PRECAST
CONCRETE STRUCTURES
Precast
Concrete Fabrication
Prestressed
products
In
molds
Stressed
cables to tension before concrete pour
Release
cable tension after hardening placing concrete into compression
Further
strengthening by nonstressed reinforcing bars, rods, and wire
Reinforced
products
Also
poured in forms with reinforcing bars, rods, and wire but without prestressed
strands
Horizontal
structures
Slabs, Beams or Lintels
Vertical
structures
Piles, column, or piers
Precast
Concrete Framing Plans
Precast
Concrete Faming Plans
Blockouts
Opening
in a precast member for windows, doors, skylights, conduit, ductwork, piping,
etc.
Wooden,
styrofoam, or cardboard placed in form to deflect and displace concrete
Removed
after concrete hardens
Labeled
for ID in legend
Mark
numbers
Assign mark numbers to each individual
member
Same number only for members that have the same
length, width, thickness, shape, reinforcing, and stranding
Product
Schedules
Summary
of all structural products in Framing Plans
Containing,
as a table or chart
Mark
Numbers
Quantity
required
Description
of product type
Length
Width
Dimension
of flange weld plates for
Dimension
of lift hooks
Remarks for size of Blockouts and
miscellaneous notes
General
notes on the first/cover page, specific notes on individual pages
Legend
Key
to explain symbols and abbreviations
General
symbols/abb. on the first/cover page, specific symbols/abb. on individual pages
Drawing
Framing Plans
Order
Column
Framing Plan
Using
the raw data, determine appropriate scale
Layout
column centerlines
Dimension
Label
column grid letter and number designations
Construct
column by depth and width at centerline intersection
Assign
mark numbers
Add
schedules
Page
formatting for border and title blocks
Beam
Framing Plan
Based
on column centerline dimensions, determine beam lengths
One
inch joint gap between abutting beams
Dimension
for length and location
Assign
mark numbers
Complete
schedules
Assign
designations for connection details
Label
‘North’
Floor
Framing Plan, if applicable
Bearing
surface edges of beams drawn as hidden lines
Calculate
required framing from raw data, draw and dimension
Establish
blockouts, dimension and label
Establish sections using cutting plane lines and
designations to clarify internal relationships
Establish mark numbers
Complete schedules, notes, legends, ‘North’,
borders, and titleblocks
Wall
Framing Plan
Using
the raw data, determine size and type of product
Determine
total amount, widths, and heights of framing materials
Layout
wall panel framing
Drawings
consist of plan and elevation views as seen from the inside of the building
Columns
and beams are superimposed with phantom lines
Locate
and size openings for blockout designation
Complete schedules, notes, legends, ‘North’,
borders, and titleblocks
Repeat Floor and Wall Framing Plans, as
appropriate to the number of floors in the structure
Roof
Framing Plan
Same
approach as Floor Framing
Precast
Concrete Sections
Precast
Concrete Sections Defined
Prepared
as single line symbolic representations or scaled duplicates of actual shapes
Precast
Concrete sections show only structural or load-bearing components
Architectural
sections show interior/exterior features
Full
Sections
Cut
through the entire structure
Longitudinal
Sections across length of structure
Cross
Sections across width of structure
Partial
Sections
Clarify
internal relationships
Offset
Sections
Use
of cutting lane lines that do not run straight
Section
Conventions
All
materials have standard symbols for use in sections
Drawing
Precast Concrete Sections
Obtain
information from framing plans and raw data
Determine
sectional drawings are needed
Should
the sectional drawings be full, partial,
or offset
What
materials are used?
How
do the components fit together?
Important
heights and distances are noted
Base
elevations
Top
of foundations
Floor
elevation(s)
Roof
elevation
Top
of elevations
Scaled
representations ¾” = 1’-0” or larger
Precast
Concrete Connection Details
Precast
Concrete Connection Details Defined
Precast
concrete members are fabricated offsite and shipped by truck or train for
erection
Connections
achieved by bolting, welding, or a combination
Connection
details are plan views with sections cut to show elevations
Column
Baseplate Connections
Cast
heavy steel baseplate in one end with holes to fit over anchor bolts
Plate
extends beyond the column with external/exposed anchor bolt connections
Plate
flush with column sides with pockets to accommodate anchor bolt connections
Drawing Baseplate Connection Details
Select
appropriate scale
Construct elevation view showing anchor bolts,
footing, leveling nuts, washers and locking nuts
Section horizontally to look down on column and
baseplate
Label components
Bolted
Beam to Column Connection Details
Connection
details drawn for each letter designation called on framing plan
The
same, similar , or opposite connections noted similar (Sim) opposite hand (Opp
Hd)
¾”
Neoprene bearing pad between beams to avoid damage
Six
basic beam to beam connections
Single
beam bearing fully on column with ½-1” joint between abutting beams
Two rectangular beams bearing on the same column
with ½-1” joint between abutting beams
Single L-shaped beam bearing on a column
Two L-shaped beams bearing on the same column
with ½-1” joint between abutting beams
Single inverted-Tee bearing fully on a column
Two inverted-Tees bearing fully on a column with
½-1” joint between abutting beams
Drawing Beam to Column Connection details
Plan and sectioned elevation views showing
column, beam(s), blockouts, threaded rod(s), washers/nuts, bearing pads and
anything else
Welded
Connections
The
most frequently used connection method is welding due to its versatility
Flange connections in double-tee and
single-tee
Base
and top connections for wall panels
Connections
between beams and floor or roof members
Stem
connections for double and single tees
Flange
weld plate welded to a reinforcing bar anchor provides smooth surface for field welds
Weld
Plate-Angle connection versatile adoption to misalignment by shifting the angle
Weld
Plate-Strap uses matched weld plates connected by a single strap welded to both
Stem
Plate-Weld Strip to permanently fasten single and double tee stems to continuous strip
Drawing Welded Connections
Precast
Concrete Haunch Connections
Bearing
surface cast onto column or wall in a secondary pour to support beam or roof member
Flat
support face with tapered back-side
Double
haunch occurs on both sides of column
Column haunch connections usually bolted to
embedded threaded rod, wall connections are usually welded
Draw plan and sectioned elevations showing
column, beam(s), haunch(s), blockouts, threaded rod(s), washers/nuts, bearing
pads and other information
Precast
Concrete Fabrication Details
Shop
Drawings Defined
Detailed Fabrication Drawings and Bill of
Materials used in fabrication of concrete products and connectors they contain
Fabrication
Details Defined
Separate Orthographic Drawings of each beam,
column, wall panel, roof/floor member, and metal connectors
Constructing
Fabrication Details
Column
fabrication details
Two
adjacent orthographic views with overall dimensions
Section(s) showing reinforcing bars or strand
patterns , represented by dashed lines, with size, spacing, location dimensions
and numeric designations
Baseplate
configuration diagram with width, length, and thickness dimensions
Special
view(s) showing size, location, and embedment of threaded rods with dimensions
Beam
Fabrication Details
Same
content as Column Fabrication detail
Additionally
requirements
Blockout
sizes, locations, and designations
Metal
connectors with size and location
Floor/Roof
Member Fabrication Details
Includes
Single and Double
Similar
content as Column and Beam Fabrication Details
Prestressed
strand run the entire length of the member and are not dimensioned
Wall Panel Fabrication Details
Similar
to Floor/Roof Fabrication Details
Exaggerated length to width ratio, and repetitive
length of Columns, Beams, Floor/Roof members, and Wall Panels, allow lengths to
be broken out and removed
Metal Connectors and Miscellaneous Materials
Multi-view
Orthographic views of
Connector
Details and master legend
Neoprene
Bearing Pad Details
Reinforcing
Bar Schedule
Letter
designation, Bar type, Bending dimension
When
combined with the Engineering Drawings, placed as the first sheet
Precast
Concrete Bill of Materials
Definition
and Purpose
List
of all materials used in the fabrication and erection of precast concrete
products
Several
Procedures
One
complete Bill of Materials covering all members of the job
Individual
and independent Bill of Materials for each individual member in the job
One
Bill of Material for each separate type of product used on the job
The
most popular, same purpose as first two, more efficient
Bill
of Materials list the following
Type
of Product
The
mark numbers for all members of a product
All
members contained in the members
Quantity
of each type of material
Totaled
by product type
Totaled
again for entire job
Constructing
Bill of Materials
Prepared
from Fabrication Details
Counting
Material Quantities
Determined
from dimensions for the materials not the pictures of the material