Theoretical and experimental studies have been made of the effect of non-fracturing reinforcing members on the growth of a central crack in metal and polymeric sheets subjected to a uniform tensile load. The crack has been aligned perpendicularly to the reinforcing members which have been oriented in the same direction as the applied load. As a consequence of interactions between the non-fracturable and fracturable components of the composite structure, crack growth in the latter is inhibited severely. At the same time the non-fracturing reinforcing members provide a residual fail-safe load bearing capability. Tolerable agreement is observed between the predictions of the proposed theory and the observed behaviour of experimental samples.