CN219993229U - Reinforcing structure of overground part of multi-layer brick building and indoor construction auxiliary device - Google Patents

Abstract

The utility model discloses a reinforcing structure of an overground part of a multi-layer brick building and an indoor construction auxiliary device, which comprise a plurality of groups of outer columns and inner columns for reinforcing bearing walls of the multi-layer building, and also comprise a plurality of groups of outer beams and inner beams for reinforcing floors and clinging to the bottom surfaces of the floors, wherein two ends of each group of outer beams and each group of inner beams are connected with the top ends of each group of outer columns and the top ends of each group of inner columns through nodes, and two ends of each group of inner beams and the top ends of each group of inner columns and each group of outer columns are covered outside all steel bars by ultra-high performance concrete and are filled with all operation holes inserted with third annular steel bars to form connecting nodes. The reinforced structure can form an ultra-high performance concrete reinforced beam connected with the upright post for the floor slab of any structure. The indoor construction auxiliary device occupies a relatively small indoor space during indoor reinforcement construction, does not need to remove a large amount of indoor furniture articles, and has relatively high construction efficiency.

Description

Reinforcing structure of overground part of multi-layer brick building and indoor construction auxiliary device

Technical Field

The utility model relates to the technical field of repairing of a non-frame-structure bricked dangerous old house, in particular to a reinforcing structure of an overground part of a multi-layer bricked building and an indoor construction auxiliary device.

Background

The overground part of the multi-layer brick building is generally formed by building a bearing wall by brick blocks and mortar and adding prefabricated floors. Because the building is not of a frame structure, the building time of the building is generally more than 40 years, the building is lost in years, the structural stability is poor, the building has no shock resistance basically, and even some building is in danger. The number of the buildings is huge, and the large-scale disassembly and reconstruction are difficult.

The inventor name of the utility model is that the reinforcement structure of overground part of the multi-layer masonry building is applied in advance, UHPC, ultra-high performance concrete and a plurality of steel bars are adopted to form a plurality of upright posts for reinforcing the multi-face bearing brick wall; and the prefabricated floor slab with the porous structure is reinforced by steel bars and ultra-high performance concrete.

Relatively, the reinforced structure is convenient for constructors, less in demolition and damage, small in influence on residents, small in increased size, relatively low in construction cost and firm and stable in structure.

However, the reinforcement structure can only be adapted to the prefabricated floor slab with the porous structure, and the reinforcement of the floor slab cannot be performed if the prefabricated floor slab with the porous structure is not used. In addition, the hall type scaffold is required to be fully constructed in the indoor construction of the living person, and the construction is floor-consuming, laborious and time-consuming.

Disclosure of Invention

The utility model aims to solve the technical problem of providing a reinforcing structure for the overground part of a multi-layer brick building, which can form an ultra-high performance concrete reinforcing beam connected with a stand column for a floor slab with any structure.

The technical scheme of the utility model is that the reinforcing structure of the overground part of the multi-layer brick building comprises a plurality of groups of outer upright posts and inner upright posts which are used for reinforcing the bearing wall of the multi-layer building, each group of outer upright posts and inner upright posts comprises a plurality of vertical steel bars and a plurality of first annular steel bars connected with the plurality of vertical steel bars, each first annular steel bar penetrates through an operation hole on the bearing wall, and each group of inner upright posts and outer upright posts is formed by coating the steel bars outside the section by ultra-high performance concrete and filling all operation holes inserted with the first annular steel bars;

the reinforcing structure of the overground part of the multi-layer brick building further comprises a plurality of groups of outer beams and inner beams which are used for reinforcing the floor and clinging to the bottom surface of the floor, each group of outer beams and inner beams comprises a plurality of transverse steel bars and a plurality of second annular steel bars connected with the plurality of transverse steel bars, each second annular steel bar penetrates through an operation hole on the bearing wall, and each group of inner beams and outer beams are formed by coating the steel bars outside the section by ultra-high performance concrete and filling all operation holes inserted with the second annular steel bars;

the two ends of each group of outer cross beams and inner cross beams are connected with the top ends of each group of outer stand columns and the top ends of the inner stand columns through nodes: the plurality of third annular steel bars connected with the plurality of vertical steel bars and penetrating through the respective operation holes are connected with the plurality of transverse steel bars of the outer cross beam through the plurality of first L-shaped steel bars and connected with the plurality of transverse steel bars of the inner cross beam through the plurality of second L-shaped steel bars, both ends of each group of inner cross beam and both ends of each group of inner and outer stand columns are coated with ultra-high performance concrete outside the steel bars in the section, and all the operation holes inserted with the third annular steel bars are filled to form connection nodes.

Compared with the prior art, the reinforcing structure of the overground part of the multi-layer brick building with the structure has the following advantages: in the reinforcement construction of the outer cross beam and the inner cross beam in each group of cross beams, only the synchronous construction or the cross construction with the reinforcement of the upright posts is needed, only the bottom surface of the floor slab of any floor slab structure is needed, the annular steel bars of the inner cross beam and the outer cross beam penetrate through the operation holes of the bearing wall below the floor slab and are filled with ultra-high-performance concrete, the support force of the reinforcement upright posts and the support force of the bearing wall below the floor slab are utilized, the direct connection relation with the floor slab is not needed, the ultra-high-performance concrete reinforcement cross beam connected with the upright posts and the bearing wall can be formed for the floor slab of any structure, the universality is strong, and the reinforcement structure of the ultra-high-performance concrete reinforcement cross beam connected with the upright posts can be formed for the overground part of the multi-layer brick building of the floor slab of any structure, and the application range is quite wide.

The reinforcing structure is convenient to construct, less in demolition and damage, small in influence on residents, small in size and relatively low in construction cost. And the mechanical properties of the bearing wall and the floor slab are enhanced to a great extent, and powerful support and protection are provided for the multi-layer brick building, so that the wall body lost repair for a long time is restored and even slightly exceeds the original bearing capacity, and the firm and stable house structure after repair is ensured.

Further, the inner and outer cross beams in the X direction and the inner and outer cross beams in the Y direction are connected with the inner and outer stand columns in the Y direction to form a frame structure. After the structure is adopted, the mechanical properties of the bearing wall and the floor slab are further enhanced, and further powerful support and protection are provided for the multi-layer brick building, so that the wall body lost in the past is restored and even slightly exceeds the original bearing capacity, and the firmness and the stability of the house structure after repair are further ensured.

The utility model aims to solve the other technical problem of providing the indoor construction auxiliary device of the reinforcing structure of the overground part of the multi-layer brick building, which occupies the indoor space as small as possible during indoor reinforcement construction, does not need to remove a large amount of indoor furniture articles and has relatively high construction efficiency.

The utility model provides an indoor construction auxiliary device of the reinforcing structure of the overground part of the multi-layer brick building, which comprises a U-shaped steel bar at each of two ends, wherein the U-shaped steel bar is connected with a first annular steel bar below the joint of a third annular steel bar and a second L-shaped steel bar, two free ends of each U-shaped steel bar pass through two through holes on a steel bracket vertical plate with an L-shaped top, and two nuts are respectively screwed on external threads at the two free ends of the U-shaped steel bar to fix the steel bracket; the L-shaped template for pouring the ultra-high performance concrete of the inner cross beam is detachably fixed in the L-shaped grooves of the L-shaped steel corbels at the two ends; the indoor construction frame with the crawling ladder, the construction platform and the plurality of rollers for indoor construction is further included.

After adopting above structure, the fixed bracket of reinforcing bar that the joint department of usable reinforced structure, and the L font template of indoor crossbeam then fixes in the L word inslot of steel bracket, makes the template simple structure of crossbeam to the original template of usable indoor stand, and the cat ladder and the construction platform that utilize movable indoor scaffold install or demolish the template and fix the reinforcing bar and pour the construction of the ultra-high performance concrete of indoor stand and crossbeam. The indoor construction auxiliary device of the reinforcing structure of the overground part of the multi-layer brick building is simple, stable and reliable in structure, occupies the indoor space as small as possible, namely relatively small, during indoor reinforcement construction, does not need to remove a large amount of indoor furniture articles, omits tedious construction for building and dismantling the hall-filling scaffold, and is relatively high in construction efficiency.

Further, the indoor construction auxiliary device of the reinforcing structure of the overground part of the multi-layer brick building further comprises a detachable support rod for supporting the middle of the length of the L-shaped template. After the structure is adopted, the stability and the reliability of the construction template are further guaranteed, the occupied indoor space is further guaranteed to be as small as possible during indoor reinforcement construction, a large amount of indoor furniture articles do not need to be removed, complicated construction for building and dismantling the hall-full scaffold is omitted, and the construction efficiency is relatively high.

Further, the top of the supporting rod is an L-shaped block for supporting the L-shaped template, a pair of ear plates are fixed at the bottom of the L-shaped block, a pair of hinge holes are formed in the ear plates, a hinge block is fixed at the top of the supporting rod body, a hinge hole is formed in the hinge block, and a hinge pin is inserted into the three hinge holes and is axially limited; the bracing piece body comprises three sections, and there is first screw hole the bottom of upper segment, and the middle section is the hexagon post that both ends are external screw thread, and there is the second screw thread on the top of hypomere, and the opposite direction of the external screw thread at hexagon post both ends, the opposite direction of the internal screw thread of first screw hole and second screw hole, the external screw thread at hexagon post both ends is closed in first screw hole and second screw thread soon, and the positive rotation is in order to prop the L font template or be contrary to rotate in order to break away from the top to prop. After the support rod adopts the specific structure, the hexagonal column can be rotated by using a wrench, so that the support rod is more convenient to mount or dismount and prop, and the stability and reliability of the construction template are further ensured.

Drawings

Fig. 1 is a schematic perspective view showing the application of the reinforcing structure of the present utility model to the overground part of a multi-layered brick-laid building.

Fig. 2 is a schematic structural view of the reinforcement structure of the present utility model showing the reinforcing bars of the inner and outer cross members and the reinforcing bars of the connection nodes (the outdoor portion is shown with emphasis).

Fig. 3 is an enlarged schematic view of the structure of fig. 2 a.

Fig. 4 is a schematic structural view showing the reinforcing bars of the inner and outer cross members and the reinforcing bars of the connection nodes of the indoor construction auxiliary device of the present utility model (the indoor portion is shown with emphasis; the U-shaped reinforcing bars and nuts are shown).

Fig. 5 is an enlarged schematic view of the structure of B in fig. 4.

Fig. 6 is a schematic view of the reinforcement structure and the indoor construction auxiliary device of the present utility model showing the structure of the reinforcing bars of the connection nodes (the indoor portion is shown with emphasis; the bracket is shown).

Fig. 7 is an enlarged schematic view of the structure of C in fig. 6.

Fig. 8 is a schematic structural view of the indoor construction auxiliary device of the present utility model.

Fig. 9 is an enlarged schematic view of the structure D in fig. 8 (hinge pin not shown).

Fig. 10 is an enlarged schematic view of the structure of E in fig. 8.

Fig. 11 is an enlarged schematic view of the structure of F in fig. 8.

The figure shows: 1. the second L-shaped steel bars, 2, floors, 3, outer columns, 4, inner columns, 5, bearing walls, 6, second annular steel bars, 7, transverse steel bars, 8, first annular steel bars, 9, third annular steel bars, 10, vertical steel bars, 11, first L-shaped steel bars, 12, operation holes, 13, external threads, 14, nuts, 15, U-shaped steel bars, 16, ultra-high performance concrete, 17, inner beams, 18, outer beams, 19, L-shaped grooves, 20, steel corbels, 21, support rods, 22, climbing ladders, 23, rollers, 24, indoor construction frames, 25, construction platforms, 26, L-shaped templates, 27, lower sections, 28, hexagonal columns, 29, upper sections, 30, L-shaped blocks, 31, hinge holes, 32, lug plates, 33, support rod bodies, 34, hinge blocks, 35, reinforcing rib plates, 36 and vertical plates.

Detailed Description

The following describes the embodiments of the present utility model further with reference to the drawings. It should be noted that the description of these embodiments is for aiding in understanding the present utility model, but is not to be construed as limiting the utility model. In addition, the technical features described in the following embodiments of the present utility model may be combined with each other as long as they do not collide with each other.

Ultra high performance concrete, UHPC (Ultra-High Performance Concrete), also known as reactive powder concrete (RPC, reactive Powder Concrete), has been the most innovative cement-based engineering material in the world over the last decades, especially over the last decade, and has achieved a large span of engineering material properties. Ultra-high performance concrete is a mature technology, the performances, the formula and the like are well described in the online encyclopedia, and the technical specification of on-site detection of the elastic modulus of structural concrete of related technical standards such as CBMF XX-201X is also published. The utility model does not improve the ultra-high performance concrete, but uses the ultra-high performance concrete to form the reinforced upright post and the reinforced cross beam.

As shown in fig. 1, 2, 3, 4, 5, 6, and 7.

The reinforcing structure of the overground part of the multi-layer brick building comprises a plurality of groups of outer columns 3 and inner columns 4 which are used for reinforcing the bearing walls 5 of the multi-layer building, and as can be seen from figure 1, each group of outer columns 3 and inner columns 4 can comprise a group of outer columns 3 with L-shaped cross sections and inner columns 4 with square cross sections. Or a group of outer columns 3 with rectangular or prolate square cross sections and inner columns 4 with rectangular or prolate square cross sections. Or a group of an outer column 3 with a rectangular cross section and two inner columns 4 with square cross sections. Each group of outer upright posts 3 and inner upright posts 4, namely the outer upright posts 3 and the inner upright posts 4 in each group of upright posts, comprise a plurality of vertical steel bars 10 and a plurality of first annular steel bars 8 connected with the plurality of vertical steel bars 10, each first annular steel bar 8 penetrates through an operation hole 12 on the bearing wall 5, and each group of inner and outer upright posts is formed by coating the steel bars, namely the vertical steel bars 10 and the first annular steel bars 8, with ultra-high-performance concrete 16 and filling all the operation holes 12 inserted into the first annular steel bars 8.

The utility model relates to a reinforcing structure of an overground part of a multi-layer brick building, which also comprises a plurality of groups of outer beams 18 and inner beams 17 used for reinforcing a floor slab 2 and clinging to the bottom surface of the floor slab 2, wherein each group of outer beams 18 and inner beams 17, namely, the outer beams 18 and the inner beams 17 in each group of beams, comprise a plurality of transverse steel bars 7 and a plurality of second annular steel bars 6 connected with the transverse steel bars 7, each second annular steel bar 6 passes through an operation hole 12 on a bearing wall 5, and each group of outer beams and inner beams are formed by coating the steel bars in the section, namely, the transverse steel bars 7 and the second annular steel bars 6 by ultra-high-performance concrete 16 and filling all operation holes 12 of the section, in which the second annular steel bars 6 are inserted.

The two ends of each group of outer cross beams 18 and inner cross beams 17, namely the outer cross beams 18 and the inner cross beams 17 in each group of cross beams, are connected with the top ends of each group of outer stand columns 3 and the top ends of the inner stand columns 4, namely the top ends of the outer stand columns 3 and the top ends of the inner stand columns 4 in each group of stand columns through nodes: the third annular steel bars 9 connected with the vertical steel bars 10 and penetrating through the respective operation holes 12 are connected with the transverse steel bars 7 of the outer cross beams 18 through the first L-shaped steel bars 11 and connected with the transverse steel bars 7 of the inner cross beams 17 through the second L-shaped steel bars 1, the two ends of each group of inner and outer cross beams and the top ends of each group of inner and outer stand columns are coated by ultra-high performance concrete 16 outside all steel bars and are filled with the operation holes 12 inserted into the third annular steel bars 9 to form connection nodes, and the steel bars in this section comprise the first annular steel bars 8, the second annular steel bars 6, the third annular steel bars 9, the vertical steel bars 10, the transverse steel bars 7, the L-shaped steel bars 11 and U-shaped steel bars 15.

The operating holes 12 are a plurality of operating holes 12 drilled on the bearing wall 5, and the diameter of the operating holes 12 is larger than that of the inserted reinforcing steel bars, and can be larger than one time or larger than two times, etc. The operation hole 12 is inserted into the annular reinforcing steel bar, and two free ends of the annular reinforcing steel bar are generally inserted into the operation hole, and the rest part of the annular reinforcing steel bar is also inserted into the operation hole 12, so that a gap between the annular reinforcing steel bar inserted into the operation hole 12 and the wall of the operation hole 12 is refilled. Of course, the loop bars refer to the first loop bar 8, the second loop bar 6, and the third loop bar 9.

The inner and outer beams of the plurality of groups of X-direction from left to right as in FIG. 1 and the inner and outer beams of the plurality of groups of Y-direction from top to bottom as in FIG. 1 are connected with each other to form a frame structure (only part of the outer beams can be seen in FIG. 1, and the inner beams can not be seen basically). The inner and outer beams are referred to herein as an inner beam 17 and an outer beam 18. The inner and outer columns here refer to one outer column 3 and one inner column 4, or one outer column 3 and two inner columns 4.

As shown in fig. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11.

The indoor construction auxiliary device of the reinforcing structure of the overground part of the multi-layer brick building according to any one of the technical schemes comprises U-shaped steel bars 15 at two ends, wherein the U-shaped steel bars 15 are respectively connected with a first annular steel bar 8 which is closely arranged below the joint of a third annular steel bar 9 and a second L-shaped steel bar 1, two free ends of each U-shaped steel bar 15 pass through two through holes on a vertical plate 36 of a steel bracket 20 with an L-shaped top, and two nuts 14 are respectively screwed on external threads 13 at two free ends of the U-shaped steel bar 15 so as to fix the steel bracket 20. Triangular reinforcing ribs 35 may be secured between the bottom plate of the L-shaped channel 19 of the steel corbel 20 and the risers 36 for added strength. The L-shaped templates 26 of the ultra-high performance concrete 16 poured with the inner cross beam 17 are detachably fixed in the L-shaped grooves 19 of the L-shaped steel corbels 20 at the two ends. The detachable fixing described here is understood to mean pressing by its own weight into the L-shaped groove 19 of the steel corbel 20, but it is of course also possible to fix temporarily by means of a plurality of screws. The indoor construction auxiliary device of the reinforcing structure of the overground part of the multi-layer brick building further comprises an indoor construction frame 24 with a ladder stand 22, a construction platform 25 and a plurality of rollers 23 for indoor construction.

The indoor construction auxiliary device for the reinforcing structure of the overground part of the multi-layer brick building according to any one of the above technical schemes of the utility model further comprises a detachable support rod 21 for supporting the middle of the length of the L-shaped template 26.

The top of the supporting rod 21 is an L-shaped block 30 for supporting the L-shaped template 26, a pair of ear plates 32 are fixed at the bottom of the L-shaped block 30, such as by welding, a pair of hinge holes 31 are formed in the ear plates 32, a hinge block 34 is fixed at the top of the supporting rod body 33, such as by welding, a hinge hole 31 is formed in the hinge block 34, and a hinge pin is inserted into the above three hinge holes 31 and is axially limited. The supporting rod body 33 is composed of three sections, a first threaded hole is formed in the bottom end of the upper section 29, a hexagonal column 28 with external threads is arranged in the middle section, a second thread is arranged in the top end of the lower section 27, the directions of the external threads at the two ends of the hexagonal column 28 are opposite, the directions of the first threaded hole and the internal threads of the second threaded hole are opposite, the external threads at the two ends of the hexagonal column 28 are screwed in the first threaded hole and the second thread, and the L-shaped template 26 is propped up by positive screwing or the L-shaped template is reversely screwed to be separated from the propping up.

The annular steel bars such as the first annular steel bar 8, the second annular steel bar 6 and the third annular steel bar 9 can be square steel bars. For the convenience of the operation of bar planting, the steel bar planting machine can be formed by bending a straight steel bar. The third loop bars 9 may also be referred to as node loop bars. The first annular steel bars 8 can be horizontally arranged and can be uniformly arranged at intervals up and down. The second annular steel bars 6 may be vertical and may be uniformly spaced along the length of the beam. The third annular steel bars 9 can be horizontally arranged and can be evenly arranged at the node at intervals up and down. It is not difficult to understand: the third loop bars 9 are much denser than the first loop bars 8 and the third loop bars 9 are much denser than the second loop bars 6. The reinforcing bars are connected or fixed with each other, such as between the annular reinforcing bars and the vertical reinforcing bars 10 and the transverse reinforcing bars 7, between the L-shaped reinforcing bars and the annular reinforcing bars and the transverse reinforcing bars 7, between the U-shaped reinforcing bars 15 and the annular reinforcing bars, and the like, and can be fixed by binding or spot welding.

The above-noted components or structures or numbers are not shown in the figures. The drawings are schematic only, and the text descriptions will be followed if the drawings do not coincide with the text descriptions or if the drawings do not coincide with each other.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, and various modifications and variations of the present utility model will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (5)

1. The reinforcing structure comprises a plurality of groups of outer columns and inner columns which are used for reinforcing the bearing wall of the multi-layer building, wherein each group of outer columns and inner columns comprises a plurality of vertical steel bars and a plurality of first annular steel bars connected with the plurality of vertical steel bars, each first annular steel bar penetrates through an operation hole in the bearing wall, and each group of inner columns and outer columns is formed by coating ultra-high performance concrete outside the steel bars and filling all operation holes inserted with the first annular steel bars; the method is characterized in that:

the system comprises a plurality of groups of outer beams and inner beams, wherein the outer beams and the inner beams are used for reinforcing a floor and clinging to the bottom surface of the floor, each group of outer beams and each group of inner beams comprise a plurality of transverse steel bars and a plurality of second annular steel bars connected with the plurality of transverse steel bars, each second annular steel bar penetrates through an operation hole on a bearing wall, and each group of inner beams and each group of outer beams are formed by coating the steel bars with ultra-high performance concrete and filling all operation holes inserted with the second annular steel bars;

the two ends of each group of outer cross beams and inner cross beams are connected with the top ends of each group of outer stand columns and the top ends of the inner stand columns through nodes: the plurality of third annular steel bars connected with the plurality of vertical steel bars and penetrating through the respective operation holes are connected with the plurality of transverse steel bars of the outer cross beam through the plurality of first L-shaped steel bars and connected with the plurality of transverse steel bars of the inner cross beam through the plurality of second L-shaped steel bars, and the two ends of each group of inner and outer cross beams and the top ends of each group of inner and outer stand columns are coated outside the steel bars through ultra-high performance concrete and are filled with all operation holes inserted with the third annular steel bars to form a connection node.

2. The reinforcing structure for the aerial parts of a multi-layered brick building according to claim 1, wherein: the inner and outer cross beams in the X direction and the inner and outer cross beams in the Y direction are connected with the inner and outer stand columns in the Y direction to form a frame structure.

3. An indoor construction assisting apparatus for a reinforcing structure of an overground part of a multi-layered brick building according to claim 1 or claim 2, characterized in that: the steel bracket comprises U-shaped steel bars at two ends, wherein the U-shaped steel bars are respectively connected with a first annular steel bar below the joint of a third annular steel bar and a second L-shaped steel bar, two free ends of each U-shaped steel bar penetrate through two through holes on a steel bracket vertical plate with an L-shaped top, and two nuts are respectively screwed on external threads at two free ends of the U-shaped steel bar to fix the steel bracket; the L-shaped template for pouring the ultra-high performance concrete of the inner cross beam is detachably fixed in the L-shaped grooves of the L-shaped steel corbels at the two ends; the indoor construction frame with the crawling ladder, the construction platform and the plurality of rollers for indoor construction is further included.

4. An indoor construction auxiliary device for reinforcing structures of overground parts of multi-layered brick-laid buildings according to claim 3, characterized in that: the detachable support rod is used for supporting the middle of the length of the L-shaped template.

5. The indoor construction auxiliary device for reinforcing structures of overground parts of multi-layered brick-laid buildings according to claim 4, characterized in that: the top of the supporting rod is an L-shaped block for supporting the L-shaped template, a pair of ear plates are fixed at the bottom of the L-shaped block, a pair of hinge holes are formed in the ear plates, a hinge block is fixed at the top of the supporting rod body, a hinge hole is formed in the hinge block, and a hinge pin is inserted into the three hinge holes and is axially limited; the bracing piece body comprises three sections, and there is first screw hole the bottom of upper segment, and the middle section is the hexagon post that both ends are external screw thread, and there is the second screw thread on the top of hypomere, and the opposite direction of the external screw thread at hexagon post both ends, the opposite direction of the internal screw thread of first screw hole and second screw hole, the external screw thread at hexagon post both ends is closed in first screw hole and second screw thread soon, and the positive rotation is in order to prop the L font template or be contrary to rotate in order to break away from the top to prop.