Which structural risk increased with multistory aqueducts such as the Pont du Gard by overlapping arches?

💡 Explanation

When arches overlap in multistory aqueducts the keystone thrust increases, because the load accumulates, concentrating stress on lower piers. Therefore stress concentration results, rather than cracking, seismic effects, or flow reduction which require different mechanisms.

• Which outcome occurred when the chinampa system experienced increased salinity in pre-colonial Mesoamerica maize cultivation?
• Which mechanism enabled medieval Islamic astronomers to accurately predict lunar eclipses after refining Ptolemy's geocentric model?
• Which risk increases when ancient terrace farming systems experience intense rainfall?
• Which ecological consequence resulted from intensive maize cultivation on Mesoamerican chinampa farms during the Aztec empire?
• Which outcome reduces flow capacity most severely when clay-lined Mesopotamian irrigation canals experience excessive silt deposition?
• Which risk increased during 18th century construction of larger wooden warships exceeding material limits?