Rangachar Narayana Iyengar also known as RNI (born 2 June 1943) is a civil engineer from India.
He was with the Indian Institute of Science, Bangalore for about four decades.
He has been the director of Central Building Research Institute, Roorkee (1994–2000).
He is currently a Raja Ramanna Fellow, Editor of 'SADHANA' published by the Indian Academy of Sciences, Bangalore, and the Director for the Center for Ancient History and Culture (CAHC) at the Jain University, Bangalore.
He also setup the Center for Disaster Mitigation (CDM) at the Jain University .
Apart from his contributions to Engineering, he is also widely recognized for his work in History of Science.
He is a fellow of Indian Academy of Sciences, Indian National Academy of Engineering and National Academy of Sciences, India.
He was awarded the Alexander von Humboldt Fellowship (Senior 1978-80, 1992 and 1997).
He is the recipient of the Sir M Visvesvaraya award (Government of Karnataka 1996) for senior scientists for lifetime contributions to science and technology.
He has held visiting positions at the Purdue University, Brooklyn Polytechnic, New York and Distinguished Schimdt Visiting Chair, Florida Atlantic University (1995).
He has led field investigations after the Khilari (1993), Chamoli (1999) and Kutch (2001) earthquakes.
He has been a consultant to various industries and research & development organizations in India including NPC, IGCAR, DRDO, RDSO, BHEL and Kerala State Government.