In this paper, a class of lattice supports in the lattice space Zm is found to be inherently improper because any rational parametrization from Cm to Cm defined on such a support is improper. The improper index for su...In this paper, a class of lattice supports in the lattice space Zm is found to be inherently improper because any rational parametrization from Cm to Cm defined on such a support is improper. The improper index for such a lattice support is defined to be the gcd of the normalized volumes of all the simplex sub-supports. The structure of an improper support S is analyzed and shrinking transformations are constructed to transform S to a proper one. For a generic rational parametrization RP defined on an improper support S, we prove that its improper index is the improper index of S and give a proper reparametrization algorithm for RP. Finally, properties for rational parametrizations defined on an improper support and with numerical coefficients are also considered.展开更多
在重庆九龙仓国际金融中心(IFS)施工中,超高大跨度桁架屋盖施工是一大难点。通过多次综合论证,采用在280 m高的楼层板面设置5 000 k N的钢结构格构柱支撑系统,分段吊装屋顶桁架、原位焊接的方法,以完成总重20 000 k N的屋顶桁架安装。...在重庆九龙仓国际金融中心(IFS)施工中,超高大跨度桁架屋盖施工是一大难点。通过多次综合论证,采用在280 m高的楼层板面设置5 000 k N的钢结构格构柱支撑系统,分段吊装屋顶桁架、原位焊接的方法,以完成总重20 000 k N的屋顶桁架安装。在格构柱支撑底端设置底部分配梁,将屋面桁架荷载有效传递给塔楼核心筒墙体和外钢柱,效益显著。展开更多
基金This research is supported by the National Key Basic Research Project of China under Grant No. 2011CB302400 and the National Natural Science Foundation of China under Grant No. 10901163.
文摘In this paper, a class of lattice supports in the lattice space Zm is found to be inherently improper because any rational parametrization from Cm to Cm defined on such a support is improper. The improper index for such a lattice support is defined to be the gcd of the normalized volumes of all the simplex sub-supports. The structure of an improper support S is analyzed and shrinking transformations are constructed to transform S to a proper one. For a generic rational parametrization RP defined on an improper support S, we prove that its improper index is the improper index of S and give a proper reparametrization algorithm for RP. Finally, properties for rational parametrizations defined on an improper support and with numerical coefficients are also considered.
文摘在重庆九龙仓国际金融中心(IFS)施工中,超高大跨度桁架屋盖施工是一大难点。通过多次综合论证,采用在280 m高的楼层板面设置5 000 k N的钢结构格构柱支撑系统,分段吊装屋顶桁架、原位焊接的方法,以完成总重20 000 k N的屋顶桁架安装。在格构柱支撑底端设置底部分配梁,将屋面桁架荷载有效传递给塔楼核心筒墙体和外钢柱,效益显著。
