The Experts below are selected from a list of 26952 Experts worldwide ranked by ideXlab platform
Richard M Gutkowski - One of the best experts on this subject based on the ideXlab platform.
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Repair of Full-Scale Timber Bridge Chord Members by Shear Spiking
Journal of Bridge Engineering, 2008Co-Authors: Travis A. Burgers, Jeno Balogh, Richard M Gutkowski, Donald W. RadfordAbstract:The addition of vertically oriented shear spikes (fiberglass reinforced polymer rods) was shown to increase the effective stiffness of the stringers of a full-scale timber bridge chord Specimen. Results found from the flexural load testing of a full-scale timber bridge chord Laboratory Specimen are presented. Reinforcement was provided with 19 mm diameter shear spikes bonded to the wood by an epoxy resin. The bridge chord Specimen was intentionally damaged to simulate degradation. Shear spikes were then installed from the top of the member into predrilled holes to provide horizontal shear resistance and to improve the flexural effective stiffness. Results from the testing showed that with the insertion of five sets of shear spikes the average flexural effective stiffness recovered in the four stringers of the chord was 91.6%.
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Laboratory tests of an anisotropic grid timber bridge
Construction and Building Materials, 2007Co-Authors: Richard M Gutkowski, P A Favre, Julius NattererAbstract:Research and development was conducted on a prototype timber bridge technology developed for rural bridge sites. The work included conception, computer modeling, Laboratory load tests of a reduced size Specimen, field construction of a pilot bridge and field load testing. This paper describes the Laboratory load test phase. Three loadings comprised of four concentrated loads simulating a truck wheel pattern were conducted. Results of preliminary analytical simulation work is also described. The Laboratory Specimen demonstrated the structural effectiveness of the concept and led to the final design and implementation of the pilot field bridge. (c) 2005 Elsevier Ltd. All rights reserved.
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Composite Repair of Full-Scale Timber Bridge Chord Members Through the Process of Shear Spiking
2005Co-Authors: Travis A. Burgers, Donald W. Radford, Richard M Gutkowski, Jeno BaloghAbstract:Investigations into the effects of the addition of vertically-oriented shear spikes with fiberglass reinforced polymer rods have shown that the shear spikes increased the effective stiffness of the stringers of a full-scale timber bridge chord Specimen. This was previously found to be true on dimension lumber and medium-sized timber. This report presents the results found from the flexural load testing of a full-scale timber bridge chord Laboratory Specimen. The bridge chord Specimen was intentionally damaged to simulate degradation. Reinforcement was provided with 19 mm (3/4-in.) diameter fiberglass reinforced polymer shear spikes bonded to the wood by an epoxy resin. Shear spikes were installed in pairs vertically from the top of the member into pre-drilled holes to provide horizontal shear resistance and to improve the flexural effective stiffness. Results from the testing showed that with the insertion of five sets of shear spikes an average effective stiffness of 91.6% was recovered in the four stringers of the chord.
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guardrail in posttensioned timber bridge Specimen
Journal of Structural Engineering-asce, 1994Co-Authors: Richard M Gutkowski, P. J. Pellicane, Jean‐francois KalinAbstract:A semiempirical, mathematical model for assessing the load behavior of bridge guardrail systems is described. A full‐scale Laboratory Specimen was represented by a beam supported by coupled, elastic springs. Empirical flexibility coefficients were used to establish the spring constants for the post and deck subassembly of the Specimen. This model was applied to a panelized, longitudinal‐deck bridge Specimen. Laboratory load tests were conducted both without and with posttensioning features incorporated into the Specimen. Longitudinal, transverse and angular loads were separately applied to the Specimen. The model was successful at predicting transverse load‐displacement behavior. A stiffening due to posttensioning was evident. Due to erratic load‐slip behavior of the connection details, the modeling of longitudinal load‐displacement behavior was unsuccessful. The danger of a possible failure of the guardrail post at a low load level was observed under longitudinal loading. Loosening of the post to deck co...
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Guardrail in Posttensioned Timber‐Bridge Specimen
Journal of Structural Engineering-asce, 1994Co-Authors: Richard M Gutkowski, P. J. Pellicane, Jean‐francois KalinAbstract:A semiempirical, mathematical model for assessing the load behavior of bridge guardrail systems is described. A full‐scale Laboratory Specimen was represented by a beam supported by coupled, elastic springs. Empirical flexibility coefficients were used to establish the spring constants for the post and deck subassembly of the Specimen. This model was applied to a panelized, longitudinal‐deck bridge Specimen. Laboratory load tests were conducted both without and with posttensioning features incorporated into the Specimen. Longitudinal, transverse and angular loads were separately applied to the Specimen. The model was successful at predicting transverse load‐displacement behavior. A stiffening due to posttensioning was evident. Due to erratic load‐slip behavior of the connection details, the modeling of longitudinal load‐displacement behavior was unsuccessful. The danger of a possible failure of the guardrail post at a low load level was observed under longitudinal loading. Loosening of the post to deck co...
Jean‐francois Kalin - One of the best experts on this subject based on the ideXlab platform.
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guardrail in posttensioned timber bridge Specimen
Journal of Structural Engineering-asce, 1994Co-Authors: Richard M Gutkowski, P. J. Pellicane, Jean‐francois KalinAbstract:A semiempirical, mathematical model for assessing the load behavior of bridge guardrail systems is described. A full‐scale Laboratory Specimen was represented by a beam supported by coupled, elastic springs. Empirical flexibility coefficients were used to establish the spring constants for the post and deck subassembly of the Specimen. This model was applied to a panelized, longitudinal‐deck bridge Specimen. Laboratory load tests were conducted both without and with posttensioning features incorporated into the Specimen. Longitudinal, transverse and angular loads were separately applied to the Specimen. The model was successful at predicting transverse load‐displacement behavior. A stiffening due to posttensioning was evident. Due to erratic load‐slip behavior of the connection details, the modeling of longitudinal load‐displacement behavior was unsuccessful. The danger of a possible failure of the guardrail post at a low load level was observed under longitudinal loading. Loosening of the post to deck co...
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Guardrail in Posttensioned Timber‐Bridge Specimen
Journal of Structural Engineering-asce, 1994Co-Authors: Richard M Gutkowski, P. J. Pellicane, Jean‐francois KalinAbstract:A semiempirical, mathematical model for assessing the load behavior of bridge guardrail systems is described. A full‐scale Laboratory Specimen was represented by a beam supported by coupled, elastic springs. Empirical flexibility coefficients were used to establish the spring constants for the post and deck subassembly of the Specimen. This model was applied to a panelized, longitudinal‐deck bridge Specimen. Laboratory load tests were conducted both without and with posttensioning features incorporated into the Specimen. Longitudinal, transverse and angular loads were separately applied to the Specimen. The model was successful at predicting transverse load‐displacement behavior. A stiffening due to posttensioning was evident. Due to erratic load‐slip behavior of the connection details, the modeling of longitudinal load‐displacement behavior was unsuccessful. The danger of a possible failure of the guardrail post at a low load level was observed under longitudinal loading. Loosening of the post to deck co...
Julius Natterer - One of the best experts on this subject based on the ideXlab platform.
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Laboratory tests of an anisotropic grid timber bridge
Construction and Building Materials, 2007Co-Authors: Richard M Gutkowski, P A Favre, Julius NattererAbstract:Research and development was conducted on a prototype timber bridge technology developed for rural bridge sites. The work included conception, computer modeling, Laboratory load tests of a reduced size Specimen, field construction of a pilot bridge and field load testing. This paper describes the Laboratory load test phase. Three loadings comprised of four concentrated loads simulating a truck wheel pattern were conducted. Results of preliminary analytical simulation work is also described. The Laboratory Specimen demonstrated the structural effectiveness of the concept and led to the final design and implementation of the pilot field bridge. (c) 2005 Elsevier Ltd. All rights reserved.
Carl L Monismith - One of the best experts on this subject based on the ideXlab platform.
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effects of Laboratory Specimen preparation on aggregate asphalt structure air void content measurement and repetitive simple shear test results
Transportation Research Record, 1994Co-Authors: John T Harvey, Jorge B. Sousa, Kirsten Eriksen, Carl L MonismithAbstract:Effects of Laboratory compaction devices (rolling wheel, gyratory, and kneading) on asphalt aggregate structure is investigated using image analysis of plane sections cut from Specimens. Also investigated are the effects of Specimen surface condition (both as-compacted and cut and cored) on air-void structure, air-void content measurement, and repetitive simple shear test-constant height (RSST-CH) results. Image analysis indicates that gyratory compaction produces less aggregate orientation than rolling wheel compaction, and little or no orientation in aggregates that do not have a flaky shape. Image analysis also reveals that the outer periphery of as-compacted Specimens has a different air-void and aggregate structure than that found in the Specimen interior. Other results from air-void content measurements of gyratory and rolling wheel Specimens at different stages of cutting and coring showed that there is little air-void content gradient in Specimens that have been cored and cut from larger compacted masses. In addition, it was learned that RSST-CH results for as-compacted and cut and cored Specimens cannot be compared because of problems with air-void content measurement and cut and uncut aggregates' different responses to shear stress at the Specimen surface.
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effects of Laboratory asphalt concrete Specimen preparation variables on fatigue and permanent deformation test results using strategic highway research program a 003a proposed testing equipment
Transportation Research Record, 1993Co-Authors: John T Harvey, Carl L MonismithAbstract:A study was carried out to determine the effects of Laboratory Specimen preparation variables on permanent deformation, fatigue, and flexural stiffness performance, as measured with test equipment and methods by a Strategic Highway Research Program contractor. The Specimen preparation variables included in the project were binder type, aggregate type, fines content, air-void content, compaction method, mixing viscosity, and compaction viscosity. Asphalt rubber was included as one of the binders in the experiment. The test methods used were the constant-height repetitive shear test for permanent deformation and the controlled-stress beam apparatus for flexural fatigue and stiffness. The investigation indicates that the variables included in the study affect the test results. Of particular interest were the results showing that (a) compaction method (gyratory, rolling wheel, and kneading compaction were included in the study) is a significant factor in permanent deformation performance; (b) a reduction in fines content of 3% significantly affects both permanent deformation and fatigue performance; and (c) the temperatures at which a mix is mixed and compacted also significantly affect fatigue performance. In addition, the constant-height repetitive shear test results showed asphalt-rubber mixes to be superior to the conventional asphalt mixes at 60 deg C (140 deg F).
Chiaoni Wen - One of the best experts on this subject based on the ideXlab platform.
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reduction in hospital wide clinical Laboratory Specimen identification errors following process interventions a 10 year retrospective observational study
PLOS ONE, 2016Co-Authors: Hsiaochen Ning, Chiani Lin, Daniel Tsunyee Chiu, Yungta Chang, Chiaoni WenAbstract:Background Accurate patient identification and Specimen labeling at the time of collection are crucial steps in the prevention of medical errors, thereby improving patient safety. Methods All patient Specimen identification errors that occurred in the outpatient department (OPD), emergency department (ED), and inpatient department (IPD) of a 3,800-bed academic medical center in Taiwan were documented and analyzed retrospectively from 2005 to 2014. To reduce such errors, the following series of strategies were implemented: a restrictive Specimen acceptance policy for the ED and IPD in 2006; a computer-assisted barcode positive patient identification system for the ED and IPD in 2007 and 2010, and automated sample labeling combined with electronic identification systems introduced to the OPD in 2009. Results Of the 2000345 Specimens collected in 2005, 1023 (0.0511%) were identified as having patient identification errors, compared with 58 errors (0.0015%) among 3761238 Specimens collected in 2014, after serial interventions; this represents a 97% relative reduction. The total number (rate) of institutional identification errors contributed from the ED, IPD, and OPD over a 10-year period were 423 (0.1058%), 556 (0.0587%), and 44 (0.0067%) errors before the interventions, and 3 (0.0007%), 52 (0.0045%) and 3 (0.0001%) after interventions, representing relative 99%, 92% and 98% reductions, respectively. Conclusions Accurate patient identification is a challenge of patient safety in different health settings. The data collected in our study indicate that a restrictive Specimen acceptance policy, computer-generated positive identification systems, and interdisciplinary cooperation can significantly reduce patient identification errors.
