Composite decking and deeper rolled sections can remove an entire structural storey.
Where the weight goes
A transfer girder solves a planning problem with tonnage. Deeper universal beams with composite action often solve the same problem with a fraction of the steel.
Vibration, not strength, is the limit
At 15m clear spans, serviceability governs. Damping strategy and slab mass matter more than a further grade jump.
Procurement effects
Fewer bespoke plate girders means shorter fabrication queues and a more predictable erection sequence.