AIP Conference Proceedings [Author(s) HUMAN-DEDICATED SUSTAINABLE PRODUCT AND PROCESS DESIGN: MATERIALS, RESOURCES, AND ENERGY: Proceedings of the 4th International Conference on Engineering, Technology, and Industrial Application (ICETIA) 2017 - Surakarta, Indonesia (13–14 December 2017)] - Development of diagonal strut width formula for infill wall with reinforced opening in modeling seismic behavior of RC infilled frame structures