Effects Of Column Splice Properties On Seismic Demands In Steel Moment Frames

Dynamic inelastic response history analysis of a 2-D model of a nine storey steel frame were carried out with different column splice strengths and stiffnesses using a suite of 20 MCE level earthquake records. Splices were located every 2nd storey at one third of the storey height up from the column below. It was shown that (i) the presence of even very flexible splices increased the frame period by less than 3%, (ii) flexible splices increased storey drift ratios by up to 27%, (iii) splice stiffnesses of zero to infinity had no effect on frame displacements, (iv) the splice moment demand increased with increasing splice stiffness on the frame and was as high as 99% of the column flexural capacity

Critical excitation-rate enhancement of a dipolar scatterer close to a plasmonic nanosphere and importance of multipolar self-coupling

We develop an electrodynamic model based on dyadic Green's functions for analyzing the near-field interactions between a dipolar scatterer (DS) and a plasmonic nanosphere (PN) under external excitation, accounting for multipolar contributions in the evaluation of the scattered fields. In particular, we include all the radiative and nonradiative field interactions between the DS and the PN, particularly the physical mechanism of DS's self-coupling through the PN, which is either neglected or approximated in previous work. Our objective is to show under which conditions self-coupling is important for strong excitation-rate enhancement of the DS and provide a description of the system's properties. We analytically investigate the conditions under which the excitation rate of a DS, such as an organic dye or a quantum dot, is enhanced when located in close proximity to a PN. We show the existence of critical conditions in terms of polarizabilities and distances that lead to large enhancement based on self-coupling and how to predict it

Bending Stiffness and Strength Performance of Different Column Splice Connections

Tall steel structures are increasingly common in seismic zones, but their column design relies on splice connections to create tall structures. Bolted splice connections may exhibit greater flexibility during strong earthquake shaking than expected by design. Although the strength characteristics of these connections are defined in guidelines and (some) standards (NZS3404), their stiffness and ductility characteristics are less known. In particular, the moment-rotation performance of column splices significantly affects the seismic response and possibility of an undesirable local or global failure. A series of moment tests were conducted on bolted and welded, bearing column splices across standard, universal column sections (310UC158, 310UC118) tested to failure. In particular, 3 bolted lap splice connections, 1 bolted end plate connection, and 1 welded splice connection. Specimens were quasi-statically tested in a Dartec machine. Flexural performance was assessed using moment-rotation hysteresis loop measurements at the splice to assess strength, stiffness and ductility. The welded splice was the most rigid and strongest, exceeding guidelines. The end plate splice was stronger than existing guidelines expect, and less ductile than the lap splices, which were the most ductile. Lap splice strength also exceeded guideline expectations. Splice connections consistently exceed guideline expected strength and have widely varying stiffness

Critical excitation-rate enhancement of a dipolar scatterer close to a plasmonic nanosphere and importance of multipolar self-coupling

We develop an electrodynamic model based on dyadic Green's functions for analyzing the near-field interactions between a dipolar scatterer (DS) and a plasmonic nanosphere (PN) under external excitation, accounting for multipolar contributions in the evaluation of the scattered fields. In particular, we include all the radiative and nonradiative field interactions between the DS and the PN, particularly the physical mechanism of DS's self-coupling through the PN, which is either neglected or approximated in previous work. Our objective is to show under which conditions self-coupling is important for strong excitation-rate enhancement of the DS and provide a description of the system's properties. We analytically investigate the conditions under which the excitation rate of a DS, such as an organic dye or a quantum dot, is enhanced when located in close proximity to a PN. We show the existence of critical conditions in terms of polarizabilities and distances that lead to large enhancement based on self-coupling and how to predict it

Critical excitation-rate enhancement of a dipolar scatterer close to a plasmonic nanosphere and importance of multipolar self-coupling

We develop an electrodynamic model based on dyadic Green's functions for analyzing the near-field interactions between a dipolar scatterer (DS) and a plasmonic nanosphere (PN) under external excitation, accounting for multipolar contributions in the evaluation of the scattered fields. In particular, we include all the radiative and nonradiative field interactions between the DS and the PN, particularly the physical mechanism of DS's self-coupling through the PN, which is either neglected or approximated in previous work. Our objective is to show under which conditions self-coupling is important for strong excitation-rate enhancement of the DS and provide a description of the system's properties. We analytically investigate the conditions under which the excitation rate of a DS, such as an organic dye or a quantum dot, is enhanced when located in close proximity to a PN. We show the existence of critical conditions in terms of polarizabilities and distances that lead to large enhancement based on self-coupling and how to predict it