ABSTRACT
This chapter focuses on a method of placing continuous steel-reinforcing ties, known as ‘stability ties' to resist the effects of accidental loading or damage, and to prevent progressive collapse. It examines why ties are needed and explains the resulting structural mechanisms in the event of accidental loading. The best way of providing stability floor ties is to provide a continuous ring of reinforcement around each bay of floor slabs bounded by beams. In a three-dimensional precast concrete orthogonal slab field, the tie forces above will act in two mutually perpendicular directions, namely, along the beam as a ‘beam tie' and along the slabs as ‘floor ties'. Generous openings should be made in the floor slabs to ensure that any projecting tie steel in the beam may be lapped without damage to the slab or tie bar.
