Report b Measurement report. Sylomer - field test

Transcription

1 Report b Meaurement report Sylomer - field tet

2 Report b 2(16) Contet 1 Introduction Cutomer The ite and purpoe of the meaurement Meaurement Attenuation of the noie level Attenuation on one third octave band Concluion...16

3 Report b 3(16) 1 Introduction 1.1 Cutomer Chritian Berner Oy / Getzner Werktoffe Tuoma Laitinen PL VANTAA 1.2 The ite and purpoe of the meaurement The ite i located in outhern Finland and the hortet ditance between the building and the railway track i about 40 meter. Before tarting the planning proce of the building, vibration meaurement were carried out at the ite. The etimated ground borne noie level L A,S,max (maximum A-weighted ound preure level during a train paing meaured uing time contant low) in the building wa about db. In order to attenuate ground borne noie level induced by the railway traffic a iolator ytem wa deigned and intalled in the building. The requirement for iolator ytem were derived from vibration meaurement reult by Helimaki Acoutic. The deigning of the ytem and the calculation for acoutical repone of the ytem were carried out together by Helimaki Acoutic, Chritian Berner and Getzner Werktoffe. The field meaurement of the Sylomer iolator were carried out at a contruction ite. At the time of meaurement the building wa almot finihed and the iolator had reached approximately at leat 90 % of the full loading. The purpoe of the meaurement wa to invetigate the real attenuation achieved in the field with the iolator. The meaured building had even floor. The horizontal Sylomer layer were 18mm thick and the vertical layer 6mm (figure 1 5). Figure 1. Building i upported by the concrete pile.

4 Report b 4(16) Figure 2. Below the horizontal Sylomer layer (blue) i an uniolated part of building foundation and on top of the iolator i the iolated part of building foundation. Figure 3. In different loading poition a different type of Sylomer wa ued. Different Sylomer type have different color.

5 Report b 5(16) Figure 4. The maintenance pace under the building. Figure 5. The ide of an iolated part of foundation that would be left under the ground level after finihing the building were covered with vertical layer of 6mm Sylomer that wa protected by an EPS layer.

6 Report b 6(16) 2 Meaurement Meaurement of the vibration level wa done with meaurement unit having eight ynchronized channel. Six of the channel were equipped with accelerometer in order to meaure the vibration level in three direction imultaneouly at two point. The upper meaurement point wa located at the iolated part of building foundation and the other meaurement point wa located underneath the Sylomer at uniolated part of building foundation. Vibration meaurement were done from two different poition (annex 1 & 2 and figure 6). One of the channel wa equipped with microphone in order to meaure the ound level in the reference room. Reference room wa located at the other ide of the building than the railroad. The aim wa to minimize the effect of the airborne noie. All meaurement were done with the vibration excitation induced by the train paing. Figure 6. Upper meaurement point i on the iolated and the econd meaurement point i on the uniolated part of building foundation. The horizontal Sylomer layer eparating the building part i underneath the vertical Sylomer layer. The blue line how the location of horizontal layer. 2.1 Attenuation of the noie level The meaured horizontal groundborne noie level at the uniolated part of foundation were db lower than the vertical level. In the earlier urvey that were done before the tart of the building proce, all direction were aumed to be critical. Epecially low frequency (<12Hz) vibration level in horizontal direction were coniderable. The reaon for horizontal vibration level being now coniderably lower than in planning

7 Report b 7(16) tage i aumed to be becaue of the different kind of tranfer function for the vertical and horizontal vibration between the ground and foundation. Becaue the vertical vibration level wa coniderably higher than the horizontal direction, it i quite afe to aume that the meaured noie level at the reference room were caued by the vertical component of the vibration. The meaured attenuation value for the Sylomer iolator are hown in the table 1. Attenuation i defined uing two different method. In the firt column the attenuation i defined uing the difference between the meaured noie level at the reference room and the calculated ground borne noie level meaured from the uniolated part of the building foundation. Calculation of the ground borne noie level from the meaured vibration ignal i done according to the recommendation given by VTT (Technical Reearch Centre of Finland). Calculation method ue reference velocity of 1 nm/ and i baed on calculation model publihed by Federal Tranit Adminitration of U.S.A. ( and When a tarting value for calculation i the meaured velocity level from building foundation the calculation model taken into account following parameter: reonance, A-weighting, converion from inch/ to m/, afety margin, floor in which the analyi i made. In the econd column the attenuation i defined uing the difference between the calculated ground borne noie level from the meaured vibration ignal of the iolated and uniolated part of the foundation. The poition number in the table correpond to iolator numbering in the iolator plan done in the planning tage. Table 1. The meaured average attenuation in different direction. Poition Direction Attenuation between Attenuation between reference room and iolated and uniolated uniolated foundation part of founda- [db] 1) tion [db] 2) vertical Poition 12 perpendicular to track - 3) 7 4) along the track - 3) - 5) vertical 12 6 Poition 26 perpendicular to track - 3) 6 4) along the track - 3) - 5) 1) compare to figure ) compare to figure ) Noie level in the reference room i caued by the vertical vibration component and therefore the attenuation in horizontal direction i impoible to define uing the meaured noie level. 4) Attenuation wa not poible to define from ome of the train paing becaue the meaured vibration level from the iolated part of foundation were too cloe to background level. 5) Attenuation wa not poible to define becaue the meaured vibration level from the iolated part of foundation were equal to background level. Theoretically the comparion between the uniolated and iolated part of foundation hould give more accurate reult about the achieved attenuation level for the iolator. In thi cae the relatively high background vibration level in the building made it impoible to meaure the real vibration level induced by the train. The background vibration level in the building were caued by the HWAC equipment. Therefore the attenuation defined uing the meaured noie level in reference room and calculated ground borne noie level in uniolated part of foundation i more reliable. Becaue the vertical vibration level in uniolated foundation were dominant compared to horizontal component, the attenuation wa poible to define only in vertical direction. A train paing meaured in vertical direction from the uniolated foundation from poi-

8 Report b 8(16) tion 12 i hown in figure 7. Ground borne noie level for the ame paing are hown in figure 8. Taking into account 2dB attenuation/floor aumed in the VTT recommendation, one can define difference between the maximum noie level in the room and in the vertical direction in uniolated foundation to be 18 db. From the figure 8 one can alo eaily ee that the vertical component i dominant. The correponding reult from poition 26 are hown in figure 9 and 10. The vertical component i again dominant. Comparing the maximum noie level in the reference room to the vertical ground borne noie level in uniolated part of foundation, difference of 10 db can be defined. mm/^ Figure 7. Linear acceleration ignal of a train paing meaured from poition 12 in vertical direction (uniolated foundation).

9 Report b 9(16) db(a) Figure 8. Ground borne noie level of a train paing are hown in figure 7. From top to bottom: uniolated foundation vertical direction, uniolated foundation along the track, uniolated foundation perpendicular to track and meaured noie level in reference room. mm/^ Figure 9. Linear acceleration ignal of a train meaured from poition 26 in vertical direction (uniolated foundation).

10 Report b 10(16) db(a) Figure 10. Ground borne noie level of the train paing are hown in figure 9. From top to bottom: uniolated foundation vertical direction, meaured noie level in reference room, uniolated foundation along the track and uniolated foundation perpendicular to track. In the figure the attenuation a a function of time during a train paing are hown. According to figure 12 one can ee that in poition 12 the maximum attenuation in vertical direction i 12 db and the average attenuation i 10 db. For the poition 26 the correponding value are 7 db and 6 db during a train paing. The background vibration level in the building diturbed the analyi of the attenuation value epecially on the higher frequency band (ee the next chapter). Therefore the attenuation could be even higher than tated above. In the figure 13 the correponding attenuation value are hown when the calculation i done in the direction perpendicular to track. According to figure 13 on can ee that in poition 12 the maximum attenuation perpendicular to track i 9 db and the average attenuation i 6 db. For the poition 26 the correponding value are 8 db and 6 db during a train paing. Attenuation wa not poible to define from ome of the train paing becaue the meaured vibration level from the iolated part of foundation were too cloe to background level. In the figure 14 the correponding attenuation value are hown when the calculation i done in the direction along the track. Attenuation wa not poible to define becaue the meaured vibration level from the iolated part of foundation were equal to background level. A mentioned earlier the horizontal vibration level in the uniolated part of foundation were notably lower than the vertical vibration level and therefore only the vertical component wa relevant. The meaured ground borne noie level in the building fulfilled the requirement et in the planning phae (L A,S,max 30). In the figure 15 meaured A-weighted ound preure level on one third octave band during a train paing in the reference room are hown.

11 Report b 11(16) mm/^ mm/^ Figure 11. On the left a meaured train paing from poition 12 i hown and on the right from the poition db(a) 15.0 db(a) Figure 12. Attenuation between the uniolated part of foundation and iolated part of foundation in vertical direction during train paing. Reult are derived from the ignal hown in figure

12 Report b 12(16) db(a) 15.0 db(a) Figure 13. Attenuation between the uniolated part of foundation and iolated part of foundation meaured perpendicular to track during train paing. Reult are derived from the ignal hown in figure 11. db(a) 15.0 db(a) Figure 14. Attenuation between the uniolated part of foundation and iolated part of foundation meaured along the track during train paing. Attenuation are derived from the ignal hown in figure 11.

13 Report b 13(16) Figure 15. Meaured A-weighted ound preure level in the reference room during a train paing on one third octave band. 2.2 Attenuation on one third octave band The attenuation on one third octave band wa defined by comparing the vibration level between the uniolated and iolated part of building foundation. In figure 15 the calculated attenuation value in vertical direction are hown. The HWAC intallation/equipment caued relatively high background vibration level in the building and therefore the attenuation value could not be defined on the frequencie over 80 Hz. If the vibration level caued by the HWAC-equipment effect on the reult below 80 Hz, the real attenuation value are higher than hown in figure 16. In figure 17 and 18 the correponding attenuation value are hown in horizontal direction. In the direction perpendicular to track attenuation value were poible to define only up to 63 Hz. On higher frequencie vibration level were not poible to eparate reliably from the background level. In the direction along the track the value are unreliable through the frequency band.

14 Report b 14(16) Figure 16. Attenuation value defined in vertical direction on one third octave band between the uniolated and iolated part of building foundation. The HWAC intallation/equipment caued the high background vibration level in the building and therefore calculation of attenuation value on the frequencie above 80 Hz wa not poible. Figure 17. Attenuation value defined in the direction perpendicular to track on one third octave band between the uniolated and iolated part of building foundation. Above 63 Hz the meaured vibration level were o low that the calculation wa not poible.

15 Report b 15(16) Figure 18. Attenuation value defined along the track on one third octave band between the uniolated and iolated part of building foundation. The meaured vibration level in thi direction were o low that the reult are not reliable through the frequency band.

16 Report b 16(16) 3 Concluion The meaured ground borne noie level in reference room induced by train fulfilled the requirement et in the planning phae L A,S,max 30dB. Meaured vibration level from the uniolated part of building foundation revealed that the vertical component wa dominant. In fact the horizontal vibration level were o cloe to the background level that it caued problem when the attenuation value were defined in horizontal direction. All the meaurement were carried out uing real train paing a an excitation ignal. Therefore better and more reliable reult epecially on higher frequencie and in horizontal direction might have been achieved, if the man-made excitation would have been ued. However from the noie level meaurement of the train paing it wa poible to define that the noie level in the building fulfilled the requirement et in the planning phae. Becaue the vertical component wa clearly dominant, it wa poible to define the attenuation value in vertical direction by comparing the meaured noie level in reference room and the calculated ground borne noie level in uniolated part of foundation. Uing thi method an average attenuation of 17 db wa achieved in poition 12 and 12 db in poition 26. Variation in reult from different poition i not due to different Sylomer type in different poition. Thi i becaue the whole iolated tructure form an integrated ytem. In thi cae the comparion between meaured noie level in reference room and calculated groundborne noie level in uniolated part of building foundation correpond better to the achieved total attenuation with the iolator becaue the comparion between uniolated and iolated part of foundation wa interfered by the vibration caued by the HWAC equipment inide the building. According to the meaurement achieved attenuation level with the iolation ytem fulfill the etimation and requirement defined in the planning tage. In order to achieve better iolation a thicker layer of Sylomer hould be ued. Reult reveal that it i poible to etimate the iolation efficiency with reaonable accuracy in the planning phae if the vibration level are meaured in advance at the ite and if the material propertie are well documented. Rauma Timo Huhtala Heikki Helimäki M. Sc. M. Sc. Helimaki Acoutic Rauma Helimaki Acoutic - Helinki Lyeokatu 5A3 Temppelikatu 6B Rauma, Finland Helinki, Finland timo.huhtala@helimaki.fi heikki.helimaki@helimaki.fi

17 INSINÖÖRITOIMISTO HEIKKI HELIMÄKI OY Temppelikatu 6 B, Helinki Puh , fax S-poti info@helimaki.fi b Sylomer - field tet Meaurement point Annex 1 Vibration meaurement were done from two different poition: poition 12 (Sylomer type I) and poition 26 (Sylomer type II). In both poition the upper vibration meaurement point wa located at the iolated part of building foundation and the other meaurement point wa located underneath the Sylomer at uniolated part of building foundation. In all meaurement point the vibration wa meaured in all three direction. Noie level were meaured in the reference room with microphone.

18 INSINÖÖRITOIMISTO HEIKKI HELIMÄKI OY Temppelikatu 6 B, Helinki Puh , fax S-poti info@helimaki.fi b Sylomer - field tet Meaurement point Annex 2 Meaurement point marked in the building foundation plan. Poition number correpond to iolator numbering in the calculation done in the planning tage of the building ASUINRAKENNUKSESTA gk=146 kn/m qk= 8 kn/m gk=376 kn/m qk= 95 kn/m gk=371 kn/m qk= 70 kn/m gk=470 kn/m qk=101 kn/m gk=496 kn/m qk=114 kn/m gk=258 kn/m qk= 58 kn/m gk=247 kn/m qk= 47 kn/m gk=166 kn/m qk= 20 kn/m gk=247 kn/m qk= 47 kn/m 24 gk=339 kn/m qk= 66 kn/m gk=166 kn/m qk= 20 kn/m gk=320 kn/m qk= 65 kn/m gk=118 kn/m qk= 8 kn/m gk=180 kn/m qk= 69 kn/m gk=118 kn/m qk= 8 kn/m gk=389 kn/m qk= 92 kn/m gk=412 kn/m qk= 68 kn/m gk=263 kn/m qk= 34 kn/m 1700 gk=345 kn/m qk= 56 kn/m 1600 gk=86 kn/m qk=55 kn/m 400 gk=152 kn/m qk= 75 kn/m gk=337 kn/m qk= 56 kn/m gk=93 kn/m gk=458 kn/m qk=161 kn/m gk=383 kn/m qk= 59 kn/m gk=93 kn/m gk=93 kn/m gk=152 kn/m qk= 75 kn/m