Richard Stuart Henry

The combination of reinforced concrete walls and steel frames is popular for structural systems in high-rise buildings globally, and in New Zealand it has recently emerged as one of the most common configurations for low- and medium-rise construction. Bolted web plate connections in steel gravity load-resisting frames are usually assumed in design to act as a pin, even though they can generate significant moment resistance, and they must accommodate large inelastic rotations during seismic loading. In this study, four full-scale concrete wall–steel beam assemblages using bolted web plate connections were subjected to cyclic loading to quantify their expected seismic response and verify failure modes. Test variables included the presence of a floor slab with reinforcement projecting into the wall, the use of slotted holes, and the type of wall anchorage. After subjecting the connections to a constant gravity shear and cyclic rotation, all four test assemblages exhibited nonductile failure at moderate to high levels of rotation, characterized by concrete breakout. Although there was no loss of gravity load-carrying capacity, concrete breakout was considered a failure of the connection as tested. The rotation capacity of the connection was primarily influenced by bolt slippage, bolt hole elongation due to local yielding, and wall flexural deformation. The inclusion of the floor slab and continuity reinforcement increased the stiffness and strength of the connection and drastically reduced the connection rotation capacity. While adding slotted holes and using bent reinforcing bar anchors instead of headed studs improved the connection rotation capacity, these variations did not alter the ultimate failure mode.

Self‐centering wall (SCW) structures may generate floor acceleration demands substantially different from those of conventional reinforced concrete (RC) structures due to rocking‐induced higher‐mode amplification and nonlinear uplift–recontact behavior. This study investigates the floor response spectra (FRS) characteristics of SCW structures through combined experimental and numerical analyses and proposes a simplified generalized framework for engineering‐oriented FRS representation. Full‐scale shaking‐table test results demonstrated that resilient SCW systems develop more pronounced higher‐mode amplification and broader long‐period spectral plateaus than conventional RC structures under increasing seismic intensity while maintaining limited structural damage and stable self‐centering capability. The FRS of SCW structures exhibit characteristic bimodal spectral morphology consisting of a short‐period amplification region associated with higher‐order modal response and a long‐period plateau governed by the fundamental rocking mode. A validated nonlinear OpenSees model was subsequently used to investigate the influence of structural period, nonlinear rocking response, equivalent damping ratio, and gravity‐load distribution on FRS characteristics. Results indicate that modal properties and nonlinear rocking behavior dominate the spectral characteristics of SCW systems. Increasing seismic intensity progressively broadens the dominant spectral plateau and enhances short‐period amplification. Based on the generalized spectral characteristics identified from the numerical database, a simplified piecewise FRS representation framework was established using characteristic spectral breakpoints and representative spectral amplitudes. The proposed framework reasonably reproduces the dominant spectral morphology and spectral broadening trends observed in resilient SCW systems while substantially reducing the complexity of the original spectra.

Analyses of tall reinforced concrete (RC) shear walls subjected to earthquake excitation highlight the amplified dynamic moments that occur at the wall mid-height due to higher mode responses, as the cracking damages were observed at both base and upper region for tall RC shear walls in past shaking table tests. Such amplified moment demands may result in unexpected reinforcement yielding outside of the intended plastic hinge region and impact on the termination rules for longitudinal reinforcement contents within the upper portion of RC shear walls. The aim of this study was to investigate the dynamic response of tall RC shear walls designed with minimum longitudinal reinforcing contents. A fibre model scheme was developed and validated against prior test results to ensure accuracy in calculating the dynamic responses. Material regularisation techniques were adopted to ensure an objective calculation for both global and local response parameters. A series of parametric analyses were then conducted to investigate several key aspects of the dynamic response of lightly reinforced walls, including the impact of a high cracking moment, ground motion types, comparisons between dynamic and pushover responses, influence of high concrete tensile strengths, the reinforcement contents in the upper stories, and the magnitude of axial load. The analyses also investigated the curtailment height of longitudinal reinforcement for key design scenarios. The dynamic analyses conducted showed no evidence of highly concentrated strains in the upper portion of the walls modelled, resulting in a low risk of premature fracture of reinforcement in the upper stories of lightly reinforced tall walls. In addition, the longitudinal reinforcement termination requirements stipulated in the current design provisions were found insufficient to restrict the peak reinforcement strain within the detailed plastic hinge region. In order to prevent the unexpected inelastic failure with the peak reinforcement strains in the non-detailed upper region rather than at the detailed wall base, the revised longitudinal reinforcement termination rule was proposed for the regions above the plastic hinge to ensure satisfactory seismic performance.

In recent earthquakes, poor performance and collapse of buildings attributed to inelastic torsion responses have been reported. The torsional responses of buildings have been extensively studied with analytical models, but large‐scale experiments considering seismic‐induced torsion demands on buildings are rare. A shake‐table test of a two‐storey, low‐damage concrete wall building with strength asymmetry in the plan view was recently conducted, and the response of the building to both unidirectional and bi‐directional loadings at the design‐level earthquake intensity is presented. Analysis of the results includes the global responses of the structural components and the centre of mass for the test building, the strength response of unbonded post‐tensioned walls, the interaction between the translational strengths and torque, the total absorbed energy related to the torsional rotation, and variations in the eccentricities of the centres of rigidity and strength. Furthermore, the seismic response of the test building is explained with a comparison to previously published torsional mechanisms. Key outcomes from the analysis of the test results included: (1) an increase in the strength asymmetry and bi‐directional loading both amplifies the torsional rotations and effects the displacement and strength responses of the structural components along the perimeter of the diaphragm; (2) the comparison to previous torsional mechanisms shows a desirable level of agreement and supports the utilization of these mechanisms to assess the torsional performance of low‐damage wall buildings with irregularities; and (3) despite exhibiting a strong torsional response, the test building with the asymmetric strength configurations still achieved the low‐damage performance targets.

Purpose: Transgender-based discrimination is associated with poor mental health, unemployment, and poverty. Travestis and transgender women (trans women) frequently experience transgender-based discrimination, but associated factors are understudied. Our objective was to identify the factors associated with transgender-based discrimination among trans women from Brazil. Methods: We used data from Transcendendo, a clinic-based cohort of trans women in Rio de Janeiro, Brazil. Eligible participants were ≥18 years old, assigned male sex at birth, and self-identified as travestis , transgender women, or other trans feminine identities. We analyzed baseline data for participants enrolled from August 2015 to March 2020. Face-to-face questionnaires collected data on socio-demographics, gender identity and expression, and transgender-based discrimination experience. Factors associated with transgender-based discrimination were evaluated through multivariable linear regression. Results: Out of the 587 participants, 559 (95%) were included (28 excluded due to missing data). Mean age was 33 years, the majority identified as transgender women (40%), 71% reported current or past sex work, and 43% self-reported as living with HIV. In multivariable regression models, factors significantly associated with transgender-based discrimination included having no supporting or one supporting parental figure (vs. support from both parents), living in poverty (vs. not), and current and past sex work (vs. never). Conclusions: Trans women without family support, who engaged in sex work or were economically deprived were more prone to transgender-based discrimination. A lack of parental support, the strongest independent predictor of transgender-based discrimination experiences, likely contributes to emotional and structural vulnerabilities.

Past research that investigated the behaviour of rectangular lightly reinforced concrete walls resulted in revisions to minimum vertical reinforcement provisions in concrete design standards in both New Zealand (NZS 3101:2006) and the United States (ACI 318-19). However, the minimum vertical reinforcement provisions developed for rectangular wall sections may not be suitable for non-rectangular walls due to the influence of flanges on the nominal flexural and cracking section capacities. A parametric study confirmed that non-rectangular wall sections with minimum vertical reinforcement in accordance with current NZS 3101 design provisions exhibit a lower margin between cracking and nominal flexural strength than comparable rectangular wall sections. The ratio of the sectional nominal flexural strength to cracking strength (Mn/Mcr ) was less than 1.0 for non-rectangular sections with long flange lengths and low axial loads. The model results indicated that current vertical reinforcement requirements are insufficient to prevent a sudden and potentially unstable strength drop when cracking occurs in non-rectangular walls. A theoretical equation to calculate the required minimum vertical reinforcement was proposed for the typical I-shaped wall sections, including the impact of concrete strength and flange to web ratio. The proposed equation highlighted the need for an increase in the minimum vertical reinforcement limits for non-rectangular wall sections compared to the existing minimum vertical reinforcement requirement applicable to rectangular wall sections.