Comparison of mass-timber and RC buildings in terms of seismic performance, LCA, and cost in Türkiye

The two devastating earthquakes of 6 February 2023 in Kahramanmaraş, Türkiye, highlighted the poor seismic performance of many existing reinforced concrete (RC) buildings and created an urgent need for rapid, large-scale reconstruction. This study evaluates the feasibility of using a modern mass-timber structural system as an alternative to conventional RC construction for mid-rise residential buildings in Turkish seismic regions. A seven-story residential building was designed in two forms – one with a standard RC shear-wall structure and one with an equivalent mass-timber (cross-laminated timber, CLT) structure – and compared their seismic performance, environmental impacts, and construction costs. Nonlinear static (pushover) and response spectrum analyses were conducted for both designs in accordance with applicable seismic design standards. A cradle-to-gate life-cycle assessment (LCA) was performed to quantify embodied carbon and energy, and a cost analysis was carried out using local 2023 material prices. The CLT building achieved adequate seismic performance, with fundamental periods about twice as long as the RC building and base shear forces roughly one-third as large. Although the CLT structure experienced larger lateral drifts, these remained within serviceable limits. In terms of sustainability, the mass-timber design showed dramatically lower environmental impacts – roughly an order of magnitude reduction in embodied carbon and energy – compared to the RC design. The primary trade-off was economic: due to current material pricing and supply constraints, the mass-timber building’s estimated construction cost was approximately 5–6 times higher than the RC building. Overall, the results indicate that mass-timber is a structurally viable and environmentally advantageous option for post-earthquake reconstruction of mid-rise buildings in Türkiye, provided that issues of cost and material supply can be addressed through future policy and market developments.