Accelerated bridge construction reduces ill effects of traditional bridge construction techniques. To accelerate the bridge construction, several bridge systems have been developed utilizing precast concrete components. These bridge systems are constructed by assembling precast components together and joining them by posttension or any other means. Most of the bridge superstructure systems that are built with precast segments fall within the category of orthotropic bridge decks. The drawback of these bridge superstructure systems is the lack of design models. Current empirical design approaches fail to correctly address the load demand at the longitudinal joints of the orthotropic bridge superstructure systems. Failure of these joints compromises structural integrity as well as the bridge safety. Therefore, there is an eminent need of developing rational design models for orthotropic bridge superstructure systems. In order to develop rational design models there has to be analysis models of orthotropic bridge deck systems. This paper presents a procedure for developing macromechanical models of precast orthotropic bridge superstructure systems using the concept of macromechanicals and representative volume element in conjunction with the finite element method. Model development procedure is elaborated using a side-by-side box-beam bridge superstructure system. Macromechanical model presented in this article will later be used to develop rational design models of precast orthotropic bridge superstructure systems. Once the rational design models are developed to address the load demand at the joints of precast segments used in accelerated bridge construction, joints can be designed to avoid or abate cracking assuring integrity and safety of bridges.