SEISMIC BRACING SUPPORT SYSTEM

Recent events around the globe have highlighted the need for consideration around the seismic restraining of support systems in construction and industry. The Unistrut seismic catalogue information shows how certain existing support systems can be seismically retrofitted, and gives guidelines around new installations.

RIGID & CABLE BRACE FACTORS

Single Rigid Brace

BRACE SLOPE SLOPE FACTORS
RISE RUN Kb Kx Ky
1 : 1 1.414 1.000 1.000
1 : 2 1.118 1.000 0.500
1 : 3 1.054 1.000 0.333
1 : 4 1.031 1.000 0.0250

Two Opposing Cable Braces

BRACE AXIAL FORCE

±Fb = Kb * Fh (Rigid Brace – Tension & Compression)
+Fb = Kb * Fh (Cable Brace – Tension only)
     Kb = Brace Factor
     Fh = Horizontal Seismic Factor
Fy = Ky * Fh
Fx = Kx * Fh

4-Way Splayed Patterns

BRACE SLOPE SLOPE FACTORS
RISE RUN Kb Kx Ky
1 : 1 2.000 1.000 1.000

BRACE AXIAL FORCE

Fb = Kb * 1/2 Fh = 2.000 * (1/2 Fh)
Fb = Fh (Tension only)
    Kb = Brace Factor
    Fh = Horizontal Seismic Factor
Fy = Ky * Fh
Fx = Kx * Fh

TRAPEZE LOAD DATA

Wire Bracing on Trapeze


P1000 Trapeze Load Data
SPAN
mm
SWL UNIFORM DESIGN LOAD*
kN
CONCENTRATED LOAD @ CENTER OF SPAN
N
500 7.42 2.000
1000 3.71 2.490
1250 2.94 1.870
1500 2.67 1.510
2000 1.85 1.250
2250 1.65 1.070
2500 1.48 930
2750 1.35 850
3000 1.24 760
P5500 Trapeze Load Data
SPAN
mm
SWL UNIFORM DESIGN LOAD*
kN
CONCENTRATED LOAD @ CENTER OF SPAN
N
500 13.84 7.210
1000 6.92 4.800
1250 5.54 3.600
1500 4.61 2.920
2000 3.46 2.400
2250 3.08 2.050
2500 2.77 1.780
2750 2.52 1.600
3000 2.31 1.420

P1000 Trapeze Load Data
SPAN
mm
SWL UNIFORM DESIGN LOAD*
kN
CONCENTRATED LOAD @ CENTER OF SPAN
N
1200 10680 5290
1500 8450 4230
1800 7120 3510
2000 6090 3020
2500 5340 2620
2750 4760 2360
3000 4270 2090
P1000 Trapeze Load Data
SPAN
mm
SWL UNIFORM DESIGN LOAD*
kN
CONCENTRATED LOAD @ CENTER OF SPAN
N
1200 20820 10630
1500 17210 8540
1800 14320 7120
2000 12280 6050
2500 10760 5290
2750 9560 5160
3000 8590 4230

TRAPEZE PIPE CLAMPS

P2024 Series Pipe Clamps

 
UNISTRUT PART NUMBER PART SIZE mm STRAP THICKNESS mm SCREW SIZE mm VERTICAL FORCE N TRANSVERSE FORCE N LONGITUDINAL FORCE N
P2026 14 1.6 6 1780 310 220
P2028 19 1.6 6 2670 440 310
P2030 25 1.6 6 2670 670 360
P2032 32 2.0 6 2670 670 670
P2034 38 2.0 6 3560 1070 670
P2038 51 2.5 8 3560 1070 890
P2042 64 2.5 8 3560 1070 890
P2046 76 2.5 8 3560 1070 890
P2050 90 2.5 8 4450 1420 890
P2054 102 2.5 8 4450 1420 890
P2062 127 2.5 8 4450 1420 890
P2070 152 2.5 8 4450 1420 890
P2070-80 203 2.5 8 4450 1420 890

UN4/UN15 Series

 
UNISTRUT PART NUMBER PART SIZE mm STRAP THICKNESS mm SCREW SIZE mm VERTICAL FORCE N TRANSVERSE FORCE N LONGITUDINAL FORCE N
UN4-19 19 3 8 2220 1110 440
UN4-25 25 3 8 2220 1110 440
UN4-32 32 3 8 2220 1110 440
UN4-38 38 3 8 2220 1110 440
UN4-51 51 6 12 4450 4450 890
UN4-60 60 6 12 4450 4450 890
UN15-76 76 6 12 4450 4450 890
UN15-89 89 6 12 4450 4450 890
UN15-102 102 6 12 4450 4450 890
UN15-127 127 6 12 4450 4450 890
UN15-152 152 6 12 4450 4450 1220

SINGLE PIPE CLAMPS & Bracing

Steel Pipe Clamp


Design Longitudinal Force

PAPER SIZE
m2
LONGITUDINAL FORCE
kN
12 thru 40mm 0.445
43 thru 127mm 0.890
152 1.670
203 2.220

HANGER ROD STIFFENERS/BRACING



Vertical Bracing or Stiffener Load Table

ROD SIZE
mm
ROOT AREA
m2
RADIUS OF GYRATION
mm
MAX ALLOWABLE ROD COMPRESSION ROD STRESS AT 50% 4,500PSI DESIGN LOADS ROD STRESS AT 75% 6,750PSI ROD STRESS AT 100% 9,000PSI MAX SEISMIC SAFE LOAD
10 0.068 0.314 610 350 300 250 810
12 0.012 0.425 1130 500 400 350 1500
16 0.202 0.536 1810 600 500 400 2410
20 0.302 0.625 2710 750 600 500 3610
24 0.419 0.73 3770 900 700 650 5030

Assumptions
1. Rod held against translation at location of cradle clips K equals 1.0.
2. L = Distance between connection points.
3. Trapeze with braces on alternate members.
*4. Loads are based on the root area of the thread and at a stress of 9,000 psi, 62 mpa.
*5. Safe seismic forces are determined by increasing allowable safe loads by 33%

P2486 Seismic Rod Stiffener

PART NO. FINISH SIZE WEIGHT
P2486 EG 10mm thru 16mm 16

CHANNEL STYLES

P1000

P5500

P1001

P5501

P1000T

CHANNEL NUTS & HARDWARE

Spring Nut
P1006
P1008
P1010

Spring Nut
P1012S

Nut Without Spring
P3006
P3008
P3010

Nut Without Spring
P1012

Hex Head Cap Screw
HHS

Coupler Nut
RC

Hex Nut
HN

Lock Washer
SW

Flat Washer
FW

CHANNEL FITTINGS

P2815
Adjustable Brace

P1843W
Adjustable Hinge

P2785
Beam Clamp

Series SPF100
Fitting

Series SPF200
Adjustable Fitting

Series SPF300
Fitting

Series
SPF400

P2452
Knee Brace

P2095 to
P1546

P2101 &
P2103

P2106 to
P1186

STRUCTURE ATTACHMENTS

Wood

Steel

Concrete

TYPICAL ATTACHMENTS


STRUCTURE ATTACHMENTS


P3300 Series Concrete Inserts

NOTE:
Recommended loading on inserts in 20 mpa concrete. Sufficient concrete must surround inserts to conform to design sheer stress. The distance between the insert centerlline and the concrete edge must be a minimum of 75 mm.

Values in the Table are based on a safety factor of 3 to 1. For installation in Hospitals, use 65% of tabulated values. When installing underside of slab, use 50% of tabulated values.

ENERGYNET