HomeMy WebLinkAboutFailing Rooftop SASeptember 11, 2015
Ms. Andy Pereira B+T Group
Ryka Communications, LLC 1717 S. Boulder, Suite 300
918 S. Horton St., Ste 1002 Tulsa, OK 74119
Seattle, WA 98134 (918) 587-4630
(206) 523-1941 btwo@btgrp.com
Subject: Structural Analysis
Carrier Designation: Carrier Site Number: 11566-A
Carrier Site Name: Cedar River
Ryka Communication, Designation: Site Number: SD24
Site Name: Cedar River
Engineering Firm Designation: B+T Group Project Number: 90141.002.01a
Site Data: 2439 Southeast Maple Valley Highway, Renton, WA, King County
Latitude 47.47750°, Longitude -122.18694°
Rooftop Mounted Antennas at 20’
Dear Andy Pereira,
B+T Group is pleased to submit this “Structural Analysis” to determine the structural integrity of the above
mentioned rooftop supported telecommunications site.
The purpose of the analysis is to determine acceptability of the existing rooftop and building to sufficiently
support the telecommunications equipment presented in this report. Based on our analysis we have determined
the suitability for the structure and foundation, under the following load case, to be:
Existing + Proposed Equipment Insufficient Capacity
Note: See Table 1 and Table 2 for the proposed and existing loading, respectively. Requires Modification design for
Antenna mounting frame
The analysis has been performed in accordance with the Seattle Building Code, the ASCE 7 standard, and the
2012 IBC based upon a wind speed of 110 mph 3-second gust.
All equipment proposed in this report shall be installed in accordance with the drawings for the determined
available structural capacity to be effective.
We at B+T Group appreciate the opportunity of providing our continuing professional services to you and Ryka
communications. If you have any questions or need further assistance on this or any other projects please give
us a call.
Respectfully submitted by:
B+T Engineering, Inc.
Nabin Maharjan. E.I. John W. Kelly, P.E., S.E.
Project Engineer Vice President
September 11, 2015
Structural Analysis Site No. SD24
Project Number 90141.002.01a, Cedar River Page 1
TABLE OF CONTENTS
1) INTRODUCTION
2) ANALYSIS CRITERIA
Table 1 - Proposed Antenna and Cable Information
Table 2 - Existing and Reserved Antenna and Cable Information
3) ANALYSIS PROCEDURE
Table 3 - Documents Provided
3.1) Analysis Method
3.2) Assumptions
4) ANALYSIS RESULTS
4.1) Recommendations
5) APPENDIX A
September 11, 2015
Structural Analysis Site No. SD24
Project Number 90141.002.01a, Cedar River Page 2
1) INTRODUCTION
The proposed telecommunications equipment will be located on the roof of an existing one story building. There
are existing telecommunications antennas mounted on two sector frame mounts. The proposed loading consists
of removing the existing sector frame mounts and installing all existing and proposed antennas on the new
tripod mounts. Two of the existing antennas will be removed and four proposed antennas and their associated
equipment will be installed.
2) ANALYSIS CRITERIA
The structural analysis was performed for this structure in accordance with the 2012 International Building Code
and the ASCE 7 Design Standard. The TIA-222-G apply to telecommunications towers. Although
telecommunications equipment is present, this structure is primarily a building and is more appropriately
assessed with the ASCE 7 Standard. The design wind speed for this location is 110 mph 3-second gust.
Table 1 - Proposed Antenna and Cable Information
Mounting
Level (ft)
Number
of
Antennas
Antenna
Manufacturer Antenna Model
Number
of Feed
Lines
Feed
Line
Type
Note
20
2 Commscope SBNHH-1D65C
-- -- -- 4 Alcatel Lucent RRH4x25-WCS
2 Alcatel Lucent 3JR52703AAAA
Table 2 - Existing and Reserved Antenna and Cable Information
Mounting
Level (ft)
Number
of
Antennas
Antenna
Manufacturer Antenna Model
Number
of Feed
Lines
Feed
Line
Type
Note
20
3 Kathrein 742-264
14 1 5/8” Equipment
to be
Relocated
1 Powerwave 7780
6 -- LGP 21401
2 Nokia MHA CS72993.08
2 -- 700MHz RRH 2 Fiber
2 -- DC2 SSU 4 DC
1 Kathrein 80010764_716
-- --
Equipment
to be
Removed
1 Kathrein 80010766_716
2 -- Ballasted Rooftop Mounts
3) ANALYSIS PROCEDURE
Table 3 - Documents Provided
Document Remarks Reference Source
Photos -- Date: 06/16/2015 B+T Group
Structural Inspection Report -- Date: 07/02/2015 B+T Group
Existing Loading RFDS Date: 06/23/2014 Ryka Proposed Loading
Structural Analysis By PTS LLC Date: 05/28/2009 Ryka
CD’s By Morrison Hershfield Date: 07/13/2011 Ryka
September 11, 2015
Structural Analysis Site No. SD24
Project Number 90141.002.01a, Cedar River Page 3
3.1) Analysis Method
This building currently supports telecommunications equipment. Two antennas will be removed and
(4) new antennas will be added. Calculations were run on multiple mounting options with all returning
the same result. The existing rooftop is insufficient for this proposed loading. A site inspection
revealed the rooftop construction to be different than what was previously reported. Even without any
additional loading from telecommunications equipment, the roof structure does not meet code
requirements.
3.2) Assumptions
1) The structure was built in accordance with the designer’s specifications.
2) The configuration of antennas, transmission cables, mounts and other appurtenances are as
specified in Tables 1 and 2 and the referenced drawings.
3) Existing loading was assumed based on final proposed loading.
This analysis may be affected if any assumptions are not valid or have been made in error. B+T
Group should be notified to determine the effect on the structural integrity of the structure.
4) ANALYSIS RESULTS
4.1) Recommendations
1) The support system for the telecommunications equipment is structurally insufficient at this site.
2) All existing telecommunications equipment should be removed from the existing structure.
3) It is our recommendation that a new wood laminate pole be installed for the mounting of the
proposed loading.
September 11, 2015
Structural Analysis Site No. SD24
Project Number 90141.002.01a, Cedar River Page 4
APPENDIX A
ADDITIONAL CALCULATIONS
B&T Engineering, Inc.
NM
90141.002.01a
Cedar River SD24
SK - 1
Sept 11, 2015 at 9:30 AM
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B&T Engineering, Inc.
NM
90141.002.01a
Cedar River SD24
SK - 2
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B&T Engineering, Inc.
NM
90141.002.01a
Cedar River SD24
SK - 3
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Code Check
No Calc > 1.0.90-1.0.75-.90.50-.75 0.-.50
Maps
47.4775, -122.18694
SD24 Cedar River
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