Extreme events over the past decade in the USA, ranging from the 9/11 terror attacks to the 2003 Northeast power blackout to the 2005 hurricanes, have highlighted the urgent need to understand the interdependencies among civil infrastructure systems for more effective and efficient planning, design and operations. The need is further highlighted by the challenges arising from the capacity needs of rapid urbanization and the need to renew aging infrastructure. This paper proposes a generalized modeling framework that combines a multilayer network concept with a market-based economic approach to capture the interdependencies among various infrastructure systems with disparate physical and operational characteristics. Thereby, the various infrastructure systems are modeled as individual networks connected through links representing market interactions. The market interactions capture the various types of interdependencies through supply-demand mechanisms. The modeling framework uses a multilayer infrastructure network (MIN) concept, the computable general equilibrium (CGE) theory, and its spatial extension (SCGE), to formulate an equilibrium problem. The mapping between the modeling framework and the real-world context is discussed, followed by a description of the various model components. Numerical experiments are conducted to illustrate the capability of the model to capture various types of interdependencies and to provide insights on the importance of these interdependencies for real-world problems.