UNIT 3 - STRUCTURAL SYSTEMS EXAM
QUESTIONS AND ANSWERS 100%
ACCURATE!
Questions about the structure a designer should be able to answer (even though we
don't design or modify structural elements) - ANSWER Is an element structural, and is it
feasible to modify it?
Can floor penetrations be made?
Is building movement expected, and how can it be accommodated?
Is a structural review necessary for the proposed new flooring load?
How should new interior construction elements interface with existing structural
elements?
Will fire protection of structural elements need to be repaired or should new protection
be included in the design?
Post and beam construction - ANSWER How most contemporary buildings are built.
Consists of steel, concrete, or timber columns (posts) supporting a grid of beams oh
which the flooring is applied.
Solid concrete walls - ANSWER Typically used as lateral shear walls to transfer lateral
loads, such as wind and seismic forces, to the foundation.
Two most common steel structural systems - ANSWER Beam and girder system
Open-web joist system
Beam-and-girder system - ANSWER Large members, called girders, spam between
columns, and smaller beans are framed into them.
The girders span shorter distances because they carry the weight of the beams.
Commonly found in mid- to high-rise office buildings.
, Easiest to penetrate with small openings for pipes and poke-through electrical outlets.
Suspended ceilings and other lightweight interior elements can also easily be hung from
the bottoms of the joists.
Two primary types of concrete structural systems - ANSWER Cast-in-place: concrete is
poured into forms, where it hardens before the forms are removed.
Precast concrete components are usually formed in a plant and shipped to the job site.
Types of cast-in-place systems - ANSWER Beam-and-girder: the slab is supported by
intermediate beans which are carried by larger girders.
Concrete joist system: comprised of concrete members spaces 24 or 36in apart,
running on one direction, which frame into larger beams. Because of the close-together
joists, it is hard to drill holes for pipes and conduit.
Flat plate construction: the floor slab is designed and reinforced to transfer loads directly
to the columns, which generally do not exceed 25ft spacing. It is commonly used in
situations where floor-floor height must be kept to a minimum.
Flat slab construction: similar to flat plate except drop panels (increased slab thickness
around the columns) are used to increase strength.
Waffle slab system (two way joist system): provides support for heavier loads at slightly
longer spans than the flat slab system. Often left exposed, with lighting integrated into
the coffers.
Precast concrete floors - ANSWER Single tees, double tees, and hollow-core slabs.
Single and double tee members are a popular form of precast construction because
they can simultaneously serve as beam and floor decking and are easy to erect.
Concrete block (CMUs) - ANSWER The common term for concrete unit masonry, also
known as concrete masonry units (CMUs).
Based on a nominal 4in module, with actual dimensions being 3/8" less than the
nominal dimension, to allow for mortar joints. Most common size is 8"x8"x16" unit.
Structural engineer must be consulted if an opening is required.
QUESTIONS AND ANSWERS 100%
ACCURATE!
Questions about the structure a designer should be able to answer (even though we
don't design or modify structural elements) - ANSWER Is an element structural, and is it
feasible to modify it?
Can floor penetrations be made?
Is building movement expected, and how can it be accommodated?
Is a structural review necessary for the proposed new flooring load?
How should new interior construction elements interface with existing structural
elements?
Will fire protection of structural elements need to be repaired or should new protection
be included in the design?
Post and beam construction - ANSWER How most contemporary buildings are built.
Consists of steel, concrete, or timber columns (posts) supporting a grid of beams oh
which the flooring is applied.
Solid concrete walls - ANSWER Typically used as lateral shear walls to transfer lateral
loads, such as wind and seismic forces, to the foundation.
Two most common steel structural systems - ANSWER Beam and girder system
Open-web joist system
Beam-and-girder system - ANSWER Large members, called girders, spam between
columns, and smaller beans are framed into them.
The girders span shorter distances because they carry the weight of the beams.
Commonly found in mid- to high-rise office buildings.
, Easiest to penetrate with small openings for pipes and poke-through electrical outlets.
Suspended ceilings and other lightweight interior elements can also easily be hung from
the bottoms of the joists.
Two primary types of concrete structural systems - ANSWER Cast-in-place: concrete is
poured into forms, where it hardens before the forms are removed.
Precast concrete components are usually formed in a plant and shipped to the job site.
Types of cast-in-place systems - ANSWER Beam-and-girder: the slab is supported by
intermediate beans which are carried by larger girders.
Concrete joist system: comprised of concrete members spaces 24 or 36in apart,
running on one direction, which frame into larger beams. Because of the close-together
joists, it is hard to drill holes for pipes and conduit.
Flat plate construction: the floor slab is designed and reinforced to transfer loads directly
to the columns, which generally do not exceed 25ft spacing. It is commonly used in
situations where floor-floor height must be kept to a minimum.
Flat slab construction: similar to flat plate except drop panels (increased slab thickness
around the columns) are used to increase strength.
Waffle slab system (two way joist system): provides support for heavier loads at slightly
longer spans than the flat slab system. Often left exposed, with lighting integrated into
the coffers.
Precast concrete floors - ANSWER Single tees, double tees, and hollow-core slabs.
Single and double tee members are a popular form of precast construction because
they can simultaneously serve as beam and floor decking and are easy to erect.
Concrete block (CMUs) - ANSWER The common term for concrete unit masonry, also
known as concrete masonry units (CMUs).
Based on a nominal 4in module, with actual dimensions being 3/8" less than the
nominal dimension, to allow for mortar joints. Most common size is 8"x8"x16" unit.
Structural engineer must be consulted if an opening is required.
