Seismic design of reinforced concrete frames for minimum embodied CO 2 emissions

Abstract

Optimum structural design of reinforced concrete (RC) frames has been the focus of extensive research. Typically, previous studies set economic cost as the main design objective despite the fact that RC structures are major contributors of CO2 emissions. The limited number of studies examining optimum design of RC frames for minimum CO2 emissions do not address seismic design considerations. However, in many countries around the world, including most of the top-10 countries in CO2 emissions from cement production, RC structures must be designed against earthquake threat. To bridge this gap, the present study develops optimum seismic designs of RC frames for minimum cradle to gate embodied CO2 emissions and compares them with optimum designs based on construction cost. The aim is to identify efficient design practices that minimize the environmental impact of earthquake-resistant RC frames and examine the trade-offs between their cost and CO2 footprint. To serve this goal, an RC frame is optimally designed according to all ductility classes of Eurocode 8 and for various design peak ground accelerations (PGAs), concrete classes and materials embodied CO2 footprint scenarios. It is found that the minimum feasible CO2 emissions of RC frames strongly depend on the adopted ductility class in regions of high seismicity, where low ductility seismic design can generate up to 60% more CO2 emissions than designs for medium and high ductility. The differences reduce, however, as the level of seismicity decreases. Furthermore, CO2 emissions increase significantly with the design PGA. On the other hand, they are less sensitive to the applied concrete class. It is also concluded that, for medium to high values of the ratio of the unit environmental impact of reinforcing steel to the respective impact of concrete, the minimum CO2 seismic designs are very closely related to the minimum cost designs. However, for low values of the same ratio, the minimum cost design solutions can generate up to 13% more emissions than the minimum CO2 designs.

Factors in the Relationship Between Optimal CO2 Emission and Optimal Cost of the RC Frames

“…It should be noted that the addition of transverse reinforcement to achieve higher ductility capacity for high and medium ductility classes does not significantly increase the CO 2 emissions and the optimal cost. This is due to their lower contribution in the cost and total CO 2 emissions [22]. Therefore, in this study, only the effect of behavior factor R has been investigated for all ductility classes.…”

“…Park et al [21] developed an integrated analysis model for minimizing of carbon dioxide emissions, seismic performance, and costs of RC frames through performance-based optimal seismic design. Mergos [22] has identified efficient design methods that minimize the environmental impact of seismic resistant frames. In which a three-story two-span RC frame is optimally designed for all ductility classes according EC8 and for various design peak ground accelerations (PGAs), concrete classes and material embodied CO 2 footprint scenarios.…”

Evaluation of CO2 emission reduction effect using in-situ production of precast concrete components

“…Presently, problems associated with CO 2 emissions have gained massive attention, resulting in several international regulations being developed on greenhouse gas emissions (Giesekam, Taylor, and Owen 2014;Sartori and Hestnes 2007;Yu and Kim 2011). For this reason, researches to reduce CO 2 emission via the use of sustainable technologies are being continuously performed in the construction area (Ecoinvent 2019;Giama 2016;Jeong, Hong, and Kim 2018;Lee 2014;Mergos 2018). Yepes, Martí, and García-Segura (2015) proposed a methodology to optimize CO 2 emissions for road designs using PC components, and they developed a hybrid glowworm swarm optimization algorithm.…”

Dynamic Optimization Model for Estimating In-Situ Production Quantity of PC Members to Minimize Environmental Loads

“…CO 2 accounts for 80% of greenhouse gases, and the problem of CO 2 emission becomes more and more prominent [4]. In particular, research on sustainable technologies to reduce CO 2 emission among environmental loads is continuously being conducted [5][6][7][8][9]. The construction industry is recognized as a major cause of environmental pollution [10], and it is important to quantify and evaluate the environmental load.…”