Design of floor-to-wall connections in hybrid structures - Study of robustness in CLT floor to concrete wall connections
Typ
Examensarbete för masterexamen
Program
Structural engineering and building technology (MPSEB), MSc
Publicerad
2021
Författare
ALIBASIC, ARMEL
VOCAL, VIDAL
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The construction industry has taken an approach towards implementing sustainable
alternatives combining conventional concrete or steel elements with timber. Concrete
has been the most popular construction material in the past century, but the amount
consumed has considerable negative environmental impacts compared to its
alternatives. In an effort towards a sustainable industry, construction of hybrid
structures is encouraged. These types of structures combine different materials,
allowing more diversity in the structural design. However, replacing structural elements
with “green” materials needs further study about its performance regarding robustness
and the prevention of progressive collapse. Following the availability of prefabricated
timber in the Swedish construction industry, this material is to gradually replace
concrete elements. Limited research currently exists regarding robustness criteria when
combining timber and concrete. The Eurocode and national design guidelines provide
design procedures for each individual material, but not the effects when combined in a
hybrid structure. Additionally, cross-laminated timber has different material properties
and structural behavior than regular solid timber which are not considered.
Referral to external research articles and foreign guidelines were studied to understand
the mechanical behavior and determine a design approach to reach robustness demands.
The aim of this thesis is to study and design the connection of a CLT floor to a precast
concrete wall by performing a case study of a housing project in Malmö. Results
showed that a combination of the tying method with an alternate load path analysis,
cross-laminated timber could provide the ductility and strength necessary for load
redistribution to alternate load paths. Precast concrete walls together with CLT floors
worked together to each contribute to the overall robustness with the capability of
triggering different collapse resistance mechanisms such as hanging action and deep
beam behavior. The replacement of hollow-core slabs with CLT floors provided a
reduction of 30% in the self-weight and negative values in carbon dioxide equivalent
emissions where timber stored more carbon dioxide than the amount required for their
production.
Beskrivning
Ämne/nyckelord
Robustness, progressive collapse, deep beam behavior, alternate load path , analysis, hybrid connections, redundancy, cross-laminated timber, carbon dioxide , equivalents