On the Design of Large Elevator Platforms

Large elevator platforms are, in effect, complex systems of a comparatively few main framing members, coupled by a large number of stringers which support the flooring. As set forth in the paper, and as is qualitatively well known, a load placed on one of the main members is not carried by that member alone. Deflections, impressed by the loaded member on the stringers, induce forces which cause neighboring members to share in the support of the load. However, means to evaluate the distribution of the load with reasonable accuracy, important as it is for a rational design of the platform with the lightest structural shapes, hitherto have not been available. To furnish these is the purpose of the paper. With the aid of two assumptions, and the introduction of certain auxiliary forces, the problem is quickly reduced to the case of a beam, subject to a force at an arbitrary point, supported at its ends, and resting on a flexible foundation.