Plastic design of steel bridge girders
1998 (English)Doctoral thesis, comprehensive summary (Other academic)
This thesis assesses the feasibility of a modified plastic design method for continuous steel or composite bridges with slender I-girders. The feasibility evaluation of the design method is closely connected to the moment-rotation relationship of the I-girders at internal supports. Due to local buckling of the slender I-girders, the full plastic moment resistance cannot be sustained as the rotation develops. On the contrary, the girders will reach a moment maximum, which might be less than the full plastic moment, followed by a decline in moment resistance as the rotation increases. Assuming that the moment-rotation relationships are known for all plastic hinges developing in the bridge, a plastic design method can in principle be employed but modified for these relationships. A fundamental condition for a modified plastic design method to be employed is thus that the moment-rotation relationships can be predicted. A simple plate model is developed in this thesis, which predicts the moment-rotation relationship for girders with compact or semi-compact flanges and slender webs. Included in this thesis is also test results in fourteen slender, high- strength steel girders in three point bending tests. A study on the lateral instability of I-girders and also an evaluation of the modified plastic design method with respect to the formal risk of failure, compared to an ordinary elastic design, have also been included.
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 1998. , 200 p.
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544 ; 1998:09
Research subject Steel Structures
IdentifiersURN: urn:nbn:se:ltu:diva-17777Local ID: 524eb5a0-8231-11db-aabe-000ea68e967bOAI: oai:DiVA.org:ltu-17777DiVA: diva2:990783
Godkänd; 1998; 20061123 (haneit)2016-09-292016-09-29Bibliographically approved