3.1 Introduction N d.tdk=do、·πd2/4 Ha (6) N T= d dos A dx ,+dc. True bond stress (c) o,+do, In-and-out stress (d) Bond stress will not exist unless the steel (e) Os +do 圭 stresses change between any two sections 土本工程学院 3 3 3 3.1 Introduction dx d d s  4 = / 4 2 d dx d d    =  s  True bond stress In-and-out stress Bond stress will not exist unless the steel stresses change between any two sections