There have been several studies on analyses using finely meshed finite‐element (FE) models to understand in detail the behaviors of buildings during severe earthquakes. The accuracy of such analyses is often validated by comparing the results to the corresponding full‐scale shaking‐table test. While this approach is highly successful in terms of accuracy, no studies have considered the effect of fractures of members. In this study, numerical analyses are conducted for a steel structure subjected to multiple series of excitations in a full‐scale shaking‐table test considering fractures. The structure is modeled with planar and solid finite elements, and the fracture is treated by the mandatory deletion of elements at the time at which the fracture is observed in the experiment. The results show that by considering the fracture of steel members with the deletion of elements, the history of input excitations, and the resulting damages, the behaviors can be simulated analytically with a much higher accuracy.
Elastin-like peptides (ELPs) sequences are repeats of the pentapeptide GVGVP, and they have the ability to coaggregate reversibly, depending on the temperature. By exploiting this characteristic, a novel extracellular matrix protein (ECM) containing ELP was developed genetically to harvest a cell sheet from a culture dish. One of the ELP constructs, G288, consisted of 288 repeats of the sequence GVGVGP (G); it was attached to a hydrophobic dish surface. Next, cells with the sequence His-G36RG36, which has a His tag and an RGD sequence (R) that promotes attachment of the cell between the G36 sequences, consisted of 36 repeats of the sequence GVGVP, were added to the dish. After these cells became confluent, the temperature was changed to 20 degrees C in order to reverse the coaggregation. At this temperature, cells could be detached from the dish as a cell sheet. This genetically engineering method for construction of thermoresponsive ECM would be suitable to modify ECM with further functional domains.
In recent years, resonance in high‐rise buildings due to long‐period ground motion, which induces large‐amplitude cyclic deformation of seismic dampers, has become a matter of significant concern. Performance requirements for seismic dampers that are installed in vibration‐controlled buildings have become more stringent, and durability against cyclic deformation has become essential. An Fe‐15Mn‐4Si‐10Cr‐8Ni alloy with enhanced low‐cycle fatigue resistance has been developed to produce steel seismic dampers that are durable against large‐amplitude cyclic deformations. We used this alloy to develop two types of fatigue‐resistant seismic dampers (shear panel and brace‐type) that counteract long‐period ground motion. Furthermore, cyclic loading tests were conducted to validate the deformation performance and fatigue resistance of the developed damper. The results indicated that these dampers exhibit significantly better fatigue life than conventional steel dampers and exhibit outstanding deformation performance and durability under low‐cycle fatigue. The proposed two types of dampers were installed on steel structure buildings in Japan. These dampers ensured that the buildings with seismic performance margins can withstand long‐period and long‐duration ground motion and repeated after‐quakes.
There have been some researches on analysis using finely-meshed FE model to understand in detail the behaviors of buildings during severe earthquakes. The accuracy of such analysis is often validated by comparing the results to the corresponding full-scale shaking table test. While they are highly successful in the accuracy, no researches take account of the effect of fracture of members. In this paper, numerical analysis is conducted for a steel structure subjected to multiple series of excitations in a full-scale shaking table test considering the fracture. The structure is modeled with planar and solid finite elements and the fracture is treated by mandatory deletion of elements at time when fracture was observed in the experiment. It is shown that, by considering fracture of steel members with deletion of elements the history of input excitations and caused damages, the behaviors can be simulated by analysis with much higher accuracy.
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