TR.20.9 Applying Fireproofing on members
STAAD.Pro includes a method to automatically consider the weight of fireproofing material applied to structural steel.
General Format
MEMBER FIREPROOFING
member-list FIRE { BFP | CFP } THICKNESS f1 DENSITY f2
Where:
| Parameter | Description |
|---|---|
| THICKNESS f1 | thickness (T in the figures below) in length units |
| DENSITY f2 | density of fireproofing material in (force / length3) units |
In the actual load case itself, nothing besides the SELFWEIGHT command is necessary to instruct the program to include the weight of the fireproofing material in the selfweight calculation.
Two types of fireproofing configurations are currently supported. They are:
- block fireproofing
- contour fireproofing
Block Fireproofing (BFP)
The following figure shows this configuration. The fire-protection material forms a rectangular block around the steel section.
The area of fireproofing material (Afp) at any section along the member length is calculated in the following manner.
For Wide Flanges (I-shaped sections), Channels and Tees,
Afp = [(Bf + 2T)*(D+2T)] - Asteel
For single angles,
Afp= [(Bf + 2T)*(D+2T)] - Asteel
where| = | ||
| = | ||
| = | ||
| = |
Where:
Block fireproofing (BFP) on various shapes
Contour Fireproofing (CFP)
In this configuration, the fire-protection material forms a coating around the steel section as shown in the next figure. The area of fireproofing material (Afp) for this case is calculated in the following manner.
For Wide Flanges (I-shaped sections)
Afp = [(Bf + 2T)*(Tf+2T)]*2 + [(D-2T-2Tf)*(Tw+2T)] - Asteel
For single angles,
Afp = [(L1+2T)*(2T+Ta) + (L2-Ta)*(2T+Ta)] - Asteel
For Tees,
Afp = [(Bf + 2T)*(Tf+2T)] + [(D-Tf)*(Tw+2T)] - Asteel
where| = | ||
| = | ||
| = | ||
| = | ||
| = | ||
| = | ||
| = |
Contour fireproofing (CFP) on various shapes
- the type of fireproofing
- the thickness T shown in the above figures
- the density of the fireproofing material
- the members on which it is to be applied
For each such member, Afp is calculated and multiplied by the density of the fireproofing material to obtain the weight per unit length of the member. This is added to the weight per unit length of the steel section itself and the total is used in calculating selfweight. Hence, SELFWEIGHT must be one of the load components of load cases if the weight of the fireproofing material should be considered as part of those load cases.
Notes
-
STAAD calculates the fire proofing weight only for the following sections:
For block fireproofing - I-shaped sections like those from the built-in tables (American W,S,M,HP, British UC and UB, etc.), tapered I shaped sections, single channels, angles and Tees.
For CFP-contour fireproofing - the sections are I-beam straight or tapered, angle, Tee.
I-shaped sections like those from the built-in tables (American W,S,M,HP, British UC and UB, etc.), tapered I shaped sections, angles and Tees..
-
Fire proofing weight is not calculated for the following section types: Pipe, tube, composite I beams with slab on top, double channel, double angle, HSS, I-beam with cover plates, prismatic, solid circle or rectangle, castellated, cold formed sections, wood, aluminum, tapered poles, etc.
Example Problem
STAAD SPACE
UNIT KIP FEET
JOINT COORDINATES
1 0. 0. ;2 0. 15. ; 3 20. 15. ;4 20. 0.
MEMBER INCIDENCE
1 1 2 ; 2 2 3 ; 3 3 4
MEMBER PROPERTY AMERICAN
1 3 TABLE ST W12X26
2 TABLE ST W14X34
CONSTANTS
E STEEL ALL
POISSON STEEL ALL
DENSITY STEEL ALL
SUPPORT
1 FIXED ; 4 PINNED
UNIT POUND INCH
MEMBER FIREPROOFING
1 3 FIRE BFP THICK 2.0 DENSITY 40
2 FIRE CFP THICK 1.5 DENSITY 40
UNIT KIP FT
LOADING 1 DEADWEIGHT OF STEEL + FIREPROOFING
SELF Y -1.0
LOAD 2 LIVE
MEMBER LOAD
2 UNI GY -0.8
LOAD COMBINATION 3
1 0.75 2 0.75
PERFORM ANALYSIS
PRINT MEMBER FORCES
PRINT SUPPORT REACTIONS
FINISH