Stiffening-ribbed-hollow-pipe cast-in place reinforced concrete girderless floor is a new-style hollow girderless floor system. Model experimental researches of simply-supported floor and four-corners bearing floor ha...Stiffening-ribbed-hollow-pipe cast-in place reinforced concrete girderless floor is a new-style hollow girderless floor system. Model experimental researches of simply-supported floor and four-corners bearing floor have been done on this new kind of floor system in this paper. The experiment results show that the floor system has good mechanical property such as high bearing capacity, big rigidity and good tensility. A theoretical method is presented in this paper that the stiffening-ribbed-hollow-pipe girderless floor can be analyzed by being converted equivalently to orthotropic solid slab. It is indicated that the method is correct and reasonable according to the contrast between theoretical calculated results and experimental measured results. The theoretical results coincide with the measured results well.展开更多
A novel distributed tuned liquid damper （DTLD） for reducing vibration in structures is proposed in this paper. The basic working principle of the DTLDs is to fill the empty space inside the pipes or boxes of cast-in...A novel distributed tuned liquid damper （DTLD） for reducing vibration in structures is proposed in this paper. The basic working principle of the DTLDs is to fill the empty space inside the pipes or boxes of cast-in-situ hollow reinforced concrete （RC） floor slabs with water or other liquid. The pipes or boxes then work as a series of small TLDs inside the structure, to increase the damping ratio of the entire structural system. Numerical simulation that accounts for the fluid- structure conpling effect is carried out to evaluate the vibration-reduction efficiency of the DTLDs. The results show that the DTLDs are able to considerably increase the damping of the structure and thus reduce its vibration. An additional benefit is that the DTLDs do not require architectural space to be added to the structure.展开更多
A large-span steel–concrete composite beam with precast hollow core slabs(CBHCSs)is a relatively new floor structure that can be applied to various long-span structures.However,human-induced vibrations may present se...A large-span steel–concrete composite beam with precast hollow core slabs(CBHCSs)is a relatively new floor structure that can be applied to various long-span structures.However,human-induced vibrations may present serviceability issues in such structures.To alleviate vibrations,both the walking forces excited by humans and the associated floor responses must be elucidated.In this study,150 load–time histories of walking,excited by 25 test participants,are obtained using a force measuring plate.The dynamic loading factors and phase angles in the Fourier series functions for one-step walking are determined.Subsequently,walking tests are performed on seven CBHCS specimens to capture the essential dynamic properties of mode shapes,natural frequencies,damping ratios,and acceleration time histories.The CBHCS floor system generally exhibits a high frequency(>10 Hz)and low damping(damping ratio<2%).Sensitivity studies using the finite element method are conducted to investigate the vibration performance of the CBHCS floor system,where the floor thickness,steel beam type,contact time,and human weight are considered.Finally,analytical expressions derived for the fundamental frequency and peak acceleration agree well with the experimental results and are hence proposed for practical use.展开更多
文摘Stiffening-ribbed-hollow-pipe cast-in place reinforced concrete girderless floor is a new-style hollow girderless floor system. Model experimental researches of simply-supported floor and four-corners bearing floor have been done on this new kind of floor system in this paper. The experiment results show that the floor system has good mechanical property such as high bearing capacity, big rigidity and good tensility. A theoretical method is presented in this paper that the stiffening-ribbed-hollow-pipe girderless floor can be analyzed by being converted equivalently to orthotropic solid slab. It is indicated that the method is correct and reasonable according to the contrast between theoretical calculated results and experimental measured results. The theoretical results coincide with the measured results well.
基金Cultivation Fund of the Key Grant Scientifi c and Technical Innovation Project, Ministry of Education of China Under Grant No.704003
文摘A novel distributed tuned liquid damper （DTLD） for reducing vibration in structures is proposed in this paper. The basic working principle of the DTLDs is to fill the empty space inside the pipes or boxes of cast-in-situ hollow reinforced concrete （RC） floor slabs with water or other liquid. The pipes or boxes then work as a series of small TLDs inside the structure, to increase the damping ratio of the entire structural system. Numerical simulation that accounts for the fluid- structure conpling effect is carried out to evaluate the vibration-reduction efficiency of the DTLDs. The results show that the DTLDs are able to considerably increase the damping of the structure and thus reduce its vibration. An additional benefit is that the DTLDs do not require architectural space to be added to the structure.
基金The authors acknowledge the financial support provided by the National Natural Science Foundation of China(51890902 and 51708058).
文摘A large-span steel–concrete composite beam with precast hollow core slabs(CBHCSs)is a relatively new floor structure that can be applied to various long-span structures.However,human-induced vibrations may present serviceability issues in such structures.To alleviate vibrations,both the walking forces excited by humans and the associated floor responses must be elucidated.In this study,150 load–time histories of walking,excited by 25 test participants,are obtained using a force measuring plate.The dynamic loading factors and phase angles in the Fourier series functions for one-step walking are determined.Subsequently,walking tests are performed on seven CBHCS specimens to capture the essential dynamic properties of mode shapes,natural frequencies,damping ratios,and acceleration time histories.The CBHCS floor system generally exhibits a high frequency(>10 Hz)and low damping(damping ratio<2%).Sensitivity studies using the finite element method are conducted to investigate the vibration performance of the CBHCS floor system,where the floor thickness,steel beam type,contact time,and human weight are considered.Finally,analytical expressions derived for the fundamental frequency and peak acceleration agree well with the experimental results and are hence proposed for practical use.
