The 5 th World Construction Symposium 2016: Greening Environment, Eco Innovations & Entrepreneurship 29-31 July 2016, Colombo, Sri Lanka 1 I NTERACTIONAL A NALYSIS F OR T WO -P ARTY R ISK A SSESSMENT I N P UBLIC P RIVATE P ARTNERSHIPS (PPP) Rana Khallaf* and Nader Naderpajouh Lyles School of Civil Engineering, Purdue University Makarand Hastak Lyles School of Civil Engineering, Purdue University * Corresponding Author: E-mail-rkhallaf@purdue.edu, Tel-765-714-8353