Yield line theory based loading capacity analytical model of bolted endplate connections to square hollow section columns

为研究螺栓端板连接方钢管柱的承载力,进行了11个连接件的单调静力试验,分析了钢管和螺栓的3种典型破坏模式,以及钢管管壁厚度、螺栓列距与直径、盲孔螺栓Hollo-bolt构造等因素对连接件承载力的影响,提出了预测该类连接承载力的改进屈服线计算模型。研究结果表明：螺栓端板连接方钢管柱的破坏模式与钢管管壁厚度以及螺栓列距相关,承载力随钢管厚度以及螺栓列距和直径的增大而增大;通过连接件整体位移和钢管管壁连接面竖向位移与荷载关系,按双线性屈服模型得出的承载力预测值与试验值相近;由连接件试验结果折算得到的预测结果可用于此类节点的屈服弯矩计算。基于屈服线理论建立的连接件承载力的计算模型的计算结果,与试验结果比较,二者吻合较好。     

Longitudinal, lateral and torsional oscillations of a square section tower model in an atmospheric boundary layer

The longitudinal, lateral and torsional response of a square building under an atmospheric boundary layer is determined using a linear model with three degrees of freedom for different angles of incidence of wind. The experimental results are compared with existing analytical models, and an expression for predicting the lateral response for different angles of incidence and for a wide range of reduced velocities is presented.     

An improved assessment model of variable frequency-driven direct expansion air-conditioning system in commercial buildings for Taiwan green building rating system

Because of the superior performance of the multi-unit variable frequency-driven (VFD) direct expansion (DX) air-conditioning system, installing this kind of system in rental commercial buildings, dwelling houses, and schools is becoming more and more popular in Taiwan. Even though the features and characteristics of the multi-unit VFD DX system are different from those of the central system, it is still assessed by the conventional method used for evaluating the efficiency of all air-conditioning systems, which is designed mainly for central systems. This article explains the problems that occur when the current assessment method is applied to the multi-unit VFD DX system. An alternative assessment method is proposed.