Lightly reinforced concrete members are widely used in practice. In spite of their widespread use, there has been very little research regarding the shear capacity of these members, especially continuous members and members with tapered webs such as joists. Limited research indicates that the shear capacity of lightly reinforced members is below that predicted by current design procedures. Thus, these structural components appear to have a lower margin of safety than other components of reinforced concrete structures. The current research will determine the shear strength of continuous, lightly reinforced T.beams and joists. Both single web and triple web members will be tested. The effects of flexural reinforcement ratio, degree of shear reinforcement, and load sharing between joists will be considered. The cracking shears will be compared with existing empirical and analytical expressions. The contribution of concrete, shear reinforcement, dowel action and aggregate interlock to shear strength will be estimated. Modifications to current design expressions will be developed. The research will fill a major gap in current understanding and allow the formulation of rational design provisions. The research will result in improved safety for an important class for reinforced concrete structural components.