The model has a span of 100cm and rise 25cm. Both ends are hinged but one of the ends is also free to move longitudinally. A lever arrangement is fitted at this end for the application of known horizontal inward force for measuring the horizontal thrust. Along the horizontal span of the arch various points are marked at equidistant for the application of load. This being a statically indeterminate structure of the first degree. A dial gauge with 25mm travel (with magnetic base) is supplied with the apparatus. Apparatus is supplied complete with a supporting stand and a set of weights.