Optimal retrofit for a school under seismic hazard including risk assessment

ABSTRACT

The paper proposes a formulation to select the optimal retrofit strategy for a damaged school under seismic hazard, by applying risk and reliability assessment techniques. The formulation considers the cost-effectiveness of alternative retrofit strategies, including failure consequences, to get adequate balance (CE: Balance is an uncountable noun) between the costs and the gains on reliability. The proposed alternatives should produce a failure probability below the target value, which is obtained by minimising the present value of the expected life-cycle cost. The failure consequences include the potential life loss, injuries, expenditures due to off-campus resumption of classes and loss/damage of contents. Exceedance of the shear force and bending moment capacities and the allowable inter-story drift are the considered limit states. A relationship between the cost and the increment on reliability is proposed and calibrated for the case study; MCS is applied to calculate the failure probabilities. An example of a two-story building is a school located in the Tlaxcala State; for this case, the target failure probability is 1.6 × 10⁻⁴. The optimal retrofit strategy is the one that corresponds to the minimum expected life-cycle cost. The proposal may serve to generate risk, reliability and resilience-based retrofit recommendations for schools under seismic hazard.

KEYWORDS:

• Optimal upgrading
• structural reliability
• expected life-cycle costs
• seismic hazard
• school structures

Acknowledgements

The first author thanks the UAEM and UPAEP, both in Mexico, for making possible his postdoc stay at the UPAEP, to perform the research work supporting this paper.

Both authors thank INIFED, Mexico for providing the information on the school that served as an example to illustrate the proposed formulation.

Disclosure statement

No potential conflict of interest was reported by the author(s).