To address the challenges of sustainable management and development of the built environment, engineers and facility managers need to exploit the 3D City models which grown in recent years to include interior space. A crucial issue for facilitating interaction with these 3D city models is the ability to integrate 3D BIM into the geospatial context. This requires the use of specialized software and specific expertise. In order to simplify this process, we here propose an information system that facilitates the use of BIM for geo-analysis purposes. BIM4GeoA is a concept for combining existing open source software and open specification for efficient data management and analysis of Building Information within its boarder context. The core components are the spatial database PostgreSQL/PostGIS, the building information server, the industrial foundation class (IFC), the Google Earth 3D viewer, and the existing 3D OGC standard (KML, CityGML). This paper presents the procedure used to enable the development of this new expert system as applied to the context of 3D Web GIS. A thorough analysis of the strength and weakness of these different components has been undertaken to employ it is strength and override its weakness. The system architecture is operationally used in developing different applications for the management of a university campus; a large potential is provided for operational tasks of facility management department, such as utilities infrastructure, as well as public community (student, staff) like routing application, searching for a person with defined criteria.