SUMMARY This work presents a new seismic evaluation methodology for corroded reinforced concrete bridges on the basis of nonlinear static pushover analysis. Corrosion of steel reinforcement by chloride attack is considered. At the material level, the effects of corrosion are considered by modeling the degradation of the mechanical properties of steel reinforcement, softening of cover concrete under compression, degradation of core concrete due to confinement steel corrosion, and reduction of bond strength between concrete and steel reinforcement. At the structural level, the effects of corrosion on both flexural behavior and shear behavior, and their interaction are considered. Eleven bridges of various structural types in Taiwan that are located within 6.5 km of their nearest coastline are analyzed to identify their long‐term seismic performance. Relationships between the yield and collapse peak ground accelerations (PGAs), and service time and corrosion level are established for each bridge. Analysis results show that chloride corrosion starts in 2–32 years. The transverse steel reinforcement typically starts corroding before the longitudinal steel reinforcement, as the former has a thicker cover. Research results show that collapse PGA reduces by 0.94% or 1.23% per 10 years when the mean value plus 1 or 2 standard deviation of the collapse PGA values are considered, respectively. Therefore, we suggest increasing the design PGA from 4.70% to 6.15% for a bridge adjacent to a coastline to ensure adequate long‐term seismic performance for 50 years, the typical design life span of a regular bridge. Copyright © 2013 John Wiley & Sons, Ltd.

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This study investigated experimental bearing capacity of corroded reinforced concrete beams. Six testing beams were made of concrete having compressive strength of 25 MPa, with the dimensions of 1200 x 80 x 120 mm. They were divided into two groups depending of tension reinforcement ratio. Of which, two beams were used as the controls, whereas the other fours ones having tension reinforcement were subjected to corrosion by the electrochemical accelerated corrosion method. After accelerated corrosion, the beams were tested under monotonic loading to investigate their performance. All the tested beams were failed in flexural failure mode corresponding to spalling of cover concrete. Test results showed that as corrosion rate in tension reinforcement increased, the lower cracking load and the displacement at the cracking load were observed. As the corrosion rate of tension reinforcement ranging from 7.5% to 8.3%, it had little effect on the peak load. As the corrosion rate increased further, approximately 10.8% and 14.1% in this study, the peak load decreased significantly. The higher the corrosion rate, the lower the displacement of corroded beams. Moreover, as corrosion rate of tension reinforcement increased the number of concrete cracks and their spacing reduced, and the width of cracks was generally larger. Keywords: reinforced concrete beam; electrochemical accelerated corrosion; corrosion rate; load-carrying capacity; displacement; concrete cracking. Received 08 January 2019, Revised 16 January 2019, Accepted 17 January 2019

We report a numerical study on mid-infrared (IR) supercontinuum (SC) generation in the regime of all normal dispersion using lead bismuth gallate glass photonic crystal fiber. This fiber allows the changing of dispersion from anomalous dispersion to ultra-flat normal dispersion in the wavelength range of over 930 nm by filling its cladding holes with C2Cl4. Using a 12.5 kW laser pulse at 2.8 µm as a pump source, we demonstrate that a broad and highly coherent SC generation spectrum is generated in the wavelength range of 1.2 μ m –3.4 μ m with the effects of vacuum noise. However, pulse-to-pulse relative intensity noise significantly decreases the coherence. These interesting optical properties make the proposed C2Cl4—infiltrated fiber highly promising for various applications in the mid-IR regime, particularly, spectroscopy, optical coherence tomography, and metrology.

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