Applications of Tensegrity Structures in Civil Engineering

Getechnical monitoring by digital precise photogrammetry

This book provides a complete and clear introduction to the use of adhesives to form load-bearing joints in bridges, civil engineering and building structures. Recent advances in adhesive technology have led to a rapid growth in the use of adhesives and in many cases, the use of adhesives can prove more convenient, less expensive, stronger, and more durable than traditional methods of joining. The first part of this book addresses the crucial factors involved in the formation of a successful adhesive joint, including adhesive selection, surface preparation, joint design, fabrication and protection from the environment. The second part of the book describes the growing uses of adhesives to repair and strengthen existing structures, in addition to describing their use in new constructions and applications which are now being developed for the future. The connections between the two parts of the book are brought out wherever possible so that the links between theory and practice are emphasized. The book gives the reader all the information required to fully exploit the economic and technical advantages of adhesives over conventional methods. Professional civil and structural engineers in higher education and industry will find this book invaluable as will graduate students of construction.

In this paper a new approach for quantitative non-destructive testing (NDT) of near-surface structures in civil engineering (CE) with active thermography is presented. It adopts the method known as pulsed phase thermography (PPT) for the special requirements of NDT-CE and was developed in a German research project of the Federal Institute for Materials Research and Testing (BAM) in cooperation with the Technical University of Berlin. The new quantitative concept that might be understood as a square pulse thermography in frequency domain or an amplitude-expanded PPT with square pulse heating is based on the thermal diffusivity of the material and the characteristic frequency of the negative maximum phase and amplitude contrast. It aims at complementing the established approaches for defects depth calculation for measurements with long heating and observation times quite usual at active thermography in CE but is easily extendable to other fields of application. After an introduction to the basics of active thermography in CE and the thermography concept of BAM, qualitative results of several case studies will be presented. The main focus of the last section of this contribution is on applications of the new quantitative approach at test specimens of BAM to determine the concrete cover of artificially manufactured defects.

In the innovation and development of intelligent materials, civil engineering structure health monitoring system belongs to the system with modern information engineering software as the core development platform. High-performance sensors and related testing technology provide a new idea for the construction of civil engineering structure intelligent health monitoring system. The civil engineering health monitoring special structure provides a unique platform and completes the relevant design, the civil engineering structure design work for dynamic monitoring, but also can judge the characteristics of the application structure and the environment, in order to achieve the maintenance of the civil engineering structure. In this paper, the application performance of the intelligent health monitoring system platform for civil engineering structures based on intelligent sensing materials is further analyzed based on the research achievements of Chinese researchers in the recent years.

With the rapid development of society and the economy, people's life and property safety importance is also more and more high. Especially the occurrence of the Wenchuan earthquake, people on whether the application of civil engineering construction damping scientific and rational approach was questioned. How to ensure the quality of civil engineering construction, to avoid in the event of earthquakes and other natural disasters, the emergence floor crash event, is an issue for all engineering designers and builders focus on. Because of the relationship with all life safety, so how to use rational scientific method damping to the construction of civil engineering structures is very important and necessary. This study from the passive control, active control, semi-active control and hybrid control methods start with four damping research and analysis, combining their research status. The Benchmark problem of structure control has carried on the simple introduction. Focusing on civil engineering structure vibration control method of systematic review, so as to the future of civil engineering structure suspension construction provides the certain reference function

PROBLEM TO BE SOLVED: To provide a technology for preventing the movement of an inside filling material caused by external force such as billows, and breakage caused by the wear of a bag body, which are problems in installing conventional civil engineering bag bodies, even if the conventional civil engineering bag bodies are used as they are. SOLUTION: This civil engineering structure is constituted by arranging a plurality of civil engineering bag bodies 1 formed using a synthetic fiber net and filled with the inside filling material, putting a net 2 over the plurality of arranged civil engineering bag bodies 1, and connecting the put net 2 to the lower parts of the civil engineering bag bodies 1 through ropes or belts 3 in the tensed state of the ropes or belts 3. COPYRIGHT: (C)2006,JPO&NCIPI

Smart ROS-regulating biomimetic hydrogel promotes scarless diabetic wound healing via macrophage reprogramming.

Cooling towers in general belong to the largest structures in civil engineering, so that its studies are of important significant in theories and economical value in engineering. Since then the collapse of Ferry-bridge cooling towers in Britain during severe wind conditions in 1965, the interest in the static, dynamic, and stability behaviour of these towers has increased considerably.

Equivalent models of corrugated panels

The inspection of building structures, especially bridges, is currently made by visual inspection. The few non-visual methodologies make use of wired sensor networks, which are relatively expensive, vulnerable to damage, and time consuming to install. Systems based on wireless sensor networks should be both cost efficient and easy to install, scalable and adaptive to different type of structures. Acoustic emission techniques are an additional monitoring method to investigate the status of a bridge or some of its components. It has the potential to detect defects in terms of cracks propagating during the routine use of structures. However, acoustic emissions recording and analysis techniques need powerful algorithms to handle and reduce the immense amount of data generated. These algorithms are developed on the basis of neural network techniques and - regarding localization of defects - by array techniques. Sensors with low price are essential for such monitoring systems to be accepted. Although the development costs of such a system are relatively high, the target price for the entire monitoring system will be several thousands Euro, depending on the size of the structure and the number of sensors necessary to cover the most important parts of the structure. Micro-Electro-Mechanical-Systems and hybrid sensors form the heart of Motes (network nodes). The network combined multi-hop data transmission techniques with efficient data pre-processing in the nodes. Using this technique, monitoring of large structures in civil engineering becomes very efficient including the sensing of temperature, moisture, strain and other data continuously. In this paper, the basic principles of a wireless monitoring system equipped with MEMS sensors is presented along with a first prototype. The authors work on details of network configuration, power consumption, data acquisition and data aggregation, signal analysis and data reduction is presented.

Fiber-reinforced polymer (FRP) composites have emerged as promising next-generation materials for advanced structures in civil engineering. Notwithstanding the recent progress, the unsatisfactory mechanical properties and problematic long-term stability in the alkali environment remain daunting challenges toward their large-scale practicability. In this study, we address such limitations by a dual modification method, in which first ethyl cellulose (EC) is incorporated into the matrix and then the FRP composite is dipped in a dilute poly(dimethylsiloxane) (PDMS) solution. The FRP composite exhibited enhanced flexural strength by 23.4% and increased flexural modulus by 23.5% compared to those of the pristine basalt fiber-reinforced polymer (BFRP). Such an eminent performance is mainly attributed to the bridging effect of EC. As confirmed by the DMA characterization, the incorporation of EC greatly increased the cross-linking density and improved the thermal stability. Additionally, the FRP composite had a stable performance in the alkali environment tests. Tuning the amount of ethyl cellulose was found to have a profound effect on the mechanical performance and aging behavior in the alkali solution. This study establishes a practical approach to fabricating FRP composites with long-term stability in alkali environments.

Development of load-bearing fiber reinforced plastic (hereinafter referred to as FRP) composite structures in civil engineering, exploited under high temperatures, such as industrial chimneys and gas ducts, requires the knowledge of their long-term behavior under constant and cyclic mechanical and temperature loads. Such conditions mean that the viscoelasticity of FRP should be considered along with the thermal aging effect. This research is devoted to the effects of thermal aging on the viscoelastic behavior of polymers. Two sets of experiments were conducted: creep tensile tests and cyclic heating in a constrained state. The Kelvin-Voigt viscoelasticity model was used to determine the rheological parameters of binder from experimental creep curves. Cyclic heating was used to compare the behavior of normal and thermally aged binders and to evaluate the possibility of temperature stress accumulation. Fourier-transform infrared spectroscopy was used for polymer's structural changes investigation. Both tests showed that non-aged glassed polymer (hereinafter referred to as GP) was prone to viscoelastic behavior, while the thermally aged GP lost viscosity and worked almost perfectly elastic. It was assumed that long heat treatment had caused changes in the inner structure of the GP, reducing the number of weak bonds and increasing the number of elastic ones. Therefore, the results show that the designing of FRP structures, exploited under thermomechanical load, requires using the elastic model while taking into account the properties of FRP after long-term heat treatment.

The detection and evaluation of corrosion defects take on a critical significance to ensure the service safety of steel structures in civil engineering. The quantitative evaluation of corrosion defects has not been well addressed though metal magnetic memory (MMM) testing technology has been investigated in steel corrosion problems. In this study, the Q345qD steel plates were taken as the specimens of MMM testing. Specimens with different corrosion degrees were developed through electrochemical corrosion, and the change laws of the MMM signals and the characteristics of different corrosion specimens were analyzed. A three-dimensional (3D) magnetic charge model of the corrosion area was built based on the magnetic charge theory, such that the change laws of the MMM signal in the corrosion area from the mechanism were explained. The finite element simulation results of the corrosion specimens were well consistent with the experimental and theoretical results. A quantitative evaluation method for corrosion defect depth was proposed in combination with finite element simulation and experimental data. Comparing the experimental data and the inversion data, the relative errors of the determined defect depth h were within 20%, suggesting that the proposed evaluation method is feasible for the quantitative evaluation of steel corrosion depth.

6.25 - Composite Materials and Structures in Civil Engineering

Among technologies used for ground penetrating radar (GPR), ultra-wideband (UWB) is an attractive choice thanks to its ability to provide high data rate transmission and high detection resolution. Nowadays, many such systems are offered in the world market, but their prices are usually very high. In this paper, we present an inexpensive ultra-wideband GPR designed and tested at our Microwave Lab, focusing on design, simulation and measurement of antennas, theoretical and experimental study of the system detection ability for various forms and locations of objects under test. As a result, quite high resolution (less than 1 cm) was obtained that shows promising performance of the system to be used for detection of defects in constructional structures in civil engineering.