- Connection systems in multi storey timber buildings under seismic action
- Wrzesniak, Daniela
Subject
- timber structures
- connection systems
- seismic load
- INGEGNERIA CIVILE E AMBIENTALE
- ICAR/08 SCIENZA DELLE COSTRUZIONI
Description
- 2012/2013
- Timber structures are currently experiencing a significant upturn. Reason for this are their distinct advantages concerning environmental and seismic aspects compared to steel and concrete structures. “Open space” and “multi-story” are no longer attributes which are exclusively used in connection with concrete and steel structures. Key aspects are the connection systems. Finding a high strength and ductile connection solution is especially challenging when seismic loads are considered. Designing a connection which does not undergo damage in a seismic event is another characteristic aimed for. This study presents a numerical investigation on the ductile behaviour of high strength tube type fasteners for post and beam joints. This new type of connection was developed at the University of Delft, the Netherlands. Different types of multi-story frames and a portal frame, made of glulam, were subjected to a set of different ground motion. The conducted incremental dynamic analysis revealed that q-factor of 2.5 and a high q-factor of 3.0 can be applied for portal frames and multi-story timber frames respectively. Although damage to timber parts is mostly avoided, the fasteners have to be replaced after a seismic event. The feasibility and behaviour of a conventional bolted connection for glulam walls subjected to high, seismic loads were experimentally studied. Both, the dynamic tests on timber walls with bolted anchorage and complementary tests on single dowelled connections showed, that brittle failure mechanisms can be delayed by applying simple design rules; such as increased spacing and distances. Utilizing reinforcement, ductile connection behaviour can be achieved. Irreversible damage to both timber and fasteners has to be anticipated when using this connection type. The applicability and response of an innovative viscous type damper in a glue laminated (Glulam) timber wall was numerically and experimentally studied. The high-force-to-volume (HF2V) viscous damper was developed at the University of Canterbury, New Zealand. The interaction between the devices and the flexibility properties of the timber wall and its connecting elements were investigated. The influence of additional weight on the self-centring behaviour of the damping devices was studied. The tests revealed that utilizing the HF2V devices in a timber wall, a damage-free system is achieved. The tests were completed without damage occurring to the dampers, the damper to wall connection and damper to foundation connection. Utilizing these devices result in high-strength, ductile and damage free design solutions for timber structures under seismic loads. The mathematical model which was developed based on the experimental findings can be used to determine the displacement time-history and structural reaction forces for a timber wall with HF2V viscous damping devices. This study contributes to the on-going research on suitable damage avoidance connection systems for multi-story, open plan timber structures under seismic loads. Advantages and disadvantages concerning the behaviour of the different systems under repetitive cyclic loading are highlighted as well as some specific areas that could benefit from further research. The presented results contribute to the understanding of the behaviour of connection systems which have so far not or not sufficiently been studied in timber elements subjected to seismic loading.
- XXVI Ciclo
- 1980
Date
- 2014-07-08T11:38:04Z
- 2014-07-08T11:38:04Z
- 2014-04-24
Type
- Doctoral Thesis
Format
- application/pdf
Identifier
urn:nbn:it:units-12543