Bursting and Spalling in Pretensioned U-Beams - Ferguson ...

The trial specimens included one 40 in. deep rectangular beam and two 22 in.deep inverted T-beams, prestressed with 0.08 in. or 0.20 in. wires. Seven-wire strand,though developed almost ten years before (Scott, 2004), was still making its way intostandard practice at this time.As shown in Figure 2.15, the rectangular beam showed strains of 150 microstrainor greater in both the bursting and spalling zones. This level of strain is approximatelythat which would be expected to cause cracking.Figure 2.15 Bursting & spalling strains in Base rectangular beamFor the inverted T-beams (IT-beams), transverse tensile strains were measuredbetween the gage lines on the web (Figure 2.16), i.e. in the spalling zone. The twoIT-beams differed significantly both in the provided end-region transverse reinforcement26