STRUCTURAL INTEGRITY SURVEY SITE: 163323 Worthing Swandean AMC & TRS 1.75m Stub Tower
Date of Inspection Operator Site ID Site Address
NGR Structure type and height
Date: 21 November 2014 Rev. A
23rd October 2014 163323 SALVINGTON ROAD, DURRINGTON, WORTHING, BN13 2JJ TQ 12320 05230 1.75m Stub Tower
RAG Status Structure Loading Structure Condition
Green
Grillage
Green
Compound/Demise
Green
Health and Safety Headframe Connection
Green Green Amber
Green
Structural Report - 163323 Worthing Swadean AMC & TRS
DOCUMENT ISSUE RECORD Distribution Copy No. 1
Issued to
Holder’s Name
Project Role
ARQIVA, Structures
D. Pendaeli
Regional Engineer
2 3 4 5 6 7 8
Revision History Rev
Written By
Date Written
Doc. Status
Approved By
A
WM
20/11/2014
ISSUED
AST
Signed
Issue Date
21/11/2014
B C D E
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page ii
Contents 1.0
INTRODUCTION 1.1 Structures to be assessed
2.0
INSPECTION SUMMARY 2.1 General Notes 2.2 Condition of structure 2.2.1 Tower steelwork 2.2.2 Connection to roof 2.2.3 Protective paint system and galvanising 2.2.4 Ancillaries
3.0
STRUCTURAL APPRAISAL 3.1 Sources of data and basis of applied loading 3.2 Analysis approach 3.3 Capacities of structural members 3.4 Tower Design Appraisal Summary Sheet 3.5 Equipment Schedule
APPENDIX A
REFERENCES
APPENDIX B
PHOTOGRAPHS
APPENDIX C
TOWER SCHEMATIC
APPENDIX D
MS TOWER/ANALYSIS EXTRACT
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page iii
1.0
INTRODUCTION
1.1
2.0
Structures to be assessed This report will cover the appraisal of the stub tower at 163323 Worthing Swandean AMC & TRS. INSPECTION SUMMARY
2.1
General Notes The Tower is located on the roof of a BT exchange. The base of the tower is approximately 18m above sea level. All antenna heights are taken to the mean heights of the antennas. Bearings are estimated on survey.
2.2
Condition of structure
2.2.1
Tower steelwork A close visual inspection was carried out of the tower se ctions and bolts. The overall condition of the structure is very good. The bolts are all in very good condition and evenly tightened.
2.2.2
Connection to roof/grillage The grillage is in good condition, with the bolts evenly tightened. Photo showing bolt connecting (see Appendix B, Page iii), the stub tower leg to the g rillage steel frame, has an edge distance less than required by British Standards or Eurocode. The bolt is primarily in tension and shear is minimal, therefore this is likely to be adequate.
2.2.3
Protective paint system and galvanising The galvanising has no significant signs of discolouration and is in very good condition throughout the height of the tower, and grillage.
2.2.4
Ancillaries The antennas are all in good condition.
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page 1
3.0
STRUCTURAL APPRAISAL
3.1
Sources of data and basis of applied loading The tower and grillage were surveyed to their full height. The data from the survey always then used to model the structure. The applied loading was calculated from the antennas noted at the time of the survey.
3.2
Analysis approach i) Wind speeds The wind speeds have been calculated using BS8100-1:1986: Lattice towers and masts – Part1: Code of practice for loading.
3.3
ii)
Equipment loading Equipment loading has been derived from measurements and records taken on site and from manufacturer’s technical documentation. For substantial head frame installations, an approach has been adopted for assessing the wind loading that accounts for mutual shielding of equipment where appropriate.
iii)
Classification of quality The Tower is well engineered and can be assumed to have been designed, fabricated and built to a good quality system. The Tower is in a good maintenance condition and there is a regular maintenance inspection regime. For these reasons, the quality class has been taken as B for this structure.
iv)
Partial safety factor on wind speed The factors for wind and dead loads have been taken from BS8100 Figure 2.1 – Partial safety factors on wind speed, ice thickness, dead load and design strength. This is commensurate with the typical classification for broadcast structures, and with the sites location in urban location.
v)
Grillage The grillage has been assessed with partial factors matching the tower.
vi)
Design life For this assessment the full 3 second gust windspeed has been used, this gives a return period of 50 years.
Capacities of structural members The capacity of the section is assessed within the MSTower analysis output file using BS81003:1999: Lattice towers and masts – Part 3: Code of practice for strength assessment of members of lattice towers and masts.
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page 2
3.4
Tower Design Appraisal Summary Sheet DESIGN APPRAISAL SUMMARY
Client: ARQIVA
Completed By: Jason Vargas
Project: Structural Integrity Surveys
Site ID : 163323
Location of Structure(s)
Worthing Swandean AMC & TRS, Salvaton Road, Durrington
Type of Structure(s)
1.75m Stub Tower
Grid Ref
TQ 12320 05230
Design Service
Structural Appraisal
Structure Description
The structure is a 1.75m Lattice Rooftop Tower on top of a steel grillage frame interface. The tower is triangular in cross section and has a c onstant face width of 0.75m. Legs are CHS sections while bracings are RSA sections. Steel grillage is made up of UB and UC sections and supported on 8 locations on to t he roof structure of the building. Steel is assumed grade S275 and bolts are assumed grade 8.8. Design Codes/Standards BS8100-1:1986 BS8100-3:1999 BS5950-1:2000 Geotechnical Info Not Applicable
Reference Documents
Design Life
25 Years
Environmental Loading
Wind Loading
Ice/Snow loading Imposed Loading
Antennas Feeders Others
Date:
07/11/2014
Checked By: James Brennan
Vb = 20.5m/s with reference to BS EN 1991-1-4:2005 Alt=18m AMSL Terrain Category = 1 , !v = 1.20, !m = 1.1 ro = 52mm r w = 2mm
Ice Loading Non Critical
See Equipment Schedule See Equipment Schedule None
Deflection Criteria
Return Period 1 in 5 years
Fixed Access System
Internal Ladder
Sub-soil Conditions
Not Applicable
Foundation Design Criteria
Not Applicable – Tower supported on steel grillage
Special Considerations
None
APPRAISAL RESULTS Existing configuration: Maximum usage factors:
Maximum deflection exclusive of Grillage: Grillage Maximum Reactions (Factored):
Leg
=
0.14
Bracings
=
0.37
Grillage Beams
=
0.14
At Highest Ancillary
=
0.03
Maximum Downthrust
=
14.97 kN
Maximum Uplift
=
5.3 kN
Maximum Shear
=
5.4 kN
CONCLUSIONS & RECOMMENDATIONS The steel tower and its steel grillage is structurally adequate for the existing loading. There are no available information on the existing holding d ownbolt system (i.e, hdb embedment depth, concrete details, etc) therefore we cannot comment on its adequacy. Maximum factored loadings are indicated as above. Analysis on the supporting b uilding is not included in the investigation.
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page 3
S 4 R e T g & a P C M A n a e d a w S g n i h t r o W 3 2 3 3 6 1 t r o p e R l a r u t c u r t S
s t n e m m o C
r e e d p e y e t F
e l u d e h c S t n e m p i u q E 5 . 3
g n i r a e B
° ° ° 0 0 0 2 1
r o t a r e p O
2 2 2 2 2 2 O O O O O O
e p y T
a n n e t n A r o t c e S B J
a n n e t n A r o t c e S l a c e R
a n n e t n A r o t c e S B J
a n n e t n A r o t c e S l a c e R
a n n e t n A r o t c e S B J
a n n e t n A r o t c e S l a c e R
n o i t a c o L
b u t S
b u t S
b u t S
b u t S
b u t S
b u t S
) m ( t h g i e H
. f e R
° 0 2 1
° 0 4 2
° 0 4 2
5 . 5 . 5 . 5 . 5 . 5 . 2 2 2 2 2 2
4 1 0 2 r e b m e v o N 1 2 : A . e v t a e D R
APPENDIX A
REFERENCES
British Standards 1
BS8100-1:1986: Lattice towers and masts Part1: Code of practice for loading.
2
BS8100-3:1999: Lattice towers and masts Part 3: Code of practice for strength assessment of me mbers of lattice towers and masts.
3
BS5950-1:2000: Structural use of steelwork in building Part 1: Code of practice for design – Rolled and welded sections
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page Bi
APPENDIX B
Date: 21 November 2014 Rev. A
PHOTOGRAPHS
Structural Report - 163323 Worthing Swadean AMC & TRS Page Bii
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page Biii
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page Biv
APPENDIX C
TOWER SCHEMATIC
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page Bv
Date: 21 November 2014 Rev. A
Structural Report - 163323 Worthing Swadean AMC & TRS Page Bvi
APPENDIX D
MS TOWER UTISATION RATIO & LUSAS ANALYSIS EXTRACTS
0.09 0.09 0.09 0.09 0.09 0.29 0.31 0.29 0.09 0.16 0.18 0.17 0.14 0.14 0.34 0.37 0.34 0.14
Enveloping on: All Scale: 1: 65.8525
Envelope 1 (Min)
Zoom: 112.0
Entity: Force/Moment - Thick 3D Beam THY THZ THZ THY Component: My THY THZ Linear/dynamic analysis THY THZ THY THZ Enveloping on: All -21.26 THY THZ THY THZ THY THZ THY THZ Envelope 1 (Min) -18.8978 THY THZ THY THZ THY THYTHZ THZ THY THY THZ -16.5356 Contour entity: Force/Moment - Thick THY THZ THY THZ3D Beam THY THZ -14.1733 Contour component: My -11.8111 Number of contours: 9 THY THY THZ THZ THY THZ THZ -9.44889 THY Contour interval: 2.36222 -7.08667 Contour maximum -1.77591E-18 at node 295 of element 155 -4.72444 Contour minimum -21.26 at node 54 of element 30 -2.36222 THY THZ Eye: (-0.60117, -0.655798, 0.456644)
Maximum -1.77591E-18 at node 295 of eleme THY THZ
Date: 21 November 2014 Rev. A
Minimum -21.26 at node 54 of element 30
Structural Report - 163323 Worthing Swadean AMC & TRS Page Bvii
