D.C. Code § 38-2021.18

The provisions of this part shall constitute a defined benefit plan and a governmental plan, as described in section 414(d) of the Internal Revenue Code , which is intended to qualify under section 401(a) of the Internal Revenue Code . Notwithstanding anything to the contrary contained in this part, Chapter 7 of Title 1 (§ 1-701 et seq.), or Chapter 9 of Title 1 (§ 1-901.01 et seq.), the provisions of this part shall apply to and control the provision of any annuity payable. The provisions of this part shall apply to all teachers on the rolls of the public schools of the District who accrue service after June 30, 1997, under the Teachers’ Retirement Program established pursuant to Chapter 9 of Title 1 (§ 1-901.01 et seq.), if otherwise eligible.