𝐖𝐡𝐲 𝐚𝐫𝐞 𝐢𝐧𝐭𝐞𝐫𝐧𝐚𝐥 𝐟𝐨𝐫𝐜𝐞𝐬 𝐢𝐧 𝐬𝐡𝐞𝐚𝐫 𝐰𝐚𝐥𝐥𝐬 𝐟𝐫𝐨𝐦 𝟑𝐃 𝐫𝐞𝐬𝐩𝐨𝐧𝐬𝐞 𝐬𝐩𝐞𝐜𝐭𝐫𝐮𝐦 𝐚𝐧𝐚𝐥𝐲𝐬𝐢𝐬 𝐦𝐮𝐜𝐡 𝐥𝐨𝐰𝐞𝐫 𝐭𝐡𝐚𝐧 𝐟𝐫𝐨𝐦 𝐡𝐚𝐧𝐝 𝐜𝐚𝐥𝐜𝐮𝐥𝐚𝐭𝐢𝐨𝐧?

That topic keeps coming up from engineers who are starting to use #3Dseismicanalysis for buildings. Inevitably, a student asked me that very question just a couple of weeks ago… FEA users are always encouraged to first carry out a simple #handcalculation before running a complex 3D analysis. One should always…