Correction: Fujii, K. Bidirectional Seismic Energy Input to an Isotropic Nonlinear One-Mass Two-Degree-of-Freedom System. Buildings 2021, 11, 143

There was an error in the original publication [1]. Two equations in Appendix A (Equations (A11) and (A12)) are incorrect.

A correction has been made to Appendix A:

$$\widehat{e_{I,BI}}=-\frac{1}{2}\left\{\dot{d}{\left(t\right)}^T{a}_g\left(t\right)+{\dot{d}}^{*}{\left(t\right)}^T{a}_g{}^{*}\left(t\right)\right\},$$

(A11)

$$\{\begin{array}{l}\dot{d}\left(t\right)=-{\displaystyle \sum _{n=-N}^N\left\{\begin{array}{c}{c}_{X,n}\\ c_{Y,n}\end{array}\right\}{H}_V\left(i{\omega }_n\right)\exp \left(i{\omega }_{n}t\right)}\\ {\dot{d}}^{*}\left(t\right)=i{\displaystyle \sum _{n=-N}^N\left\{\begin{array}{c}{c}_{X,n}\\ c_{Y,n}\end{array}\right\}{H}_V\left(i{\omega }_n\right)\mathrm{sgn}\left({\omega }_n\right)\exp \left(i{\omega }_{n}t\right)}\end{array},$$

(A12)

The author apologizes for any inconvenience caused and state that the scientific conclusions are unaffected. The original publication has also been updated.