KR20190131861A - Crane Plant Steel Structure having Vierendeel-Truss Seismic Force Resisting System - Google Patents

Abstract

Provided in the present invention is a crane steel frame factory structure with a Vierendeel-truss earthquake-proof structure, which can induce a plastic hinge at both ends of a Vierendeel panel and a lower end portion of an upper pillar in order to prevent damage on a crane pillar and a roof truss, and can guarantee an excellent deformation and energy dissipation capacity when an earthquake occurs, in order to maintain stability of a structure and a function of a crane factory. To this end, a crane steel frame factory structure with a Vierendeel-truss earthquake-proof structure according to an adequate implementation of the present invention is a crane steel frame factory structure, in which an upper pillar is installed while a pillar base unit is placed at an upper end of a crane pillar on the both sides, and a truss roof is provided to connect an upper end of the upper pillar to each other. Here, in a Vierendeel panel, from which a diagonal bracing cable is removed, and which is installed at a central portion of the truss roof, a Vierendeel upper chord member and a Vierendeel lower chord member having an identical cross section structure are installed. At the Vierendeel upper chord member and the Vierendeel lower chord member, Vierendeel upper and lower chord member plastic hinge units are formed to have a reduced cross section after being individually cut in a predetermined shape at an end portion. In addition, an upper pillar plastic hinge unit is formed at a lower end portion of the upper pillar, which is cut in a predetermined shape to have a reduced cross section. Therefore, when an earthquake occurs, the plastic hinge is simultaneously induced at the Vierendeel upper and lower chord member plastic hinge units and the upper pillar plastic hinge unit, such that an earthquake energy may be dissipated and the crane pillar may be prevented from being collapsed.

Description

Crane Plant Steel Structure having Vierendeel-Truss Seismic Force Resisting System}

The present invention relates to a virendil-truss seismic structural system of a steel plant structure in which a crane is installed between an upper pillar and a lower pillar, and in particular, energy dissipation is concentrated during an earthquake in a virendil panel by installing a virendil panel in the center of the truss roof. Steel frame with a virendil-trus seismic structure to intentionally adjust the strength of the upper pillar to protect the lower pillar (hereinafter referred to as the crane pillar) to support the crane. It relates to the plant structure.

The recent earthquake after the Gyeongju and Pohang earthquakes in the southeastern Korean Peninsula has become an undeniably effective threat in Korea. Accordingly, there is a need for concern and improvement on the seismic performance of factory structures that use long span cranes as one of the major industrial facilities. This has been raised steadily.

Most of the existing crane-installed plant structures are undefined systems that do not belong to any standard system under the current seismic standards, and it is not clear which structural elements are damaged in the event of an earthquake, and the failure mechanism (yield mechanism) is unclear. Do. As a result of the seismic analysis of the existing domestic truss roof factory structure that has been conventionally designed / constructed, plastic hinges are generated at the upper and lower pillar ends as shown in FIG. 1 to act as a so-called shear building. It can be seen that it shows a yield breakdown mode. Such a structure having a column yielding failure mode is not preferable because it has low seismic performance and thus does not exhibit ductility during an earthquake and may suddenly cause collapse of the entire structure.

According to current domestic steel plant plant design practices, truss roofs are generally adopted for the economics of roofing steel plant plants with a span of 30m to 40m. In the case of the lateral force resistance system applied to the current plant factory, the role sharing of the elastic and inelastic elements of the structure that resists most earthquakes is unclear, and the design is regarded as an undefined system that does not belong to any standard system of seismic standards. Therefore, only the strength and stiffness design is performed by selecting the reaction modification coefficient R = 3 without applying the seismic details. It is difficult to determine the adequacy of the design method when applied to the design of industrial buildings, and it is difficult to determine whether the structure maintains ductile behavior in the event of a earthquake because there is no information on seismic performance obtained as a result of the design. Can not.

On the other hand, capacity design is a design concept that is the basis of seismic resistance system such as special moment frame (SMF) and eccentric bracing frame (EBF) included in domestic earthquake resistance standards. Competency design is a design concept that clearly distinguishes elements that generate plastic hinges and those that maintain elasticity in the structure, so that only the parts where plastic hinges occur occur in inelastic deformation and energy dissipation. In case of seismic structure system based on capacity design, it is possible to secure the deformation capacity and stability of the entire structure by securing only the ductility of the plastic hinge.

In the case of the factory structure virendil-trus seismic structure to be proposed in the present invention can also be called a design method that can clearly define the occurrence position of the plastic hinge based on the concept of capacity design. The truss roof is protected by concentrating inelastic deformation in the center of the truss roof to prevent the collapse of the entire roof and inducing the crane column deformation to the upper column above the crane column.

Since the crane column is directly subjected to the large gravity load transmitted from the crane, when the plastic hinge is generated inside or exposed to a large lateral displacement, the P- △ secondary effect can cause fatal damage that affects the stability of the structure as a whole. have. If the safety of crane poles is a problem, it can cause major plant malfunctions, which is expected to cause great damage. Therefore, concentrating the earthquake damage to the space above the crane where the equipment is not arranged enables the plant to maintain its function and recover quickly. Since the actual earthquake losses of industrial facilities are mainly caused by indirect damages due to the stoppage of production and the interruption of production rather than the direct damages caused by the damage of buildings, it is economically important to have a destruction mechanism that can maintain the function even after the earthquake damages. Do.

As a background technology of the present invention, Korean Patent Registration No. 10-1642420 has been proposed, 'end reinforced steel structure.' It is a steel pillars provided vertically with a gap between each other, and the cheolgolbo connecting between the steel pillars, and one end at both sides of the lower end of the cheolgolbo is fixed to the steel column to support both lower ends of the cheolgolbo An end reinforcing steel frame structure comprising a compressive reinforcing material to reinforce the bearing capacity against the compressive load; One end at both sides of the upper cheolgolbo is fixed to the steel column, and further comprises a tensile reinforcing material to support the upper sides of the cheolgolbo to reinforce the strength of the tensile load occurring on both sides of the cheolgolbo, Reinforcement of the tensile loads on both sides of the upper surface ensures stability as well as reinforcement of seismic performance to reinforce brittle fracture.

However, in the background art, reinforcement of tensile load and brittle fracture of steel beams is realized, but a method of reducing damage of steel pillars, especially crane pillars, to earthquake loads is not proposed.

Korea Patent Registration No. 10-1642420

The present invention can maintain the stability of the structure and the function of the crane factory by inducing plastic hinges on both ends of the virendil panel and the lower end of the upper column to prevent damage to the crane pillar and roof truss and to secure excellent deformation and energy dissipation capacity during an earthquake. It is an object of the present invention to provide a crane steel plant structure having a virendil-truss seismic structure.

According to a preferred embodiment of the present invention, the crane steel frame factory structure having a virendil-truss seismic structure, the upper pillar is provided with a plinth at the upper end of the crane pillar on both sides, the truss roof interconnecting the upper end of the upper pillar In the crane steel plant structure consisting of, the berendil panel with sand material removed from the center of the truss roof is installed berendil upper choir and berendil lower chord of the same cross-sectional structure, respectively A virendil upper and lower chord plastic hinge portion, which is cut in a constant shape toward the end side and whose cross section is reduced, is formed; The upper pillar plastic hinge is cut in a constant shape at the lower end of the upper pillar and the cross section is reduced, and the plastic hinge is induced at the same time as the upper and lower plastic hinges at the upper and lower virendils when the earthquake arrives. By dissipating is characterized in that the collapse of the crane pillar is suppressed.

In addition, the virendil upper and lower chords and the vertical member and the upper pillar is made of a seismic steel or a resistance point steel having an H cross section, the crane pillar is characterized in that made of high strength steel.

In addition, the joining of the virendil upper and lower chords and the vertical member is a steel joint capable of transmitting a moment through the joint steel member disposed and protruded in the vertical direction, and is also strongly joined to the truss section of the truss roof.

In addition, the span where the virendil panel is installed is characterized in that it is within 10% of the total span of the truss roof.

Crane steel frame factory structure having a virendil-truss seismic structure of the present invention, by concentrating energy dissipation in the virendil panel during the earthquake and minimizing the deformation of other structural elements to prevent plant collapse and minimize damage to the plant to minimize the function of the crane plant I can keep it. In addition, it is easy to maintain and repair because only the virendil panel needs to be replaced after an earthquake by focusing deformation on the virendil panel part.

The following drawings, which are attached in this specification, illustrate the preferred embodiments of the present invention, and together with the detailed description thereof, serve to further understand the technical spirit of the present invention. It should not be construed as limited.
Figure 1 is a schematic diagram of the modification of the conventional earthquake crane steel structure factory structure.
Figure 2 is a schematic diagram showing the deformation of the earthquake crane crane structure according to the present invention.
Figure 3a and 3b is a schematic diagram of the experimental diagram for the seismic performance verification of the virendil panel and its repeatability.
4A and 4B are conceptual diagrams of capacity design of a virendil-truss seismic structure system.
Figure 5 is a block diagram of a crane steel structure factory structure according to an embodiment of the present invention.
6 is a perspective view of the center of the truss roof shown in FIG.
7 is a perspective view of the lower end of the upper column shown in FIG.

In the following the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings, but the embodiments presented are exemplary for a clear understanding of the present invention is not limited thereto.

First, the present invention is to install a virendil panel in the center of the truss roof as shown in Figure 2 to induce plastic hinges on both ends of the virendil upper and lower chords, and to prevent the yield of all other structural elements. The upper and lower chords and vertical members of the virendil panel are secured structurally by rigidly connecting the upper and lower chords and the vertical members by applying an extended end plate bolted moment connection. Unlike neighboring truss members exhibiting dominant axial forces, the up-and-down chords of the birendil panels without abdominal members exhibit the behavior of bending. As the lateral force increases, the upper and lower chords of the virendil panel are subjected to bending stress and yield to form a plastic hinge, and four plastic hinges formed at the upper and lower chords of the virendil panel rotate to accommodate the deformation of the structure. At this time, since the virendil panel is exposed to repeated large deformation after yielding, a material having high toughness should be used, and yielding strength is relatively low because it has to yield faster than the surrounding members. Therefore, seismic resistant steel and resistance point steel are suitable for use as virendil beams.

Even after the plastic hinge is produced in the virendil panel, the structural elements other than the virendil panel must remain elastic. Therefore, it is effective to use high strength steel or steel with higher yield strength than non-rendil panels for trusses and truss members. This minimizes damage to the entire structure by concentrating deformation and damage to the virendil panel, and suppresses unstable failure modes such as truss members and buckling of columns. In addition, in order to clarify the position of the plastic hinge, a flange cut section (RBS) may be applied to the upper and lower ends of the virendil panel.

Secondly, the deformation of the crane pillar and the plastic hinge of the lower portion are guided to the upper pillar above the crane pillar to minimize the damage of the crane pillar. Since the crane column is directly subjected to a large gravity load transmitted from the crane, when the plastic hinge is generated inside or exposed to a large lateral displacement, the secondary effect may cause a fatal damage that affects the stability of the structure as a whole.

Deformation and plastic hinges are induced in the upper column by performing performance-based design or by cutting the upper column flange.

To do this, design according to the three-step design procedure.

The first stage is to carry out the stiffness and strength design of the factory structure according to the steel structure design section 0701-0712 of KBC 2016. At this time, the reaction correction coefficient R applied to the design earthquake load is applicable to 6-7.

In the second step, the shear force and plastic moment are calculated in consideration of the excess strength due to the hysteretic behavior occurring in the virendil panel plastic hinge. After applying the plastic hinge shear force and plastic moment to the design load, it is examined whether the roof truss designed in step 1 is elastic (see Fig. 4a).

In the third step, nonlinear static analysis (pushover analysis) is carried out to adjust the Demand-Capacity Ratio (DCR) value, which is the seismic performance indicator, against the crane pillar to protect the crane pillar. Finally, the adjusted design is verified through seismic performance evaluation (see Fig. 4b).

<Example>

Crane steel frame factory structure 10 according to the present embodiment, the upper pillars 14, 14a are provided with a plinth on the upper end of the crane pillars 12, 12a as shown in FIG. It also consists of a truss roof (16) interconnecting the upper ends of the upper pillars (14, 14a).

Here, the crane columns (12, 12a) is applied to a lattice column or composite column having a large resistance to axial / lateral load. Since the upper pillars 14 and 14a do not support the crane load, a single member such as H-shaped steel is usually used. At this time, the crane posts 12 and 12a should be adjusted in the design process so as to be protected when the yield mechanism is expressed. (See FIG. 4) A virendil panel is installed at the center of the truss roof 16. The virendil panel consists only of the upper chord 18, the lower chord 18a, and the vertical member 18b. If the virendil panel is too long, the stiffness and strength are lowered so that the virendil panel span is within 10% of the total span of the roof truss. In addition, the long side does not exceed 1.5 times the short side for the morphenyl panel morphological stability to be close to the square shape. In addition, the plastic hinge points 181 and 181a during the earthquake can be more clearly formed by cutting the virendil panel upper and lower current ends in a predetermined shape to reduce the cross section.

The virendil plastic hinge portions 181 and 181a are formed by grooves cut in a half moon shape in the present embodiment, but are not limited thereto. The truss section 16 includes a section except for the virendil panels 18, 18a, and 18b, that is, the upper chord 161, the lower chord 162, and the yarn 163. In this case, the virendil upper chord 18 and the lower chord 18a may be strongly joined to the virendil vertical material 18b through the joint steel members 17 and 17a disposed in the vertical direction with H-shaped cross sections at both ends. . In addition, by using the joint steel members 17 and 17a, the virendil upper chord 18 and the virendil lower chord 18a can be easily structurally connected to the truss upper chord 161 and the lower chord 162. have. Further, as shown in FIG. 7, upper pillar plastic hinge portions 141 and 141a which are cut in a predetermined shape and have a reduced cross section are formed at the lower ends of the upper pillars 14 and 14a. The upper pillar plastic hinge portions 141 and 141a are formed by grooves cut in half-moon shapes in this embodiment, but are not limited thereto.

The crane pillars 12 and 12a, which become elastic elements, are made of high strength steel, and the inelastic elements virendil upper and lower chords 18 and 18a and the vertical member 18b and the upper pillars 14 and 14a are made of seismic steel or The use of a resistive spot steel facilitates yielding of inelastic elements. In addition, as a result of performing the Virendil panel reduction experiment using the resistive recovery point steel (Fy = 160MPa) as shown in Figure 3, it can be confirmed that the excellent energy dissipation capacity of the special moment frame (R = 8) or more.

As described above, the present invention concentrates deformation on the virendil panel having excellent energy dissipation ability, and other structural elements including the crane columns 12 and 12a maintain elasticity to suppress the collapse of the crane steel plant structure 10 to prevent damage. Minimized and excellent deformation capacity can be secured.

In addition, by guiding the plinth hinge to the upper pillars 14 and 14a above the crane pillars 12 and 12a, it is possible to effectively maintain the stability of the structure and the function of the crane plant even in the event of a strong earthquake and to maximize the recovery ability in the event of damage. Can be. So far, the present invention has been described in detail with reference to the presented embodiments, but those skilled in the art may make various modifications and modifications without departing from the technical spirit of the present invention with reference to the presented embodiments. will be. The invention is not limited by the invention as such variations and modifications but only by the claims appended hereto.

17,17a: joint steel member
18: Virendil Prize
18a: Virendil High Current
18b: Virendil Vertical
181,181a: firing hinge of virendil upper and lower current
14,14a: upper pillar
141,141a: upper pillar plastic hinge

Claims (4)

Crane steel frame factory consisting of a truss roof (16) having upper pillars (14, 14a) having a plinth on the top of the crane pillars (12, 12a) on both sides and interconnecting the upper ends of the upper pillars (14, 14a) In the structure,
A virendil top chord 18 and a virendil bottom chord 18a having the same cross-sectional structure are installed as a virendil panel in which the sand material is removed from the center of the truss roof 16, and the virendil top chord 18 and the virendil Virendil upper and lower chord plastic hinge portions 181 and 181a are formed in the lower chord 18b, respectively, cut into a predetermined shape toward the end side and the cross section thereof is reduced;
The upper pillar plastic hinge portions 141 and 141a, which are cut in a predetermined shape at the lower ends of the upper pillars 14 and 14a and whose cross section is reduced, are formed.
When the earthquake arrives, the plastic hinges are induced at the upper and lower firing hinges 181 and 181a and the upper pillar firing hinges 141 and 141a at the same time to dissipate the seismic energy so that the collapse of the crane posts 12 and 12a is suppressed. Crane steel structure having a virendil-truss seismic structure, characterized in that one. The method of claim 1,
Virendil upper and lower chords (18, 18b), the vertical member (18b) and the upper column (14, 14a) is made of seismic steel or resistance point steel having an H cross section, crane poles (12, 12a) is a high-strength steel Crane steel frame factory structure having a virendil-truss seismic structure, characterized in that the production. The method of claim 1,
The joining of the virendil upper and lower chords 18 and 18a and the vertical member 18b is a steel joint capable of transmitting moments through the joint steel members 17 and 17a arranged and protruded in the vertical direction, and the truss roof 16 Crane steel frame factory structure having a virendil-truss earthquake-resistant structure, characterized in that it is also strongly joined to the truss section. The method of claim 1,
The span where the virendil panel is installed is within 10% of the total span of the truss roof 16. The crane steel plant structure having the virendil-truss seismic structure.

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