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F.v.Emperger 1939年对先张法筋束的传统设计提出一个混合解法。著者在1941年提出有很多可能性的部分预应力。提出的解法是:(1)在常现荷载(也可以是恒载)时截面受压;(2)在作用荷载时避免可见裂缝(有限预应力,CEB 2级)。后一方法分别在1948年和1951/53年成功地引入英国和德国铁路部门。1951年在列日(Liege)做过很成功的疲劳试验。在这以前对只产生压应力的全预应力认为是唯一的解法;但是按Leonhardt所说,这却是一种能源浪费。林同棪用他的荷载平衡法(load counterbalaneing)在部分预应力方面取得很多的实际经验。
F. v. EMperger 1939 presents a hybrid solution to the traditional design of pre-tensioned tendons. Author in 1941 proposed a lot of possibilities of partial prestressing. The proposed solution is: (1) The section is under normal load (which can also be dead load); (2) The visible crack is avoided at the applied load (finite prestress, CEB level 2). The latter method succeeded in introducing the British and German railways in 1948 and 1951/53, respectively. In 1951 in Liege (Liege) has done a very successful fatigue test. Until then it was the only solution to the full prestress that produced only compressive stress; but according to Leonhardt it was a waste of energy. Using the load counterbalaneing method, Lin Tong-yang gained a lot of practical experience in partial prestressing.