Dead Loads and Idealization of Structural Members Steven Vukazich - - PowerPoint PPT Presentation

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Jul 10, 2023 574 likes •690 views

Dead Loads and Idealization of Structural Members Steven Vukazich San Jose State University What is a Dead Load? Dead Loads are Fixed Position Gravity Loads Examples are weights of the following: Ceiling, Flooring, Faade,

SLIDE 1

Dead Loads and Idealization of Structural Members

Steven Vukazich San Jose State University

SLIDE 2

Dead Loads are Fixed Position Gravity Loads Examples are weights of the following:

Ceiling,
Flooring,
Façade,
Structural Members.

Found from tables of weights of building materials (usually listed in weight/unit area)

What is a Dead Load?

SLIDE 3

Load Path

Metal Deck Beams (e.g. W14x22) Girders or Truss (e.g. W18x50) Columns Foundation

A B C D 1 2 3

22’-0” 22’-0” 1’-6” 1’-6” 1’-6” 18’-0” 18’-0” 18’-0” 1’-6” 6’-0” typ. W14x22 W14x22 W18x46 W14x22 W14x22 W18x46 W14x22 W14x22 W18x46 W18x46 W14x22 W14x22 DO DO DO DO DO DO DO DO W18x50 W18x50 W18x50 W18x50 W18x50 W18x50 W18x50 Dbl 6x6 1-1/2” 18 gauge metal deck typ.

Dead Load tables are usually constructed using the load path Section on next slide

Construct Dead Load Table for Roof Framing

SLIDE 4

1-1/2” 18 gauge metal deck 2” rigid fiberglass insulation 3 ply felt tar and gravel roofing

6’ - 0” 6’ - 0” 6’ - 0”

W14x22 spray-on fireproofing ceiling HVAC duct (mechanical)

Cross Section of Roof

SLIDE 5

Ceiling Support Hangers from Steel Framing at New Rec Center

SLIDE 6

Load Path →

Material To metal deck To beams (W14x22) To girders, truss (Lines 1-3) To columns 1-1/2” 18 gauge metal deck 2.82 (A) 2.82 2.82 2.82 Fireproofing 0.5 0.5 0.5 0.5 2” Rigid fiberglass insulation 3 (B) 3 3 3 3 ply felt tar and gravel roofing 5.5 (B) 5.5 5.5 5.5 Ceiling and Lighting 1 (B) 1 1 1 W14x22 @ 6 ft o.c. 3.7 (C) 3.7 3.7 Mechanical (plumbing, HVAC) 4 4 4 W18x50, truss 4 4 Weight of columns 1 Misc. 3 3 3 3 Total 15.82 23.52 27.52 28.52

Use 16 psf 24 psf 28 psf 29 psf

Notes:

A. From Vulcraft deck catalog.
B. From AISC steel manual “Weights of Building Materials”.
C. W14x22: (22 lb/ft)/(6 ft) = 3.7 psf.

Construct Dead Load Table

SLIDE 7

Weights of Building Materials from AISC Manual of Steel Construction

SLIDE 8

Loads carried to the beam from the metal deck are uniformly distributed over the beam

Deck Carries Uniform Load to Beams

SLIDE 9

Loads carried to the larger beam (girder) from the smaller beams are concentrated at the point of the connection and applied as point loads

Vertical (Gravity) Load Path

SLIDE 10

Framing at overhanging deck carries load to girder at edge Framing at Deck Overhang

SLIDE 11

A B C D 1 2 3

22’-0” 22’-0” 1’-6” 1’-6” 1’-6” 18’-0” 18’-0” 18’-0” 6’-0” typ. W14x22 W14x22 W18x46 W18x46 W14x22 W14x22 W18x46 W18x46 W14x22 W14x22 DO DO DO DO DO W18x50 W18x50 W18x50 W18x50 W18x50 W18x50 W14x22

Uniformly distributed dead load based on 24 psf Point dead load based on 28 psf