Structural System - Intermediate Steel Moment Frame (IMF)
Frame type - Perimeter/distributed IMF; Z-shaped (offset) plan school with three wings at three different roof heights
Number of stories - 3 (classroom wing); 2 (link wing); 1 tall story (gymnasium)
Story heights - Classroom: 3 @ 12 ft (roof 36 ft). Link: L1 12 ft, L2 12 ft (roof 24 ft). Gym: single 26-ft story (roof 26 ft).
Analysis procedure - ELF; SDC C; Risk Category III (school, >250 occupants) - Ie = 1.25
Design standards - AISC 360, AISC 341 (Section E2), AISC 358, ASCE 7

## Material Properties
- W-shapes: **ASTM A992**, **Fy = 50 ksi**
- Plates: **ASTM A572 Grade 50**
- Classroom/link floors: composite - 3 in. NW concrete on 2 in. deck
- Gym roof: long-span joists/trusses (agent to select) with 1.5B metal deck; classroom/link roofs: composite deck roofs

## Gravity Loads
| Load Type | Magnitude |
|------------|-----------|
| Dead Load | 75 psf classroom/link floors; 30 psf classroom/link roofs; 24 psf gym roof (trusses/deck/MEP/ceiling) |
| Cladding Load | 25 psf (brick veneer on studs, all wings) |
| Floor Live Load | 40 psf classrooms + 15 psf partitions; 80 psf corridors (first-floor corridors 100 psf); link L2 library 60 psf + stack allowance 90 psf over Grids 4-5/B-D |
| Roof Live Load | 20 psf (Lr) all roofs |
| Snow | pg = 30 psf, Is = 1.1 (RC III); drift checks at BOTH roof steps (36'->24' and 26'->24') |

## Seismic Design Data
- SDS = 0.48 g, SD1 = 0.20 g, Site Class D, Risk Category III, Ie = 1.25, SDC C
- IMF: R = 4.5, Cd = 4, Omega_0 = 3; permitted without height limit in SDC C
- Horizontal irregularity: Type 2 re-entrant corners at both Z offsets

## Wind Design Data
- V = 115 mph (RC III map), Exposure C. Wind likely governs the gym (light roof, tall open story).

## Building Plan Geometry (Z-SHAPED PLAN, THREE ROOF HEIGHTS)
  - Column Grid:
      - X-Axis: Grids 1 to 8 (7 bays @ 28'-0" = 196'-0")
      - Y-Axis: Grids A to E (4 bays @ 28'-0" = 112'-0")
  - Z-shape (offsets step southward going east):
      - CLASSROOM WING (3 stories, roof 36'): Grids 1-4 / A-C (84' x 56')
      - LINK WING (2 stories, roof 24'): Grids 4-6 / B-D (56' x 56')
      - GYMNASIUM (1 tall story, roof 26'): Grids 6-8 / C-E (56' x 56'); long-span roof framing spans 56' in Y between Grids C and E; interior Grid D columns OMITTED within the gym
      - All other grid zones are open (site/landscape)
  - Wing interfaces: classroom and link share Grid 4 (B-C segment); link and gym share Grid 6 (C-D segment). Floor at 12' aligns between classroom and link; gym has no intermediate floor.

## IMF Frame Locations (fully restrained moment connections per AISC 358 prequalification or IMF-qualified WUF-W)
Classroom wing:
  - X-direction: Grid A bays 1-2, 2-3, 3-4 (L1-L3); Grid C bays 1-2, 2-3 (L1-L3)
  - Y-direction: Grid 1 bays A-B, B-C (L1-L3); Grid 4 bay A-B (L1-L3)
Link wing:
  - X-direction: Grid B bays 4-5, 5-6 (L1-L2); Grid D bays 4-5, 5-6 (L1-L2)
  - Y-direction: Grid 5 bays B-C, C-D (L1-L2)
Gymnasium:
  - X-direction: Grid C bays 6-7, 7-8 (full-height single story); Grid E bays 6-7, 7-8
  - Y-direction: Grid 6 bay C-D; Grid 8 bays C-D, D-E

## IMF Requirements (AISC 341 E2)
- Moment connections: prequalified per AISC 358 (RBS or WUF-W) qualified for IMF (0.02 rad interstory drift capacity)
- Beam and column sections moderately ductile per Table D1.1
- Panel zone per AISC 360; continuity plates as required
- Gym moment columns: check tall-story stability (26 ft unbraced about both axes at the open story; no intermediate floor bracing)

## Member Sizing Rules
- One beam size per frame line per story; one column size per wing per 2 stories
- Gravity framing: one size per story per wing (agent to determine); gym long-span roof members one size
- Base fixity: gym moment columns FIXED (tall single story drift control); all other columns pinned. Gravity connections pinned.
