1,721,152 research outputs found
Selection, production, and testing of scaled reinforced concrete models and their components
No full textLaefer, Debra F/0000-0001-5134-5322; Erkal, Aykut/0000-0002-1679-7937This paper presents considerations and procedures for the selection, production, and testing of small-scale, reinforced concrete frames to maintain geometric and kinematic similitude. To verify the proposed solutions, 1/10th scaled models were subjected to adjacent excavation-induced settlements in 1-gravity, soil-structure experiments. Material scaling strategies were verified by comparing the resultant surface soil settlements with published studies and by comparing the model building response with numerical simulation, as well as the extent of the damage with previously established thresholds. (C) 2016 Published by Elsevier Ltd.National Science FoundationNational Science Foundation (NSF) [CMMI9713854]; UIUC; Schnabel Foundation CompanyThe experimental work, conducted under the supervision of Dr. James H. Long and Edward J. Cording, was funded by National Science Foundation Grant CMMI9713854 and UIUC and realized through the tireless dedication of several dozen undergraduates. The Schnabel Laboratory was made possible through generous funding by the Schnabel Foundation Company, donated technical assistance of Mr. Keith Brandau of Frauenhoffer Associates, and institutional leadership from Dr. Tony Graziano and David Daniels of UIUC
Soundless chemical demolition agents performance under cold and cool temperatures in concrete and masonry structures
No full textThere are several commonly used traditional demolition methods such asjackhammers, explosives, controlled blasting and diamond wire saws.Unfortunately, these traditional methods produce high levels of noise, vibration anddust. As such, demolition of rocks, existing concrete structures, historic structuresand densely populated areas always raises concerns. In such cases, SoundlessChemical Demolition Agents (SCDAs) offer a reliable alternative. This PhD thesisfocuses on SCDA performance under cold and cool temperatures by means of foursets of experimental work. Across these tests, the relationship between ambienttemperature, heat of hydration, volumetric expansion, calcium hydroxide Ca(OH)2and calcium carbonate (CaCO3) were monitored under different ambienttemperatures and conditions. As a part of these tests, the impact of the thermaltransfer likely to be present during concrete demolition and its effect on thehydration heat development and pressure generation was considered. Resultsindicate that higher ambient temperature results in higher heat of hydration andhigher expansive pressure development. The relationship between ambienttemperature, volumetric expansion and calcium hydroxide Ca(OH)2 generation wasalso investigated. In the last part of this thesis, SCDAs were used for selective andpartial removal of masonry units. The experimental results show that partialremoval was successful, although selective targeted removal of individual masonryunits removal was not possible by hand, despite significant cracking in the area.Check date.issued and date.embargo: Flexible delayed release embargo added by autho
Spatial data storage and processing strategies for urban laser scanning
No full textToday, laser scanning technology offers unprecedented data for a wide range of crucial analysis of the complex urban environment. However, the significant data burden and the data complexity have remained significant impediment to effective data exploration. The latest commercial laser scanning instrument is capable of conducting in excess of a million spatial and temporal measurements every second. Since laser scanning projects are typically deployed over large geographical areas, this results in large and complex datasets that require sophisticated data modelling and indexing strategies to ensure efficient data accessibility. Additionally, such voluminous laser scanning data frequently requires strategic processing strategies to extract semantic information so that they can serve specific demands in various application domains.Given the large and rapidly growing quantities of laser scanning data being produced, many existing laser scanning data handling solutions are quickly losing their viability, thereby requiring new improvements in the field. The first part of this thesis proposes two innovative LiDAR data handling solutions aimed at scalability, data retrieval speed and advanced functionalities. They include a system for discrete point data, called UMG_PC (Urban Modelling Group - Point Cloud), and another data system for full waveform LiDAR data, called UMG_FW (Urban Modelling Group - Full Waveform). Both LiDAR data handling systems are based on a novel hybrid spatial indexing strategy, which combines a two-dimensional indexing structure at a global level and multiple, in-memory three-dimensional indices at a local level so that the entire index adapts to the typical spatial distribution of urban LiDAR datasets. The point cloud database system is highly scalable while simultaneously offering better data retrieval speed compared to the traditional one level indexing solution. In addition, it is also capable of supporting advanced queries, including incremental nearest neighbour search and planar segment selection, which was not previously available in a spatial database. Furthermore, the full waveform data management system, with its capability of supporting spatial and spatial-temporal pulse data retrievals, represents a breakthrough in storage and indexing of full waveform LiDAR data.The second part of the thesis devises several improvements to two challenging topics in LiDAR processing towards automatic urban modelling. The first is the integration of an octree spatial structure into a region growing segmentation algorithm, which vastly accelerates the data processing speed without significantly compromising the output accuracy. In that work, the octree plays multiple roles: (1) data simplification, (2) neighbourhood identification, and (3) data indexing. Additionally, a workflow is proposed for detection of complex urban road networks from a dense aerial point cloud fused with high-resolution aerial imagery data. This includes a novel algorithm that exploits the high variance of slope and height of the point data in the direction orthogonal to the road boundaries. That final study demonstrates an end-to-end LiDAR processing workflow making use of data residing in a database. That study reveals emerging opportunities for detection of small objects from airborne laser data
Planning Infrastructure Documentation with Aerial Laser Scanning
Get PDFIABSE Conference, Rotterdam, The Netherlands, 6-8 May 2013Worldwide there are millions of bridges and overpasses that need documentation, inspection, and maintenance. Aerial laser scanning has the potential to assist in this process not only through the initial documentation stage but through the automated creation of three-dimensional, computational models and a further integration of that data with the surrounding environment. This paper outlines the difficulties related to effective vertical data capture for major infrastructure elements and recommends specific approaches towards a geometric optimization of this problem. Results of the current level of viability using a test area in Dublin, Ireland are included based on the application of this optimization.European Research Counci
Solutions for Model-Scale, Tied-Back Anchors and Sheet Pile Walls
Get PDFGeo-Congress 2014: Geo-Characterization and Modelling for Sustainability, Atlanta, Georgia, 23 - 26 February 2014Scaled laboratory experiments are faster and less expensive than full-scale ones and do not rely upon possible uncertainties in the constitutive models necessary for numerical modeling. However, for 1-gravity (1g) pseudo-static testing, the main problem is obtaining geometrically appropriate materials whose strength and stiffness are sufficiently reduced compared with those of the prototype. Constructability can also pose major challenges. This paper introduces manufacturing, assembly, monitoring, and testing for tied-back anchors with a sheet pile wall for 1g testing.Schnabel Foundation CompanyNational Science FoundationUIU
Gender disparity in engineering as a function of physics enrollment and its implications for civil engineering
Get PDFDespite tremendous advances by women in the natural and applied sciences, where in selective fields women have surpassed men in the earning of doctoral degrees for more nearly 20 years, female enrollment levels in engineering continue to be a fraction of male enrollment. Gender disparities of more than 60% persist in undergraduate engineering enrollments and have recently worsened. As American female Civil Engineering enrollment has been flat for over 25 years, efforts must be taken to understand this stasis. This paper focuses primarily on secondary education preparation in terms of both attitudes towards and enrollment levels in pre-engineering courses such as calculus, chemistry, and physics. Additional consideration is given to enrollment and achievement in advanced placement courses, as reflected in national examination rates. This paper concludes that secondary school participation and achievement in physics courses is a critical differential factor as one explanatory element of female engineering enrollment levels and provides specific recommendations as to how to increase interest, enrollment, and achievement in physics, including the segregation of entry-level engineering courses based on previous experience.Not applicableNeed to link to publisher version - http://cedb.asce.org/cgi/WWWdisplay.cgi?172722. au ti ke- 100721 R
Vernacular structures
Get PDFPresented at the Fourth International Seminar on Structural Analysis of Historical Constructions (SAHC) : Possibilities of Numerical and Experimental Techniques. November 10-13, 2004, Padova, ItalyDespite being considered one of many seventeenth century American wall insulation systems, brick nogging emerges as a prevalent construction type throughout all of original colonies. Used in both framed and hewn-log structural systems, brick nogging is most typically found beneath clapboard siding. Because clapboard ultimately becomes a style in its own right, the presence of brick nogging beneath such clapboards becomes an unexpected complication for modern preservation and intervention efforts. The technique of placing fired and unfired bricks mortar, clayed, and dry laid, although poorly documented extends well into the nineteenth century increasing the anticipated weight of the structure by ten percent. Similarly, the presence of brick nogging substantially changes the structure’s wall stiffness. Identifying clapboard covered, brick nogging
structures is not straightforward as their emergence was influenced by historical, fiscal and social factors in addition to engineering considerations.Not applicableConference website n/a. Note from publisher - "Please be informed that permission is granted, provided that, as you are planning to do, the original publication is clearly cited." DG 05/07/10 au ti ke SB. 21/7/1
Performance expectations of early 20th century urban American building foundations
No full textPresented at GeoCongress 2008 : Geosustainability and Geohazard Mitigation, March 9-12, 2008, New Orleans, LouisianaFoundation reuse is a tricky business at the best of times. For structures predating the mid-20th century, the challenge is exacerbated by the presence of a variety of foundation types, techniques, and materials no longer in current usage, such as lime based mortar. Accordingly, the modern engineer is presented with the difficulty of making decisions about assessment and intervention strategies for construction systems, geometries, and methods for which there is no applicable current building code or easily accessible textbook. As foundation reuse, particulary of early 20th century urban buildings, gains in popularity, accessing such information will only gain in criticality. This paper was designed to help amalgamate such information and provide upper limits regarding perfomance expectations of such foundations based on early 1900s’ building codes, practices, and testing data, with a typical upperbound of 10MPa in lime.Science Foundation IrelandConference website - http://content.asce.org/conferences/geocongress2008/. Need to link to publisher version - http://cedb.asce.org/cgi/WWWdisplay.cgi?162238. DG 01/07/10
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Vernacular structures
No full textPresented at the Fourth International Seminar on Structural Analysis of Historical Constructions (SAHC) : Possibilities of Numerical and Experimental Techniques. November 10-13, 2004, Padova, ItalyDespite being considered one of many seventeenth century American wall insulation systems, brick nogging emerges as a prevalent construction type throughout all of original colonies. Used in both framed and hewn-log structural systems, brick nogging is most typically found beneath clapboard siding. Because clapboard ultimately becomes a style in its own right, the presence of brick nogging beneath such clapboards becomes an unexpected complication for modern preservation and intervention efforts. The technique of placing fired and unfired bricks mortar, clayed, and dry laid, although poorly documented extends well into the nineteenth century increasing the anticipated weight of the structure by ten percent. Similarly, the presence of brick nogging substantially changes the structure’s wall stiffness. Identifying clapboard covered, brick nogging
structures is not straightforward as their emergence was influenced by historical, fiscal and social factors in addition to engineering considerations.Not applicableConference website n/a. Note from publisher - "Please be informed that permission is granted, provided that, as you are planning to do, the original publication is clearly cited." DG 05/07/10 au ti ke SB. 21/7/1
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