2. Monitoring of structures adjacent to geotechnical works Joanna Pieczynska, Jaroslaw Rybak Wroclaw University of Technology

3. Main ideas Sheet piling. –Piling technologies (driving, press-in method). Ground improvement –Technologies – impact on neighborhood. Case studies – examples of monitoring

4. Deep excavations Wroclaw – historical city-center

5. Traditional methods Pile driver Vibrator

6. Press – in method

7. Close, closer …

8. Deep excavation University of Wroclaw Faculty of Law

9. How to reduse the impact ? Pre-boring

10. How to reduse the impact ? jetting

11. How to reduse the impact ? jetting

12. Monitoring Type of property Peak particle velocity [mm/s] Continuous vibrationTransient vibrations Ruins, buildings of architectural merit24 Residential510 Light commercial1020 Heavy industrial1530 Buried services2540

13. Monitoring – Techniczna street Daily report – peak particle velocity

14. Monitoring – Techniczna street Daily report – peak particle velocity

15. Monitoring – Techniczna street At 12:33:15 on 5 February 2010 the sensor recorded an excitation increasing in the period of 15 seconds to the value of 200 mm/s, and in the subsequent 15 seconds – incremented by another 50 mm/s. The character of the value was not accidental, but rather illustrated a propagating seismic wave. Unfortunately, the sensor was set at the test range of 0 – 250mm/s and after exceeding this range, it turned off. It is obvious that after the above shown results are marked on the DIN4150 diagram, the effect will considerably differ from all possible safety levels. After the afore- mentioned situation had been recorded, tedious search took place in order to confirm that the seismic wave was truly excited in the neighborhood.

16. Monitoring – Techniczna street Finally, at about 3:00 p.m. the Bobrek – Bytom Centrum Mine provided information that there had been a crump which released a great amount of energy. The mine determined the excitation at the level of 2.7 degrees of the Richter scale. Unfortunately, the caution on the part of the investor did not prevent the neighboring houses from damages; it only saved the geotechnical company from paying damages, as the failure had not been caused by their work

17. Monitoring – examples Powązkowski National Cementary

18. Monitoring – examples Cementary wall

19. Monitoring of vibrations Cementary wall Graves

20. Peak particle velocities

21. Peak particle velocities / frequency

22. Monitoring – dynamic replacement Residential house near building site

23. Monitoring – daily report

24. Monitoring – bridge abutment New built bridge abutment. Problem of vibration impact on early concrete.

25. Monitoring – daily report

26. Monitoring – equipment Heavy noise control

27. Conclusion The analysis of vibrations of the background that permanently influences the monitored structures makes it possible to determine precisely the permissible frequency of vibrations and thus to take into account lower efficiency of works in calculating overall costs. Although the monitoring programs may be in practice diversified, complex and perfectly adjusted to even very demanding construction technologies, the difficulty lies in the assessment of the proportions between the real needs, the proper monitoring scope and the financial resources of the investor, who, in the end, pays for such investigation. It is however worth emphasizing that the costs of such examination are much lower than the potential damages that may be thus avoided.

28. Thank you for your attention