Inchinnan Opening Bridge

l. From the standpoint of purely theoretical design all the members in a framed structure should be made of such dimensions that their material will be stressed to the allowable limit under the external load system considered, since a structure proportioned in this way will ensure maximum economy in the use of material. In many cases such an ideal structure may be impracticable, and will have to be modified to meet a variety of conditions imposed byconsiderations other than those of theoretical design. Whatever modifications are necessary, however, to meet such conditions the ideal design will have considerable value as a basis for the development of the final scheme embodying the requirements of practical engineering. In some cases, e.g., in the design of all aircraft structures, the reduction of weight is such an important consideration that very little is permitted to stand in the way of its attainment, and in such cases this ideal structure would be very closely followed. Professor A.J. Sutton Pippard

The subject of this paper is the strength of rectangular slabs, but it is limited to such slabs as have an appreciable thickness coinpared with the span, and more particularly it is limited to slabs of reinforced concrete only. A. Ingerslev

In calculating the strength of plated rolled or built up sections it is usual first to calculate the moment of inertia about the neutral axis and then divide by the distance of the neutral axis from the extreme fibre. W.A. Green