A new method is presented for predicting rolling element bearing condition from measurements of bearing housing vibration. This method is based on a statistical parameter Kurtosis, that remains constant for an undamaged bearing irrespective of load and speed, yet changes with damage. The extent of damage can be assessed from the distribution of this statistical parameter in selected frequency ranges. An assessment of bearing condition can thus be made with minimum recourse to historical information. Most other damage detection techniques rely heavily on the trend analysis of data and so this new method may prove to be a significant advance in bearing fault detection technology, at least when viewed within the original objective to provide a simple and cheap technique. As with most other simple detection techniques, the precise nature of the fault cannot be defined and for such information it is necessary to use the more sophisticated diagnostic methods.

This paper is concerned with the initial load–slip behaviour of laterally loaded bolted timber joints and deals specifically with verifying a theory for determining the values of slip modulus in mechanically fastened timber joints. Such a theory is essential in dealing with the phenomenon of interlayer slip, which occurs in built-up timber columns with nonrigid joints. The concept of a beam on an elastic foundation is used to evaluate the slip modulus. The theoretical predictions are compared with the test results of 75 timber joints. Good agreement is observed between the experiment and the theory. Key words: timber joints, bolts, nails, wood, interlayer slip, slip modulus, built-up wood columns, shear, lateral loads.

A rational procedure for determining the strength of spaced timber columns is presented. The effect of interlayer slip, characteristic of layered systems with nonrigid connections, is considered in the theoretical development. A good agreement is observed between the theoretical predictions and experimental results of some 110 spaced columns. The effect of number of spacer blocks on column strength is investigated, and efficiency of various types of spaced columns is compared, first with respect to each other and then with respect to equivalent solid and layered systems. Finally, the theory is compared with design specifications given by CSA Standard CAN3-086-M80, "Code for engineering design in wood." Key words: bolts, buckling, columns (supports), design practice, efficiency, nails, nonrigid connection, spaced columns, split ring connectors, strength, structural engineering, tests, theory, timber construction.

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