Seismic design of steel beam-to-column joints with reduced beam section using European hotrolled
The design rules on Reduced Beam Sections (RBS) are covered in the Eurocodes in EN1998-3 as a possible solution to improve rotation capacity of beams for the retrofit of existing structures. The design rules are very similar to those in AISC358 provisions, although European cross-sections and steel...
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| Format: | doctoral thesis |
| Status: | Published version |
| Publication Date: | 2021 |
| Country: | España |
| Institution: | CBUC, CESCA |
| Repository: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/673353 |
| Online Access: | http://hdl.handle.net/10803/673353 https://dx.doi.org/10.5821/dissertation-2117-361627 |
| Access Level: | Open access |
| Keyword: | Àrees temàtiques de la UPC::Enginyeria civil 624 69 |
| Summary: | The design rules on Reduced Beam Sections (RBS) are covered in the Eurocodes in EN1998-3 as a possible solution to improve rotation capacity of beams for the retrofit of existing structures. The design rules are very similar to those in AISC358 provisions, although European cross-sections and steel grades are different. Research pieces on RBS in a European environment are few and do not study this matter with an extensive parametric study to assess their behaviour. Moreover, the design rules in EN1998-3 only show how to design the weakened section of the beam, but they do not provide any additional information on whether further action is needed on the structure for the design of other members such as braces or if special considerations need to be made for connection detailing. The current state of the Eurocodes does not consider the design of a new structure with RBS, while AISC358 provisions do allow for new RBS designs. The aim of this PhD thesis is to study the behaviour of the RBS and find the most relevant design parameters affecting its response in a beam-to-column assembly level and to study the benefits of incorporating RBS as a solution for the design of new structures in seismic areas. In order to fulfill the first goal, a numerical model has been developed in Abaqus in order to assess the behaviour of RBS and to discuss the results obtained from them. Hot-rolled European sections have been studied from the HEA and IPE cross-section families, as well as a built-up slender girder and an American Jumbo section. Several different cutouts (or trimmed flange widths) are investigated, as well as S235 and S355 steel grades with their cyclic hardening properties. The influence on the column web panel strength is also considered in the parametric study. The results obtained are then examined to compare degradation ratios, overstrength ratios, lateral-torsional buckling development, dissipated plastic work and plastic damage by means of equivalent plastic strains (PEEQ). In order to fulfill the second goal, two different studies have been performed to assess the influence of the RBS in a structure subjected to seismic load. The behaviour of a structure provided with RBS is compared to that of a control structure without RBS. The results have been obtained and the differences found have been quantified in order to objectively report the benefits found when adopting RBS After having studied the behaviour of the RBS both locally (at a beam-to-column level) and globally, the main conclusions have been derived. Also, design recommendations to take into consideration for the design of new RBS are provided in order to ensure a proper behaviour of the RBS when subjected to seismic loads and to guarantee overall good structural behaviour. |
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