The architecture, Engineering and Construction (AEC) industry involve many disciplines during the life cycle of the building from its conception to its demolition. The civil engineering discipline has many domains related to AEC industry such domains include structural engineering, foundation engineering, construction engineering and materials. The structural engineering domain has many tasks that include modeling, analysis, design and detailing. The disciplines, domains and tasks of the AEC industry are related and often require data and information to be transferred electronically among them and/or across them. This paper presents an integrated Building Information Model (iBIM) for design of reinforced concrete structures. The proposed iBIM and its architecture have a framework similar to that of the Industry Foundation Classes (IFC) with its file-based data exchange standard and its central data base repository. The iBIM will facilitate integration of the structural engineering design tasks for reinforced concrete structures and will partially provide for interoperability among other related application programs. EXPRESS language and UML are used to define and represent the product and process models of the iBIM. A proof-of-concept prototype implementation of the tasks of the integrated structural engineering system that uses the proposed model and architecture was coded using Delphi object-oriented programming environment. An example of a beam object is shown to validate the proposed model. It is concluded that integration of other tasks of the structural engineering domain can be achieved using the proposed iBIM that made full utilization of the object-based modeling techniques and the IFC framework.