Restriction of Yield-line analysis 1.For the yield-line theory to be valid,shear failures, bond failures.and primary compression failures in flexure must all be prevented; 2.The moment/curvature relationship must have a long horizontal portion when the yield capacity of the slab is reached: In practice,this restriction presents no difficulties because slabs are usually very much under-reinforcedRestriction of Yield-line analysis 1、For the yield-line theory to be valid, shear failures, bond failures. and primary compression failures in flexure must all be prevented; 2、The moment/curvature relationship must have a long horizontal portion when the yield capacity of the slab is reached; In practice, this restriction presents no dif iculties because slabs are usually very much under-reinforced