A 5-level cast-in-place parking structure case study on a 60 ft x 60 ft column grid — worked post-tensioned flat plate sizing, ramp geometry, chloride-exposure durability detailing, and expansion joint design from real thermal movement.
The project brief: a 180 ft x 240 ft, 5-level parking garage needs a long-span, column-free structural system laid out on a 60 ft x 60 ft grid chosen to exactly fit a standard double-loaded parking module — two 18 ft stall rows plus a 24 ft drive aisle. Every downstream decision, from slab thickness to ramp length to expansion joint spacing, traces back to that one grid choice.
This module walks the whole design the way a real parking structure engineer would: a two-way post-tensioned flat plate sized by span-to-depth ratio with tendon spacing solved from a target precompression, a speed ramp's geometry worked from floor-to-floor height and grade, the chloride-exposure-driven concrete mix and tendon encapsulation unique to parking structures, and an expansion joint spacing calculated from real seasonal thermal movement. The full worked numbers, complete bill of materials, and finished design reasoning are part of the unlocked module below.