WSP Dahlia – Empowering Carbon-Optimized Structural Design Through Digital Innovation

Structural engineers often face pressure to deliver early stage design options quickly, leading to techniques which rely on proven results and past project experience. This is a necessary approach in all facets of engineering, but imposes practical (time) limits on the ability to explore low-carbon alternatives.   Traditional tools are time-consuming and reactive—only measuring embodied carbon after a design is complete. This results in missed opportunities to reduce carbon when the cost of change is lowest. Clients may also dismiss sustainable options like timber due to perceived complexity or cost, especially when feasibility studies are constrained by budget or time.  WSP recognized the need for a tool that could empower engineers to lead carbon-based design ideation and conversations from the outset. Our internal studies have shown that a mass timber solution can reduce embodied carbon by up to 40% per square metre of floor area compared to structural steel. Recognizing this potential, we prioritized developing practical tools to support early-stage conversations with architects and building owners—ensuring carbon-conscious decisions are made when they matter most, in the buildings we design, construct, and inhabit every day.  The challenge was to create a solution that could generate carbon-optimized structural systems instantly, with minimal input, and without requiring detailed design work. It had to be fast, flexible, and educational—supporting both internal workflows and client engagement.

WSP Dahlia resolves the challenge of initial design-stage carbon evaluation by enabling engineers to instantly generate and compare structural systems optimized for embodied carbon.   Unlike traditional tools that require system level inputs to assess and provide a carbon estimate, Dahlia uses minimal user-defined criteria that are typically well known at early stages (such as bay size, loading, and gross floor area). The user can then “assemble” the components of their building through selecting material options and preferences for each of the major occupancies to build up the total floor area, and thus, the overall estimate of embodied carbon. These “design options” can then be tweaked and compared to other solutions, in a matter of minutes. Providing instant insights into how different inputs impact the embodied carbon of a building.  Dahlia’s intuitive web-based interface allows engineers to explore multiple framing options quickly and efficiently, without duplicating effort. Each option is evaluated for structural performance and embodied carbon, with built-in checks for vibration, deflection, and fire compliance—ensuring every solution is both practical and code-compliant. Results are presented through clear, interactive tables and charts that support informed, client-facing conversations. Thanks to Dahlia’s agile algorithms, project teams can make real-time adjustments, instantly incorporating client feedback and demonstrating the impact of design decisions on carbon performance.  Dahlia’s transparent methodology and rapid feedback loop make it a powerful tool for both internal use and client engagement—ensuring that informed low-carbon choices at made at critical design stages.