SynerCrete’18: interdisciplinary approaches for cement-based materials and structural concrete: synergizing expertise and bridging scales of space and time, vol. 2

info:eu-repo/semantics/publishedVersio

Development, Evaluation and Implementation of Sensor Techniques for Bridges Critical to the National Transportation System

The evolution of structural materials and sensor technology has impacted the bridge industry by improving the robustness of the highway network and providing behavior based condition assessments. During the last decades, conventional materials have been supplemented with state-of-the-art materials (e.g., carbon and fiber based, ultra-high performance concrete, etc.). The evolution of smart or intelligent structures by incorporating systems to quantify performance will continue to revolutionize the bridge industry. While laboratory and field applications have indicated that smart materials are appropriate for bridge applications, additional investigations regarding sensor installation, deployment and data reduction are still needed. The work described herein is a collection of field and laboratory tests in which sensors were applied to verify structural and material behavior and develop smart members for integration as part of a structural health monitoring system for bridge superstructures. Three projects are presented in which new materials and unique structures were evaluated using specialized sensors and monitoring techniques. Two basket-handle arch pedestrian bridges with high-strength steel hanger rods supporting a pre-cast, post-tensioned concrete panel deck system were monitored to prevent deck cracks in the vicinity of the hanger rods. Fiber optic sensors and externally mounted accelerometers were attached to the hanger rods to indirectly determine the tensile forces during incremental construction stages and in service conditions. For the second project, a three-span prestressed concrete (PC) girder, composite deck bridge was monitored and evaluated. One end span consisted of composite FRP deck panels and was compared to the opposite cast-in-place reinforced concrete deck end span. Strategically placed transducers measured strain levels on the PC girders and the FRR panels from controlled live and ambient traffic loadings to determine the degree of composite action, load distribution, and maximum in-service strains. A FRP panel temporary bypass bridge was evaluated as a replacement to typical steel temporary bridges as part of the third project. The research focused on the design, fabrication, construction and load testing of this state-of-the-art bridge. This bridge was instrumented with transducers for measuring deflections and loaded with a static truck at pertinent locations to evaluate its performance. A five year research plan was established to develop a conceptual smart timber bridge made of glued laminated (glulam) stringers and a transverse glulam deck. Both stock and custom fiber optic sensor packages were implemented to quantify the structural response. The first of multiple phases of this national five year plan includes the development of an efficient structural health monitoring system and a smart timber bridge field demonstration. To support these goals, two types of FBG sensors packages were developed, the first evaluated the structural strain response and the second isolated the sensor from mechanical strain for detecting deterioration parameters (e.g., moisture content, corrosion, wood deterioration, etc.). Techniques were developed for embedding and attaching the FBG sensor packages to glulam specimens. Small scale specimens were instrumented with the custom FBG sensor packages and tested under a range of temperature and loading conditions to determine sensor viability. A full scale glulam beam was instrumented with similar FBG sensor packages to demonstrate applicability and evaluate performance at service level proportions. From this work, the following contributions in structural bridge monitoring were added to the state-of-the-art: * Application of FBG sensors and accelerometers to monitor the structural behavior of a bridge during construction. * Applied testing of non-traditional FRP deck panels to validate composite action. * Initial development of a smart timber bridge structural health monitoring system. * Development of FBG sensor packages for implementation in glulam members as part of a smart timber bridge

Faculty Publications and Creative Works 2005

Faculty Publications & Creative Works is an annual compendium of scholarly and creative activities of University of New Mexico faculty during the noted calendar year. Published by the Office of the Vice President for Research and Economic Development, it serves to illustrate the robust and active intellectual pursuits conducted by the faculty in support of teaching and research at UNM. In 2005, UNM faculty produced over 1,887 works, including 1,887 scholarly papers and articles, 57 books, 127 book chapters, 58 reviews, 68 creative works and 4 patented works. We are proud of the accomplishments of our faculty which are in part reflected in this book, which illustrates the diversity of intellectual pursuits in support of research and education at the University of New Mexico

Re-surface: the novel use of deployable and actively-bent gridshells as reusable, reconfigurable and intuitive concrete shell formwork

Following a well-documented rise in the popularity of concrete shell application in the 20th century, thin concrete shells have experienced a global decline despite their potential as efficient structures with an economy of material use with aesthetics benefits. This phenomenon is subject to geographically determined socio-economic conditions and competition from other building solutions as a result of technological advancement in alternative construction systems. Importantly, their decline was attributed to limitations inherent to concrete shell formwork and construction methods. Being able to produce efficient shaping did not ensure that this method of construction is most cost efficient as it still remains difficult to construct double curved surfaces. The thesis addresses the limitations associated with past and present concrete shell building by proposing the use of actively-bent gridshells as re-configurable and reusable formwork for concrete shells to be designed and built. The hypothesis uses deployable scissor-jointed actively-bent gridshells as re-configurable and reusable formwork for concrete shell construction. This was developed from a series of Flash research (Benjamin, 2012) as student construction workshops to investigate the design and creation of actively-bent gridshells held between December 2008 and March 2011 in Sheffield. In this study, to understand this new system, scaled models of actively-bent gridshells were used as preliminary design aid. Deployed into three dimensional forms from a flexible flat grid mat, the structures were rigidized by bracing through triangulation restraints. The temporary rigid structure was subsequently enveloped with fabric onto which concrete was applied to create the concrete shell, thus acting as formwork. This formwork was then removed following the curing of the concrete cast to be reused repeatedly, or reconfigured into another concrete shell form. Hence, the thesis draws on the concepts, principles and ideas pertaining to three key architectural technologies: 1. concrete shell, 2. actively-bent gridshells and 3.fabric formwork. The thesis then presents a series of four prototype concrete shells constructed from different materials spanning between 1.3 meters and 2.45 meters in the workshops at the University of Edinburgh built between August 2014 and September 2015. For each experimental construction, the process of gridshell construction, fabric formwork preparation, concrete casting, gridshell formwork decentring and different design elements of openings, edges and anchorage abutments were analysed and discussed under the themes of construction, architectural tectonics and structure. The tectonic of process and material is understood and discussed based on the idea of stereogeneity (Manelius, 2012). Specifically, the relationship between gridshell as formwork and the concreting process was studied, analysed and assimilated in concrete shells built with progressive sophistication and elegance, culminating in a doubly-curved concrete shell that demonstrated both synclastic and anticlastic geometries, with further abutment simplification, edge leaning and physical openings incorporation. The study concludes with a physical concrete shell model formed by applying concrete onto fabric formwork to cover the Weald and Downland Jerwood gridshell. In the 1:20 scaled model, the proposed method is speculatively applied onto fabric stretched between pre-determined curvatures of the as-built gridshell. This formwork was subsequently removed for reuse, re-deployed and reconfigured. Using finite element analysis, the structural behaviour of the gridshell made of glass-fibre reinforced tubes and structural characteristics of the resultant concrete shell was checked. The interaction between the three technologies are discussed architectonically and structurally to inform guidelines for potential life-scale application. The thesis evidences the feasibility of the proposed system. It re-purposes a scaled model of a deployable gridshell as a physical modelling tool to facilitate concrete shell design, for both pure compression shells and "improper" shells, demonstrating its adaptability. It also promotes and reinvigorates concrete shells as possible architectural systems serving to instigate future research to revive concrete shell construction as an intelligent and intuitive way of creating structures with material economy, structural efficiency and visual elegance

International Conference on Civil Infrastructure and Construction (CIC 2020)

This is the proceedings of the CIC 2020 Conference, which was held under the patronage of His Excellency Sheikh Khalid bin Khalifa bin Abdulaziz Al Thani in Doha, Qatar from 2 to 5 February 2020. The goal of the conference was to provide a platform to discuss next-generation infrastructure and its construction among key players such as researchers, industry professionals and leaders, local government agencies, clients, construction contractors and policymakers. The conference gathered industry and academia to disseminate their research and field experiences in multiple areas of civil engineering. It was also a unique opportunity for companies and organizations to show the most recent advances in the field of civil infrastructure and construction. The conference covered a wide range of timely topics that address the needs of the construction industry all over the world and particularly in Qatar. All papers were peer reviewed by experts in their field and edited for publication. The conference accepted a total number of 127 papers submitted by authors from five different continents under the following four themes: Theme 1: Construction Management and Process Theme 2: Materials and Transportation Engineering Theme 3: Geotechnical, Environmental, and Geo-environmental Engineering Theme 4: Sustainability, Renovation, and Monitoring of Civil InfrastructureThe list of the Sponsors are listed at page 1