© 2010 Delmar, Cengage Learning Instructor Resources for Lesson B Building Basics.

© 2010 Delmar, Cengage Learning

Instructor Resources for

Lesson B

Building Basics



Courtesy of Craig Allyn Rose



Basic Building Principles

• Buildings:– Designed to resist forces

• Gravity, wind, earthquakes, etc.

– Utilize a variety of materials and styles– Change, as do fire and building codes– Constructed according to current code – Often not in compliance with current codes



The Superstructure

• Superstructure – Distributes or carries the load

• Vertical extension above the foundation• Vertical load-carrying systems

– Frames, bearing walls, and combinations of both

• Horizontal load-carrying elements– Normally parts of floors and roofs

• Either wall bearing or frame bearing



Figure S-16 Superstructure.

Figure B-6 Bearing Wall.



Figure R-9 Roof.



Load Paths

• Transmit vertical load systems to ground– Allow buildings to remain upright

• Utilize a “top-down” approach• Loads impose forces within a structural

member• Loads and forces produce stresses



Figure L-8 Load Path. Figure B-3 Beams.



Load Paths (cont’d.)

• Stresses in materials and structural elements– Tension, compression, shear, and bending

• Load paths– May be altered by a variety of forces

• Improper or overstressed load paths– Created by both nature and firefighters

• Moving building parts– Indicate load path shifts and potential failure

• Always consider load paths at all structure fires



Figure S-10 Stress.



Connections

• Structural elements are joined at connections• Most common structural elements:

– Columns, beams, slabs, bearing walls, and trusses

• Other structural elements: domes, arches, shells, cables, and membranes

• Connections can fail when overloaded



Classification of Loads

• According to how loads are imposed– Live, dead, static, dynamic, impact, concentrated,

etc.

• According to where loads are imposed– Axial (through the center)– Eccentric (off center)– Torsional (twisting)



Specific Hazards Created by Buildings

• Building’s contents, structural elements, and nonstructural elements can burn

• Fire load– Includes contents, combustible structural elements,

and building materials

• Fire– Obeys laws of chemistry and physics– Will travel in vertical and horizontal concealed spaces



Specific Hazards Created by Buildings (cont’d.)

• Nonstructural elements: – Finishes, ceilings, HVAC systems, and interior

arrangements

• Voids conceal building components• Combustible concealed spaces

– Cause of many large-loss fires

• Penetrations in compartmentalized attics: – Allow heat, smoke, and fire to spread



Figure H-1 HVAC System.Figure V-1 Void.



Figure P-5 Penetration.

a

b



Features of Hazardous Buildings

• Unreinforced masonry walls• Parapet walls• Facades, overhangs, and marquees• Voids and concealed spaces• Unprotected steel and steel bar joists



Figure U-2 Unreinforced Masonry (URM).

Figure P-4 Parapet.



Figure F-1 Façade.



Features of Hazardous Buildings (cont’d.)

• Unprotected floor and roof support systems• Large buildings without sprinkler systems• Long-span floor and roof support systems• Window and door locations that:

– Restrict entry or egress– Allow for fire, heat, and smoke extension

• Combustible, non–fire stopped load-bearing elements



Hazardous Conditions in Buildings

• Poor condition due to lack of maintenance• Deficiencies in construction• Damage or deterioration to the superstructure• Distorted structural members (sagging, bowing,

leaning)• Out-of-plumb columns and walls



Hazardous Conditions in Buildings (cont’d.)

• Out-of-level floor support systems• Movement of stationary building components• Rapid changes in:

– Heat, smoke, or fire conditions during fire-ground operations



Summary

• Buildings, and fire and building codes change• Superstructure

– Distributes or carries load

• Load paths– Allows buildings to remain upright

• Improper or overstressed load paths– May be created by both nature and firefighters

• Load paths run through connections– Can fail when overloaded

© 2010 Delmar, Cengage Learning Instructor Resources for Lesson B Building Basics.

Documents

Transcript of © 2010 Delmar, Cengage Learning Instructor Resources for Lesson B Building Basics.