Modification of Dynamic Foundation Response Due to Soil-Structure Interaction

This paper presents the results from extensive parametric dynamic analyses of soil-structure systems that focus on the clear modification (increase or decrease) of the acceleration amplitude at the foundation with respect to the free-field, especially for squatty structures. Properties of the systems are selected such as to cover a wide range of meaningful geometries and materials for engineering practice. The results are presented in terms of weighted modification factors of the maximum foundation acceleration amplitude with reference to the corresponding maximum acceleration amplitude at free-field, for squatty and more slender structures. For the large majority of the studied systems, foundation acceleration decreases from the free-field by 10–15% on average. Nevertheless, acceleration demand at the foundation increases compared to the free-field, for 30% of squatty and for 15% of the more slender structures. Modification of the foundation acceleration amplitude is also correlated with the ratio of the predominant period of the input motion to the flexible-base system period. Finally, the findings of this study are compared with sparse available recorded data from the Seismic Hazard Harmonization in Europe database.     

Development of Collaborative Structure Analysis (CSA) System and Its Application to Investigate Effects of Soil-Structure Interaction

In this article, a collaborative structure analysis (CSA) system is developed for integrating different finite-element simulation programs. In this system, a simulated structure is divided into multiple substructures, and the interaction between the substructures is considered. Interfaces for the commercial finite-element program ABAQUS and for an open-source framework for structure analysis, OpenSees, are developed to achieve CSA integration. The CSA system is applied to analysis of a soil-structure interaction (SSI) problem, and the effects of SSI are investigated, and the efficiency and accuracy of the system are demonstrated.     

Real-Time Dynamic Hybrid Testing Coupling Finite Element and Shaking Table

In this article, a Simulink simulation block with the finite element function is developed on the basis of S-function and implemented as the numerical substructure of real-time dynamic hybrid testing. Thereby, a real-time dynamic hybrid testing system coupling finite element calculation and shaking table testing is achieved. Using the developed system, a shear frame mounted on the soil foundation is tested, in which the shear frame is simulated as the physical model and the foundation is simulated as the finite element model with 132 degrees of freedom. Several cases of the dynamic behavior of soil-structure interaction are studied.     

Experimental and Analytical Study of Seismic Soil-Pile-Structure Interaction in Layered Soil Half-Space

The dynamic interaction of pile foundations, embedded in a horizontally stratified soil profile, with superstructures under low to moderate earthquake excitation can be handled in different ways. In this article, the soil-pile-superstructure dynamic interaction problem has been investigated using the coupled finite element-boundary element method. Comparison with shaking table experiments of a small scale model pile shows a good correlation with the proposed method in terms of the kinematic response of pile foundations and the structural response. A parametric study of the proposed model has yielded important results essentially concerning the amplification factors of the pile foundation and the superstructure.     

粤东地区考古学文化与环境的互动

粤东地区全新世的考古学文化具有鲜明的地方特色,不同时间的古文化在文化面貌和生计方式上存在着明显差别。本文在分析粤东地区汉以前区域气候波动和海平面升降的基础上,探讨了该地区不同考古学文化聚落形态的特点以及人地之间相互作用的过程。     

Stylistic variability of stemmed obsidian tools (mata’a), frequency seriation,and the scale of social interaction on Rapa Nui (Easter Island)

Easter Island, or Rapa Nui, has been the focus of much research and speculation, particularly with reference to the island’s hundreds of giant, enigmatic statues and the set of conditions that supported their construction and transportation. In this paper, we analyze an abundant class of lithic artifacts, mata’a, to study of patterns of cultural transmission with implications for the evolution of groups, competition, and scale of socio-political organization among this island population. While these kinds of studies often draw upon assemblages of decorated ceramics, here we show how analysis of variability unconstrained by performance allows us to measure aspects of inheritance related to the manufacture of these artifacts. In the case of mata’a from Rapa Nui, we demonstrate that it is possible to reach falsifiable conclusions about the evolutionary dynamics that shaped the remarkable archaeological record on Rapa Nui.     

Modeling and testing polity boundaries in the Classic Tuxtla Mountains,Southern Veracruz,Mexico

Combined application of GIS modeling of polity boundaries and qualitative characterization of those boundaries in the Tuxtla Mountains, southern Veracruz, Mexico generated interesting questions and some answers regarding the regional political landscape. Not only did this process elucidate possible boundary locations, the process of evaluating these different hypotheses proved to be a useful exercise in characterizing the boundary and the nature of interaction between the polities controlled by Matacapan and Totocapan during the Classic period. I develop a seven variable classification for political boundaries to be used with coarse-grained settlement data.     

Stochastic Quantification of Soil-Shallow Foundation-Structure Interaction

This article highlights soil-structure interaction (SSI) effects on the seismic structural response accounting for uncertainties in the model parameters and input ground motions. A probabilistic Monte Carlo methodology was used to conduct approximately six million dynamic time-history simulations using an established rheological soil-shallow foundation-structure model. Considering the results yields outcomes that contradict prevailing views of the always beneficial role of SSI. In other words, the likelihood of having amplification in structural response due to SSI is large enough that it cannot be readily ignored. This research provides a significant first step towards reliability-based seismic design procedures incorporating foundation flexibility.     

Seismic Vulnerability Assessment of an Infilled Reinforced Concrete Frame Structure Designed for Gravity Loads

In the last decades, particular attention has been paid to the seismic vulnerability of existing reinforced concrete buildings designed for gravity loads only. Such buildings, designed before the introduction of capacity design in modern seismic codes, are very common, particularly in seismic prone countries of the Mediterranean area. Due to poor detailing and lacking of capacity design principles, high vulnerability has been highlighted in several past studies. In this article, inadequate seismic response and peculiar damage pattern are investigated by means of shake table tests performed on a 1:2 scaled 3-story infilled prototype. Particular attention is given to the role of beam-column joints and frame-panel interaction. The effectiveness of the EC8-based assessment approach is then evaluated; both linear and nonlinear numerical models, with different levels of sophistication, have been implemented in order to explore their behavioral aspects.     

Analytical Seismic Assessment of a Tall Long-Span Curved Reinforced-Concrete Bridge. Part II: Structural Response

The seismic assessment of special bridges, even under the hypothesis of full knowledge of site conditions, structural characteristics, and seismic activity at their location, is not an easy and straightforward task due to the complexities and uncertainties related to the finite-element modeling approaches, structural loading scenarios, and seismic analysis methodologies. In this article, a series of nonlinear static and dynamic finite-element analyses on the Mogollon Rim Viaduct are performed with consideration of both uniform and conditionally simulated non-uniform seismic motions. The failure modes of the bridge using different numerical modeling approaches are discussed, and the degree of sensitivity of its response to the different seismic assessment strategies is evaluated. The effect of the multi-component, multi-support and multi-directional excitations of ground motions on the design and response are studied, and the pros and cons of the commonly used structural analysis methodologies of bridges are also addressed. The numerical results of the present study provide a deeper insight into the nonlinear behavior of curved reinforced-concrete bridges, and suggest practice-oriented approaches for their seismic assessment.