Reliability-based design method of suppressing chloride ingress for reinforced concrete buildings located in coastal regions of Taiwan

Abstract

The main purpose of this work is to propose an estimating procedure that building designers can use to choose methods of suppressing chloride ingress, i.e. concrete-cover thickness, concrete-surface coating and concrete mix (water–cement ratio), for reinforced concrete (RC) buildings with a specified durability performance. At first, the authors build equations for estimating airborne chloride concentrations in coastal regions in Taiwan by regressing measurement data. Then, an analytical model incorporates these data into a deterioration model for chloride-induced corrosion and to estimate corrosion of reinforcing steel bars. This work also presents a novel computational procedure to calculate the risk of corrosion for reinforcing steel bars embedded in concrete, while considering uncertainties in environmental conditions, material properties and model error. Using risk curves of corrosion, building designers can set an allowable durable reliability to determine the minimal required concrete-cover thickness for RC members. Finally, this work adopts coastal regions in Taiwan as an example to determine the minimum required concrete-cover thicknesses. Furthermore, reliability-based methods of suppressing chloride ingress for RC buildings are also suggested for each division zone of Taiwan.