Generative design for more economical and environmentally sustainable reinforced concrete structures

With billion tons of carbon dioxide emitted by the construction and manufacturing sector every year, there is an urgent need for reducing construction materials consumption as the construction industry continues to grow. Current practices for designing structural elements, which are based on traditional design methods, result in building box-shaped elements and consuming more materials than what is structurally necessary. Excess materials can be removed without compromising the structural soundness of the elements while also providing added architectural value. This paper presents an approach based on generative design concepts, genetic algorithms, and the Lagrangian Multiplier Method to design concrete beams that use near-exact amounts of material only where they are needed. In this study, beam designs are optimized to reduce concrete and steel use in reinforced concrete beams. The effectiveness of the approach was demonstrated through its deployment to design a cantilever beam and a simply supported beam. The results of both applications were very promising as the reductions in material costs reached 63% and the related reductions in CO2 emissions reached 57% per beam. This lays strong foundations for expanding the effort to scale this approach into entire buildings. The optimized structures can be constructed using 3D concrete printing technology, which eliminates the barriers imposed by traditional form-based construction. The results of this study contribute to means for making construction more economical and environmentally sustainable. © 202

Credit Rating Agency Announcements and the Eurozone Sovereign Debt Crisis

This paper studies the impact of credit rating agency (CRA) announcements on the value of the Euro and the yields of French, Italian, German and Spanish long-term sovereign bonds during the culmination of the Eurozone debt crisis in 2011-2012. The employed GARCH models show that CRA downgrade announcements negatively affected the value of the Euro currency and also increased its volatility. Downgrading increased the yields of French, Italian and Spanish bonds but lowered the German bond's yields, although Germany's rating status was never touched by CRA. There is no evidence for Granger causality from bond yields to rating announcements. We infer from these findings that CRA announcements significantly influenced crisis-time capital allocation in the Eurozone. Their downgradings caused investors to rebalance their portfolios across member countries, out of ailing states' debt into more stable borrowers' securities

The Power of Opinion: More Evidence of a GIPS-Markup in Sovereign Ratings During the Euro Crisis

This paper examines whether the Big Three credit rating agencies actually played as active a role in the Euro Crisis as previously asserted. On the basis of panel data methods for a set of 11 EMU countries, the analysis reveals significant evidence for an arbitrary markup on the GIPS group of countries across agencies. This markup, which ranges from 1.5 notches for Moody's to 2.2 notches for S&P, suggests that GIPS countries were treated worse than other EMU members since the start of the Eurozone crisis in 2009, irrespective of economic and institutional fundamentals. A subsequent analysis of the markup's effect on yield spreads shows that this markup had significant effects on financial markets, leading to risk premiums for these countries of up to 1.6 points