A rigid mode of long-span cantilevered roof was tested in wind tunnel. By analyzing the relation between wind angle and wind pressure coefficient and the relation between wind angle and wind shape factor, we found tha...A rigid mode of long-span cantilevered roof was tested in wind tunnel. By analyzing the relation between wind angle and wind pressure coefficient and the relation between wind angle and wind shape factor, we found that 90° is the most disadvantageous wind angle. Furthermore, the fluctuation of wind pressure at the windward edge was reflected by power spectrum density （PSD） and coherence function. The correlation coefficients of measuring points on outer and inner surfaces verifys that the largest lift force was produced at 90°.展开更多
Full-scale measurements are regarded as the most reliable method to evaluate wind effects on large buildings and structures. Some selected results are presented in this paper from the full-scale measurement of wind ef...Full-scale measurements are regarded as the most reliable method to evaluate wind effects on large buildings and structures. Some selected results are presented in this paper from the full-scale measurement of wind effects on a long-span steel roof structure during the passage of Typhoon Fanapi. Some fi eld data, including wind speed and direction, acceleration responses, etc., were continuously and simultaneously recorded during the passage of the typhoon. Comprehensive analysis of the measured data is conducted to evaluate the typhoon-generated wind characteristics and its effects on a long-span steel roof. The fi rst four natural frequencies and their vibration mode shapes of the Guangzhou International Sports Arena(GISA) roof are evaluated by the stochastic subspace identifi cation(SSI) method and comparisons with those from fi nite element(FE) analysis are made. Meanwhile, damping ratios of the roof are also identifi ed by the SSI method and compared with those identifi ed by the random decrement method; the amplitude-dependent damping behaviors are also discussed. The fullscale measurement results are further compared with the corresponding wind tunnel test results to evaluate its reliability. The results obtained from this study are valuable for academic and professional engineers involved in the design of large-span roof structures.展开更多
Traditional explosives have characteristics of high risk,large vibration,and poor directional fracturing.Consequently,an instantaneous expander with a single crack surface(IESCS),which is a novel nonexplosive directio...Traditional explosives have characteristics of high risk,large vibration,and poor directional fracturing.Consequently,an instantaneous expander with a single crack surface(IESCS),which is a novel nonexplosive directional rock-breaking technique,has been developed.The directional roof-cutting mechanism of the IESCS method,driven by high-pressure gas,was theoretically analyzed.Laboratory experiments and numerical simulations proved the directional slitting effect of the IESCS method to be excellent.Compared with shaped-charge blasting,the charge of IESCS was reduced by 8.9%,but the crack rate increased by 9%in field tests.After IESCS pre-splitting,the roof directionally collapsed along the cutting line,and the gangue filled the goaf.Moreover,the directional roof cutting by the IESCS could decrease roadway stress.The average pressure of hydraulic supports on the cutting side of the roof was 31%lower than that on the non-cutting side of the roof after pre-splitting.After the self-formed roadway constructed by the IESCS was stabilized,the final relative displacement of the roof and floor was 157.3 mm,meeting the required standard of the next working face.Thus,the IESCS was effectively applied to directional roof pre-splitting.The results demonstrate the promising potential of IESCS in the mining and geotechnical fields.展开更多
The analysis of wind load characteristics of gas-ribbed film structure plays an important role in the performance of the long-span membrane structure.This paper mainly researches on the long-span rib membrane structur...The analysis of wind load characteristics of gas-ribbed film structure plays an important role in the performance of the long-span membrane structure.This paper mainly researches on the long-span rib membrane structure.Surface wind pressure of the membrane structure is calculated by fluent,the distribution of force and surface pressure of the membrane structure under different angles and wind speeds is obtained.The worst working condition of the wind approach angle is 60°.Maximum force angle is positively correlated with windward angle and the length of structure.展开更多
文摘A rigid mode of long-span cantilevered roof was tested in wind tunnel. By analyzing the relation between wind angle and wind pressure coefficient and the relation between wind angle and wind shape factor, we found that 90° is the most disadvantageous wind angle. Furthermore, the fluctuation of wind pressure at the windward edge was reflected by power spectrum density （PSD） and coherence function. The correlation coefficients of measuring points on outer and inner surfaces verifys that the largest lift force was produced at 90°.
基金National Natural Science Foundation of China under Grant Nos.51222801 and 51378134Yangcheng Scholarship in Guangzhou Municipal Universities under Project No.12A004Sthe Research Funding for Ph.D Programme in Higher Education Universities under Project No.20124410110005
文摘Full-scale measurements are regarded as the most reliable method to evaluate wind effects on large buildings and structures. Some selected results are presented in this paper from the full-scale measurement of wind effects on a long-span steel roof structure during the passage of Typhoon Fanapi. Some fi eld data, including wind speed and direction, acceleration responses, etc., were continuously and simultaneously recorded during the passage of the typhoon. Comprehensive analysis of the measured data is conducted to evaluate the typhoon-generated wind characteristics and its effects on a long-span steel roof. The fi rst four natural frequencies and their vibration mode shapes of the Guangzhou International Sports Arena(GISA) roof are evaluated by the stochastic subspace identifi cation(SSI) method and comparisons with those from fi nite element(FE) analysis are made. Meanwhile, damping ratios of the roof are also identifi ed by the SSI method and compared with those identifi ed by the random decrement method; the amplitude-dependent damping behaviors are also discussed. The fullscale measurement results are further compared with the corresponding wind tunnel test results to evaluate its reliability. The results obtained from this study are valuable for academic and professional engineers involved in the design of large-span roof structures.
基金This work was supported by the National Key Research and Development Program of China(No.2016YFC0600901)the National Natural Science Foundation of China(No.41941018)the Postgraduate Research&Practice Innovation Program of Jiangsu Province of China(No.KYCX21_2368).
文摘Traditional explosives have characteristics of high risk,large vibration,and poor directional fracturing.Consequently,an instantaneous expander with a single crack surface(IESCS),which is a novel nonexplosive directional rock-breaking technique,has been developed.The directional roof-cutting mechanism of the IESCS method,driven by high-pressure gas,was theoretically analyzed.Laboratory experiments and numerical simulations proved the directional slitting effect of the IESCS method to be excellent.Compared with shaped-charge blasting,the charge of IESCS was reduced by 8.9%,but the crack rate increased by 9%in field tests.After IESCS pre-splitting,the roof directionally collapsed along the cutting line,and the gangue filled the goaf.Moreover,the directional roof cutting by the IESCS could decrease roadway stress.The average pressure of hydraulic supports on the cutting side of the roof was 31%lower than that on the non-cutting side of the roof after pre-splitting.After the self-formed roadway constructed by the IESCS was stabilized,the final relative displacement of the roof and floor was 157.3 mm,meeting the required standard of the next working face.Thus,the IESCS was effectively applied to directional roof pre-splitting.The results demonstrate the promising potential of IESCS in the mining and geotechnical fields.
文摘The analysis of wind load characteristics of gas-ribbed film structure plays an important role in the performance of the long-span membrane structure.This paper mainly researches on the long-span rib membrane structure.Surface wind pressure of the membrane structure is calculated by fluent,the distribution of force and surface pressure of the membrane structure under different angles and wind speeds is obtained.The worst working condition of the wind approach angle is 60°.Maximum force angle is positively correlated with windward angle and the length of structure.
