利用矩阵位移法计算桁架结构常需计算其支座反力。按桁杆轴力计算桁架结构支座反力需根据支座结点连于桁架结构的末结点或始结点判别正负号,不方便计算,而直接按矩阵位移法中单元杆端力的正负号约定推得的桁架支座反力计算公式则无此问题,既便于教学运用,又可有效简化程序编制。

A truss’ reactions often need to be solved after the structure is calculated by matrix displacement method. It is inconvenience that the rational solution based on the truss axial force needs to determine the sign of sum terms according to whether the beginning joint or the ending joint is connected to the support. But if the convention is changed to matrix displacement method, a new reaction formula based on element-end forces can be deduced and efficiently solve the deficiency, and then, can also decrease the complication in teaching and programming.