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Study on Behavior of Diagonally Stiffened Steel Plate Shear Walls

Akhavan Sigariyazd, Mohammad Hossein | 2016

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 48747 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Joghataie, Abdolreza; Khajeh Ahmad Attari, Nader
  7. Abstract:
  8. In this study, the behavior of diagonally stiffened steel plate shear wall systems which have a new configuration of stiffeners is investigated. This dissertation is divided into three main sections which contain experimental studies, finite element analysis and developing design equations. In the section on experimental studies, 5 single-bay, single-story, one-third scale specimens were tested. An unstiffened specimen as a control sample and two other specimens with different configuration of stiffeners were constructed and tested to study the effect of diagonal stiffeners. Based on the observations during the tests, it was decided to add and study two other specimens too, including one with a different columns-base connection to the bottom beam and one by replacing the I-shaped columns with box-shaped. Built-up sections were used and cyclic loading was applied using hydraulic jacks installed at the top beam level of the specimens. Using strain and displacement gauges, the behavior of each specimen was recorded during the loading. The results of the conducted experimental studies showed that the stiffened specimens dissipated less amount of energy compared to the control specimen; also it was observed that the specimen with box-shaped columns dissipated more energy compared to the specimen with I-shaped column. As was expected, the stiffness and lateral strength of the stiffened specimens were higher than the control specimen. Quantitatively, the stiffness and ultimate strength of the control specimen was 28 and 7 percent less than the average values for the stiffened specimens, respectively. Between the stiffened specimens, the specimen which contains non-intersecting stiffeners, which reduces the heat stresses on the web plate, showed higher stiffness and strength. For the specimen with box-shaped columns, the stiffness was very similar to the specimen with I-shaped columns but its ultimate strength was 19 percent higher. From the perspective of earthquake engineering, the ductility, overstrength and response modification factors were calculated as 4.5, 2.0 and 5.7, respectively for the stiffened specimens and 8.0, 1.8 and 7.0 for the unstiffened one, respectively. These results show that the stiffeners had reduced the ductility of the system. Also it was concluded that the calculated values for the stiffened and unstiffened specimens regarding the portion of shear resisted by the web plate are less than the proposed values by the code. However, it should be noted that the obtained results are for the case where gravity load has not been considered in this study. In the finite element analysis section, after verifying the models considering the out of planeness of the web plate and size of the mesh, the calculated values for stiffness and strength were compared to experimental results which revealed the accuracy of the finite element analysis. Furthermore the stress concentration zones for each specimen were very similar to what observed in the lab. Also, in this section the effect of the presence of the web plate on improving the structural behavior of the system such as stiffness and strength was studied by eliminating the web plate from the control system. In the section for developing design equations, assuming superposition rule would hold, an equation was derived for estimating the capacity of steel plate shear wall systems with and without diagonal stiffeners. This equation was derived by summing up the shear force resisted by the web plate, tensile and compressive diagonal stiffeners and the surrounding frame. The shear capacity calculated by the equation well matches the shear capacity observed in the lab
  9. Keywords:
  10. Steel Plate Shear Wall (SPSW) ; Diagonal Stiffener ; Seismic Behavior ; Seismic Behavior ; Experimental Studies ; Finite Element Method ; Ductility

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