CN220433380U - Post-tensioned prestressing T-shaped beam - Google Patents
Post-tensioned prestressing T-shaped beam Download PDFInfo
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- CN220433380U CN220433380U CN202320680435.XU CN202320680435U CN220433380U CN 220433380 U CN220433380 U CN 220433380U CN 202320680435 U CN202320680435 U CN 202320680435U CN 220433380 U CN220433380 U CN 220433380U
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- 238000004873 anchoring Methods 0.000 claims abstract description 49
- 230000002787 reinforcement Effects 0.000 claims abstract description 44
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 41
- 239000010959 steel Substances 0.000 claims abstract description 41
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims abstract description 30
- 239000004567 concrete Substances 0.000 claims abstract description 11
- 238000004901 spalling Methods 0.000 claims abstract description 7
- 238000012423 maintenance Methods 0.000 abstract description 4
- 238000005452 bending Methods 0.000 abstract description 2
- 230000002035 prolonged effect Effects 0.000 abstract description 2
- 239000002344 surface layer Substances 0.000 abstract description 2
- 239000010410 layer Substances 0.000 description 12
- 238000013461 design Methods 0.000 description 8
- 238000004364 calculation method Methods 0.000 description 6
- 230000003014 reinforcing effect Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 239000011513 prestressed concrete Substances 0.000 description 4
- 238000007906 compression Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 239000011150 reinforced concrete Substances 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000013178 mathematical model Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 210000002435 tendon Anatomy 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
Abstract
The utility model discloses a post-tensioned pre-stress T-shaped beam, which comprises a pre-stress steel beam anchored on the T-shaped beam, the T-shaped beam end prestressed steel beam anchoring end concrete is internally provided with a stripped reinforcing steel bar encryption area and a split reinforcing steel bar encryption area from outside to inside; the encryption area of the stripped steel bars is arranged in the range of 3 cm-h/8, and in the encryption area of the stripped steel bars, according to the shape of the anchoring end face of the beam end, bending the surface layer steel bars into a form corresponding to the anchoring end for blanking, and arranging vertical closed steel bars inwards; the splitting reinforcement encryption area is arranged within the range of h/8-3 h/4 from the anchoring end, the hooping adopts a vertical closed steel bar. The utility model has the advantages that: the beam end of the prestress T-shaped beam is provided with a spalling reinforcement encryption area and a splitting reinforcement encryption area, the number and the length of cracks near the anchoring end after tensioning are effectively controlled, the safety and the durability of the prestress component are protected, the service life is prolonged, and further the later maintenance cost is reduced.
Description
Technical Field
The utility model relates to the technical field of concrete support members, in particular to a post-tensioned pre-stress T-shaped beam.
Background
The concrete structure of a concrete bridge is generally divided into zones B and D, zone B referring to the area conforming to the plain assumption, letter B representing bernoulli's assumption (Bernoulliassumption) or a pure curved Beam (Beam). The region D refers to the stress disturbance region, the letter D represents a discontinuous or Disturbed portion (Discontinuity). In prestressed beams, the prestressed anchorage zone is typically the D zone, and the anchorage forces not only create strong local pressure on the concrete under the anchorage, but also create spalling forces at the edges of the beam ends.
He Zhiqi and the like define the magnitude of the splitting force generated by the anchoring force in the anchoring area by the elastic stress and main stress trace method, and establish a tension-compression bar model according to the main stress trace method to determine the magnitude of the splitting force in the anchoring area. And the Zhao construction is based on a common prestress anchoring area tension-compression bar model, and the tension-compression bar model is researched and corrected to determine the magnitude of the splitting force. Aiming at the problem that the post-tensioned prestressing anchoring area of the thin web concrete box girder cracks along the direction of the prestressing tendons, the American scholars Stone and Brien develop extensive analysis and experimental research, and know that the splitting tensile stress is positioned on a load axis and vertical to a loading axis, and the peeling tensile stress is positioned on or near a loading surface and parallel to the loading surface. He Zhiqi develops a force flow mathematical model of the D region, deduces a tension effect simplified calculation formula, and realizes quantitative calculation of the splitting force and splitting stress calculation of the anchoring region at the end part of the flat plate. Hong Hao the problem of spatial diffusion of the end anchoring forces is studied, and a three-dimensional force streamline mathematical model and a three-dimensional main compressive stress trace of the end anchoring region are proposed. As shown in fig. 1, these forces typically create three types of cracks in the anchoring zone, namely a cleavage crack, a spalling crack and a vertical tearing crack.
For the splitting cracks and the vertical cracks, the current 'design specification of reinforced concrete and prestressed concrete bridge and culvert of highway' provides corresponding calculation formulas and control methods for the safety checking and calculation of local bearing of an anchoring area and the section size of a concrete member. For horizontal stripping cracks, the calculation formula of the peripheral stripping force caused by local collapse of an anchor backing plate is given in the design specification of reinforced concrete and prestressed concrete bridges and culverts of the highway: t (T) s,d ＝
0.02max{P di In the formula, P di The design value of the ith anchoring force on the same end face is designed. When the center distance of the two anchoring forces is larger than 1/2 of the section height of the anchoring end, the magnitude of the stripping force generated by the end surface between the large-spacing anchor heads is calculated according to the following formula:wherein P is d And S is the center distance of two anchoring forces, and h is the section height of the anchoring end.
For the stripping cracks generated by the anchoring force, the third section 9.4.18 of the current 'highway reinforced concrete and prestressed concrete bridge and culvert design Specification' indicates that 'the beam end section should be provided with anti-cracking reinforcing steel bars for resisting the surface stripping force', but no specific arrangement form is given. Therefore, it is important to reasonably arrange the reinforcing steel bars at the prestress anchoring end to control the stripping cracks.
Disclosure of Invention
The utility model aims to provide a post-tensioned pre-stressed T-shaped beam, which fully considers a splitting crack, a stripping crack and a vertical tearing crack.
In order to achieve the above purpose, the present utility model is realized by the following technical scheme:
a post-tensioned prestressing T-shaped beam comprises a prestressing steel beam anchored on the T-shaped beam, wherein a spalling reinforcement encryption area and a splitting reinforcement encryption area are arranged in concrete at the anchoring end of the prestressing steel beam at the beam end of the T-shaped beam from outside to inside; the splitting reinforcement encryption area is arranged in the range of 3 cm-h/8, and in the splitting reinforcement encryption area, surface reinforcement is bent into a form corresponding to an anchoring end according to the shape of the anchoring end surface of the beam end, and is subjected to blanking, and is bound with web reinforcements and erection reinforcement of the beam into a whole, vertical closed reinforcement is also arranged inwards, and is bound with the web reinforcements and erection reinforcement of the beam into a whole; the splitting reinforcement encryption area is arranged within the range of h/8-3 h/4 from the anchoring end, and the stirrups are vertically closed in the splitting reinforcement encryption area.
Further, the diameter of the reinforcing steel bar in the stripped reinforcing steel bar encryption area is 6-8 mm.
Further, the reinforcing steel bars of the stripped reinforcing steel bar encryption area are at least arranged in four layers, wherein the at least four layers comprise more than or equal to two layers of truncated reinforcing steel bars according to the shape of the anchoring end face of the beam end.
Further, the vertical closed steel bars of the stripped steel bar encryption area are three layers.
Further, the distance between the outermost layer of reinforcing steel bars of the stripped reinforcing steel bar encryption area and the end face of the anchoring end is 30mm, and the spacing between the reinforcing steel bars of other layers is 40-50 mm.
Further, the diameter of the stirrup in the splitting reinforcement encryption area is 12-16 mm.
Further, the stirrup spacing of the splitting reinforcement encryption area is 100mm.
Compared with the prior art, the utility model has the following advantages:
the post-tensioned pre-stress T-shaped beam improves the safety and durability of the structure, reduces the maintenance cost of the post-tensioned pre-stress T-shaped beam and prolongs the service life of the bridge. Specifically, a spalling reinforcement encryption area is arranged under a beam end anchor of the post-tensioned prestressing T-shaped member, so that the occurrence and the expansion of cracks are effectively reduced, the safety and the durability of the structure are greatly improved, meanwhile, the method is simple and easy to understand, and the later maintenance and repair cost is reduced; on the basis of the original design, the beam end stripping reinforcing steel bar encryption area is added for reinforcing bars, the reinforcing bars in the original splitting reinforcing steel bar encryption area are not changed, the change is relatively small, the design construction is simplified, and the budget is saved; the beam end anchoring reinforcement encryption area is further divided into an anchoring broken reinforcement encryption area and an anchoring broken reinforcement encryption area according to the occurrence of cracks, the distance between the broken reinforcement encryption area and the anchoring broken reinforcement encryption area is small, and thin reinforcements are adopted; the original design of the spacing and the diameter of the reinforcing steel bars is adopted in the splitting reinforcing steel bar encryption area, so that the reinforcing steel bar arrangement method according to the stress area is more reasonable, and is easy to understand and master by design staff; the steel bars in the spalling reinforcement encryption area under Liang Duanmao are in various reinforcement forms and are arranged in parallel along the anchoring section, so that the cracking stress of the prestress anchoring end is effectively prevented from generating cracks, the crack development is controlled, and the shape of the section of the end is adapted.
Drawings
FIG. 1 is a schematic illustration of three exemplary cracks in an end anchor zone of prestressed concrete.
Fig. 2 is a schematic view of an arrangement of prior art anchor end rebar.
Fig. 3 is a schematic cross-sectional view of the rebar arrangement of fig. 2.
Fig. 4 is a schematic view of the arrangement of the anchoring end reinforcing bars of the present utility model with the stripped reinforcing bar encryption zone and the split reinforcing bar encryption zone.
Fig. 5 is a schematic cross-sectional view of a rebar placement of the spalled rebar encryption under anchor of section 1-1 of fig. 4.
Fig. 6 is a schematic cross-sectional view of a rebar placement of the under-anchor split rebar encryption area of section 2-2 of fig. 4.
Fig. 7 is a schematic diagram of a reinforcing bar according to the present utility model.
Detailed Description
Embodiments of the present utility model are described in further detail below with reference to the accompanying drawings.
As shown in fig. 4, in the post-tensioning prestressed T-shaped beam provided by the application, a stripped reinforcing steel bar encryption area and a split reinforcing steel bar encryption area are arranged at the beam end prestressed steel beam anchoring end of the prestressed T-shaped beam from outside to inside, and reinforcing steel bar encryption of the beam end anchoring area refers to encryption reinforcing steel bars which are formed by arranging bending thin reinforcing steel bars and straight reinforcing steel bars along the surface layer of the toothed anchoring end without changing other positions of the anchoring area. And the beam end is added to strip the reinforcing steel bar reinforcement so as to resist cracks generated by the stripping force, and the encrypted equidistant stirrups are still arranged in the splitting reinforcing steel bar encryption area.
As shown in fig. 4 and 5, in the stripped steel bar encryption area, at least four layers of stripped steel bars are arranged under the beam end anchors, wherein the stripped steel bars comprise more than or equal to two layers of truncated steel bars according to the shape of the anchoring end face of the beam end, as shown in the figures, the steel bars V1, S0, S1 and S2 from top to bottom are bent into a form corresponding to the anchoring end and are bound into a whole with web bars and erection steel bars of the beam. Meanwhile, a plurality of layers of vertical closed steel bars are further arranged inwards along the high-pass length of the beam, and the steel bars V0 shown in the drawing are preferably three layers, and are also bound with web bars and erection steel bars of the beam into a whole. The diameter of the steel bar in the stripped steel bar encryption area is 6-8 mm, the stripped steel bar encryption area under the anchor at the beam end is arranged in the range of 3 cm-h/8 (along the length direction of the beam), the distance between the outermost layer of steel bars and the end face of the anchor end is 30mm, and the distance between the steel bars of other layers is 40-50 mm.
As shown in fig. 4 and 6, in the splitting reinforcement encryption area, the hooping forms are vertical closed reinforcements, the interval of the hooping is 100mm, the diameter is 12-16 mm, and the arrangement area of the splitting reinforcements under the beam end anchors is in the range of h/8-3 h/4 (along the length direction of the beam) from the anchoring end.
According to the manufacturing method of the post-tensioned pre-stressing T-shaped beam, when the binding of the steel bars in the splitting steel bar encryption area and the splitting steel bar encryption area is completed, the pre-stressing beam is penetrated, the template is erected, and then the post-pouring concrete is poured. And (5) waiting for the concrete curing to finish , and stretching the prestressed steel bundles. The tensioning of the prestressed tendons is divided into four stages (25%, 50%,75% and 100%) and the four stages are tensioned to the anchor to control the stress. After the construction of the prestress component is completed, as the beam end of the prestress T-shaped beam is provided with the stripped reinforcing steel bar encryption area and the split reinforcing steel bar encryption area, the number and the length of cracks near the anchoring end after tensioning are effectively controlled, the safety and the durability of the prestress component are protected, the service life is prolonged, and further the later maintenance cost is reduced.
The foregoing is merely a preferred embodiment of the present utility model, and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the concept of the present utility model, and such modifications and adaptations are intended to be comprehended within the scope of the present utility model.
Claims (7)
1. A post-tensioned pre-stressed T-beam comprising a pre-stressed steel beam anchored to the T-beam, characterized in that: the T-shaped beam end prestressed steel beam anchoring end concrete is internally provided with a spalling reinforcement encryption area and a splitting reinforcement encryption area from outside to inside; the splitting reinforcement encryption area is arranged in the range of 3 cm-h/8, and in the splitting reinforcement encryption area, surface reinforcement is bent into a form corresponding to an anchoring end according to the shape of the anchoring end surface of the beam end, and is subjected to blanking, and is bound with web reinforcements and erection reinforcement of the beam into a whole, vertical closed reinforcement is also arranged inwards, and is bound with the web reinforcements and erection reinforcement of the beam into a whole; the splitting reinforcement encryption area is arranged within the range of h/8-3 h/4 from the anchoring end, and the stirrups are vertically closed in the splitting reinforcement encryption area.
2. A post-tensioned pre-stressed T-beam as recited in claim 1, wherein: the diameter of the steel bar in the stripped steel bar encryption area is 6-8 mm.
3. A post-tensioned pre-stressed T-beam as recited in claim 1, wherein: the steel bars of the stripped steel bar encryption area are at least arranged in four layers, wherein the stripped steel bars comprise more than or equal to two layers of truncated steel bars according to the shape of the anchoring end face of the beam end.
4. A post-tensioned pre-stressed T-beam as recited in claim 3 wherein: the vertical closed steel bars of the stripped steel bar encryption area are three layers.
5. A post-tensioned pre-stressed T-beam as recited in claim 4, wherein: the distance between the outermost layer of reinforcing steel bars of the stripped reinforcing steel bar encryption area and the end face of the anchoring end is 30mm, and the spacing between the reinforcing steel bars of other layers is 40-50 mm.
6. A post-tensioned pre-stressed T-beam as recited in claim 1, wherein: the diameter of stirrups in the splitting reinforcement encryption area is 12-16 mm.
7. A post-tensioned pre-stressed T-beam as recited in claim 6, wherein: and the stirrup spacing of the splitting reinforcement encryption area is 100mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320680435.XU CN220433380U (en) | 2023-03-27 | 2023-03-27 | Post-tensioned prestressing T-shaped beam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320680435.XU CN220433380U (en) | 2023-03-27 | 2023-03-27 | Post-tensioned prestressing T-shaped beam |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220433380U true CN220433380U (en) | 2024-02-02 |
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ID=89695423
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320680435.XU Active CN220433380U (en) | 2023-03-27 | 2023-03-27 | Post-tensioned prestressing T-shaped beam |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220433380U (en) |
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2023
- 2023-03-27 CN CN202320680435.XU patent/CN220433380U/en active Active
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