members and an angle theta;

classifying the construction size of the 0# block according to the span of the bridge to obtain a size limit value, respectively corresponding to the areas of the web plate section, the top and bottom plate section and the flange plate section, and calculating to obtain a concrete load q of the 0# block ₂ Range, thereby obtaining a design face load q range, i.e., a bracket external load range, where the design face load q includes a formwork support load q ₁ Concrete load q ₂ And a load q of a manual machine ₃ And a vibrating load q ₄ ；

Selecting a bracket structure form, analyzing a bracket load distribution rule according to an external load transmission path of the bracket, and converting the design surface load q into a design line load q' to obtain the internal force design value range of each rod piece of the bracket; according to the internal force configuration of the bracket, the bracket rod piece arrangement is obtained;

designing a bracket and rechecking the strength, the rigidity and the stability; the size of the bracket is designed based on the number of two bracket supports, the length of a main longitudinal beam of the bracket is 2-3.5 m, and the distance a from the hinged center position of an inclined strut of the bracket and the main longitudinal beam to the free end position of the main longitudinal beam is not more than 1 m. The free end of the main longitudinal beam is the end of the main longitudinal beam far away from the construction pier stud.

The construction condition of the 0# block of the bridge is summarized and counted based on a large amount of data, the external load range of the bracket is firstly calculated by summarizing the size of the 0# block according to the limit value and the bridge span classification, then the load and internal force change rule of each rod piece of the bracket is deeply analyzed through the transmission path of the external load on the bracket, and the bracket structure is optimized, so that the method is economical, reasonable and feasible in technology; by the design method, the designed size parameters of the bracket member can be applied to the construction requirements of external loads of bridges in a design range, and the application proportion of the bracket member to the existing bridges is high. The bracket with the main longitudinal beam with the length of 2 m-3.5m and the reasonable position of the hinge pivot can be suitable for the construction of a 0# block on a double-limb pier bridge with the span of within 200m, the cantilever length of within 3m and the pier column clear distance of 5m-6m and a single-limb pier bridge with the span of within 150m and the cantilever length of within 3.5m, and the bracket component can meet the external load requirement of the bridge and has controllable flexural deformation.

Compared with the traditional bracket, the bracket structure obtained by the design method of the assembly type bracket provided by the invention has good universality, fundamentally solves the problem that the traditional bracket is only applied to a specific bridge, avoids the complex links of repeated customized design, review, change and the like of the brackets used for different bridge constructions, saves the design flow and design cost, shortens the construction period, has more humanized whole application process, can be suitable for the rapid design of different brackets required for different bridge constructions, and has high universality.

Preferably, in step one, a database of data parameters for a span cast-in-place bridge construction of less than 200m is established.

Preferably, in the second step, the design surface load q is calculated in a mode of simulating layered pouring and simplifying chamfering, wherein the concrete loads corresponding to the position areas of the web plate section, the top and bottom plate sections and the flange plate section are respectively calculated according to the following formulas and the limit value of the concrete load is obtained:

web sections: q. q.s ₂₁ ＝(H ₁ +0.5H ₂ )γ；

Wherein H ₁ Represents the first layer casting height of 0# block, H ₂ Representing the casting height of the second layer of the 0# block, and gamma represents the volume weight of the 0# reinforced concrete; the coefficient of 0.5 represents the load of the web plate segment transmission bracket structure during the second layer pouringA load reduction factor;

top and bottom plate sections: q. q.s ₂₂ ＝1.15(0.5D ₁ +D ₂ )γ；

Wherein D ₁ Indicates the thickness of the roof board D ₂ The thickness of the bottom plate is shown, the coefficient is 1.15, the influence of chamfer concrete at the junction of the top bottom plate and the web plate is considered, and the coefficient is 0.5, the load reduction coefficient of the top plate transferred to the bracket structure during the second pouring is obtained;

thirdly, flange plate section: q. q of ₂₃ ＝D ₄₅ ×γ；

Wherein D ₄₅ Indicating the average thickness of the flange plate.

The design load is calculated according to the simplified modes of layered pouring and chamfering, so that the actual stress condition of the bracket can be closer to, the stress analysis is reasonable, and the material waste is greatly reduced; and the calculation process can be simplified, the design time is shortened, and the construction efficiency is improved.

Preferably, in step three, acquiring a design line load range on the longitudinal distribution beam according to the external face load, obtaining an internal force design range of the longitudinal distribution beam, and calculating according to the following formula:

designing a line load q' ═ qxx;

the maximum shearing force Q is β × Q' y;

maximum bending moment M ═ α × q' y ² ；

In the formula, x represents the distance between the longitudinal distribution beams, alpha represents a bending moment coefficient, beta represents a shear coefficient, and y represents the distance between the transverse distribution beams;

and obtaining a longitudinal distribution beam arrangement scheme according to the internal force configuration of the longitudinal distribution beam.

Preferably, in the third step, obtaining a design line load range on the transverse distribution beam according to the external face load to obtain an internal force design range of the transverse distribution beam, and calculating according to the following formula:

designing a line load q' ═ qxy;

support reaction force R:

R＝R _A ＝R _B ；

R＝q′ ₁₀ l ₁ +q′ ₂₀ l ₂ +q′ ₃₀ l ₃ ；

a support shear force Q:

+Q＝1/2q′ ₁₀ l ₁ +q′ ₃₀ l ₃ ；

-Q＝+Q-R；

support bending moment M _{Support base} And midspan bending moment M _Midspan ：

Wherein y represents the transverse distribution beam spacing, R _A Representing the reaction force of the abutment at point A, R _B Representing the abutment reaction force, q 'at point B' ₁₀ Representing the corresponding web segment line load, q 'on the transverse distribution beam' ₂₀ Representing the corresponding roof and floor segment line loads, q ', on the transverse distribution beam' ₃₀ Representing the line load of the corresponding flange plate section on the transverse distribution beam;

l ₁ ＝D ₃ ，D ₃ the thickness of the web; l. the ₂ ＝1/2B ₂ -D ₃ ，B ₂ The box chamber is wide; l ₃ ＝B ₃ ，B ₃ The width of the flange plate is wide;

and obtaining a transverse distribution beam arrangement scheme according to the internal force configuration of the transverse distribution beam.

Preferably, in the third step, the design line load range on a single bracket rack is obtained according to the external face load, and the design internal force ranges of the main longitudinal beam and the inclined strut are respectively obtained; and obtaining an arrangement scheme of the main longitudinal beam and the inclined strut according to the internal force configuration.

The invention provides an assembled bracket, which comprises at least two bracket supports, wherein each bracket comprises a main longitudinal beam and an inclined strut, the main longitudinal beam comprises a fixed section and an adjusting section, the fixed section is detachably connected with the adjusting section so that the adjusting section is fixedly connected with the fixed section into a whole, one end of the fixed section is hinged with a first anchoring member, the first anchoring member is used for connecting a pier stud, the other end of the fixed section is hinged with one end of the inclined strut, the other end of the inclined strut is hinged with a second anchoring member, and the second anchoring member is used for connecting the pier stud; the length of the fixed section is 2 m-3 m, and the distance between the central position of the inclined strut hinged with the fixed section and the free end position of the main longitudinal beam is not more than 1 m.

The free end of the main longitudinal beam refers to the end part of the main longitudinal beam, which is hinged with the end of the first anchoring member, and when the adjusting section is not required to be installed in construction, the free end of the main longitudinal beam refers to the end part of the fixing section which can be connected with the adjusting section; when the adjusting section is installed in construction, the free end of the main longitudinal beam points to the outermost side of the adjusting section.

The assembled bracket provided by the invention utilizes a sectional bracket structure to divide a main longitudinal beam into a fixed section and an adjusting section, the end part of the fixed section is hinged with an inclined strut, and the adjusting section is detachably connected with the fixed section; while defining a fixed segment length of 2-3 m. The adoption of the separated structure design considers the construction environment of the double-limb pier cantilever bridge with the span of 200m below at present: the net distance between the pier columns is generally 5m-6 m; when setting up the bracket in two buttress inboards and being relative setting, adopt the main longitudinal beam that is less than 1/2 pier stud net apart from length to be under construction, two brackets can not take place to interfere and the centre can reserve enough construction space and avoid dieing, and structural arrangement is reasonable, construction convenience is nimble. When the single-limb pier bridge 0# block with the maximum cantilever length of 3.5m is used for construction, the length of the main longitudinal beam can reach 3.5m to adapt to the construction of the maximum cantilever length by flexibly replacing the length of the adjusting section under the size of a prefabricated bracket suitable for the construction of the double-limb pier, and the single-limb pier bridge 0# block is not required to be customized one by one again according to the actual working condition. The length (basically, the adjusting section) exceeding the hinge pivot is limited to be less than or equal to 1m based on the fixed section with the length of 2-3m, so that the bearing requirement of the cantilever length of the span bridge in a design range on the bracket can be met, the construction safety of the bracket structure is ensured, the length of the main longitudinal beam and the position of the hinge pivot can adapt to the external load of the bridge, and the deflection deformation is controllable.

The assembly type bracket provided by the invention can be suitable for construction of a double-limb pier bridge with the span of within 200m, the cantilever length of within 3m and the pier column clear distance of 5m-6m and a 0# block on a single-limb pier bridge with the span of within 150m and the cantilever length of within 3.5m, has strong adaptability to construction working conditions, good universality, high standard customization degree and low cost, is beneficial to popularization, solves the problem that the traditional bracket only aims at a single point of specific bridge application, omits complicated links such as repeated customization design, review and change of brackets used for different bridge constructions, saves the cost, shortens the construction period and is flexible in construction.

Preferably, the assembled bracket provided by the invention further comprises a plurality of transverse distribution beams, the plurality of transverse distribution beams are detachably connected to all the main longitudinal beams, and the distance between every two adjacent transverse distribution beams is not more than 0.7 m.

Preferably, when the bridge span is less than 150m, the distance between two adjacent transverse distribution beams is not more than 0.7 m; when the bridge span is more than or equal to 150m and less than 200m, the distance between two adjacent transverse distribution beams is not more than 0.6 m. And reasonable transverse distribution beam spacing arrangement is selected, so that the stress and the economy are balanced. If the distance between the transverse distribution beams is too large, the transverse distribution beams are easy to generate flexural deformation; if the distance is too small, material waste is caused, and the cost is increased.

Preferably, the assembly type bracket provided by the invention further comprises a cross-link, wherein a plurality of continuous positioning holes are formed in the cross-link; all the inclined struts are connected through one transverse connection, and/or all the main longitudinal beams are connected through one transverse connection. Two adjacent bracket supports are fixedly connected by using a transverse connection to form a whole, so that the stability and the integrity of the bracket are improved; the transverse connection also has universality, and the fixed position can be adjusted according to the working conditions of different bridge 0# blocks to adapt to construction.

Preferably, the installation included angle theta between the inclined strut and the main longitudinal beam is 45-60 degrees.

Preferably, the mounting included angle is 60 °. According to the fixed mounting included angle, the length of the fixed section of the prefabricated main longitudinal beam and the length of the inclined strut are fixed, the bracket structure is standardized while the structural stress safety is guaranteed, and the bracket is suitable for construction of a 0# block of a bridge within a design range, so that the universality of the bracket is improved. Wherein, the adjustment section can be prefabricated into multiple length in order to adapt to operating condition.

Preferably, the end face of the fixing section is connected with the end face of the adjusting section through a bolt.

Preferably, the bracket is provided with two bracket frames, two the bracket frames are used for being installed in the corresponding position department in single case roof beam 0# piece both sides web center respectively, and material saving when guaranteeing structure atress safety has simplified the structure and has also reduced the cost.

Preferably, the bracket rack is provided with two specifications, the first specification is as follows: the length of the fixing section is 2420mm, and the length of the inclined strut is 4340 mm; the second specification is: the length of the fixed section is 2920mm, and the length of the inclined strut is 5340 mm. When the bracket is used for constructing the double-limb pier, the bracket with the first specification is used along the longitudinal bridge direction; when the bracket is used for single-limb pier construction, the bracket with the second specification is used in the longitudinal bridge direction, and the bracket with the first specification is used in the transverse bridge direction, so that the stress is more reasonable, and the material utilization rate is high; the bracket is customized according to actual working conditions, and the adjusting sections with various lengths are prefabricated for adjustment and replacement, so that the bracket can be suitable for the construction of casting the 0# block of the bridge by using each cantilever with the span within 200m and the cantilever length within 3.5 m.

Preferably, the second anchor member and the first anchor member are of the same construction, the first anchor member being longer than the second anchor member.

Preferably, be equipped with two steel sheets and preformed hole on the first anchor component, the steel sheet is used for vertical grafting on the pier stud of being under construction, the preformed hole is located two the steel sheet middle part, the preformed hole is used for the anchor to connect the counter-pull steel strand wires, and the pull resistance of steel strand wires is better.

Preferably, the cross-sectional shape of the steel plate is rectangular or i-shaped. The steel plate with the I-shaped cross section is preferably selected, so that the contact area of the steel plate and the pier column concrete can be increased, and the local concrete is prevented from being crushed by stress concentration; after the stress structure of the anchoring member is improved, the thickness of the steel plate can be reduced, so that the material is saved, and the weight is reduced.

Preferably, when the single-limb pier bridge No. 0 block construction device is used for single-limb pier bridge No. 0 block construction, the main longitudinal beam formed by detachably connecting the fixed section and the adjusting section is replaced by a main longitudinal beam which is within 3.5m in length and is of an integrated structure, namely the fixed section and the adjusting section do not exist.

When the integral main longitudinal beam structure is used for construction of a single-limb pier bridge No. 0 block, the problem of installation interference between double-limb piers does not need to be considered, and the integral main longitudinal beam structure can be directly adopted for construction convenience and reduction of manufacturing cost; in order to adapt to the maximum overhanging length bearing of the existing cantilever bridge with the span of less than 200m and balance the economy and the universality, the length of the customized main longitudinal beam is preferably 3.5 m.

The invention provides a construction method of an assembly type bracket structure applied to a single-limb pier bridge No. 0 block, which comprises the following steps:

step one, symmetrically mounting the assembled brackets on four sides of a construction pier stud; a plurality of transverse distribution beams are transversely arranged on the bracket of each side face of the construction pier stud;

step two, building a 0# block pouring template based on the construction platform provided by the bracket;

and step three, casting the 0# block in a layered mode.

When the assembly type bracket is applied to construction of a 0# block of a single-limb pier bridge, the assembly type bracket is symmetrically arranged around a construction pier column, a construction platform built by transverse distribution beams on the bracket frames around is used as a construction foundation, a layer of longitudinal distribution beam arrangement is not additionally arranged, a template is directly lapped on the transverse distribution beams, construction procedures are reduced, and materials are saved. The construction method of applying the assembly type bracket to the single-limb pier bridge 0# block is generally applicable to construction of the single-limb pier bridge 0# block within 150m and with the cantilever length within 3.5 m.

The invention provides a construction method of an assembly type bracket structure applied to a 0# block of a double-limb pier bridge, which comprises the following steps:

step one, symmetrically installing the assembled bracket on two construction pier columns along the longitudinal bridge direction; a plurality of transverse distribution beams are transversely arranged on the bracket of the bracket on the symmetrical surface of each construction pier stud;

step two, corresponding to the positions of flange plates on two sides of the No. 0 block, arranging a longitudinal distribution beam on the bracket;

step three, building a 0# block pouring template;

and step four, casting the 0# block in layers.

When the assembly type bracket is applied to construction of a 0# block of a double-limb pier bridge, the bracket is symmetrically installed on two construction pier columns from a longitudinal bridge direction, and a transverse distribution beam is arranged on a bracket frame of each group of brackets and used as a construction platform of a 0# block overhanging section; the longitudinal distribution beams are not added on the top and bottom plate sections and the web plate sections, and the longitudinal distribution beams are only arranged at the positions, corresponding to the flange plates, of the two sides and used as a 0# block flange plate construction platform, so that the effects of good stress performance and material saving are achieved on the premise that the basic construction requirements of the 0# block are met.

The clean pier column distance of the existing double-limb pier is generally 5m-6m, the above assembly type bracket construction double-limb pier bridge 0# block is adopted, the length of the main longitudinal beam is suitable, the arrangement of the position of the hinged pivot is reasonable, the adjusting section can be replaced according to actual working conditions, the interference of a bracket which is arranged relatively between the double-limb piers is avoided, the bracket can be better adapted to the construction working conditions, the universality and the construction flexibility of the bracket are improved, the bracket installation requirement is met, the construction safety of the bracket structure can be guaranteed simultaneously, the external load of the bracket is in the structure bearing allowable range, and the strength requirement of the bracket is met.

The construction method of the assembly type bracket applied to the double-limb pier bridge 0# block can be generally applied to construction of the double-limb pier bridge 0# block within 200m, with a pier column clear distance of 5m-6m and an overhanging length of 3 m.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. according to the design method of the assembly type bracket, construction conditions of 0# blocks of the bridge are summarized and counted based on a large amount of data, the external load range of the bracket is calculated firstly by summarizing the size of the 0# blocks according to the limit value and the bridge span classification, then the load and internal force change rule of each rod piece of the bracket are deeply analyzed through the transmission path of the external load on the bracket, the structure of the bracket is optimized, and the method is economical, reasonable and feasible in technology; by the design method, the designed bracket structure can be applied to the external load construction requirements of the bridge in the design range on the contrary, and the application proportion to the existing bridge is high. According to the design method of the assembly type bracket, the obtained bracket structure has the main longitudinal beam with the length of 2-3.5 m and the hinge fulcrum position with reasonable stress, the bracket structure can be suitable for the construction of casting a No. 0 block of a bridge in each cantilever within the range of 200m and the cantilever length within 3.5m, the bracket component can meet the external load requirement of the bridge, the deflection deformation is controllable, and the stress is safe; compared with the traditional bracket, the bracket structure obtained by the design method of the assembly type bracket provided by the invention has good universality, the problem that the traditional bracket is only applied to a specific bridge is fundamentally solved, the complex links of repeated customized design, review, change and the like for the brackets used in different bridge constructions are avoided, the cost is saved, the construction period is shortened, the whole application process is more humanized, the method can be suitable for the rapid design of different brackets required by different bridge constructions, and the universality is high.

2. According to the design method of the assembly type bracket, the design load is calculated in a simplified mode of layered pouring and chamfering, the actual stress condition of the bracket can be closer, the stress analysis is reasonable, and the material waste is greatly reduced; and the calculation process can be simplified, the design time is shortened, and the construction efficiency is improved.

3. The assembled bracket provided by the invention utilizes a sectional bracket structure, namely a main longitudinal beam is divided into a fixed section and an adjusting section, the end part of the fixed section is hinged with an inclined strut, the length of the fixed section is limited and the length (basically, the adjusting section) exceeding a hinged pivot is limited according to the actual working condition and the maximum applied load of the existing bridge, the stress safety is ensured, and simultaneously, the length of the main longitudinal beam is enabled to adapt to the construction of the cantilever length of a 0# block of the bridge by flexibly changing the length of the adjusting section, so that the size installation requirement of the double-limb pier bridge without interference is met, and the load requirement of the cantilever length range of the design of a single-limb pier or a double-limb pier is met, thus the bracket structure under the same customized size can be commonly applied to the construction of the 0# block of the single-limb pier bridge and the double-limb pier bridge, and one-to-one customization is not needed again according to the actual working condition. The bracket structure has high adaptability to construction conditions, improves the universality of the bracket in use and the construction flexibility, and simultaneously ensures the construction safety of the bracket structure, so that the external load of the bracket is within the allowable range of the structural performance bearing.

4. The assembly type bracket provided by the invention can be suitable for construction of a double-limb pier bridge with the span of within 200m, the cantilever length of within 3m and the pier column clear distance of 5m-6m and a 0# block on a single-limb pier bridge with the span of within 150m and the cantilever length of 3.5m, has strong adaptability to construction working conditions, good universality, high standard customization degree and low cost, is beneficial to popularization, solves the problem that the traditional bracket only aims at a single point of specific bridge application, omits complicated links such as repeated customization design, review, change and the like aiming at brackets used in different bridge constructions, saves the cost, shortens the construction period and is flexible in construction.

5. The assembly type bracket provided by the invention has the advantages that the included angle is fixed, the length of the fixed section of the prefabricated main longitudinal beam and the length of the inclined strut are fixed, the structure of the bracket is standardized while the stress safety of the structure is ensured, and the assembly type bracket is suitable for construction of a No. 0 bridge block in a design range so as to improve the universality of the bracket.

6. When the assembly type bracket is applied to construction of a 0# block of a single-limb pier bridge, the assembly type bracket is symmetrically arranged around a construction pier column, a construction platform built by transverse distribution beams on the bracket frames around is used as a construction foundation, a layer of longitudinal distribution beam arrangement is not additionally arranged, a template is directly lapped on the transverse distribution beams, construction procedures are reduced, and materials are saved. The construction method of applying the assembly type bracket to the single-limb pier bridge No. 0 block is generally applicable to construction of the single-limb pier bridge No. 0 block with the cantilever length within 150m and the cantilever length within 3.5 m.

7. When the assembly type bracket is applied to construction of a 0# block of a double-limb pier bridge, the bracket is symmetrically installed on two construction pier columns from a longitudinal bridge direction, and a transverse distribution beam is arranged on a bracket frame of each group of brackets and used as a construction platform of a 0# block overhanging section; the longitudinal distribution beams are not added on the top and bottom plate sections and the web plate sections, and the longitudinal distribution beams are only arranged at the positions, corresponding to the flange plates, of the two sides and used as a 0# block flange plate construction platform, so that the effects of good stress performance and material saving are achieved on the premise that the basic construction requirements of the 0# block are met.

8. The assembled bracket structure is designed and formed by combining a plurality of calculation methods, and the overall safety of the structure is greatly improved by checking different calculation methods and optimizing the structure.

Drawings

Fig. 1 is a general flow chart of the design for the fabricated bracket structure in embodiment 1.

Figure 2 is a transverse distribution beam design load distribution diagram.

FIG. 3 is a graph of the maximum change in shear for a transverse distribution beam.

FIG. 4 is a graph of the maximum value of the bending moment of the transverse distribution beam supports.

FIG. 5(a) is a schematic view showing a state where the load distribution length < l.

FIG. 5(b) is a load graph in which the load distribution length < l.

FIG. 5(c) is a shear diagram at a load distribution length < l.

FIG. 5(d) is a bending moment diagram at a load distribution length < l.

FIG. 6(a) is a schematic view showing a state where the load distribution length is not less than l.

FIG. 6(b) is a load graph in which the load distribution length is equal to or longer than l.

FIG. 6(c) is a shear diagram at a load distribution length of ≧ l.

FIG. 6(d) is a bending moment diagram when the load distribution length is not less than l.

FIG. 7 is a graph of the change in shear maximum for a triangular bracket main stringer.

Fig. 8 is a graph showing the variation of the maximum axial force of the brace of the triangular bracket.

Fig. 9 is a schematic structural view of a fabricated bracket according to embodiment 3.

Fig. 10 is a schematic view of the mounting structure of the bracket.

Fig. 11 is a schematic structural view of the main side member.

Fig. 12(a) is a schematic structural view of the first anchoring member at a certain viewing angle.

Fig. 12(b) is a structural view at another viewing angle of the first anchoring member.

Fig. 13 is a schematic structural view of the embedment box.

Fig. 14 is a schematic view showing a state when the anchor member is assembled with the embedded box.

Fig. 15 is a schematic view of the installation state of the fabricated bracket applied to the construction of the single pier bridge No. 0 block.

Fig. 16 is a schematic view of the installation state of the prefabricated double-limb pier bridge No. 0 block construction.

Icon: 1-a main longitudinal beam; 1A-a stationary section; 1B-an adjustment section; 2-diagonal bracing; 3-transverse distribution beams; 4-longitudinal distribution beams; 5-horizontal connection; 5A-positioning holes; 6-a first anchoring member; 6A-steel plate; 6B-preparing a hole; 7-a second anchoring member; 8-pier stud; 9-bracket rack; 10-steel strand wires; 11-a reinforcing plate; 12-pre-buried box.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

A method for designing a fabricated bracket, as shown in fig. 1, comprises the following main steps:

the method comprises the steps of firstly, counting the structural size of a cantilever pouring construction bridge according to a large number of past engineering cases, and data such as specifications, regulations, standards, design manuals and the like, wherein the structural size comprises a bridge type, a bridge span (counting bridges with span less than 200m in the embodiment), and 0# block size (such as box girder size, chamfer angle size and the like), establishing a 0# block box chamber structural size database according to different spans, and acquiring the minimum value and the maximum value of the size of each structural part of the 0# block, wherein the span is classified and calculated according to the embodiment by being less than or equal to 100m, 100 m-125 m, 125 m-150 m, 150 m-175 m and 175 m-200 m.

Step two, calculating the dead weight of the 0# block (concrete load q) according to the construction size ₂ ) (ii) a Further consider the formwork support load q in the construction process ₁ And a load q of a manual machine ₃ And a vibrating load q ₄ And obtaining design (surface) loads q at the corresponding positions of the bracket according to the 0# block web section, the top and bottom plate sections and the flange plate section areas, wherein q is q ₁ +q ₂ +q ₃ +q ₄ 。

Wherein, the load statistical table 1 of template (support) load, artificial machine load, load of vibrating is as follows:

TABLE 1 statistics of template (support) load, artificial machine tool load, and vibration load

When the load of the flange plate section formwork support is calculated, the support is calculated according to the bowl buckle support, and the height of the support is calculated according to 12m for the beams with different spans in order to simplify calculation aiming at the beam height between 3.6 and 11.5m (the common condition of the beam height of bridges with the span of less than 200 m). According to the statistical table of the self-weight of the bracket in the previous period, the self-weight of the bracket is calculated by using the data with the height of the bracket of 12m and the step pitch of 0.6 multiplied by 1.2m, the self-weight of the bracket is calculated to be 162.1kg through linear interpolation, and the surface load of the bracket is calculated to be 162.1 multiplied by 10/(0.6 multiplied by 1.2) ═ 2.25kN/m ² Adding the template surface load of 0.75kN/m ² Thus obtaining a template surface load of the bracket of 3.0kN/m ² 。

Selecting a bracket structure form, analyzing a bracket load distribution rule according to an external load transfer path (from a No. 0 block to each component of the bracket), and converting the load q range of design surfaces under different bridge spans into a linear load range; and (3) combining theoretical manual calculation and Midas electric calculation to obtain the design value range of internal force of each component of the bracket, obtain the arrangement of bracket rod pieces and design a 0# block bracket. The bracket is in a simplest form that a main longitudinal beam and an inclined strut are hinged, and is not provided with a vertical upright post, and transverse distribution beams are transversely distributed on the main longitudinal beam; for the double-limb pier, the longitudinal distribution beam is arranged on the bracket only in the area corresponding to the 0# flange plate position on two sides of the cross beam distribution beam to serve as the flange plate construction platform in the embodiment, and then the transmission path of the external load of the bracket in the area corresponding to the flange plate is as follows: the transmission paths of the longitudinal distribution beam, the transverse distribution beam, the main longitudinal beam and the inclined strut, which correspond to the top and bottom plate sections and the web plate sections, are as follows: a transverse distribution beam-main longitudinal beam-diagonal brace; for a single pier, without longitudinal distribution beams, the transfer path of the external load of the cradle in the corresponding flange plate area is: transverse distribution beam-main longitudinal beam-diagonal brace.

Specifically, the method comprises the following steps: (1) the arrangement pitch and angle of the bracket members are counted, and the following table 2 is shown:

TABLE 2 statistics of spacing and angle of existing bracket member arrangements

Calculating the design line load at the design position of the longitudinal distribution beam to obtain the design internal force of the longitudinal distribution beam: according to the span classification, calculating the design (line) load q' at the position of the corresponding flange plate section under different longitudinal distribution beam intervals and different transverse distribution beam intervals (upper and lower limit values are respectively taken), wherein x is the longitudinal distribution beam interval, and the longitudinal distribution beam interval in the embodiment refers to the longitudinal distribution beam interval at the position of the corresponding flange plate; calculating the maximum shearing force Q ═ beta × Q 'y and the maximum bending moment M ═ alpha × Q' y according to the designed line load ² Equal internal force (in the formula, alpha is the bending moment coefficient of the multi-span continuous beam, beta is the shearing force coefficient of the multi-span continuous beam, and both can be obtained according to an inquiry design manual); therefore, the maximum value and the minimum value of the linear load at the corresponding positions and the maximum value and the minimum value of the related internal force can be obtained. The design load and the internal force value of the flange plate section longitudinal distribution beam obtained through calculation are counted, summarized and selected, and the partial values are as follows in the following table 3:

table 3 shows the design load and internal force values of the longitudinal distribution beam

(2) Calculating the design load at the design position of the transverse distribution beam to obtain the design internal force of the transverse distribution beam: according to the span classification, calculating the design (line) loads q' which are respectively located at the corresponding positions of the web plate section, the top-bottom plate section and the flange plate section when the distance between the transverse distribution beams is respectively 0.6m at the lower limit, 0.7m at the upper limit and the lower limit of the corresponding 0# block structural size under the setting of the two bracket supports; calculating internal forces such as support counterforce, support shearing force, support bending moment, midspan bending moment and the like according to the design line load; thereby, the maximum value and the minimum value of the linear load and the maximum value and the minimum value of the related internal force of the corresponding position can be obtained. The load distribution of the external load on the transverse distribution beams is as shown in figure 2.

Wherein, support counter-force R:

R＝R _A ＝R _B ；

R＝q′ ₁₀ l ₁ +q′ ₂₀ l ₂ +q′ ₃₀ l ₃ ；

a support shear force Q:

+Q＝1/2q′ ₁₀ l ₁ +q′ ₃₀ l ₃ ；

-Q＝+Q-R；

support bending moment M _{Support base} And mid-span bending moment M _Midspan ：

l ₁ ＝D ₃ ，D ₃ the thickness of the web; l ₂ ＝1/2B ₂ -D ₃ ，B ₂ The box chamber is wide; l ₃ ＝B ₃ ，B ₃ The width of the flange plate is wide.

The calculated values of the design load and the internal force of the transverse distribution beam are statistically summarized and selected as shown in the following table 4:

table 4 shows the values of the design load and internal force components of the transverse distribution beam

(3) Analyzing the internal force of the longitudinal distribution beam and the transverse distribution beam, designing a bracket by taking the bridge span of 150m as a boundary according to the internal force design value distribution rule and the principles of structural stress safety and material full utilization, obtaining a reasonable configuration scheme of the longitudinal distribution beam and the transverse distribution beam, and concluding as the following table 5:

TABLE 5 distribution Beam layout optimization configuration and internal force design value parameter Table

As can be seen from fig. 3 and 4, the working condition 1: when the span L is 150m and the distance y between the transverse distribution beams is 0.7m, the shearing force is 146.2kN, and the bending moment is 105.8 kN.m; working condition 2: when the span L is 200m and the distance y between the transverse distribution beams is 0.6m, the shearing force is 164.8kN and the bending moment is 108.9 kN.m; compared with other working conditions, the internal force values of the working condition 1 and the working condition 2 are very close. Therefore, in the embodiment, the span L is 0-150m and is designed as a bracket type, and the span L is 150-200 m and is designed as a bracket type, so that the strength of the material is maximally applied when the cross sections adopted by the transverse distribution beams of the two types of brackets are the same.

(4) According to the total design load and the internal force of the triangular bracket, acquiring the internal force of a single main longitudinal beam and an inclined strut: firstly, according to the design surface load q of each area calculated in the step two, calculating the design line load q '(unit kN/m) of the area positions of the web section, the top plate section and the bottom plate section corresponding to the cross section of the 0# block according to the following formula, wherein q' ═ q ₁ '+∑q ₂ '+q ₃ '+q ₄ '。

Wherein the template (line) load q' ₁ ＝2q ₁ (l ₁ +l ₂ +l ₃ )；

Concrete (line) load sigma q' ₂ ＝2q ₂ (l ₁ +l ₂ +l ₃ )；

Crowd's machines load q' ₃ ＝2q ₃ (l ₁ +l ₂ +l ₃ )；

Vibrating load q' ₄ ＝2q ₄ (l ₁ +l ₂ +l ₃ )。

Then, the calculated design line load q' ═ q is calculated ₁ '+∑q ₂ '+q ₃ '+q ₄ And', calculating the design internal force of each bracket in the bracket, such as the shearing force of the main longitudinal beam, the support bending moment, the midspan bending moment, the axial force, the diagonal bracing axial force and the like. In this embodiment, since the number of the cow legs (also referred to as brackets) is 2, the load allocated to each cow leg is half of the total load, that is, the design load needs to be multiplied by 1/2.

During calculation, due to the fact that the cantilever lengths of bridges with different spans are different, loads acting on the bracket are considered to be divided into two cases, the first case is that the load distribution length is less than l, and the first case is shown in fig. 5(a) -5 (d); the second is that the load distribution length is larger than or equal to l, as shown in figures 6(a) to 6 (d); the support force and the internal force in two cases are correspondingly calculated:

in the first case, a formula is adopted for calculation, and the load length b is calculated according to the shortest overhanging length L ₂ The length is 1.0m by working condition calculation; in the second case, the length of the outer extension a is 1.0m, which is calculated by formula (II).

Statistics, such as the 0# block compartment size fraction statistics are given in table 6 below:

table 6 is a statistical table of the size parts of 0# block chamber

Overhanging length L of 0# block of bridge with span of less than 200m ₂ In the range of 1.0m-3.5m, the pier column clear distance of the double-limb pier bridge with the span of less than 200m is 5m-6 m; when the span L is less than 150m, the overhanging length of the 0# block is within 3.5m, and when the span L is more than or equal to 150m, the overhanging length of the 0# block is within 3.0 m. Therefore, according to the statistical range of the overhanging length, taking L as 150m as the basis of bracket type design; and it is easy to know that the span of the bridge with the single-limb pier structure is generally within 150 m. Considering the bracket stress and installation characteristics in the working conditions of the double-limb pier and the single-limb pier, the total length L' of the single-limb pier bridge design bracket with the span within 0-150m is designed to be 3.5m so as to be capable of adapting to the maximum cantilever length L of the bridge to the maximum extent ₂ The designed span length l is 2.5 m; for a double-limb pier bridge with a span of 0-200m, the total length l' of the bracket is calculated to be 3.0m, so that the bridge concrete weight between the double-limb piers can be borne and interference installation is avoided, and the design value of the span length l is 2.0 m.

(5) Carrying out internal force analysis on the main longitudinal beam and the inclined strut, designing a bracket by taking the bridge span length of 150m as a boundary according to the internal force design value distribution rule and the principles of structural stress safety and material full utilization to obtain a reasonable main longitudinal beam and inclined strut configuration scheme, and concluding as the following table 7:

table 7 shows the triangular bracket layout optimization configuration and internal force design value parameter table

Fig. 7 and 8 are internal force diagrams of the triangular bracket rod piece. As can be seen from the shear force variation trend graph of the main longitudinal beam, as shown in fig. 7, when the span L is less than 150m, the variation trend of the shear force increasing along with the span is significantly greater than the variation trend of the shear force increasing when the span L is greater than or equal to 150m, that is, the span L is 150m, which is a turning point of the internal force variation, and the shear force value of the span L is 150m is closer to that of the span L which is 200 m; the same applies to the strut axial force variation diagram shown in fig. 8. Therefore, when the span L is 0 to 150m and the span L is 150 to 200m, the main longitudinal beams and the bracket diagonal braces of the two types of brackets have the same section, and the strength of the material is applied to the maximum extent.

(6) Designing a No. 0 block bracket and rechecking strength, rigidity and stability: the method comprises the steps of confirming the section form of a component, designing the connection of the component, designing an anchoring system and designing corrosion prevention. The size of the bracket is designed based on the number of the two bracket legs, the length of a main longitudinal beam of the bracket is 2-3.5 m, and the distance a from the hinged center position of an inclined strut of the bracket and the main longitudinal beam to the free end position of the main longitudinal beam is not more than 1 m. The free end of the main longitudinal beam is the end of the main longitudinal beam far away from the construction pier stud.

In the design process, two types of bracket specifications with the same section form and material performance are designed according to the condition that the span length is 150m as a boundary, so that the universal construction of a 0# block is met in the span length range of two types of bridges with larger mechanical property difference, the designed bracket structure is generally applied, and the principles of structural stress safety and material full utilization are met.

In the embodiment, based on a large amount of data, construction conditions of 0# blocks of the bridge are summarized and counted, the external load range of the bracket is firstly calculated by summarizing the size of the 0# blocks according to the limit value and the bridge span classification, then the load and internal force change rules of all rod pieces of the bracket are deeply analyzed through the transmission path of the external load on the bracket, and the bracket structure is optimized, so that the method is economical, reasonable and technically feasible; by the design method, the designed size parameters of the bracket member can be applied to the construction requirements of external loads of bridges in a design range, and the application proportion of the bracket member to the existing bridges is high. The bracket with the main longitudinal beam with the length of 2 m-3.5m and the reasonable hinge fulcrum position can be suitable for construction of 0# block on a double-limb pier bridge with the span of within 200m, the cantilever length of within 3m and the pier stud clear distance of 5m-6m and a single-limb pier bridge with the span of within 150m and the cantilever length of within 3.5m, and the bracket component can meet the external load requirement of the bridge and has controllable deflection deformation.

Compared with the traditional bracket, the design method of the assembly type bracket provided by the embodiment has good universality, fundamentally solves the problem that the traditional bracket is only applied to a specific bridge, avoids the complex links such as repeated customized design, review, change and the like of the bracket used for different bridge constructions, saves the design flow and design cost, shortens the construction period, is more humanized in the whole application process, can be suitable for the rapid design of different brackets required for different bridge constructions, and has high universality.

Example 2

In the prior art, when a bracket structure (including size, quantity and structure) is designed, the design load of the bracket is often calculated in a way of pouring 0# block weight once, so that the bracket with the 0# block in field construction often has the problems of complicated structure, large volume, large quantity and the like, the material is wasted, and the economic cost is high; however, in actual construction, because the size and the weight of the block 0 are large, the construction quality, the safety, the convenience and other factors are considered, and layered pouring construction is usually adopted. The No. 0 block pouring construction is basically divided into two layers: the concrete load during the casting of the first layer is transferred to the bracket entirely, and the load during the casting of the second layer is not transferred to the bracket entirely because the first layer has actually developed a certain strength and rigidity.

In the second step of example 1, when calculating the design load of the bracket, the concrete (face) load q is calculated in the construction method of casting 0# block in layers ₂ (unit kN/m) ² ). In this embodiment, two pouring methods are used to calculate:

firstly, loading of concrete surface of web plate section: q. q.s ₂₁ ＝(H ₁ +0.5H ₂ )γ；

Wherein H ₁ Denotes the first layer casting height, H ₂ Represents the second layer casting height, and gamma represents the volume weight (unit kN/m) of 0# reinforced concrete ³ ) Taking 26kN/m ³ (ii) a The coefficient 0.5 represents the load deflection of the web plate section transmission bracket structure when the second layer is pouredAnd (5) reducing the coefficient.

Secondly, loading of concrete surface of the top and bottom plate sections: q. q.s ₂₂ ＝1.15(0.5D ₁ +D ₂ )γ；

Wherein D ₁ Indicates the thickness of the roof panel, D ₂ The thickness of the bottom plate is shown, the coefficient of 1.15 is the influence of chamfer concrete at the junction of the top plate, the bottom plate and the web plate, and the coefficient of 0.5 is the reduction coefficient of the load transmitted from the top plate to the bracket structure during the second pouring.

Specifically, when the concrete load of the top and bottom plate sections is calculated, the size of the upper chamfer and the size of the lower chamfer and the area of the top and bottom plate are counted and transmitted according to a 0.5 coefficient, and the ratio A of the area of the chamfer concrete to the total area of the concrete of the top and bottom plate sections is obtained according to the following formula ₂ /A：

Chamfer area A ₂ ＝(0.5ab+cd)；

Pure top and bottom plate area A ₁ (transfer by 0.5 delamination factor): a. the ₁ ＝l(0.5D ₁ +D ₂ )，l＝B ₂ -2D ₃ ；

The equivalent total area A of the top plate and the bottom plate is A ₁ +A ₂ ；

Wherein 0.5ab is the upper chamfer area and 0.5 is the transmission coefficient; cd is the lower chamfer area; b is ₂ Is the width of the bottom plate D ₃ Is the web width.

Analysis shows that for a bridge block No. 0 with the bridge span less than or equal to 200m, the ratio A2/A of the chamfer concrete area to the total concrete area of the top and bottom plate sections is 0.03-0.12 and less than 15%. Consequently, this embodiment adopts the calculation mode of simplifying the chamfer, and the concrete of chamfer department simplifies the equivalence to the bottom plate section concrete about will, and top bottom plate section concrete load includes pure top bottom plate area concrete load and upper and lower chamfer area department concrete load promptly: for bridges with bridge spans smaller than or equal to 200m, the area of No. 0 piece of chamfer concrete is replaced by multiplying the area of a pure top plate and a pure bottom plate by an amplification factor of 1.15.

By adopting the simplified chamfer calculation mode, the influence of concrete at the chamfer is considered, the influence of independently calculating the chamfer concrete load by adopting a complex calculation formula is avoided, and the design time is greatly shortened.

And thirdly, loading the concrete surface of the flange plate section:q ₂₃ ＝D ₄₅ ×γ；

wherein D ₄₅ Represents the average thickness of the flange plate, and gamma represents the volume weight of 0# reinforced concrete (unit kN/m) ³ ) Taking 26kN/m ³ 。

For the value of the thickness of the flange plate section, the checking calculation shows that when the thickness of the root part of the flange plate is taken for calculation, the bending moment in the longitudinal distribution beam span is more than 1.5 times of the bending moment calculated according to the trapezoidal load, and the safety margin is large; when the average value of the thickness of the root part and the end part is taken, the bending moment in the span of the longitudinal distribution beam is less than 1.15 times of the bending moment calculated according to the trapezoidal load, and the bending moment are relatively close to each other. Therefore, to simplify the calculation, the average of the thicknesses of the root and tip of the flange plate is taken for calculation.

Further, according to the bridge span classification, the upper and lower limit values of the sizes of the structural parts of the 0# block are counted, the concrete load is calculated respectively, and the minimum value and the maximum value of the concrete load are obtained, as shown in the following table 8:

table 8 is a statistical table of the minimum and maximum values of concrete load

Concrete load q ₂	Web segment	Top and bottom plate segments	Flange plate section
				Minimum value of	85.8	21.7	8.8
Maximum value	208.0	59.8	16.3

Example 3

The utility model provides an assembled bracket structure, as figure 9-11, includes two cow leg framves 9, and two cow leg framves 9 positions correspond the setting with single case roof beam both sides web central point respectively, can dismantle on two cow leg framves to be equipped with a plurality of horizontal distribution roof beams 3, and horizontal distribution roof beam 3 is connected two cow leg framves 9 as an organic whole, and the constructor of being convenient for builds the template, plays the effect that directly bears and transmit external load.

Each cow leg frame 9 comprises a main longitudinal beam 1 and an inclined strut 2, the main longitudinal beam 1 comprises a fixed section 1A and an adjusting section 1B, one end of the fixed section 1A is in butt joint with an end face bolt of the adjusting section 1B to enable the adjusting section 1B and the main longitudinal beam 1 to be fixedly connected into a whole, a lifting lug hinged with the inclined strut 2 is arranged at the bottom of the end, a lifting lug hinged with a first anchoring member 6 is arranged at the end part of the other end, and the first anchoring member 6 is used for being inserted into a pier stud 8; the other end of the inclined strut 2 is hinged with a second anchoring member 7, and the second anchoring member 7 is used for being inserted into a pier stud 8; the length of the fixed section 1A is 2 m-3 m, and the distance between the hinged center position of the inclined strut 2 and the fixed section 1A and the free end position of the main longitudinal beam 1 is not more than 1 m. It should be noted that, the adjusting section 1B can be selectively increased according to the actual working condition, and various lengths can be prefabricated and freely combined. The free end of the main longitudinal beam 1 refers to the opposite end of the main longitudinal beam 1 hinged with the end of the first anchoring member 6, and when the adjusting section 1B is not required to be installed in construction, the free end of the main longitudinal beam 1 refers to the end part of the fixing section 1A which can be connected with the adjusting section 1B; when the adjusting section 1B is installed in construction, the free end of the main longitudinal beam 1 is the outermost side of the adjusting section 1B.

The assembly type bracket provided by the embodiment utilizes a sectional type bracket structure to divide a main longitudinal beam into a fixed section and an adjusting section, the end part of the fixed section is hinged with an inclined strut, and the adjusting section is detachably connected with the fixed section; while defining a fixed segment length of 2-3 m. The adoption of the separated structure design considers the construction environment of the double-limb pier cantilever bridge with the span of 200m below at present: the net distance between the pier columns is generally 5m-6 m; when setting up the bracket in two buttress inboards and being relative setting, adopt the main longitudinal beam that is less than 1/2 pier stud net apart from length to be under construction, two brackets can not take place to interfere and the centre can reserve enough construction space and avoid dieing, and structural arrangement is reasonable, construction convenience is nimble. When the single-limb pier bridge 0# block with the maximum cantilever length of 3.5m is used for construction, the length of the main longitudinal beam can reach 3.5m to adapt to the construction of the maximum cantilever length by flexibly replacing the length of the adjusting section under the size of a prefabricated bracket suitable for the construction of the double-limb pier, and the single-limb pier bridge 0# block is not required to be customized one by one again according to the actual working condition. The length (basically, the adjusting section) exceeding the hinge pivot is limited to be less than or equal to 1m based on the fixed section with the length of 2-3m, so that the bearing requirement of the cantilever length of the span bridge in a design range on the bracket can be met, the construction safety of the bracket structure is ensured, the length of the main longitudinal beam and the position of the hinge pivot can adapt to the external load of the bridge, and the deflection deformation is controllable.

Specifically, the first anchor member 6 and the second anchor member 7 are identical in structure, the first anchor member 6 being longer than the second anchor member 7; as fig. 12(a), 12(B), be equipped with two steel sheet 6A and preformed hole 6B on the first anchor component 6, steel sheet 6A is used for vertical grafting on construction pier 8, and preformed hole 6B is located two steel sheet 6A middle parts, and preformed hole 6B is used for the anchor to connect the counter-pull steel strand wires. Correspondingly, as shown in fig. 13, pre-embedded boxes 12 are pre-arranged on the construction pier stud 8 at positions corresponding to the first anchoring member 6 and the second anchoring member 7; when the embedded box 12 is used for binding the pier stud reinforcing steel bars, the embedded box is embedded in the construction pier stud 8; the embedded box 12 is provided with a groove which is matched and embedded with the steel plate 6A in shape and a hole for the steel strand to pass through, and the size of the groove is slightly larger than that of the steel plate at the end part of the anchoring system so as to be convenient for installation within an allowable error. The embedded box 12 is used for positioning an anchoring system for installation; on the other hand, the pier stud concrete is locally reinforced.

When the span of the bridge is less than 150m, the distance between two adjacent transverse distribution beams 3 is not more than 0.7m (in the embodiment, 0.7m is preferred and cannot exceed 0.7m, otherwise the transverse distribution beams 3 cannot bear the load and damage the structure); when the bridge span is greater than or equal to 150m and less than 200m, the distance between two adjacent transverse distribution beams 3 is set to be not greater than 0.6m (0.6 m is preferred in the embodiment).

Furthermore, one cross-linking 5 can be detachably connected between two inclined struts 2 and between two main longitudinal beams 1 respectively, two bracket legs 9 are connected into a whole, and the stability of the bracket structure is enhanced. The horizontal connection 5 is a truss structure which is connected into a whole by a plurality of concave groove steel rod pieces, and comprises two parallel arranged main rods and a plurality of intermediate rods for connecting the two main rods, wherein a plurality of positioning holes 5A used for being connected with bolts of the inclined strut 2/main longitudinal beam 1 are arranged on the two main rods, and the plurality of positioning holes 5A are closely and continuously arranged and can adapt to the change of the installation distance between the two bracket supports 9.

Above-mentioned assembled bracket is arranged in the symmetry and installs and pour 0# piece in order to construct on 8 tops of pier stud, and the two pairs of brackets that the symmetry set up are fixed through pre-buried steel strand wires counter-pulling in 8 pier studs, all wear to establish the steel strand wires between the relative first anchor component 6 that sets up and between the relative second anchor component 7 that sets up. Compared with the existing counter-pulling finish rolling twisted steel, the steel strand has high toughness, high strength and better tensile property.

In the embodiment, the corbels with two specifications are customized, the length specifications of the main longitudinal beam 1 and the inclined strut 2 are standardized, and the installation angle between the main longitudinal beam 1 and the inclined strut 2 is controlled to be 60 degrees (can float within the range of 45-60 degrees), so that the bracket is less stressed and safer in structure compared with an included angle of 45 degrees; the length of the fixed section 1A is 2420mm, the length of the inclined strut 2 is 4340mm, the length of the fixed section 1A is 2920mm, and the length of the inclined strut 2 is 5340 mm; the adjustment section 1B may be provided in various lengths, such as 450mm, 750mm, etc.

The fabricated bracket provided by the embodiment is suitable for construction of 0# block of a span cast-in-place bridge with the span of less than 200m, particularly suitable for construction of 0# block of a double-limb pier bridge with the span of within 200m, the cantilever length of within 3m and the pier column clear distance of 5m-6m and a single-limb pier bridge with the span of within 150m and the cantilever length of within 3.5m, and the 0# block preferably has a single-box single-chamber section structure with the bottom surface width of within 7 m.

The assembly type bracket that this embodiment provided, strong adaptability to the construction operating mode, the commonality is good, standard customization degree is high, with low costs, does benefit to the popularization, has solved "single-point" problem that traditional bracket only used to specific bridge, has removed from and all need carry out loaded down with trivial details links such as repeated customization design, review and change to the bracket that different bridge constructions used, has saved the cost, has shortened the time limit for a project, and the construction is nimble.

Example 4

When the single-limb pier bridge No. 0 block is used for construction, the main longitudinal beam formed by detachably connecting the fixed section and the adjusting section in the embodiment 3 is replaced by the main longitudinal beam which is within 3.5m in length and is of an integrated structure. Namely, the main longitudinal beam of the bracket has no fixed section and no adjusting section; one end of the main longitudinal beam is hinged to a first anchoring member used for being connected with a pier stud, the other end of the main longitudinal beam is hinged to the end portion of the inclined strut, the distance a from the hinged center position of the main longitudinal beam and the inclined strut to the free end position of the main longitudinal beam is not larger than 1m, and the other end of the inclined strut is hinged to a second anchoring member.

The installation included angle theta between the inclined strut and the main longitudinal beam is 60 degrees.

Example 5

Since the anchor member structure (first anchor member/second anchor member) in embodiment 3 is subjected to a shearing force in the vertical direction, stress is concentrated at the top and bottom of the steel plate, and if the steel plate has a rectangular cross section, the thickness of the steel plate is usually made thicker to improve the shearing resistance.

In this embodiment, based on the anchoring member structure provided in embodiment 3, the steel plate 6A for inserting and constructing the pier stud is preferably designed to have an i-shaped cross section, as shown in fig. 12(a) and 12(b), so as to increase the contact area between the steel plate and the pier stud concrete and avoid stress concentration and crushing local concrete; after the stress structure of the anchoring member is improved, the thickness of the steel plate can be reduced, so that the material is saved, and the weight is reduced. Specifically, the reinforcing plates 11 may be butt-welded vertically at the top and bottom positions of each steel plate, respectively, to be consolidated into one body; correspondingly, the embedded boxes 12 in the construction pier are matched and clamped with the anchoring components, as shown in fig. 13 and 14.

Example 6

A construction method of applying the fabricated bracket structure to a single-limb pier bridge No. 0 block is based on the fabricated bracket in embodiment 3 or the fabricated bracket structure in embodiment 4, and comprises the following steps as shown in figure 15:

the construction method comprises the steps that firstly, the top ends of the construction pier studs 8 are symmetrically provided with the brackets on the side surfaces in the longitudinal direction and the transverse direction respectively, wherein two bracket supports in the longitudinal direction are arranged at the center of webs on two sides of a single box girder 0# block to be poured, and a plurality of transverse distribution girders are transversely arranged on the bracket supports on each side surface of the construction pier studs 8. The bracket arranged along the longitudinal bridge direction provides a construction platform for supporting and pouring the overhanging section of the bridge, and the bracket arranged along the transverse bridge direction provides a construction platform for supporting and pouring flange plates at two sides of the No. 0 block by taking the transverse distribution beam as a construction foundation; no additional longitudinal distribution beams 4 need to be built on the bracket.

Because the bridge section of encorbelmenting compares 0# piece edge of a wing section load bigger, for reasonable atress and utilization of resources, it is better to adopt different specifications to the bracket to horizontal bridge and vertical bridge. The use specification of the mounting bracket along the longitudinal bridge direction is as follows: the length of the main longitudinal beam 1 is 2920mm, and the length of the inclined strut 2 is 5340 mm; the use specification of the mounting bracket along the transverse bridge direction is as follows: the length of the main longitudinal beam 1 is 2420mm, and the length of the inclined strut 2 is 4340 mm. The main longitudinal beam 1 of the longitudinal direction bracket is slightly lower than the main longitudinal beam 1 of the transverse direction bracket, and two ends of the transverse distribution beam 3 of the transverse direction bracket are arranged on the transverse distribution beam 3 of the longitudinal direction bracket; an included angle of 60 degrees is formed between the main longitudinal beam 1 and the inclined strut 2.

And step two, building a 0# block pouring template based on the construction platform provided by the bracket.

And step three, casting the 0# block in layers, wherein the casting is carried out in two layers.

When this embodiment is applied to the construction of single limb mound bridge 0# piece with above-mentioned assembled bracket, the symmetry is installed around the construction pier stud to the construction platform that the horizontal distribution roof beam of bracket frame was built all around is the construction basis, no longer adds the vertical distribution roof beam of one deck and arranges, and directly with the template overlap joint on horizontal distribution roof beam, reduced construction process, saved the material. The construction method of applying the assembly type bracket to the single-limb pier bridge 0# block is generally applicable to construction of the single-limb pier bridge 0# block within 150m and with the cantilever length within 3.5 m.

Example 7

A construction method of applying the fabricated bracket structure to a double-limb pier bridge No. 0 block is based on the fabricated bracket structure in embodiment 1, and comprises the following steps as shown in figure 16:

the top ends of two construction pier columns 8 are symmetrically provided with brackets on the double-limb piers along the longitudinal bridge direction, two brackets of the brackets are arranged corresponding to the centers of webs on two sides of a 0# block of a single box girder to be poured, wherein the two brackets in the middle of the double-limb pier are preferably reserved with a distance of 10 centimeters so as to be convenient for construction and installation and avoid top death. A plurality of transverse distribution beams are transversely arranged on the bracket of the bracket on the symmetrical surface of each construction pier stud;

and step two, a construction platform is provided for pouring the 0# blocks along the flange plates on the two sides of the transverse bridge, and the longitudinal distribution beams 4 are distributed on the transverse distribution beams 3 on the two sides of the bracket along the transverse bridge and below the corresponding 0# block flange plates.

And step three, building a 0# block pouring template.

And step four, casting the 0# block in a layered mode.

In the embodiment, when the assembly type bracket is applied to construction of a 0# block of a double-limb pier bridge, the brackets are symmetrically arranged on two construction pier columns from a longitudinal bridge direction, and a horizontal distribution beam is arranged on a bracket frame of each group of brackets and used as a construction platform of a 0# block overhanging section; the longitudinal distribution beams are not added on the top and bottom plate sections and the web plate sections, and the longitudinal distribution beams are only arranged at the positions, corresponding to the flange plates, of the two sides and used as a 0# block flange plate construction platform, so that the effects of good stress performance and material saving are achieved on the premise that the basic construction requirements of the 0# block are met.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A method of designing a fabricated bracket, comprising the steps of:

classifying the construction size of the 0# block according to the span of the bridge to obtain a size limit value, respectively corresponding to the areas of the web plate section, the top and bottom plate section and the flange plate section, and calculating to obtain a concrete load q of the 0# block ₂ Range, thereby obtaining a design surface load q range, i.e., a bracket external load range, where the design surface load q comprises a formwork support load q ₁ Concrete load q ₂ And a load q of a manual machine ₃ And a vibrating load q ₄ ；

Selecting a bracket structure form, analyzing a bracket load distribution rule according to an external load transmission path of the bracket, and converting the design surface load q into a design line load q' to obtain the internal force design value range of each rod piece of the bracket; according to the internal force design value distribution rule of each component of the bracket, according to the principle of structural stress safety and material full utilization, the bracket rod piece arrangement scheme is obtained to design the bracket: the bracket comprises a bracket frame, the bracket frame comprises a main longitudinal beam and an inclined strut, the inclined strut is hinged with the main longitudinal beam, the size of the bracket is designed based on the number of the two bracket frames, the length of the main longitudinal beam of the bracket is 2-3.5 m, and the distance a from the hinged center position of the inclined strut of the bracket and the main longitudinal beam to the free end position of the main longitudinal beam is not more than 1 m;

fourthly, rechecking the strength, the rigidity and the stability of the bracket;

and the angle theta in the first step is an installation included angle theta between the inclined strut and the main longitudinal beam.

2. The method of claim 1, wherein in step one, a database of data parameters for a bridge construction of less than 200m span cast-in-place cantilever is created.

3. The method for designing an assembled bracket according to claim 1, wherein in the second step, the design surface load q is calculated by simulating layered casting and simplified chamfering, wherein the concrete loads corresponding to the position areas of the web plate section, the top and bottom plate sections and the flange plate section are respectively calculated and obtained according to the following formula:

web sections: q. q.s ₂₁ ＝(H ₁ +0.5H ₂ )γ；

Wherein H ₁ Represents the first layer casting height of 0# block, H ₂ Representing the casting height of the second layer of the 0# block, and gamma represents the volume weight of the 0# reinforced concrete; the coefficient 0.5 represents the load reduction coefficient of the web plate section transmission bracket structure during second layer pouring;

top and bottom plate sections: q. q.s ₂₂ ＝1.15(0.5D ₁ +D ₂ )γ；

thirdly, flange plate sections: q. q.s ₂₃ ＝D ₄₅ ×γ；

Wherein D ₄₅ Indicating the average thickness of the flange plate.

4. The method of claim 1, wherein the step three includes obtaining the design line load range on the longitudinal distribution beam according to the external face load, obtaining the design range of the internal force of the longitudinal distribution beam, and calculating according to the following formula:

designing a line load q' ═ qxx;

the maximum shearing force Q is β × Q' y;

maximum bending moment M ═ α × q' y ² ；

5. The method of claim 1, wherein the step three includes obtaining the design line load range on the transverse distribution beam according to the external face load, obtaining the internal force design range of the transverse distribution beam, and calculating according to the following formula:

designing a line load q' ═ qxy;

support reaction force R:

R＝R _A ＝R _B ；

R＝q′ ₁₀ l ₁ +q′ ₂₀ l ₂ +q′ ₃₀ l ₃ ；

a support shear force Q:

+Q＝1/2q′ ₁₀ l ₁ +q′ ₃₀ l ₃ ；

-Q＝+Q-R；

Wherein y represents the transverse distribution beam spacing, R _A Representing the reaction force of the abutment at point A, R _B Representing the abutment reaction force, q 'at point B' ₁₀ Representing the corresponding web segment line loads, q 'on the transverse distribution beam' ₂₀ Representing the corresponding roof and floor segment line loads, q ', on the transverse distribution beam' ₃₀ Representing the line load of the corresponding flange plate section on the transverse distribution beam;

l ₁ ＝D ₃ ，D ₃ the thickness of the web; l ₂ ＝1/2B ₂ -D ₃ ，B ₂ The box chamber is wide; l ₃ ＝B ₃ ，B ₃ The width of the flange plate is wide;

6. The design method of a fabricated bracket according to claim 1, characterized in that in step three, the design line load range on a single bracket is obtained according to the external face load, and the design internal force ranges of the main longitudinal beam and the inclined strut are respectively obtained; and obtaining an arrangement scheme of the main longitudinal beam and the inclined strut according to the internal force configuration.

7. A fabricated bracket designed according to the design method of the fabricated bracket as claimed in any one of claims 1 to 6, comprising at least two cow leg frames (9), wherein each cow leg frame (9) comprises a main longitudinal beam (1) and an inclined strut (2), the main longitudinal beam (1) comprises a fixed section (1A) and an adjusting section (1B), the fixed section (1A) is detachably connected with the adjusting section (1B) to enable the adjusting section (1B) to be fixedly connected with the fixed section (1A) into a whole, one end of the fixed section (1A) is hinged with a first anchoring member (6), the first anchoring member (6) is used for connecting a pier stud (8), the other end of the fixed section (1A) is hinged with one end of the inclined strut (2), and the other end of the inclined strut (2) is hinged with a second anchoring member (7), the second anchoring member (7) is used for connecting the pier stud (8); the length of the fixed section (1A) is 2-3m, and the distance a from the hinged center position of the inclined strut (2) and the fixed section (1A) to the free end position of the main longitudinal beam (1) is not more than 1 m.

8. A fabricated bracket according to claim 7, further comprising a plurality of transverse distribution beams (3), wherein the plurality of transverse distribution beams (3) are detachably connected to all the main longitudinal beams (1), and the distance between two adjacent transverse distribution beams (3) is not more than 0.7 m.

9. A fabricated bracket according to claim 8, characterised in that when the bridge span is less than 150m, the spacing between two adjacent transverse distribution beams (3) is not more than 0.7 m; when the bridge span is more than or equal to 150m and less than 200m, the distance between two adjacent transverse distribution beams (3) is not more than 0.6 m.

10. An assembly carriage as claimed in claim 7, characterised in that it further comprises a cross-piece (5), said cross-piece (5) being provided with a plurality of successive positioning holes (5A); all the inclined struts (2) are connected through one cross connection (5), and/or all the main longitudinal beams (1) are connected through one cross connection (5).

11. A fabricated bracket according to claim 7, characterised in that the angle θ between the brace strut (2) and the main stringer (1) is 45 ° -60 °.

12. A mounting bracket according to claim 11, wherein said included mounting angle is 60 °.

13. A fabricated bracket according to claim 7, characterised in that the end surface of the fixing section (1A) is bolted to the end surface of the adjusting section (1B).

14. An assembly carrier as claimed in claim 7, characterised in that the carrier is provided with two bracket legs (9), and the two bracket legs (9) are respectively arranged at the corresponding positions of the centers of the webs on the two sides of the 0# single box girder block.

15. A fabricated bracket according to any one of claims 7-14, characterised in that the first (6) and second (7) anchoring members are of identical construction, the first (6) anchoring member being longer than the second (7) anchoring member.

16. The assembly type bracket of claim 15, wherein the first anchoring member (6) is provided with two steel plates (6A) and a preformed hole (6B), the steel plates (6A) are used for being vertically inserted into a construction pier stud (8), the preformed hole (6B) is positioned in the middle of the two steel plates (6A), and the preformed hole (6B) is used for anchoring a counter-pull steel strand.

17. A fabricated bracket according to claim 16, characterised in that the cross-sectional shape of the steel plate (6A) is rectangular or i-shaped.

18. A fabricated bracket according to any one of claims 7-14, characterised in that when used in the construction of single pier bridge No. 0, the main longitudinal beam (1) formed by the detachable connection of the fixed section (1A) and the adjustable section (1B) is replaced by a main longitudinal beam of a one-piece construction within 3.5m in length.

19. A construction method of applying an assembly type bracket structure to a single-limb pier bridge No. 0 block comprises the following steps:

step one, symmetrically installing a fabricated bracket according to any one of claims 7 to 18 on four sides of a construction pier stud (8); a plurality of transverse distribution beams (3) are transversely arranged on the bracket on each side surface of the construction pier column (8) and the bracket frame (9) of the bracket;

and step three, casting the 0# block in a layered mode.

20. A construction method for applying an assembled bracket structure to a double-limb pier bridge No. 0 block comprises the following steps:

step one, symmetrically installing an assembly type bracket according to any one of claims 7 to 18 on two construction pier studs (8) along the longitudinal bridge direction; a plurality of transverse distribution beams (3) are transversely arranged on the bracket on the symmetrical surface of each construction pier column (8) and the bracket frame (9) of the bracket;

step two, arranging longitudinal distribution beams (4) on the brackets corresponding to the positions of flange plates on two sides of the No. 0 block;

step three, building a 0# block pouring template;

and step four, casting the 0# block in a layered mode.