توسعه دستورالعمل جداسازی لرزه ای و کاربردهای قابل توجه در ترکیه
Abstract
1- Introduction
2- Seismic isolation design
3- Turkish seismic isolation design code for buildings
4- Seismic isolation applications for hospitals
5- Başibüyük Training and Research Hospital, Istanbul, Turkey
6- Adana Integrated Health Campus, Adana, Turkey
7- Conclusions and suggestions
References
Abstract
There is a special need to preserve the functionality of critical structures, such as hospitals, under severe earthquakes. In this sense, seismic isolation technology serves as a vital design method for the protection of their functionality. In Turkey, seismic isolation technology has been applied at an accelerated pace to new or retrofitted buildings and infrastructures for earthquake protection essentially after the 1999 Kocaeli Mw7.4 Earthquake. Several guidelines and a new official code are prepared to encourage and regulate the on-going applications. To enable the post-earthquake functionality of hospitals, the Ministry of Health public private partnership program foresees to build health campuses with seismic isolation. As of 2017, 21 health projects are complete or under construction with total investment of more than USD 23 billion. Following a general review of seismic isolation design, the essential features of the recent seismic isolation code are provided and compared with European, Japanese and US Codes. After a brief survey of base isolated hospitals in the world, two examples of large scale hospitals with seismic isolation are provided. The Basibüyük Training and Research Hospital in Istanbul, retrofitted with seismic isolation, encompasses 750 beds in 113.000 m2 floor area and is the largest hospital in the world retrofitted with a seismic isolation system consisting of 688 lead rubber and 154 sliding bearings. The newly built Adana Integrated Health Campus (City Hospital) has 430,000 m2 floor area and houses 1500 beds. With an isolation system composed of 1552 triple curved surface friction sliders, the hospital is currently the largest base isolated hospital in the world.
Introduction
Earthquake is a threat to human lives and assets. Population growth and increasing urbanization in earthquake-prone areas suggest that earthquake impacts on human populations will continue in the coming decades. Although, seismic design codes have been very successful in reducing collapse of structures, and have saved the lives of people, the same level of success is not seen in non-structural and business losses. In fact, in developed countries, over the past 20 years, most of the economic losses caused by earthquakes have resulted from non-structural damage and loss of facility use. Modern buildings contain sensitive and costly equipment that are vital in business, commerce, education and health care. The contents of these buildings are generally more costly and valuable than the buildings themselves. Furthermore, hospitals, communication and emergency centers, and police and fire stations must be operational immediately after an earthquake, when the need is greatest. In connection with the “Performance Based Seismic Design” approach, the expected performance objective for such critical facilities should be "fully operational", under exposure to the design basis earthquake (DBE). Conventional construction techniques may result in very high floor accelerations in stiff buildings and large inter-story drifts in flexible structures, causing difficulties in ensuring the safety of the non-structural components and contents. In order to achieve a "fully operational" performance, the most promising design approach is to use seismic isolation technique. Seismic isolation allows for the installation of specially designed bearing (isolator) units at the foundation or any other convenient floor level to substantially decouple the superstructure from earthquake motions. Increasing the fundamental period of vibration away from high spectral acceleration zone and the concentration of nonlinearity at the isolation interface serves to avoid the inelastic response of the superstructure and keeps the earthquake induced responses in the limited ductility level (Fig. 1). In addition, seismic isolators also reduce the floor accelerations and the inter-story displacements.