中心支撑-钢框架高层公寓的结构分析及优化研究
马逸敏,马宏伟,翁益显,杨致远

(华南理工大学 土木与交通学院,广东 广州 510641)

中心支撑钢框架; 剪力分配; 变形协调; 结构优化; 理论计算

Structural analysis and optimization of high-rise apartments with concentrically braced steel frame
MA Yimin, MA Hongwei, WENG Yixian, YANG Zhiyuan

(School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510641, China)

concentrically braced steel frame; shear force distribution; deformation compatibility; structural optimization; theoretical calculation

DOI: 10.15986/j.1006-7930.2022.04.016

备注

中心支撑-钢框架(CBF)结构作为双重抗侧力体系常用于高层建筑,水平荷载计算时涉及剪力在两种抗侧力体系间的分配,目前,简化的理论计算方法有按支撑体系与框架体系间的抗侧刚度比值或者按照两种体系的变形协调来分配总剪力.对于高层建筑,尤其是对于长条形、立面有收缩的公寓建筑,理论计算方法存在偏差,需要对两种理论计算方法的适用性进行评价.同时,长条形建筑的长宽比大,沿建筑长边的框架榀数较多,与常规CBF结构相比,框架体系分担的剪力较大,从受力角度出发,可通过将梁柱节点设为铰接,释放柱端弯矩,减小框架体系受到的剪力,从而改变剪力在支撑体系与框架体系之间的分配比例,实现减小框架柱截面尺寸和减少用钢量.该优化方法通过改变受力体系的内力实现减重,值得重视.对某12层长条形高层公寓分析结果表明:对于长条形、立面有收缩的公寓建筑,基于变形协调的理论计算方法得到的剪力在两种抗侧力体系间的分配与电算接近,误差最大为负13.9%; 而基于刚度比的方法与电算相差较大.对框架体系的部分梁柱节点设置为铰接后,支撑与框架体系受到的剪力占底部总剪力的比例分别增大4%和减小4%,当减小框架体系柱截面,并保持结构的周期比、最大层间位移角、最大应力比不变,结构的单位用钢量可以减少4.7%.
Concentrically braced steel frame(CBF)structure is often used in high-rise buildings as a dual lateral force resistance system. The horizontal load calculation involves the distribution of shear force between the two lateral force resistance systems, and at present, the simplified theoretical calculation methods of the distribution of total shear force are based on the ratio of the lateral rigidity of the bracing system and frame system, or the deformation compatibility of the two systems. For high-rise buildings, especially for long-striped apartment buildings with shrinking body shape, there are deviations in the theoretical calculation methods, and the applicability of the two theoretical calculation methods needs to be evaluated. Meanwhile, the length-to-width ratio of the long-striped building is large, and there are many frames along the long side of the building. Compared with the conventional CBF structure, the frame system shares a larger shear force. From the point of view of force distribution, the beam-column joint can be set as hinged, so that the bending moment at the column ends can be released, and the shear force shared by the frame system can be reduced. Therefore, the distribution ratio of the shear force between the bracing system and frame system can be changed to reduce the frame column cross section size and steel consumption. This optimization method achieves weight reduction by changing the internal force of the force-bearing system, which is worthy of attention. The analysis results of a 12-story long-striped high-rise apartment show that: for a long-striped apartment building with shrinking body shape, the distribution of shear force between the two lateral force resistance systems achieved by the theoretical calculation method based on the deformation compatibility is close to that achieved by the software, and the maximum error is minus 13.9%, while the results achieved by the theoretical calculation method based on rigidity ratio is quite different from that achieved by the software. After some of the beam-column joints of the frame system are set to be hinged, the ratio of the shear force shared by the bracing system and the frame system to the total base shear force increases by 4% and decreases by 4%, respectively. When the column cross section of the frame system is reduced and the period ratio, the maximum story drift ratio and the maximum stress ratio of the structure are kept unchanged, the unit steel consumption of the structure can be reduced by 4.7%.