Bridges in the near future may be able to withstand catastrophic earthquakes by literally “jumping” off the ground and “dancing.” Meanwhile, a nano-polymer may enable building walls to self-heal their cracks. And what exactly does a realistic home of the future look like?

Dancing Constructs
With natural disasters such as earthquakes and tsunamis laying waste to towns and infrastructure throughout the world — from the United States West Coast to Southeast Asia — many skyscrapers are being built to withstand huge pressures.

For example, working with super-strong materials that can bend, stretch and compress without breaking, scientists and engineers at Lehigh University last year tested a next-generation “self-centering” system that uses gigantic steel bands to hold building columns and beams in place during an earthquake. As IMT previously noted:

In allowing the beams and columns to separate, rock and twist independently of one another, the rope-like steel bands — encased in plastic — are meant to prevent a building frame from buckling during an earthquake. The system also uses friction plates that help dissipate the quake’s energy. After the tremors subside, the steel bands pull the beams and columns back to their original positions.

Lehigh’s Center for Advanced Technology for Large Structural Systems (ATLSS) Engineering Research Center’s structural testing lab, where scientists have tested a next-generation “self-centering” system for buildings during earthquakes
Credit: AP/ABC News

More recent, researchers at the University of Buffalo in upstate New York last month announced the development and successful testing of the first seismic design methodology for bridge towers that respond to ground motions by literally “jumping” a few inches off the ground.

The university’s engineers developed a design procedure in which the steel truss tower’s legs, anchored strongly to their footing, are disconnected from their base and briefly uplifted by a small amount if significant ground motions occur. The methodology will not allow uplifts to exceed limits considered safe by the design procedure and dictated by the tower design, local conditions and the need for the tower to return safely to its original position.

During a series of tests on a state-of-the-art “shake table,” the experimental truss tower fitted with devices hysteretic or viscous dampers — which were inserted at the base of the towers to allow the tower to rock while absorbing part of “the earthquake” energy — was subjected to ground motions simulating the 1994 Northridge, California earthquake. (Testing also was conducted without any devices attached.) During testing, the tower’s legs typically uplifted nearly two inches in the air for less than a second. For some of the free-rocking cases, the tower legs lifted nearly four inches.

All of the tests were successful.

Although engineers previously have employed the concept, such as in the approach spans of the Lions Gate Bridge in Vancouver, British Columbia, the University of Buffalo methodology is the first to be established for this application.

“Professional engineers are starting to recognize that it is economical to allow this type of rocking in their designs, as long as the structure remains stable and the speed with which the legs come down is carefully controlled to minimize the forces that develop during the rocking,” said Michel Bruneau, Ph.D., director of MCEER and University of Buffalo professor of civil, structural and environmental engineering, who developed the new approach with Michael Pollino, a doctoral candidate in the university’s Department of Civil, Structural and Environmental Engineering.

These “bridges that ‘dance’ during earthquakes could be the safest and least expensive to build, retrofit and repair,” according to earthquake engineers at the university and MCEER.

(See also: “Shape-shifting Structures Adapt to Environment” and “Shake, Rattle, Roll: Advances In Earthquake-Proof Buildings”)

Self-Healing House
A high-tech villa designed to resist earthquakes by “self-healing” cracks in its own walls and monitoring vibrations through an intelligent sensor network will be built on a Greek mountainside.

The house walls will be built from novel load bearing steel frames and high-strength gypsum board. They will also contain wireless, battery-less sensors and radio frequency identification (RFID) tags that collect vast amounts of data about the building over times, such as any stresses and vibrations, temperature, humidity and gas levels.

According to the University of Leeds:

The University of Leeds’ NanoManufacturing Institute (NMI) will play a crucial role in the