Scale models are becoming increasingly more important in research on structural concrete and are also being used quite widely in the design problem. Presenting a justification for the use of models in these areas the authors discuss the advantages and disadvantages of structural models in general.

The highly important question of accuracy of model results is explored in this paper. Before a decision is made to proceed with a model study the decision maker should be cognizant of the accuracy which can reasonably be expected in a model study, and once the decision to proceed is made, the model enigneer should know of the techniques and procedures which will lead to useful dependable results.

The use of model for studying the dynamic behavior of concrete structures is described. Particular reference is made to the use of random vibrations for simulating earthquake loads. Instances of applications in dams, piers, tanks and buildings are presented.

The authors discuss the economic factors governing the choice of model analysis for a preliminary feasibility study, as the sole basis of structural design, and as a supplementary method for verifying an approximate analysis.

The problem of providing suitable reinforcement in small scale direct models of reinforced concrete structures is examined in detail. Maximum attention is given to behavior in bond of several different types of reinforcing wire. Basic strength properties of the wires are also presented, along with recommendations on annealing processes required in producing reinforcement of the proper strength. The study is restricted to wire sizes of no more than about 1/6 in. diameter.