任一刚構之形式(包括共中各桿之長度,截面,及支承等情形)既經擬定之後,該剛構即有一套表示共彈性特質而與其荷載無關之刚構常數存在。採用此項剛構常數,不但其在任一荷載情形之下桿端力矩計算,大大簡化,而且在多種荷載情形下進行分析時,可將其与荷載無關及有關之二部份計算完全分开,因此省去他種分析法在每一種荷載情形下所必須重複之部份計算。實用之剛構,既常須在多種荷載情形下進行分析,故採用剛構常数分析法在實用中之優越性,至為顯明。採用剛構常数之分析法太約以立特(Wilhelm Ritter)教授之定點法為最早,而於表示剛構常數之各種方式中,亦以定點位置最為簡明,最為基本。本文首先指出:於任一剛構中,每桿之左右兩端各有一個而且祇有一个有獨立性之基本剛構常數,其計算係二個各向左右進行不相牽涉之步驟,但為計算剛構常數本身及桿端力矩之便利计,常須於每桿之左右二端,各另加計算一個無獨立性之輔助剛構常數,惟此外並不需要任何其他第三個剛構常数。恰於廿年以前,我國林同棪教授在國內外發表其力矩一次分配法(林氏原稱其法為“直接力矩分配法”,似欠妥),採用桿端之“約束剛度係數”(restraining rigidity factor),“修正傳遞係數”(modified carry-over factor),及“修正勁度”(modified stiffness)為 In the case of any form of rigid structure (including the length, cross section, and support of each rod in the common shaft), the rigid structure has a set of rigid constants that indicate the characteristics of the common elasticity and are independent of its load. The use of this rigid structure constant not only simplifies the calculation of the rod end moment under any load condition, but also greatly simplifies the analysis of the load-independent and related two-part calculations when analyzed under various load conditions. It eliminates the part of the calculation that he must repeat for each type of load. Practical rigid structures are often analyzed under a variety of load conditions. Therefore, the superiority of rigid structure constant analysis methods in practical use is clearly demonstrated. The method of rigid-constant analysis is the earliest method by which Professor Tai-Pro taught Wilhelm Ritter’s fixed point method. In various ways of representing rigid-constitutive constants, the fixed-point position is the most concise and most basic. In this paper, we first point out that in any one of the rigid structures, there is one and only one basic rigid-structure constant with the independence at each of the left and right ends of each rod. The convenience constants of the rigid-constitutive constants themselves and the rod-end moments are usually required to be at the two ends of each rod, each of which is calculated as an auxiliary rigid-frame constant without independence, but in addition, no other third constitutive constant is required. Just before the twilight years, Prof. Lin Tongxi of China published a method of primary distribution of moments at home and abroad (Lin used to call it the “direct torque distribution method,” which is regarded as defective), and adopts the “restraining rigidity factor” at the end of the rod. ), “modified carry-over factor”, and “modified stiffness” are