Progress and Perspectives of Geotechnical Anchor Bolts on Slope Engineering in China

Geotechnical anchoring technology is an important tool for disaster prevention and mitigation in slope engineering. Anchor bolts which are commonly used in slope engineering can be divided into prestressed anchors and non-prestressed anchors. Due to the superiority of anchor support technology, research on various aspects of anchor bolts, such as mechanical mechanism, anchorage effect, and the development of new-type anchor bolts, has been a significant research topic for scholars. This mini-review sums up the diverse past and current literature on anchor support technology of slope engineering in China. It focuses on the characteristics, applications, research methods, and practical cases of anchor bolts and briefly describes the history of slope anchor bolt development in China in the past 3 decades. Nowadays, the demand for engineering construction processes is increasing, and engineering geological conditions are becoming more complex, which promotes the development of anchor support technology. At the international level, achieving carbon neutrality is both an international trend and a general objective. Against the background of global commitment to carbon neutrality, the potential future perspectives for the developments of anchor support technology have been prospected in light of actual engineering needs.Peer Reviewe

Index to 1983 NASA Tech Briefs, volume 8, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1983 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Testing of Materials and Elements in Civil Engineering

This book was proposed and organized as a means to present recent developments in the field of testing of materials and elements in civil engineering. For this reason, the articles highlighted in this editorial relate to different aspects of testing of different materials and elements in civil engineering, from building materials to building structures. The current trend in the development of testing of materials and elements in civil engineering is mainly concerned with the detection of flaws and defects in concrete elements and structures, and acoustic methods predominate in this field. As in medicine, the trend is towards designing test equipment that allows one to obtain a picture of the inside of the tested element and materials. Interesting results with significance for building practices were obtained

Application of surrogate modeling methods in simulation-based reliability and performance assessment of civil structures

Structures and infrastructure systems are subjected to various deterioration processes due to environmental or mechanical stressors. Proper performance assessment approaches capable of detecting potential structural damage and quantifying the probability associated with structural failure are required to formulate optimal maintenance and retrofit plans that minimize the risk of failure and maximize the safety of structures. However, due to the presence of several sources of uncertainty that can affect the performance assessment and decision-making processes (e.g., uncertainties associated with loading conditions and performance prediction models), applying probabilistic methods, such as Monte Carlo simulation, is essential. In this context, a large number of simulations is generally required to quantify the low failure probability associated with civil structures. Executing the required number of simulations may be computationally expensive, especially if complex and/or nonlinear structural models (e.g., finite element models) are involved. The use of surrogate modeling tools such as artificial neural networks, polynomial chaos expansion, and kriging can help in reducing the computational costs associated with simulation-based probabilistic analysis. The research proposed herein aims to develop probabilistic approaches for performance assessment and damage detection of structures using advanced simulation-based techniques coupled with surrogate modeling. The proposed methodology is applied to quantify the risk of bridge failure due to flood events considering the impact of climate change. The approach was extended to establish the time-variant flood fragility surfaces for bridges under flood conditions. This approach (a) integrates deep learning neural networks into a simulation-based probabilistic approach to predict the future river streamflow necessary for assessing the flood hazard at the bridge location and (b) simulates the structural behavior of the bridge foundation under sour conditions. In addition, the proposed methodology is used to quantify the reliability of bolted and welded steel connections by integrating finite element analysis and surrogate models. Low-rank tensor approximation and polynomial chaos kriging surrogate models are adopted to perform Monte Carlo simulation and quantify the reliability of the investigated combination connection. Finally, artificial neural networks were used to develop a statistical damage detection and localization approach capable of evaluating the performance of prestressed concrete bridge girders using fiber optic sensors

Integration of Instrumentation and Computer Modelling to Understand and therefore Better Design and Represent the Rock bolt Support Behaviour

A safe and efficient ground control system is one of the most vital components of an underground mine’s operations. Current rockbolt ground reinforcement design methods do not consider the actual in-situ behaviour of the rockbolt. Instrumented rock bolts can be used to understand the actual rockbolt response under different loading conditions. Work done in this thesis aims to integrate the actual in-situ response of rockbolt with improved numerical modelling procedures for designing better ground support

Flexible bond wire capacitive strain sensor for a vehicle tyre

This thesis reports a novel flexible wire bond structured capacitive sensor design that can measure the strain in the tyres stably and reliably without any influence or disturbance to the tyre material during the measurement. An industry achievable fabrication method based on the design has been also investigated and it is also believed that there is a possibility of introducing the sensor into mass production. Bond wire technology, laser machining technology and photolithography technology are adopted to fabricate the strain sensor, in which the wire bonding technology is the most significant process for this design. An array of 25 micrometer bond wires that are normally employed for electrical connections in integrated circuits is built to create an interdigitated structure and generating approximately 10pF capacitance. The array that in an approximately 8*8 mm area consists of 50 wire loops and creates 49 capacitor pairs. The aluminium wires are bonded to a flexible PCB which is specially finished to allow direct bonding to copper surface. The wire array is finally packaged and embedded in a flexible and compliant material, polydimethylsiloxane (PDMS), which acts as the structural material that is strained. The implementations of the bond wire, the flexible PCB and PDMS embedding minimize the stiffness of the strain sensor while the PDMS can also prevent the sensor from any potential damage. When a tensile strain occurs, the wires are stretched further apart reducing the capacitance. On the contrary, the wires move closer and increase the capacitance if the strain sensor is compressed. Different from the traditional interdigital capacitor, the capacitance of the device is almost in a linear relationship with respect to the strain, which can measure the strain up to at least ±60000 micro-strain (±6%) with the resolution of 111 micro-strain (0.01%)

Review of Methodologies to Assess Bridge Safety During and After Floods

This report summarizes a review of technologies used to monitor bridge scour with an emphasis on techniques appropriate for testing during and immediately after design flood conditions. The goal of this study is to identify potential technologies and strategies for Illinois Department of Transportation that may be used to enhance the reliability of bridge safety monitoring during floods from local to state levels. The research team conducted a literature review of technologies that have been explored by state departments of transportation (DOTs) and national agencies as well as state-of-the-art technologies that have not been extensively employed by DOTs. This review included informational interviews with representatives from DOTs and relevant industry organizations. Recommendations include considering (1) acquisition of tethered kneeboard or surf ski-mounted single-beam sonars for rapid deployment by local agencies, (2) acquisition of remote-controlled vessels mounted with single-beam and side-scan sonars for statewide deployment, (3) development of large-scale particle image velocimetry systems using remote-controlled drones for stream velocity and direction measurement during floods, (4) physical modeling to develop Illinois-specific hydrodynamic loading coefficients for Illinois bridges during flood conditions, and (5) development of holistic risk-based bridge assessment tools that incorporate structural, geotechnical, hydraulic, and scour measurements to provide rapid feedback for bridge closure decisions.IDOT-R27-SP50Ope

2004 Research Engineering Annual Report

Selected research and technology activities at Dryden Flight Research Center are summarized. These activities exemplify the Center's varied and productive research efforts

Development of a Long-term, Multimetric Structural Health Monitoring System for a Historic Steel Truss Swing Bridge

The bridge stock across the United States is ageing, with many bridges approaching the end of their design life. The situation is so dire that the American Society of Civil Engineers gave the nation’s bridges a grade of “C+” in the 2013 edition of their Report Card on America’s Infrastructure. In fact, at the end of 2011, nearly a quarter of all bridges in the United States were classified as either structurally deficient or functionally obsolete. Thus, the nation’s bridges are in desperate need of rehabilitation and maintenance. However, limited funds are available for the repair of bridges. Management of the nation’s bridge infrastructure requires an efficient and effective use of available funds to direct the maintenance and repair efforts. Structural health monitoring has the potential to supplement the current routine of scheduled bridge inspections by providing an objective and detailed source of information about the status of the bridge. This research develops a framework for the long-term monitoring of bridges that leverages multimetric data to provide value to the bridge manager. The framework is applied to the Rock Island Arsenal Government Bridge. This bridge is a historic, steel truss, swing bridge that spans the Mississippi River between Rock Island, IL and Davenport, IA. The bridge is owned and operated by the US Army Corps of Engineers (USACE) and is a vital link for vehicular, train, and barge traffic. The USACE had a system of fiber optic strain gages installed on the bridge. As part of this research, this system was supplemented with a wireless sensor network that measured accelerations on the bridge. The multimetric data from the sensor systems was collected using a program developed in the course of this research. The data was then analyzed and metrics were developed that could be used to determine the health of the structure and the sensor networks themselves. Statistical process control methods were established to detect anomalous behavior in the short and long term time scales. Methods to locate and quantify the damage that has occurred in the structure once an anomaly has been detected were demonstrated. One of the methods developed as part of this research was a first order flexibility method. The SHM system this research develops has the desirable characteristics of being continuous temporally, multimetric, scalable, robust, autonomous, and informative. By necessity, some aspects of the developed SHM framework are unique and customized exclusively for the Rock Island Government Bridge. However, the principles developed in the framework are applicable to the development of an SHM system for any other bridge. Application of the SHM framework this research develops to other bridges has the potential to increase objectivity in the evaluation of bridges and focus maintenance efforts and funds on the bridges that are most critical to the public safety.Financial support for this research was provided in part by the Army Corps of Engineers Construction Engineering Research Laboratory (CERL) through a subcontract with Mandaree Enterprise Corporation.Ope

MARE-WINT: New Materials and Reliability in Offshore Wind Turbine Technology

renewable; green; energy; environment; law; polic