Introduction
- Background
Civil engineering structures are now faced with increasing risks from natural or man-made hazards, such as earthquakes, wind, fire, explosion, and impact actions. The collapse of engineering structures will cause severe casualties and property losses to the society. It is of great significance to enhance the reliability and safety of the structure in hazards.
However, for some survived buildings with severe damages (usually with storey drift over 0.5%), the repair costs are so high that it is always more economical to demolish them [1]. It is reported by the ASCE Infrastructure Report Card that the cost for rehabilitation for civil engineering structures in the USA is estimated to be US$123 billion [2]. Moreover, even if the damaged buildings can be repaired, the downtime of the building function will cause significant indirect losses to the whole community. These consequences are not consistent with the sustainability guidelines proposed by ASCE that when optimizing the structure, not only the structural effects and responses to loads should be considered, but also the responses to and interaction with the surrounding environment and ecosystems [3]. It seems that the traditional survival-based safety design concept now has far fallen behind the sustainability requirements. Therefore, improving the resilience of engineering structures after hazards and minimizing its impact on the community are important parts to guarantee the sustainable development of the society.
In some third- and fourth-tier cities in mainland of China, there are still many low-rise and middle-rise residential buildings. The construction of these buildings often costs about 10-20 years of the household income. After hazards, the repair cost of the damaged buildings will exert huge economic pressure on the residents. Recognizing this, RSSsL will be committed to developing basic theories and application technologies on smart structures, by using material-based technology, innovative connections and components, or novel structural system, to enhance the resilience of steel structures subject to various hazards. By alleviating disaster damages and avoiding large residual drifts, the cost of the following repair work for the damaged structures can be significantly reduced, which can further promote the sustainable development of the society.
- Objective
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RSSsL aims to conduct advanced studies on the resilience of steel and smart structures subject to extreme actions. These include but not limited to earthquake, wind, fire, explosion, and impact that may significantly affect the robustness and structural integrity of steel structures. By conducting experimental studies, theoretical studies, and advanced numerical analyses, RSSsL will propose resilient-based design guidelines and recommendations for the profession. Cost-effective structural and smart elements and system will also be promoted in practical engineering. The final goal of RSSsL is to promote resilient steel structures design with the adoption of smart materials to alleviate the damage of buildings due to extreme actions. In particular, the advanced technologies developed will be applied to strengthen existing low-rise and middle-rise building structures subject to seismic action. The work of RSSsL will contribute to the sustainable development and construction to enhance the suitability of the society.
Research Team of the Lab
- Laboratory-in-charge
- Prof Michael CH YAM
- Members
- Prof K F Chung
- Dr Tak-Man Chan
- Dr Fang Cheng (Associate Prof, Tongji University)
- Dr Ke Ke (Associate Professor, Chongqing University)
- Collaborators
- Prof Zhou Xu-Hong (Professor, Chongqing University)
- Dr Ran FENG (Harbin Institute of Technology)
- Dr Zhang Jing-Zhou (Postdoc, PolyU)
- Dr Wang Jun-Jie (Postdoc, PolyU)
Venue: ZB207 at Block Z
Lab details
The RSSsL is equipped with state-of-the-art testing facilities to conduct full-scale tests of structural connections, elements, and systems subject to various types of loadings due to the hazards. Advanced numerical and computations techniques are also employed to complement the experimental results and enhance the understanding of the structural performance and behaviour of structural elements and systems to achieve structural resilience.
Research areas of the laboratory includes:
- Use of smart materials in earthquake resistant structures.
- We performed an experimental study of the cyclic performance of extended end-plate connections connected using SMA bolts instead of normal high strength bolts in the connections. The basic concept is to concentrate the earthquake-induced deformation into the connection, such that a ‘superelastic’ hinge can be formed via the elongation of the SMA bolts. Eight full-scale tests were conducted including seven extended end-plate connections with SMA bolts and one conventional extended end-plate connection with normal high strength bolts. The SMA connection specimens were shown to have excellent recentring abilities and moderate energy dissipation capability with an equivalent viscous damping up to 17.5%. The stiffness and strength of these connections mainly fell into the semi-rigid and partial-strength categories, respectively. The ductility, which was governed by SMA bolt rupture, was found to be dependent on the net threaded-to-shank area ratio of the bolts, where a lower ratio led to earlier bolt fracture over the net threaded cross-section. On the other hand, the conventional extended end-plate connection with High Strength bolts was shown to have good energy dissipation capability and ductility but with considerable permanent deformation. To enable a further understanding of the SMA connections, preliminary numerical models were established and validated by the test results.
