Seismic-resistant truss moment frames with ductile Vierendeel segment.

Special Truss Moment Frame (STMF) is a structural system in which during a severe earthquake all inelastic deformations are confined in a portion of the truss girders called the special (ductile) segment. In an earlier study by Itani and Goel, STMF was studied for an X-diagonal configuration of the special segment web members. When using this configuration of the special segment the available space may be somewhat restrictive. In this study, a Vierendeel panel is proposed as an alternative configuration of the special segment. The proposed configuration allows greater flexibility and architectural freedom. An integrated analytical and experimental program is carried on full scale subassemblages of STMF with the proposed configuration. The first part of the dissertation deals with the experimental program carried out on the three full scale subassemblages. The test subassemblages include parameters such as length and location of the special segment, width-to-thickness ratio of angles in chords of the special segment, as well as different load combinations and loading sequences. Observations from the tests as well as analyses of the results are discussed. Design recommendations and guidelines for hand-calculation of forces in various members of the system are also presented. The second part of the dissertation deals with the analyses of test subassemblages and refinements in the design procedure. The moment-rotation bi-linear model generally used in analysis of beam-column elements was found inadequate for chords of the special segment. The model is modified for better agreement between analysis results and those of the tests. A rational expression for determining the required overstrength factor is also developed. The overstrength factor is used to ensure elastic behavior of members outside the special segment under fully yielded and strain hardened chords of the special segment. The remaining portion of the dissertation deals with dynamic analysis of the system under a severe earthquake record (Miyagi-Ken-Oki scaled to 0.4g). An exterior four-story frame of the study building in the long direction is designed and analyzed based on the refinements and modifications presented earlier. The frame showed excellent responses when compared to other framing systems under the same earthquake record.PhDCivil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/104255/1/9513297.pdfDescription of 9513297.pdf : Restricted to UM users only