대한과 덩치가 참석하지 못한 연수회와 MT 동안, 벌써 부도 다 짜여져 있었고, 각 부마다 팀웍도 잘 다져져 있었다. => During the field trip and membership training that 대한 and 덩치 missed, all departments were all set up, with their working teams already in place and functioning. * 다져져 = contraction of 다지어지다 = 다지다 (vt - harden, strengthen, vet) + 아/어 + 지다(suffix indicating a passive verb). * 잘 다져져 있었다 = 잘(well, thoroughly) 다지어져(have/had been set up/vetted) 있었다(was in a state) = was/had been fully vetted. The sentence is not a particularly good one from a grammar viewpoint. It is using 짜여져/다져져 있었다, which corresponds to the past perfect tense in English, with 동안, which is the same as "during". Just as you wouldn't say something like "During this period, the work had been done", "MT 동안 ... 잘 짜여져 있었다" doesn't sound like proper Korean.

짜여져(짜여지어)= Be well organized 다져져(다져지어)= Be grounded hardly