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A new
earthquake-resistant concrete frame with fiber-reinforced
plastic fabrics and shifted plastic hinges
M. Saiid Saiidi, Erik Reinhardt and Faramarz Gordaninejad |
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Vol. 4 (2009), No. 5, 927–940
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Abstract |
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An innovative structural pier employing concrete, steel, and carbon fiber composite sheets was developed and implemented in a two-column bridge pier. The basic concept for the pier design is that the pier has preassigned plastic hinges in the columns. Outside the plastic hinges, the pier is to remain elastic. The innovative concept incorporated in the pier is that where plastic hinging and ductility is required, steel reinforcement is used as longitudinal reinforcement, and where elastic behavior is required, carbon-fiber-reinforced plastic (CFRP) sheets are used as longitudinal reinforcement. Confinement and shear capacity are provided for by fiber-reinforced polymer sheets at all locations. The pier is detailed so that the plastic hinges are shifted away from the column ends because shifted plastic hinges prevent damage from penetrating into the joint area and are easier to repair. A quarter-scale, two-column pier with square columns was designed and constructed based on the aforementioned concept. Ordinary concrete and mild steel were used in the pier. A unidirectional carbon composite was placed on the pier. The pier was studied using computer programs DRAIN 3-DX and RC-Shake and a shake table testing program was developed. The pier was subjected to successive runs of the 1994 Northridge–Sylmar record with increasing amplitudes until failure. The plastic hinges behaved as planned, and the failure occurred after the rupture of the CFRP confinement sheets at one of the plastic hinges. There was no apparent damage outside the plastic hinges. Extensive nonlinear analytical studies using multiple- and single-degree-of-freedom modes were conducted and the results were compared with the measured response. It was found that both models were generally capable of reproducing the experimental results. |
Keywords
bridges, carbon fiber, earthquake, nonlinear analysis,
offset hinges, piers, shake table testing
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Milestones
Received: 8 March 2009
Revised: 16 May 2009
Accepted: 17 May 2009
Published: 5 September 2009
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Authors |
| M. Saiid Saiidi | |
| Department of Civil and
Environmental Engineering University of Nevada Reno, NV 89557 United States |
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| Erik Reinhardt | |
| Halcrow-Yolles Structural
Engineers 5550 W Flamingo Road Las Vegas, NV 89103 United States |
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| Faramarz Gordaninejad | |
| Department of Mechanical Engineering
(MS 312) University of Nevada Reno, NV 89557 United States |
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