CN217268348U - Hybrid prestressed composite beam - Google Patents
Hybrid prestressed composite beam Download PDFInfo
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- CN217268348U CN217268348U CN202220398717.6U CN202220398717U CN217268348U CN 217268348 U CN217268348 U CN 217268348U CN 202220398717 U CN202220398717 U CN 202220398717U CN 217268348 U CN217268348 U CN 217268348U
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Abstract
A hybrid prestressed composite beam comprises a prefabricated composite beam part and a cast-in-place concrete part, wherein the prefabricated composite beam part comprises lower section steel and prefabricated concrete poured on the lower section steel; stretching a mid-span prestressed tendon in the precast concrete, wherein the mid-span prestressed tendon extends into the cast-in-place concrete; and the lower section steels of the adjacent prefabricated combination beams are connected and have a distance, and the cast-in-place concrete is poured above the lower section steels and between the adjacent prefabricated combination beams. Compare with traditional prestressing force shaped steel concrete structure, the utility model has the characteristics of rigidity is big, and the prestressing force degree is high, and economic benefits is showing, and the construction is convenient etc, applys prestressing force to support hogging moment district concrete simultaneously, makes the structure have higher normal use and durability.
Description
Technical Field
The utility model belongs to the technical field of the building, in particular to mixed prestressing force combination roof beam.
Background
The steel reinforced concrete structure has good bearing capacity and rigidity, and is widely applied to a large-span heavy-load structure, but the crack resistance performance of the steel reinforced concrete structure is general, and the tunnel researchers put forward the prestressed steel reinforced concrete structure, but the prestressing force of the existing steel reinforced concrete is mainly provided by prestressed tendons, the attainable prestressing force degree is limited, the prestressing force loss is serious, the tension process control is strict, and the phenomena of inverted arch cracking and the like are easy to occur. If the single pre-bent beam pre-stress construction method is adopted, the load is directly applied to the profile steel without the help of auxiliary profile steel, the problems of overlarge deflection, small effective pre-pressing area and the like caused by the fact that the single profile steel is small in rigidity can be solved, the concrete prefabrication rate is limited, and the field construction amount is increased.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects of the prior art, the utility model aims to provide a hybrid prestressed composite beam, the final prestress of which is provided by the profile steel and the prestressed tendons together, wherein in the application process of the prestress of the profile steel, the lower profile steel and the auxiliary profile steel are combined to form a composite steel beam, so that a higher neutral axis position is obtained, the whole section of the lower profile steel is pulled, the area of a pre-pressing area is larger, the prefabrication rate is higher, and the purpose of reducing the field construction amount is achieved. Because the whole section of the prefabricated combined beam is pressed, the prestressed tendons are more flexibly arranged, and the phenomenon of inverted arch cracking generated when the prestressed tendons are tensioned is easily solved. The utility model discloses a prestressing tendons extends to support upper portion to adopt unbonded prestressing force construction technology, reach at the concrete and set for after the intensity through stretch-draw prestressing tendons once more, make support department concrete produce pre-compaction stress equally, with this crack resistance who improves the structure.
In order to realize the purpose, the utility model discloses a technical scheme be:
the utility model provides a mix prestressing force combination beam, includes prefabricated combination beam and cast in situ concrete, prefabricated combination beam includes lower part shaped steel and pours in the precast concrete of lower part shaped steel, stretch-draw span prestressing tendons among the precast concrete, the lower part shaped steel of adjacent prefabricated combination beam is connected and has the interval, cast in situ concrete pours in lower part shaped steel top and between the adjacent prefabricated combination beam, span prestressing tendons extension stretches into in the cast in situ concrete.
In one embodiment, the precast concrete is cast under the lower flange of the lower section steel, the lower portion of the web, and the lower flange, and the cast-in-place concrete is cast over the upper flange of the lower section steel, the upper portion of the web, and the upper flange.
In one embodiment, the lower section steel is fixed at two ends by an anchorage device after the deformation of the lower section steel is recovered.
In one embodiment, a groove is formed in the cast-in-place concrete above the upper flange of the lower section steel, the extension portion of the mid-span prestressed tendon is a support prestressed tendon, and the end portion of the support prestressed tendon is fixed in the groove through a second anchorage device.
Compared with the prior art, the beneficial effects of the utility model are that:
1. the benefits are remarkable
Compared with the traditional prestressed steel reinforced concrete beam, the utility model discloses under the prerequisite that material cost does not increase, only through changing construction method at the prefabrication stage, exert the pre-bending load to the combination girder steel earlier, utilize the elastic shrinkage of combination girder steel to exert first prestressing force to the concrete, then utilize the effect of prestressing tendons to exert second prestressing force to the concrete; compared with the method of only relying on the prestressed tendons to provide the prestress, the prestress of the utility model is provided by the profile steel and the prestressed tendons together, the prestress effect is greatly improved, the number of the prestressed tendons is reduced, and the labor cost is greatly reduced while the material cost is saved; in addition, the higher rigidity of the prefabricated combined beam part can greatly reduce the number of supports in site construction, and the economic benefit is obvious.
2. Reasonable stress
The utility model discloses first stage prestressing force is provided by the restoring force of shaped steel, because first stage prestressing force needs to apply the preflex load to the shaped steel, precast concrete reaches certain intensity uninstallation back, shaped steel receives precast concrete's constraint effect, can not resume initial state, still there is the residual deflection deformation, the residual deflection deformation that first stage pre-compaction load brought is offset in the anti-arch effect that produces through stretch-draw prestressing tendons this moment, make shaped steel resume initial geometric state, the later stage "roof beam-roof beam" of being convenient for is connected, "roof beam-post" connection installation.
3. The performance is excellent
The utility model discloses owing to receive the effect of dual prestressing force, it possesses higher rigidity and bearing capacity, and the fracture load is higher, and the elasticity scope is wider, and prestressing tendons can extend to support hogging moment district in addition, treats that cast in situ concrete reaches and sets for intensity after, stretch-draw prestressing tendons can make support department concrete obtain prestressing force equally, has improved the normal use and the durability of structure. The utility model discloses a mix prestressing force combination beam, compare and directly exert the load on lower part shaped steel, the too big problem of flexibility under this method can solve the effect of first-stage prestressing force reaches the effect of little amount of deflection high stress.
4. Construction is convenient
The construction method adopted by the utility model improves the position of the neutralization shaft of the combined steel beam, the lower section steel can be completely positioned in the compression area, the area of the effective prepressing area is increased, the concrete prefabrication rate is improved, and the field construction amount is reduced; meanwhile, the on-site installation method of the utility model is simple and convenient for construction, and after the section steel is spliced, the concrete at the joint is poured together with the concrete at the upper part of the section steel; the support prestressed tendons adopt unbonded prestressed force, and after the cast-in-place concrete reaches the set strength, the support prestressed tendons can be tensioned and installed partially. For the double-arch combination mode, as the tensioning of the prestressed reinforcing steel bars is not needed, the construction process is simpler, and the construction speed is higher.
Drawings
Fig. 1 is a schematic diagram of the construction process of the double-line combined mode of the present invention.
FIG. 2 is a schematic view of the construction process of the utility model with big top and small bottom.
Fig. 3 is a schematic diagram of the construction process of the double arch type combination mode of the present invention.
Fig. 4 is a schematic view of the connection relationship of the parts of the present invention.
Fig. 5 is a schematic view of the connection of the hogging moment area prestressed tendons of the present invention.
The reference numerals explain:
a lower section steel 1; auxiliary section steel 2; prefabricating concrete 3; a midspan prestressed tendon 4; an anchorage device I5; casting concrete 6 in situ; a groove 7; a support prestressed tendon 8; and a second anchorage device 9.
Detailed Description
The following describes embodiments of the present invention in detail with reference to the accompanying drawings and examples.
Referring to fig. 1 to 5, the utility model discloses a mixed prestressed composite beam includes prefabricated composite beam and cast in situ concrete 6, and prefabricated composite beam mainly includes lower part shaped steel 1 and pours in the precast concrete 3 of lower part shaped steel 1, and stretch-draw has the prestressing tendons 4 of striding in among the precast concrete 3, and the lower part shaped steel 1 of adjacent prefabricated composite beam just has the interval at end connection. The cast-in-place concrete 6 is poured above the lower section steel 1 and between the adjacent prefabricated composite beams, the midspan prestressed tendons 4 are extended and extend into the cast-in-place concrete 6, and the end parts of the prestressed tendons are fixed.
In the structure, the midspan prestressed tendons 4 are stretched from two ends of the precast concrete 3 in a pre-bending state of the lower section steel 1, and are fixed at two ends of the lower section steel 1 by the first anchors 5 after the lower section steel 1 is deformed and recovered.
The utility model discloses in, to stride the extension definition of well prestressed tendons 4 for support prestressed tendons 8, the top that cast in situ concrete 6 is located the top flange of lower part shaped steel 1 is provided with recess 7, and support prestressed tendons 8 stretch-draw in cast in situ concrete 6, and its tip is fixed with ground tackle two 9 in recess 7.
The utility model discloses mixed prestressing force composite beam's construction method, including prefabricated part construction and site operation, wherein prefabricated part construction mainly is the prefabricated composite beam of preparation, and site operation is mainly connected each prefabricated composite beam as an organic whole.
As shown in fig. 1, the preparation of the prefabricated composite girder includes the steps of:
s1) combining the auxiliary section steel 2 with the lower section steel 1 to obtain a combined steel beam.
For example, the auxiliary section steel 2 and the lower section steel 1 may be stacked up and down (flanges are horizontal, and webs are vertical) and then fixed by using shear bolts or the like to form a composite steel beam.
In this embodiment, the auxiliary section steel 2 has the same cross section as the lower section steel 1, and a double-straight combination type combined steel beam is obtained.
S2) applying a downward vertical load to pre-bend the combined steel beam.
Illustratively, a vertical load can be applied to the upper part of the auxiliary section steel 2 to cause the combined steel beam to generate deflection, wherein the vertical load is large enough to ensure that only the elastic deformation of the lower section steel 1 and the auxiliary section steel 2 occurs. And, after the vertical load is removed, the deformation of the auxiliary section steel 2 can be completely recovered, and the permanent auxiliary member can be used repeatedly.
S3) pouring precast concrete 3 into the lower section steel 1.
Illustratively, after the combined steel beam is pre-bent by applying a vertical load to the combined steel beam and reaches a set deflection, pouring the precast concrete 3, and performing steam curing after the pouring is finished, wherein the precast concrete 3 can be made of ultra-high performance concrete.
The precast concrete 3 can be poured on the lower flange of the lower section steel 1, the lower part of the web plate and the lower part of the lower flange.
S4) unloading and removing the auxiliary section steel 2.
Illustratively, the precast concrete 3 is unloaded after reaching the set strength, and the auxiliary section steel 2 is removed after the unloading is finished.
S5) stretching the span prestressed tendons 4 in the precast concrete 3 to obtain the precast combined beam.
Illustratively, the span prestressed tendon 4 is constructed by adopting a prestressed steel strand and a post-tensioning method, during construction, tensioning is carried out from two ends, and after the deformation of the lower section steel 1 is completely recovered, two ends of the span prestressed tendon 4 are fixed outside the precast concrete 3 by using an anchorage device I5.
Optionally, the utility model discloses a combination girder steel still can be for big-end-up small-size compound mode or two arch form compound modes.
Specifically, as shown in fig. 2, when the combination of the upper and lower parts is adopted, the sectional height of the lower section steel 1 is higher than that of the auxiliary section steel 2, and the construction process is completely the same as that of the double straight line type combination.
As shown in fig. 3, when the double arch type combination mode is adopted, the lower section steel 1 and the auxiliary section steel 2 are both arch type, the flange parts can be perfectly attached, and bolt holes are matched with each other; during construction, the upper arch disappears under the action of a pre-bending load, the combined steel beam becomes a linear type, then the precast concrete 3 is poured, and the span prestressed tendons 4 are not stretched, so that the obtained final form is an arch shape.
As shown in fig. 4 and 5, during on-site construction, the lower section steel 1 of the adjacent prefabricated composite beam is connected, then the cast-in-place concrete 6 is poured, after the cast-in-place concrete 6 reaches a set strength, the support prestressed tendons 8 are tensioned in the cast-in-place concrete, and the anchor devices 9 are used for anchoring.
In the figure N p1 And N p2 Respectively representing primary prestressing and secondary prestressing. The first-stage prestress is provided by the restoring force of the section steel and is the compressive stress generated on the concrete by the shrinkage of the section steel after unloading; the second-stage prestress is provided by the prestressed tendons and can be divided into two parts, wherein one part is applied in the preparation stage of the prefabricated composite beam, and the other part is applied after the cast-in-place concrete 6 reaches the designed strength.
The cast-in-place concrete 6 can be cast on the upper flange of the lower section steel 1, the upper part of the web plate and above the upper flange.
Specifically, a groove 7 is reserved in the cast-in-place concrete 6 to anchor the support prestressed tendons 8 by a second installation anchorage device 9, and the groove 7 is filled with concrete after anchoring is completed.
Claims (4)
1. The utility model provides a hybrid prestressed composite beam, characterized in that, includes prefabricated composite beam and cast-in-place concrete (6), prefabricated composite beam includes lower part shaped steel (1) and pours precast concrete (3) in lower part shaped steel (1), stretch-draw span prestressing tendons (4) in precast concrete (3), lower part shaped steel (1) of adjacent prefabricated composite beam are connected and have the interval, cast-in-place concrete (6) are pour in lower part shaped steel (1) top and between the adjacent prefabricated composite beam, span prestressing tendons (4) extension stretch into in the cast-in-place concrete (6).
2. The hybrid prestressed composite girder according to claim 1, wherein the precast concrete (3) is cast under the lower flange, the lower portion of the web, and the lower flange of the lower section steel (1), and the cast-in-place concrete (6) is cast over the upper flange, the upper portion of the web, and the upper flange of the lower section steel (1).
3. The hybrid prestressed composite girder according to claim 1, wherein the span prestressed tendon (4) is tensioned from both ends in a state where the lower section steel (1) is pre-bent, and is fixed at both ends thereof by the anchor (5) after the deformation recovery of the lower section steel (1).
4. The hybrid prestressed composite girder according to claim 1, wherein the cast-in-place concrete (6) is provided with a groove (7) above the upper flange of the lower section steel (1), the extension of the mid-span tendon (4) is a support tendon (8), and the end of the support tendon (8) is fixed in the groove (7) by a second anchorage (9).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220398717.6U CN217268348U (en) | 2022-02-25 | 2022-02-25 | Hybrid prestressed composite beam |
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| CN202220398717.6U CN217268348U (en) | 2022-02-25 | 2022-02-25 | Hybrid prestressed composite beam |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114412189A (en) * | 2022-02-25 | 2022-04-29 | 西安建筑科技大学 | Combined steel beam prestress construction method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114412189A (en) * | 2022-02-25 | 2022-04-29 | 西安建筑科技大学 | Combined steel beam prestress construction method |
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