大跨度变截面连续组合梁受力分析和设计方法研究  

Mechanical analysis and design method of large-span variable cross-section continuous composite beams

作　　者：甄伟 聂鑫[2] 李伟 邱意坤 丁然[2] 樊健生[2] 张磊 张龑华 ZHEN Wei;NIE Xin;LI Wei;QIU Yikun;DING Ran;FAN Jiansheng;ZHANG Lei;ZHANG Yanhua(Beijing Institute of Architectural Design Co.,Ltd,Beijing 100045,China;Department of Civil Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]北京市建筑设计研究院股份有限公司,北京100045 [2]清华大学土木工程系,北京100084

出　　处：《建筑结构学报》2025年第3期38-49,共12页Journal of Building Structures

基　　金：国家自然科学基金杰出青年科学基金项目(52325802)。

摘　　要：采用大跨度变截面连续组合梁有助于增大使用净高、节省用钢量。为获取大跨度变截面连续组合梁的受力性能和合理形态特征,通过数值模拟开展在不同变截面段位置、坡度、跨中与端部梁高差异影响下典型变截面段模拟方式的适用性评估,建立静力工况竖向荷载下变截面连续组合梁理论分析模型,提出求取负弯矩区长度和各关键截面内力和变形的理论分析方法。针对钢梁和变截面形态相关的6类参数开展参数分析,发现随变截面段向跨中靠近,负弯矩区长度、梁端和跨中弯矩比例系数均先增大后变小,建议变截面段位置比例系数βs取值为0.25~0.30,初选高度比例系数βh取值为0.55~0.60,再对等安全度设计原则进行校核。推导了大跨度结构承载力设计在地震作用下的临界条件。对三跨变截面连续组合梁平面框架精细有限元模型开展罕遇地震下的弹塑性时程分析,发现近场地震作用下结构响应大于远场地震作用,钢梁最大内力约为静力工况的54%;罕遇地震下钢梁保持弹性,显示出该体系具有足够的安全储备。Large-span variable cross-section continuous composite beam was beneficial to increasing the net height and saving steel consumption.To obtain the mechanical properties and reasonable shape characteristics of large-span variable cross-section continuous composite beams,numerical simulations were conducted to evaluate the applicability of traditional modeling techniques of variable cross-section segment,for different variable cross-section segment position,slope,and the height difference between middle and end spans.A theoretical model for variable cross-section composite beams under static vertical loads was established,and an analytical method was proposed to obtain the length of the negative bending moment zone,the internal forces and deformations of each key section.Parameter analysis on six types of parameters related to steel beams and variable cross-sectional shapes was conducted.It is found that when the cross section approached the mid span,the length of the negative bending moment zone and the proportion coefficient of bending moments at the beam end and mid span increased first and then decreased.It is suggested thatβ,=0.25~0.30,β,=0.55~0.60,and the equivalent safety design principles should be checked.The critical condition in which seismic condition controlled the load bearing capacity of large-span structures was studied.The rare earthquake elastic-plastic time history analysis was conducted on a three span variable cross-section continuous composite beam planar frame structure using a refined finite element analysis model.It is found that the structural response under near field earthquakes is greater than that under far field earthquakes,and the maximum internal force of the steel beams is about 54%of that under the static service condition.The steel beam in the variable cross-section continuous composite beam still maintains elasticity under rare earthquakes,which indicates a sufficient safety reserve.

关 键 词：大跨度结构 组合梁 变截面 数值模拟 静力性能 抗震设计 

分 类 号：TU393.3[建筑科学—结构工程] TU245.1