KR100691848B1 - Continuous PS Concrete Composite Girder Reinforcement Method by Additional Tensioning Material Settled on Branch Floor - Google Patents

Abstract

This method is intended to reinforce the point deck where cracks can be generated due to the connection between the internal points of the PS composite girder and the external load generated by the continuous load. To this end, install the fixing end reinforcement plate fixed at both ends of the point bottom plate together with the bottom plate reinforcing bars, and the ducts and tension members installed in the manufacturing stage of the continuous PS concrete girder for the additional tension, are placed and installed inside the point bottom plate. Connect to the anchorage opposite the point. When the floorboard is cast and cured, tension is applied to the additional tension material and settled. As the additional tensioning material of this method is fixed at the end of the point bottom plate, it is easy to introduce tension and fixation work, and the loss of friction can be considerably reduced than the case of introducing friction between the two points of the inner point. . In particular, it is possible to minimize the secondary reaction force or the secondary moment generated in the continuous girder by controlling the deflection of the static moment caused by the additional tension in the point bottom section.

PS concrete, composite girder, bridge, continuity, bottom plate, additional tension, fixing end reinforcement plate

Description

Structuring method of Continuous Prestressed Concrete Composite Girder by Anchoring Additional Tendon on Support-Slab}

[Figure 1] Bending moment distribution diagram by load and primary tension of existing PS concrete girder

(a) Bending moment distribution map due to loads acting on simple mounted girders

(b) Equivalent Load and Bending Moment Distribution Diagram for Primary Tension

(c) Bending moment distribution diagram by additional load acting on continuous composite girders

[Figure 2] Bending moment distribution diagram by the additional tension of continuous PS concrete composite girder

(d) Bending moment distribution chart due to tension of additional tension member arranged in girder

(e) Bending moment distribution map due to tension of additional tension member extending to the bottom plate

(f) Bending moment distribution map due to tension of additional tension member settled at point deck

3 is a construction process diagram of the continuous PS concrete composite girder by the present method

(1) Assembly of reinforcing end reinforcement plate, primary tension member and additional tension member

(2) PS concrete girder fabrication and primary tension

(3) PS concrete girder mounting and internal point continuity

(4) Cross beam installation, reinforcing bar reinforcement of point plate, installation of additional tension material and anchorage

(5) Branch bottom plate placement and curing, introduction of additional tension, reinforcing bar reinforcement of middle floor plate

(6) middle plate placement and curing

4 is an arrangement detail of the additional tension member fixed to the end of the branch bottom plate of the present method

5 is a perspective view of the point bottom plate of the composite concrete girder PS according to the present method

<Description of Symbols for Main Parts of Drawings>

10. Support floor slab

11. Point bottom plate Fusing end reinforcement plate (channel or angle)

12. Additional tensioning anchorage 13. Reinforcing bars of point bottom plate

14. Middle-slab 15. Reinforcing bars of the middle plate

16. Introduced additional tension in the outer span 17. Introduced additional tension in the inner span

20. Medial pier 21. PS concrete girder 22. Slab

23. Cross-beams 24. Chair units

25. Outer PS concrete girder 26. Introduce primary tension of outer PS concrete girder

27. Inner PS concrete girder 28. Introduce primary tension of inner PS concrete girder

30. Arrangement of outer PS concrete girder rebar and fixing end reinforcement plate

31. Outer PS concrete girder primary tension and duct

32. Addition of external PS concrete girder

33. Arrangement of inner PS concrete girder rebar and fixing end reinforcement plate

34. Inner PS concrete girder primary tension and duct

35.Addition of inner PS concrete girder

36. Rebar in PS Concrete Girder

37.PS concrete girder fixing end reinforcement plate (application number 10-2004-0009282 or 10-2004-0017706)

38. Internal point continuous connection plate

41. Loads on simple mounted girders

42. Bending moment due to the load of simple mounted girders

43. Equivalent Load for Primary Tension

44. Bending moment due to primary tension

45. Additional loads acting on continuous composite girders

46. Bending moment due to additional load of continuous composite girder

51. Equivalent Load for Additional Tension of Continuous Composite Girder

52. Secondary reaction force at internal point due to additional tension introduced in continuous composite girders

53. Bending Moment due to Additional Tension of Continuous Composite Girder

54. Bending moment due to secondary reaction forces at internal points

55. Bending Moment due to Additional Tension and Secondary Reaction Force of Continuous Composite Girder

56. Location of anchorages of additional tension members in the point bottom plate

In PS (prestressed) concrete composite girder bridges, PS concrete girders are usually simply mounted on the stabilization device as shown in Fig. 1 (a), but simple supported girders use expansion joints at relatively large cross sections and points, and poor ride comfort. Because of such problems, many continuous chemical processes have been developed. Such methods include the attachment of tensioned carbon fibers to the top of the girder (domestic application 20-2003-0040349) or the use of steel crossbeams (domestic application 20-2003-0026137) and the rise and fall of branches (domestic application 10-1998-0001799) and weights. Various methods have been attempted, such as the use of (Domestic Application 10-1998-0000421). However, these joints have the disadvantage of easily cracking at the joints due to the discontinuity of the material.In order to solve these problems, external tension members forcibly introducing compressive stress to the joints (domestic application 20-2003-0014875, 10-2001-0060681, 10-2001-0036273, 10-2000-0067723) and additional tensioning materials (domestic application 10-2004-0024800) extending from the parental section to the bottom plate may be applied.

The additional load of the sequential composite girders generates parental portions at the internal points as shown in Fig. 1 (c), which causes cracks in the support-slab (10). It can be suppressed by the method of introducing tension (domestic application 10-1999-0019658, 10-1999-0043513). However, when the parent tension due to the additional tension force is introduced into the continuous composite girder, the secondary reaction force 52 acting downward from the inner point as shown in Fig. 2 (d) to resist the camber of the girder. ) Occurs. The moment due to the secondary reaction force 52 is called the secondary moment 54 for the case where both ends of the continuous girders are simply supported, and the secondary moment is introduced to resist the static moment caused by the external load between the spans. The parental tension 53 due to the reduced tension is reduced as shown in FIG. 2, and in particular, serious reduction is caused in the reduction of the parental force introduced into the inner span.

The secondary reaction force 52 due to the additional tension force introduced in the direction opposite to the external load in the continuous composite girder decreases as the deflection of the static moment introduced by the additional tension force to the inner point as shown in FIG. 2 increases. The secondary reaction force and the secondary moment can be reduced to some extent as shown in FIG. 2 (e) by the method of the additional tensioning material (domestic application 10-2004-0024800) extending from the PS concrete composite girder to the bottom plate. In order to control the secondary reaction force, it is necessary to reduce the parent moment due to the additional tension introduced between the spans. However, the reduction of the parent moment due to the additional tension between spans also reduces the resistance against static moments due to external loads, so a more efficient secondary reaction or secondary moment control method is required. This method is to control the size and section of the static moment introduced by the additional tension at the inner point of the continuous PS concrete composite girder as shown in Figure 2 (f) to solve these problems.

The connection of the internal points of the continuous PS concrete girder may cause cracks due to material discontinuities, and additional loads after continuity may cause cracks in the point deck. To solve this problem, the additional tension introduced in the continuous composite girder generates a secondary reaction force and its secondary moment at the internal point. Therefore, the following problems must be solved for the continuous PS concrete composite girder.

1. Stabilization of continuous connections at internal points

2. Crack control of spot deck at the site

3. Control of secondary reaction force or secondary moment by additional tension force introduced into continuous PS concrete composite girder

4. Easiness of fixation of additional tension material against additional tension introduced in PS concrete composite girder

This method is to solve various problems that may occur after the sequencing by the general method of the simple mounted PS concrete girder as shown in Fig. 3 (3). PS concrete girder (25,27) between the outer span and the inner span is manufactured as shown in Figure 3 (2) in a state where the ducts 32 and 35 for additional tensioning material are installed in advance as shown in Figure 3 (1), Tension is introduced into the primary tensioning material (26, 28) before mounting on (24). PS concrete girder is mounted on the bridge device of the piers as shown in Fig. 3 (3) and is continuous in a general manner and the middle crossbeam 23 is installed.

End reinforcement plate 11 in which the fixing device 12 of the additional tension member is fixed to the end of the point bottom plate 10 defined as the bottom plate of the parent moment region between the inflection points where the direction of the bending moment is changed by the external load. ) Is installed near the inflection point, and the ducts and tension members (32,35) for the additional tension (16, 17) are installed together with the reinforcing bars (13, 15) of the bottom plate as shown in Figs. . When the bottom plate 10 concrete is poured and cured, additional stress is introduced (16, 17) as shown in FIG. 3 (5) or FIG. The anchorages at both ends of the point deck are for tensioning and anchoring the additional tension member installed in the opposite girder and the additional tension is introduced in the span unit on both sides of the internal point. When additional tension is introduced, the middle floor concrete between the point bottom plates is cast and cured as shown in FIG. 3 (6) or FIG. 5.

When the tension of the additional tension force introduced into the continuous PS concrete composite girder is settled at the end of the point deck as in the present method, the following effects can be expected.

1. The compressive stress of the internal point connection due to the additional tension that is introduced after the PS concrete girder is continually suppressed the cracking caused by the discontinuity of the material in the connection can ensure the stable behavior of the connection.

2. The introduction of compressive stress due to additional tension in the point deck placed in the parent section near the internal point due to the additional load acting on the continuous PS concrete composite girder can suppress the cracking of the point deck.

3. Since the additional tension member is settled at the end of the bottom plate, sufficient working space can be secured for introducing tension force, and the tension member is easy to settle.

4. The positive moment deflection caused by the additional tension near the internal point is determined by the anchoring position of the additional tension member. The deflection due to the constant moment reduces the rising of the parent moment caused by the additional tension between the spans. You can control the secondary reaction force or the secondary moment at the point.

5. Since the additional tension is introduced in both span units based on the internal point, it is possible to reduce the loss of tension due to friction than when the additional tension is introduced in the entire span.

Claims (1)

1) Reinforcement reinforcement (36) of the PS concrete girder is reinforced, and inside the reinforcement reinforcement (36) of the PS concrete girder and the primary tension and duct (31, 34) and the additional tension and duct (32, 35) to form an arch Is installed so that the middle portion of the concave, the additional tension member and the ducts (32, 35) is located on top of the primary tension member and the ducts (31, 34) and at the same time additional tension member mounting holes of other adjacent PS concrete girder (21) Assembling to extend up to 12; 2) manufacturing the PS concrete girder 21 such that primary tensions 26 and 28 are introduced into the primary tensioning material and the ducts 31 and 34; 3) mounting each of the PS concrete girder 21 prepared in accordance with the step 2) to the bridge device 24, and sequentially mounting the mounted PS concrete girder 21, and installing the intermediate crossbeam 23; 4) Install an additional tension member mounting hole 12 at the point where the moment is inflected from the point bottom plate 10 of the PS concrete girder 21 continuous in accordance with step 3), and reinforces the point bottom plate 10 Connecting the additional tension member and the ducts (32, 35) to the additional tension member mounting holes (12) installed on the point bottom plate (10) opposite the internal points, respectively, after the reinforcing bars (13); 5) pouring concrete into the point bottom plate (10) and curing; 6) introducing the additional tension members and the ducts 32 and 35 into the additional tension member mounting holes 12 connected thereto after introducing the additional tension forces 16 and 17 into the additional tension members and the ducts 32 and 35; And 7) reinforcing the reinforcing bar (15) to the middle bottom plate (14), and curing after pouring concrete; Reinforcement method of the continuous PS concrete composite girder, characterized in that comprises a.

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