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International Concrete Abstracts Portal

Showing 1-5 of 11 Abstracts search results

Document: 

SP292-09

Date: 

October 2, 2013

Author(s):

Helmut Wenzel, Robert Veit-Egerer and Monika Widmann

Publication:

Symposium Papers

Volume:

292

Abstract:

The current publication focuses on Integral Life Cycle Analysis merging major components of structural assessment (Visual Inspection, Design Code Considerations and Structural Health Monitoring). The paper represents the authors contribution to the US Long-Term Bridge Performance Program based on an individual case study (reference bridge NEW JERSEY) in 2010. The developed methodology for the management of infrastructure is based on 20 years of experience in structural assessment – linking research and consulting purposes by means of a constant and synergetic approach. The following major aspects are covered: • The determination/estimation of the DESIGN LIFE OF THE INVESTIGATED structures • The determination/estimation of the RESIDUAL LIFE OF THE INVESTIGATED structures • Assessment criteria whether the REAL DEGRADATION PROCESS corresponds with the assumed and applied life cycle model in order to take corrective measures in cases of accelerated ageing • MAINTENANCE INSTRUCTIONS to guarantee the original design life and operability The elaborated approach delivers all necessary measures to guarantee the functional capability of structures during the overall design life, considering even individual characteristics of each structural member. The chosen categorisation reflects the common composition of available inspection reports making it coherent with civil engineering practice all over the world.

DOI:

10.14359/51686291


Document: 

SP292-06

Date: 

October 2, 2013

Author(s):

Yoon-Si Lee, Brent Phares, Terry Wipf and Faris Malhas

Publication:

Symposium Papers

Volume:

292

Abstract:

This paper presents an autonomous SHM system that was developed to detect and identify overload occurrence, and changes in structural behavior for bridges primarily on the secondary road system. SHM has gained much attention over the past 10 years. However, for the most part the primary focus has been on deployments on Interstate and other primary highway bridges. It is possible, however, for local systems engineers to reap similar benefits as long as cost, scope, and required staff technical abilities fit within local systems restraints. The SHM system utilizes a new approach to identifying and extracting useful information from large data files. By reducing the large data files into smaller packets of the most relevant information, data processing is greatly relieved, reliable analytical results are quickly achieved, and the long-term structural performance of secondary road system bridges can be presented to owners in a clear format that is more easily understood and utilized. Appropriate data processing and evaluation procedures allows the amount of saved data to be significantly reduced to less than 0.1% of collected data and for the data to be “comfortable” to use by local systems engineers. In addition, this system showcases application and testing of traditional strain gage sensors, installation of the system components, and wireless communication from the bridge site to the owner for monitoring updates. The installation of the strain gages and cabling required no training or special equipment other than safety and normal access equipment. Excluding the communication and power equipment and research and development costs, the system can be implemented at the cost of $10,000 to $15,000 depending on the number of sensors used.

DOI:

10.14359/51686288


Document: 

SP292-04

Date: 

October 2, 2013

Author(s):

Daniele Inaudi and Riccardo Belli

Publication:

Symposium Papers

Volume:

292

Abstract:

Distributed fiber optic technology offers the capability to measure strain and deformation at thousands of points along a single fiber up to tens of kilometers. This is of particular interest for the monitoring in geotechnical structures where it allows the detection and localization of ground movements. Fiber optic sensing system offers the ability to detect and localize deformation induced by geological assessments, allowing the monitoring of kilometers with a single instrument and localization of the event with a precision better than 1 meter. To improve and optimize the thermal, mechanical and water transport properties of the sensing cable, the optical fiber sensor can be integrated in different types of geotextiles. Geotextile may, for example, be used to increase the strain-transfer surface, to route leaking water to the sensing cable or to protect the cable from damage. Another civil engineering application of textiles is in the reinforcement of structures with composites. In this case the textile is used to reinforce ageing structures, such as masonry walls in seismic regions, corroded concrete columns and beams or other structural elements that require an increase in load-bearing capacity. However, the retrofitting by means of composites covers the original structure and therefore restricts the possibility to visually inspect it. Furthermore, the bonding between the composites and the original structure plays a major role in the effectiveness of such repairs and it must be guaranteed over time. To address such uncertainties, optical fiber sensors are embedded in the textile and become integral part of the composite material when the resin cures. Once in place, those sensors provide information about the strain and deformation of the composite and of the underlying structure. This paper presents several designs of smart textiles and their field applications.

DOI:

10.14359/51686286


Document: 

SP292-02

Date: 

October 2, 2013

Author(s):

Branko Glisic

Publication:

Symposium Papers

Volume:

292

Abstract:

Needs for structural health monitoring in the last decades were rapidly increasing, and these needs stimulated developments of various sensing technologies. Distributed optical fiber sensing technologies have reached market maturity and opened new possibilities in structural health monitoring. Distributed strain sensor (sensing cable) is sensitive at each point of its length to strain changes and cracks. Such a sensor practically monitors one-dimensional strain field and can be installed over the entire length of the monitored structural members, and therefore provides for integrity monitoring, i.e. for direct detection and characterization of local strain changes generated by damage (including recognition, localization, and quantification or rating). The aim of this paper is to help researchers and practitioners to get familiar with distributed sensing technologies, to understand the meaning of the distributed measurement, and to learn on best performances and limitations of these technologies. Hence, this paper briefly presents light scattering as the main physical principle behind technologies, explains the spatial resolution as the important feature for interpretation of measurements, compares performances of various distributed technologies found in the market, and introduces the concept of integrity monitoring applicable to various concrete structures. Two illustrative examples are presented, including applications to pipeline and bridge.

DOI:

10.14359/51686284


Document: 

SP292

Date: 

October 2, 2013

Author(s):

Editors: Branko Glisic, Nakin Suksawang and Faris Malhas / Sponsored by Committee 444

Publication:

Symposium Papers

Volume:

292

Abstract:

Structural health monitoring (SHM) is a process aimed at providing accurate and timely information concerning structural health condition and performance. The information obtained from monitoring is generally used to plan and design maintenance activities, increase the safety, verify hypotheses, reduce uncertainty, and widen the knowledge concerning the structure being monitored. The technologies used to perform the SHM are continuously developing, and researchers and practitioners are not always aware of their market maturity, performances, and applicability. The papers included in this CD, 1) Identify the state-of-the-art SHM technologies, including their performances, applications, and market maturity; 2) Generalize the use of SHM technologies for various classes of problems and structures; 3) Examine how the SHM technologies can be used in evaluation of the current conditions and performances of concrete structures; and 4) Analyze the benefits of SHM technologies regarding the preservation and safety of concrete structures and long-term management activities in general. This CD consists of 10 papers that were presented at a technical session sponsored by ACI Committee 444 at the ACI Convention in Cincinnati, Ohio in October 2011. Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-292

DOI:

10.14359/51685957


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