腹板削弱型节点参数设计及梁单元刚度矩阵研究

PARAMETER ANALYSIS OF STEEL REDUCED WEB CONNECTIONS AND STUDY ON THE FRAME ELEMENT STIFFNESS MATRIX

实际工程中通过合理设计洞口尺寸可以迫使塑性铰在梁削弱截面处出现,避免节点先于构件发生破坏,保证结构的整体性使其免于倒塌,同时又可使室内管线从腹板空腔内通过,降低建筑层高,提高经济效益。在综合考虑了梁翼缘对腹板的约束要求、削弱截面处腹板的抗剪强度要求、梁端柱面处与削弱处截面的抗弯能力比以及防止受压板件局部失稳,可以确定矩形洞口尺寸大小和削弱截面距离柱表面的距离。梁腹板开洞后必然影响框架梁单元的刚度矩阵,从而影响结构的内力与位移。因此,有必要对腹板开矩形洞口框架梁单元的刚度矩阵进行研究。为了减少计算工作量,将梁单独作为一个杆单元,利用虚功原理推导其弹性刚度矩阵,并通过一算例与有限元结果进行了比较,两者结果吻合良好。

If the dimension of rectangular openings designed suitably in practical projects,pipes and wires will not only expediently pass through the beam web to reduce the story height of a building and increase economic benefits,but also move the plastic hinge far away from the connection.In this way,it can avoid the connection failure before the members,and ensures the structural integrity and make it no collapse.The dimension of openings and the distance between the opening and the column surface are determined by the restriction requirement for beam web by flange,the shear-bearing requirements of web,the ratio of the moment at beam end to the moment at reduced section and preventing compressive plate local buckling.While with openings on web,the element stiffness matrix of frame element and the internal force and displacements of structure will be affected out of question.Therefore,it is necessary to research the element stiffness matrix of frame element.In order to decrease the amount of calculation,the beam is handled as a link element.Virtual work theory is used to derive the element stiffness matrix of frame element with openings on web,and compared with the result of finite analysis method.It shows a satisfactory agreement between calculated and finite analysis results.