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Due to their ability to provide more uniform story drifts with building height, strongback braced frames (SBFs) have been proposed as enhanced-performance structural systems. Conventional design approaches, however, tend to underestimate force demands in strongback elements compared to nonlinear response history analysis (NRHA). To address this gap, alternative methods such as modal pushover analysis (MPA) have been suggested to obtain less computationally intensive estimates of seismic demands. This study presents a statistical assessment of MPA as an estimate of NRHA force demands for an 8-story SBF subjected to 44 far-field ground motion records scaled at the risk-adjusted maximum considered earthquake (MCE𝑟 ) intensity level. Unlike prior studies that compare MPA results to the statistics of the NRHA response, this work treats each ground motion as a separate test to characterize how MPA accounts for record-specific spectral characteristics. Accuracy in estimates of the force demands (i.e., how close the MPA estimates are to the NRHA “truth”) is characterized using root mean square error. Additional comparisons are made across the MPA parameters, such as the number of modes employed, as well as the use of initial versus elongated periods. Results provide a comprehensive statistical assessment of MPA, illustrating that the approach can be sensitive to spectral assumptions and is better suited to aggregated estimates from NRHA. 

Concentration of drifts due to story mechanisms can lead to severe structural damage and economic loss. Frame-Spine systems have been proposed to mitigate these effects by redistributing drift demands with building height; however, systems can also exhibit near-elastic higher-mode effects, resulting in forces and floor accelerations that remain largely unreduced by inelastic behavior, thereby adversely affecting acceleration-sensitive nonstructural components and occupants. To address near-elastic higher-mode effects, Force-Limiting Connections (FLCs) have been introduced limiting force transfer between the frame and the spine and reducing acceleration demands through controlled yielding components. This study presents observations from full-scale shake-table testing of a four-story Frame-Spine and a Frame-Spine-FLC specimen at E-Defense. Results highlight higher-mode effects under strong shaking, with emphasis on (1) story shear resisted by the spine, (2) force–deformation behavior of the spine-to-frame connections, and (3) vertical distribution of forces. These findings provide experimental evidence of higher-mode participation in Frame-Spine systems and support the development of improved design guidance and controlling mechanisms. 

Even with strong-column-weak-beam design requirements, story mechanisms have been observed in Moment Resisting Frames (MRF), resulting in concentrated drift demands that can result in severe structural damage to drift-sensitive components. Frame-Spine systems can redistribute demands with building height, but near-elastic higher-mode effects tend to contribute to floor accelerations, affecting damage to acceleration-sensitive nonstructural components. To mitigate this tradeoff, Force-Limiting Connections (FLCs) have been proposed to reduce accelerations through yielding components between the Frame and Spine, thereby limiting the magnitude of the forces. This study examines the sizing and placement of FLCs in a four-story Frame-Spine system using stochastic simulations. The T-shape yielding element dimensions in the FLC were modeled as random variables at each floor, and Monte Carlo simulations were used to explore their effect on drifts and accelerations. Results show the dominant role of the first-story FLC on balancing drifts and accelerations, while upper-story devices offered limited benefit. Design recommendations are provided to constrain first-story yielding element dimensions within effective bounds that reduce peak accelerations relative to the baseline Frame-Spine configuration. 

Copper-mediated methodologies for the arylation of bis-azolium salts and bis-azoles are efficient pathways to access symmetrical and unsymmetrical N-heterocyclic carbene precursors. The arylation of bis-azolium salts with various aryl halides was achieved in moderate yields to furnish numerous C2-arylated bis-azolium salts. Access of C2-arylated bis-azolium salts from bis-azoles was also achieved in a single pot domino reaction via the use of iodonium salts as embedded electrophiles. The latter methodology utilizes the aryl iodide byproduct from the N-arylation step for the C–H activation step to mitigate waste and the need to recycle. We also demonstrated the use of these azolium salts in metalation and found success in obtaining metal complexes containing abnormal N-heterocyclic carbenes. 

Maternal trauma influences infant and adult health outcomes and may impact future generations through epigenetic modifications such as DNA methylation (DNAm). Research in humans on the intergenerational epigenetic transmission of trauma effects is limited. In this study, we assessed DNAm signatures of war-related violence by comparing germline, prenatal, and direct exposures to violence across three generations of Syrian refugees. We compared families in which a pregnant grandmother versus a pregnant mother was exposed to violence and included a control group with no exposure to war. We collected buccal swab samples and survey data from mothers and 1-2 children in each of 48 families (n = 131 participants). Based on an epigenome-wide association study (EWAS), we identified differentially methylated regions (DMPs): 14 were associated with germline and 21 with direct exposure to violence. Most DMPs showed the same directionality in DNAm change across germline, prenatal, and direct exposures, suggesting a common epigenetic response to violence. Additionally, we identified epigenetic age acceleration in association with prenatal exposure to violence in children, highlighting the critical period of in utero development. This is the first report of an intergenerational epigenetic signature of violence, which has important implications for understanding the inheritance of trauma.