Zhongguo Ma - Academia.edu (original) (raw)
Professor of Civil/Structural Engineering, University of Tennessee Knoxville
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Papers by Zhongguo Ma
Transportation Research Record, 2005
PCI Journal, 1999
Anchorage zones in prestressed concrete /-beams are designed to accommodate a n chorage hardware ... more Anchorage zones in prestressed concrete /-beams are designed to accommodate a n chorage hardware and to provide adequate space for the reinforcement needed to distribute the highly concentrated post-tensioning force. Based on ana l ytica l and fu ll-scale experimental studies, optimized anchorage zone detai ls have been developed. The proposed standardized anchorage zone is suitab le for use with a post-tensioning tendon size up to 7 5-0.6 in. (7 5 mm) diameter strands. It has a width of 28.5 in. (725 mm), which tapers for a distance of 39.4 in. (7 000 mm) to the standard /-beam web width. Standard welded wire reinforcement is proposed for post-tensioning of up to three 7 5-0.6 in. (7 5 mm) diameter strand tendons. The use of a reduced b lock size can result in a weight reduction of as much as 80 percent compared to the common l y used anchorage block. A detailed example is included to demonstrate app licatio n of the strut-and-tie model to the design of the anchorage zone.
Journal of Bridge Engineering
Journal of Bridge Engineering
Journal of Bridge Engineering
Construction and Building Materials
Journal of Structural Engineering
Construction and Building Materials
Journal of Bridge Engineering
Construction and Building Materials
Expansive concrete filled CFRP tube achieves an effective prestress level. Ultimate load increase... more Expansive concrete filled CFRP tube achieves an effective prestress level. Ultimate load increases with the CFRP layers' increase and eccentricity's decrease. Ultimate lateral deflection increases as the loading eccentricity increases. CCECs show smaller hoop strains than CCUCs under the same conditions. CFRP confined expansive concrete performed well relative to ordinary concrete. a b s t r a c t CFRP confined expansive concrete (CCEC) has shown higher inflection load, intercept load and ultimate load than CFRP confined unexpansive concrete (CCUC) counterparts under axial compression. The aim of this study is to investigate the compression behavior of CFRP confined expansive concrete subjected to eccentric load. Eighteen concrete element specimens have been prepared in this experiment considering the parameters including prestress level, CFRP layer and eccentricity of load. Prestress in concrete and CFRP at 28-day were calculated through the recorded hoop strain on CFRP. It can be observed from the experimental results that the ultimate load increases with the increase of the number of CFRP layers and decreases with the increase of the eccentricity. Experimental and discussion results indicate that CFRP confined expansive concrete show higher intercept loads (average 19.6%), inflection loads (average 20.4%), ultimate loads (average 13.7%) than the corresponding CFRP confined unexpansive concrete under the same testing scenarios. But due to the effect of prestress, relative to unexpansive specimens, the pre-stressed specimens have smaller hoop strains, lateral deflections and curvatures.
Transportation Research Record, 2005
PCI Journal, 1999
Anchorage zones in prestressed concrete /-beams are designed to accommodate a n chorage hardware ... more Anchorage zones in prestressed concrete /-beams are designed to accommodate a n chorage hardware and to provide adequate space for the reinforcement needed to distribute the highly concentrated post-tensioning force. Based on ana l ytica l and fu ll-scale experimental studies, optimized anchorage zone detai ls have been developed. The proposed standardized anchorage zone is suitab le for use with a post-tensioning tendon size up to 7 5-0.6 in. (7 5 mm) diameter strands. It has a width of 28.5 in. (725 mm), which tapers for a distance of 39.4 in. (7 000 mm) to the standard /-beam web width. Standard welded wire reinforcement is proposed for post-tensioning of up to three 7 5-0.6 in. (7 5 mm) diameter strand tendons. The use of a reduced b lock size can result in a weight reduction of as much as 80 percent compared to the common l y used anchorage block. A detailed example is included to demonstrate app licatio n of the strut-and-tie model to the design of the anchorage zone.
Journal of Bridge Engineering
Journal of Bridge Engineering
Journal of Bridge Engineering
Construction and Building Materials
Journal of Structural Engineering
Construction and Building Materials
Journal of Bridge Engineering
Construction and Building Materials
Expansive concrete filled CFRP tube achieves an effective prestress level. Ultimate load increase... more Expansive concrete filled CFRP tube achieves an effective prestress level. Ultimate load increases with the CFRP layers' increase and eccentricity's decrease. Ultimate lateral deflection increases as the loading eccentricity increases. CCECs show smaller hoop strains than CCUCs under the same conditions. CFRP confined expansive concrete performed well relative to ordinary concrete. a b s t r a c t CFRP confined expansive concrete (CCEC) has shown higher inflection load, intercept load and ultimate load than CFRP confined unexpansive concrete (CCUC) counterparts under axial compression. The aim of this study is to investigate the compression behavior of CFRP confined expansive concrete subjected to eccentric load. Eighteen concrete element specimens have been prepared in this experiment considering the parameters including prestress level, CFRP layer and eccentricity of load. Prestress in concrete and CFRP at 28-day were calculated through the recorded hoop strain on CFRP. It can be observed from the experimental results that the ultimate load increases with the increase of the number of CFRP layers and decreases with the increase of the eccentricity. Experimental and discussion results indicate that CFRP confined expansive concrete show higher intercept loads (average 19.6%), inflection loads (average 20.4%), ultimate loads (average 13.7%) than the corresponding CFRP confined unexpansive concrete under the same testing scenarios. But due to the effect of prestress, relative to unexpansive specimens, the pre-stressed specimens have smaller hoop strains, lateral deflections and curvatures.