دانلود رایگان مقاله توسعه استاندارد سازگار ارزش طراحی برای کامپوزیت چوب پلاستیک

Abstract

Bio-based materials, such as wood–plastic composites (WPC), have gained the interest of the resource-intensive building industry. Presently, this novel composite is being used in decking and cladding. The structural design of façades made from WPC compounds, however, has been difficult in the past due to a lack of design principles and experience. In this case study a design concept is developed, which combines material attributes describing the strength loss of the material due to different weathering processes on façades. Although this approach is widely used for approvals of cladding kits in Central Europe, it has not yet been used for WPCs. This paper is unique because for the first time research findings taken from a literature review on WPC attributes are used to obtain a realistic WPC design value for engineered façades. Simulations of WPC aging in three main categories predicted a strength loss of approximately 50% compared to the virgin material. Nevertheless, a WPC material design value which includes the effects of material aging is still useful for a façade planner’s practical work in view of the mandatory codes and standards in this field.

5. Conclusions

Relevant codes and standards were reviewed in this paper in order to develop a WPC cladding design value for target application conditions. To assess the suitability of wall cladding products, fac¸ ade planners are obliged to perform strength calculations, which take into account the loads and environmental impacts on buildings. Such calculations are based on material design values that are usually obtained from product approvals. It is demonstrated that in the absence of design values, a WPC cladding manufacturer can use available results obtained from the compound supplier or from initial tests which are required to be carried out prior to commercialization. This allows even small and medium-sized manufacturers to render their product attractive for the professional segment where engineers and contractors dominate product selection. It should be noted that the results of this case study are not free of uncertainties because they are based on findings from different WPC compounds. Research publications mainly deal with single aspects of WPC testing, and with investigations that focus on specific WPCs. Despite this limitation, a concept is derived in this publication that can be used by the WPC industry for the benefit of fac¸ ade planners. From the current practitioner’s point of view the derived WPC design value is sufficiently reliable for use in fac¸ ade strength calculations, because it is mainly based on codes and standards. This paper therefore fills a gap that exists in current WPC fac¸ ade design and will help move current WPC cladding products into the professional segment of fac¸ ade products.