Seismic Response of Rigid-Block Assemblies: Experimental Studies and Validation of Discreet Element Numerical Tools

最近的振动台测试酒桶堆揭示了几个错位模式和各种模式的失败，包括滑动或摇摆的整个堆栈，滑动或摇摆的堆栈的上部，抬离的顶部桶，并在少数情况下明显扭曲的堆栈围绕其垂直轴。虽然最初的观察表明一个混乱的反应，进一步的实验结果表明，刚性块组件的动态响应可能比最初认为的要有序得多。当块组件的响应与激励的适当参数（不仅仅是加速度水平）和整个组件以及单个块的配置的适当参数相关时，出现顺序。需要提高我们的理解的动态响应的刚性块组件的动机本文提出的研究。这项拨款的主要目的是：（a）以实验方式验证单块摇摆反应的理论研究结果;（B）验证现有的离散和有限元软件的性能，以分析刚性块组件的动态反应;以及（c）建立一个可靠的程序，使工程师可以有信心地使用它来估计刚性结构的地震反应，在这个项目中，我们首先提出了一系列的振动台实验上的单个freestingandanchored块，以验证最近的理论研究结果，他们的摇摆响应地面震动。 该研究将检查数值工具预测整体位错模式和适当的失效模型的能力，并将记录其优点和局限性。最后，最可靠的现有软件将被用来构建一套漂移，旋转和倾覆谱的一个家庭的刚性块组件的利益。预计这项研究将建立一个实用的程序，估计刚性块组件的地震反应，并提供切实可行的改造建议，以提高其抗震性。

Recent shake table tests on wine-barrel stacks have revealed several dislocation patterns andvarious modes of failure including sliding or rocking of the entire stack, sliding or rocking of anupper portion of the stack, lift-off of the top barrels and in few occasions appreciable twisting ofthe stack around its vertical axis. While initial observations suggested a chaotic response, furtherexamination of the experimental results indicate that the dynamic response of rigid-block assemblies might be much more ordered than initially thought. Order emerges when the response of the block assembly is correlated with the appropriate parameters of the excitation (not just the acceleration level) and the appropriate parameters of the configuration of the entire assembly as well as these of the individual blocks. The need to improve our understanding of the dynamic response of rigid-block assemblies motivated the study proposed herein. The main objectives of this grant are: (a) to experimentally verify theoretical findings on the rocking response of single blocks; (b) to validate the performance of existing discrete and finite element software to analyze the dynamic response of rigid-block assemblies; and (c) establish a dependable procedure that engineers can use with confidence to estimate the earthquake response of rigid-block assemblies.In this project we first propose a series of shake table experiments on single free-standingand anchored blocks to validate recent theoretical findings on their rocking response under ground shaking. The study will examine the ability of numerical tools to predict the overall dislocation patterns and the appropriate model of failure and will document their advantages and limitations. Finally the most dependable existing software will be used to construct a set of drift, rotation and overturning spectra for a family of rigid-block assemblies of interest. It is expected that the study will establish a practical procedure for estimating the earthquake response of rigid-block assemblies and provide practical retrofit recommendations for enhancing their earthquake resistance.