Abstract: Deviations in flatness on a horizontal surface are measured by running over the surface, at a constant driven speed, an instrument sensitive to slope and which generates a continuous voltage signal corresponding to a continuous slope measurement. The continuous voltage signal is filtered to remove extraneous high frequency voltage signals thereby to produce raw continuous analog slope data which is digitized and calibrated to provide calibrated digital slope data from which other flatness data is computed. Procedures are described for calibrating the instrument and for eliminating or compensating for distortions in the measurements.

Abstract: Improved connections of preformed concrete construction elements wherein one or more metal pins, of any preferred cross-sectional shape, are cast in place, or grouted, extending into each of two elements to be connected, with an elastic grommet disposed between a portion of each pin, in an area on each pin nearest the joint, and the surrounding concrete or grout, whereby the load transfer capacity of the connection is increased about threefold.