The multiple active lever-type tuned mass dampers (MALTTMD), consisting of many active lever-type tuned mass dampers (ALTTMDs), is proposed in this paper to gain a control system with high robustness and effectiveness, in which the static and dynamic stretching of the spring may be freely adjusted. The main objective of the present study is to evaluate the control performance of the MALTTMD (including the MALTTMD stroke). The evaluation of the MALTTMD is performed in terms of both minimizing the maximum dynamic magnification factors of the structure and the maximum dynamic magnification factor of every ALTTMD in the MALTTMD. The results indicate that the MALTTMD with the actuator set at the mass block can render better effectiveness and higher robustness compared to the MALTTMD with the actuator set at other locations and also has higher effectiveness than a single ALTTMD with equal total mass ratio and normalized acceleration feedback gain factor (NAFGF). More importantly, the static and dynamic stretching of the spring in the MALTTMD with the actuator set at the mass block may be freely adjusted in accordance with the practical requirements through changing the mass block location, while approximately maintaining the same control performance as the AMTMD. Additionally, a parametric study is carried out to examine the effect of the dominant ground frequency ratio (DGFR) on designing the MALTTMD.

对大跨度桥梁、大跨空间结构、高层建筑、高耸塔桅结构等建筑物和构筑物而言，风荷载是结构抗风设计、防灾减灾分析的控制荷载之一。风与上述结构间的相互作用十分复杂，可通过风洞试验、现场实测、数值模拟等方法获取详细可靠的风荷载数据。本文简要介绍了大气边界层风特性与风荷载作用特点，回顾了结构风工程中风洞试验与现场实测的基本情况，讨论了风荷载时程的各种数值模拟技术，展望了风荷载测试与模拟技术研究的趋向。

大跨度网壳结构日趋多样化、大型化、复杂化。风荷载常常起主要甚至决定性作用，风振动力响应特性研究日益受到关注与重视。目前，网壳结构的抗风设计参数取值方法尚不完善，大多沿用高层或高耸结构设计规范。本文讨论了网壳结构风振响应的时程分析计算方法，并利用节点位移风振系数、单元内力风振系数等概念来衡量网壳结构风振特性。对一类K6-6型单层球面网壳结构进行了包括几何参数、结构参数、阻止比参数、边界约束参数、平均风速参数等多种工况的风振特性参数影响分析，得出陔类单层球面网壳结构在上述各种参数工况下风振系数的变化规律，为单层网壳结构抗风设计、防灾分析提供一定参考。

Based on relating equation group, a simp lifiedmethod was presented in term s of thematrix disp acement method, which can be conveniently used to study the re-dist ribution of the internal forces and disp lacement of truss structures due to the removal of members. Such removal is treated as though adding a load case to the o riginal truss, and the re-dist ribution can be calculated withoutmodifying the original global stiffnessmatrix. The compu-tational efficiency of thep resented method is faster by square times than that of the matrixdisp lacement method. The results from the two methods are identical.

本文把带肋扁壳的肋看作为一层网壳，且连续化为下层壳，并与带肋壳的壳板即上层壳组成协同工作的拟双层壳计算模型，进而可按弹性小挠度薄壳理论分析计算带肋扁壳。文中推导建立了一般情况下带肋扁壳混合法的基本方程式。这种构造上的拟双层壳一般不存在中面，因而壳体的薄膜内力、弯矩与薄膜应变、弯曲应变是耦合的，序在一个耦合矩阵，它可充分反映肋与壳板偏心矩e的影响。对于两向正交正放与三向带肋扁亮文中作了详细的讨论。并说明了在一定条件下，基本方程式可简化为一个构造上正交异性甚至各向同性单层扁壳的基本方程式，以方便计算和工程应用。文中附有算例两则。