Experimental Campaign and Analysis on Double-Shear Wooden Connections

The presence of water in wooden elements is very important because it represents the key in the determination of the resistances of a wooden sample. The influences of the environmental conditions like temperature, relative humidity, wind, rain are constantly changing wood properties. The paper presents the different types of water that are found in a wooden piece together with experimental results on the displacement of double-shear wooden connections with wooden dowels that have been modified in two pre-established environments. The moisture content has been changed from 12% natural moisture of wood in normal building conditions to 8% and 16% for wood that is found in different climatic conditions. The experimental results are then compared with numerical calculations from the international standard Eurocode 5.

The Characteristics of Growth of Bacilli Formed Fouling on Wooden Constructions

Problem of biofilm formation have a great significance for environmental microbiological research. Biospheric microorganisms can form biofilm, that provide bacteria resistance to influence of different environmental factors. Some of the most common bacteria in biosphere are bacilli, among them there are film-forming strains.Bacillus spp.ia a well-known film forming microorganisms that colonize environmental objects. The biofilm fouling of underwater elements of small wooden constructions located on the Dnieper River near the city of the Dnipro (Ukraine) was studied. It was found that biofilms from surfaces of water constructions include bacilli. It is established that the mean values of CFU in samples from running and still water were (1.81±0.52)×108and (1.83±0.53)×108CFU / ml respectively per area of wooden sample approximately 1 cm2, while during the laboratory cultivation of the film, formed by these cultures on the plate, the number of cells was (4.90±0.93)×107and (4.60±1.07)×107CFU / ml per 1 cm2of the well’s bottom, which was an approximate limit of the content of cells of theBacillus spp.film per unit of area.