The main objective of this work is to present a numerical model to predict the effect of wood density in unprotected wood connections with an internal steel plate (wood–steel–wood), when comparing with the same connections using passive protection with gypsum plasterboard, submitted to fire conditions. Wood–steel–wood connections are made of four wood members, two on each side, with an internal steel plate that connects the pieces using steel dowel fasteners. First, analytical methodologies according to Eurocode 5 part 1-1 were used to design the connections at room temperature. After that, to predict the fire exposure and the connection ability, a numerical model was performed which permits to compare the fire resistance in wood–steel–wood connections without and with passive protection following the Eurocode 5 part 1-2. Results of the temperature and the wood char layer depth were compared using three different wood densities. The evolution of the charring rate was calculated in different locations of the connections and compared with the analytical value proposed by the Eurocode 5 part 1-2.

中文翻译：

---

预测火灾下有和没有被动保护的木材-钢-木材连接中木材密度影响的数值模型

这项工作的主要目的是提出一个数值模型来预测木材密度在与内部钢板（木-钢-木）的无保护木材连接中的影响，当与使用石膏石膏板被动保护的相同连接进行比较时，提交到火灾条件。木-钢-木连接由四个木构件组成，每侧两个，内部钢板使用钢销紧固件连接部件。首先，根据欧洲规范 5 第 1-1 部分的分析方法用于在室温下设计连接。之后，为了预测火灾暴露和连接能力，执行了一个数值模型，该模型可以比较没有和有被动保护的木-钢-木材连接的耐火性，遵循欧洲规范 5 第 1-2 部分。使用三种不同的木材密度比较温度和木炭层深度的结果。在连接的不同位置计算炭化率的演变，并与欧洲规范 5 第 1-2 部分提出的分析值进行比较。