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The aim of the article is to present results of seismic analysis results of two real-sized timber frame buildings subjected to seismic excitations. The first model was insulated with mineral wool, the second one with polyurethane foam. Technology and specifications involved in both models construction is based on the previously conducted experimental research on timber frame houses, including wall panels tests, wall numerical models and study on material properties and precisely reflect results of the those research. During the seismic analysis reference node located in buildings were selected. In selected node displacement values were measured and compared between two analyzed models. The results of the numerical analysis presented in the article indicate that the application of polyurethane foam for a skeleton filling of the timber-frame building leads to the increase in stiffness as well as damping of the whole structure, which results in a considerable increase in the seismic resistance of the structure.

Pillar jib cranes are often mounted to existing floors with the use of an intermediate anchorage steel plate instead of using independent foundations. The process of designing such an intermediate plate for a pillar jib crane and a destruction pattern for plates of insufficient thickness are presented in this article. The required steps of the designing process are introduced and also the required level of detail for the numerical analysis. The aim of this paper is to provide a secure and safe approach to the design of such intermediate anchorage plates.

Wood frame buildings are very popular in regions that are exposed to different dynamic excitations including earthquakes. Therefore, their seismic resistance is really important in order to prevent structural damages and human losses. The aim of the present paper is to show the results of experimental tests focused on the dynamic response of wall panels of a wooden frame building with thermal isolation made of mineral wool and polyurethane foam. Firstly, the static and the dynamic mechanical analysis (DMA) tests were conducted so as to determine the basic thermomechanical properties of the analyzed isolation materials. Then, the elements of the exterior walls with two types of thermal insulation were tested under harmonic excitation for different amplitudes of displacement. The results of the static material tests indicate that the polyurethane foam behaves in a highly nonlinear way both during compression and tension. Moreover, the results of the DMA tests show that the storage and loss modulus of the polyurethane foam are significantly larger in relation to the values obtained for the mineral wool. The results of the dynamic tests on wall panels show that the use of polyurethane foam as thermal isolation leads to a substantial increase in stiffness and damping properties, as compared to the case when the mineral wood is used. [ABSTRACT FROM AUTHOR]

Wood-frame buildings are very common in regions that are exposed to earthquakes. Most of residential buildings are constructed using this technology; therefore, the seismic resistance of them is really essential in order to prevent human losses and structural damage. The aim of the present article is to show the results of the detailed numerical FEM analysis focused on the seismic behaviour of the wood-frame house with different in-wall insulation materials. The results of the study clearly indicate that using polyurethane (PU) foam instead of mineral wool leads to the increase in the rigidity of the structure and, therefore, to the substantial reduction in the structural response under different seismic excitations. The results also show that, generally speaking, the level of reduction in the displacement response increases with the increase in the magnitude of the earthquake, which even furthermore benefits the application of PU foam as an insulation material. It has also been concluded that the method of using PU foam can be successfully applied not only in the newly constructed wood-frame houses but also in existing ones since replacing the mineral wool with PU foam is relatively easy and not so much expensive. [ABSTRACT FROM AUTHOR]

The aim of this article is to present the results of a numerical modal analysis of two actual structures of timber frame buildings and the different behaviour due to the used insulation material. One model of the timber structure was filled with mineral wool, while the other with polyurethane foam. During the modal analysis, eigenvalues for both models have been determined. The results of the analysis clearly show the increase of stiffness and damping properties of skeletal constructions achieved by the use of polyurethane foam as the skeleton filling. The numerical model was based on prior experimental test on real scale single frame elements, therefore the result can be assumed to be adequate. [ABSTRACT FROM AUTHOR]

The aim of this paper is to show the numeric representation of experimental studies concerning the behaviour of exterior wall models of a timber-frame house under harmonic loading. A single wall model according to traditional technology of timberframe house walls (filling with mineral wool) was tested. The analysis was conducted for the following frequencies: 0.5 Hz, 1.0 Hz, 2.0 Hz and 5.0 Hz for various values of the specified displacement. A number of hysteresis loops were obtained for each of the tests. Based on them, the damping ratio as well as stiffness were calculated. The skeleton model filled with mineral wool (traditional technology) experienced serious damage under larger displacements. The results of the study have been used to propose a numerical model of wall filled with mineral wool. The proposed numerical model is consistent with the results for the values obtained during the experimental study, which proves the correctness of the adopted solution. [ABSTRACT FROM AUTHOR]

The soft-story failure is one of the most typical types of damage observed in buildings during earthquakes. The failure of an intermediate soft story of a structure results in large impact loading acting on the lower floors due to the fall of the upper stories. The aim of the present paper is to study the behavior of the structural members exposed to such extreme load conditions occurring under ground motion excitation. Special attention is paid to investigate the influence of the degradation of horizontal stiffness of columns on the response of the building during earthquake. The results of the study show that the stiffness degradation of building columns, due to impact caused by the fall of the upper stories, may have a considerable influence on the structural response. Moreover, the results clearly indicate that the time of impact plays a substantial role in the overall behavior of the building suffering from the soft-story failure. It has been shown that the structural response may be increased significantly if impact takes place when the building is in the range of its peak deformations during the earthquake, especially when the structure is just approaching the extreme position. [ABSTRACT FROM AUTHOR]

Conformations of the title compounds were examined using DFT calculations and NBO analysis in order to find the origins of their conformational preferences. The most stable conformations were TBC and TCBtype-1 for the 2,4- and 3,5-benzodioxonine derivatives, respectively. In both of these conformations the acetal moiety adopts the g±g± geometry. The NBO analysis yielded values of the stabilization energy associated with the stereoelectronic nO → σCO* interactions that were highest for conformations other than the global minima. Conformers displaying the strongest interactions followed different patterns of atom arrangement within the acetal moiety, namely g+g-, and those in which one or both of the torsion angles within the COCOC segment were close to 90°. Steric repulsion caused by alkyl substituents at the anomeric carbon was found to influence the strength of the nO → σCO* stabilization through modification of bond lengths and torsion angles. The adopted ground-state conformations result from accommodation of steric repulsions and stabilizing stereoelectronic interactions. It was shown that DFT calculations of conformational preferences of acetals together with GIAO prediction of 13C chemical shifts should be a useful methodology for studies on conformation and conformational equilibria of acetals in solution. [ABSTRACT FROM AUTHOR]

The transition from experimental studies to the realm of numerical simulations is often necessary for further studies, but very difficult at the same time. This is especially the case for extended seismic analysis and earthquake-resistant design. This paper describes an approach to moving from the experimental testing of an elementary part of a wood-frame building structure to a numerical model, with the use of a commercial engineering analysis software. In the presented approach, a timber-frame structure with polyurethane (PU)-foam insulation and OSB (oriented strand board) sheathing was exposed to dynamic excitation. The results were then used to generate a numerical 3D model of the wooden frame element. The process of creating the 3D model is explained with the necessary steps to reach validation. The details of the model, material properties, boundary conditions, and used elements are presented. Furthermore, the authors explain the technical possibilities for simplifying the numerical model in used software. Simplifying the model leads to a substantial reduction of calculation time without the loss of accuracy of results. Such a simplification is especially useful when conducting advanced numerical calculations in the field of seismic and dynamic resistant object design. [ABSTRACT FROM AUTHOR]

Pounding between adjacent buildings during ground motion may result in structural damage or lead to total destruction of structures. The research on the phenomenon has recently been much advanced; however, the analyses have been carried out only for concrete, steel, and masonry structures, while pounding between wooden buildings has not been studied so far. The aim of this paper is to show the results of detailed non-linear seismic analysis of inter-story pounding between the wood-framed buildings modelled by using the finite element method. Firstly, the modal analysis of the structures was conducted. Then, the detailed non-linear analysis of earthquake-induced collisions between two wood-framed buildings of different heights was carried out. The results of the analysis indicate that the behavior of both structures in the longitudinal as well as in the transverse direction is significantly influenced by interactions. The response of the taller building is increased in both directions. On the other hand, the response of the lower building is decreased in the longitudinal direction, while it is increased in the transverse one. The results of the study presented in the paper indicate that, due to deformability of buildings made of wood, structural interactions may change their responses much more, as compared to steel, reinforced concrete, or masonry structures. [ABSTRACT FROM AUTHOR]

Temperature-dependent (1)H and (13)C-NMR spectra of the title compounds are presented. Coalescence effects are discussed and assigned to dynamic process--the interconversion of bicyclic system. The free energies of activation covered the range 39-52 kJ/mol. The dioxepane ring adopts twist-chair (TC) conformation. GIAO/DFT calculation of isotropic shieldings for the set of low-energy conformations showed that only one conformer is present at 298 K in solution that matched well with experimental data., (2010 John Wiley & Sons, Ltd.)

DFT/B3LYP calculations of the ground-state conformation of eight cyclic and acyclic acetals are presented and compared with experimental data. Results of single-point GIAO/DFT calculations at five different levels of theory show that isotropic shieldings need to be empirically scaled to achieve agreement with experimental chemical shifts. Statistical evaluation of data indicates that the most accurate prediction of 13C chemical shifts is achieved at the MPW1PW91/6-311G** level of theory. An empirical equation describing the relationship between delta values and shielding constants is postulated. This equation has been applied to the non-chair ground-state conformation of the six-membered acetonide and to the conformationally flexible benzodioxonine derivative. The agreement observed between the experimental and predicted chemical shifts shows that calculations at the MPW1PW91/6-311G** level of theory are adequate for addressing questions of conformation., (Copyright 2004 John Wiley & Sons, Ltd.)