Dynamic Interaction of Soil and Structure

Dynamic interaction between Soil, Monuments and Built Environment

International Workshop DISS_13 – Rome, December 12, 2013

Effects of ambient vibrations on heritage

buildings: overview and wireless dynamic

monitoring application

Giorgio Monti

Rossella Rea

Barbara Nazzaro

Fabio Fumagalli

Giuseppe Carlo Marano

Giuseppe Quaranta

Effects of vibrations on heritage buildings

• Ambient vibrations arising from man-made sources (e.g.

construction activities, vehicle and rail traffic) may interfere with

surrounding built environment.

• Special attention on heritage buildings subjected to ambient

vibrations

– Vibrations of small amplitude do not represent, in general, an impellent

hazard but they can increase (over the years) the structural vulnerability

in damaged and/or deteriorated elements of heritage buildings.

• Assessment

– Numerical methods

– Experimental methods

Dynamic characterization

• Kinematic descriptors

– Velocity, 0.2 to 50 mm/s for traffic-induced vibrations (ISO 4866:1990)

• Peak Particle Velocity (PPV)

• Peak Component Particle Velocity (PCPV)

– Acceleration, 0.02 to 1 m/s2 for traffic-induced vibrations (ISO

4866:1990)

• Duration

– Continuous

– Transient

• Frequency content

– Most building damages from man-made sources occur in the frequency

range from 1 Hz to 150 Hz (ISO 4866:1990)

– Some frequency-dependent criteria are available

DIN 4150-3 (UNI 9916)

Building type

Guideline PCPV values for short-term vibrations [mm/s]

Foundation Highest floor

1-10 Hz 10-50 Hz 50-100 Hz All

frequencies

Buildings under preservation

order 3 3-8 8-10

8

(horizontal)

≤ 20

(vertical)

Building type Guideline PCPV values for long-term vibrations [mm/s]

(highest floor, all frequencies)

Buildings under preservation

order

2.5 (horizontal)

≤ 10 (vertical, UNI 9916)

SN 640312 a (UNI 9916)

Building type Guideline PPV values [mm/s]

8-30 Hz 30-60 Hz 60-150 Hz

Historic

buildings

under

preservation

order

Transient

vibration

Between 7.5

and 15

Between 10

and 20

Between 15

and 30

Frequent

vibration

Between 3

and 6

Between 4

and 8

Between 6

and 12

Continuous

vibration

Between 1.5

and 3

Between 2

and 4

Between 3

and 6

Vienna underground metro

• Vibration criteria by Döller et al, 1976

– Construction operations: 0.20 m/s2

– Continuous loading: 0.02 m/s2

– Occasional loading: 0.05 m/s2

California Department of Transportation

Frequency range Guideline PPV [mm/s] values

for transient vibration

Guideline PPV [mm/s] values

for steady-state vibration

1-10 Hz 6.35 3.05

10-40 Hz 6.35-12.70 3.05-6.35

40-100 Hz 12.70 6.35

Building type Guideline PPV [mm/s] values for continuous

vibration

Recommended upper limit of

vibration to which ruins and ancient

monuments should be subjected

2.03

Konon & Schuring, 1985

Whiffin & Leonard, 1971

Underground Diameter Line in Beijing

• Vibration criteria by Jia et al, 2008 (PPV, 1 horizontal & 1 vertical)

– Ming Dynasty City Wall: 1.8 mm/s

– Jingfeng Railway Station Relic and Zhengyang Gate: 3.0 mm/s

Ming Dynasty City Wall Zhengyang Gate Jingfeng Railway Station Relic

GB/T 50452-2008

Allowable Vibration Velocity of Brick Masonry Structure [mm/s]

(peak point of load-carrying structure, horizontal direction)

Preservation level Vp [m/s]

< 1600 1600-2100 > 2100

National Level 0.15 0.15-0.20 0.20

Provincial Level 0.27 0.27-0.36 0.36

City and County Level 0.45 0.45-0.60 0.60

Allowable Vibration Velocity of Stone Masonry Structure [mm/s]

(peak point of load-carrying structure, horizontal direction)

Preservation level Vp [m/s]

< 2300 2300-2900 > 2900

National Level 0.20 0.20-0.25 0.25

Provincial Level 0.36 0.36-0.45 0.45

City and County Level 0.60 0.60-0.75 0.75

Alignment of Metro Line 6 and Line 8 in Beijing

• Vibration criteria by GERB, 2012 from GB/T 50452-2008

– Brick stonework: 0.15 mm/s

– Stone: 0.20 mm/s

– Wood: 0.18 mm/s

Chengdu Subway Line 2

• Vibration criteria by Ma et al, 2011 from GB/T 50452-2008

Selection of vibration criteria for the Colosseum

• Issues

– Effects of, both, long-term and short-term vibrations on the monument

– New underground metro line

• Framework for choosing vibration criteria

– DIN 4150-3 is the most popular standard in this field and its use is also

covered by UNI 9916

– Conclusions drawn for protecting the St. Steven’s Cathedral (Vienna)

are interesting as well, because they were elaborated for a pertinent

case-study

– Allowable velocities indicated by the recent Chinese National Code are

worthy of consideration

• Highest level of protection (“National level”)

• Recent experimental Vp values for tuff, travertine and masonry are available

Wireless dynamic monitoring of the Colosseum

• Sensors

– No. 4 accelerometers PCB, series 393B12, with a sensitivity of 10 V/g

(current sensors)

– Directions (current configuration)

• No. 3 accelerometers along radial direction

• No. 1 accelerometer along vertical direction

– Scalable network

• More measurement points can be added in the future

– Non-destructive mounting

• Each component can be moved without aesthetic damages on the monument

Wireless dynamic monitoring of the Colosseum

Wireless dynamic monitoring of the Colosseum

• Data transmission

– Wireless data transmission

– Spatially re-configurable network

• Data acquisition, storage and access

– User-configurable parameters for data acquisition

– Web-based repository (up to available space)

• Old data can be transferred to a local archive when they exceed the

maximum available space on the web-based repository

– Local (in situ) and remote (by Internet) access

• Power supply

– 9-24 V (batteries)

– Designed for continuous monitoring

– Optimized for low-consumption

Wireless dynamic monitoring of the Colosseum

Concluding remarks

• Modeling heritage buildings under ambient vibrations

– Building components are typically in varying states of deterioration, and

previous settlements and movements in the structure often have

redistributed the loads and stresses into unknown patterns

– Reliability of mechanical models for old and deteriorated masonry

structures under high-cycles dynamic loading is uncertain

• Experimental assessment by dynamic monitoring

– Wireless monitoring offers important advantages in heritage buildings

• Reliability of vibration criteria

– Vibration-based damage criteria are largely empirical

– When establishing a vibration criterion for a project, consideration must

be given to vibration wave characteristics, importance and conditions of

the site and receiving structure, cultural-social-economic impacts, etc.

– Probability-based approaches would be a step forwards