In order to investigate the compression creep of two kinds of high-performance concrete mixtures used for prestressed members in a bridge,an experimental test under laboratory conditions was carried out.Based on the e...In order to investigate the compression creep of two kinds of high-performance concrete mixtures used for prestressed members in a bridge,an experimental test under laboratory conditions was carried out.Based on the experimental results,a power exponent function was used to model the creep degree of these high-performance concretes(HPCs) for structural numerical analysis,and two series parameters of this function for the HPCs were given with the optimum method of evolution program.The experimental data were compared with CEB-FIP 90 and ACI 92 models.Results show that the two code models both overestimate the creep degree of two HPCs,so it is recommended that the power exponent function should be used for the creep analysis of bridge structure.展开更多
The safety of large structures requires adequate foundations, which implies a good knowledge of the geological and geotechnical conditions of the respective ground. In general, that is only possible through engineerin...The safety of large structures requires adequate foundations, which implies a good knowledge of the geological and geotechnical conditions of the respective ground. In general, that is only possible through engineering geological studies which include proper site investigation techniques, adapted to the nature of the ground (rock mass or soil) and to the associated engineering problems. The paper illustrates the studies carried out for the design of the foundations of Ribeiradio 76 m high concrete gravity dam in a difficult rock mass and of Vasco da Gama Bridge, 13 km long, crossing the Tagus River in Lisbon, Portugal, through piles 75 m deep.展开更多
Bridges are the most useful part in the transportation network.Any disruption of the bridge structures may hamper the whole transportation system.In the last recent tsunamis,numerous number of bridges were structurall...Bridges are the most useful part in the transportation network.Any disruption of the bridge structures may hamper the whole transportation system.In the last recent tsunamis,numerous number of bridges were structurally damaged by the tsunami waves.Lack of proper provisions of tsunami forces in the design guidelines also contributes to the augmentations of the damage level.Therefore,proper evaluation of the tsunami forces on the bridge girder should be introduced in the design promptly.In this study,laboratory experiments were carried out to reveal the damage mechanism of the bridge girder by assessing the exerted tsunami forces.Both broken and unbroken waves were considered for the analysis.The results showed that measured forces were larger for broken waves than those of unbroken waves.Maximum force of the broken waves was 4.59 times as large as the hydrostatic pressure.Also,waves reached the peak value more rapidly for larger wave heights than those of smaller ones.Additionally,a girder that is placed at a higher position is much vulnerable to tsunami hazard.展开更多
文摘In order to investigate the compression creep of two kinds of high-performance concrete mixtures used for prestressed members in a bridge,an experimental test under laboratory conditions was carried out.Based on the experimental results,a power exponent function was used to model the creep degree of these high-performance concretes(HPCs) for structural numerical analysis,and two series parameters of this function for the HPCs were given with the optimum method of evolution program.The experimental data were compared with CEB-FIP 90 and ACI 92 models.Results show that the two code models both overestimate the creep degree of two HPCs,so it is recommended that the power exponent function should be used for the creep analysis of bridge structure.
文摘The safety of large structures requires adequate foundations, which implies a good knowledge of the geological and geotechnical conditions of the respective ground. In general, that is only possible through engineering geological studies which include proper site investigation techniques, adapted to the nature of the ground (rock mass or soil) and to the associated engineering problems. The paper illustrates the studies carried out for the design of the foundations of Ribeiradio 76 m high concrete gravity dam in a difficult rock mass and of Vasco da Gama Bridge, 13 km long, crossing the Tagus River in Lisbon, Portugal, through piles 75 m deep.
基金supported by the University of Malaya and Ministry of Education,PPP fund(Grant No.PG 029-2012B)the High Impact Research Fund(Grant Nos.H-16001-00-D000061,J-16002-00-7383000-000000)
文摘Bridges are the most useful part in the transportation network.Any disruption of the bridge structures may hamper the whole transportation system.In the last recent tsunamis,numerous number of bridges were structurally damaged by the tsunami waves.Lack of proper provisions of tsunami forces in the design guidelines also contributes to the augmentations of the damage level.Therefore,proper evaluation of the tsunami forces on the bridge girder should be introduced in the design promptly.In this study,laboratory experiments were carried out to reveal the damage mechanism of the bridge girder by assessing the exerted tsunami forces.Both broken and unbroken waves were considered for the analysis.The results showed that measured forces were larger for broken waves than those of unbroken waves.Maximum force of the broken waves was 4.59 times as large as the hydrostatic pressure.Also,waves reached the peak value more rapidly for larger wave heights than those of smaller ones.Additionally,a girder that is placed at a higher position is much vulnerable to tsunami hazard.
