JP6534173B2 - Below the girder noise prevention structure having the anti-drop performance of concrete pieces and manufacturing method of the structure - Google Patents

Description

  The present invention relates to an under-girder noise preventing structure that reduces or absorbs noise generated from a road or railway running parallel to a road above a viaduct on the lower surface of a concrete viaduct, and a method of manufacturing the same.

  It is believed that the noise generated from the road provided under the viaduct parallel to the road above the viaduct reflects on the underside of the viaduct and causes environmental damage to the surrounding area of the road. Therefore, measures have been taken to eliminate or reduce this reflected sound. Specifically, a plate having sound absorbing performance is suspended below the viaduct to absorb noise and not reflect sound or reduce reflected sound. (For example, the structure under the beam disclosed in Japanese Patent Application Laid-Open No. 2001-090030, Japanese Patent Application Laid-Open No. 2001-317011) A plate having sound absorbing performance is called "back surface sound absorbing plate", and its structure is erected on the side of the road. It is almost the same as the sound absorption panel being constructed.

JP, 2001-090030, A JP 2001-317011 A

  The back surface sound absorption board is suspended and installed by the rod fixed by post installation anchor etc. to the elevated bridge, and it is thought that the load bearing performance of the fixed part will deteriorate by the vibration of a bridge etc. Therefore, it is necessary to carry out the inspection of the fixed part regularly, but the space between the back surface sound absorption board and the lower surface of the concrete viaduct is so small that the concrete viaduct is too small for human to enter. It is a situation where it can not be confirmed by close visual inspection. Therefore, it is not possible to appropriately grasp the danger of the back surface sound absorbing plate from falling, and the performance regarding the third party influence degree is extremely low.

  The third-party impact is the degree of impact on injuries to equipment and people, as stated in the Concrete Standard Specification (edited and published by the Japan Institute of Civil Engineers). Undersides of concrete structures such as viaducts with cross structures need to be free from damage to third parties even if peeling of concrete pieces occurs due to corrosion of rebar Performance is required.

  Then, this invention can improve the performance regarding a third party influence degree, and an object of this invention is to provide the under-girder noise prevention structure which has the anti-drop performance of a concrete piece, and the manufacturing method of the structure.

The anti-girder noise preventing structure according to the present invention comprises a anti- falling layer having a punching strength of 1.5 kN or more and adhered to a concrete surface on the lower side of concrete viaduct via a first adhesive material; And a sound absorbing layer disposed on the lower side and having an average oblique incident sound absorption coefficient of 0.7 or more.

Further, in the method of manufacturing the noise reduction structure under the beam according to the present invention, the first adhesive is applied to the concrete surface on the lower side of the concrete viaduct, and the peeling resistance of 1.5 kN or more on the concrete surface is prevented The process of applying a layer, and the process of applying a sound absorbing layer having an average grazing incidence sound absorption coefficient of 0.7 or more below the anti-sagging layer.

  ADVANTAGE OF THE INVENTION According to this invention, the performance regarding a third party influence degree can be improved, and the under-girder noise prevention structure which has the anti-drop performance of a concrete piece, and the manufacturing method of the structure can be provided.

«Girder noise prevention structure»
One embodiment of the under-girder noise preventing structure according to the present invention will be described.

  The under-girder noise prevention structure of the present embodiment is provided on the lower surface of a concrete viaduct of a highway provided parallel to a general road.

  An anti-slip layer adhered via a first adhesive is disposed on the concrete surface below the concrete viaduct. As the first adhesive, a known adhesive such as an epoxy resin-based adhesive containing an epoxy resin as a main component can be used. The epoxy resin-based adhesive is preferably a two-component mixture type in order to cure at normal temperature. In the case where the concrete viaduct has a crack or the like having a width of less than 0.2 mm, it is preferable that the first adhesive penetrate the crack in order to reinforce the concrete. For example, the viscosity of the first adhesive can be 5 to 15 Pa · s, preferably 6 to 12 Pa · s. It is preferable that the 1st adhesive material is 2.0 Mpa or more in adhesive strength measured by "the NEXCO test method 4th edition structure-related test method test method 426".

The anti-slip layer is adhered to the concrete via with a first adhesive. The punching resistance of the anti-slip layer is 1.5 kN or more. The punching resistance of the anti-slip layer can be measured, for example, by JSCE-K 533. The antiglare layer preferably has a durable performance such as preventing the entry of deterioration factors that promote steel corrosion during the scheduled service period of the structure. Durability performance can be measured, for example, by chloride ion permeability, and chloride ion permeability measured according to “NEXCO test method 4th edition, structure relationship test method test method 425” is 0.005 g before and after loading. It is preferable that it is / m ² · day or less. A known fiber sheet can be used for such anti-slip layer, and as a material of the fiber sheet, for example, vinylon fiber and polypropylene fiber can be mentioned.

  A sound absorbing layer bonded via a second adhesive is disposed on the lower surface of the anti-slip layer. As the second adhesive, a known adhesive such as an epoxy resin-based adhesive containing an epoxy resin as a main component can be used. The epoxy resin-based adhesive is preferably a two-component mixture type in order to cure at normal temperature. As such an adhesive, the same one as the first adhesive can be used. In the present embodiment, the second adhesive has a high affinity to both the anti-falling layer and the sound absorbing layer, and has an ability to integrate the anti-falling layer and the sound absorbing layer during the scheduled service period of the structure.

  The sound absorbing layer has an average grazing incidence sound absorption coefficient of 0.7 or more, preferably 0.9 or more. The average grazing incidence sound absorption coefficient is, for example, the test and calculation described in "Development of Sound-Reducing Plate with Large Noise Reduction Effect Briefing Material of the FY 1995 Construction Technology Evaluation System Publicly-Owned Task of FY 1995" of Ministry of Construction Notification 1860 It can be calculated by a method. The sound absorbing layer is preferably a non-combustible material. Judgment of nonflammability can be judged by evaluation of the self-extinguishing performance based on JIS K6911, for example. The sound absorbing layer preferably has UV resistance. The ultraviolet resistance performance can be measured, for example, based on JIS K7350-2. As the sound absorbing layer, for example, Thinsulate sound absorbing and heat insulating material (trade name, manufactured by 3M) can be used. The sound absorbing layer should meet the standard values for the performance required for the sound absorbing layer (average grazing incidence sound absorption coefficient, self-extinguishing performance, anti-falling performance, and shock absorbing performance) after accelerated testing for a period equivalent to 30 years. Is preferred.

  The under-girder noise prevention structure of the present embodiment is preferably noncombustible. For example, FMVSS (Federal Motor Vehicle Safety Standard) no. Based on 302, it can be judged from the burning rate, the burning distance, the burning rate, etc. whether the passing criteria are satisfied.

  In the present embodiment, the under-the-girder noise prevention structure is formed to be in contact with the lower side of the elevated bridge, so that it can be easily confirmed by the inspector by close visual inspection. In addition, since the under-girder noise prevention structure is provided with the anti-slip layer, it is possible to prevent the concrete pieces from being removed. Furthermore, since the sound absorbing layer is provided, noise can also be prevented.

  In the present embodiment, the second adhesive and the sound absorbing layer are arranged in order below the anti-dip layer, but another functional layer may be provided between the anti-drop layer and the sound absorbing layer. For example, other sound absorbing layers. Due to the nature of the sound absorbing layer, it is preferable that the sound absorbing layer be disposed at the lowermost side as in the present embodiment.

«Method of manufacturing noise reduction structure under the girder»
Next, one of the embodiments of the method of manufacturing the underfloor noise prevention structure according to the present invention will be described.

  In order to form the below-girder noise prevention structure, first, the surface of the concrete below the concrete viaduct is roughened. In the roughening, integration of the roughened concrete and the first adhesive layer can be achieved. That is, the punching resistance of the anti-slip layer can be increased. By roughening, unevenness can be formed on the concrete surface.

  There is no limitation on the method of graining, and it can be carried out using a known apparatus such as water jet, steel shot blast, sand blast and the like.

When roughening is performed by water jet, although depending on the type of nozzle, for example, the water pressure can be 50 to 250 MPa. The water jet is preferably adjusted in water pressure, flow rate, number of passes, and density in accordance with the type of nozzle. Specifically, for example, in the case of a nozzle that rotates and oscillates, it is preferable to use a water pressure of 150 MPa, a flow rate of 5.2 L / min, a pass number of 1, and a density of 3.01 kwh / m ² . Moreover, if it is one rotating nozzle, the flow rate is 9.6 L / min, the number of paths is 2, the density is 1.52 kwh / m ² when the water pressure is 100 MPa, and the flow rate is 11.8 L / min, the number of paths is 1 when the water pressure is 150 MPa. And, when the density is 1.49 kwh / m ² and the water pressure is 200 MPa, the flow rate can be 13.6 L / min, the number of paths is 1, and the density can be 1.51 kwh / m ² . If it is four rotating nozzles, the water pressure can be 70 MPa and the flow rate can be 77.0 L / min.

When graining is performed by steel shot blasting, the projected density can be 100 to 200 kg / m ² .

When graining is performed by sandblasting, the jet density can be 10 to 50 kg / m ² .

  Before the roughening, about 1 mm of the surface of the concrete may be cleaned in order to remove the fragile layer, the reitance, the dust and the like present on the surface of the concrete.

  Once the roughening is complete, the first adhesive is subsequently applied to the roughened concrete surface. The application can be performed using a known method such as spray application.

  After applying the first adhesive, at least the surface to which the first adhesive is applied is coated with a anti-slip layer. The anti-slip layer can, for example, be adhered to the concrete surface manually.

  Next, a second adhesive is applied to the surface of the anti-slip layer. The application can be performed using a known method such as spray application.

  Finally, a sound absorbing layer is applied to the surface to which at least the second adhesive is applied. The sound absorbing layer can, for example, be adhered to the concrete surface manually.

Claims (5)

The anti- falling layer having a punching strength of 1.5 kN or more, which is adhered to the concrete surface on the lower side of the concrete via the first adhesive.
And an acoustic absorption layer having an average grazing incidence sound absorption coefficient of 0.7 or more, which is disposed below the anti-sagging layer.   The noise reduction structure under the girder according to claim 1, wherein the sound absorbing layer is adhered to the anti-slip layer via a second adhesive. Applying a first adhesive to the surface of the concrete under the concrete viaduct, and applying an anti- breakout layer having a punching resistance of 1.5 kN or more on the surface of the concrete;
And (b) applying a sound absorbing layer having an average grazing incidence sound absorption coefficient of 0.7 or more below the anti-slip layer.   The method for manufacturing the under-the-girder noise prevention structure according to claim 3, wherein a second adhesive is applied to the lower surface of the anti-slip layer, and the sound absorbing layer is adhered to the anti-slip layer. The method of manufacturing the under-girder noise prevention structure according to claim 3, further comprising the step of roughening the concrete surface under the concrete viaduct.