The secondary moment in redundant structure of prestressed concrete

There is some limitations in consideration of the secondary moment in the design method of normal section bearing capacity of prestressed concrete according to the current Code. This paper clarifies that the shape,quantity,positive and negative sign of the second moment are different from common continuous beam and frame structure in prestressed concrete structure having special arrangement of prestressed bars and in cross beam system of multiple redundancy. The secondary moment is not always advantageous to supports while disadvantageous to middle point span. The secondary moment of cross beam may not be a linear distribution between two supports.