Development of in situ joints for pre-cast bridge deck units

This paper, which extends research described in a previous paper, describes and discusses tests carried out to develop in situ joints suitable for pre-cast reinforced concrete deck units, for the decks of steel concrete composite bridges, in negative moment areas. The results of 18 tests of symmetric and non-symmetric arrangements of straight and looped bars are given together with comparisons to the theoretical strengths. The behaviour of the joints at serviceability and ultimate loads and beyond, are discussed. The tests show that the failure loads of joints containing looped bars can be accurately predicted based on the ultimate strength of the reinforcement provided there are adequate transverse lacer bars. Crack widths were measured in a number of specimens and it was concluded that they would be unlikely to impose a limitation at the serviceability limit state.