Abstract Although a number of precast concrete segmental columns (PCSC) have been built and developed in recent years owing to their various advantages, the dynamic responses of the column under blast loads are not well investigated. The characteristics of stress wave propagation within the column and their effects on the response and failure of the PCSC are still unknown. Understanding blast load induced stress wave propagation and the subsequent dynamic structural responses of PCSC is essential for blast resistant design and protection of PCSC. In this study the dynamic behaviours of the PCSC under blast loads are numerically investigated by using the explicit finite element software LS-DYNA. The numerical models and modelling techniques are carefully validated by three experimental blast tests from three different studies. The stress wave propagation within the cross-section and along the column height caused by blast loads is examined. The effect of steel tubes in protecting the PCSC from the blast loads is also investigated. It is found that the deformation of the column section under blast loads consists of two main phases, i.e. compression phase and expansion phase, in which failure of the concrete segment mostly occurs in the latter phase. Besides, the use of steel tubes has a marginal influence during the compression phase on the concrete section, but it becomes crucial in the expansion phase that the local failure of concrete segment, i.e. spalling and scabbing, is prevented by the confining effect. Furthermore, confining all concrete segments by steel tubes shifts the response of the PCSC from the local failure of the concrete segment to the global flexural response with fracture of the post-tensioned tendon. The influence of the blast location on the response of the column is also investigated in this study.

中文翻译：

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模拟爆炸荷载下预制混凝土节段柱的应力波传播和结构响应

摘要 尽管近年来建造和开发了许多预制混凝土管段柱（PCSC），但由于其各种优点，柱在爆炸荷载下的动力响应还没有得到很好的研究。柱内应力波传播的特性及其对 PCSC 响应和失效的影响仍然未知。了解爆炸载荷引起的应力波传播和 PCSC 的后续动态结构响应对于 PCSC 的抗爆设计和保护至关重要。在这项研究中，使用显式有限元软件 LS-DYNA 对 PCSC 在爆炸载荷下的动态行为进行了数值研究。数值模型和建模技术经过来自三项不同研究的三项实验性爆炸测试的仔细验证。检查了由爆炸载荷引起的横截面内和沿柱高度的应力波传播。还研究了钢管在保护 PCSC 免受爆炸载荷影响方面的作用。研究发现，爆炸荷载作用下柱截面的变形主要由压缩阶段和膨胀阶段两个阶段组成，其中混凝土管片的破坏主要发生在后一个阶段。此外，钢管的使用在压缩阶段对混凝土截面的影响很小，但在膨胀阶段，通过限制效应防止混凝土管段的局部破坏，即剥落和结痂变得至关重要。此外，用钢管限制所有混凝土段将 PCSC 的响应从混凝土段的局部破坏转变为后张预应力筋断裂的整体弯曲响应。本研究还研究了爆炸位置对柱响应的影响。