CN210561680U - Pretensioned ultra-high performance concrete composite beam - Google Patents
Pretensioned ultra-high performance concrete composite beam Download PDFInfo
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- CN210561680U CN210561680U CN201921206331.5U CN201921206331U CN210561680U CN 210561680 U CN210561680 U CN 210561680U CN 201921206331 U CN201921206331 U CN 201921206331U CN 210561680 U CN210561680 U CN 210561680U
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Abstract
The utility model discloses a pretensioning method ultra high performance concrete composite beam, including being located the compression district on composite beam upper portion, and be located the tension district of composite beam lower part. The tension area is made of ultra-high performance concrete, and a plurality of parallel prestressed tendons are arranged inside the tension area in a pretensioning way; the stress direction of each prestressed tendon is parallel to the tension direction borne by the tension area; the compression zone is made of common concrete and is fixed with the tension zone by reserved steel bars arranged in the tension zone. The utility model discloses make full use of the characteristics that ultra high performance concrete compressive strength is high, avoided the not closely knit defect of post-tensioned method pipeline grout, reduced the size of component, realized the light-dutyization of ultra high performance concrete component.
Description
Technical Field
The utility model relates to a combination beam structural design technical field, in particular to pretension method ultra high performance concrete combination beam.
Background
The ultra-high performance concrete (namely UHPC material) is different from the traditional high-strength concrete and steel fiber concrete, is not the high reinforcement of the traditional meaning 'high performance concrete', is a new variety of cement-based structural engineering material with definite performance indexes, and has the characteristics of ultra-high strength, ultra-high toughness, ultra-high durability and the like. The ultra-high performance concrete is applied to structural engineering, so that the structure can be lightened, and the service life of the structure can be prolonged.
Because the manufacturing cost of the ultra-high performance concrete is higher, the structural form of combining the ultra-high performance concrete and the common concrete is an ideal application mode, namely, the ultra-high performance concrete is adopted in a tension area, and the common concrete is adopted in a compression area, so that the stronger tensile property of the ultra-high performance concrete is fully utilized.
For example, the publication number CN108118610A discloses an ultra-high performance concrete and ordinary reinforced concrete composite beam, which includes a UHPC prefabricated main beam and a post-cast ordinary reinforced concrete bridge deck, the UHPC main beam is prefabricated in advance, a shear connector is preset on the top of the UHPC prefabricated beam, the UHPC prefabricated beam serves as a construction platform after being installed in place, ordinary concrete is poured after a steel mesh is arranged on the top edge of the UHPC prefabricated beam, and the UHPC prefabricated beam top shear connectors are combined to form the composite beam. The combined beam is formed by combining ultra-high performance concrete and common reinforced concrete, and emphasizes that a main beam is prefabricated by adopting UHPC materials, a top plate is erected to serve as a construction platform, and a concrete bridge deck is poured; however, this simple combination does not actually take full advantage of and exploit the properties of UHPC materials.
In the case of ultra-high performance concrete, although it has ultra-high strength, its compressive strength is much greater than its tensile strength. Generally, the compressive strength of the ultra-high performance concrete can reach more than 120MPa, but the axial tensile strength is only about 7-10MPa, which is greatly improved compared with the common concrete, but is greatly different from the steel.
In structural application, even if a combined structural form is adopted, the tensile strength is always close to the tensile design strength value in the limit state, but the compressive strength is far less than the compressive design strength value, namely the compressive strength is far from being utilized insufficiently, and the material performance is not fully exerted.
In practical application, the prior art generally adopts post-tensioning method to utilize the characteristics of UHPC material, and the UHPC prefabricated post-tensioning composite beam has the following defects:
1. the UHPC prefabricated post-tensioned composite beam needs to pre-embed a corrugated pipe and use an anchorage device to stretch a stress beam, and the anchorage device and the corrugated pipe are provided with minimum size requirements, so that the reduction of the size of a main beam is limited, the waste of materials is caused, and the self weight is increased;
2. the UHPC prefabricated post-tensioned composite beam needs to stretch a prestressed tendon after the beam body material reaches the designed strength, grouting the pipeline after the prestressed tendon is stretched, and releasing the tension after the slurry of the pipeline reaches the strength; therefore, the construction process is relatively complex, and the construction time is obviously prolonged;
3. the problem of incompact grouting is easily caused in the grouting process due to the narrow corrugated pipe;
4. after the UHPC prefabricated post-tensioned composite beam forms a composite structure, the prestressed steel bundles are tensioned, and the compression resistance and the tensile resistance of the ultra-high performance concrete cannot be fully exerted; during the process of tensioning the prestressed steel bundles, the common concrete of the top plate may crack when the tensioning stress is too large.
Therefore, how to combine the ultra-high performance concrete with the prestressing technology in the structural design to fully utilize the compression resistance of the ultra-high performance concrete is a technical problem to be solved in the field.
SUMMERY OF THE UTILITY MODEL
In view of the above-mentioned defect of prior art, the utility model provides a pretensioning ultra high performance concrete composite beam, the purpose of realization utilize characteristics such as the superhigh intensity that has, ultra high toughness and ultra high durability of UHPC material, combine the pretensioning more effective ultra high performance concrete and the combined use of prestressing force technique, make to use ultra high performance concrete to have higher compressive stress deposit for the composite beam of material.
In order to achieve the above object, the present invention discloses a pretensioned ultra high performance concrete composite beam, which comprises a compression zone located on the upper portion of the composite beam and made of ultra high performance concrete, and a tension zone located on the lower portion of the composite beam and made of general concrete.
Wherein, a plurality of parallel prestressed tendons are arranged in the tension area by a pretensioning method;
and the stress direction of each prestressed tendon is parallel to the tension direction borne by the tension area.
When the tension zone is prefabricated, a reserved steel bar is reserved at the connecting position of the tension zone and the compression zone; the compression zone and the tension zone are fixed by reserved steel bars.
Preferably, the prestressed tendons are steel strand wires, stress-relief steel wires, prestressed twisted steel bars or FRP tendons.
Preferably, the composite beam is a box beam, and the compression zone is a cover plate part positioned on the top surface of the box beam;
the cross section of the tension area is of a groove-shaped strip structure with an opening at the upper part;
and a width below the tension zone is less than a width of the cover portion.
Preferably, the combined beam is a channel beam, and the compression zones are parts of two side walls of the channel beam close to the upper end;
the cross section of the tension area is of a groove-shaped strip structure with an opening at the upper part.
More preferably, reinforcing steel bars are arranged in the compression zone.
More preferably, the compression zones are post-tensioned to set compression zone stress bundles.
The utility model has the advantages that:
the utility model discloses building and combining the use with the ultra high performance concrete by the pretensioning prestressing tendons with the prefab, setting up the prestressing tendons with the ultra high performance concrete and adopting the pretensioning at the tension district, utilized the high characteristics of ultra high performance concrete compressive strength, set up a great prestressing force at the tension district, improve the load-carrying capacity who pulls the district.
The utility model discloses compare with current post-tensioned method construction technique, removed arranging of ground tackle and prestressed pipe from, avoided the not closely knit defect of post-tensioned method pipeline grout, the construction steps of reduction have improved the efficiency of construction.
The utility model discloses reduced the holistic size of composite beam, really realized the light-dutyization of ultra high performance concrete member, more had economic nature.
The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings, so as to fully understand the objects, the features and the effects of the present invention.
Drawings
Fig. 1 shows a schematic structural view of a box beam according to an embodiment of the present invention.
Fig. 2 shows a schematic view of a trough beam according to an embodiment of the present invention.
Fig. 3 is a schematic view showing a state in which a tension portion of a box beam is completed according to an embodiment of the present invention.
Detailed Description
Examples
As shown in fig. 1 and 2, the pretensioned ultra high performance concrete composite beam includes a compression zone 3 made of ultra high performance concrete at an upper portion of the composite beam, and a tension zone 2 made of general concrete at a lower portion of the composite beam.
Wherein, a plurality of parallel prestressed tendons 1 are arranged in the tension area 2 by a pretensioning method; and the stress direction of each prestress beam 1 is parallel to the tension direction carried by the tension area.
The principle of the utility model lies in that, divide into the compression district 3 on upper portion and the tension district 2 two parts of lower part with combination beam itself, tension district sets up a plurality of prestressing tendons 1 with ultra high performance concrete and adoption pretension method, applys a great prestressing force, makes it have higher compressive stress deposit, and the compression district is made for ordinary concrete.
When the tension zone 2 is prefabricated, a reserved steel bar 4 is reserved at the connecting position of the tension zone 2 and the compression zone 3; the compression zone 3 and the tension zone 2 are fixed by reserved steel bars.
The pre-stressed tendons 1 are generally made of steel strands, stress-relief steel wires, pre-stressed twisted steel bars or FRP tendons.
In certain embodiments, as shown in fig. 1, the composite beams are box beams and the compression zone 3 is a deck section located on the top face of the box beam.
The cross section of the tension area 2 is of a groove-shaped strip structure with an opening above the tension area 1.
And the width below the tension zone 2 is smaller than the width of the cover part.
In some embodiments, as shown in fig. 2, the composite beam is a channel beam, and the compression zones 3 are portions of both side walls of the channel beam near the upper end.
The cross section of the tension area 2 is of a groove-shaped strip structure with an opening above the tension area 1.
In some embodiments, reinforcing steel is arranged in the tension zone 2.
In some embodiments, the tension zone 2 places the compression zone stress beams in a post-tensioning manner.
As shown in fig. 1 and 3, the utility model discloses still provide the construction method of pretensioning ultra-high performance concrete composite beam, the step is as follows:
A. installing a template on a pre-tensioning method pedestal, and tensioning a plurality of prestressed tendons 1;
B. pouring the tension area 2 by adopting ultra-high performance concrete, and reserving a reserved steel bar 4 for connecting with the compression area 3 during pouring;
C. maintaining, when the strength of the tension area 2 reaches the design strength, shearing all the prestressed tendons 1;
D. removing the pedestal of the tension area 2 applied with prestress, and installing a template to pour a compression area 3;
E. curing until the pressed area 3 reaches the designed strength.
Compared with the prior art, after the technology of the utility model is applied, the following remarkable progress is achieved:
1. in the utility model, a plurality of prestressed tendons are directly arranged in a tension area by a pretensioning method, so that an anchorage device is not needed to be additionally added, a corrugated pipeline is not needed to be reserved, the cost is saved, and the size of the structural section can be greatly reduced;
2. the composite beam applying the technology of the utility model can be released as long as the beam body material reaches the design strength, grouting is not needed, the grouting flow is saved, and the manufacturing time is also saved; compared with the post-tensioning method in the prior art, the construction is rapid and convenient, and the efficiency is higher;
3. the composite beam applying the technology of the utility model does not need grouting, and eliminates the problem of incompact grouting of post-tensioning method components;
4. the composite beam applying the technology of the utility model pours the tension area of the UHPC under the state of prestress tension, carries out prestress steel beam tension release after the UHPC part reaches the strength, and finally pours the common concrete part; by the operation, the prestress effect can be completely applied to the UHPC part, the compression resistance and the tensile resistance of the UHPC can be fully exerted, and the problem that common concrete cracks when post-tensioning prestress steel beams are tensioned in the prior art is solved.
The foregoing has described in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions that can be obtained by a person skilled in the art through logic analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection defined by the claims.
Claims (6)
1. The pretensioning ultra-high performance concrete composite beam comprises a compression zone (3) positioned at the upper part of the composite beam and a tension zone (2) positioned at the lower part of the composite beam; the method is characterized in that:
the tension area (2) is made of ultra-high performance concrete, and a plurality of parallel prestressed tendons (1) are arranged in the tension area by a pretensioning method;
the stress direction of each prestressed tendon (1) is parallel to the tension direction borne by the tension area (2);
the compression zone (3) is made of common concrete and is fixed with the tension zone (2) by a reserved steel bar (4) arranged in the tension zone (2).
2. The pretensioned ultra high performance concrete composite beam of claim 1, wherein the composite beam is a box beam, the compression zone (3) being a deck portion located on a top face of the box beam; the cross section of the tension area (2) is of a groove-shaped strip structure with an opening at the upper part; and the width below the tension zone (2) is smaller than the width of the cover part.
3. The pretensioned ultra high performance concrete composite beam of claim 1, wherein the composite beam is a channel beam, and the compression zones (3) are portions of both side walls of the channel beam near the upper end; the cross section of the tension area (2) is of a groove-shaped strip structure with an opening at the upper part.
4. The pretensioned ultra high performance concrete composite beam of any one of claims 1 to 3, wherein the pre-stressed tendons (1) are steel strands, stress-relief steel wires, pre-stressed twisted steel bars, or FRP tendons.
5. The pretensioned ultra high performance concrete composite beam of claim 1, wherein a reinforcing steel bar is disposed in the compression zone (3).
6. Pretensioned ultra high performance concrete composite beam according to claim 5, characterized in that the compression zone (3) is post-tensioned with compression zone stress beams.
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| CN201921206331.5U CN210561680U (en) | 2019-07-29 | 2019-07-29 | Pretensioned ultra-high performance concrete composite beam |
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| CN201921206331.5U CN210561680U (en) | 2019-07-29 | 2019-07-29 | Pretensioned ultra-high performance concrete composite beam |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110295538A (en) * | 2019-07-29 | 2019-10-01 | 上海市城市建设设计研究总院（集团）有限公司 | Pre-tensioning system ultra-high performance concrete combination beam and its construction method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110295538A (en) * | 2019-07-29 | 2019-10-01 | 上海市城市建设设计研究总院（集团）有限公司 | Pre-tensioning system ultra-high performance concrete combination beam and its construction method |
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