钢管混凝土双肢边柱双层肩梁设计方法研究

RESEARCH ON THE DESIGN METHOD OF DOUBLE-LAYER SHOULDER BEAMS WITH DOUBLE-LIMB SIDE COLUMNS OF CONCRETE-FILLED STEEL TUBES

为研究双肢边柱双层肩梁的设计方法,建立了4个双肢边柱双层肩梁的有限元模型,采用数值模拟的方法对上肩梁高度、中柱内肢中心距、下肩梁高跨比、中柱内肢高度、中柱内肢断面高度等参数对边柱双层肩梁承载力、破坏模式和内力分配规律的影响进行研究。结果表明:当内肢侧腹板先全断面屈服时,构件弹性承载力对应内肢侧腹板的全断面屈服时的承载力;当外肢侧腹板先全断面屈服时,构件的弹性承载力可偏保守取下肩梁内、外两侧剪力相等时对应的弹性承载力;下肩梁内肢侧剪力计算同单层肩梁;同时给出了不同情况时下肩梁主要断面的剪力计算式,并以此推出下肩梁内、外两侧剪力相等的临界值,用于判定下肩梁内、外两侧的屈服顺序;并结合断面应力分布特点提出了双层肩梁的设计方法。

In order to study the design method of double shoulder beams with double-limb side columns,four finite element models of double shoulder beams with double-limb side columns were constructed.The finite element numerical simulation method was adopted.The height of upper shoulder beams,center distance of inner limbs of middle columns,height-span ratio of lower shoulder beams,height of inner limbs of middle columns and section height of inner limbs of middle columns were taken as parameters to determine the bearing capacity,failure mode and internal force distribution in double-layer shoulder beams of side column.The influence of the laws were studied.The results showed that:when the side webs of inner limbs yielded first,the elastic bearing capacity of the members was equaled the bearing capacity of the full section yield of the side webs of the inner limb;when the full section of side webs of outer limbs yielded first,the elastic bearing capacity of the members could be conservatively taken as the corresponding elastic bearing capacity when the internal and external shear forces of the shoulder beam were equal.The shear force calculation of the inner limb of the lower shoulder beam was the same as that of the single-layer shoulder beam;and the shear calculation formula of the main section of the lower shoulder beam in different conditions was given,and the critical value of the shear force on both sides of the lower shoulder beam was deduced,which was used to determine the yield order of the inner and outer sides of the lower shoulder beam.Combined with the characteristics of cross-section stress distribution,the design method of double-layer shoulder beams was proposed.