Design of Steel Portal Frame for Single-Story Structures

This article provides guidance on the design of steel portal frames for single-story structures, including the use of cold formed steel I sections. It covers various aspects of the design process, including concept design, structural elements, roof design, beam design, column design, cladding installation, access door design, and connection design. The article also includes calculations and assumptions for reinforced concrete wall design.

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1.0 INTRODUCTION
It is evaluated that half of all constructional steelwork utilized in the UK is in the essential
structure of single-story structures. Inside this significant market division, the steel portal frame
has turned into the most widely recognized auxiliary shape in pitched rooftop structures, in light
of its economy and adaptability for a wide scope of ranges(Shaw 2013). In spite of the fact that
the utilization of steel portal frame is settled in the UK, there is no production which characterizes
best practice in this type of development. The direction in this production focuses on the structure
of single-span portal frame utilizing cold formed steel I areas, however the general standards
additionally apply to multi-range portal frames and to the utilization of manufactured segments.
Where conceivable, the direction given has been concurred with fashioners, steelwork temporary
workers and those worried about checking for building control purposes(Papadopoulos, Soimiris
and Papadrakakis 2013).
It manages the issues that happen sensibly frequently in configuration practice and which are
agreeable to general direction. Perspectives required for idea or primer configuration are secured
first, trailed by more subtleties for definite plan. Auxiliary components, for example, purlins, end
peaks and cladding are additionally assessed. The utilization of PC configuration has made
manual computations nearly repetitive for normal portal frames, and in this manner point by point
direction on manual techniques for examination is excluded. Be that as it may, tables and graphs
for starter configuration are displayed, and reference is made to different distributions for manual
examination systems.
Yield from the CSC Fastrak program is incorporated into Supplement D, as this program is
broadly utilized by steel fabricators in the UK. Where direction is given in detail somewhere else,
for instance on the plan of entry outlines in flame limit conditions, built up productions are

alluded to, with a concise clarification and survey of their substance. Cross-reference is made to
the pertinent conditions of BS 5950-1:2000[1]. The alteration of BS 5950-1 from the 1990
adaptation to the 2000 rendition gave ascend to some specialized changes that influence the
structure of portal frames. Too, statements were renumbered in the 2000 form. The primary
design that effect point by point structure of portal frame are as per the discussion.
2.0 Scope of the work
This particular work was limited to the design of the portal frame structure that has various
functional characteristics and subsequent analysis of the performance of these components.
3.0 Structure design
3.1 Overall Analysis of portal frame
The portal frames are generally regarded as low-rise structures that are made of columns and
rafters that are horizontal which are connected by the moment-resisting connections. The frame
actually relies on the bending resistance of the very connections. These connections are stiffened
by a favorable haunch or sections that are deepened. This leads to the formation of the rigid frame
that constitutes the structure. The frames are actually stable in their own plane and assist in the
provision of the clear plan. Various sorts of structure can be characterized comprehensively as
entrance outlines.
These are depicted quickly in this section; however the consequent Sections of this production
focus on the structure of single-range symmetric portal frame. All the casing types portrayed can
be intended for a scope of base fixity; determination of fitting fixity is an imperative structure
choice. Ostensibly stuck base is the most widely recognized for comfort of establishment
structure and development. It may not give the most financial aggregate answer for establishment

and structure in light of the fact that even unassuming base solidness regularly gives real
enhancements in casing dependability. The data given with respect to ranges, rooftop pitch, and
so forth is run of the mill of the structure that are represented.
3.2 Roof Design
A portal frame that has been designed will basically have a pitched roof with the following
dimensions
A span that ranges between 50-60m
Height of the eaves as 10m
Roof pitch as 6 degrees
Frame spacing was taken as 5 m
Having haunches in the rafters at the apex and eaves.
3.3 Beam design

Ag = 12 x 0.75 + (16 - 0.75 - 1.0) x 0.5 + 15 x 1.0 = 31.125 in2
Af1 = 12 x 0.75 = 9 in2
Af2 = 15 x 1.0 = 15.0 in2
Aw = 0.5 x (16 - 0.75 - 1.0) = 7.125 in2.
Distance from elastic centroid from bottom =y
= 6.619 in. 31.125 9 (16 0.75/ 2) 7.125 8.125 15 0.5
= Ix = 12×0.753 /12 + 9.0×9.0062 + 0.5×14.253 /12 + 7.125×1.5062 + 15.0×13 /12 + 15×6.1192
= 1430 in4
Sx = Ix / (16-6.619) = 152.43 in3
My-x = Fy Sx = 7621.8 kip-in. = 635.15 kip-ft

3.4 Universal column design
In a building, sections assume to a great degree huge job. Sections are the vertical help
individuals to which the different components, for example, pillars, pieces and dividers are
unbendingly associated. Disappointment of the section can prompt the fall of the whole structure.
In a confined structure, where the sections are inflexibly associated with other basic components,
other than the immediate loads substantial twisting minutes are forced on the segments.
Expected load = 14  6 [0.925 ×1.35 × 0.9 + 1.5 × 0.5 × 0.6] = 132.2 kN
Total roof loading = 8  132.2 = 1058 kN

Equivalent horizontal force (acting as a point load) at roof level in end frame = 0.5  0.5% 
1058 = 2.7 kN gk = 0.9 kN/m2 qk = 0.6 kN/m2 (see arrangement and actions)
Resultant horizontal force at roof level = 2.7 kN 5.3.2(3)
Floor loading on one column = 14  6 [0.925 ×1.35  3.7 + 1.5 × 0.7 3.3] = 679 kN
Total floor loading = 8  679 = 5433 kN
Equivalent horizontal force (acting as a point load) at each floor level in end frame = 0.5  0.5%
 5433 = 13.6 kN.
13.6KN>12.97 thus OK.
3.5 Cladding of wall installation
Liner sheets are generally made from chilly shaped pre-covered steel or aluminum and have a
shallow trapezoidal profile, i.e. a stature 18mm to 20mm as delineated underneath. For steel
liners, the sheet thickness is generally either 0.4mm or 0.7mm, while aluminum liner sheets are
marginally thicker at 0.5mm or 0.9mm. The decision of liner will rely upon the required crossing
ability, the cladding establishment technique and the acoustic prerequisites of the cladding. Where
required, the acoustic execution of the cladding, specifically its capacity to retain sound and limit
resonation, might be upgraded by the utilization of a punctured liner sheet(Narayanan 2014).
The shallow liner sheets are not sufficiently able to stroll on, so it is basic that the protection,
spacer framework and climate sheet are introduced from sheets or access stages, as showed
beneath. Notwithstanding, they do give a non- delicate boundary against falling once they have
been completely secured. Where strolling access is required, usually practice to supplant the

shallow liner profile with an increasingly considerable sheet, i.e. 32mm to 35mm trapezoidal
profile in 0.7mm measure steel.
3.6 Design Of Access Door
The access door will have dimensions of double 1000x2045.This will be equivalent to dimension
of two room doors.
4.0 Connections Design
4.1 Connection of roof panel to Formed steel
Permanent actions
Self weight of roof construction 0.75 kN/m2 Self weight of services 0.15 kN/m2 Total permanent
actions 0.90 kN/m2
Variable actions
Imposed roof load 0.60 kN/m2 Total imposed action 0.60 kN/m2
Partial factor for permanent actions G = 1.35 Partial factor for variable actions G = 1.5
Reduction factor  = 0.925

Reaction force at support A RA =2  Fd = 87.8 kN
At joint A FAB  sin15o + (RA-W/2) = 0 FAB  cos15o + FAC = 0 FAB = –255 kN FAC =
246 kN .
At joint B FBC + W  cos15o = 0 FBD - FAB - W  sin15o = 0 FBC = –42 kN FBD = –243 kN
At joint C FBC  sin75o + FCD  sin30o = 0 FCE – FAC - FBC  cos75o + FCD  cos30o = 0
FCD = 82 kN FCE = 164 kN.
4.2 Connection of cold formed steel to main beam
Vertical shear resistance of the composite beam is:  3 M0 v y pl,Rd pl,a,Rd  A f V V  BS
EN 1993-1-1 6.2.6(3) For rolled I and H sections loaded parallel to the web: A 2bt t   t 2r v  
f  f w  but not less than w h t 2800 (2 101.6 6.8) 6.8 5.7 (2 7.6) Av         Av
1560 mm2  1.0 (Conservatively from note to 6.2.6(3)) h wt w 1.0  240.4  5.7 1370
mm2 1560 mm2 > 1370 mm2 Therefore, Av 1560 mm2 10 247 3 1.0 275 1560 -3 pl,Rd   
V   kN Design vertical shear resistance Vpl,Rd = 247 kN 0.31 247 76.5 pl,Rd Ed   V < 1.0
In this way the plan protection from vertical shear is satisfactory. Structure opposition for vertical
shear is sufficient 6.2.2.4 As there is no shear compel at the purpose of most extreme bowing
minute (mid range) no decrease (because of shear) in bowing obstruction is required.
4.3 Beams to Column

Bolt details
Tensile stress area of bolt As = 245 mm2 Diameter of the holes d0 = 22 mm Diameter of the
washer dw = 37 mm Yield strength fyb = 640 N/mm2 Ultimate tensile strength fub = 800 N/mm2
3.5, Table 3.3 Limits for locations and spacings of bolts End distance e1 = 55 mm Minimum =
1.2do = 1.2 × 22 = 26.4 mm < 55 mm, OK Edge distance e2 = 50 mm Limits are the same as
those for end distance. Minimum = 1.2do = 1.2 × 22 = 26.4 mm < 50 mm, OK Spacing (vertical
pitch) p1 = 85 mm Minimum = 2.2do 2.2d 0  2.222  48.4 mm < 85 mm, OK 14t p 1410
140 mm > 85 mm Spacing (horizontal gauge) p3 = 100 mm Minimum = 2.4do 2.4d 0  2.422
 52.8 mm < 100 mm, OK
4.4 Connection of secondary to main beam

4.5 Connection of column to base plate and pad footing
It is expected that the pivotal power is exchanged by direct bearing, which is accomplished by
typical manufacture forms. Just ostensible welds are required to interface the baseplate to the
segment, however practically speaking full profile 6mm filet welds are regularly utilized(Saa,
Garcia, Gomez, Carretero and Garcia 2012).

5.0 Foundation Design
5.1 Reinforced Concrete Wall Design
Assumptions made
1. The out-of-plan moment is neglect able.
2. The type of wall is an exterior wall.

5.2 Design of Slab
Floor slab and material properties
Total depth of slab h = 130 mm
Corus profiled steel sheeting CF60
Thickness of profile t = 1.0 mm
Depth of profile hp = 60 mm
Span L = 3 m
Effective cross-sectional area of the profile Ape = 1424 mm2 /m
Second moment of area of the profile Ip = 106.15 cm4 /m
Yield strength of the profiled deck fyp = 350 N/mm2 from manufacturer’s data:
Design value of bending resistance (sagging) MRd = 11.27 KNm/m
Height of neutral axis above soffit: = 30.5 mm BS EN 1992-1-1
Normal concrete strength class C25/30
Density (normal weight, reinforced) 26 kN/m³ (wet) 25 kN/m³ (dry)
[These density values may vary for a specific project depending on the amount of steel
reinforcement.] Cylinder strength fck = 25 N/mm2
Modulus of elasticity Ecm = 31 kN/mm2
Actions

Concrete weight Self weight of the concrete slab
(volume from decking manufacturer’s data)
0.097 × 26 × 10-6 = 2.52 kN/m2 (wet)
0.097 × 25 × 10-6 = 2.43 kN/m2 (dry)
Permanent Actions
Construction stage kN/m2
Steel deck 0.11
Total 0.11
Composite stage kN/m2
Concrete slab 2.43
Steel deck 0.11
Ceiling and services 0.15
Total 2.69
Construction stage: gk = 0.11 kN/m2
Composite stage: gk = 2.69 kN/m2
Variable actions
At the construction stage, the loading considered is a 0.75 kN/m² load across the entire slab, with
an additional 0.75 kN/m² load across a 3 m span, which can be positioned anywhere on the slab

span. In this case the span is 3 m, and so the construction loading across the whole span is 1.50
kN/m²
Construction stage kN/m2
Construction loading
(1) Outside the working area 0.75
(2) Inside the working area (additional) 0.75
(3) Concrete slab 2.52
Total 4.02
Composite stage kN/m2
Imposed floor load 3.30 (See structural arrangement and loading)
Construction stage: qk = 4.02 kN/m2
Composite stage: qk = 3.30 kN/m2
Ultimate Limit State (ULS)
(B) Partial factors for actions
Partial factor for permanent actions G = 1.35
Partial factor for variable actions  Q = 1.5
Reduction factor  = 0.925
Combination of actions at ULS

In this example, the use of expression 6.10b is demonstrated. Design value of combined actions =
Gg k Qq k

5.3 Foundation Selection
The foundation selection of the portal frame was guided by the following factors:
Building weight. The establishments have been intended to oppose elevate powers coming about
because of a generally light structure. On the off chance that the real structure is heavier (e.g.,
from the utilization of solid composite siding or steel encircling), it might be financially cheaper
to reanalyze and update the footings. This is especially valid for a home that shouldn't be raised in
excess of a few feet or then again has short establishment dividers that can enable oppose to
elevate.

Footprint multifaceted nature. By need, the establishments have been intended for generally
straightforward rectangular impressions. On the off chance that the real impression of the portal
frame is generally intricate, the specialist may need to consider torsional wind stacking,
differential development among the "modules" that make up the home, amassed stacking in the
home's floor and rooftop stomachs, what's more, shear divider situation(Chen, Chui, Ni and Xu
2013).
Local soil Conditions
The heap establishments have been produced for moderately delicate subsurface soils. For driven
treated timber heaps, the possible suitable working burden esteems of 7 tons for each heap
gravity, 4.65 tons per heap elevate, and 2 tons for every heap sidelong were utilized. For steel
pipe heaps, the possible passable working burden heaps were more prominent (10 tons for each
heap for gravity stacking, 6.7 tons per heap for inspire, and 4 tons for each heap for sidelong
stacking). Soil testing on the site ought to likewise be considered to approve the suppositions
made. Shallow foundation was thus chosen with the application of padding footing system.
5.4 Design of Pad footing system

Details of the foot pad
Pad footing details Length of pad footing; L = 2500 mm Width of pad footing; B = 1500 mm
Area of pad footing; A = L × B = 3.750 m2 Depth of pad footing; h = 400 mm Depth of soil over
pad footing; hsoil = 200 mm Density of concrete; ρconc = 23.6 kN/m3.
Calculation of pad base reaction
Total base reaction; T = F + PA = 415.4 kN
Eccentricity of base reaction in x; eTx = (PA × ePxA + MxA + HxA × h) / T = 94 mm
Eccentricity of base reaction in y; eTy = (PA × ePyA + MyA + HyA × h) / T = 142 mm
Confirmation of pad base reaction eccentricity abs(eTx) / L + abs(eTy) / B = 0.132 Base reaction
acts within combined middle third of base (Phan et al 2013)
Calculation of pad base pressures
q1 = T / A - 6 × T × eTx / (L × A) - 6 × T × eTy / (B × A) = 22.880 kN/m2 q2 = T / A - 6 × T ×
eTx / (L × A) + 6 × T × eTy / (B × A) = 148.747 kN/m2 q3 = T / A + 6 × T × eTx / (L × A) - 6 ×

T × eTy / (B × A) = 72.800 kN/m2 q4 = T / A + 6 × T × eTx / (L × A) + 6 × T × eTy / (B × A) =
198.667 kN/m2
Minimum base pressure; qmin = min(q1, q2, q3, q4) = 22.880 kN/m2
Maximum base pressure; qmax = max(q1, q2, q3, q4) = 198.667 kN/m2
6.0 Hard Standing Area
6.1 Pavement Design
The design of the pavement took into consideration the following variables
(a) CBR (with respect to standard proctor) :
Subgrade = 4
Percentage of 95% compaction
(b) Data from the field :
(i) Number. of commercial vehicles per day (in both directions), A = 300
(ii) Yearly growth rate of commercial traffic r = 10 percent
(iii) Design life of the pavement, x = 12 years

6.2 Footway Design
The dimensions of the footways will be 2.00m for maximum width
There will be no kerbsMaterial to be used will be Block paving

.6.3 Car Park Arrangement
Minimum Dimensions for heavy vehicle parking
Items Rigid-framed
vehicles of length
< 7.5m
a) Parking stall:
Rigid-framed
vehicles of length
> 7.5m
Articulated vehicles
(eg. prime movers,
20',40' & 45'
trailers)
- Parallel parking
- Angled parking
9.3m x 3.0m
7.5m x 3.0m
14.0m x 3.3m
12.0m x 3.3m
19.0m x 3.3m
14.0m x 3.3m
b) Width of parking 1-Way 2-Way 1-Way 2-Way 1-Way 2-Way
aisle: Flow flow flow flow Flow Flow
- Parallel parking 3.6m 7.4m 4.5m 7.4m 4.5m 7.4m
- 30 0 -parking 3.6m 7.4m 4.5m 7.4m 7.0m 7.4m
- 45 0 -parking 5.0m 7.4m 5.5m 7.4m 9.5m 9.5m
- 60 0 -parking 6.5m 7.4m 7.0m 7.4m 11.0m 11.0m
- 90 0 -parking 9.0m 9.0m 11.0m 11.0m 12.0m 12.0m
c) Width of
Access way
-On Straight
- On Curve
1-way traffic
flow: 4.5m;
2-way traffic
flow: 7.4m
5.5m per lane
1-way traffic
flow: 4.5m
2-way traffic
flow:7.4m
7.5m per lane
1-way traffic flow:
4.5m
2-way traffic flow:
7.4m
9.0m per lane
(6.0m for 20' trailer)
d) Inside turning
radius of curve
e) Maximum gradient of
ramp:
- Straight ramp
6.0m 6.0m 6. 0m
- Curved ramp 1:12
1:15
1:12
1:15
1:15
1:20
f) Headroom
clearance
4.2m 4.2m
(exclude
double -
decker)
4.5m
(4.75m at ramps

6.4 Goods Unloading Area
This will be located at a specific area opposite cushion shatters.
7.0 Drainage design
7.1 Rainfall analysis
Data collection of rainfall
There is diverse precipitation of every single place in various states. This normal yearly
precipitation has been considered for completing appraisal of Water Collection. The average
rainfall will be taken as 880mm
Coefficient of the roof
The material used here is galvanized sheet that has coefficient of 0.9

7.2 Surface runoff estimation
The formula indicated below will be used in the estimation of surface runoff.
In which Q is equivalent to runoff (in) P refers to the precipitation (maximum potential runoff)
(in) S = potential maximum watershed retention (in) and finally Ia = Initial abstraction (in).
7.3 Pipe design
7.4 Collection point

The assessment of the collection of the rainwater will include the use of three parameters
Water from the roof=Total area of the roof*Average rainfall*coefficient of the runoff. The
collection from the roof will be achieved by the use of the gutter.
Tank capacity
The estimation of the capacity of the tank will be as per the water collected from the roof
top .This can be approximated as 1000litres following the roof area.
7.5 Discharge point
The tank for storage will have overflowing tap that will be located at the top region. This pipe
will drain water to the drainage pipe that is connected to the sewer and toilet waterline.
8.0 Conclusion
The design of portal frame employed scientific calculation with the required dimensions.
References were made to the standard available records and data. The decision of liner will rely
upon the required crossing ability, the cladding establishment technique and the acoustic
prerequisites of the cladding. Where required, the acoustic execution of the cladding, specifically
its capacity to retain sound and limit resonation, might be upgraded by the utilization of a
punctured liner sheet.

REFERENCES
Chen, Z., Chui, Y.H., Ni, C. and Xu, J., 2013. Seismic response of midrise light wood-frame
buildings with portal frames. Journal of Structural Engineering, 140(8), p.A4013003.
Narayanan, R. ed., 2014. Steel-concrete composite structures. CRC Press.
Papadopoulos, V., Soimiris, G. and Papadrakakis, M., 2013. Buckling analysis of I-section portal
frames with stochastic imperfections. Engineering Structures, 47, pp.54-66.
Phan, D.T., Lim, J.B., Sha, W., Siew, C.Y., Tanyimboh, T.T., Issa, H.K. and Mohammad, F.A.,
2013. Design optimization of cold-formed steel portal frames taking into account the effect of
building topology. Engineering Optimization, 45(4), pp.415-433.
Saa, R., Garcia, A., Gomez, C., Carretero, J. and Garcia-Carballeira, F., 2012. An ontology-
driven decision support system for high-performance and cost-optimized design of complex
railway portal frames. Expert Systems with Applications, 39(10), pp.8784-8792.
Shaw, W.A. ed., 2013. Developments in Theoretical and Applied Mechanics: Proceedings of the
Third Southeastern Conference on Theoretical and Applied Mechanics. Elsevier.