Low carbon solution for short-span bridges: Soil-steel composite bridges versus concrete bridges

Soil-steel composite bridges (SSCB) are extensively utilized for constructing culverts and small-span bridges in numerous countries worldwide, particularly in Europe and North America. The widespread adoption of SSCBs is attributed to their various advantages, such as swift construction, easy installation, low maintenance, straightforward renovations or extensions, and high geometric flexibility, enabling seamless adaptation to terrain conditions and functional requirements. An alternative solution for such structures is the use of reinforced concrete bridges (RCB), including concrete boxes, slabs, frames, or beams bridges. Under the global shift towards a low-carbon strategy and reduction of greenhouse emissions from the transport sector, assessing potential solutions for culverts or small bridges, it is essential to consider their environmental impact. And this is a practice increasingly common across various economic sectors, including engineering.
This paper aims to compare the environmental impact of SSCBs and RCBs by analyzing selected 29 equivalent case studies from several European countries using the cradle-to-gate Life Cycle Assessment (LCA) methodology. Two key environmental impact indicators are selected for evaluation: global warming potential and energy consumption. Data for the analysis of these indicators are derived from Environmental Product Declarations (EPD) and the environmental database Ecoinvent v.3.8.
The case studies demonstrate the advantages of soil-steel bridges over reinforced concrete bridges in the chosen environmental indicators. The main reason for the superior performance of SSCBs lies in their highly efficient use of material mass to ensure the same functionality and load capacity comparing to the concrete solutions. The main load-bearing component of SSCBs is a thin and lightweight corrugated steel plate, which acts as a flexible shell interacting effectively with the surrounding compacted soil. This solution significantly reduces overall resource consumption and carbon emissions.