Reinforced of Piers of a Bridge Type Using Fragility Curves

Abstract eng:
Most of the existing bridges in Mexico were built 30 years ago or more (similar to that of other countries), so maintenance and reinforced programs are necessary to rehabilitate old structures before earthquakes take place. To define the best rehabilitation technique depends on the bridge type, damage degree of the elements, earthquake characteristics and economic aspects. Most of the time, the reinforcement condition is decided for each special case. This paper presents a reinforcement procedure to define the best rehabilitation technique of piers of a bridge type, with single wall pier by bent. The best rehabilitation technique is defined in function of probabilistic aspects, using fragility curves. To do this, mechanical properties of the piers material are considered as random variables with probabilistic distribution function, mean and variation coefficient are considered from the available literature. Also, earthquake load is random considering four seismic scenarios and artificial records. For the original structures the fragility curves were defined by means of a Monte Carlo simulation for the four seismic scenarios. Damage is represented by the local and global Park indices. Then, light, moderate and severe damage were simulated in most earthquake susceptible pier. Damage is simulated considering degradation of pier section in function of experimental test reported in literature. For example, light damage, almost 10% of degradation, is represented by the same original section without concrete cover, because it was observed in experimental test of piers elements that the concrete cover is lost in a few cycles. For damaged structures fragility curves were again determined. Degraded bridges were reinforced using conventional techniques, specifically steel, concrete and fiber jackets, only for the damaged piers. The dimensions of the jackets were first selected considering that the fragility curves of these structures were similar to the ones of the original bridges. But it was not always possible; for example the minimum thick recommended produces a null damage index in the most of the Monte Carlo simulation of elements with light damage. Fragility curves of original, damaged and reinforced bridges were compared. Through this comparison, the best option to reinforce the bridge piers is selected, and some practical recommendations were expressed.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket