Bridge Infrastructure Protection: Regions of High Seismicity
Concrete / Steel Bridge Girders (Concrete-Encased Steel Girders)
Our retrofitted concrete-encased steel girders, re-loaded in four-point bending after initially experiencing catastrophic failure, can sustain over 68% of their peak strength. The initially damaged girders experienced substantial crushing of their mid-span compression zone in addition to fracturing of 50% of the web depth of the encased steel girders. The disintegrated concrete region was then repaired and retrofitted using our innovative scientific technology. See images below.
Upon re-testing, our system allowed the retrofitted girders to absorb the release of the initial shock energy of fractured welds (re-fracturing) and crushed concrete to suddenly intercept the internal crack propagation. To put this ground-breaking result into perspective, a very similarly damaged and conventionally retrofitted girder using a high-strength carbon-fiber composite (carbon-fiber reinforced polymer, CFRP) experienced immediate failure when the reloaded CFRP-retrofitted girder reached its peak strength, correlating to the initial fracturing of the repaired welds and failing to demonstrate any realistic displacement ductility. In comparison, the ultimate displacement of the PowerPolymer-retrofitted girder was three times larger than its CFRP-retrofitted counterpart. See images below.
Severe damage of concrete-encased steel specimens with large fracture following large ground motion (seismic); maximum deflection of C-IDA-retrofitted girder, showing no de-bonding; and experimental load-mid span deflection responses of C-IDA and CFRP – retrofitted girders, where C-IDA is able to blunt the sudden formation of crack surfaces following dynamic fracturing of the steel web welds at peak load, resulting in tremendous strength sustainability and ductility.