The objective of the report is to enhance the design of a warehouse building. The analysis of a structure is essential as the reliability quality of the structure is explored. Can the building withstand the loading conditions? That is the issue solicited amid most from the investigation. The structural investigation is basic since it distinguishes the basic parts that need extraordinary consideration. Moreover, the analysis comprehends the plan of the structure in more detail. All aspects of the structure has a reason and this ought to be recognized before any alterations are made.
The location of the site is located along Beaconsfield street, and also be accessed through O’Riordan street or Doody street as demonstrated.The structure to be dissected is a warehouse building used to store cultivating gear and items. The building encounters a great stresses on different parts being applied by several load conditions. It is not possible to do an analysis of the whole building at once. Therefore, for a comprehensive analysis the structure is sub divided into portions for easier analysis. Additionally, unique parts of the building serve more imperative parts than others. In this report the roof truss, joints and column support are thought to be the most essential parts.
Steel schedule
|
Properties
|
|
Section
|
Number
|
Length (ft)
|
Total length
|
Weight/length
|
Total weight of steel (pounds)
|
|
W 14 X 132
|
2
|
30
|
60
|
132
|
7920
|
|
W 14 X 120
|
2
|
40
|
80
|
120
|
9600
|
|
W 16 X 40
|
7
|
30
|
210
|
40
|
8400
|
|
W 27 X 94
|
2
|
40
|
80
|
94
|
7520
|
|
W 18 X 50
|
5
|
40
|
200
|
50
|
10,000
|
|
W 14 X 43
|
2
|
30
|
60
|
43
|
2580
|
|
W 18 X 84
|
9
|
25
|
225
|
84
|
18,900
|
|
W 14 X 109
|
12
|
25
|
300
|
109
|
32700
|
|
W 24 X 68
|
2
|
44
|
88
|
68
|
5984
|
Cost
|
Properties
|
|
Section
|
Number
|
Length (ft)
|
Total length
|
Cost per length
|
Total cost
|
|
W 14 X 132
|
2
|
30
|
60
|
$50
|
$3000
|
|
W 14 X 120
|
2
|
40
|
80
|
$46
|
$3680
|
|
W 16 X 40
|
7
|
30
|
210
|
$28
|
$5880
|
|
W 27 X 94
|
2
|
40
|
80
|
$35
|
$2800
|
|
W 18 X 50
|
5
|
40
|
200
|
$30
|
$6000
|
|
W 14 X 43
|
2
|
30
|
60
|
$25
|
$1500
|
|
W 18 X 84
|
9
|
25
|
225
|
$40
|
$9000
|
|
W 14 X 109
|
12
|
25
|
300
|
$48
|
$14400
|
|
W 24 X 68
|
2
|
44
|
88
|
$38
|
$3344
|
Duration of completion
The schedule showing the site activities that will be carried out from the beginning to the end while specifying the number of days shows that a total of 303 days are fully required, for all the activities to be tackled.
|
S.No
|
Activity description
|
Duration in days
|
Comment
|
|
1
|
Quantity survey
|
7
|
|
|
2
|
Order material
|
5
|
|
|
3
|
Delivery and storage of material
|
25
|
For every shipment
|
|
4
|
Drawing preparation of the warehouse of structural steel
|
12
|
|
|
5
|
Preparation of the warehouse joist
|
12
|
|
|
6
|
Drawing preparation of warehouse deck
|
12
|
|
|
7
|
Drawing preparation of warehouse miscellaneous steel
|
12
|
|
|
8
|
Warehouse drawing approval structural steel
|
12
|
For every batch
|
|
9
|
Drawing approval of the warehouse joist
|
12
|
|
|
10
|
Approval of the warehouse deck
|
12
|
|
|
11
|
Drawing approval of the warehouse miscellaneous steel
|
12
|
|
|
12
|
Fabrication of the warehouse steel
|
15
|
For every lot
|
|
13
|
Fabrication of the warehouse joists
|
25
|
|
|
14
|
Fabrication of warehouse deck
|
25
|
|
|
15
|
Fabrication of the warehouse miscellaneous steel
|
10
|
|
|
16
|
Building of the warehouse structural steel including joist
|
25
|
For every sequence
|
|
17
|
Building of the warehouse deck
|
25
|
|
|
18
|
Building of warehouse of miscellaneous steel
|
20
|
|
|
19
|
Inspection of the warehouse and testing fabrications
|
20
|
|
|
|
Inspection of the warehouse and testing building
|
5
|
|
From the Intec steel warehouse, the clerk of work whom we got from the site, was not willing at the first instance to pay attention to our questions and request to acquire part of the documentation that he was holding, this was because more critical work was going on by the site workers and he was supposed to explain and countercheck on each progress throughout the site and at the same point he thought we are investigators, but later he agreed and allowed us to take photo for the floor plan and the plan connections plan, that comprises of roof truss connection, beam to column connections for both welding and bolts at all the joints.
The site was first visted on 20th August 2018, and a duration of approximately one hour was taken, we also visited the 28th August 2018 and approximately one hour too was taken by the group members. We were granted entry first by the security guard of the site, and directed as to the clerk of work who was also present in the site, who granted us permission to atleast learn on the site, we were able to see beam to column end plate connection, column base connection, roof truss and bracing and bracing connections.
The calculations involve in designing the core connection of the warehouse, which includes, beam to column end plate connection, column base connection, roof truss and bracing and bracing connections
Beam to column end plate connection
|
|
Ref
|
Calculations
|
Output
|
|
BS EN
1993-1-1
NA 2.4 (Gardner and Nethercot, 2011)
BS EN
10025-2
Table 7(REAL, Couto, Lopes and Rodrigues, 2010.)
BS EN
1993-1-1
NA 2.15
Access steel
document
SN013a-EN-EU
3.5, Table 3.3
Access Steel
document
SN014a-
EN-EU
BS EN
1993-1-1
6.1(1)
Table 2.1
BS EN
1993-1-8
NA 2.3
Table NA.1
Access Steel
document
SN018a-
EN-EU(Bureau, 2006.)
SN014a-
EN-EU
3.6.1 &
Table 3.4
Steel
document
SN014a-EN-EU(Bureau, 2006.)
3.6.1 &
Table 3.4
BS EN
1993-1-
8:2005 3.7
BS EN
1993-1-1
6.2.6(2)
Access Steel
document
SN014a-ENEU
3.6.1 &
Table 3.4
|
The initial size of the components of the connection
Column 254 × 254 × 73 UKC in S275 steel
Beam 457 × 191 × 82 UKB in S275 steel
For the beam, fy = 275 N/mm2; fu = 410 N/mm2;
hb = 460mm;
tw = 9.9mm; tf = 16mm
For the plate, fu = 410 N/mm2
VcRd = = 723 kN
Design shear force at ULS,VEd = 230 kN
Since 230 < 0.75 Vc,Rd , a partial depth endplate is proposed.
hb< 500 mm, so 8 or 10 mm endplate is proposed.
End plate depth is minimum 0.6 hb = 276 mm; propose 280 mm.
Take M20 bolts, number of bolts = 239/74 = 3.2
6 M20 bolts are proposed.
Bolt details
The bolts are fully threaded, non-preloaded, M20 8.8, 60 mm long.
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
Limits for locations and spacing of bolts
End distance e1 = 55 mm
Minimum = 1.2d0 = 1.2 × 22 = 26.4 mm < 55 mm, OK
Edge distance e2 = 50 mm
Limits are the similar as those for end distance.
Minimum = 1.2d0 = 1.2 × 22 = 26.4 mm < 50 mm, OK
Spacing p1 = 85 mm
Minimum = 2.2d0
2.2d0 = 2.2 *22 = 48.4 mm < 85 mm, OK
14tp = 14*10 =140 mm > 85 mm
Spacing on the horizontal gauge p3 = 100 mm
Minimum = 2.4d0
2.4d0 = 2.4*22 = 52.8 mm < 100 mm, OK
Weld design
For full strength “side” welds
Throat (a) 0.39 × tw
a 0.39 × 9.9 = 3.86 mm; adopt throat (a) of 4mm,
leg = 6 mm
Partial factors for resistance
M0 = 1.0
M2 = 1.25 (for shear)
M2 = 1.1 (for bolts in tension)Mu = 1.1
The partial factor for resistance Mu is used for the tying resistance.
Elastic checks are not appropriate; irreversible deformation is expected.
The connection should be ductile in order to satisfy design requirement that act as nominally pinned. For the UK, and based on SN014, the ductility requirement satisfies the end plate, which comply to the following conditions:
tp =
= = 12 mm
Since tp = 10 mm < 12 mm, ductility is ensured.
Bolts in shear
Assuming the shear plane passes through the threaded portion of the bolt, the shear resistance FV,Rd of a single bolt is given by:
FV,Rd =
Introducing a factor of 0.8 to allow for the presence of tension in the bolts.
For bolt class 8.8, take v = 0.6, therefore,
FV,Rd = = 75.2 kN
For 6 bolts, VRd,1= 6 × 75.2 = 451 kN
End plate in bearing
The bearing resistance of a single bolt, Fb,Rd is given by:
Fb,Rd =
For end bolts,
b =min( min(0.83;1.95;1.0) = 0.83
For inner bolts,
b =min(min (1.04 ; 1.95 ; 1.0)= 1.0
Therefore k1 = min(2.8
= min(2.8= minimum (4.66; 2.5) = 2.5
Therefore, for the end bolts,
Fb,Rd = = 136.1 kN
And for the inner bolts,
Fb,Rd = = 164.0 kN
The bearing resistance of the bolts
= 2 ×136.1 + 4 × 164 = 928 kN
Group of Fasteners
The shear resistance value = 75.2 kN this valueis less than the bearing resistance, to determine the resistance of the group of fasteners is equal to the number of fasteners multiplied by the small design resistance which we take 75.2 kN
Resistance of the group = 6 × 75.2 = 451 kN
Beam web in shear
Shear resistance is checked only for the area of the beam web connected to the end plate.
Vpl,Rd =
Introduction of 0.9 is used to calculate the plastic shear resistance of a plate
Vpl,Rd = = 396 kN
The design shear resistance of the connection is
396 kN, > 230 kN, OK
Tying resistance of end plate
Bolts in tension
The tension resistance for a single bolt is given
Ft,Rd =
K2 = 0.9
Ft,Rd = = 160.4 kN
For 6 bolts, Ft,Rd = 6*160.4 = 962 kN
|
VEd = 230 kN
Weld throat
thickness,
a = 4 mm
Leg = 6 mm
VRd,1 = 451 kN
VRd,2 = 928 kN
VRd,8 = 396 kN
NRd,u,1 = 962 kN
|
Column base connection
|
|
Ref
|
Calculations
|
Outcome
|
|
BS EN
1990-1-1
NA 2.2.3.2
Table NA
A1.2(B)
BS EN
1992-1-1
Table 3.1(Beeby and Narayanan, 2005)
BS EN
1992-1-1
NA 2
Table NA 1
BS EN
1992-1-1
NA 2
Table NA 1
BS EN
1993-1-8
6.2.5(4) (Gardner and Nethercot, 2011)
|
Design conditions for column
Characteristic force due to permanent action, FG,k = 466 kN
Characteristic force due to variable action, FQ,k = 416 kN
Ultimate Limit State (ULS)
Partial factors for actions
Partial factor for permanent action G = 1.35
Partial factor for variable action Q = 1.5
Reduction factor ξ = 0.925
Combination of actions for ULS
Design value of combined actions
NEd = 0.925 × 1.35 × 466 + 1.5 × 416 = 1206 kN
Column details
Serial size 254 × 254 × 73 UKC in S275 steel
Height of section h = 254.1 mm
Breadth of section b = 254.6 mm
Thickness of flange tf = 14.2 mm
Thickness of web tw = 8.6 mm
Cross sectional Area A = 93.1 cm2
Section perimeter = 1490 mm
Partial factors for resistance
MO = 1.0 M2 = 1.25
Base plate details
Strength of foundation concrete to be C25/30
( fck =30 N/mm2)
fcd =
=
= 17 N/mm2
Area required = = 70941 mm2
Effective area ≈ 4c2 + Section perimeter × c + section area
where c is the cantilever outstand of the effective area, as shown
below.
70941 = 4c2 + 1490c + 9310
Solving, c = 37.6mm
=
=
= 112.9 > 37.6 mm
Therefore there is no overlap between the
Flanges
Thickness of base plate (tp)
tp = = 16.2 mm
tp < 40, therefore nominal design strength = 275 N/mm2.
Adopt 20mm thick base plate in S275 material
Connection of base plate to column
Assuming the axial force to be transferred by direct bearing, this is achieved through normal fabrication processes. Nominal welds are needed in connection of the baseplate to the column, where in a full profile 6mm fillet welds are always considered.
|
Axial force
NEd = 1206 kN
fcd = 17 N/mm2
tp = 20 mm
|
Roof Truss
|
|
Ref
|
Calculations
|
Outcome
|
|
BS EN 1991-
1-1
Tables 6.9 &
6.10
NA 2.2.3.2
Table
NA.A1.2(B)
6.1(1)
NA 2.15
NA 2.4
BS EN
10210-1
Table A3(Brettle and Brown, 2009)
Eq.(6.10) for
Class 3
Sections
BS EN 1993-
1-1
NA 2.23
|
The truss that is designed supports a roof that is only accessible during a normal maintenance and repair. The truss has a span of 14 m and also having 15° pitch. The imposed roof load due to snow obtained from BS EN 1991-1-3 is less than 0.6 kN/m2, therefore the characteristic imposed roof load is taken from BS EN 1991-1-1. The truss uses hollow sections for its tension chord, rafters, and internal members. The truss is fully welded.
Carrying out a truss analysis involves placing concentrated loads at the joints of the truss. At this point let us assume that the joints are pinned in the analysis and therefore only axial forces will carried by members.
Characteristic actions
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
Ultimate Limit State (ULS)
Partial factors for actions
Partial factor for permanent action G = 1.35
Partial factor for variable action Q = 1.5
Reduction factor ξ = 0.925
Design value of combined actions
= 0.925 × 1.35 × 0.9 + 1.5 × 0.6 = 2.02 kN/m2
Design values of combined actions on purlins supported by truss
For the distance of 3.5 m between purlins centre to centre
Design value = 2.02 *3.5/ cos150 = 7.32 kN/m
Design value of combined actions on truss
For a purlin span of 6 m
Fd = 7.32 * 6 = 43.92 kN
Truss analysis (due to forces Fd )
Reaction force at support A RA =2 *Fd = 87.8 kN
At joint A = FAB *sin150 + (RA-W/2) = 0
FAB * cos150 + FAC = 0
At joint B FBC + W*cos15o = 0
FBD - FAB - W *sin150 = 0
At joint C FBC *sin750 + FCD * sin300 = 0
FCE – FAC - FBC *cos750 + FCD *cos300 = 0
Partial factors for resistance
MO = 1.0
M1 = 1.0
M2 = 1.25
Design of Top Chords Maximum design force = 255 kN
(compression)
Try 100 * 100 * 5 square hollow section in S355 steel
Material properties:
modulus of elasticity E = 210000 N/mm2
steel grade S355 and thickness 16 mm
Yield strength fy = 355 N/mm2
= = 0.81
Section properties:
Depth and width of section h, b = 100 mm
Thickness t = 5 mm
Radius of gyration iz = 38.6 mm
Area A = 1870 mm2
Classification of the cross-section:
c = 100 – 3 × 5 = 85 mm
= 17
Class 3 limit = 42e = 42 × 0.81 = 34.
17 < 34, so the section is at least class 3
Compression resistance of the cross-section:
Nc,Rd = = = 663 kN
Therefore, the compressive design resistance is adequate.
Flexural buckling resistance:
Determine the non-dimensional slenderness for flexural buckling:
=
Where, Lcr = 1.0 *LAB = = 3623 mm
Therefore, λ1 = = = 76.4
= =
Determine the reduction factor due to buckling
X =
Where, 0.5[1 +
And
0.5[1 +
= 1.36
X =
= 0.52
Nb,Rd = = = 345 kN
Therefore, the design flexural buckling resistance of the selected
100 × 100 × 5 SHS is satisfactory.
Design of bottom chords
Maximum design force = 246 kN (in tension)
The bottom chord will also be a 100 × 100 × 5 SHS, S355. By inspection, the design tension resistance is equal to the design plastic resistance of the cross section.
Npl,Rd = = = 663 kN
663 kN > 246 kN, OK
Design of internal members
Maximum design compression force = 42 kN
Maximum design tension force = 82 kN
Maximum length in compression is = 970 mm
Try a 70 × 70 × 5 SHS, in S355 steel.
Following the same design process as above, the following resistances can be calculated:
Flexural buckling resistance (Lcr = 970mm), Nb,Rd = 419 kN
Tension resistance, Npl,Rd = 450 kN
Thus all internal members will be selected as
70 × 70 × 5 SHS, in S355 steel.
Serviceability limit state (SLS)
The deflections should be checked under un-factored variable loads and that permanent load should not be included.
Partial factors for actions
Partial factor for permanent action G = 1.0
Design value of combined actions
= 1.0 * 0.6 = 0.6 kN/m2
Design value of combined actions on truss
= 6 × 0.6 × 3.5/Cos 150 = 13.0 kN
Deflection
The maximum allowable deflection is assumed to be span/300;
Span/300 = 14000/300 = 46.67 mm.
The maximum deflection of the truss is obtained for the SLS value of combined actions (i.e. Fd = 13.4 kN). The deflection at the apex was found to 6.4 mm when all of the joints are assumed to be pinned. Deflection is therefore satisfactory.
Connections
Protecting the joint will depend on the type of joint, joint geometry and the powers subjected to the individuals members.
The obstruction of joint is checked at the design stage, so proper individuals can be guaranteed that notwithstanding the individuals opposing the design load, the joints can likewise exchange the part powers without reinforcing.
The design of hollow section joints is shrouded in BS EN 1993 - 1-8
|
Fd = 43.92 kN
FAB = –255 kN
FAC = 246 kN
FBC = –42 kN
FBD = –243 kN
FCD = 82 kN
FCE = 164 kN
NEd =255 kN
The section is at
least Class 3
Nc,Rd > NEd
NEd = 246 kN
Npl,Rd > NEd
NEd = 42 kN
|
Loading on the structure and strength calculations
It should note that loads will act on different parts of the structure almost all directions. In some cases the load will acts alone while other times simultaneously. Loads which will result into production of the highest stresses will be used for analysis of the building.
Usually those structures ought to be intended to oppose forces that may cause damage. Structures ought to be solid and hardened to withstand the stresses caused by the acting loads. It is in this way essential to know the foreseen loading conditions. Calculations of the loads following up on a structure allowable stress values for design. These qualities decide the plan of the joints, beams and columns utilized in developing the building. Structures are intended for a particular reason.
Loads on structures are ordered into two major classes. Gravity loads and parallel loads. Gravity loads pull vertically downwards because of gravity while parallel loads act in the level bearing.
Connection detail
Column Analysis
The columns mandate is to link the foundation and the roof truss, the main stresses that are projected to the column are snow load and wind load, where buckling of the column will be resulted by the snow load, whereas the wind load will result to column to act as a cantilever beam having distributed load.
Column base Joint
The column base is expected to be strong and firm in order to be able to provide rigidity that will be required during vibrations. The role of the base is to give support to the column that supports the roof truss and also the walls of the entire building. This is an indication that the base strength need to be extreme higher
In addition, the loads acting on the bolt will depend on the loads that are acting on the column. The loads will incorporate; wind load and column weight. These loads apply compression, tension and shear forces on the bolt. In some cases the forces may act together for instance tension and compression or the forces can act alone. Bearing weight on the bolt because of the plate is additionally experienced on the bolt.
The wind load acting on the side of the column creates a bending moment at the base. The bending moment of the jolt results to one portion of the bolt encountering strain and the other half compression. The point load at the highest point of the column because of the snow load and load of the column itself, results to compression at the base subsequently helping in the tying down. This thus lessens the bending moment of the bolts caused by the wind load. This prompts the conclusion that the wind load is most basic load acting on the bolts.
Bracing analysis
The bracing are predominantly intended to shield the columns and assemblies of trusses from the wind load. They are found on the sides of the building where the wind first comes into contact.
The part in the supporting absorbs a portion of the force caused by the wind load. This prevents the force being exchanged to different trusses and column members.
Truss connection analysis
The beams that connect the members together ought to be firm and sufficiently solid to oppose the load caused by the snow load. The beams are additionally used to join the roof material together with the trusses. The beams are required not to deflect or have high stresses because of their essential use.
Construction of the steel structure
Discuss the following five aspects of the construction of your structure:
Prefabrication of the steel components
The steel components that ranges from column, beams and boilts were purchased at Australia steel institute and packed on heavy loriers which were used as a means of transportation to the site store that has been temporary build within the site.
Construction sequence
The Intec warehouse steel structure construction started by first carrying ou a geotechnical reserch, which was foolowed building the foundation of the structure, the colums and rafters where then erected, and beams were punched and welded to the columns, this was followed by the girts, purlins and frame openings, later on the roofs and walls will by screwing the sheeting to the frames for walling and later roof pannel, lastly the aesthetic by adding bells and whistles.
Ease and safe erection procedures
The structure was easily erected by first starting with the colums, followed by beams, and ending up with walls and roofings.
Efficient site management
The site was easily managed by the clerk of work, who had assigned the steel expertise role and responsibility to report to him incase of any problem that may arise at each and every point of the construction work.Material handling
The materials where handled mainly using craines since they very heavy, similarly all the workers were all equipped with construction safety cloathes
Composite slab comprise of profiled steel decking with an in-situ strengthened concrete top. The decking serves as perpetual formwork to the concrete, and also gives an adequate shear bond to the concrete so that, when the concrete has achieved in its strength, the two materials act together compositely.Composite beams are typically hot rolled or manufactured steel sections that demonstration compositely with the slab. The composite collaboration is accomplished by the connection of shear connectors to the top flange of the beam. These connectorsfor the most part appear as headed studs. preceding setting the concrete. The shear connectors give adequate longitudinal shear association between the beam and the concrete with the goal that they act together structurally.
Composite slabs and bars are usually utilized with steel columns in the buildings structures due to the speed of development and general auxiliary economy that can be accomplished.
The design of the building for quality before analysis is very amazing on the grounds that the vast majority of the beams, columns, roof trusses and bracing connections can oppose the forces caused by the given loads. Distinctive loading conditions are connected on the structure to see whether the structure will in any case be steady. Nonetheless, a few beams under certain loading conditions have exceptionally high stresses and deflections. Safety values for deflections and stresses are ascertained in the analysis. In the event that the structure encounters estimations of stress and deflections that are near the safety values, at this point it need a new process redesign of the members of the structure.
References
Beeby, A.W. and Narayanan, R.S., 2005. Designers' Guide to EN 1992-1-1 and EN 1992-1-2. Eurocode 2: Design of Concrete Structures: General Rules and Rules for Buildings and Structural Fire Design. Thomas Telford.
Brettle, M.E. and Brown, D.G., 2009. Steel Building Design: Concise Eurocodes. SCI Publication P, 362, p.2009.
Bureau, A., 2006. NCCI: Elastic critical moment for lateral torsional buckling. SN003a-EN-EU, Access Steel< project. access-steel. com/Content/Content. htm>[26.11. 06].
Bureau, A., 2006. NCCI: Shear resistance of a simple end plate connection. SN014a-EN-EU, Access Steel< project. access-steel. com/Content/Content. htm>[26.11. 06].
Gardner, L. and Nethercot, D.A., 2011. Designers' Guide to Eurocode 3: Design of Steel Buildings. ICE publishing.
REAL, P., Couto, C., Lopes, N. and Rodrigues, J.P., 2010. Stability Check of Steel Frames Exposed to Fire. In Structures in Fire: Proceedings of the Sixth International Conference (p. 27). DEStech Publications, Inc.
