Behaviour and evaluation of pin-connected steel truss bridges

Abstract

Two posted bridges, with pin-connected steel trusses, were recently proof tested in Ontario. This paper presents some results of the tests and draws conclusions, which are also applicable to other similar structures. It is concluded that, unlike other bridge types, this type of bridge does not possess reserve strengths beyond those ascertained analytically. An experimental procedure is given in the paper using which the ratio of dead loads in the two components of a tension chord can be readily determined. This paper also describes a procedure by which equivalence between the test and design vehicles is established, thereby providing a basis for determination of the posting loads. Key words: bridge evaluation, bridge testing, pin-connected truss, posting load, proof test, through truss, steel truss, tension chord.