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Advisor(s)
Abstract(s)
O principal objetivo deste trabalho é estudar o comportamento de ligações (prote-gidas e não protegidas) do tipo madeira-aço-madeira (M-A-M) sujeitas a corte duplo, com cavilhas como ligadores e uma placa de aço como membro central. As ligações com ca-vilhas são utilizadas essencialmente para transmitir cargas elevadas. Para cada ligação em estudo foram utilizados diferentes diâmetros de ligadores e diferentes forças aplicadas à temperatura ambiente ou em situação de exposição ao fogo. Foram admitidas cargas de 25, 50, 75 e 100 kN, com diâmetros de cavilhas de 10, 12, 14 e 16 mm. A espessura dos elementos de madeira variou entre 45, 50, 55 e 60 mm, assim como a placa central de aço com espessuras de 5, 6, 8 e 10 mm. O número de ligadores varia de ligação para ligação, bem como a sua disposição, sendo que no presente estudo considerou-se a disposição dos ligadores em uma e duas filas. A ação do fogo na ligação foi imposta pela curva norma-lizada ISO834. Os elementos de madeira são constituídos por madeira do tipo laminada colada de bétula amarela com características equivalentes ao tipo GL28H. Nas ligações com proteção foram considerados três tipos de gesso de forma a obter um melhor isola-mento da ligação em situação de exposição a um incêndio. Foram utilizadas as equações simplificadas presentes no Eurocódigo 5, parte 1-1 e parte 1-2, para obtenção dos resul-tados analíticos tanto para a resistência mecânica da ligação como para a resistência tér-mica em situação de fogo. Foram desenvolvidos modelos numéricos para análise mecâ-nica e análise térmica, e assim permitirem verificar o efeito dos elementos ligadores, da placa de aço e das placas de gesso no efeito do avanço da camada carbonizada.
The main objective of this work is to present wood-steel-wood (W-S-W) connec-tions (with or without insulation) in double-shear, joined by steel dowel fasteners and a steel plate as the central member. Joints with dowels are used in timber construction to transmit high loads. For each studied connection, different dowel diameters and external applied tensile loads at ambient temperature and in fire situation shall be taken in account. Were analysed tensile loads of 25, 50, 75 and 100 kN, dowels diameters of 10, 12, 14 and 16 mm. The wooden board thickness was equal to 45, 50, 55 and 60 mm and steel plate thickness of 5, 6, 8 and 10 mm. The number of dowels will vary from connection to connection and vary in their disposition. The studied dowels were rearranged in two rows or in only one. The connection behaviour was studied when exposed to the standard fire curve ISO834. In the wood plates will be used a glue laminated wood, as yellow birch, with characteristics equals to GL28H. In W-S-W protected connections three types of gypsum will be used in order to obtain a better insulation. Using the proposed simplified equations from Eurocode 5, part 1-1 and part1-2, all analytical results were obtained at ambient and high temperature. A numerical structural and thermal analysis was used to verify the effect of the steel dowels, steel plate and gypsum in the wood charring rate evolution.
The main objective of this work is to present wood-steel-wood (W-S-W) connec-tions (with or without insulation) in double-shear, joined by steel dowel fasteners and a steel plate as the central member. Joints with dowels are used in timber construction to transmit high loads. For each studied connection, different dowel diameters and external applied tensile loads at ambient temperature and in fire situation shall be taken in account. Were analysed tensile loads of 25, 50, 75 and 100 kN, dowels diameters of 10, 12, 14 and 16 mm. The wooden board thickness was equal to 45, 50, 55 and 60 mm and steel plate thickness of 5, 6, 8 and 10 mm. The number of dowels will vary from connection to connection and vary in their disposition. The studied dowels were rearranged in two rows or in only one. The connection behaviour was studied when exposed to the standard fire curve ISO834. In the wood plates will be used a glue laminated wood, as yellow birch, with characteristics equals to GL28H. In W-S-W protected connections three types of gypsum will be used in order to obtain a better insulation. Using the proposed simplified equations from Eurocode 5, part 1-1 and part1-2, all analytical results were obtained at ambient and high temperature. A numerical structural and thermal analysis was used to verify the effect of the steel dowels, steel plate and gypsum in the wood charring rate evolution.
Description
Keywords
Ligação M-A-M Madeira Aço Gesso Cavilha Camada carbonizada Fogo Corte duplo