Blocking rockfalls directly by reinforced concrete(RC) flat sheds with thick sand cushions is an outdated method. Such conventional sheds typically accumulate rock heavily, and become progressively damaged and are dif...Blocking rockfalls directly by reinforced concrete(RC) flat sheds with thick sand cushions is an outdated method. Such conventional sheds typically accumulate rock heavily, and become progressively damaged and are difficult to repair, and are very costly. To address these problems, we propose a new structure called a Graded Dissipating Inclined Steel Rock(GDISR) shed that utilizes the graded energy dissipation method. Here, we study the dynamic response of the GDISR shed with model test and numerical simulation, and give its optimization design combining with a practical engineering case. Our results show that the optimized modular E-block and corrugated steel tube can deform to sufficiently absorb the energy of different impact intensities. This efficiently and economically provides GDISR sheds with two security lines. Compared with conventional RC sheds, GDISR sheds with optimal incline have a more efficient anti-impact function, are faster and easier to repair, and are much simpler and cheaper to build.展开更多
The rectangle core plate of all-steel buckling-restrained braces(BRBs) usually exhibit obvious local buckling, due to the lack of longitudinal restraint from the encasing tube. To eliminate the undesirable effects, a ...The rectangle core plate of all-steel buckling-restrained braces(BRBs) usually exhibit obvious local buckling, due to the lack of longitudinal restraint from the encasing tube. To eliminate the undesirable effects, a novel steel BRB is proposed. In this new-type steel BRB, two T-shaped steels are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or mortar. Meanwhile, the ingot-iron material with low yielding strength and high elongation is applied to the steel core to study the mechanical properties of steel BRBs. To validate the theoretical requirements for the width-to-thickness ratio of the steel core and the thickness of angle steel, quasi-static tests of eight specimens were conducted. The tests focused on the energy dissipation capacity and failure modes of the proposed steel BRBs. Nonlinear finite element analysis was also carried out to validate the experimental results. Both the aforementioned results imply that appropriately designed steel BRBs can meet the performance requirements for BRB components.展开更多
Typical all-steel buckling-restrained braces(BRBs)usually exhibit obvious local buckling,which is attributed to the lack of longitudinal restraint to the rectangle core plate.To address this issue,all-steel BRBs are p...Typical all-steel buckling-restrained braces(BRBs)usually exhibit obvious local buckling,which is attributed to the lack of longitudinal restraint to the rectangle core plate.To address this issue,all-steel BRBs are proposed,in which two T-shaped steel plates are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or mortar.In order to investigate the factors that characterize the hysterical responses of this device,different finite element(FE)models are developed for the specific context.The FE models are developed based on nonlinear finite element software,which incorporate continuum(shell or brick)elements,large displacement,and deformation formulations.In these FE models,two different steel constitutive models are adopted to precisely reproduce the cyclic response of the BRB component.Meanwhile,comparisons between the numerical and experimental results are conducted to validate the effectiveness and accuracy of the robust FE model.The agreements between experimental observations and numerical predictions demonstrate that the FE method could be utilized for in depth parametric analysis.Furthermore,BRBs with detailed configurations can provide excellent hysteretic behavior and seismic performance through the optimal design process.展开更多
基金supported by the National Key Basic Research Program of China(2016YFB0201003)the National Natural Science Foundation of China(41672356)the 135 Strategic Program of the Institute of Mountain Hazards and Environment,CAS(SDS-135-1704)
文摘Blocking rockfalls directly by reinforced concrete(RC) flat sheds with thick sand cushions is an outdated method. Such conventional sheds typically accumulate rock heavily, and become progressively damaged and are difficult to repair, and are very costly. To address these problems, we propose a new structure called a Graded Dissipating Inclined Steel Rock(GDISR) shed that utilizes the graded energy dissipation method. Here, we study the dynamic response of the GDISR shed with model test and numerical simulation, and give its optimization design combining with a practical engineering case. Our results show that the optimized modular E-block and corrugated steel tube can deform to sufficiently absorb the energy of different impact intensities. This efficiently and economically provides GDISR sheds with two security lines. Compared with conventional RC sheds, GDISR sheds with optimal incline have a more efficient anti-impact function, are faster and easier to repair, and are much simpler and cheaper to build.
基金Supported by:Basic Research Foundation of Institute of Engineering Mechanics,CEA under Grant No.2017A01the Earthquake Scientific Research Funds Program under Grant No.201508023
文摘The rectangle core plate of all-steel buckling-restrained braces(BRBs) usually exhibit obvious local buckling, due to the lack of longitudinal restraint from the encasing tube. To eliminate the undesirable effects, a novel steel BRB is proposed. In this new-type steel BRB, two T-shaped steels are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or mortar. Meanwhile, the ingot-iron material with low yielding strength and high elongation is applied to the steel core to study the mechanical properties of steel BRBs. To validate the theoretical requirements for the width-to-thickness ratio of the steel core and the thickness of angle steel, quasi-static tests of eight specimens were conducted. The tests focused on the energy dissipation capacity and failure modes of the proposed steel BRBs. Nonlinear finite element analysis was also carried out to validate the experimental results. Both the aforementioned results imply that appropriately designed steel BRBs can meet the performance requirements for BRB components.
基金Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant No.2019A03。
文摘Typical all-steel buckling-restrained braces(BRBs)usually exhibit obvious local buckling,which is attributed to the lack of longitudinal restraint to the rectangle core plate.To address this issue,all-steel BRBs are proposed,in which two T-shaped steel plates are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or mortar.In order to investigate the factors that characterize the hysterical responses of this device,different finite element(FE)models are developed for the specific context.The FE models are developed based on nonlinear finite element software,which incorporate continuum(shell or brick)elements,large displacement,and deformation formulations.In these FE models,two different steel constitutive models are adopted to precisely reproduce the cyclic response of the BRB component.Meanwhile,comparisons between the numerical and experimental results are conducted to validate the effectiveness and accuracy of the robust FE model.The agreements between experimental observations and numerical predictions demonstrate that the FE method could be utilized for in depth parametric analysis.Furthermore,BRBs with detailed configurations can provide excellent hysteretic behavior and seismic performance through the optimal design process.
