ABSTRACT
The importance of bridges as the most vulnerable components of traffic networks in earthquakes, and the fact that bridge failures typically result in fatalities, traffic disruption, and expensive and lengthy repairs, causes to demand of earthquake resilient bridges. On the other hand, corrosion weakens structural elements and increases their vulnerability to seismic events. Therefore the investigation on the effects of corrosion on seismic performance of structures and structural elements is critical. In this paper seismic performance of two structural systems employed in bridge piers called high damage (fixed pier to foundation connection) and low damage (controlled rocking connection) subjected to corrosion have been experimentally compared. The objective is evaluation of robustness of advanced bridge construction (ABC) technology including low damage seismic resistance (innovative solution to use of ABC in high seismicity regions) subjected to corrosion and earthquakes with the high damage bridge piers.
Regarding high damage bridge pier, the reinforcing steels embedded in concrete are the most vulnerable components in corrosion attacks. Therefore, in this paper the effects of corroded reinforcing steels on seismic performance of the socket connection RC bridge pier have been experimentally studied. To meet this aim, the well-known accelerated corrosion method called galvanostatic method was employed to corrode two RC bridge piers with 500 mm diameter and 3000 mm height with two different corrosion levels. Then quasi static cyclic tests on a noncorroded and two corroded RC bridge pier have been carried out.
As far as low damage bridge pier is concern, the external dissipaters are the most vulnerable components in corrosion attacks. To corrode the dissipaters the galcvanostatic method employed. Then the effects of corroded external dissipaters on seismic performance of the rocking bridge pier have been experimentally studied.
The results clearly show corrosion induced deterioration significantly affect seismic performance of the RC bridge piers indicating life time seismic analysis of bridges are critically essential to evaluate structural performance of existing and design of new bridges. However post-tensioned rocking connection with replaceable external dissipaters are more robust connection for bridge piers subjected to corrosion if compared with the high damage connection. It should be emphasis that only corrosion of external dissipaters can influence the structural and seismic performance of the bridge pier. The corroded external dissipaters can be replaced easily.
Figure 1 illustrated the effects of corrosion of the dissipaters on the lateral force-drift response of the rocking bridge pier. The results clearly confirmed that corrosion of dissipater have a vital effects on seismic performance of bridge pier. The tests were terminated when the first dissipater was ruptured. Horizontal force-drift of the rocking bridge pier with corroded and non-corroded dissipaters. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig220_1.tif"/>
Figure 2 illustrated the effects of corrosion of the plastic hinge region of the high damage bridge pier on the lateral force-drift response. The results clearly confirmed that corrosion of steel reinforcement in the region plastic hinge region was formed significantly 423effects on seismic performance of the high damage bridge pier. The tests were terminated when the the maximum lateral force was diminished by at least 20%. Horizontal force-drift of the corroded and non-corroded high damage bridge pier. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig220_2.tif"/>
