Developing a testing protocol for new rivets in a rehabilitated metal bridge
Historic Preservation/Cultural Resources
Rehabilitation of historic metal truss bridges often involves the replacement of rivets in the original bridge. Insofar as the rivets are considered part of the historic fabric of the bridge, replacement of too many rivets with bolts may lead to an adverse effect. Resistance to replacing rivets with rivets largely comes from two quarters: 1) riveting is not a widely held skill and finding competent riveters is an issue; 2) more importantly, bridge engineers prefer round-head bolts over rivets because of the predictability in performance over time and set protocol for installation. The purpose of this study is to establish what are the strength parameters of rivets and to develop a practical test to determine the strength characteristics of new rivets. Given the historic performance of rivets as good for most existing bridges, it should be possible to demonstrate rivets as a suitable alternative to bolts. This may require materials testing both in the lab and field.
Replacement of rivets with round head bolts is appropriate in the rehabilitation of historic metal bridges, but wholesale replacement of rivets with bolts can at a point lead to an adverse effect, particularly when the rivets are a character-defining feature of the historic bridge. Replacing rivets with rivets appears to be a reasonable solution; however, bridge engineers need to be assured that the new rivets will perform to structural standards and not leave the bridge vulnerable to failure. Without this test and performance information on current riveting practice, new rivets will continue to be opposed by the structural engineering community.
May 8, 2017
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