Finite element study of hyperstructure systems with modular light‐frame construction in high‐rise buildings

To answer both the growth of the world's urban population and the climate changes, new structural systems with high prefabrication levels and renewable materials need to be developed. A novel structural system that could enable the use of modular light‐frame construction in high‐rise buildings was modeled and analyzed. This system was achieved by having a hyperstructure carrying the loads of four‐story light‐frame superposed substructures. Two 20‐story hyperstructures, one using glulam and another one using reinforced concrete, were designed according to the 2015 National Building Code of Canada and compared. A simplified model for the light‐frame modules according to the CSA O86‐19 was proposed. The interaction between both systems and the impact on the substructures were analyzed. The results of the response spectrum analysis and dynamic wind analysis show that, with a glulam hyperstructure, modules could be connected to the columns and the floors or only to the floors. With a concrete hyperstructure, the modules must be connected to the columns and the cores. For both systems, the design of shearwalls on the short side of the modules is governed by the lateral deformation imposed by seismic forces, while the design of shearwalls on the long side of the modules is governed by the vertical deformation of the primary beams under gravity loads. Standard shearwall assemblies are sufficient to resist the shear induced by gravitational, wind and seismic loads. The analysis indicates that the system could be viable, but more research should be especially performed on the connections between the substructures and the hyperstructure

Mechanical behaviour and 3D stress analysis of multi-layered wooden beams made with welded-through wood dowels

This paper presents experimental and numerical investigations on multi-layered timber beams using welded-through wood dowels in place of traditional poly(vinyl acetate) (PVAc)-adhesives (or metallic nails). Four-layer beams were constructed with varying numbers of dowels, in each, and then loaded using four-points bending tests to evaluate the mechanical performance of these beams. The practical difficulties encountered in constructing deeper multi-layer beams are discussed and possible solutions which have been employed for the purpose of this work, and proved successful are presented. In order to investigate thoroughly the full potential of multi-layered beams with a very limited number of experimental studies, a 3D FE model has been presented, validated against experimental results and then used to study some influential parameters. The results showed that a reasonable bending stiffness of multi-layered beams is achievable with a good combination of material and geometric parameters.Deposited by bulk importSB. 19/02/201

The optimal design of sheet metal forming processes: application to the clinching of thin sheets

The production of high-strength clinched joints is the ultimate goal of the manufacturing industry. The determination of optimum tool shapes in the clinch forming process is needed to achieve the required high strength of clinched joints. The design of the tools (punch and die) is crucial since the strength of the clinched joints is closely related to the tools geometry. To increase the strength of clinched joints, an optimisation procedure using the response surface methodology, based on an adaptive moving target zone, is presented. The cost function studied here is defined in terms of the maximum value of the tensile force computed during the simulation of the sheets separation. Limitations on the geometrical parameters due to feasibility issues are also taken into account. The kriging interpolation is used to provide an approximation to the optimisation problem and to build the response surfaces

Modelling of Strengthened Steel Connections under Static and Cyclic Loading

The rehabilitation of steel structures with Fibre Reinforced Polymers (FRP’s) may appear less effective because they can be bolted or welded with steel plates that display the same mechanical properties. However, this technique has some unwanted consequences such as additional dead weight and an increased risk of corrosion. The aim of the proposed study, therefore, is to present a technique for modelling steel connections strengthened with FRP’s. Two types of composites: Carbon Fibre Reinforced Polymer (CFRP) and Glass Fibre Reinforced Polymer (GFRP) are considered. They are used to strengthen welded steel connections. The main objective consists in evaluating the effect of the reinforcement on the load-carrying capacity of these connections under monotonic and cyclic loadings. The steel is considered to behave in a linear elastic perfectly plastic fashion with isotropic strain hardening, and the FRP’s are assumed to behave linearly up to failure. The behaviour of the adhesive is modelled with the Cohesive Zone Model (CZM) available in Abaqus. Lastly, a parametric study is carried out to investigate the eventuality of strengthening connections made with I-sections, which are very common in practice

Modelling of Strengthened Steel Connections under Static and Cyclic Loading

The rehabilitation of steel structures with Fibre Reinforced Polymers (FRP’s) may appear less effective because they can be bolted or welded with steel plates that display the same mechanical properties. However, this technique has some unwanted consequences such as additional dead weight and an increased risk of corrosion. The aim of the proposed study, therefore, is to present a technique for modelling steel connections strengthened with FRP’s. Two types of composites: Carbon Fibre Reinforced Polymer (CFRP) and Glass Fibre Reinforced Polymer (GFRP) are considered. They are used to strengthen welded steel connections. The main objective consists in evaluating the effect of the reinforcement on the load-carrying capacity of these connections under monotonic and cyclic loadings. The steel is considered to behave in a linear elastic perfectly plastic fashion with isotropic strain hardening, and the FRP’s are assumed to behave linearly up to failure. The behaviour of the adhesive is modelled with the Cohesive Zone Model (CZM) available in Abaqus. Lastly, a parametric study is carried out to investigate the eventuality of strengthening connections made with I-sections, which are very common in practice

Experimental investigation on full-scale glued oak solid timber beams for structural bearing capacity

International audienceThis paper presents an experimental investigation on full-scale glued solid timer beams made of oak timber, for structural purposes. Similar experimental work was previously presented by the authors using beech timber (Tran et al., 2012). Here, the results from the previous work were served for comparison purpose between the performances of the two hardwood species (oak and beech). The obtained results showed that the glued solid timber beams made of oak timber perform relatively more much better than their counterparts made of beech timber, which was explained by the weakness in the finger-joint due to a poor adhesion within the beech timber

Experimental and numerical analyses of the structural response of adhesively reconstituted beech timber beams

International audienceThe aim of this work was to study the behaviour of adhesively reconstituted beams made of local beech timber. Experimental and numerical results are presented. Contributions of numerical modelling for the analysis of adhesively bonded assemblies for beech timber components are the main focus of the present paper. Numerical simulations are based on the Cohesive Zone Model (CZM) of Abaqus software to allow for accurate description of the progressive damage of the bond-lines up to final failure. The effects of several parameters were investigated ones the finite element model has been verified against experiments. The numerical results have showed that the modelling approach was convenient to study the behaviour of such beam systems with limited destructive tests, which are likely to be very expensive and time consuming. The parametrical study undertaken demonstrated a significant enhancement of the load-carrying capacity of beams by optimising the finger-jointing geometry

FE analysis and geometrical optimization of timber beech finger-joint under bending test

International audienceExperimental and numerical finite element results on the mechanical behavior of timber beech finger-joint are presented. Numerical simulations are based on the Cohesive Zone Model (CZM) of Abaqus software to allow for accurate description of the progressive damage of the bond-lines within the finger-joint up to failure. To increase the finger-joint resistance, the geometry of the finger-joint has been optimized using the Response Surface Method (RSM) and the Kriging interpolation. The finger length, the pitch and the tip gap have been defined as the design variables to optimize. The objective function has been defined in terms of the maximum bending force, obtained from four-point bending tests. Feasibility constraints on the design variables, conforming to the EN 14080 are also taken into account. The obtained results demonstrated clearly the potential in increasing the finger-joint resistance by optimizing its geometry