Effects of vehicle impact loading on masonry arch parapets

The vast majority of masonry arch bridges have masonry parapet wall supported on the spandrels. For bridges carrying roadways there is a potential risk of accidental vehicle impact from highway traffic. Such loads are typically of a short duration and the response of the masonry wall to such impact loading is an important safety consideration. This is of particular significance in the case of bridges over railways or highways, as falling masonry could have serious safety implications for the road or rail traffic below. An assessment of the risks requires an understanding of wall behaviour under such localised transient loading and an analytical approach for predicting the wall response. This paper briefly summarises an experimental programme on masonry walls using a specially designed impact loading rig which reproduces the forms of force/time history developed during a motor vehicle impact. The development of a dynamic, mechanism based analytical approach is discussed. (A) For the covering abstract, see IRRD E100543.