STRUCTURE INSPECTION - Dearborn

shrubflattenΠολεοδομικά Έργα

25 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

72 εμφανίσεις

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Commercial Structures


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Structural Components


Footing




Piles



Foundation




Beams




Joists


Column


Substructure


Superstructure


Reinforced concrete


Re
-
bar


Pre
-
cast concrete
panel


Deflection


Cantilever

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Footings


A widening at the base of a
foundation or column.


Keep buildings from sinking


Larger footings needed for heavier
buildings or weaker soil.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Piles


A long column hammered into the ground
until it hits solid rock or cannot go any
deeper due to friction.


Used instead of footings


Used primarily where soils are poor


Expensive to install

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Foundations


Rest on footings


Usually made of concrete


Two functions:


Support the weight of the building


Act as a retaining wall to hold back the
surrounding soil when there is a basement or
underground parking garage.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Beams and Girders


Different terms for the same object.



Beams

are large horizontal members that
transfer floor loads, walls and roof loads to
the columns and foundation walls.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Joists


Transfer floor or roof loads to beams and
walls.



Usually steel in commercial buildings.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Columns

Columns

transfer loads vertically from beams
to footings or to other beams.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Superstructure & Substructure



Superstructure
: The portion of the
building structure starting above grade and
up.



Substructure
: The portion of the building
extending below the ground


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Reinforced Concrete and Re
-
bar


Reinforced concrete is a composite material
usually consisting of concrete and steel bars
(re
-
bar).

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Pre
-
cast Concrete Panels


Reinforced concrete building units
manufactured in a shop and delivered, ready
to use, to the building site.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Deflection


The amount of sag in a joist or beam when a
load is applied.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Cantilever


Like a diving board.


One end is rigidly secure, the other end is
free to move.


Example: A balcony (see next slide).


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Structural Assemblies and
Building Types


Single
-
family residential vs. commercial
structures


Tilt
-
up buildings


Cladding


Open
-
web steel joist


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Single Family Residential vs.
Commercial Structures


Commercial structures likely designed by
an engineer. Residential homes are not.


Commercial structures have more stringent
design criteria.


Commercial structures typically use
concrete and steel; residential homes
primarily use wood framing.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Tilt
-
up Building


A method of construction, not a building
type.


Used primarily for single story buildings.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Cladding Materials


Masonry



Stone

Granite



Marble

Pre
-
cast concrete

Metal panel

Glazing panel


Stucco


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Curtain Wall Cladding



A general term, not a specific material.


A cladding system that is entirely supported
by the structural frame but is not load
-
bearing.


The cladding is “hung” onto the building
like curtains.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Spandrel


The wall area between the top of a window
on one floor level and the sill of a window
on the floor level above.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Open
-
Web Steel Joist


Also referred to as OWSJ


One of the most common components used
for commercial building structures


Supports roof or floor loads and transfers
loads to beams and columns or supporting
walls.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

OWSJ & Corrugated Metal Pan

1.
The building frame is assembled.

2.
Open
-
web steel joists span between the
beams.

3.
A corrugated metal pan is welded to the
top of the joists.

4.
The metal pan is filled with concrete for a
floor structure.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Typical Problems and Concerns


Settlement


Foundation failure


Suspended slab failure


Buckling or damaged column


Hostile environment


Balcony damage


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Building Settlement

Tipping Settlement

Uniform Settlement

Differential Settlement

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Settlement


May affect the entire building.


Could have no implications or could be a
major problem.


You will be asked to make some judgment
calls.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Implications of Tipping
Settlement


The building may continue to settle.


The floors may not be level, affecting
building use.


Substantial costs may be associated with
stabilizing the building

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Implications of Uniform
Settlement


The building may continue to settle.


Services to the building may be affected.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Implications of Differential
Settlement


The building may continue to settle


The floors may not be level, affecting
building use.


Substantial costs may be associated with
stabilizing the building.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Foundation Failure


Main type occurs when foundation can no
longer hold back the surrounding soil.


In this case, horizontal cracks develop near
the mid
-
height.


If the foundation is not reinforced at this
point, the foundation will bulge and
eventually fail completely.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Suspended Slab Failure


A potential problem in parking garages
especially.


Pre
-
stressed and post
-
tensioned concrete
subject to failure due to exposure to road
salt.


Failure can be catastrophic.



Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Preventing Suspended Slab
Failure


Epoxy
-
coated steel (in conventionally
reinforced slabs, that is, re
-
bar)


Protective membranes


Concrete sealer


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Buckling or Damaged Column


Often caused by forklift collisions.


Minor damage can be repaired.


Major damage requires replacing the
column


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Hostile Environment

The process conducted in an industrial
building can affect the structure. Examples
include:


Arenas


Metal plating facilities


Dry cleaning facilities


Frozen food storage


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Balcony Damage


Reinforced concrete, again, is at issue.


When steel railings embedded in the
concrete balconies corrodes, it expands and
cracks the concrete. The concrete then falls
off.


In more severe cases, the balcony structure
is compromised.


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Inspection of the Structure


Performance
-
based review


Design analysis


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Performance
-
Based Review


A visual review of the visible components
of the building.


Works well for buildings that have some
history

time to settle, react to environment
& seasons, reveal deficiencies.


The trained observer can call for further
investigation of specific areas and problems
if warranted.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Design Analysis


Structural engineer analyzes the “as
-
built”
drawings of the building and verifies the
design.


Also reviews the actual construction.


Time
-
consuming and expensive


Useful if building is not very old and hasn’t
undergone changes, settling, seasons, etc.



Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Additional Testing


Verify assertions made during a
performance
-
based review.


Investigate an area prone to problems that
cannot be observed visually.


Determine the extent of a problem that has
been identified and defining the scope of the
repair.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Destructive vs. Non
-
destructive Testing

Non
-
destructive


X
-
ray a weld on a
structural steel component


X
-
ray concrete


Ultrasonic testing of
concrete


Destructive


Removing finish surfaces
to get a better look at a
structural component


Taking a core sample from
concrete to test its
compressive strength


Taking a soil sample to
verify the bearing capacity



Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Nondestructive Testing of Concrete Slab


Chain Drag Test


Schmidt Hammer Test


Half
-
cell testing


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Destructive Testing of Concrete
Slab


Compressive strength test


Chloride ion test


Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.

Soil Testing


Testing for structural characteristics of soil
is common when developing raw land.


May be warranted for an existing building
that has settled substantially.

Copyright Carson Dunlop & Associates, all rights reserved. This content may not be reproduced without the express written pe
rmi
ssion of the publisher, Dearborn Home Inspection.