Principles of Agricultural Structures

Objectives• Identify and describe the characteristics of

the 4 major building types used in agriculture.

• Describe primary building structural components.

• Describe the types of loads acting on buildings.

• Interpret building plans.• Perform basic design calculations.

Major Building Types used in Agriculture

• Stud Frame Construction

• Pole (or post) Frame Construction

• Rigid Arch Construction

• Masonry Construction

Stud Frame Construction

16" or 24"

Foundation wall

Wall Stud

Plywood (or particle board)

Pole (Post) Construction

Concrete Pad

Ground level

Pole or Post

Wall Girts

Plywood or metal siding

Masonry Construction

Block ConstructionPoured-in-place Construction

Tilt-up Construction

Rigid Arch Construction

Primary Building Components

Foundation

Wall

Roof

Footing

Roof:

Weather protection.Lateral support of exterior walls.

Walls:Weather protection.Support vertical loads.Resist lateral loads.

Foundation and Footing:Transfer all structural loads to soil.

Soil:

Supports all building loads.

p. 65 of text.

AgriScience & Technology Center

Foundation and Slab

Common Roof Types

A.B. C.

D.F.E.

Shed Gable Gambrel

Hip Gothic Combination

Rafter Roof Components

Plate

Rafter

Ridge board

Truss Roof Components

Upper Chord Gusset

Lower Chord Web

Roof Terms

SpanRun

Rise

Roof Pitch

Expressed as:A. “Rise per foot of Run” or asB. “Fractional Pitch”

EXAMPLE

Rise = 3’Run = 12’

Stress, Strain and Building Loads

Stress vs. Strain

Types of Stress

Hooke’s Law

Structural Loads

Stress vs. Strain

Strain

Stress

Compressive Stress

Tensile Stress

Shearing Stress

Torsional Stress

What Types of Stress Can You ID?

Hooke’s Law

1-lb

2-lb

3-lb

4-lb

5-lb

Strain is proportional to stress within the elastic limits of a material.

Hooke's Law

0

14

86

42

0

5

10

15

0 1 2 3 4 5

Stress (lbs)

Strain (in. def.)

Elastic limits

Types of Building Loads

• Dead load – Weight of building materials.

• Live loads– Moveable load – Building contents that can move but are

generally stationary for extended periods.– Moving load – Building contents that move often.

• Snow load – Vertical load from weight of snow on roof.• Wind load – Pressure acting on roof and walls due to

horizontal wind.

A well-designed and constructed farm building will:• Withstand all “normal” loads without

structural failure.• Be as economical as possible (but no more

than possible!)• Efficiently serve its intended function• Have capacity for expansion• Be integrated into existing and intended

facilities plan

How can you ensure proper building design and construction? • Contractor

– Reputable– Licensed / Bonded

• Self– Use pre-engineered packages– Follow engineering plans from reputable source– Consult with professional engineer as necessary