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ABSTRACT:Heritage buildings are highly prone to long term damage from the microclimate, scourge and vandalism, which can result in damaged materials, structures, painting and cultural heritage items. This study will focus on finding the displacement of wood structural members through the use of a 3D laser scanner and the 4D concept of time. The results will compare the scans from different periods to find the difference (if any) in the structural member position. Wood structures usually consist of numerous wood members connected to form the structure. However, these members can be damaged in various ways such as physical mechanisms, chemical reactions, and biological corrosion. When damage to the wood structure occurs, the structural displacement can be affected, and if affected severely, can lead to a building collapse. Monitoring of the structural displacement is the best way to discover damage immediately and to preserve the heritage building. However, the Cultural Heritage Preservation Law in Taiwan prohibits the installation of monitoring instruments (e.g strain gauge, accelerometer) in historic structures (heritage buildings). Scanning the wood structure with 3D lasers is the most non-intrusive method and quickly achieves displacement through visualization. The displacement scan results can be compared with different periods and different members to analyze the severity of damage. Once the 3D scanner is installed, the whole building is scanned, and point clouds created to build the visual building model. The structural displacement can be checked via the building model and the differences are measured between each member to find the high risk damaged areas or members with large displacement. Early detection of structural damage is the most effective way means of preservation.

This paper presents a new approach to simulate the propagation of elastic and cohesive cracks under mode-I loading based on the vector form intrinsic finite element method. The proposed approach can handle crack propagation without requiring global stiffness matrices and extra weak stiffness elements. The structure is simulated by mass particles whose motions are governed by the Newton's second law. Elastic and cohesive crack propagation are simulated by proposed VFIFE-J-integral and VFIFE-FCM methods, respectively. The VFIFE-J-integral method is based on vector form intrinsic finite element (VFIFE) and J-integral methods to calculate the stress intensity factors at the crack tips, and the VFIFE-FCM method combines VFIFE and fictitious crack models (FCM). When the stress state at the crack tip meets the fracture criterion, the mass particle at the crack tip is separated into two particles. The crack then extends in the plate until the plate splits into two parts. The proposed VFIFE-J-integral method was validated by elastic crack simulation of a notched plate, and the VFIFE-FCM method by cohesive crack propagation of a three point bending beam. As assembly of the global stiffness matrix is avoided and each mass particle motion is calculated independently, the proposed method is easy and efficient. Numerical comparisons demonstrate that the present results predicted by the VFIFE method are in agreement with previous analytical, numerical and experimental works.

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<p><strong>Abstract.</strong> Most paintings were painted on the wood structure members for religion meaning and education to the prayers in the typical Taiwanese Temples. The damage of painting was induced by the micro-climate especially in the Relative humidity and Temperature various. Most typical Taiwanese temples were built by wood and brick structure with 1 open façade (semi-open space), outdoor air with different condition directly flows into indoor space to impact the material of paintings or structure members in subtropical Taiwan. When the materials absorb much damp or dry air, the volume will be expanded or shrink to damage the materials of painting layer or the basement layer. This study focuses on the damage risk assessment of painting on the wood structure members in the semi-open wooden historic temple. The test samples with painting were made by the cedar in the typical built method with wood protect oil, linen cloth, lime mortar, pigment, and surface protect oil. The test samples were put into the controlled chamber with temperature and relative humidity to test the peel off area by CNS 10757 to set up the safe range in different climate condition. The test results provide the risk assessment range in relative humidity with 55&amp;thinsp;%&amp;thinsp;±&amp;thinsp;15&amp;thinsp;% and in temperature with 25&amp;thinsp;°C&amp;thinsp;±&amp;thinsp;10&amp;thinsp;°C for safety range. The dangerous range may set ±10&amp;thinsp;% and ±5&amp;thinsp;°C from the safety range, and the very dangerous range should be destroyed the material from the boundary of EMC (Equilibrium Moisture Content), and phase change of materials. The risk assessment by benchmark in the temperature and relative humidity for easy announcing the managers to immediately trouble shooting.</p>