Probabilistic risk analysis of building columns to gas pipeline explosions

The failure of natural-gas pipelines often induces heavy damage to buildings. Proper safety distances should thus be defined as land-use policy to ensure that an acceptable risk level is not exceeded. In this paper, such an issue is addressed for existing reinforced concrete framed buildings. A probabilistic risk analysis procedure is proposed to estimate the annual probability of damage to reinforced concrete columns associated with high-pressure natural- gas pipeline explosions. Physical features such as the gas jet release process, flammable cloud size, blast generation and propagation, and explosion effects on building columns are considered and evaluated through the SLAB integral model, multi-energy method and structural blast fragility surfaces. Failure probability is estimated through Monte Carlo simulation where the main uncertainties are taken into account. Minimum pipeline-to-building safety distances are derived in several environmental conditions, allowing a risk- informed land-use planning and performance-based design/assessment of pipelines and buildings.