Social Impact Assessment and Comparative Life Cycle Analysis of a Post-Tensioned Slab Bridge

The construction industry accounts for a substantial share of global environmental impacts; therefore, it is essential to incorporate quantitative tools into the decision-making process during infrastructure design. This study applies a comprehensive cradle-to-grave Life Cycle Assessment (LCA) and a Social Life Cycle Assessment (S-LCA) to 31 design alternatives for the deck of a post-tensioned concrete viaduct located in Cocentaina (Alicante, Spain). Modeling was carried out using OpenLCA, employing the SOCA v2 and Ecoinvent v3.7.1 databases together with the ReCiPe 2016 impact assessment method to quantify social and environmental indicators. These indicators were subsequently integrated using the CRITIC objective weighting method to obtain a comprehensive sustainability ranking of the analysed alternatives. The results show that the manufacturing stage is the main source of the overall environmental impacts. The integrated sustainability assessment identified the same bridge deck alternative as the environmental assessment, whereas a different solution achieved the best social performance. Generally, the proposed framework offers a practical and reproducible decision-support tool for integrating environmental and social criteria into bridge design during the early stages of infrastructure development.