The solution to the classic so-called Couplet’s problem was provided more than a century ago, and recently, in the frame of limit equilibrium analysis, elliptical and pointed arches have also been carried out. Albeit triangular form of arches is the structural precursor of the mentioned ones, its mechanical behaviour has not been sufficiently researched. Therefore, the present paper elaborates in detail the thrust line analysis of different types of triangular arches under self-weight. Hence, with respect to vertical, normal, horizontal and radial stereotomy, the closed-form expression of the corresponding thrust line, as well as the numerical values for the minimum thickness, is derived.

中文翻译：

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三角拱的推力线分析

一个经典的所谓对联问题的解决方案已经有一个多世纪的历史了，最近，在极限平衡分析的框架中，椭圆形和尖头拱形也已经进行了。尽管三角形的拱形是上述拱形的结构先驱，但对其力学性能的研究还不够充分。因此，本文详细阐述了自重作用下不同类型三角拱的推力线分析。因此，关于垂直，法向，水平和径向的构造，导出了相应的推力线的闭合形式以及最小厚度的数值。