SUMMARY.

The report describes the results of a series of 36 tests on 400 mm deep by 200 mm wide prototype beams with no shear reinforcement, similar half-depth beams and 1:2, 1:3. 3 and 1:8. 5 scale model beams. The size of the aggregate was also scaled. The structural behavior, including cracking and ultimate strength, of the models and prototype is compared. The implications of the results obtained for the analysis of model tests are discussed and reasons for any scale effects observed are proposed. Finally, possible improvements in model techniques where shear is being considered are discussed.