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Solutions of the static Euler-Bernoulli equations of composite beam-columns with interlayer slip have been compared with an approximate theory. The inter-layer force was taken to be proportional to the inter-layer slip. The general solutions were obtained for four different sets of boundary conditions corresponding to the four Euler cases: clamped-free, pinned-pinned, clamped-pinned and clamped-clamped. A transverse static point load was considered. The beam was axially loaded. The contribution of the axial force to the bending moment, or equivalently the work done by the axial force on the beam due to its deflection, was taken into account in the second order theory and neglected in the first order theory. In the approximate theory the second order effects were described by an approximate magnification factor obtained from critical loads calculated by approximating the buckling length coefficients of the composite beam with interlayer slip by the buckling length coefficients of a solid beam. The contribution of second order effects to deflections and internal actions were calculated in terms of exact magnification factors at different stiffness of the composite action and the results were compared with the approximate theory. Two composite beams were considered. The first was a combination of concrete and timber and the second was a combination of concrete and steel. The positions of the maximum internal shear forces were shown to occur at different positions in the two layers of the beam of concrete and steel when the exact first and second order calculations were compared. The approximate theory was fairly accurate for the deflection but showed higher deviations for other quantities. The approximate theory needs further evaluation. The exact results have been obtained by analytical calculations in combination with numerical evaluation.

The Masonite Flexible Building (MFB) system is a complete timber building system for commercial and residential multi-storey houses. The system is for tall and large buildings with long floor spans. The MFB system uses prefabricated wall, floor and roof elements which are delivered in flat packages and erected on the construction site. The MFB system might be classified as a panel construction, where the load-carrying structure consists of composite lightweight timber I-beams mechanically integrated with a composite laminated wood panel called PlyBoard T. The I-beams and the panel form a strong and rigid carcass for wall and floor elements, making the system well suited for high rise construction. A key feature of the MFB system is the connection technique which enables swift erection of the system units on site. The PlyBoard T panels are provided with a continuous slot along the periphery. The slot is used as a general connection interface for the joining of the wall elements. The floor elements are suspended and hooked onto the bearing walls using sheet steel hangers, allowing swift assembling of the floor deck and enabling direct vertical wall-to-wall load transfer parallel to grain. The paper presents the construction principles, system components and units, erection technique, functional and architectural aspects of the Masonite Building System.

The vibrations of axially loaded composite beams with partial interaction are considered. The equations of motion and the pertaining boundary conditions are derived from Hamilton's principle. Mainly free — but also forced — vibrations are considered. The natural frequencies are calculated as a function of the axial force and the stiffness of the interaction between the layers. The analytical result obtained for the eigenfrequencies of the simply supported beam is taken as a starting point for an approximation of the eigenfrequencies of beams subject to other boundary conditions. The proposed approximation — which has no numerical fitting parameters — is shown to be in good agreement with the exact solutions, especially for the case of a beam clamped at both ends.

In this paper, the footfall-induced vibrations in typical timber and lightweight composite floors in residential buildings are investigated. The two-floor structures have approximately comparable distributed mass and that the transverse flexural stiffnesses of the two structures are not substantially different. An analysis is carried out to assess the floor acceptability of the two structures, based upon derived expressions as well as some design codes and guidelines such as the Eurocode. For the analysis, two cases are considered for each floor structure: a composite action and noncomposite action. It has been shown that use of composite action, under certain conditions, has more advantages than its noncomposite counterpart with respect to the floor acceptability for general residential applications. Moreover, the limitations of the different criteria of the codes, guidelines for assessing floor vibrations in timber and lightweight floor structures, and possible improvements of these criteria are discussed in this paper.

The authors investigate the human induced vibrations in typical composite timber floors inresidential buildings. Assessment methods given in different design codes and guidelines,such as the Eurocode, are discussed. A case study analysis based on the differentmethodologies is carried out to assess the acceptability of a specific timber floor. Twoextreme cases are considered: full and non-composite action. It is shown that compositeaction improves the floor acceptability for general residential applications. The limitations ofthe different criteria given in the codes and guidelines for assessing floor vibrations in timberfloor structures are discussed and, also, the possible improvement of these criteria.

The aim of this paper is to study the dynamics of partially interacting composite beams subjectedto axial loads, a situation occurring in e.g. beam-columns. The eigenfrequencies arederived for the simply supported composite beam subjected to an axial force. Measurements ofthe fundamental frequencies of a simply supported composite beam consisting of three layersare carried out considering different values of the applied axial force. The agreement betweenthe theoretical and experimental results is discussed. It is also shown that the application ofthe axial force introduces frictional moments at the boundaries, which make the experimentalboundary conditions deviate somewhat from those of an ideal simply supported beam.

In this work, a combined variational calculus and experimental approach are used to characterize the structural vibration behaviour of layered composite beams. Experimental dynamic tests are carried out on a composite simply supported beam with varied interaction strength between the layers. From the results, the influence of connections on the flexural natural frequencies, flexural deformation and damping is investigated. A good agreement between the derived theoretical equations and experimental results is obtained.

The authors present an experimental and theoretical study on a composite or hybrid element used in residential and agricultural buildings. The composite wall element consists of timber studs connected to a concrete plate by means of nail plate shear connectors. Experimental results are presented and compared with an analytical model for partial composite action. A good agreement is obtained between the analytical and experimental results. Also, some suggestions to improve the design of the composite element are discussed.

The lateral-torsional stability of vertically layered composite beams with interlayer slip is investigated in this paper, based on a variational approach. Vertically layered elements are typically used in timber engineering but also in case of laminated glass elements. Both across-longitudinal or vertical slip due to rotation and longitudinal or horizontal slip due to lateral deflection are discussed. The theoretical framework of the lateral-torsional buckling problem is given, and some engineering closed-form solutions are presented for partially composite beams under uniform bending moment. Simplified kinematical relationships neglecting the axial and vertical displacements of the sub-elements give unrealistic values for the lateral-torsional buckling moment. Refined kinematical assumptions remove this peculiarity and render sound buckling moment results. Inclusion of the horizontal and vertical slips significantly affect the lateral-torsional buckling moment of these vertically laminated elements. A single lateral-torsional buckling formulae is derived, depending on both the horizontal and the vertical connection parameters. (C) 2011 Elsevier Ltd. All rights reserved.

ABSTRACT: The Masonite Flexible Building (MFB) system is a complete timber building system for commercial and residential multi-storey houses. The system is subdivided into two market variants; XL and Light. The XL version is for tall and large buildings with long floor spans while the Light version is adapted for smaller buildings with lower loads. Though differing in technical performance, the functional criteria are the same for both variants. The MFB system uses prefabricated wall, floor and roof elements which are delivered in flat packages and erected on the construction site. The MFB system might be classified as a panel construction, where the load-carrying structure consists of composite light-weight timber I-beams mechanically integrated with a composite laminated wood panel called PlyBoard™. The I-beams and the panel form a strong and rigid carcass for wall and floor elements, making the system well suited for high rise construction. A key feature of the MFB system is the connection technique which enables swift erection of the system units on site. The plyboard panels are provided with a continuous slot along the periphery. The slot is used as a general connection interface for the joining of the wall elements. The floor elements are suspended and hooked onto the bearing walls using sheet steel hangers, allowing swift assembling of the floor deck and enabling direct vertical wall-to-wall load transfer parallel to grain. The paper presents the construction principles, system components and units, erection technique and functional and architectural aspects of the Masonite Building System.

KEYWORDS: Masonite Flexible Building system, multi-storey timber buildings, slotted-in connections, suspended connections, functionality requirements.