In a multi-storey residential housing project comprising of four 8-storey timber buildings, the bottom storeybeing designed with concrete and storeys 2-8 in timber, the vertical relative displacement, the temperature and the relativehumidity (RH) along one vertical channel in the external wall of one building has been monitored. Measurements startedduring construction and presented herein are results of 6.5 years of in-situ measurements. Displacement data was monitoredstorey-by-storey, with a sampling frequency of 1 measurement every 10-60 minutes. In another of the four buildingsadditional temperature and relative humidity measurements have been ongoing for about 5.5 years. These temperature andRH measurements were performed at six different locations in the building, at each location in eight positions through theexterior wall with a sampling frequency of 1 measurement every 15 minutes. The results show that the total verticaldisplacement over six storeys after 6.5 years of service life is approximately 23 mm as a yearly average, and over the yearthe displacement varies from this value by approximately ±2 mm. The main cause for the relative displacement is thedecrease of moisture content in the wood material leading to shrinkage after completion of the building. The resultsobtained show also that the exterior wall design of the building behaves well in terms of not comprising a general risk fordamp or mould in the timber core of the external walls.
Four buildings with clt-panels in their load bearing structure were built at the block Limnologen in Växjö, Southern Sweden. Their architecture is an example of the new ar-chitecture possible with this building system. Properties of these new structures are sought, one of these being their relative vertical displacement over time. These displacements are measured continuously for six storeys, up to now for just over two years. So far, the total measured dis-placements have reached a maximum of 21.1 mm over the 17.95 meter measuring length. Annu-lar variations of the displacements corresponding to the varying climate may be observed in the data.
This study relates to the topic of anchorage of shear walls. At times, eccentric forces between the sheathing and the anchoring devices may be introduced in the sill plate. In severe cases, such forces may cause the sill plate to split and to fail in a brittle manner. In this study, fracture mechanics are applied to develop a simple closed-form hand-calculation expression for estimation of the ultimate load capacity of the sill plate. Finite-element analyses using both linear elastic fracture mechanics (LEFM) theory and a nonlinear fictitious crack model are also used to predict the ultimate load-bearing capacity of the sill plate. The hand-calculation model is compared with the finite-element models, and good agreement is obtained. The results obtained with the various fracture mechanics models are compared with results available from previously performed experimental tests, and again good agreement is obtained. A general conclusion is that the LEFM theory is an adequate approach for the case studied and that the hand-calculation expression developed could be useful for structural design.
Wood specimens to each of which alaminate of carbon fibre reinforcement polymers(FRP) was glued (creating a lap joint in each case)were loaded to failure. A total of 15 specimens ofthree types differing in the glued length (anchoragelength) of the FRP laminate (50, 150 and 250 mmrespectively) were tested, their strength, stiffness andstrain distribution being evaluated. Synchronizeddigital cameras (charge-coupled devices) used intesting enabled strain fields on surfaces they weredirected at during the loading procedure to bemeasured. These results were also evaluated bothanalytically on the basis of generalized Volkersentheory and numerically by use of the finite elementmethod. The lap joints showed a high level ofstiffness as compared with mechanical joints. A highdegree of accuracy in the evaluation of stiffness wasachieved through the use of the contact-free evaluationsystem. The load-bearing capacity of joints ofthis type was found to be dependent upon theanchorage length in a non-linear fashion. The experimental,analytical and numerical results were shownto be in close agreement with respect to the strengthand the strain distribution obtained.
Four different elastic models for sheathing-to-framing connections are presented and evaluated on asingle connection level and on a shear wall level. Since the models are elastic in their nature they aresuitable mainly for cases where the sheathing-to-framing connections are subjected to monotonicallyincreasing displacements. Of the four models one is uncoupled and the others are coupled with respect tothe two perpendicular displacement directions in a two-dimensional model. Two of the coupled modelsare non-conservative, while the third is conservative, indicating a path independency with respect to thework done to reach a defined state of deformation. When the different models are compared it is obviousthat the uncoupled model gives strength and stiffness values higher than the others; however it is notobvious which of the models to use in a shear wall analysis, each of the models having its advantages anddisadvantages. For the experimental data used as input in the analyses of this study however, a couplednon-conservative model seems the most appropriate.