Vittorio Giavotto, Professor Emeritus, Polytechnic University of Milan and Convenor of TG1 Bridge parapets containment level – will they handle impacts by Tourist (or inter- urban) Coaches? (Engelsk) Virtual tests demonstrate that impacts of present-day tourist coaches require bridge parapets of containment categories H3 or H4. The old category with a full scale test with a 13 ton bus, is no more adequate for this purpose.

1. BRIDGE PARAPETS CONTAINMENT LEVEL
will they handle impacts by coaches?
Vittorio Giavotto
Convenor of CEN/TC226/WG1/TG1
Oslo – February 6-7, 2020Der nasjonale Vegsikringskonferansen

2. When a coach falls off a bridge
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

3. When a coach falls off a bridge
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• In general there are no survivors, as in airplane
accidents

4. When a coach falls off a bridge
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• In general there are no survivors, as in airplane
accidents
• Bridge parapets should prevent such accidents

5. The containment Level H2
• In EN1317 the containment Level H2 was
established in 1990, for parapets capable of
restraining coaches on bridges
Der nasjonale
Vegsikringskonferansen
Oslo – February 6-7, 2020

6. The containment Level H2
• In EN1317 the containment Level H2 was
established in 1990, for parapets capable of
restraining coaches on bridges
• For the Level H2 the containment test is the impact
of a bus with a mass of 13000 kg, at 70 km/h and
20°
Der nasjonale
Vegsikringskonferansen
Oslo – February 6-7, 2020

7. The containment Level H2
• In EN1317 the containment Level H2 was
established in 1990, for parapets capable of
restraining coaches on bridges
• For Level H2 the containment test is the impact of a
bus with a mass of 13000 kg, at 70 km/h and 20°
• Since then, the coaches evolved, becoming heavier,
taller and faster, more and more different from urban
buses
Der nasjonale
Vegsikringskonferansen
Oslo – February 6-7, 2020

8. The containment Level H2
• In EN1317 the containment Level H2 was
established in 1990, for parapets capable of
restraining coaches on bridges
• For Level H2 the containment test is the impact of a
bus with a mass of 13000 kg, at 70 km/h and 20°
• Since then, the coaches evolved, becoming heavier,
taller and faster, more and more different from urban
buses
• As a result, barriers CE marked in Level H2 cannot
contain today’s tourist coaches on highway bridges
Der nasjonale
Vegsikringskonferansen
Oslo – February 6-7, 2020

9. Current coaches
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• Current tourist coaches
have mass from 18000 to
24000 kg, and even more

10. Current tourist coaches
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• Current tourist coaches
have mass from 18000 to
24000 kg, and even more
• On highways coaches travel
at the limit speed, 90 or
100 km/h, in most European
Countries

11. Current tourist coaches
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• Current tourist coaches
have mass from 18000 to
24000 kg, and even more
• On highways coaches travel
at the limit speed, 90 or
100 km/h, in most European
Countries
• Urban buses have smaller
mass and lower platform,
that helps considerably in
tests on low barriers

12. Current tourist coaches
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• Current tourist coaches
have mass from 18000 to
24000 kg, and even more
• On highways coaches travel
at the limit speed, 90 or
100 km/h, in most European
Countries
• Urban buses have smaller
mass and lower platform,
that helps considerably in
tests on low barriers
• The tests on H2 barriers are
still performed with urban
buses

13. Impact energy
• The simplest parameter to evaluate the intensity of
an impact on a safety barrier is the kinetic energy of
the impacting vehicle, relative to the lateral
component of its velocity:
𝑇 =
1
2
𝑀 𝑉 sin 𝜃 2
[𝑘𝐽]
• Where:
– M [tons] is the mass of the vehicle
– V [m/s] the impact velocity
– 𝜃 the impact angle
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

14. Impact energy
• The simplest parameter to evaluate the intensity of
an impact on a safety barrier is the kinetic energy of
the impacting vehicle, relative to the lateral
component of its velocity:
𝑇 =
1
2
𝑀 𝑉 sin 𝜃 2 [𝑘𝐽]
• Where:
– M [tons] is the mass of the vehicle
– V [m/s] the impact velocity
– 𝜃 the impact angle
• Impact energy is not enough: impacts with the same
energy but different vehicle, mass, velocity and
angle may give different results
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

15. Impacts by coaches
• The impact used to assess the containment of a
parapet in its Level should be a significant worst
case
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

16. Impacts by coaches
• The impact used to assess the containment of a
parapet in its Level should be a significant worst
case
• Statistical studies from US show that the speed at
the impact on a barrier is about 20 km/h less than
the travel speed
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

17. Impacts by coaches
• The impact used to assess the containment of a
parapet in its Level should be a significant worst
case
• Statistical studies from US show that the speed at
the impact on a barrier is about 20 km/h less than
the travel speed
• Then, the significant worst case, for impacts of
coaches on highway barriers, can be a mass of 24t
and a speed of 70-80 km/h (depending on the speed
limit in force)
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

18. Impacts by coaches
• The impact used to assess the containment of a
parapet in its Level should be a significant worst
case
• Statistical studies from US show that the speed at
the impact on a barrier is about 20 km/h less than
the travel speed
• Then, the significant worst case, for impacts of
coaches on highway barriers, can be a mass of 24t
and a speed of 70-80 km/h (depending on the speed
limit)
• Accordingly the impact angle can be the usual 20°
for 70 km/h, and something less for 80 km/h
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

19. Impact energies of tourist coaches
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

20. Compatibility with EN 1317 Levels
• The impact energies of the 24t and of the 18t
coaches are not compatible with the containment
Level H2
• The impact energy of the 24t coach at 80 km/h-16°
and the one of the 18t coach at 80 km/h-20° are
compatible with the containment Level H3
• The impact energy of the 24t coach at 80 km/h and
20° is compatible with the containment Level H4b
• Possibly even the 24 coach at 70km/h-20° can be
contained by Level H3 parapets
• The impact energy is just a rough criterion – more
reliable evaluations can be done by Virtual Testing
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

21. Verification by virtual tests
• The word Virtual Test means Dynamic Analysis of
an impact test, made with Finite Elements or Multi
Body procedures
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

22. Verification by virtual tests
• The word Virtual Test means Dynamic Analysis of
an impact test, made with Finite Elements or Multi
Body procedures
• Virtual Tests cannot replace full scale Physical Tests
in the assessment of safety barriers, but they can be
used e.g. to assess barrier modifications
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

23. Verification by virtual tests
• The word Virtual Test means Dynamic Analysis of
an impact test, made with Finite Elements or Multi
Body procedures
• Virtual Tests cannot replace full scale Physical Tests
in the assessment of safety barriers, but they can be
used e.g. to assess barrier modifications
• To be accepted Virtual Tests must use Validated
Models, i.e. models confirmed by comparison with
physical tests.
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

24. Verification by virtual tests
• The word Virtual Test means Dynamic Analysis of
an impact test, made with Finite Elements or Multi
Body procedures
• Virtual Tests cannot replace full scale Physical Tests
in the assessment of safety barriers, but they can be
used e.g. to assess barrier modifications
• To be accepted Virtual Tests must use Validated
Models, i.e. models confirmed by comparison with
physical tests.
• The Virtual Tests and in particular the Validation
must be done according to prEN16303
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

25. H2 barrier-TB51, Coach 13t, 70 km/h, 20°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

26. Virtual test: H2 barrier, Coach 24t, 70 km/h, 20°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

27. Virtual Tests on Level H3 barriers
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• 6 H3 barriers were tested, 1 median and 5 parapets
• 5 in steel and 1 in concrete, all with validated models

28. Virtual Tests on Level H3 barriers
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• 6 H3 barriers were tested, 1 median and 5 parapets, 5 in
steel and 1 in concrete, all with validated models
• Virtual test were done on the 6 barriers, with the 24 t
coach at 70 km/h-20° and 80 km/h-16°

29. Virtual Tests on Level H3 barriers
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020
• 6 H3 barriers were tested, 1 median and 5 parapets, 5 in
steel and 1 in concrete, all with validated models
• Virtual test were done on the 6 barriers, with the 24 t
coach at 70 km/h-20° and 80 km/h-16°
• The impact of the 18 t bus at 80 km/h-20° was also
analyzed

30. H3 barrier n.1, Coach 24t, 70 km/h, 20°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

31. H3 barrier n.1, Coach 24t, 80 km/h, 16°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

32. H3 barrier n.2, Coach 24t, 70 km/h, 20°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

33. H3 barrier n.2, Coach 24t, 80 km/h, 16°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

34. H3 barrier n.3, Coach 24t, 70 km/h, 20°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

35. H3 barrier n.3, Coach 24t, 80 km/h, 16°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

36. H3 barrier n.4, Coach 24t, 70 km/h, 20°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

37. H3 barrier n.4, Coach 24t, 80 km/h, 16°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

38. H3 barrier n.5, Coach 24t, 70 km/h, 20°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

39. H3 barrier n.5, Coach 24t, 80 km/h, 16°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

40. H3 barrier n.6, Coach 24t, 70 km/h, 20°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

41. H3 barrier n.4, Coach 24t, 80 km/h, 16°
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

42. H3 barrier n. 1
TB61
Coach 18t 80km/h, 20°
Coach 24t 80km/h, 16°
Oslo – February 6-7, 2020Der nasjonale Vegsikringskonferansen
Coach 24t 70km/h, 20°

43. H3 barrier n. 2
TB61
Coach 18t, 80km/h, 20°
Oslo – February 6-7, 2020
Der nasjonale
Vegsikringskonferansen
Coach 24t, 70km/h, 20°
Coach 24t, 80 km/h, 16°

44. H3 barrier n. 3
Oslo – February 6-7, 2020
Der nasjonale
Vegsikringskonferansen
TB61
Coach 24t, 70km/h, 20°
Coach 18t, 80km/h, 20°
Coach 24t, 80km/h, 16°

45. H3 barrier n. 4
Oslo – February 6-7, 2020
Der nasjonale
Vegsikringskonferansen
TB61
Coach 18t, 80km/h, 20°
Coach 24t, 70km/h, 20°
Coach 24t, 80km/h, 16°

46. H3 barrier n. 5
Der nasjonale
Vegsikringskonferansen
Oslo – February 6-7, 2020
TB61
Coach 18t, 80km/h, 20°
Coach 24t, 70km/h, 20°
Coach 24t, 80km/h, 16°

47. H3 barrier n. 6
Der nasjonale
Vegsikringskonferansen
Oslo – February 6-7, 2020
TB61
Coach 18t, 80km/h, 20°
Coach 24t, 70km/h, 20°
Coach 24t, 80km/h, 16°

48. Performance of H3 barriers with 18t coach
Der nasjonale
Vegsikringskonferansen
Oslo – February 6-7, 2020
Barrier
n.
TB61
Coach 18 t
80km/h, 20°
Coach 24 t
70km/h, 20°
Coach 24t
80km/h, 16°
1 2.59 2.82 2.25 1.75
2 1.16 1.18 1.02 0.99
3 1.63 1.81 1.68 1.60
4 1.49 1.74 1.16 1.16
5 0.70 0.92 0.63 0.59
6 1.18 1.86 1.33 0.81
Working Width [m]
• Virtual tests confirmed the containment of coaches by H3 barriers
• However the working widths with similar energies are different

49. Conclusions
• Current H2 Level cannot contain extra-urban
coaches
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

50. Conclusions
• Current H2 Level cannot contain extra-urban
coaches
• The impact of the typical heavy coaches with a
mass of 24000kg at 70 km/h 20°, or 80 km/h 16°,
can be easily contained by current H3 barriers
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

51. Conclusions
• Current H2 Level cannot contain extra-urban
coaches
• The impact of the typical heavy coaches with a
mass of 24000kg at 70 km/h 20°, or 80 km/h 16°,
can be easily contained by current H3 barriers
• The containment of the same coaches at 80 km/h
and 20° requires H4b barriers
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020

52. Conclusions
• Current H2 Level cannot contain extra-urban
coaches
• The impact of the typical heavy coaches with a
mass of 24000kg at 70 km/h 20°, or 80 km/h 16°,
can be easily contained by current H3 barriers
• The containment of the same coaches at 80 km/h
and 20° requires H4b barriers
• To avoid false messages to the users, the vehicle
for the containment test of the current Level H2
should be changed from a bus to a truck of the
same mass
Der nasjonale Vegsikringskonferansen Oslo – February 6-7, 2020