TOWERKRAFT ENGINEERING, P.C.DESIGN AND ANALYSIS OF COMMUNICATION STRUCTURES

ENGINEERING EVALUATION165' 175' Sabre S3TL-29

Tower Site:Oswego City (OSW), NY

Oswego County

Prepared For:Oswego County

46 East Bridge Street, 3rd FloorOswego, NY 13126

Prepared By:Steven Fehlhafer, P.E.Towerkraft Engineering

August 4, 2010

Project No. 7396

216 EAST 3rd STREET • ALLIANCE, NE 69301 • PHONE (308) 762-5002 • FAX (308) 762-1489

SCOPE

As requested by Oswego County, Towerkraft Engineering has performeda structural stress analysis on the existing 165' Sabre Model S3TL-29 self supporting tower located at Oswego City, NY. It isproposed to add an additional 10' to the tower for a final heightof 175'. The analysis was performed per ANSI design standard TIA-222-G (Telecommunications Industry Association Structural Standardfor Antenna Supporting Structures and Antennas)). The followingfactors and structure class were used in the analysis:

• Exposure Category C: “Open terrain with scatteredobstructions having heights generally less than 30ft. Thiscategory includes flat, open country, grasslands andshorelines in hurricane prone regions.” (ANSI/TIA-222-G,section 2.6.5.1, page 12). Exposure Category C is thedefault category per TIA.

• Topographic Category 1: “No abrupt changes in generaltopography, e.g. flat or rolling terrain...”(ANSI/TIA-222-G, section 2.6.6.2, page 13).

• Structure Class II: “Structures that due to height, use orlocation represent a substantial hazard to human lifeand/or damage to property in the event of failure and/orused for services that may be provided by other means” (ANSI/TIA-222-G, Table 2-1, page 39).

The purpose of this analysis is to determine the structuralcapacity of the tower to withstand the loading of the antennaslisted below.

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ANTENNAS

Elev Item Feedline Remarks

175' 22" x 10" x 1.5" Panel 3/8 Existing

168' (3) RFI TXRX FSA-10-67 (3) 1 1/4 Proposed

166' (2) 6' side arms na Proposed163' (3) DB876G45A-XY (Sector A) (3) 1 5/8 Existing

163' (1) EMS RR651802DPL2 (Sector A) (2) 1 5/8 Existing

163' (3) DB846H65E-SX (Sector B) (3) 1 5/8 Existing

163' (1) EMS RR651802DPL2 (Sector B) (2) 1 5/8 Existing

163' (3) DB846H65E-SX (Sector C) (3) 1 5/8 Existing

163' (1) EMS RR651802DPL2 (Sector C) (2) 1 5/8 Existing

163' (3) Sector Mounts na Existing

150' (2) EMS FV651408DBL2 (Sector A) (2) 1 5/8 Existing

150' (2) EMS AV651802DPL2 (Sector A) (2) 1 5/8 Existing

150' (2) EMS FV651408DBL2 (Sector B) (2) 1 5/8 Existing

150' (2) EMS AV651802DPL2 (Sector B) (2) 1 5/8 Existing

150' (2) EMS FV651408DBL2 (Sector C) (2) 1 5/8 Existing

150' (2) EMS AV651802DPL2 (Sector C) (2) 1 5/8 Existing

150' (3) Sector Mounts na Existing

132' TX-RX 101-68-10-03N & 6' s.a. 1 1/4 Proposed

124' Andrew PAR6-59 w/radome EWP-52-59 Proposed

110' Andrew 800mm Valuline w/shroud EWP-90 Proposed

The analysis has been performed with the following load cases:

a. 90 mph wind at the face of the tower (no ice).b. 90 mph wind at the apex of the tower (no ice).c. 90 mph wind parallel to one tower face (no ice).d. 40 mph wind at the face of the tower (1" ice).e. 40 mph wind at the apex of the tower (1" ice).f. 40 mph wind parallel to one tower face (1" ice).

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RESULTS:

MAXIMUM MEMBER USAGE

Elevation LegPercent Usage

BracingPercent Usage

175'-165' 2% 6%

165'-160' 5% 10%

160'-140' 60% 49%

140'-120' 91% 75%

120'-100' 95% 51%

100'-80' 84% 78%

80'-60' 85% 95%

60'-40' 82% 69%

40'-20' 96% 96%

20'-0' 80% 90%

The maximum percent usage allowed by TIA-222-G is 100%. The towermembers meet the requirements of TIA.

FOUNDATIONS

The original design drawing shows the base and anchor foundationsizes and the original design reaction forces. Per TIA-222-G, a1.35 factor may be applied to the original design reactions forcomparison to the new reaction forces. Based on the comparison,the foundation is considered to be adequate for the addition of theproposed antenna loads and 10' tower section.

Load Type ForceDirection

OriginalReactionsx 1.35

TIA-222-G Reactions

TotalO.T.M. =Shear =Axial =

3829 k-ft38.1 kips124.5 kips

3527 k-ft (o.k.)36.6 kips (o.k.)118.0 kips (o.k.)

IndividualAxial =Uplift =Shear =

290.5 kips225.6 kips25.1 kips

247.9 kips (o.k.)223.8 kips (o.k.)22.7 kips (o.k.)

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COMMENTS

It is recommended that Sabre be contacted for the 10' tower sectionat elevation 165'-175'. The member sizes shown on Towerkraftdrawing number 7396-DS may be used for the new tower section.

If the antenna loading changes in the future, it is recommendedthat the tower be re-analyzed to ensure compliance with TIA-222-G.

If any item on the existing tower varies from what is stated inthis report or on the drawings, the certification by TowerkraftEngineering shall be considered invalid and Towerkraft Engineeringshall be notified immediately for revised analysis.

CONCLUSION

The existing tower will meet TIA-222-G with addition of theproposed antenna loads and 10' tower section at elevation 165'-175'.

This report is based on the following:

a. ANSI/TIA-222-G. b. Antenna loading and tower information supplied by Oswego

County.c. All leg steel analyzed as 50 ksi yield strength. All other

steel analyzed as 36 ksi yield strength.d. Antenna dimensions per manufacturer’s specifications (when

possible).e. Structural analysis and engineering by Towerkraft

Engineering.

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