12 C O N T E X T 1 1 0 : J U LY 2 0 0 9 recommendations are made to parochial church councils (PCCs), and subsequently to the diocesan advisory committee for the care of churches (the DAC), that a new steel or cast iron bell-frame should be installed. In these cases the old frame is either left in a redundant state, with no incentive for maintenance or protection, or it is discarded. It may even be consigned to the bonfire. When the recommendations for a new frame are made, there is also generally a recommendation that new frames are set at a lower level in the tower to reduce overall tower movement. This suggestion of lowering bell-frames in towers is not new. Ranald Clouston, a veteran and perhaps one of the most knowledgeable bell advisers ever, would inevitably suggest that it would be better if the bell-frames were lower. However, he accepted a sensible engineer’s view that it was not a disaster to leave them at their existing level, if the tower was repaired, which it would need to be even in the case of lowering the bells. Recently, a very well-known bell-frame was repaired and stabilised to a standard which was acceptable to bell-ringers generally, but the more outspoken ringers are recommending to the church that a new bell-frame should be put into the tower – at great cost. The Morton Partnership, when giving advice to PCCs or the DAC, has been responsible for guiding our clients as to whether, and how, these ancient bell-frames can be repaired. As engineers we have a significant difficulty in accepting the replacement approach, except in extreme cases. An argument put forward in support of replacing bell-frames is the suggested problem of tower sway, and potential damage to the structure. My experience of dealing with vibration and damage to structures over the past 40 years culminated in a report advising that damage to structures is not initiated by vibration movement. Certainly, if damage to a church tower does exist, where cracks have appeared over the centuries for all sorts of reasons, vibration can cause further problems. These cracks need to be repaired to ensure that the structural stability of the tower is retained when the bells are rung.This generally means tying across cracks to ensure that the tower acts as one unit, with one natural frequency. This also prevents dust vibrating into existing cracks and progressively jacking them open. This tower repair work would be necessary even if a new bell-frame were provided at lower level. Church towers do move, but experience and measurements suggest that for high towers, wind movements can be as great as the tower sway which occurs when bells are rung. We must remember that there is considerable flexibility in an historic church tower constructed with lime mortar. We have also managed to carry out effective repairs to historic bell-frames, both to deal with localised areas of decay, and to compensate for movement relating to the gradual loosening of joints caused by the large dynamic loading when the bells are rung. It has been found that in some bell installations all that is necessary is to replace the bearings and carry out localised repairs to the frame. If we continue going down the path of replacing historically important bell-frames with new frames, we will not only lose the important historic material, but we could also change the sound of bells ringing outside the tower significantly, due to the bells having been lowered. Bell-ringers have told us that one of the joys of bell-ringing is that bells are different to ring at each tower. Bell-frames are unique for their age. In some cases you could describe them as 400-year-old timber machines. They are not simply structures, but working devices that should be recognised as such and protected, being without compare. Brian Morton is a consultant to the Morton Partnership, the practice he formed in 1966. A restored timber bell-frame with new bearings
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