The present work studies the combined in-plane (IP) and out-of-plane (OOP) collapse of unreinforced masonry infills (MIs) of strategic infrastructures such as hospitals retrofitted by hysteretic damped braces (HYDBs), where immediate occupancy (IO) and structural safety (SS, e.g. life-safety or collapse prevention) are the performance levels required after low-to-high amplitude earthquakes. Despite many advances in the development of new supplementary energy dissipation systems, few investigations have evaluated their effectiveness in improving the IP-OOP response of MIs. Because of the complex articulation of medical centres, reference is made to a five-storey pavilion of the hospital campus of Avellino in Campania (Italy). Bare and infilled structural models of this reinforced concrete pavilion are designed in a medium-risk seismic zone, in order to fulfill the corresponding IP drift ratio thresholds provided by a former Italian code for limiting nonstructural damage of MIs at the serviceability limit state. The IO and SS performance levels are checked in a displacement-based design procedure of the HYDBs at the Serviceability (SDE) and Basic (BDE) Design Earthquakes. An optimization procedure is considered, taking into account that an anticipated (delayed) activation of the yielding devices may give rise to concerns about their suitability with respect to high (low) intensity seismic loads. The demolition and reconstruction of MIs, which generally goes hand in hand with the introduction of damped braces in existing frames, is avoided. To this end, exterior, with diagonal damped braces in the window bays, and interior, with less-intrusive chrevron damped braces, retrofitting systems are adopted. Two aspect ratios of MIs are analysed assuming corner arrangements along the perimeter. Nonlinear time-history analyses for the four reference seismic levels assumed in the current Italian code highlight that IP and OOP failures of MIs can be avoided when the activation of the HYDBs at the SDE can be attained without jeopardising structural safety at the Maximum Considered Earthquake (MCE).

本工作研究了战略基础设施（如医院，由滞后阻尼支架（HYDB）改造的医院）的未加固砌体填充物（MI）的面内（IP）和面外（OOP）塌陷，其中即时占用（IO）结构安全性（SS，例如生命安全或防倒塌）是低至高振幅地震后所需的性能水平。尽管在开发新的辅助耗能系统方面取得了许多进展，但很少有研究评估其在改善MI的IP-OOP响应方面的有效性。由于医疗中心的错综复杂，因此请参考位于意大利坎帕尼亚的Avellino医院校园的五层楼阁楼。该钢筋混凝土亭子的裸露和填充结构模型是在中等风险地震带中设计的，为了满足相应的IP漂移率阈值，该阈值由以前的意大利法规提供，用于在可使用性极限状态下限制MI的非结构性损坏。在可维护性（SDE）和基本（BDE）设计地震中，在HYDB的基于位移的设计过程中检查IO和SS性能级别。考虑到优化程序，要考虑到屈服装置的预期（延迟）激活可能引起人们对它们对高（低）强度地震载荷的适用性的担忧。避免了通常在现有框架中引入阻尼支架的MI拆卸和重建。为此，在外部，在窗台中带有对角阻尼支撑，而在内部，则采用侵入性较小的Chrevron阻尼支撑，采用了改造系统。假设MI的两个长宽比沿周长排列，则进行分析。当前意大利法规中假设的四个参考地震级别的非线性时程分析表明，如果可以实现SDE上HYDB的激活而又不损害最大地震考虑下的结构安全性，则可以避免MI的IP和OOP失败（ MCE）。