Lifetimes of excited states in 229Th, populated in the β decay of 229Ac, have been measured using the advanced time-delayed βγγ(t) method. Half-lives of 14 states have been determined including 11 of them for the first time. Twenty-seven new γ lines have been introduced into the β-decay scheme of 229Ac based on results of γγ coincidence measurements. Reduced transition probabilities have been determined for more than 70 γ transitions in 229Th. Average |D0| values of 0.029(1), 0.077(3), and 0.024(5) e fm have been deduced for the lowest Kπ=1/2±,3/2±, and 5/2± parity partner bands, respectively. Excited states in 229Th and experimental transition rates have been interpreted within the quasiparticle-plus-phonon model. The half-life of the 3.5-eV, 3/2+ isomeric state is predicted to be about 10 h. Potential energy surfaces on the (β2,β3) plane for the lowest single quasiparticle configurations in 229Th have been calculated using the Strutinsky method.