National Science Foundation (NSF) support for operations of the current George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) ends on September 30, 2014, when the five-year NSF cooperative agreement with Purdue University for NEES operations expires. Under the separate program solicitation NSF 13-537, entitled "George E. Brown, Jr. Network for Earthquake Engineering Simulation Operations FY 2015-FY2019 (NEES2 Ops)," NSF is soliciting proposals to configure and operate the "second generation" of NEES infrastructure, hereinafter referred to in this solicitation as "NEES2." The competed infrastructure includes the management office, experimental facilities, cyberinfrastructure, and education and community outreach. As the outcome of that competition, the intent is to award one cooperative agreement to a lead institution for NEES2 operations with an award start date of October 1, 2014, and a duration of up to five years.To provide continuity in earthquake engineering research during the NEES2 competition period, NSF's Division of Civil, Mechanical and Manufacturing Innovation (CMMI) in the Directorate for Engineering (ENG) solicits proposals through this program solicitation for planning grants for research that could eventually require the advanced experimental capabilities of NEES2 facilities for follow-on research. Information about the NEES2 infrastructure will not be available until NSF issues the award for NEES2 operations. As the design of experiments in the follow-on research would be dependent on the specific NEES2 experimental facility to be used, NSF's expectation is that all preliminary testing at other than NEES2 facilities and preliminary numerical studies for proof-of-concept would have been completed under the planning grant, and researchers thus would be "NEES2-ready" to submit proposals in early FY 2015 to design experiments to directly utilize NEES2. Planning grant awardees are required to archive all experimental data generated during the research in the NEES2 operations awardee's data repository.