Design World

  • Home
  • Technologies
    • 3D CAD
    • Electronics • electrical
    • Fastening & Joining
    • Factory automation
    • Linear Motion
    • Motion Control
    • Test & Measurement
    • Sensors
    • Fluid power
  • Learn
    • Ebooks / Tech Tips
    • Engineering Week
    • Future of Design Engineering
    • MC² Motion Control Classrooms
    • Podcasts
    • Videos
    • Webinars
  • LEAP AWARDS
  • Leadership
    • 2022 Voting
    • 2021 Winners
  • Design Guide Library
  • Resources
    • Subscribe!
    • 3D Cad Models
      • PARTsolutions
      • TraceParts
    • Digital Issues
      • Design World
      • EE World
    • Women in Engineering
  • Supplier Listings

How Engineers are Straightening the Leaning Tower of Pisa

By Sonia Logre And Charles Onians | December 4, 2018

Share

“It’s still straightening,” said engineer Roberto Cela, gazing at the Leaning Tower of Pisa gleaming in the autumn sunshine of northern Italy. “And many years will have to pass before it stops.”

The gravitationally-challenged landmark is leaning less after years of ambitious engineering work. Fortunately for the millions of tourists who come here every year, the 57-metre (186-feet) tower remains beautifully askance.

The medieval bell tower, a symbol of the power of the maritime republic of Pisa in the Middle Ages, has leaned to one side ever since building started in 1173 on ground that proved a little too soft.

The tower was closed to the public in January 1990 for 11 years over safety fears, as its tilt reached 4.5 meters (15 feet) from the vertical, threatening to turn it into a pile of rubble.

“We installed a number of tubes underground, on the side that the Tower leans away from,” said Cela, technical director at the OPA, which looks after Pisa’s main monuments.

“We removed soil by drilling very carefully. Thanks to this system, we recovered half a degree of lean,” he said.

Michele Jamiolkowski, an engineer of Polish origin who adopted Italian nationality, coordinated an international committee to rescue the landmark between 1993 and 2001.

Engineering lecturer Nunziante Squeglia of Pisa University, who works with the Surveillance Group that was set up after the rescue work, has been studying and measuring the tower for 25 years.

He says that the tower straightened by 41 centimetres (16 inches) until 2001, and another four centimetres since then.

Still mysterious

To understand how the 14,500-tonne building is moving, measurements are made as often as once an hour, some automatically using pendulums, some manually using a surveyor’s optical level.

“The tower tends to deform and reduce its lean in the summer, when it’s hot, because the tower leans to the south, so its southern side is warmed, and the stone expands. And by expanding, the tower straightens,” said Squeglia.

He explains that there are three pendulums, one dating back to 1935, when systematic measurements began, although annual measurements began as far back as 1911.

“The tower was much more mysterious when I arrived, it wasn’t clear why it was leaning, and increasingly leaning,” said Squeglia.

“It is a building that has been extensively studied for over 100 years but there are still so many things to know,” he said, including the remains of what looks like a domed roof inside the tower that is still unexplained.

Meanwhile, Cela predicted that the tower “will never be completely straight”.

“When they were building it, there were attempts to straighten it (by adding stone on one side), so it has a slight banana shape.”

Singaporean tourist Alvin, who like many visitors is taking photos of friends ‘holding up’ the tower in the background, said he didn’t know about the decreased lean.

“Oh I didn’t notice, is it because like everyone’s pushing against it?” he said, promising to try to push the tower back if it straightens too much.

“Don’t worry, it’ll never be ‘completely straight'”


Filed Under: Rapid prototyping

 

Related Articles Read More >

PCB mills
Basics of printed circuit board milling machines
Rapid Product Solutions, Inc. enhances its rapid prototyping and production services
Protolabs Launches Production Capabilities for Metal 3D Printing
3D Printer Makes Peacekeeping Missions Cheaper and Repair of Defense Systems Faster

DESIGN GUIDE LIBRARY

“motion

Enews Sign Up

Motion Control Classroom

Design World Digital Edition

cover

Browse the most current issue of Design World and back issues in an easy to use high quality format. Clip, share and download with the leading design engineering magazine today.

EDABoard the Forum for Electronics

Top global problem solving EE forum covering Microcontrollers, DSP, Networking, Analog and Digital Design, RF, Power Electronics, PCB Routing and much more

EDABoard: Forum for electronics

Sponsored Content

  • Industrial disc pack couplings
  • Pushing performance: Adding functionality to terminal blocks
  • Get to Know Würth Industrial Division
  • Renishaw next-generation FORTiS™ enclosed linear encoders offer enhanced metrology and reliability for machine tools
  • WAGO’s smartDESIGNER Online Provides Seamless Progression for Projects
  • Epoxy Certified for UL 1203 Standard

Design World Podcasts

July 26, 2022
Tech Tuesdays: Sorbothane marks 40 years of shock and vibration innovation
See More >
Engineering Exchange

The Engineering Exchange is a global educational networking community for engineers.

Connect, share, and learn today »

Design World
  • Advertising
  • About us
  • Contact
  • Manage your Design World Subscription
  • Subscribe
  • Design World Digital Network
  • Engineering White Papers
  • LEAP AWARDS

Copyright © 2022 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search Design World

  • Home
  • Technologies
    • 3D CAD
    • Electronics • electrical
    • Fastening & Joining
    • Factory automation
    • Linear Motion
    • Motion Control
    • Test & Measurement
    • Sensors
    • Fluid power
  • Learn
    • Ebooks / Tech Tips
    • Engineering Week
    • Future of Design Engineering
    • MC² Motion Control Classrooms
    • Podcasts
    • Videos
    • Webinars
  • LEAP AWARDS
  • Leadership
    • 2022 Voting
    • 2021 Winners
  • Design Guide Library
  • Resources
    • Subscribe!
    • 3D Cad Models
      • PARTsolutions
      • TraceParts
    • Digital Issues
      • Design World
      • EE World
    • Women in Engineering
  • Supplier Listings