Construction method for unbalanced beam section of continuous beam

Abstract

The invention provides a construction method for an unbalanced beam section of a continuous beam, and belongs to the field of building construction. According to the technical scheme, the construction method comprises the following steps that S1, firstly, balance weight construction is conducted on an unbalanced beam section of the continuous beam, and a jack is adopted to conduct tensioning balance weight on a previous side span beam section before pouring; and S2, concrete pouring construction is conducted, and the tensioning balance weight value of the jack is adjusted according to the concrete pouring amount in the pouring process. The method has the beneficial effects that the method is suitable for a balance mode under different construction working condition loads, and safety risks and potential quality hazards existing in a traditional unbalanced continuous beam balance weight mode are avoided.

Description

Technical Field

[0001] The present invention relates to the field of building construction, and in particular to a construction method of an unbalanced beam section of a continuous beam. Background Art

[0002] When constructing unbalanced sections of continuous beams, counterweights must be placed on the side of the sections with smaller spans and lighter weight. There are various methods for counterweight construction, generally using precast concrete blocks, water tanks, steel bars, counterpressure, etc. Traditional counterweight methods consume a lot of manpower, material resources, and financial resources, and there are safety risks in lifting. They are subject to different construction conditions. As the construction loads continue to change, they are prone to causing overloading of the beam body and cracks in the beam body, affecting the linear control of the continuous beam and posing construction safety hazards. Summary of the Invention

[0003] The purpose of the present invention is to provide a balancing method suitable for different construction conditions and loads, and to solve the safety risks and quality risks of the traditional unbalanced continuous beam counterweight method for the construction method of the unbalanced beam section of the continuous beam.

[0004] The present invention is achieved by the following measures: A construction method for an unbalanced beam section of a continuous beam, characterized in that the construction method comprises the following steps: S1. First, the unbalanced beam section of the continuous beam is counterweighted. The side span beam section of the previous section is tensioned and counterweighted using a jack before pouring. S2, concrete pouring construction, during the pouring process, adjust the jack tensioning weight value according to the concrete pouring amount; Preferably, a matching hydraulic station can be provided to adjust the tensioning counterweight value of the jack.

[0005] The specific features of the present invention also include: The formula for tensioning the counterweight by the jack in step S2 is: Q*L1+F2*L2=F3*L3+G*L4; Among them, Q is the tensioning counterweight value of the jack in the previous segment; L1 is the distance between the center of gravity of the tensioning counterweight position and the center of gravity of the pier; F2 is the resultant force of the side span beam section; L2 is the distance between the center of gravity of the side span beam and the center of gravity of the pier; F3 is the resultant force of the mid-span beam section; G is the real-time change value of the side span concrete; L4 is the distance between the center of gravity of the side span concrete and the center of gravity of the pier; Among them, F2 and F3 can be calculated based on the amount of concrete poured; The counterweight construction in step S1 includes the following steps: (1) During the construction of the foundation, the fine-rolled threaded steel bars are embedded in advance, the anchoring depth of the fine-rolled threaded steel bars is calculated, and the fine-rolled threaded steel bars are embedded in place. Double-jointed I-beams, fine-rolled threaded steel nuts and matching steel pads are installed on the top of the bars, and the bars are used as shoulder beams after installation; (2) During the construction of the side span beam section, the prestressed steel strands are passed vertically through the continuous beam. The prestressed steel strands are isolated from the beam body by metal bellows for easy disassembly. Double I-beams and matching steel pads, anchor pads, anchors, and tensioning jacks are installed on the top surface of the beam to increase the contact area with the beam body and prevent damage to the beam body. (3) The prestressed steel strands are firmly connected to the shoulder beams through anchor plates and anchors. The pedestal and the lower pile foundation provide ground anchors for the counterweight pull of the side span beam section, providing sufficient anchoring force to make the anchoring structure safe and stable.

[0006] The anchorage depth of the fine-rolled rebar is calculated by performing finite element analysis on the unbalanced continuous beam construction section, simulating the size of the unbalanced bending moment caused by the concrete pouring of the unbalanced beam section, and calculating it according to 1.5 times the maximum bending moment.

[0007] Before pouring concrete, anchors, jacks, and anchor pads are installed, and the jacks are tensioned to pre-tighten the prestressed steel tendons. As the concrete of the unbalanced beam section continues to be poured, the prestressed steel tendons always provide tension to resist the unbalanced bending moment, allowing the continuous beam to maintain a balanced state. Professional technicians monitor the entire process to ensure that the bridge piers and the entire beam body are not overloaded.

[0008] The prestressed steel strands are 3 in a single row and are composed of 18 φs15.2mm steel strands.

[0009] The shoulder pole beam is made of double-jointed I20a I-beam, and a single shoulder pole beam is 3m long.

[0010] The foundation is pre-buried with double rows of high-quality rolled threaded steel bars, 6 pieces in each row.

[0011] The embedded fine-rolled threaded steel and double-pieced I20a I-beam are connected using fine-rolled threaded steel nuts and matching steel plates.

[0012] The beneficial effects of the present invention are as follows: the present invention is applicable to a balancing method under different construction working conditions and loads, and solves the safety risks and quality hidden dangers of the traditional unbalanced continuous beam counterweight method. The continuous beam is in a dynamic equilibrium state, avoiding additional bending moment at the beam-column node and ensuring structural safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the structure of the present invention analysis.

[0014] Figure 2 It is a structural schematic diagram of the present invention.

[0015] Among them, the accompanying drawings are marked as: 1. Jack; 2. Hydraulic station; 3. Anchor; 4. Steel plate; 5. Anchor plate; 6. Metal bellows; 7. Cap; 9. Finished rolled threaded steel; 10. Finished rolled threaded steel nut; 11. Prestressed steel bundle; 13. I-beam. DETAILED DESCRIPTION

[0016] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0017] See also Figure 1 and 2 A method for constructing an unbalanced beam section of a continuous beam comprises the following steps: S1. First, the unbalanced beam section of the continuous beam is counterweighted. Jack 1 is used to tension and counterweight the side span beam section of the previous section before pouring. S2, concrete pouring construction, during the pouring process, adjust the tensioning weight value of jack 1 according to the pouring amount of concrete; Preferably, a matching hydraulic station 2 can be provided to adjust the tensioning counterweight value of the jack 1 .

[0018] The formula for tensioning the counterweight by jack 1 in step S2 is: Q*L1+F2*L2=F3*L3+G*L4; Where Q is the tensioning counterweight value of jack 1 in the previous segment; L1 is the distance between the center of gravity of the tensioning counterweight position and the center of gravity of the pier; F2 is the resultant force of the side span beam section; L2 is the distance between the center of gravity of the side span beam and the center of gravity of the pier; F3 is the resultant force of the mid-span beam section; G is the real-time change value of the side span concrete; L4 is the distance between the center of gravity of the side span concrete and the center of gravity of the pier; Among them, F2 and F3 can be calculated based on the amount of concrete poured; The counterweight construction in step S1 includes the following steps: (1) During the construction of the foundation, the fine-rolled threaded steel bars are embedded in advance, the anchoring depth of the fine-rolled threaded steel bars is calculated, and the fine-rolled threaded steel bars are embedded in place. The double-jointed I-beam 13, the fine-rolled threaded steel nut 10 and the matching steel plate 4 are installed on the top of the steel bar, and the steel bar is used as a shoulder beam after installation; (2) During the construction of the side span beam section, the prestressed steel strand 11 is passed vertically through the continuous beam. The prestressed steel strand 11 is isolated from the beam body by the metal bellows 6 for easy disassembly. The double-jointed I-beam 13 and the matching steel pad 4, anchor pad 5, anchor 3, and tensioning jack 1 are installed on the top surface of the beam to increase the contact area with the beam body and prevent damage to the beam body. (3) The prestressed steel strand 11 is firmly connected to the shoulder beam through the anchor plate 5 and the anchor 3. The pedestal 7 and the lower pile foundation provide the ground anchor for the counterweight downward tension of the side span beam section, providing sufficient anchoring force to make the anchoring structure safe and stable.

[0019] The anchorage depth of the fine-rolled threaded steel bar 9 is calculated by performing finite element analysis on the unbalanced continuous beam construction section, simulating the magnitude of the unbalanced bending moment caused by the concrete pouring of the unbalanced beam section, and calculating it according to 1.5 times the maximum bending moment.

[0020] Before pouring concrete, the anchor 3, jack 1, and anchor pad 5 are installed, and jack 1 is tensioned to pre-tighten the prestressed steel strands 11. As the concrete of the unbalanced beam section continues to be poured, the prestressed steel strands 11 always provide tension to resist the unbalanced bending moment, allowing the continuous beam to maintain a balanced state. Professional technicians monitor the entire process to ensure that the bridge piers and the entire beam body are not overloaded.

[0021] There are three prestressed steel strands 11 in a single row, and the prestressed steel strands 11 are composed of 18 φs15.2mm steel strands.

[0022] The shoulder pole beam is made of double-jointed I20a I-steel 13, and the length of a single shoulder pole beam is 3m.

[0023] The foundation 7 is pre-buried with double rows of finely rolled threaded steel bars 9 and 6 in a single row.

[0024] The embedded fine-rolled threaded steel bar 9 and the double-pieced I20a I-beam 13 are connected by fine-rolled threaded steel nut 10 and matching steel plate 4 for installation.

[0025] Technical features not described in the present invention can be achieved through or by adopting existing technologies and will not be described in detail here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A method for constructing an unbalanced beam section of a continuous beam, characterized in that: The construction method comprises the following steps: S1. First, the unbalanced beam section of the continuous beam is counterweighted, and the side span beam section of the previous section is tensioned and counterweighted by a jack before pouring; S2. During concrete pouring construction, the tensioning weight value of the jack is adjusted according to the amount of concrete poured.

2. The construction method of the unbalanced beam section of a continuous beam according to claim 1, characterized in that: The calculation formula of the jack tensioning counterweight value in step S2 is: Q*L1+F2*L2=F3*L3+G*L4; Among them, Q is the tension weight value of the jack; L1 is the distance between the center of gravity of the tensioning counterweight position and the center of gravity of the pier; F2 is the resultant force of the side span beam section; L2 is the distance between the center of gravity of the side span beam and the center of gravity of the pier; F3 is the resultant force of the middle span beam section; G is the real-time change value of the side span concrete; L4 is the distance between the center of gravity of the side span concrete and the center of gravity of the pier.

3. The construction method of the unbalanced beam section of a continuous beam according to claim 1, characterized in that: The counterweight construction in step S1 includes the following steps: (1) During the construction of the cap, the fine-rolled threaded steel is embedded in advance, the anchoring depth of the fine-rolled threaded steel is calculated, and the fine-rolled threaded steel is embedded in place. Double-piece I-beams, fine-rolled threaded steel nuts and matching steel pads are installed on the top of the steel cap, and the steel cap is used as a shoulder beam after installation; (2) During the construction of the side span beam section, the prestressed steel strands are passed vertically through the continuous beam. The prestressed steel strands are isolated from the beam body by metal corrugated pipes. Double-jointed I-beams and matching steel pads, anchor pads, anchors, and tensioning jacks are installed on the top surface of the beam. (3) The prestressed steel strands are securely connected to the shoulder beams through anchor plates and anchors. The pedestals and lower pile foundations provide ground anchors for the counterweight downward tension of the side span beam sections.

4. The construction method of the unbalanced beam section of a continuous beam according to claim 3, characterized in that: The anchorage depth of the fine-rolled rebar is calculated by performing finite element analysis on the unbalanced continuous beam construction section, simulating the size of the unbalanced bending moment caused by the pouring of concrete in the unbalanced beam section, and calculating it according to 1.5 times the maximum bending moment.

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