Starting from lightning disaster information and using computer technology, lightning disaster information is arranged and classified, thereby realizing automatic management of lightning disaster information.
Random behavior of concrete C45/55 XF2 used for prefabricated pre-stressed bridge beams is described on the basis of evaluating a vast set of measurements. A detailed statistical analysis is carried out on 133 test re...Random behavior of concrete C45/55 XF2 used for prefabricated pre-stressed bridge beams is described on the basis of evaluating a vast set of measurements. A detailed statistical analysis is carried out on 133 test results of cylinders 150 ~ 300 mm in size. The tests have been running in laboratories of the Klokner Institute. A single worker took all specimens throughout the period, and the subsequent measurements of the static modulus of elasticity and the compressive strength of the concrete were performed. The measurements were made at the age of 28 days after specimens casting, and only one testing machine with the same capping method was used. Suitable theoretical models of division are determined on the basis of tests in good congruence, with the use of Z2 and the Bernstein criterion. A set of concrete compressive strength （carried out on 133 test results of cylinders 150 ~ 300 mm after test of static modulus of elasticity） shows relatively high skewness in this specific case. This cause that limited beta distribution is better than generally recommended theoretical distribution for strength the normal or lognormal. The modulus of elasticity is not significantly affected due to skewness because the design value is based on mean value.展开更多
As a novel structural control strategy, tuned mass damper （TMD） inspired passive and semi-active smart building isolation systems are suggested to reduce structural response and thus mitigate structural damage due t...As a novel structural control strategy, tuned mass damper （TMD） inspired passive and semi-active smart building isolation systems are suggested to reduce structural response and thus mitigate structural damage due to earthquake excitations. The isolated structure＇s upper stories can be utilized as a large scaled TMD, and the isolation layer, as a core design point, between the separated upper and lower stories entails the insertion of rubber bearings and （i） viscous dampers （passive） or （ii） resettable devices （semi-active）. The seismic performance of the suggested isolation systems are investigated for 12-story reinforced concrete moment resisting flames modeled as ＂10 ~ 2＂ stories and ＂8 ＋ 4＂ stories. Passive viscous damper or semi-active resettable devices are parametrically evaluated through the optimal design principle of a large mass ratio TMD. Statistical performance metrics are presented for 30 earthquake records from the three suites of the SAC project. Based on nonlinear structural models, including P-delta effects and modified Takeda hysteresis, the inelastic time history analyses are conducted to compute the seismic performances across a wide range of seismic hazard intensities. Results show that semi-active smart building isolation systems can effectively manage seismic response for multi-degree-of freedom （MDOF） systems across a broader range of ground motions in comparison to uncontrolled case and passive solution.展开更多
文摘Starting from lightning disaster information and using computer technology, lightning disaster information is arranged and classified, thereby realizing automatic management of lightning disaster information.
文摘Random behavior of concrete C45/55 XF2 used for prefabricated pre-stressed bridge beams is described on the basis of evaluating a vast set of measurements. A detailed statistical analysis is carried out on 133 test results of cylinders 150 ~ 300 mm in size. The tests have been running in laboratories of the Klokner Institute. A single worker took all specimens throughout the period, and the subsequent measurements of the static modulus of elasticity and the compressive strength of the concrete were performed. The measurements were made at the age of 28 days after specimens casting, and only one testing machine with the same capping method was used. Suitable theoretical models of division are determined on the basis of tests in good congruence, with the use of Z2 and the Bernstein criterion. A set of concrete compressive strength （carried out on 133 test results of cylinders 150 ~ 300 mm after test of static modulus of elasticity） shows relatively high skewness in this specific case. This cause that limited beta distribution is better than generally recommended theoretical distribution for strength the normal or lognormal. The modulus of elasticity is not significantly affected due to skewness because the design value is based on mean value.
文摘As a novel structural control strategy, tuned mass damper （TMD） inspired passive and semi-active smart building isolation systems are suggested to reduce structural response and thus mitigate structural damage due to earthquake excitations. The isolated structure＇s upper stories can be utilized as a large scaled TMD, and the isolation layer, as a core design point, between the separated upper and lower stories entails the insertion of rubber bearings and （i） viscous dampers （passive） or （ii） resettable devices （semi-active）. The seismic performance of the suggested isolation systems are investigated for 12-story reinforced concrete moment resisting flames modeled as ＂10 ~ 2＂ stories and ＂8 ＋ 4＂ stories. Passive viscous damper or semi-active resettable devices are parametrically evaluated through the optimal design principle of a large mass ratio TMD. Statistical performance metrics are presented for 30 earthquake records from the three suites of the SAC project. Based on nonlinear structural models, including P-delta effects and modified Takeda hysteresis, the inelastic time history analyses are conducted to compute the seismic performances across a wide range of seismic hazard intensities. Results show that semi-active smart building isolation systems can effectively manage seismic response for multi-degree-of freedom （MDOF） systems across a broader range of ground motions in comparison to uncontrolled case and passive solution.
