KR20230077123A - Composite panel for structural explosion-proof reinforcement and its installation structure - Google Patents

Abstract

The present invention relates to a composite panel for explosion-proof reinforcement of a structure and an installation structure thereof, which can be installed on the wall of an existing building as well as a new building, and can prevent additional damage caused by fragments by attenuating the energy of explosion and suppressing the destruction of the structure. It relates to a composite panel for explosion-proof reinforcement of a structure and its installation structure.
To this end, in the present invention, "In a composite panel for explosion-proof reinforcement of a structure constructed on the front surface of a wall to reinforce the explosion-proof performance of a structure, a shock absorber disposed closely to the wall and made of foamed synthetic resin; a high-toughness panel disposed on the front surface of the impact absorbing material and made of fiber-reinforced ultra-high-performance concrete (UHPC); and a synthetic resin reinforcing sheet disposed on at least one of the front or rear surface of the high-toughness panel.

Description

Composite panel for structural explosion-proof reinforcement and its installation structure}

The present invention relates to a composite panel for explosion-proof reinforcement of a structure and an installation structure thereof, which can be installed on the wall of an existing building as well as a new building, and can prevent additional damage caused by fragments by attenuating the energy of explosion and suppressing the destruction of the structure. It relates to a composite panel for explosion-proof reinforcement of a structure and its installation structure.

Recently, as problems caused by environmental pollution increase, countries around the world are promoting policies to reduce the use of fossil fuels and develop and apply eco-friendly energy by accelerating movements for decarbonization. Accordingly, regulations on vehicles powered by fossil fuels have been strengthened, resulting in a decrease in demand for vehicles powered by fossil fuels and an increase in demand for vehicles powered by eco-friendly energy such as electricity and hydrogen. The share of electric vehicles in the market is increasing exponentially, and the share of hydrogen vehicles is also continuously increasing. In addition, as environmental regulations are strengthened around the world, the demand for vehicles using eco-friendly energy such as electric vehicles and hydrogen vehicles is expected to increase further in the future.

Eco-friendly vehicles such as electric vehicles and hydrogen vehicles require dedicated charging stations that can be recharged with electricity or hydrogen unlike fossil fuel vehicles that are refueled at gas stations. Efforts are being made to increase the installation rate of electricity and hydrogen-only charging facilities and charging stations and to expand related infrastructure.

However, hydrogen vehicle charging stations require a storage container for storing liquefied hydrogen, and as electric vehicles and hydrogen vehicles use large-capacity batteries for electric charging, there is a problem in that the risk of hydrogen explosion and battery explosion increases. In particular, since electric and hydrogen-only charging stations are installed close to densely populated residential areas such as downtown areas or parking lots in residential areas, serious human casualties may occur in the event of an explosion. Recently, damage caused by explosion accidents of lithium-ion batteries built into electric vehicles is continuously increasing, and concerns about explosion accidents of hydrogen tanks are increasing, such as the cases of explosion accidents at hydrogen charging stations in Norway Uno-X station and explosion accidents in Gangneung hydrogen tanks. there is.

Among them, when a large amount of compressed liquefied gas such as a hydrogen tank or an LNG tank explodes, the damage is very extensive and serious human casualties may occur.

When an explosion occurs, heat and shock due to the explosion are transmitted. In the case of a large concrete structure constructed by calculating a static load, a local failure behavior occurs when an extreme load generated by an explosion is received.

When an explosion accident suddenly occurs in an urban area or a parking lot in a residential area, the building structure is destroyed by the extreme load generated in a minute, and in serious cases, the entire structure collapses, resulting in large-scale human casualties. In addition, additional human life and property damage may occur due to fragments scattered at high speed from buildings destroyed by the impact of the explosion.

Recently, in order to protect facilities with a risk of explosion, a method of adjusting the thickness of the concrete wall and the spacing of reinforcing bars is being used, and the structure to be reinforced is constructed as a reinforced concrete explosion-proof wall of 25 to 30 cm or more, and the structure is When reinforcing, a method of adding reinforced concrete members or steel plate members with a thickness of 10 to 20 cm or more is adopted. However, the method of increasing the thickness of the concrete wall increases the load of the structure, limits the installation height of the building, reduces the usable space, and excessively increases the construction cost, which is inefficient. In addition, the above standards are explosion-proof standards for general low-pressure explosions. In the case of explosion-proof standards for high-pressure explosions such as bunkers in bank facilities or military facilities, explosion-proof walls are constructed with reinforced concrete structures up to a wall thickness of around 1 m to prevent explosions and It is difficult to apply the same explosion-proof standards for high-pressure explosions to general residential buildings.

As described above, in case of applying a method of increasing the wall thickness of an existing building belonging to the expected explosion radius of a charging station in order to respond to a high-pressure explosion, it is difficult to secure additional space for increasing the wall thickness, and rather, as the load increases, the load on the existing building It is difficult to actually apply the method of increasing the thickness of an existing building because there is a risk of deformation of the structure due to the increase.

Therefore, it has explosion-proof performance that effectively absorbs explosion pressure while minimizing the increase in wall thickness and load, and has excellent penetration resistance performance to protect the structure against direct blows caused by explosions, and flying objects that have fallen off the building due to explosions. There is a need for an explosion-proof member that can be applied to existing buildings while preventing secondary damage caused by the explosion.

In this regard, according to Korean Patent Registration No. 10-1738823 "Explosion-proof Panel Including Foamed Aluminum Sheet" as a prior art document, a high-corrosion-resistant steel sheet having a tensile strength of 410 to 490 MPa or a high-strength steel sheet having a tensile strength of 700 to 760 MPa A central bearing plate formed of; A pair of foamed aluminum plates respectively disposed on both sides of the central bearing plate; And a pair of high corrosion-resistant steel plates having a tensile strength of 410 to 490 MPa or a pair of tensile strengths of 700 to 760 MPa, respectively, disposed on the opposite side to the side on which the central bearing plate is disposed among both sides of the pair of foamed aluminum plates. It includes an outer plate formed of a high-strength steel plate, and the central bearing plate and the outer plate are made of the same high corrosion-resistant steel plate or high-strength steel plate, between the central bearing plate and a pair of foamed aluminum plates, and the pair of To provide an explosion-proof panel including a foamed aluminum plate, characterized in that a ceramic adhesive layer in which a ceramic and an adhesive are mixed is interposed between the foamed aluminum plate and the outer plate, to provide a lightweight, shock-absorbing, heat-resistant and durable foamed aluminum plate Explosion-proof panels are provided.

However, the prior art constitutes an explosion-proof panel including a central bearing plate using a high corrosion-resistant steel plate or a high-strength steel plate and an aluminum plate. If the high corrosion resistance steel sheet is applied to the entire wall, there is a possibility that the overall construction cost will increase.

In addition, Korean Patent Registration No. 10-1593566 "Explosion-proof wall using a panel unit with bulletproof and shock absorbing function" of the present invention has a sandwich structure in which an aluminum foam panel made of foamed aluminum and a bulletproof plate are laminated between two shell plates. A plurality of bulletproof-explosion-proof panel units, which have bulletproof and shock-absorbing functions, are attached to the front of the back plate made of steel plate, and a front plate is installed in front of the bulletproof-explosionproof panel unit in thickness. It has a configuration arranged at intervals in the direction, exhibits excellent explosion-proof performance by efficient shock absorption and excellent bullet-proof performance against bullets, etc., and relates to an explosion-proof wall that can be quickly built by rapid assembly. Similarly, the application of expensive aluminum panels and foamed aluminum increases the manufacturing cost, and if the material and shape of the material is different from the existing concrete wall and is applied for reinforcement to the existing building, there is a concern that the urban aesthetics may be hindered.

As described above, the trend of existing explosion-proof technology mainly used composite panels that mixed aluminum panels and foamed aluminum, which have a predetermined explosion-proof effect due to their excellent shock absorption capacity, mechanical strength, and heat resistance, but the manufacturing cost is high, and buildings composed of existing concrete It is heterogeneous and is limited to special facilities such as military facilities or ammunition depots, and it is difficult to apply to existing buildings. In addition, since aluminum has low self-stiffness, it is essential to alloy it with other metals or to reinforce it with high-strength steel sheets in order to obtain the strength necessary to reduce the explosive force, so there is a disadvantage in that the manufacturing cost increases. In addition, since steel and aluminum must be processed, it is difficult to change the size or shape according to the situation of the site because it is constructed in a way that is manufactured in a factory, transported, and constructed on site.

Therefore, it can be constructed on existing concrete walls, has excellent explosion-proof performance, and has excellent penetration resistance, thereby minimizing damage to existing walls, suppressing the generation of debris, and can be constructed quickly and flexibly according to the situation at the site. Development of explosion-proof reinforcing panels that can be constructed is required.

1. Republic of Korea Patent Registration No. 10-1738823 "Explosion-proof panel including foamed aluminum plate" 2. Republic of Korea Patent Registration No. 10-1593566 "Explosion-proof wall using bulletproof and shock absorbing panel unit" 3. Republic of Korea Patent Registration No. 10-1250903 "Composite explosion-proof wall of aluminum foam panel and concrete plate, its construction method and explosion-proof structure using the same" 4. Republic of Korea Patent Registration No. 10-1895027 "Bulletproof, explosion-proof and electromagnetic wave blocking panel" 5. Republic of Korea Patent Publication No. 10-2016-0137759 "Composite panel manufacturing technology for protection and explosion-proof reinforcement using composite fibers and adhesives" 6. Korean Patent Publication No. 10-2018-0035322 "Aramid paper composite for bulletproof panel and bulletproof panel including the same"

The present invention has excellent explosion-proof performance without degrading the characteristics and aesthetics of existing reinforced concrete buildings, and has excellent penetration resistance to minimize damage to existing walls, thereby suppressing the generation of debris, minimizing the increase in wall thickness and weight, and The purpose is to develop a composite panel for structure explosion-proof reinforcement and its installation structure that can be constructed quickly and has excellent formability and can be flexibly constructed according to site conditions.

In order to solve the above problems, in the present invention, "in the composite panel for explosion-proof reinforcement of a structure constructed on the front surface of a wall to reinforce the explosion-proof performance of the structure, a shock absorber disposed closely to the wall and made of foamed synthetic resin; and a high-toughness panel disposed on the front surface of the shock absorber and made of fiber-reinforced ultra-high-performance concrete (UHPC).

In addition, a reinforcing sheet made of synthetic resin disposed on at least one of the front or rear surface of the high-toughness panel may be further included.

In addition, the reinforcing sheet may be molded of glass fiber reinforced plastic (GFRP).

In addition, the impact absorbing material has a density of 60 to 100 kg/m ³ , a tensile strength of 10 to 20 kgf/cm ³ , an elongation of 10 to 30%, a compressive stress of 4 to 8 kgf/cm ³ at 10% compression, and compression at 25% compression. Stress 5~10 kgf/cm ³ , Compressive stress at 50% compression 6~12 kgf/cm ³ can be formed as

In the present invention, "an installation structure of a composite panel for explosion-proof reinforcement of a structure, in which two or more through-holes are formed at the edge of the composite panel, and the head of a connecting material embedded in a wall passes through the through-hole to the front of the composite panel. It protrudes into and provides a composite panel installation structure characterized in that it is constructed by fastening a fixture to the head of the connecting member.

The composite panel for explosion-proof reinforcement of a structure according to the present invention is applicable to the wall of an existing building, has high integrity with the reinforced concrete wall, and minimizes the increase in the thickness and weight of the structure, thereby reducing the load burden of the existing building and minimizing the reduction in the exclusive area of the building. can do.

In addition, it has excellent explosion-proof performance by applying a composite structure in which materials with different physical properties are laminated, and has excellent penetration resistance to minimize damage to existing walls, thereby suppressing the generation of debris and preventing additional human life and property damage.

In particular, by inserting and fastening the composite panel for explosion-proof reinforcement of a structure according to the present invention to a connecting material on a wall of a building, it is possible to reduce installation time and improve explosion-proof performance by effectively dispersing impact.

[Figure 1] to [Figure 3] shows embodiments of the structure of the composite panel for explosion-proof reinforcement of structures according to the present invention.
[Figure 4a] to [Figure 4b] shows the construction process of the composite panel installation structure for structure explosion-proof reinforcement according to the present invention.

In the present invention, in the composite panel (1) for explosion-proof reinforcement of a structure constructed on the front surface of a wall (W) to reinforce the explosion-proof performance of a structure, it is placed in close contact with the wall (W) and shock mitigation made of foamed synthetic resin ash (10); a high toughness panel 20 disposed on the front surface of the impact absorbing material 10 and made of fiber-reinforced ultra-high performance concrete (UHPC); and a synthetic resin reinforcing sheet 30 disposed on at least one of the front or rear surfaces of the high-toughness panel 20.

In this specification, the direction in which bombs or bullets fly from the existing wall (W), that is, the direction in which the impact is first applied is referred to as 'front' or 'surface', and the opposite side is referred to as 'back'. . In addition, the direction of the wall (W) is referred to as the inside, and the direction opposite to the wall (W) is referred to as the outside.

The impact absorbing material 10 may be formed of any one or more of foamed plastics capable of foam molding. A single type of raw material may be used, or more than one raw material may be mixed and applied in order to secure predetermined strength and ductility.

Since the foamable synthetic resin densely disperses gas inside the molten synthetic resin to form a foamed or porous space, it is lightweight and has excellent insulation, cushioning and shock absorption compared to solid type synthetic resin. .

The shock absorbing material 10 is formed of a synthetic resin capable of foam molding, and includes expanded polypropylene (EPP), expanded polyethylene (EPE), expanded polyurethane (EPU), expanded polyolefin (EPO), expanded polystyrene (EPS), and expanded foam. It may be made of any one or more of phenolic resin (EPF), expanded polyvinyl chloride (PVC), expanded urea resin (EUF), expanded silicone (ESI), expanded polyamide (EPI), and expanded melamine resin (EMF).

In particular, expanded polypropylene (EPP) has excellent heat resistance with a melting point of 165°C, maintains buffering properties even at -30°C, so there is little heat shrinkage due to temperature changes, and has excellent thermal insulation, adhesion, stiffness, resilience, oil resistance, and chemical resistance. It is excellent, and PP is chemically stable, so there is little harmful gas generation, so it is suitable for exterior materials of buildings and explosion-proof, and is therefore preferable as a raw material for the shock absorbing material 10. In addition, expanded polypropylene (EPP) is environmentally friendly as it can be re-molded after grinding.

In addition, the impact absorbing material 10 has a density of 60 to 100 kg/m ³ , a tensile strength of 10 to 20 kgf/cm ³ , an elongation of 10 to 30%, and a compressive stress of 4 to 8 kgf/cm ³ at 10% compression, 25 Compressive stress at % compression 5~10 kgf/cm ³ , Compressive stress at 50% compression 6~12 kgf/cm ³ It is preferable to form. The shock absorbing material 10 is foamed synthetic resin to have an apparent density of 60 to 100 kg/m ³ belonging to a medium-density to high-density range, and a tensile strength of 10 to 20 kgf/cm ³ , The elongation is formed in the range of 10 to 30%, so it has a higher density and less strain than general foamed synthetic resins, so it can lower the probability of destruction by impact. That is, when the shock absorbing material 10 is formed with the above physical properties, as the deformation caused by the explosive force decreases, the explosion-proof performance can be maintained for a long time, the transmission time of the impact force can be delayed, and the impact force mitigation effect can be maximized.

When the elongation rate is lower than the above value, the toughness is lowered and it is difficult to effectively relieve the explosive force, and when it is higher than the above value, the required value of compressive force and tensile force cannot be expressed.

The impact mitigating material 10 formed as described above has a high impact damping ratio, delays the transmission time of the impact force due to the explosion, increases the transmission time of the impact force, and relieves the compressive stress wave to secure an impact mitigation effect such as that of the hollow layer. can Since the impact force is proportional to the force and inversely proportional to the time, the impact force can be alleviated as the arrival time of the shock wave increases due to the delayed delivery time. In addition, since the impact is dispersed and transmitted during the delay time, the member that finally receives the impact receives the total impact force by dividing it according to time, so that the impact force is dissipated.

In this way, the impact absorbing material 10 indirectly bears the explosion load and at the same time dissipates the residual explosion impact force transmitted through the high toughness panel 20 and the reinforcing sheet 30, and the high toughness panel 20 And by minimizing the deformation of the reinforcing sheet 30, the impact force transmitted to the existing building is alleviated, and the laminated member such as the high-toughness panel 20 collides with the wall W of the existing building so that the wall W is not destroyed. can protect you from it. In addition, the shock absorbing material 10 made of high ductility by foam can further increase the effect of absorbing stress due to the toughness of the high toughness panel 20 through a complex action.

The shock absorbing material 10 may be formed to a thickness of 20 to 40 mm to secure a thickness for separating the wall W and the high-toughness panel 20 and mitigating impact.

The high-toughness panel 20 is disposed on the front surface of the impact absorbing material 10 and may be made of fiber-reinforced ultra-high performance concrete (UHPC). Ultra high performance concrete (UHPC) is characterized by ultra-high strength and high toughness with a compressive strength of 120 MPa or more, and admixtures such as water reducing agents, expanding agents, and shrinkage reducing agents are mixed with water, binders, coarse aggregates and fine aggregates to increase the activity of hydration and increase the amount of shrinkage. It is a concrete structured to realize ultra-high strength through control, etc.

In particular, the high toughness panel 20 of the present invention can improve toughness by reinforcing ultra high performance concrete (UHPC) with fibers. As the reinforcing fibers, any one or more of steel fibers, synthetic resin fibers, and composite fibers may be applied.

At this time, the reinforcing fibers are included in the ultra high performance concrete in an amount of 1.5 to 2.0 vol%, so that sufficient toughness can be exhibited within a range that does not degrade the physical properties of the ultra high performance concrete.

The high-toughness panel 20 has the effect of reducing the shock wave through the absorption and dispersion of stress due to the cross-linking action of the high-toughness and reinforcing fibers to control the explosion load and consequently to attenuate the explosion pressure and thermal energy.

The high toughness panel 20 may be formed to a thickness of 40 to 60 mm in order to minimize weight increase while securing sufficient rigidity and ductility to reduce explosion and absorb explosive force.

The reinforcing sheet 30 may be formed of a synthetic resin material sheet disposed on at least one of a front surface or a rear surface of the high toughness panel 20 .

The reinforcing sheet 30 may be molded into a sheet form by incorporating reinforcing fibers to reinforce tensile and compressive forces by mixing a reinforcing material with a synthetic resin having ductility. In particular, it is preferable to incorporate glass fibers that withstand high temperatures generated by explosion, have low heat absorption, and have excellent tensile strength and tensile modulus of elasticity.

Glass fiber has an elongation of less than 3%, so it has excellent dimensional stability and suppresses the penetration of fragments generated when the structure is destroyed by an explosion. In addition, since it is an incombustible fabric made of inorganic materials, it has excellent heat resistance and quickly dissipates heat, so it is possible to prevent deterioration of strength due to deterioration of the structure due to explosion heat.

The reinforcing sheet 30 has an effect of dissipating energy due to explosive force and attenuating tensile stress to reinforce the tensile force of the composite panel and reduce penetration failure.

In order to reinforce the tensile force and resist penetration failure as described above, the reinforcing sheet 30 is preferably formed with a tensile strength of 280 to 300 MPa, a flexural strength of 230 to 250 MPa, and a flexural modulus of 11 to 13 Gpa.

The reinforcing sheet 30 may be formed to a thickness of 3 to 10 mm in order to secure sufficient ductility and fire resistance. When it is formed with a thickness of less than 3 mm, the mixing ratio of fibers is low and it is difficult to secure sufficient ductility and fire resistance performance, and when it exceeds 10 mm, the load of the member increases and the shock absorption capacity may decrease.

[Figure 1] shows an embodiment in which the reinforcing sheet 30 is disposed on the rear surface of the high-toughness panel 20, and [Figure 2] shows that the reinforcing sheet 30 is disposed on the front surface of the high-toughness panel 20. 3 is an embodiment in which the reinforcing sheet 30 is disposed on the front and rear surfaces of the high-toughness panel 20.

As described above, even when the reinforcing sheet 30 is disposed on either the front or rear surface of the high-toughness panel 20, the predetermined performance is exhibited, and in a situation where more performance of the reinforcing sheet 30 is required, the Reinforcing sheets 30 may be disposed on the front and rear surfaces of the high-toughness panel 20 .

Hereinafter, the derivation process and technical background of the technology until the technology of the explosion-proof reinforcement composite panel 1 for structures of the present invention is derived will be described in detail with specific tests and examples.

1. Technology Derivation Process

According to the research results of the applicant, the concrete destruction mechanism by the direct impact force of the explosion or the flying object that scatters at high speed due to the explosion is as shown in [Reference Figure 1] below.

[Reference Figure 1] Schematic diagram of concrete destruction mechanism according to blast impact

When an impact is applied to the front of the concrete, the front of the wall (W) is destroyed by the impact and penetrates inward, a compression wave is generated from the front to the back, and the generated compression wave is reflected from the back of the concrete to form a tensile wave. form At this time, the tensile strain caused by the tensile wave and the stress caused by the compressive wave act in combination, and the back surface of the concrete is destroyed and peeled off.

When an explosion occurs according to the concrete destruction mechanism, the front and rear surfaces of the wall W are simultaneously destroyed, reducing the stiffness of the building wall W or pillar, and the structure may rapidly collapse. In particular, it was confirmed that the back separation area generated in the wall (W) by the explosion impact was formed wider than the front penetration area, and when examining the explosion-proof performance, the explosion-proof performance for the back destruction as well as the front penetration was reviewed. did

The main cause of backside failure is that the compressive and tensile waves generated by the impact reach the backside, and the explosion-proof panel absorbs or dissipates the impact force to suppress the transmission of the impact force to the backside of the wall (W). most effective in suppressing

Therefore, the inventors of the present invention conducted long-term research on a structure for effectively absorbing or dissipating shock waves transmitted to the rear surface of the wall (W) while resisting the impact force transmitted directly to the wall (W), An explosion-proof panel with a composite structure consisting of a high-toughness panel (20) made of ultra-high-performance concrete and an impact absorbing material (10) made of foamed synthetic resin was developed.

In more detail, it was confirmed that the rate of increase in the explosion-proof performance according to the increase in the strength of the explosion-proof panel was negligible in the research process conducted by the inventor, and the increase in the thickness and toughness of the member clearly increased the explosion-proof performance. However, if the thickness of the member is continuously increased, the load of the structure is increased and the exclusive area is reduced. Therefore, research was conducted in the direction of improving the explosion-proof performance by increasing the toughness within the range of minimizing the increase in the thickness of the member. In order to increase the toughness of the members and reduce the amount of impact, it was confirmed that the composite panel to which the ultra-high performance concrete with high toughness was secured and the impact absorbing material (10) with excellent resilience and buffering property was applied had excellent explosion-proof performance, and the composite panel An experiment was conducted to find the optimal arrangement to increase the explosion-proof performance.

In order to confirm the effect of the composite panel 1 for structure explosion-proof reinforcement provided by the present invention, the high-toughness panel 20 is placed in close contact with the front surface of the wall W, and the impact absorbing material 10 is placed on the front surface. The panel test specimen 1 and the impact absorbing material 10 are placed in close contact with the front surface of the wall (W), and the panel specimen 2 in which the impact absorbing material 10 is disposed on the front side is manufactured to conduct a comparative test on the explosion-proof performance. conducted. The high toughness panel 20 is a component that actually reduces the explosive force and absorbs the compressive force, and the impact absorbing material 10 is a component that mitigates the impact force while delaying the transmission time of the impact force. The explosion-proof performance of each was evaluated by changing the arrangement order.

Panel test specimen 1 is configured so that the impact caused by the explosion first reaches the high-toughness panel 20 and then the impact force of the high-toughness panel 20 is transmitted to the impact absorbing material 10, and panel specimen 2 is configured so that the impact caused by the explosion It reaches the impact absorbing material 10 first, reduces the initial impact force, delays the time for the impact energy to reach the rear surface, and receives the reduced impact force from the high toughness panel 20.

In order to carry out the above test, the inventor of the present invention conducted the experiment by assuming a state in which an extreme load is concentrated in a local area. If the resistance to local impact is excellent, it will be apparent that the resistance to impact force distributed over a certain range and transmitted as a surface load is also excellent.

To this end, the impact resistance performance was measured by launching a steel impactor at high speed and colliding with the panel test specimen, and the specifications of the impact resistance performance evaluation device are shown in Reference Figure 2 below.

The test was conducted by launching a 70 g flying object at the speed of sound (=340 m/s). Explosion-proof performance was evaluated by colliding at the maximum speed of 340 m/s, which is the maximum speed of the collision tester shown in Reference Figure 2 below. 340 m/s is used as a standard for the impact of a storm that occurs from the center of an explosion to the surroundings in the event of a bullet impact test or an explosion.

[Reference Figure 2] Impact resistance performance evaluation device

The panel test specimen is attached to the front of the structure for measuring impact force, and when the spherical collider launched from the impact tester of [Reference Figure 2] collides with the panel specimen, the impact force reaching the structure for measurement located on the back of the panel specimen is measured. Thus, the explosion-proof performance of the panel test specimen was evaluated.

The structure for measurement uses a steel plate in order to accurately measure the impact force. Since it is difficult to accurately measure the impact force of a typical concrete wall (W) due to the basic shock absorption capacity of the concrete structure, a steel plate was placed on the back of the panel test body to transmit the impact force without attenuation.

In order to measure the change in impact force according to the distance away from the impact point, as shown in [Reference Figure 3] below, an impact gauge was installed at 25 mm intervals to measure the impact at each location. An impactor collided with point 1 in [Reference Figure 3], and the impact force within a 100 mm interval in all directions from the point of impact was measured.

The high-toughness panel 20 used in the test was formed to have a thickness of 50 mm and the impact absorbing material 10 to have a thickness of 30 mm.

[Reference Figure 3]

[Reference Figure 4]

[Reference Figure 4] shows the process of installing a measuring gauge and forming a panel test body in the process of conducting the test.

The experimental results for the test were measured as strain over time from the impact of the flying body, and the following [Reference Figure 5] and [Reference Figure 6] are time-strain graphs according to impact force.

The following [Reference Figure 5] is a time-strain graph of panel test specimen 1, and [Reference Figure 6] is a time-strain graph of panel specimen 2. On the vertical axis, with the starting point 0 as the center, a positive number (+) represents the strain caused by the compression wave, and a negative number (-) represents the strain caused by the tensile wave.

[Reference Figure 5]

[Reference Figure 6]

Referring to [Reference Figure 5] and [Reference Figure 6], it is confirmed that both graphs suppress the arrival of the shock wave for a certain time (delay time) from the time when the shock occurs. As shown in the graph, except for some noise caused by momentary shock to the measuring instrument by a strong impact force after 0.0009 seconds, all time-strain graphs are continuous linear data, so the degree of impact force can be clearly identified.

It can be seen that panel specimen 1 hardly transmits the impact force during the delay time, effectively suppresses the tensile wave transmitted to the rear surface after the delay time, and reduces the strain caused by the compression wave to 4,000 με (microstrain) or less.

On the other hand, it can be seen that the impact force of panel specimen 2 is transmitted in a small but constant amount even during the delay time, and it can be confirmed that the strain due to the compression and tensile waves increases significantly compared to panel specimen 1 after the delay time. When compared with the maximum impact amount, it is confirmed that panel test specimen 2 delivered about 2.5 times the impact amount compared to panel specimen 1.

Therefore, it is confirmed that panel test specimen 1 has significantly less strength of compression and tensile waves due to contact explosion than panel specimen 2. In particular, it can be seen that the panel test specimen 1 has excellent suppression ability against tensile waves that cause serious destruction on the rear surface of the structure.

Through the above test results, the strength of the protection panel has little effect on the improvement of the protection performance, and when the main member that suppresses the explosive force in the protection panel does not come into direct contact with the wall (W), the front penetration as well as the rear destruction is effectively found to be suppressed.

[Reference Figure 7]

(a) and (b) of [Reference Figure 7] above are schematic diagrams showing the process of transmitting the impact force applied to the panel test body 1 and panel test body 2, respectively.

As shown in (a) of [Reference Figure 7], when an impact force is applied to the front surface of the panel test specimen 1, the impact absorbing material 10 located inside reinforces the toughness of the high-toughness panel 20 to reduce the impact force. Since the impact force is effectively reduced, and the impact force is dissipated through the impact absorbing material 10 in a state in which the impact force is reduced, and finally the impact force reaches the steel plate in a state where the impact force is reduced and lost, the impact force can be effectively reduced.

On the other hand, in the panel test specimen 2 shown in FIG. (b) of [Reference Figure 7], the impact force was weakened to a certain level by the impact absorbing material 10 disposed on the front side, but the weakened impact force was intact. ), and the impact force of the high-toughness panel 20 reaches the steel plate, and the impact force reduction effect is lowered compared to the panel specimen 1.

Therefore, through the above experiment, the impact absorbing material 10 is placed in close contact with the wall (W), and the high-toughness panel 20 is disposed on the front surface of the impact absorbing material 10, so that the wall (W), the impact absorbing material 10 ), it is confirmed that the explosion-proof performance is excellent when the high-toughness panel 20 is arranged from the inside to the outside in order.

2. Explosion-proof performance test of composite panel (1) for structure explosion-proof reinforcement

The experimental method for the explosion-proof performance of the composite panel 1 for explosion-proof reinforcement of a structure according to the present invention was carried out as an impact test using the impact resistance performance evaluation device of [Reference Figure 2], and the embodiment was carried out on the inside of the wall (W) as a standard. An explosion-proof reinforcing composite panel (1) was used, in which the impact absorbing material (10), the reinforcing sheet (30), and the high toughness panel (20) were arranged in order from the outer direction.

In the embodiment, the shock absorbing material (10) portion of the composite panel is formed with a thickness of 30 mm for the impact absorbing material 10, 5 mm for the reinforcing sheet 30, and 50 mm for the high toughness panel 20 so that the total thickness is 85 mm. The test was conducted by arranging it to be in close contact with the wall (W).

In Comparative Example 1, the test was conducted by adhering the panel having a thickness of 85 mm to the wall (W) by mixing at the same mixing ratio as the high-toughness panel (20) applied in the above example.

Type W
(kg) Unit weight (kg) Fiber (kg) actual volume
(L/m ³ ) cement fly
ash silica fume silica sand silica
powder blast furnace
slag polyamide fiber high intensity 400 270 65 - 135 - - 22.8 870 ultra high strength 250 769 - 77 846 231 154 22.8 996

(Table 1: cement composite formulation table, based on 1000L)

The mixing ratio of the cement composite applied to the high-toughness panel 20 of Examples and Comparative Examples was the high-strength type shown in [Table 1]. Through existing tests, it is desirable to apply a high-strength type with increased toughness because the increase in strength of the high-toughness panel 20 has little influence on the protective effect, in terms of economic feasibility and protection performance. Concrete with an elastic modulus of 24 Gpa and a tensile strength of 2.013 MPa was applied. It was set to 1,000 mm in width and 85 mm in thickness, and the fiber mixing ratio was set to 2.0 vol% to show strain hardening ability of 2.0% or more.

The reinforcing sheet 30 is a polypropylene sheet mixed with glass fibers, and the shock absorbing material 10 is formed of expanded polypropylene.

[Reference Figure 8] below is a time-strain graph of an embodiment, and [Reference Figure 9] is a time-strain graph of a comparative example.

[Reference Figure 8]

[Reference Figure 9]

In the embodiment, as shown in [Reference Figure 8], it can be seen that the shock wave arrives delayed from the initial collision point, and as the reinforcing sheet 30 is added, the generation of noise is suppressed compared to [Reference Figure 5] , it can be seen that the impact forces of compression and tension waves are lowered. In particular, it can be confirmed that the impact force decreases as the distance from the impact point increases when the measuring gauge is installed as a reference, so it can be confirmed that the transmission of the impact force is suppressed by controlling the shock wave in the embodiment.

In the comparative example, as shown in [Reference Figure 9], it can be seen that the shock wave arrives without delay and noise continuously occurs. In particular, when compared with the maximum impact amount, it is confirmed that the comparative example transmits about 2.5 times the impact amount compared to the embodiment. In addition, in the Comparative Example, although the impact force decreases as the distance from the impact point increases based on the installation surface of the measuring gauge, it is confirmed that a significant amount of impact force is transmitted to the peripheral area based on the impact amount at the impact point, and the dissipation of the impact force It can be seen that the protection performance is significantly lower than that of the embodiment in terms of control of the shock wave.

In addition, in addition to the above-described Example and Comparative Example 1, a comparative test was conducted on the actual destructive properties according to the difference in thickness.

When the explosion-proof panel is additionally installed on the existing building, it is difficult to fully express the performance of the explosion-proof panel if the explosion-proof panel is destroyed by the force of the explosion. Therefore, a test to compare the impact force absorption ability of the explosion-proof panel by observing the fracture properties of the specimen by classifying it by thickness was conducted as follows.

In the comparative example, the high-toughness panel 20 is applied to an explosion-proof panel manufactured with a thickness of 85 mm (Comparative Example 1), 50 mm (Comparative Example 2), and 200 mm (Comparative Example 3), respectively. A composite panel formed with a thickness of 30 mm for the cushioning material (10), 5 mm for the reinforcing sheet (30), and 50 mm for the high-toughness panel (20) was applied so that the overall thickness was 85 mm.

In each of the comparative examples and examples, the flying body of Figure 2 was directly collided with the same impact amount (340 m / s), and after the collision, the state of surface penetration and back separation was observed and compared with the naked eye.

[Reference Figure 10] below shows the results of the above crash test.

[Reference Figure 10]

Comparing Comparative Examples 1 to 3, it can be seen that as the thickness of the explosion-proof panel increases, the occurrence of surface penetration and back peeling is suppressed. Comparative Example 2 with a thickness of 50 mm is expected to significantly deteriorate the protection performance due to the most surface penetration and back peeling and significant area loss. In the case of Comparative Example 1 having the same thickness as the Example, it is expected that surface penetration and back peeling occur and area loss progresses, resulting in deterioration in explosion-proof performance. In the case of Comparative Example 3 having a thickness of 200 mm, only surface penetration occurs and peeling is hardly observed, but cracks on the surface are significantly generated, which may reduce the ability to delay the transmission of impact force. In the case of the examples, surface penetration occurred, but penetration occurred concentrated only at the impact portion, and it was confirmed that cracks and back peeling did not occur in the periphery. .

In particular, it is observed that the destruction ratio of the explosion-proof panel is lower in Example compared to Comparative Example 3 formed with a thickness of more than twice, and it is confirmed that higher explosion-proof performance can be expressed with a small thickness.

In addition, when the explosion-proof reinforcement composite panel 1 of the present invention is partitioned and installed according to a certain size on the wall (W), each panel can be standardized and manufactured as a module.

The explosion-proof reinforcement composite panel 1 can be constructed on the wall (W) by any method that can be combined with the wall (W), such as dry or wet.

In particular, when combined by a dry method, two or more through holes 40 are formed at the edge of the composite panel, and the head of the connecting material 2 embedded in the wall W penetrates through the through holes 40. Protruding forward of the composite panel and fastening the fixture 3 to the head of the connecting member 2 can further improve the speed of construction and explosion-proof performance.

[Figure 4a] to [Figure 4b] shows the construction process of the structure explosion-proof reinforcement composite panel (1) installation structure according to the present invention.

As shown in [Fig. 4a], it is preferable that the connecting member 2 embedded in the wall W is made of a buried bolt having a screw thread formed on the head.

In addition, in order for the explosion-proof reinforcement composite panel 1 to be stably mounted on the wall W, two or more through holes 40 are formed at the edge of the composite panel, and the connecting material 2 penetrates through the through holes 40. ) The head of the composite panel protrudes forward, and a fastener (3) such as a nut is fastened to the head of the connector (2) to stably fix the explosion-proof composite panel (1) to the wall (W). can

The installation structure of the explosion-proof reinforcement composite panel (1) can be quickly constructed by a dry method, and the entire portion of the explosion-proof reinforcement composite panel (1) is not coupled to the wall (W) but is fastened to the fixture (3). Only combined can attenuate the transmission of the shock wave from the explosion-proof reinforcing composite panel 1 to the wall W, thereby further improving the explosion-proof performance.

In addition, since only a portion of the high-toughness panel 20 is fixed to the wall, when an impact force is transmitted, the portion excluding the fixed end moves due to vibration when the impact force is transmitted, so that the shock can be dissipated without directly transferring it to the wall. At this time, the shock absorbing material 10 having excellent impact absorbing power is disposed adjacent to the inner side of the high toughness panel 20 to absorb the energy caused by the flow when the high toughness panel 20 flows, thereby dissipating the impact force of the high toughness panel 20. performance can be enhanced.

More specifically, the high-toughness panel 20 is disposed spaced apart from the wall surface W in a state in which both ends are coupled to the connecting member 2 . When an impact force is applied to the high toughness panel 20, the high toughness panel 20 to which the impact force is applied flows and vibrates while transmitting the impact force to the periphery of the portion to which the impact force is applied. As the shock wave moves to the periphery of the impact point, the high-toughness panel 20 moves forward and backward in the moving direction of the shock wave, and the impact energy is gradually lost.

In addition, the impact force applied to the central portion of the high toughness panel 20 is reduced while being converted into vibration energy by the flow of the high toughness panel 20, and the impact energy is transmitted along the high toughness panel 20 to form the high toughness panel 20. When reaching the connection point between the wall (W) and the connector (2) located in the periphery, the impact energy is reduced and finally the impact force transmitted to the wall (W) is effectively reduced.

A summary of the foregoing is as follows.

1) The explosion-proof panel, which is arranged in order of the shock absorbing material 10 and the high toughness panel 20 from the inside to the outside with respect to the wall W, has excellent protection performance.

2) The reinforcing sheet 30 may be disposed on the front, rear, or both sides of the high-toughness panel 20, and in each case, a predetermined protection performance is satisfied.

3) The protective performance for the purpose of reducing impact force and penetrating fracture is determined to be the best in the test specimen composed of the impact absorbing material 10, the reinforcing sheet 30, and the high-toughness panel 20.

1: Composite panel for explosion-proof reinforcement
10: shock absorbing material 20: high toughness panel
30: reinforcement sheet 40: through hole
2: connecting material
3 : fixture
w: wall

Claims (6)

In the composite panel for structure explosion-proof reinforcement constructed on the front of the wall to reinforce the explosion-proof performance of the structure,
a shock absorber disposed in close contact with the wall and made of foamed synthetic resin; and
a high-toughness panel disposed on the front surface of the impact absorbing material and made of fiber-reinforced ultra-high-performance concrete (UHPC);
A composite panel for explosion-proof reinforcement of a structure composed of a.
In paragraph 1,
A composite panel for structure explosion-proof reinforcement, characterized in that it is configured to further include; a synthetic resin material reinforcing sheet disposed on at least one of the front or rear surface of the high-toughness panel.
In paragraph 2,
The reinforcement sheet is a structure explosion-proof reinforcement composite panel, characterized in that molded of glass fiber reinforced plastic (GFRP).
In paragraph 1,
The shock absorber is expanded polypropylene (EPP), expanded polyethylene (EPE), expanded polyurethane (EPU), expanded polyolefin (EPO), expanded polystyrene (EPS), expanded phenolic resin (EPF), expanded polyvinyl chloride (PVC) , Foamed urea resin (EUF), foamed silicone (ESI), foamed polyamide (EPI) and foamed melamine resin (EMF) composite panel for structural explosion-proof reinforcement, characterized in that consisting of any one or more.
In paragraph 4,
The impact absorbing material has a density of 60 to 100 kg/m ³ , tensile strength of 10 to 20 kgf/cm ³ , elongation of 10 to 30%, compressive stress at 10% compression 4 to 8 kgf/cm ³ , and compressive stress at 25% compression 5 ~10 kgf/cm ³ , Composite panel for structure explosion-proof reinforcement, characterized in that the compressive stress of 6 ~ 12 kgf / cm ³ at 50% compression.
As an installation structure of the composite panel for explosion-proof reinforcement of a structure according to any one of claims 1 to 5,
Two or more through holes are formed at the edge of the composite panel,
The head of the connecting member embedded in the wall penetrates the through hole and protrudes forward of the composite panel;
Composite panel installation structure, characterized in that constructed by fastening the fixture to the head of the connecting material.

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