CN210104972U - Arch foot node - Google Patents
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- CN210104972U CN210104972U CN201920559188.1U CN201920559188U CN210104972U CN 210104972 U CN210104972 U CN 210104972U CN 201920559188 U CN201920559188 U CN 201920559188U CN 210104972 U CN210104972 U CN 210104972U
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Abstract
The utility model provides an arch springing node, it includes: a concrete column; the concrete columns are connected with two concrete beams which are arranged at intervals, one end of each concrete beam is stressed by tension, the other end of each concrete beam is stressed by pressure, and the stress directions of the two concrete beams are the same; the two embedded section steels are respectively embedded and arranged on two opposite sides in the concrete column, and the top end parts of the embedded section steels are flush with the top end of the concrete column; and the connecting line direction of the two embedded section steels is vertical to the arrangement direction of the concrete beam. So set up, pre-buried shaped steel and concrete column combined work have resisted the horizontal force that the concrete beam received, and the concrete beam can form effectual restraint to the concrete column simultaneously. The utility model provides an arch springing node is with less cross-section, solves current large-span arch structure arch springing department and need set up the problem of huge basis.
Description
Technical Field
The utility model relates to a building structure technical field, in particular to hunch foot node.
Background
In the existing large-span arch structure, there are generally the following structural forms:
1. single arch + buried prestressed pull rod + pile foundation: common prestressed pull rods in the foundation form comprise prestressed concrete pull beams, prestressed steel pull cables and the like. The prestressed straining beam or the inhaul cable is mainly used for balancing horizontal outward thrust generated by the arch springing under the working conditions of constant load, roof live load, temperature rise and the like. As shown in fig. 1, it is a schematic structural diagram of a national stadium in costa rica, and includes two long-span single-arch structures, two arch legs of each single-arch structure are connected with a large foundation, and a prestressed cable is connected between the two arch legs of each single-arch structure, and the foundation body is mainly formed by a plurality of long and short piles. The prestress balance part thrust of the prestress inhaul cable is utilized, and the bearing capacity requirement of the structure is met through fewer piles.
2. Single arch + pile group foundation: generally, the horizontal bearing capacity of a common single vertical cast-in-place pile is small, and the requirements of bearing capacity and deformation control cannot be met, so that in engineering design, the bearing capacity and the deformation requirements of an arch springing are often met by arranging a plurality of vertical piles or inclined piles below a bearing platform. For example, the comprehensive sports center of the Qinghua university and the Hangzhou large theatre and the like adopt a pile group foundation as the foundation of an arch structure. As shown in fig. 2(a) and 2(b), fig. 2(a) is a plan view of a column foot foundation of a hangzhou theater, and fig. 2(b) is a cross-sectional view of the column foot foundation shown in fig. 2(a), which mainly uses cement mixing piles and precast piles to form the pile group foundation 14. The single arch span of the Hangzhou large theatre reaches 172m, the range of pile group foundation is larger, the size of about 12m multiplied by 8m is achieved on the plane, and the height of 5.4m (the depth without precast pile) is achieved in the longitudinal direction.
3. Multi-arch, ring beam and prestressed pipe pile cap foundation: the ring beam foundation is a relatively novel foundation form in a large-span arch structure. The annular beam bears the horizontal load transmitted by the arch springing of the multi-channel arch, and is integrally pulled in the plane of the annular beam to form a self-balancing system, so that the huge horizontal load resistance of the foundation can be effectively exerted, and the deformation of the upper structure is coordinated. As shown in fig. 3, it is a schematic structural diagram of a sports convention and exhibition center in southeast city, and its roof includes six main arches in east-west direction, five auxiliary arches and two oblique arches in north-south direction, the main arch is continuous in full span, and the auxiliary arch is disconnected at the oblique arch. The maximum span of the main arch is 278m, the maximum rise is 55m, and the span of the oblique arch is 280 m. Each arch adopts a triangular circular steel tube space truss, three arch chords are hinged with a reinforced concrete foundation, and the scheme of the foundation under the arch adopts an integral ring beam foundation and a multi-pile bearing platform and a prestressed pull rod. The vertical counter-force and bending moment of the arch are borne by the pile, and the horizontal thrust is borne by the ring beam, the lateral resistance of the soil and the pull rod together.
4. Other forms: as shown in figure 4, the structure of the gymnasium of the Nanjing Olympic center is schematically shown, the roof structure of the Nanjing Olympic center gymnasium mainly comprises two variable-section triangular truss arches with the span of 376m and the inclination of 45 degrees, the horizontal thrust at the support of the variable-section triangular truss arch reaches 13000kN, and in order to meet the requirements of the horizontal thrust and the horizontal displacement at the arch support, according to the principle of 'bow', the underground crossing the stadium between the two arch foot bases is connected by unbonded prestressed tendons to be used as the 'string' of a large oblique arch, so that the large oblique arch and the arch form a 'bow' structure.
In summary, the large-span arch structure is widely applied to large-span structures and space structures such as gymnasiums and exhibition centers as a reasonable and effective structural system. From the mechanical point of view, the arch structure converts the bending moment generated by external load into the axial tension and compression force of the component, and can effectively utilize the characteristics of structural materials, thereby continuously improving the efficiency of the structure. However, the arch structure system is established on the premise that the support at the arch foot is required to provide a large horizontal thrust force for maintaining the structure in balance, so that the arch structures generally seen have a huge foundation for resisting the horizontal thrust force. This limits the application of the large-span arch structure in some buildings, for example, when the first floor of the building needs to be erected, the huge foundation at the arch foot will destroy the form and function of the building.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an arch springing node to solve current large-span arch structure arch springing department and need set up the problem of huge basis.
In order to solve the technical problem, the utility model provides an arch springing node, it includes:
a concrete column;
the concrete columns are connected with two concrete beams which are arranged at intervals, one end of each concrete beam is stressed by tension, the other end of each concrete beam is stressed by pressure, and the stress directions of the two concrete beams are the same; and
the two embedded section steels are arranged along the axial direction of the concrete column, the two embedded section steels are respectively embedded and arranged on two opposite sides in the concrete column, and the top end parts of the embedded section steels are flush with the top end of the concrete column; and the connecting line direction of the two embedded section steels is vertical to the arrangement direction of the concrete beam.
Optionally, the embedded steel comprises a cross-shaped web plate arranged along the axial direction of the concrete column.
Optionally, the embedded section steel further comprises four wing plates, and the four wing plates are respectively connected with different end portions of the web plate.
Optionally, the side of the wing plate away from the web is provided with a plurality of pegs.
Optionally, the embedded profile steel further includes a plurality of stiffening plates transversely disposed along the concrete column, the plurality of stiffening plates are disposed at intervals along an axial direction of the concrete column, and all the stiffening plates are disposed inside an area enclosed by the four wing plates and connected to the web and the wing plates.
Optionally, each stiffening plate is divided into four sub stiffening plates by the web plate, and through holes are formed in the four sub stiffening plates.
Optionally, a plurality of horizontal stiffening ribs are arranged between the two pre-embedded section steels, and two ends of each horizontal stiffening rib are connected with the two pre-embedded section steels respectively.
Optionally, a plurality of horizontal stiffening ribs are provided with through holes.
Optionally, two be equipped with a plurality of vertical stiffening ribs between the pre-buried shaped steel, vertical stiffening rib with horizontal stiffening rib is mutually perpendicular, just vertical stiffening rib is with a plurality of horizontal stiffening rib all connects.
Optionally, the top of the concrete beam is flush with the top end of the concrete column.
To sum up, the utility model provides an among the hunch foot node, set up pre-buried shaped steel in concrete column, and the top portion of pre-buried shaped steel with the top portion looks parallel and level of concrete column, so set up, pre-buried shaped steel and concrete column combined work have resisted the horizontal force that the concrete beam received (the pulling force of one side and the pressure of opposite side promptly), and the concrete beam can form effectual restraint to concrete column simultaneously. In addition, the connecting direction of the two embedded section steels is perpendicular to the arrangement direction of the concrete beam, so that two supporting points for supporting the upper arch structure are formed, and the force of the upper arch structure can be uniformly transmitted to the outside. The utility model provides an arch springing node is with less cross-section, solves current large-span arch structure arch springing department and need set up the problem of huge basis.
Drawings
Those skilled in the art will appreciate that the drawings are provided for a better understanding of the invention and do not constitute any limitation on the scope of the invention. Wherein:
FIG. 1 is a schematic diagram of the structure of a Costa Ricken national stadium;
fig. 2(a) is a plan view of a pedestal base of a hangzhou theater;
FIG. 2(b) is a cross-sectional view of the column shoe foundation shown in FIG. 2 (a);
FIG. 3 is a schematic diagram of a structure of a sports convention center in southbound;
FIG. 4 is a schematic diagram of the structure of a Nanjing Olympic center gym;
fig. 5 is a schematic view of a combined arch structure according to an embodiment of the present invention;
fig. 6 is a schematic plan view of an arch springing node according to an embodiment of the present invention;
fig. 7 is a perspective view of an arch springing node according to an embodiment of the present invention, wherein the concrete portion is not shown;
fig. 8 is a front view of a model loading test according to an embodiment of the present invention;
FIG. 9 is a cross-sectional view taken along line 1-1 of FIG. 8;
FIG. 10 is a cross-sectional view taken along line 2-2 of FIG. 8;
fig. 11 is a graph of beam-end load-displacement hysteresis of a model loading test according to an embodiment of the present invention;
fig. 12 is a skeleton curve diagram of a test piece of a model loading test provided by an embodiment of the present invention.
In the drawings:
11-single arch structure; 12-a prestressed guy cable; 13-a base; 14-pile group foundation; 15-main arch; 16-secondary arch; 17-oblique arch; 18-ring beam foundation; 19-unbonded prestressed tendons;
100-a first arch; 200-a second arch; 210-a connecting segment; 220-a brace bar; 300-cross bracing; 400-horizontal linkage member; 510-a concrete column; 520-a concrete beam; 521-a first concrete beam; 522-a second concrete beam; 530-pre-buried section steel; 531-web; 532-wing plate; 533-stiffener; 534-a via; 540-studs; 550-horizontal stiffeners; 551-through hole; 560-vertical stiffeners; 571-an actuator; 572-Loading base.
Detailed Description
To make the objects, advantages and features of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be noted that the drawings are in simplified form and are not to scale, but rather are provided for the purpose of facilitating and distinctly claiming the embodiments of the present invention. Further, the structures illustrated in the drawings are often part of actual structures. In particular, the drawings may have different emphasis points and may sometimes be scaled differently.
As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise, and the term "upper" generally refers to a distance from the ground relative to the term "lower" unless the content clearly dictates otherwise.
The utility model discloses a core thought lies in providing an arch springing node, and it includes: the concrete column and the two spaced concrete beams are connected with the concrete column, one end of each concrete beam is stressed by tension, the other end of each concrete beam is stressed by pressure, and the stress directions of the two concrete beams are the same; the two embedded section steels are respectively embedded and arranged on two opposite sides in the concrete column, and the top end parts of the embedded section steels are flush with the top end part of the concrete column; and the connecting line direction of the two embedded section steels is vertical to the arrangement direction of the concrete beam. So set up, pre-buried shaped steel and concrete column combined work have resisted the horizontal force that the concrete beam received (be the pulling force of one side and the pressure of opposite side), and the concrete beam can form effectual restraint to the concrete column simultaneously. In addition, the connecting direction of the two embedded section steels is perpendicular to the arrangement direction of the concrete beam, so that two supporting points for supporting the upper arch structure are formed, and the force of the upper arch structure can be uniformly transmitted to the outside. The utility model provides an arch springing node is with less cross-section, solves current large-span arch structure arch springing department and need set up the problem of huge basis.
The following description refers to the accompanying drawings.
Referring to fig. 5, which is a schematic view of a combined arch structure according to an embodiment of the present invention, it should be understood that only the combined arch structure itself is illustrated, and other structural members, such as columns and beams, for providing supporting force to the combined arch structure are not illustrated.
As shown in fig. 5, the present invention provides a combined arch structure, which includes a first arch 100, a second arch 200, two cross braces 300 and a horizontal connection member 400, wherein the second arch 200 is stacked on the first arch 100 at intervals, and two arch feet (i.e. the bottoms of two ends of the arch) of the second arch 200 are connected with the two arch feet of the first arch 100; one end (upper end) of each of the two cross braces 300 is connected to two arch legs of the first arch body 100, and the other end (lower end) of each of the two cross braces 300 is used for connecting to the outside (such as a foundation) to transmit force outwards; both ends of the horizontal linking member 400 are respectively connected with the two arch feet of the first arch body 100.
In the combined arch structure, two arch bodies (namely the first arch body 100 and the second arch body 200) are combined for use, so that the arch span (the integral span of the combined arch, mainly the upper arch span of the two arch bodies, such as the second arch body 200 in the embodiment) can be effectively increased, the arch rise (also referred to as the integral arch rise) can be reduced, the whole combined arch structure is more gentle, and the combined arch structure is suitable for occasions where the arch bodies are expected to be gentler. However, if two arch bodies are arranged in the combined arch structure, that is, four arch feet are arranged, and if huge foundations are arranged on the arch bodies, the using function of the building is obviously influenced, and the appearance is also influenced. The inventor finds that in the arch structure system, the arch body can generate larger horizontal pushing force on the arch foot, and the arch body is generally balanced by a huge foundation and the like. If the horizontal thrust is balanced by means of a prestressed pull rod and the like, the arch springing is generally required to be directly connected with the soil body, and then the pull rod with a larger size is arranged, so that the pull rod also needs to be embedded in the foundation. In the combined arch structure provided by the embodiment, on one hand, the horizontal connection member 400 is used for bearing horizontal thrust at two ends of the first arch 100 and the second arch 200, and the two cross supports 300 are arranged for bearing horizontal thrust at two ends of the first arch 100 and the second arch 200, so that the horizontal connection member 400 and the cross supports 300 act together to be redundant to each other, thereby forming two safety lines, and even if one of the horizontal connection member 400 and the cross supports 300 is damaged under the action of earthquake force or other conditions, the whole structure can be ensured to be stable. On the other hand, mainly adopt twice cross support 300 to pass power outward, cancelled the huge basis that current large-span arch structure arch springing department set up, enlarged the utility model provides a combined arch structure's range of application. For example, the combined arch structure provided by the embodiment can be applied to an overhead building, that is, the lower part supports the combined arch structure through a plurality of columns and beams, so that the combined arch structure is in a suspension shape, and the combined arch structure does not adversely affect the spatial form and functional combination of the lower part.
Preferably, the first arch body 100 and the second arch body 200 are both steel trusses; the two arch feet of the second arch body 200 are connected with the two arch feet of the first arch body 100 through a connecting section 210; the span of the second arch 200 is greater than the span of the first arch 100. More preferably, the second arch 200 and the first arch 100 are further connected by a plurality of struts 220. The arch body adopts the structural style of steel truss, can realize that overall structure is lighter, realizes the effect that the span is bigger. The second arch body 200 is connected with the first arch body 100 through a plurality of support rods 220, so that the whole combined arch structure is more stable, and a combined stress system is formed. In the whole combined arch structure, the first arch body 100 and the second arch body 200 are connected through the support rods to form the combined arch structure, under the action of vertical load, all the rods (especially midspans) of the second arch body 200 are in a compressed state, and the rods in the midspans of the first arch body 100 are in a tension state.
Preferably, the horizontal linkage member 400 includes a prestressed cable, and further includes a floor and/or a beam parallel to the prestressed cable. The prestressed cables are mainly used for being pulled to balance the horizontal pushing force at the two arch feet of the first arch 100 and the second arch 200, but in practice, the floor and the beam perpendicular to the arching direction (i.e. parallel to the prestressed cables) can also transmit the horizontal force, and can effectively share the pulling force received by the horizontal linking member 400. Thus, the floor and/or the beam parallel to the prestressed guy can also be considered as part of the horizontal linkage member 400.
Further, the cross braces 300 are arranged in a V shape, and the open ends of the cross braces 300 are connected with the arch feet of the first arch body 100. Generally, the cross brace 300 may be in several forms, such as an X-shaped arrangement or a V-shaped arrangement, and if the X-shaped arrangement is adopted, a large number of welding seams are required to be constructed on site at the cross position, which requires high conditions for the site construction. The present embodiment preferably employs cross supports 300 in a V-shaped arrangement. However, when the cross brace 300 adopts the V-shaped arrangement, the slenderness ratio of its members is relatively large (about twice as large as that of the X-shaped arrangement). To solve the problem of a large aspect ratio, simply enlarging the cross section of the member easily causes the rigidity of the cross brace to be sharply increased, thereby greatly reducing the installation effect of the horizontal linking member 400, and on the other hand, enlarging the cross section of the member affects the building space under the combined arch structure.
Therefore, the inventors have studied to find that the problem of the V-shaped arrangement in which the cross-brace slenderness ratio is large can be solved by using the buckling-restrained brace member. Buckling Restrained Braces (BRB) are also called anti-buckling Braces and are ideal shock-absorbing brace systems. The buckling restrained brace comprises a steel bracing inner core, an outer wrapping restraining member (such as a steel pipe, reinforced concrete or steel pipe concrete) and a gap layer, wherein the gap layer is arranged between the steel bracing inner core and the outer wrapping restraining member. The gap layer can be, for example, a non-adhesive layer or a gap. The outer wrapping restraining component of the buckling restrained brace can restrain the transverse deformation of the brace and ensure that the pressure and the tensile force are only born by the inner core of the steel brace. The gap layer allows relative sliding between the steel support inner core and the outer wrapping constraint member while constraining lateral deformation of the steel support inner core. The external constraint component can not change the allowable tensile rigidity of the support, but can prevent the steel support inner core from buckling under the action of pressure, and can greatly improve the compressive rigidity and the bearing capacity of the support, so that the buckling constraint support has good hysteretic energy dissipation performance when resisting repeated loads of an earthquake. Generally, the buckling restrained brace component is mainly applied to anti-seismic design, under the action of rare earthquakes, the buckling restrained brace can be quickly buckled under the conditions of tension and compression, the structural damping is improved, the transmitted seismic energy is effectively consumed, the main structure is prevented from being seriously damaged, the yielding bearing capacity of the common brace is far smaller than the yielding bearing capacity of the tension due to compression and becomes larger along with the increase of the length of the brace, and the anti-seismic capacity of the structure is sharply reduced due to the instability of the compression under the action of rare earthquakes, so that the main structure is easy to damage.
In the present embodiment, the inventors found that when the buckling restrained brace member generally used for the anti-seismic design is innovatively applied to the cross brace, the problem of the V-shaped arrangement that the cross brace has a large slenderness ratio can be solved by utilizing the characteristic that the buckling restrained brace member is not subjected to buckling. Furthermore, as the buckling restrained brace members have no instability problem when being pressed, the cross section is smaller and the overall rigidity of the building is smaller under the same bearing capacity condition as that of the common brace, and the arrangement function of the horizontal connection member 400 cannot be influenced. It has been calculated that with a V-shaped arrangement of cross braces (which include buckling restrained brace members), the majority of the horizontal thrust at the arch springing of the composite arch structure is taken up by the horizontal linkage members 400.
In some embodiments, the horizontal connecting member 400 is formed by floor slab, prestressed cables, and beams, and the force transmission mechanism is complicated, so that it is necessary to add a safety line. By improving the ultimate bearing capacity of the buckling restrained brace, the buckling restrained brace can play a role of two defense lines, namely when the horizontal connection component 400 is damaged by an accident (such as earthquake force), the cross braces arranged in the V shape can transmit the horizontal thrust at the arch springing of the combined arch structure to the outside (such as a foundation), so that the serious damage is avoided.
In an exemplary embodiment, the inventors have calculated that more than about 80% of the horizontal forces generated by the arches (including first arch 100 and second arch 200) are balanced by horizontal linking members 400, and less than 20% are borne by cross-braces 300. Even if the horizontal linking member 400 is broken in some special cases, the cross brace 300 can bear all the horizontal force generated by the arch without being broken.
Under the action of earthquake force, the load condition of the combined arch structure is complex in practice, and as the arch springing node (as shown in a point A in figure 5) of the combined arch structure is not only a support of the combined arch structure, but also a connecting node for transmitting the horizontal force of the arch springing to an external concrete structure and a cross support, the arch springing node is a key part of the whole combined arch structure, and the stress performance of the arch springing node directly influences the safety of the combined arch structure. Therefore, the inventor also verifies and calculates the arch springing node of the combined arch structure provided by the embodiment, so as to ensure that the arch springing node can keep certain stability under the action of earthquake force without sudden damage and the like.
The following describes the arch springing node of the combined arch structure provided by the present embodiment with reference to fig. 6 and 7: as shown in fig. 6 and 7, the arch springing node includes: the concrete column comprises a concrete column 510, two spaced concrete beams 520 and two embedded section steels 530 arranged along the axial direction of the concrete column 510, wherein the two concrete beams 520 are both connected with the concrete column 510, one end of each concrete beam 520 is under tension, the other end of each concrete beam 520 is under pressure, and the two concrete beams 520 are in the same stress direction; the two pre-buried section steels 530 are pre-buried in two opposite sides of the concrete column 510 respectively, and the top ends of the pre-buried section steels 530 are flush with the top end of the concrete column 510; the connecting direction of the two embedded section steels 530 is perpendicular to the arrangement direction of the concrete beam 520. The two concrete beams 520 include a first concrete beam 521 and a second concrete beam 522 which correspond to the arrangement positions of the two embedded section steels 530, respectively.
Due to the fact that the embedded profile steel 530 is arranged in the concrete column 510, and the top end portion of the embedded profile steel 530 is flush with the top end portion of the concrete column 510, the embedded profile steel 530 and the concrete column 510 work together to resist horizontal force (namely pulling force on one side and pressure on the other side) borne by the concrete beam 520, and meanwhile the concrete beam 520 can effectively restrain the concrete column 510. In addition, the connecting direction of the two embedded steel bars 530 is perpendicular to the arrangement direction of the concrete beam 520, and two supporting points for supporting the upper arch structure (e.g., the combined arch structure) are formed, so that the force of the upper arch structure can be uniformly transmitted to the outside. The arch springing node uses a smaller section to replace the existing arch springing of the large-span arch structure and needs to be provided with a huge foundation.
Preferably, pre-buried shaped steel 530 includes along criss-cross web 531 that the axial of concrete column 510 set up, pre-buried shaped steel 530 still includes four pterygoid lamina 532, and four pterygoid lamina 532 are followed the circumference of web 531 distributes, respectively with the end connection of the difference of web 531. As shown in fig. 6, the web 531 of the embedded steel 530 is preferably composed of four steel plates perpendicular to each other, such as by welding, or integrally formed by a factory. At the ends of the four steel plates, a wing 532 is disposed, for example, by welding, so as to form a crisscross structure. More preferably, the side of the wing 532 remote from the web 531 (i.e., the side of the outer surface) is provided with a plurality of pegs 540, such as by welding, to fixedly attach the pegs 540 to the wing 532. The setting of the pegs 540 effectively ensures the adhesive property between the embedded profile steel 530 and the concrete, and enables the embedded profile steel 530 and the concrete to work together.
Further, the embedded steel 530 further includes a plurality of stiffening plates 533 disposed along the transverse direction of the concrete column 510, the plurality of stiffening plates 533 are disposed at intervals along the axial direction of the concrete column 510, and all the stiffening plates 533 are disposed inside an area enclosed by four wing plates 532, and are connected (e.g., welded) with the web 531 and the wing plates 532. The stiffening plates 533 are transversely arranged, that is, arranged perpendicular to the axial direction of the embedded steel 530, that is, the stiffening plates 533 are perpendicular to the web 531 and the wing plates 532. By arranging the plurality of stiffening plates 533, the lateral force resistance of the embedded profile steel 530 can be improved, so that the horizontal force transmitted by the combined arch structure can be better resisted. Alternatively, the number of the stiffening plates 533 may be 7, which are parallel to each other and are uniformly spaced apart. Furthermore, each stiffening plate 533 is divided into four sub stiffening plates by the web 531, and the four sub stiffening plates are all provided with through holes 534. Due to the existence of the web 531, on the cross section of the embedded steel 530, the stiffening plate 533 is divided into four sub stiffening plates by the web 531, wherein each sub stiffening plate is connected with the web 531 and the wing plate 532. The through hole 534 is mainly used for ventilation when concrete is poured so as to ensure that the pouring is compact.
Preferably, a plurality of horizontal stiffening ribs 550 are arranged between the two pre-embedded profile steels 530, and two ends of each horizontal stiffening rib 550 are respectively connected with the two pre-embedded profile steels 530. The horizontal stiffeners 550 are also arranged in the horizontal direction, i.e. perpendicular to the axial direction of the embedded steel 530. Specifically, the axial direction of the pre-embedded steel sections 530 is vertical, and the horizontal stiffeners 550 are horizontal. Through the setting of horizontal stiffening rib 550, connect two pre-buried shaped steel 530, can make two pre-buried shaped steel 530 keep the joint work. Preferably, the arrangement pitch and the number of stiffening plates 550 are the same as those of stiffening plates 533. More preferably, a plurality of horizontal stiffening ribs 550 are all provided with a through hole 551, and the through holes 551 are used for concrete injection and can also be used for ventilation during concrete pouring, and the vibrating device can enter the inside of the embedded profile steel 530 conveniently to ensure compact pouring.
Preferably, a plurality of vertical stiffening ribs 560 are further disposed between two of the pre-embedded profile steels 530, the vertical stiffening ribs 560 are perpendicular to the horizontal stiffening ribs 550, and the vertical stiffening ribs 560 are connected to a plurality of the horizontal stiffening ribs 550. The vertical stiffening ribs 560 are arranged, so that the connection strength and reliability between the two embedded section steels 530 are further enhanced. Preferably, two vertical stiffeners 560 are respectively disposed on two sides of the horizontal stiffener 550, and the two vertical stiffeners 560 can be flush with the wing plates 532 of the two embedded sections 530. Preferably, a third vertical stiffening rib 560 is further disposed at the middle point of the connecting line of the two pre-buried section steels 530. The third vertical stiffener 560 is perpendicular to the connection line of the two pre-embedded profile steels 530, that is, the third vertical stiffener 560 is disposed on the symmetry plane of the two pre-embedded profile steels 530.
Preferably, the top of the concrete beam 520 is flush with the top end of the concrete column 510 so as to form a bearing plane for erecting the composite arch structure. Optionally, a top plate, such as a steel plate, may be further disposed at the top end of the concrete column 510, so as to seal the embedded steel 530, and facilitate connection of the members of the combined arch structure.
In an exemplary embodiment, the span (L1 in fig. 5) of the first arch 100 is 120m, the rise is 17m, and the finite element software ABAQUS is used to model the arch node by non-linear finite element analysis, so as to simulate the design load applied to the arch node by the composite arch structure under a seismic force, such as the vertical load applied to the arch node is about 3860kN, and the horizontal load is about 15000 kN. Under the action of design loads (including vertical loads and horizontal loads), one side of the joint of the concrete beam 520 of the arch springing node and the concrete column 510 is under tension, and the other side is under pressure. The calculation result shows that the tensile force of the concrete beam on the tension side is large, the concrete is cracked, the longitudinal steel bar is yielded, the overall pressure level of the concrete beam on the compression side is low, and the maximum compression stress value is far smaller than the designed compression strength value; the overall stress level of the embedded section steel is not high, but a local stress concentration phenomenon exists, and the maximum stress at the stress concentration position reaches about 300 MPa; the maximum stress of longitudinal bars and stirrups (the longitudinal bars and the stirrups are conventionally configured according to specifications) in the concrete column is 65MPa and is far smaller than the designed strength value; concrete beams on two sides of the arch springing node form effective restraint on the concrete columns. Thus, the lateral deformation of the arch foot node under design load is less.
Further, the inventor conducted 1/5 scale model loading tests on the arch springing node, as shown in fig. 8 to 10, wherein fig. 8 is a front view of the model loading tests, fig. 9 is a sectional view of fig. 8 taken along the line 1-1, and fig. 10 is a sectional view of fig. 8 taken along the line 2-2. The 10000kN large-scale multifunctional structural testing machine system is used for loading, the testing machine system comprises an actuator 571 and a loading base 572, and a test piece is arranged on the loading base 572 and loaded by the actuator 571. Under vertical loading or horizontal loading, the actuator 571 can follow the test piece, and the follow-up displacement can be determined according to the loading strokes of the vertical actuator and the horizontal actuator. The test piece is manufactured according to the 1/5 reduced scale model of the arch springing node, wherein the configuration of longitudinal steel bars and stirrups in the concrete beam and the concrete column are reasonably arranged according to the specification, and the result of the model loading test is as follows:
firstly, the final failure form characteristics of the test piece (namely) of the model loading test are as follows:
1. the initial crack position of the test piece appears at the side beam end of the column, and when the horizontal load is large, a horizontal crack appears on the column;
2. the final damage of the test piece occurs at the interface of the beam and the column, which is specifically shown in the way that a wider crack occurs at the interface of the beam and the column, and the concrete at the beam end is crushed and peeled off;
3. under the action of horizontal load of the top of the column, a bending crack appears at the beam end, the width of the crack is gradually increased along with the increase of the horizontal load of the top of the column, and the distribution range of the crack is gradually expanded from the junction of the beam and the column to the direction of the beam support; the node core area only has a few oblique cracks when the whole test piece is about to be damaged. The forward cracks and the reverse cracks on the test piece beam are basically symmetrically distributed on one side beam. The forward cracks and the reverse cracks on the test piece column are basically distributed symmetrically.
Secondly, the beam end longitudinal steel bar strain conditions of the model loading test are as follows:
1. under repeated load, the strain of the longitudinal steel bar at the beam end of the test piece is positive and negative alternately, and the test piece shows corresponding hysteresis characteristics;
2. under repeated load, the strain distribution of the longitudinal steel bar at the beam end of the test piece is asymmetric, and the positive value strain (namely tensile strain) is obviously larger than the negative value strain (namely compressive strain);
3. when the test piece cracks in the positive direction, the maximum tensile strain of the longitudinal steel bar is 665 mu epsilon; the maximum tensile strain of the longitudinal steel bar when the test piece is reversely cracked is 481 mu epsilon;
4. when the test piece reaches the positive peak load, the longitudinal steel bar is already yielding, and the maximum strain value reaches 3176 mu epsilon.
Thirdly, strain conditions of the column end longitudinal steel bars in the model loading test are as follows:
1. under repeated load, the strain value of the longitudinal steel bar at the column end of the test piece is alternated between positive and negative, corresponding hysteresis characteristics are shown, and the strain change rule is obvious;
2. under repeated load, the strain distribution of the longitudinal steel bar at the column end of the test piece is basically symmetrical, but the positive value strain (namely tensile strain) is still larger than the negative value strain (namely compressive strain);
3. the maximum value of the compressive strain of the longitudinal steel bar is-300 mu epsilon when the test piece cracks in the positive direction; when the test piece is reversely cracked, the maximum value of the compressive strain of the longitudinal steel bar is-280 mu epsilon; the longitudinal steel bar tensile strain of the concrete column is still very small at this moment;
4. when the test piece reaches the positive peak load, the maximum strain values of the longitudinal steel bar of the column under tension and compression are 1550 mu epsilon and-850 mu epsilon respectively; when the test piece reaches the reverse peak load, the maximum strain values of the longitudinal steel bar of the column in the pulling and pressing directions are 2742 mu epsilon and-700 mu epsilon respectively.
Fourthly, the strain condition of the stirrup in the model loading test is as follows:
1. under repeated load, the strain value of the stirrup of the test piece is alternated between positive and negative, and the corresponding hysteresis characteristic is shown;
2. in the whole test process, only a small amount of shear cracks appear on the test piece, and the test piece is still kept intact in the later stage of the test, which shows that the shear resistance of the arch springing node can meet the design requirements of a strong node and a weak member;
3. in the test process, the maximum strain value of the stirrup of the test piece is about 200 mu epsilon and is far smaller than the actually measured yield strain, which indicates that the stirrup is in an elastic state in the test process.
Fifthly, the strain condition of the embedded section steel in the model loading test is as follows:
1. in the test process, the main strain of the test piece embedded section steel changes along with the change of the load, and a certain hysteresis characteristic is presented;
2. in the whole test process, the maximum main tensile strain value on the pre-buried section steel is 600 mu epsilon; the maximum strain value of the main pressure is-1170 mu epsilon. It is shown that all parts of the embedded section steel are not subjected to yielding and still in an elastic state in the whole test process.
Sixthly, the load-deformation relation of the model loading test is as follows:
the hysteresis curve is a relation change curve between the load acting on the structure or the member and the corresponding displacement under the action of the reciprocating load, reflects the deformation characteristics, the energy dissipation and other characteristics of the structure or the member in the repeated stress process, is the comprehensive embodiment of the anti-seismic performance of the structure, and is also the basis for determining a restoring force model and carrying out nonlinear seismic response analysis. In the test, the average value of the horizontal displacement of the top of the concrete beam is used as a displacement item of a load-displacement curve, and the force value of a horizontal actuator (namely the force acting on the loading end of a test piece) is used as a load item of the load-displacement curve. The beam end load-displacement hysteresis curve of the test piece is shown in fig. 11. As can be seen from the figure:
1. the hysteresis curve of the test piece has 4 characteristic points which are respectively a cracking point, a yield point, a peak point and a limit point;
2. the hysteresis curve of the test piece is in a fusiform shape in the early stage, and the hysteresis ring is full; after the 2 delta is finished and the 3 delta is finished, the bearing capacity of the test piece is reduced obviously because the concrete beam is seriously damaged near the end part of the column;
3. the positive and negative curves of the hysteresis curve of the test piece are in antisymmetric distribution.
Seventhly, framework curve of model loading test:
the skeleton curve is an outer envelope of a hysteretic curve of the structure or the component, is a track of a maximum peak value of a horizontal force reached by each cyclic loading, and reflects different stages and characteristics (strength, rigidity, ductility, energy consumption and the like) of stress and deformation of the structure or the component. Fig. 12 is a skeleton graph of the test piece. As can be seen from the figure:
1. the test piece undergoes three stages of cracking, yielding and failure under the action of repeated loads. Before cracking, the load and displacement basically increase linearly, and the whole structure is in an elastic state at the stage; after cracking, the rigidity of the test piece is obviously reduced; after yielding, the rigidity of the test piece is continuously reduced along with the continuous increase of the displacement until the test piece is damaged;
2. the strength and rigidity of the test piece are obviously degraded after the bearing capacity reaches the peak value.
Eighthly, displacement ductility and deformability:
displacement ductility is a measure of the ability of a structure or component to deform. The ductility coefficient is usually used to indicate the ductility of the structural member or structure. Ductility factor is ultimate deformation Δu(i.e. ultimate displacement) and yield deformation deltay(i.e., yield displacement), i.e., μ ═ Δu/Δy. The yield of the test piece is generally marked by the yield of the component, and the corresponding load and displacement are called yield load PYAnd yield displacement Δy. It is difficult to determine the yield point of the test piece if there is no significant inflection point on the load-displacement curve of the test piece, in which case the yield point is usually determined by an equal energy method. The ductility coefficient of node displacement obtained by the energy method is shown in table 1. Ultimate displacement Δ of test pieceuThe displacement value of the beam end corresponding to the load capacity reduced to 85% of the peak load.
TABLE 1
From table 1 it can be derived:
1. the forward and reverse displacement ductility coefficients of the test piece are 1.59 and 1.71 respectively;
2.Δ of specimen in forward and reverse directionsy/ΔcrThe ratios are 3.11 and 3.06 respectively, which shows that the test piece has more abundant safety margin after cracking.
In conclusion, the initial crack position of the test piece appears at the column side beam end, and when the load level is large, the horizontal load appears on the column. The final damage of the test piece occurs at the interface of the beam and the column in the core area of the node, which is specifically shown in the way that a wider crack occurs at the interface of the beam and the column and the concrete at the beam end is crushed and peeled off; in the whole test process, the pre-embedded section steel of the test piece is not subjected to yielding, the stirrups are not subjected to yielding, large cracks and crushing phenomena are not generated in concrete, the arch springing node is basically in an elastic stress state, and the arch springing node is safe and reliable as a whole; the hysteresis curve of the test piece is full, which shows that the test piece has better energy consumption capability; the forward and reverse displacement ductility coefficients of the test piece are 1.59 and 1.71 respectively, and the design requirements are met. The low-solid repeated load test of the arch springing node model shows that the arch springing node can not generate plastic deformation and damage under the design load and is in an elastic stress state, the structure of the arch springing node has good bearing capacity and energy consumption capacity, the whole arch springing node is safe and reliable, and the whole stress safety of a combined arch structure and an external concrete structure can be ensured.
In addition, in general, in the structural design, all assumptions are the final finished state of the structure, but in the construction process, the internal stress state and the load of the whole structure are different from the normal use load, so that it is necessary to perform simulation analysis on the construction process. Through the analysis of the test, even if the combined arch structure is installed in a subsection step-by-step mode, under the condition that the horizontal connection component is not formed and bearing capacity cannot be formed, the stress and deformation of the arch foot node are in a controllable range, and the structural safety of the combined arch structure in the installation and construction process can be ensured. In addition, even under the action of earthquake force, the arch springing node is subjected to 1.4-1.6 times of design horizontal load, the safety can be ensured, namely the arch springing node meets the requirements and can replace the existing huge foundation.
In summary, in the combined arch structure provided by the present invention, on one hand, the horizontal connection member is used to bear the horizontal thrust at the two ends of the first arch and the second arch, and the two cross braces are arranged to also bear the horizontal thrust at the two ends of the first arch and the second arch, the horizontal connection member and the cross braces act together and are redundant to each other, so as to form two safety lines, even if one of the horizontal connection member and the cross braces is damaged under the action of earthquake force, the overall structure is also guaranteed to be stable; on the other hand, mainly adopt twice cross support to pass power outward, cancelled the huge basis that current large-span arch structure hunch foot department set up, enlarged the utility model provides a combined arch structure's range of application. In addition, the arch springing node of the combined arch structure has certain safety margin, and even under the action of earthquake force, the safety can be ensured.
The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and any modification and modification made by those skilled in the art according to the above disclosure are all within the scope of the claims.
Claims (10)
1. A soffit node, comprising:
a concrete column;
the concrete columns are connected with two concrete beams which are arranged at intervals, one end of each concrete beam is stressed by tension, the other end of each concrete beam is stressed by pressure, and the stress directions of the two concrete beams are the same; and
the two embedded section steels are arranged along the axial direction of the concrete column, the two embedded section steels are respectively embedded and arranged on two opposite sides in the concrete column, and the top end parts of the embedded section steels are flush with the top end of the concrete column; and the connecting line direction of the two embedded section steels is vertical to the arrangement direction of the concrete beam.
2. The arch springing node of claim 1, wherein the pre-embedded steel comprises a cross-shaped web disposed along an axial direction of the concrete column.
3. The arch springing node of claim 2, wherein the pre-embedded steel further comprises four wing plates, the four wing plates being connected to different ends of the web, respectively.
4. A rib node according to claim 3, wherein the side of the wing remote from the web is provided with a plurality of pegs.
5. The arch springing node of claim 3, wherein the pre-embedded steel further comprises a plurality of stiffening plates arranged along a transverse direction of the concrete column, the stiffening plates are arranged along an axial direction of the concrete column at intervals, and all the stiffening plates are arranged inside an area enclosed by four wing plates and connected with the web and the wing plates.
6. The arch springing node of claim 5, wherein each of said stiffening plates is divided by said web into four sub-stiffening plates, each of said four sub-stiffening plates having a through hole.
7. The arch springing node of claim 1, wherein a plurality of horizontal stiffening ribs are disposed between two of the pre-embedded steel sections, and both ends of each horizontal stiffening rib are connected to two of the pre-embedded steel sections respectively.
8. The arch foot node of claim 7, wherein a plurality of the horizontal stiffeners are provided with through holes.
9. The arch springing node of claim 7, wherein a plurality of vertical stiffening ribs are arranged between two pre-embedded profile steels, the vertical stiffening ribs are perpendicular to the horizontal stiffening ribs, and the vertical stiffening ribs are connected with the plurality of horizontal stiffening ribs.
10. The arch springing node of claim 1, wherein the top of the concrete beam is flush with the top end of the concrete column.
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| CN113463764A (en) * | 2021-04-30 | 2021-10-01 | 广东省建筑设计研究院有限公司 | Large-span steel-concrete arch truss structure for civil buildings and construction method thereof |
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| CN113463764A (en) * | 2021-04-30 | 2021-10-01 | 广东省建筑设计研究院有限公司 | Large-span steel-concrete arch truss structure for civil buildings and construction method thereof |
| CN113463764B (en) * | 2021-04-30 | 2023-01-10 | 广东省建筑设计研究院有限公司 | Large-span steel-concrete arch truss structure for civil buildings and construction method thereof |
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