CN111663449A - Combined cast-in-place box girder support system and construction method - Google Patents

Abstract

The invention provides a combined cast-in-place box girder support system and a construction method. An upper hoop and a lower hoop are installed on each middle pier of a bridge, and a support rod is provided between the corbels of the upper hoop and the lower hoop , a steel pipe column is installed near each side pier of the bridge, the bottom of the steel pipe column is supported on the ground concrete foundation, the upper hoop of the transverse bridge and the top of the steel pipe column are respectively set up with load-bearing beams, and the top of the two load-bearing beams of each span is erected along the bridge direction. Bailey longitudinal beam, the distribution beam is erected on the Bailey longitudinal beam in the transverse direction, the distribution beam is installed with a full house support, and the cast-in-place box girder formwork system is installed on the top of the full house support. The invention is suitable for geological conditions such as complex terrain conditions in mountainous areas, difficult foundation treatment, high pier columns, etc., and has simple structure, less material input and high safety.

Description

A combined cast-in-place box girder support system and construction method

technical field

The invention belongs to the technical field of cast-in-place box girder construction in bridge engineering, and in particular relates to a combined cast-in-place box girder support system and a construction method, which are particularly suitable for existing constructions under the conditions of complex terrain conditions in mountainous areas, difficult foundation treatment, high pier columns and the like. Casting box girder construction.

Background technique

At present, the commonly used supports for cast-in-place box girder construction mainly include full-chamber supports and steel pipe supports. The full hall support has high safety, but it is only suitable for areas with no traffic requirements below, the pier height is within 15m, the foundation conditions are good, and the terrain is relatively flat; the steel pipe support can be used as long as the clearance under the bridge can meet the erection requirements, but in steep terrain , Under the weak geological conditions, the construction of the steel pipe column foundation is more difficult, which increases the construction cost, and when the pier column is high, the steel pipe column erection is relatively high, the high-altitude operation workload is large, the material input is large, and the construction risk is high. In the case of complex terrain conditions in mountainous areas, difficult foundation treatment, and high piers and columns, how to not only ensure the safety of cast-in-place box girder construction, but also reduce the cost input and ensure the construction period is a practical problem faced by the construction unit.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a combined cast-in-place box girder support system and construction method suitable for complex terrain conditions in mountainous areas, difficult foundation treatment, high pier columns, etc., and simplify the support under the premise of ensuring safety. Structural design, reducing the investment of temporary materials and shortening the construction period.

In order to achieve the above purpose, the present invention provides a combined cast-in-place box girder support system, which is characterized in that: an upper hoop and a lower hoop are installed on each middle pier of the bridge, and the cows of the upper hoop and the lower hoop are installed. There are support rods between the legs, and a steel pipe column is set near each side pier of the bridge. The bottom of the steel pipe column is supported on the ground concrete foundation, and the top of the steel pipe column is at the same elevation as the top of the upper hoop; A load-bearing beam is set up on the top of the upper hoop on the middle pier and on the top of the steel pipe column close to the side pier, and a Bailey longitudinal beam is set up on the top of the two load-bearing beams of each span along the bridge direction. The bridge is provided with an I-beam distribution beam at a certain interval, and a full hall bracket is installed on the distribution beam. The lower end of each vertical rod of the full hall bracket is supported on the upper flange plate of the I-beam distribution beam, and the top of the full hall bracket is supported. A cast-in-place box girder formwork system is installed.

The method of using the above-mentioned combined cast-in-place box girder support system for construction is characterized in that, comprising the following steps:

(1) Prepare the hoop, load-bearing beam, distribution beam, and steel pipe column according to the size of the bridge pier; assemble the Bailey longitudinal beam into a whole on the ground, and fix the reinforcing chord on the lower chord of the Bailey longitudinal beam through matching bolts;

(2) Use lifting equipment to install and fix the upper hoop and the lower hoop on the mid-span pier column according to the design position, install the lower hoop first, and then install the upper hoop;

(3) Construct the concrete expansion foundation on the bottom side of the side pier. After the concrete strength reaches the specification requirements, use the lifting equipment to hoist the steel pipe column on the side pier expansion foundation, and install the corresponding reinforcing structural accessories;

(4) A truss-type load-bearing beam is installed on the upper hoop of the middle pier of the transverse bridge, and a support rod is installed between the corbels of the upper and lower hoop, and the lower chord of the truss-type load-bearing beam is limited between the support rod and the outer wall of the pier body;

(5) Use lifting equipment to hoist the Bailey longitudinal beams along the bridge on the load-bearing beams of each span, and install corresponding reinforcement components;

(6) Lay profiled steel distribution beams on the Bailey longitudinal beams according to the design requirements, and install corresponding reinforcement components;

(7) A full hall support is erected on the profile steel distribution beam;

(8) Set up a formwork system on the full hall support according to the design requirements;

(9) After the preloading of the support meets the requirements of the specification, the cast-in-place box girder construction shall be carried out; when the concrete on both sides of the middle pier is poured, the unbalanced weight on both sides shall be controlled so as not to exceed the bearing capacity of the pier column itself;

(10) After the concrete strength of the cast-in-place box girder reaches the specification requirements or the prestressed tension is completed, the entire support is removed.

Compared with the prior art, the present invention has beneficial effects in the following aspects:

(1) Economy: If steel pipe supports or full-house supports are used for construction, the steel pipes and section steel materials used for erecting single-span supports are about 40t, and the labor and machinery costs are high, and the cost of foundation reinforcement treatment needs to be increased at the same time; As the height of the bridge pier increases, the amount of steel consumed and the construction cost will further increase; the materials required for a single span of the present invention are mainly 8 hoops with a weight of about 2t, which saves a lot of temporary materials and foundation treatment costs.

(2) Construction period: the construction of steel pipe supports or full house supports needs to carry out processes such as foundation treatment, steel pipe column ground processing, parallel high-altitude welding, etc., there are many components erected, and the construction period is long, and the present invention avoids the above-mentioned problems well, Can greatly save construction time.

(3) Construction safety and quality: In the case of complex terrain conditions in mountainous areas, difficult foundation treatment, and high piers and columns, steel pipe supports or full hall supports are used for construction, which is difficult to deal with the foundation and difficult to control the quality; high hoisting height, high-altitude operation The quantity is large, and the safety risk of the bracket installation and dismantling operation is large; the invention has simple construction technology, easy quality control, low construction difficulty and low safety risk.

Description of drawings

1 is a schematic diagram of a structure along the bridge direction according to an embodiment of the present invention;

Fig. 2 is the cross-bridge structural schematic diagram of the present invention at the middle pier;

FIG. 3 is a schematic diagram of the transverse bridge structure at the side pier of the present invention.

Detailed ways

As shown in Figure 1, Figure 2, Figure 3, a combined cast-in-place box girder support system provided by the present invention is provided with an upper hoop 3 and a lower hoop 4 on each mid-span pier 1 of the bridge. Each hoop includes two semi-circular hoop plates. There are connecting plates on both sides of the hoop plates. The two hoop plates are fastened to the pier. The connecting plates of the two hoop plates are connected by high-strength bolts. The plate and the pier body are tightly fixed, and the connecting plates of the two hoop plates are combined to form a hoop corbel; a support rod 5 is arranged between the corbels of the upper hoop 2 and the lower hoop 3, and the upper and lower ends of the support rod 5 are respectively connected with the upper and lower ends of the hoop. The bottom of the corbel of the hoop and the top of the corbel of the lower hoop are tight; close to each side pier 2 of the bridge, a steel pipe column 6 is respectively set, and the bottom of the steel pipe column 6 is supported on the ground concrete foundation 7, and the top of the steel pipe column Consistent with the top elevation of the upper hoop 3; the top of the upper hoop 3 on the middle pier and the top of the steel pipe column 6 close to the side pier are respectively set up with a load-bearing beam 8 along the bridge direction at the top of each span of the bridge. The top of the two load-bearing beams 8 is erected with a Bailey longitudinal beam 9, and on the Bailey longitudinal beam 9, an I-beam distribution beam 10 is erected at a certain interval in the transverse bridge direction. The I-beam distribution beam adopts conventional I20a steel, and the distribution beam A full house bracket 11 is installed on the full house bracket 10 , the lower end of each vertical rod of the full house bracket 11 is supported on the upper flange plate of the I-beam distribution beam, and a cast-in-place box girder formwork system 12 is installed on the top of the full house bracket 10 .

The full house bracket can be of bowl buckle or disc buckle structure, which can be used to adjust the vertical and horizontal slope of the bracket to ensure that the beam shape meets the requirements.

During specific implementation, the load-bearing beam 7 erected on the upper hoop 3 can adopt a truss-type bearing structure, the upper chord is supported on the top of the upper hoop, the lower chord is located between the connecting rod between the upper and lower hoop and the outer wall of the pier, the upper chord and Diagonal bracing is adopted between the lower chords; the load-bearing beam 7 erected on the top of the steel pipe column 6 can be a horizontal bar-type load-bearing beam, and its specification and model are consistent with the upper chord of the truss structure load-bearing beam erected on the upper hoop.

The above-mentioned combined cast-in-place box girder support system is used for the construction of the cast box girder, and the specific method is as follows:

(1) Prepare the hoop, load-bearing beam, distribution beam, and steel pipe column according to the size of the bridge pier; assemble the Bailey longitudinal beam into a whole on the ground, and fix the reinforcing chord on the lower chord of the Bailey longitudinal beam through matching bolts;

(2) Use lifting equipment to install and fix the upper hoop and the lower hoop on the mid-span pier column according to the design position, install the lower hoop first, and then install the upper hoop;

(3) Construct the concrete expansion foundation on the bottom side of the side pier. After the concrete strength reaches the specification requirements, use the lifting equipment to hoist the steel pipe column on the side pier expansion foundation, and install the corresponding reinforcing structural accessories;

(4) A truss-type load-bearing beam is installed on the upper hoop of the middle pier of the transverse bridge, and a support rod is installed between the corbels of the upper and lower hoop, and the lower chord of the truss-type load-bearing beam is limited between the support rod and the outer wall of the pier body;

(5) Use lifting equipment to hoist the Bailey longitudinal beams along the bridge on the load-bearing beams of each span, and install corresponding reinforcement components;

(6) Lay profiled steel distribution beams on the Bailey longitudinal beams according to the design requirements, and install corresponding reinforcement components;

(7) A full hall support is erected on the profile steel distribution beam;

(8) Set up a formwork system on the full hall support according to the design requirements;

(9) After the preloading of the support meets the requirements of the specification, the cast-in-place box girder construction shall be carried out; when the concrete on both sides of the middle pier is poured, the unbalanced weight on both sides shall be controlled so as not to exceed the bearing capacity of the pier column itself;

(10) After the concrete strength of the cast-in-place box girder reaches the specification requirements or the prestressed tension is completed, the entire support is removed.

Claims (3)

1. a combined cast-in-place box girder support system is characterized in that: an upper hoop and a lower hoop are installed on each middle pier of the bridge, and a support rod is provided between the corbels of the upper hoop and the lower hoop , a steel pipe column is set near each side pier of the bridge, the bottom of the steel pipe column is supported on the ground concrete foundation, and the top of the steel pipe column is at the same elevation as the top of the upper hoop; A load-bearing beam is set up on the top of the hoop and on the top of the steel pipe column close to the side pier, and Bailey longitudinal beams are erected on the top of the two load-bearing beams of each span along the bridge direction, and on the Bailey longitudinal beams, the horizontal bridge direction is at regular intervals. An I-beam distribution beam is set up on which a full house support is installed, the lower end of each vertical rod of the full house support is supported on the upper flange plate of the I-beam distribution beam, and a cast-in-place box beam is installed on the top of the full house support. Template system. 2. The combined cast-in-situ box girder support system according to claim 1 is characterized in that: the load-bearing beam erected on the upper hoop is a truss structure, the upper chord is supported on the top of the upper hoop, and the lower chord is located on the upper and lower hoop. Between the support rod between the hoops and the outer wall of the pier, the upper chord and the lower chord are welded by diagonal bracing; the load-bearing beam erected on the top of the steel pipe column is a single-bar structure, and its specification and model are the same as the upper chord of the truss-type load-bearing beam erected on the upper hoop. Rods are consistent. 3. a method that adopts the combined cast-in-place box girder support system of claim 1 to carry out construction, is characterized in that comprising the steps: (1) Prepare the hoop, load-bearing beam, distribution beam, and steel pipe column according to the size of the bridge pier; assemble the Bailey longitudinal beam into a whole on the ground, and fix the reinforcing chord on the lower chord of the Bailey longitudinal beam through matching bolts; (2) Use lifting equipment to install and fix the upper hoop and the lower hoop on the mid-span pier column according to the design position, install the lower hoop first, and then install the upper hoop; (3) Construct the concrete expansion foundation on the bottom side of the side pier. After the concrete strength reaches the specification requirements, use the lifting equipment to hoist the steel pipe column on the side pier expansion foundation, and install the corresponding reinforcing structural accessories; (4) A truss-type load-bearing beam is installed on the upper hoop of the middle pier of the transverse bridge, and a support rod is installed between the corbels of the upper and lower hoop, and the lower chord of the truss-type load-bearing beam is limited between the support rod and the outer wall of the pier body; (5) Use lifting equipment to hoist the Bailey longitudinal beams along the bridge on the load-bearing beams of each span, and install corresponding reinforcement components; (6) Lay profiled steel distribution beams on the Bailey longitudinal beams according to the design requirements, and install corresponding reinforcement components; (7) A full hall support is erected on the profile steel distribution beam; (8) Set up a formwork system on the full hall support according to the design requirements; (9) After the preloading of the support meets the requirements of the specification, the cast-in-place box girder construction shall be carried out; when the concrete on both sides of the middle pier is poured, the unbalanced weight on both sides shall be controlled so as not to exceed the bearing capacity of the pier column itself; (10) After the concrete strength of the cast-in-place box girder reaches the specification requirements or the prestressed tension is completed, the entire support is removed.

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