Search

• Combining a flexible rocking wall system and the flexibility of timber can result in a building with considerable flexibility. • This paper investigates how the partition wall detailing affects the dynamic properties of the structural system. • This paper determines when it is beneficial to consider nonstructural walls in the overall building resistance. • Fixed partition walls contribute significantly to the overall seismic resistance while deformation-compatible ones offer little resistance. The structural-nonstructural interaction effects of nonstructural partition walls and post-tensioned CLT rocking walls in mass-timber buildings were evaluated in a parametric study. Representative 2D rocking wall units in 5-story and 12-story mass-timber archetype buildings were modeled in OpenSees. Moreover, concentrated spring models were developed to represent effective force-deformation for four different variations of partition wall detailing, and applied to the building models to represent wall densities associated with apartment and hospitality occupancies. Eigenvalue, pushover, and response-history analyses were performed on 2D models of the bare structure and those with partition wall variations. Including partition walls with fixed connection details was found to decrease story drifts and rocking wall story shears compared to the bare frame model by up to 50% in a service earthquake and up to 30% in a maximum considered earthquake. However, partition walls with deformation-compatible details were found to have negligible influence (less than 5%) on the response. [ABSTRACT FROM AUTHOR]

• The benchmark wall formed multiple flexural cracks for even curvature distribution. • Debonding of reinforcement helped to distribute strain and delay bar buckling. • An improved debonding detail is suggested for future evaluation. • Walls with advanced cementitious materials had increased crack propagation initially. • Walls with advanced cementitious materials fell short of expectations at large drifts. As a consequence of recent earthquakes in New Zealand, many concrete buildings have been demolished due to structural damage. Observations of damage to concrete walls led to substantial research and revisions to design standards to ensure that a satisfactory ductile response was achieved. However, even when the current performance objectives of the design standards are met, reinforced concrete walls may still require extensive or costly post-earthquake repairs. The objective of this project was to evaluate simple modifications to conventional reinforced concrete walls to increase their repairability. Four modified walls were constructed and subjected to cyclic lateral in-plane loading until failure, and compared to a previously tested conventional ductile reinforced concrete benchmark wall that failed at 2.5% drift. The modifications considered included debonding of reinforcement at the wall base, substituting fiber-reinforced concrete (FRC) for conventional concrete, and substituting engineered cementitious composite (ECC) for conventional concrete in the ends of the plastic hinge region (applied in two walls). Debonding delayed vertical reinforcement buckling, but failure occurred shortly thereafter (2.5% drift) due to constricted movement of the buckled bars within the debonding sleeves. The FRC and both ECC walls had increased crack propagation up to a drift demand of 0.5%, but then the cracks localized to a single dominant crack and the walls failed at drifts lower than the benchmark wall (about 1.5%). Modifications of the tested details are recommended for future test programs that investigate the repairability of concrete walls. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive design methodology for a magnetorheological-based damper device for a three-dimensional building isolation. The device acts as a suspension system itself by combining the liquid stiffness and controllable magnetorheological damping features in one unit. The bi-linear liquid stiffness feature enhances resistance to global rocking/overturning of the structural system by increasing the stiffness in the rebound mode compared to the compression mode. In the field, the system is combined with the conventional elastomeric bearings widely employed to mitigate the lateral seismic motions. During a seismic event, the system is subjected to dynamic vertical shaking and large lateral forces. The theoretical and simulation modeling to overcome this major challenge and achieve other system requirements are presented. In addition, a comprehensive optimization program is developed to achieve all design requirements. The modeling procedure is verified with experimental results. Also, the effectiveness of Displacement/Velocity-based control for a single degree-of-freedom system subjected to sinusoidal loading is evaluated. [ABSTRACT FROM AUTHOR]