AN ANALYTICAL RESPONSE OF CHURCH BELLS TO EARTHQUAKE EXCITATION

Occasionally there is an earthquake in the UK during which church bells are reported to have been set ringing. The motion of a medium sized church bell has been simulated and the response to earthquake records from the Parkfield earthquake of 1966 has been calculated. The response of the bells is found to depend on the mechanical properties of the bell and the tower in which it is hung. The analyses do show that for a bell to ring in an earthquake the peak ground acceleration is in the range 0.97 to 29.4 m s^?2 considerably in excess of the range indicated by the MMI VI “church and school bells ring” of 0.4 to 1.5 m s^?2. The best correlation between recognised earthquake parameters and the ringing of the bell was obtained by combining the spectral values for clapper-bell angle, obtained from the linearised set of equations, at the bells natural frequencies using the SRSS method. The values of this parameter to set the bell ringing was in the range 0.25 and 0.38 rad, compared with the actual striking angle 0.54 rad.     

FACTORS AFFECTING RESPONSE TO NOISE IN OUTDOOR RECREATIONAL ENVIRONMENTS

As the world gets more and more crowded, silence becomes a rarer and rarer natural resource. (Rennicke 1987, 27)     

CALCULATING THE COST OF TRANSFERRING STUDENTS FROM PAROCHIAL TO PUBLIC SCHOOLS: AN EXAMINATION AND CRITIQUE

Public sector aid to K-12 parochial schools is often justified on the basis that providing assistance is cheaper than having to absorb all those students into public school systems. But is it? The cost of transferring students from parochial to public K-12 schools has never been satisfactorily calculated. This article points to the weaknesses in previous efforts and outlines the elements that must be present in a comprehensive estimate of transfer costs.     

THE USE OF SIMPLE PULSES TO ESTIMATE INELASTIC RESPONSE SPECTRA

Inelastic response spectra are estimated for elasto-plastic SDOF systems subjected to strong earthquake ground motions by applying the strength reduction factors determined for a simple pulse to the elastic response spectrum of the ground motion. This approach relies upon similarities in the strength reduction factors computed for earthquake ground motions and for short duration pulses. The accuracy of the estimated inelastic spectra obtained using 24 simple pulse waveforms is assessed in order to identify subsets of just several pulse waveforms that are suited for this purpose. Based upon the ground motions and pulses investigated, this approach appears to be equally applicable to short and long duration ground motions and those having near-fault forward directivity features.     

THE ORCHARD INDUSTRY'S RESPONSE TO LOW-TEMPERATURE INJURY IN THE OKANAGAN VALLEY

Low-temperature injury in both winter and spring has been a problem for the Okanagan orchard industry since its beginning. The nature and history of low-temperature injury are described, and the response of the orchard industry is assessed. Three types of coping mechanisms are discussed: modifying the hazard, modifying the loss potential, and adjusting to the loss. Although or chardists are aware of the low-temperature hazard, they do not feel strongly threatened by it and believe that they have modified the hazard and loss potential to a point where they can, with institutional assistance, adjust to the level of losses they experience.