WO2021053696A2 - Poutre d'acier à précontrainte à section transversale variable - Google Patents

Poutre d'acier à précontrainte à section transversale variable Download PDF

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Publication number
WO2021053696A2
WO2021053696A2 PCT/IR2020/050030 IR2020050030W WO2021053696A2 WO 2021053696 A2 WO2021053696 A2 WO 2021053696A2 IR 2020050030 W IR2020050030 W IR 2020050030W WO 2021053696 A2 WO2021053696 A2 WO 2021053696A2
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WO
WIPO (PCT)
Prior art keywords
internal
steel
structures
supports
sectional area
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Application number
PCT/IR2020/050030
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English (en)
Inventor
Saeid KHOSROWJERDI
Original Assignee
Khosrowjerdi Saeid
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Khosrowjerdi Saeid filed Critical Khosrowjerdi Saeid
Publication of WO2021053696A2 publication Critical patent/WO2021053696A2/fr

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  • the purpose of the present invention is to increase the flexural capacity of steel beams by applying pre-stress, and creating variable cross-sectional area along the beam through the use of elements.
  • Pre-stressing steel structures through heating in this method, steel strands subjected to heat are used. One end of the heated strand is first welded to the bottom flange of the steel beam (because the bottom flange is usually under stress). Then, the length of the strand is increased through heating. Then, the other end of the strand is welded to the bottom flange of the steel beam. The cooling of the strand creates stress on the bottom flange.
  • the external pre-stressing is implemented.
  • Beams are one of the fundamental elements used in construction structures.
  • the primary function of steel beams is to control and resist the tensions resulting from shear forces and flexural moment caused by various applied loads to the structure.
  • the important factor taken into account in the design of steel beams is usually the flexural moment.
  • the flexural moment prevents engineers from designing structures with a wide span in that for wider spans, the size of section gets so huge that the construction of the structure with those dimensions seems not feasible on economic or architectural grounds.
  • the nature of flexural moment does not allow the maximum use of steel all over the span. More specifically, where there is observed the maximum flexural moment, the beam gets to the fracture point while in other points, the beam does not get to the yield point. Therefore, the huge part of steel capacity seems to be useless.
  • the primary purpose of the present invention is to maximize the steel use efficiency in flexural elements, and increasing the span of beams to a feasible size.
  • pre-stressing method is used in a beam with variable cross-sectional area so that one can use maximum steel efficiency, and the span size can be maximized without the need for increasing the beam dimensions.
  • This invention consists of the parts below:
  • the main element which can have different sections, like, hollow sections or I-shaped section
  • the stretch steel strands serve the function of applying pre-stress onto the main element.
  • the stretch steel strands move through a series of holes which are provided in the internal support along the beam considering the amount of, and the location of flexural moment applied as shown in figure 1.
  • the necessary camber can be determined using embedded holes in the internal supports, independently from the pre-stress applied.
  • the internal planes which serve to support the main element against flexural moment applied can be fixed into the keyway created in the internal support along the beam based on the needed cross sectional area as shown in figures 2 and 3.
  • the whole of this assembly is fitted into the main element with the strands connected to the external supports as shown in figures 4 and 5.
  • the external supports are welded to the two ends of the main element as shown in figure 6.
  • the stretch steel strands are put under tension. Based on the magnitude of the pre-stress applied and Beam dimensions, one, two, or more parallel stretch steel strands can be used for the beam as shown in figure 7.
  • the created pre-stress causes a negative camber in the beam as can be seen in figure 8, the magnitude of which can be regulated by the way stretch steel strands move through the holes provided in the internal support, and the magnitude of pre-stress applied. Moreover, positioning the internal supports at regular intervals along the main element can create a consistent camber. Because the camber created is proportionate to the dead load applied to the structure, it prevents the potential for buckling. Based on the flexural moment applied to the beam, and the necessary cross-sectional area, the internal planes with variable cross sectional areas can be distributed along the beam. The variable distribution of cross-sectional area maximizes the capacity of steel used. Pre-stressing rather than welding is used as a technique to connect the support planes to the main element in hollow sections. Figure 9 shows the construction diagram of the structure.
  • This invention leads to a higher efficiency and the use of maximal capacity of steel used along the main element.
  • This invention makes the designing of longer beams with suitable dimensions possible.
  • number 101 is the stretch steel strands
  • number 102 is the internal supports
  • number 103 is the internal planes fitted onto internal supports.
  • FIG. 1 shows the internal supports along with their components to be connected to the stretch steel strands and the internal planes.
  • number 105 is the connection place of internal planes.
  • Number 106 is the holes through which stretch steel strand(s) move.

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Abstract

Le facteur de détermination dans la conception de poutres est le plus souvent le moment de flexion. Dans la conception de structures, les ingénieurs sont limités, lors de la planification de structures à travée large, du fait que dans ces structures, le moment de flexion devient si grand qu'il rend pratiquement impossible la construction de telles structures. De plus, la nature du moment de flexion ne permet pas l'utilisation de la capacité totale de l'acier utilisé le long de la travée. Dans de telles structures, au niveau du point où le moment de flexion maximal est ressenti, la poutre atteint le point de fracture, tandis qu'au niveau des autres points le long de la poutre, elle n'atteint pas même la limite d'élasticité. Par conséquent, une grande partie de la capacité de l'acier mis en œuvre reste inutile dans la pratique. L'objet principal de la présente invention est d'améliorer l'efficacité de la capacité de l'acier utilisé dans des éléments de flexion, et d'augmenter la taille de la travée à des dimensions possibles.
PCT/IR2020/050030 2019-09-17 2020-09-08 Poutre d'acier à précontrainte à section transversale variable WO2021053696A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IR139850140003005416 2019-09-17
IR13983005400 2019-09-17

Publications (1)

Publication Number Publication Date
WO2021053696A2 true WO2021053696A2 (fr) 2021-03-25

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ID=74884738

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IR2020/050030 WO2021053696A2 (fr) 2019-09-17 2020-09-08 Poutre d'acier à précontrainte à section transversale variable

Country Status (1)

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WO (1) WO2021053696A2 (fr)

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