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A platform for research: civil engineering, architecture and urbanism
Experimental investigation of cross-laminated timber panels with realistic boundary conditions subjected to simulated blast loads
Highlights The paper deals with an experimental investigation of cross-laminated timber (CLT) elements subjected to simulated blast loading. The focus of the work was on the connections between the wall and the floor since such connections can deform inelastically and provide some of the critical energy dissipation needed. Current analysis and design methods assume the connections to be simply supported and while this assumption simplifies the analysis significantly, it ignores the important contribution of the connection. Connection types and associated failure modes are established and suitability of such connections for blast design are discussed. Also, current analysis methods and design provisions are evaluated and where appropriate suggestion are made to possible improvement in approaches. The study showed that the detailing of the connections appears to significantly affect the behaviour of the CLT slab. Typical detailing for platform construction where long screws connect the floor slab to the wall in end-grain performed poorly and experienced brittle failure. Bearing type connections generally behaved well. Yielding in the fasteners and/or angles brackets significantly reduced the energy imparted on the CLT slab and caused less displacement and thereby less damage in the slab. The study showed that using simplified tools such as single-degree-of-freedom (SDOF) models together with current available material models for CLT is not sufficient to adequately describe the behaviour and estimate the damage. The study also demonstrated that current blast design codes do not adequately address the design of connections in timber structures subjected to dynamic loads.
Abstract Recent research efforts have established key dynamic characteristics of cross-laminated timber (CLT) panels and developed parameters that are suitable for analysis and design. Despite such effort, no information is available on the critical role connections play in the behaviour of CLT when subjected to blast loads. The current study investigates a total of thirteen full-scale CLT wall panels with varying connection detailing by simulating the blast loading through a shock tube apparatus. The study found that typical connections with end grain screws into wall elements as well as angled double-threaded screws performed poorly and failed prematurely in tension perpendicular to grain. Reinforcing the connection with screws applied on the panel face did not mitigate the brittle failure. It was found that connection types where the wood is bearing on steel angles or directly on other wood members performed well even when under-designed according to the blast design standard. Whereas thin steel angles provided significant energy dissipation in bending of the angle resulting in reduced panel deflection and damage, thicker steel angles provided the energy dissipation through yielding in the screws as well rotational restraint of the panel ends. Using balloon type assemblies provided significant rotational restraint at the panel ends. The study also found that simplified models developed for idealized simply-supported conditions were not adequate to describe the behaviour of the system.
Experimental investigation of cross-laminated timber panels with realistic boundary conditions subjected to simulated blast loads
Highlights The paper deals with an experimental investigation of cross-laminated timber (CLT) elements subjected to simulated blast loading. The focus of the work was on the connections between the wall and the floor since such connections can deform inelastically and provide some of the critical energy dissipation needed. Current analysis and design methods assume the connections to be simply supported and while this assumption simplifies the analysis significantly, it ignores the important contribution of the connection. Connection types and associated failure modes are established and suitability of such connections for blast design are discussed. Also, current analysis methods and design provisions are evaluated and where appropriate suggestion are made to possible improvement in approaches. The study showed that the detailing of the connections appears to significantly affect the behaviour of the CLT slab. Typical detailing for platform construction where long screws connect the floor slab to the wall in end-grain performed poorly and experienced brittle failure. Bearing type connections generally behaved well. Yielding in the fasteners and/or angles brackets significantly reduced the energy imparted on the CLT slab and caused less displacement and thereby less damage in the slab. The study showed that using simplified tools such as single-degree-of-freedom (SDOF) models together with current available material models for CLT is not sufficient to adequately describe the behaviour and estimate the damage. The study also demonstrated that current blast design codes do not adequately address the design of connections in timber structures subjected to dynamic loads.
Abstract Recent research efforts have established key dynamic characteristics of cross-laminated timber (CLT) panels and developed parameters that are suitable for analysis and design. Despite such effort, no information is available on the critical role connections play in the behaviour of CLT when subjected to blast loads. The current study investigates a total of thirteen full-scale CLT wall panels with varying connection detailing by simulating the blast loading through a shock tube apparatus. The study found that typical connections with end grain screws into wall elements as well as angled double-threaded screws performed poorly and failed prematurely in tension perpendicular to grain. Reinforcing the connection with screws applied on the panel face did not mitigate the brittle failure. It was found that connection types where the wood is bearing on steel angles or directly on other wood members performed well even when under-designed according to the blast design standard. Whereas thin steel angles provided significant energy dissipation in bending of the angle resulting in reduced panel deflection and damage, thicker steel angles provided the energy dissipation through yielding in the screws as well rotational restraint of the panel ends. Using balloon type assemblies provided significant rotational restraint at the panel ends. The study also found that simplified models developed for idealized simply-supported conditions were not adequate to describe the behaviour of the system.
Experimental investigation of cross-laminated timber panels with realistic boundary conditions subjected to simulated blast loads
Côté, Dominic (author) / Doudak, Ghasan (author)
Engineering Structures ; 187 ; 444-456
2019-02-04
13 pages
Article (Journal)
Electronic Resource
English
Behaviour of Cross-Laminated Timber Panels under Cyclic Loads
| Springer Verlag | 2014