There are more than eight different design standards in use for the existing railway bridges in China, which have different applicabilities for bridges built in different periods. In this paper, the design load standa...There are more than eight different design standards in use for the existing railway bridges in China, which have different applicabilities for bridges built in different periods. In this paper, the design load standards in different periods are introduced and compared; The working status of the railway is investigated. According to the developing trend of separating passenger and freight transports, by comparing the computed results of the bridge effect and the fatigue cumulative damage, the applicabilities of bearing capacity and fatigue are analyzed for existing bridges. The results indicate that the bearing capacities of 99% existing bridges are suitable for the demand of 26.5 t (axle-weight) freight trains. However, for culverts, bridges with spans less than 20 m, longitudinal and transverse beams of through bridges, suspenders of truss bridges and other locally-stressed members should be evaluated and reinforced due to the increasing axle-weight.展开更多
Electricity industry restructuring should not sacrifice supply security to pursue economic efficiency. Till now there is no academic consensus on which electricity market design provides the least distorting investmen...Electricity industry restructuring should not sacrifice supply security to pursue economic efficiency. Till now there is no academic consensus on which electricity market design provides the least distorting investment incentives. Alternative approaches that have been adopted around the world for ensuring the appropriate level of investment in electric generation capacity are discussed, and much attention is devoted on the evaluation of capacity payment systems. The finding is that on one hand, capacity payment systems have good effect on reducing spot market price volatility and increasing the volume of generating capacity at the costs of relatively high total electricity prices; on the other hand, however, they are not robust against either the abuse of market power in the energy market or being manipulated.展开更多
文摘There are more than eight different design standards in use for the existing railway bridges in China, which have different applicabilities for bridges built in different periods. In this paper, the design load standards in different periods are introduced and compared; The working status of the railway is investigated. According to the developing trend of separating passenger and freight transports, by comparing the computed results of the bridge effect and the fatigue cumulative damage, the applicabilities of bearing capacity and fatigue are analyzed for existing bridges. The results indicate that the bearing capacities of 99% existing bridges are suitable for the demand of 26.5 t (axle-weight) freight trains. However, for culverts, bridges with spans less than 20 m, longitudinal and transverse beams of through bridges, suspenders of truss bridges and other locally-stressed members should be evaluated and reinforced due to the increasing axle-weight.
文摘Electricity industry restructuring should not sacrifice supply security to pursue economic efficiency. Till now there is no academic consensus on which electricity market design provides the least distorting investment incentives. Alternative approaches that have been adopted around the world for ensuring the appropriate level of investment in electric generation capacity are discussed, and much attention is devoted on the evaluation of capacity payment systems. The finding is that on one hand, capacity payment systems have good effect on reducing spot market price volatility and increasing the volume of generating capacity at the costs of relatively high total electricity prices; on the other hand, however, they are not robust against either the abuse of market power in the energy market or being manipulated.