The concept of awareness was introduced to underline the importance of shared knowledge and enhance collaborative work. Actors require much knowledge about their work situation and their collaborators' activities in order to complete their own activities successfully. This paper first contributes to a detailed literature review about the concept of awareness. This review helps to identify key awareness-related requirements for the development of collaborative systems. The second contribution is related to the proposal of a generic situation model that is based on the concept of entities, interactions and specific roles. This new conceptual framework intends to favor situation awareness and support shared representations. It concerns both technical and organizational design activities and describes the collaborative situations from multiple views and at different organizational levels (project, team and individual). The proposal's interest and its feasibility for use in the development of collaborative systems are demonstrated by instances related to a case study and by analyzing the potential satisfaction of the identified awareness-related requirements. To sum up, the paper offers a synthesis of key context-related concepts and a generic model for the representation of collaborative situations to increase awareness.