This paper presents a study of two-pin arches of constant cross-section that are moment-less under statistically prevalent (permanent) load. The arches are defined by analytical form-finding previously reported in Lewis (2016) [1]. The work provides guidance regarding the solution process, and expressions for reactions and axial forces. New analytical results include the derivation of the arch length, and a method for finding co-ordinates of individual arch segments in pre-fabricated construction. The accuracy of the shape prediction for inextensible moment-less arches is good, compared to the results from elastic models. Case studies report on medium and large-span arches, with the latter resembling the iconic Hoover Dam arch. Comparative studies of the moment-less and conventional arch forms (mostly of parabolic configuration), are carried out using permanent and variable loads. Additionally, the Hoover Dam arch is analysed for a discrete load transfer from the deck. Circular arches are analysed for the permanent load only, and are shown to be extremely inefficient in load resistance. Moment-less arches are found to provide a minimal stress response to loading and require least amount of material – a feature observed in natural objects. These characteristics are important from a durability perspective – a key concern for our future infrastructure.

本文介绍了具有恒定横截面的两针脚拱的研究，这些拱脚在统计上普遍存在的（永久）载荷下是无力矩的。通过先前在Lewis（2016）[1]中报告的分析形式发现来定义拱门。这项工作提供了有关求解过程的指导，以及反作用力和轴向力的表示形式。新的分析结果包括拱长的推导，以及一种在预制结构中查找各个拱段坐标的方法。与弹性模型的结果相比，不可伸展的无弯拱的形状预测的准确性很好。案例研究报告了中跨和大跨度拱门，后者类似于标志性的胡佛水坝拱门。比较了无弯矩拱形和常规拱形（主要是抛物线形），使用永久载荷和可变载荷来执行。此外，还对胡佛水坝拱门进行了分析，以分析甲板上的离散荷载。圆拱仅针对永久载荷进行分析，并且显示出极低的载荷抵抗力。无矩拱门被发现对负载的应力响应最小，所需的材料量最少-这是在自然物体中观察到的特征。从耐久性的角度来看，这些特性很重要-这是我们未来基础架构的关键问题。无矩拱门被发现对负载的应力响应最小，所需的材料量最少-这是在自然物体中观察到的特征。从耐久性的角度来看，这些特性很重要-这是我们未来基础架构的关键问题。无矩拱门被发现对负载的应力响应最小，所需的材料量最少-这是在自然物体中观察到的特征。从耐用性的角度来看，这些特性很重要-这是我们未来基础架构的关键问题。