Flat Spanning Systems - Architectural Structures - Lecture Slides, Slides of Structural Design and Architecture

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Concrete Spans 1 Lecture 25

ARCHITECTURAL STRUCTURES:

FORM, BEHAVIOR, AND DESIGN

lecture

twenty five

concrete construction:

flat spanning systems

http:// nisee.berkeley.edu/godden

Concrete Spans 2 Lecture 25

Reinforced Concrete Design

• economical & common
• resist lateral loads

Concrete Spans 4 Lecture 25

Reinforced Concrete Design

• beam supported
  • slab depth ~ L/
  • 8”–60” deep
• one-way joists
  • 3”–5” slab
  • 8”–20” stems
  • 5”-7” webs

The Architect’s Studio Companion

Concrete Spans 5 Lecture 25

Reinforced Concrete Design

• two-way joist
  • “waffle slab”
  • 3”-5” slab
  • 8”-24” stems
  • 6”-8” webs
• beam supported slab
  • 5”-10” slabs
  • taller story heights

Concrete Spans 7 Lecture 25

Reinforced Concrete Design

• one-way slabs (wide beam design)
  • approximate analysis for moment & shear coefficients
  • two or more spans
  • ~ same lengths
  • wu from combos
  • uniform loads with L/D  3
  •  (^) n is clear span (+M) or average of adjacent clear spans (-M)

Concrete Spans 8 Lecture 25 Architectural Structures

Reinforced Concrete Design

Concrete Spans 10 Lecture 25 Architectural Structures

Reinforced Concrete Design

Concrete Spans 11 Lecture 25

Shear in Concrete

• at columns
• want to avoid

stirrups

• can use shear

studs or heads

Concrete Spans 13 Lecture 25

Shear in Concrete

• at columns with waffle slabs

http:// nisee.berkeley.edu/godden

Concrete Spans 14 Lecture 25

Openings in Slabs

• careful placement of holes
• shear strength

reduced

• bending &

deflection can

increase

Concrete Spans 16 Lecture 25

General Beam Design (cont’d)

• custom design:
  • longitudinal steel
  • shear reinforcement
  • detailing

Concrete Spans 17 Lecture 25

Space “Frame” Behavior

• handle uniformly distributed loads well
• bending moment
  • tension & compression “couple” with depth
  • member sizes can vary, but difficult

Concrete Spans 19 Lecture 25

Folded Plates

• increased bending stiffness with folding
• lateral buckling avoided

Concrete Spans 20 Lecture 25

Folded Plates

• common for roofs
• edges need

stiffening

http:// nisee.berkeley.edu/godden