Experimental studies on cyclic behaviour of steel base plate connections considering anchor bolts post tensioning

This paper presents the experimental tests on cyclic behaviour of the base plate connections that are connected to the foundation with and without fully post tensioned anchor rods. The main aim is to evaluate these connections that are designed with available design procedures from the low damage aspect. Also, the effect of post tensioning on the seismic performance of this type of connection is presented. To characterize the base plate connection damageability, each column base was designed for a particular major inelastic deformation mode such as anchor rod yielding, yielding of the column, or column and base plate yielding. It is shown that considered joints are not able to be categorized as “a low damage”. Also, post tensioning of the base plate increases the rotational stiffness of the base, and results in more ductility of the column with low axial forc

SMOTEC: An Edge Computing Testbed for Adaptive Smart Mobility Experimentation

Smart mobility becomes paramount for meeting net-zero targets. However, autonomous, self-driving and electric vehicles require more than ever before an efficient, resilient and trustworthy computational offloading backbone that expands throughout the edge-to-cloud continuum. Utilizing on-demand heterogeneous computational resources for smart mobility is challenging and often cost-ineffective. This paper introduces SMOTEC, a novel open-source testbed for adaptive smart mobility experimentation with edge computing. SMOTEC provides for the first time a modular end-to-end instrumentation for prototyping and optimizing placement of intelligence services on edge devices such as augmented reality and real-time traffic monitoring. SMOTEC supports a plug-and-play Docker container integration of the SUMO simulator for urban mobility, Raspberry Pi edge devices communicating via ZeroMQ and EPOS for an AI-based decentralized load balancing across edge-to-cloud. All components are orchestrated by the K3s lightweight Kubernetes. A proof-of-concept of self-optimized service placements for traffic monitoring from Munich demonstrates in practice the applicability and cost-effectiveness of SMOTEC

Column Base Weak Axis Aligned Asymmetric Friction Connection Cyclic Performance

Recent low damage studies have been made on beam-to-column joints and braces. However, if there is significant yielding damage at the column bases, even with no upper structure damage, then the whole structure may need replacement. Therefore, there is a need to develop low damage base connections. This paper presents experimental tests of columns connected to base plate by weak axis aligned asymmetric friction connection (WAFC base) to evaluate if it performs as a low damage connection. Cyclic tests are conducted in-plane about the strong axis, and out-of-plane with and without applied axial force to drift ratios as high as 4%. Observations from the experimental tests demonstrate that this type of base connection can tolerate high levels of drift without any significant damage at the base. Some flange compressive yielding occurs especially when the column was subjected to axial force. Generally, no major damage happened which interrupt the performance of the column and the base connection, and it can be categorized as a low-damage connection. Also, the presented analytical model for estimation of WAFC performance provides a reasonable estimation of the experimental results

Spectral Assessment of the Effects of Base Flexibility on Seismic Demands of a Structure

Base flexibility of structures changes and can increase the demands on structural elements during earthquake excitation. Such flexibility may come from the base connection, foundation, and soil under the foundation. This research evaluates the effects of column base rotational stiffness on the seismic demand of single storey frames with a range of periods using linear and nonlinear time history analysis. The base rotational stiffness ranges considered are based on previous studies considering foundation and baseplate flexibility. Linear and nonlinear spectral analyses show that increasing base flexibility generally increases frame lateral displacement and top moment of the column. Furthermore, moments at the top of the columns and the nonlinear base rotation may also increase with increasing base flexibility, especially for shorter period structures. Since many commonly used baseplate connections may be categorized as being semirigid, it is essential to design and model structures using realistic base rotational stiffness rather than simply use a fixed base assumption. The overall results also illustrate the range of increased seismic demand as a function of normalized rotational stiffness and structural period for consideration in design

Spectral Assessment of the Effects of Base Flexibility on Seismic Demands of a Structure

Base flexibility of structures changes and can increase the demands on structural elements during earthquake excitation. Such flexibility may come from the base connection, foundation, and soil under the foundation. This research evaluates the effects of column base rotational stiffness on the seismic demand of single storey frames with a range of periods using linear and nonlinear time history analysis. The base rotational stiffness ranges considered are based on previous studies considering foundation and baseplate flexibility. Linear and nonlinear spectral analyses show that increasing base flexibility generally increases frame lateral displacement and top moment of the column. Furthermore, moments at the top of the columns and the nonlinear base rotation may also increase with increasing base flexibility, especially for shorter period structures. Since many commonly used baseplate connections may be categorized as being semirigid, it is essential to design and model structures using realistic base rotational stiffness rather than simply use a fixed base assumption. The overall results also illustrate the range of increased seismic demand as a function of normalized rotational stiffness and structural period for consideration in design