"三向连接构造" can be translated as "three-way connection structure" or "tri-directional connection configuration" in English, depending on the specific context and the level of technicality desired.
"Three-way connection structure" is a straightforward and commonly used translation that clearly conveys the idea of a structure that connects in three different directions.
"Tri-directional connection configuration" is a more technical and precise translation, often used in engineering or architectural contexts where a detailed description of the connection's orientation and functionality is required.