HomeMy WebLinkAbout34 Development Permit 324 Shenandoah Ph III.. • McCLURE ENGINEERING, INC.---~----
~~\~\0: January 2, 1996
Mrs. Veronica Morgan, P.E.
Assistant City Engineer
CITY OF COLLEGE STATION
P .O. Box 9960
College Station , Texas 77842
RE: DRAINAGE REPORT ADDENDUM FOR SHENANDOAH , PHASE THREE
Dear Veronica:
This letter is intended to document our response to your concerns about the ability of the
existing storm drain system in Dove Trail to accommodate the SHENANDOAH , PHASE
THREE development. You correctly noted that our submittal includes detailed information and
calculations about the ultimate conditions, but failed to specifically address the interim period of
time between the construction of Shenandoah , Phase Three and Shenandoah, Phase Four.
The following is an analysis of the existing drainage area upstream of the Dove
Trail/Barron Road intersection. Projections and estimates for the drainage area and storm drain
system were documented in the SPRINGBROOK-OAKGROVE Subdivision drainage report dated
June 28 , 1994.
A. EXISTING CONDITIONS AT OUTFALL
1. A 30" RCP storm drain @ 1.49% grade was built along Dove Trail. (The pipe was
extended across Barron Road at 4 .82 % grade ; however , for the purposes of this
analysis , the lesser slope was used to determine the system's capacity at Barron Road.)
2 . The calculated pipe capacity is 46.5 cfs (flowing full).
B. RUNOFF COMPUTATIONS FOR CONTRIBUTING DRAINAGE AREA USING
RATIONAL FORMULA
1. Time of Concentration:
Hydraulic Length = 1125'
325 L.F. Wooded & Trash Fallow Flow@ 1.5% grade , V = 0.6 fps
800 L.F. Grassed Waterway Flow@ 1.9% grade , V = 2.1 fps
Tc = 325 + 800 = 15.4 min.
0 .6(60) 2.1(60)
1722 Broadmoor, Suite 210 • Bryan , Texas 77802 • (409) 776-6700 • FAX (409) 776-6699
.,, .
'
SHENANDOAH , PHASE THREE DRAINAGE
1/2/96
2 . Runoff Coefficient:
Total Drainage Area = 15 .4 Acres
with 0.9 Acres Medium Residential
& 14.5 Acres Fallow & Wooded
c(composite) = 0.9(0.6) + 14.5(0.4) = 0 .41
15.4
3. Rainfall Intensity:
I10 = 80 = 7.10 in./hr.
(tc + 8.5)" 763
4 . Peak Dischar~e:
Q10 = 0.41(7.10)(15.4) = 44.8 cfs <46.5 cfs allowed
C . CONCLUSION:
PAGE2
Since the projected peak discharge for the drainage area is less than the capacity of the
existing storm drainage system at Barron Road/Dove Trail, the design is in compliance with
the City Drainage Ordinance. For storms greater than the 10-year storm event, the overflow
will be contained in the Dove Trail right-of-way and will enter the South Fork of Lick
Creek through the drainage corridor provided at the Cardinal Street/Dove Trail intersection
(see Springbrook -Oakgrove Plat).
Should you have any questions or need additional information , please do not hesitate to call .
. e,,/ .
Very~truly yours,
J(} I/~
~chael R. McClure, P.E., R.P.L.S.
MRM/mlm
a :\shen3drg.adn
Hugh G. Glenn, Fronds Mahoney
And Ernest D. I Leno Rivers
58. 79 Acres
vo1um~of8tl;,it~r 119
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~ ~ 8 33
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6 JI
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4 3 2
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Richland Court South
6
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14 13 12
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30" RCP-.
10
16
Spring. rook ~ Ookfl
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32 33
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BLOCK FOUR
33 32
Richland Court North
~ JS 11
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Interim Drainage Area Map
Shenandoah Phase Ill &-IV
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• McCLURE ENGINEERING, INC. ______ _
September 13, 1995
Mrs . Veronica Morgan , P.E.
Assistant City Engineer
CITY OF COLLEGE STATION
P.O . Box 9960
College Station , Texas 77842
Re: Drainage Report Addendum for Shenandoah Phase Ill
Dear Veron ica :
The Shenandoah Phase Two Final Drainage Analysis dated March 15 , 1995
(amended May 11 , 1995) states in the introduction , "The study includes the drainage
analysis for the storm water detention requirements of both Phases Two and Three of the
Shenandoah development". Minor changes in the design of Phase Three require that the
Phase Two Analysis be updated to account for these changes . The attached Exhibit "A"
(Master Drainage Map) and Exhibit "B" (Drainage Computations) may be inserted into the
Phase Two Analysis as an Addendum .
Note that calculations for all Areas of Phases Two through Five are included . The
information shown for Phase Four and Five is preliminary . No final Analysis of the
detention area included in Phase Four is offered . Because the Phase Four detention area
is not built or required with this Phase , we have not completed our design . With the
submission of Phase Four, we will submit a complete drainage report covering all Phases .
Should you have any questions concerning this revision to the Drainage Report,
please advise .
Very_ t~uly J'Jls ,
Jr)~~
Michael R. McClure, P.E., RP.LS .
MRM/mlm
attachments
1722 Broadmoor, Suite 210 • Bryan , Texas 77802 • (409) 776-6700 • FAX (409) 776-6699
DATE:
TO:
ATTN:
12/21 /95
McCLURE ENGINEERING, INC.
1722 Broadmoor, Suite 210
Bryan, Texas 77802
(409) 776-6700
FAX 776-6699
TRANSMITTAL LETTER
Mrs. Veronica Morgan, P.E.
Assistant City Engineer
CITY OF COLLEGE STATION
ATTACHED PLEASE FIND:
Six (6) additional sets of revised construction plans for SHENANIX>AH,
PHASE THREE. Three (3) additional sets for the City (total of 4) and
three (3) sets to be stamped with "approval" and returned to our office
for the Contractor's use.
THESE ARE TRANSMITTED TO YOU FOR THE FOLLOWING REASON:
For Approval Your Use Revisions Made
xx As Requested For Review and Comment
Returned after Loan to Us
RECEIVED BY:
DATE:
SIGNED BY: /Y/.f!lf'~
MICHAEL R. McCLURE, P.E., R.P.L.S.
DATE:
TO:
ATTN:
12/8/95
McCLURE ENGINEERING, INC.
1722 Broadmoor, Suite 210
Bryan, Texas 77802
(409) 776-6700
FAX 776-6699
TRANSMITTAL LETTER
Mrs. Veronica Morgan, P.E.
Assistant City Engineer
COLLEGE STATION, 'IEXAS
ATTACHED PLEASE FIND:
1. Redlined construction plans for SHENANOOAH, PHASE THREE
2. One set of revised construction plans to be checked for compliance with
redlined sets
3. Two (2) copies of Construction Cost Estimate
THESE ARE TRANSMITTED TO YOU FOR THE FOLLOWING REASON:
For Approval Your Use Revisions Made
As Requested For Review and Comment
Returned after Loan to Us
.~r
\~
RECEIVED BY:
DATE:
SIGNED BY:
MICHAEL R. McCLURE, P.E., R.P.L.S.
to Fn~ cDW
ENGINEER'S CONSTRUCTION COST ESTIMATE -tt ?z4)
SHENANDOAH,PHASETHREE
DECEMBER 7, 1995 (REVISED)
ITEM DESCRIPTION UNIT QUANTITY UNIT AMOUNT
NO. COST
STREET CONSTRUCTION
1 Erosion & Sedimentation Control LS. $2,000.00 $2,000.00
2 Clearing & Grubbing LS. 1 2,500.00 2,500.00
3 Excavation C.Y. 10,981 2.50 27,452.50
4 Cellulose Fiber Mulch Seeding S.Y. 2,225 0.50 1,112.50
5 6" Lime Stab. Subgrade (53 Lime) S.Y. 8,111 2.40 19,466.40
6 Extra Lime Ton 55 80.00 4,400.00
7 6" Flexible Base Crushed Stone S.Y. 6,433 5.35 34,416.55
8 11h" Hot Mix Asphaltic Concrete (Type DJ S.Y. 6,433 3.75 24, 123.75
9 Reinforced Concrete Curb & Gutter LF. 2,674 7.00 18,718.00
10 Reinf. Concrete Sidewalk S.F. 7,055 2.15 15,168.25
11 Reinf. Concrete Aprons S.F. 1,934 3.75 7,252.50
12 Driveway Approaches S.F. 13,664 3 .15 43,041.60
STREET CONSTRUCTION SUBTOTAL $156,610.45
DRAINAGE CONSTRUCTION
13 15" RCP (C76, Cl. Ill) LF. 58 22.00 $1,276.00
14 18" RCP (C76, Cl. Ill) LF. 130 27.00 3,510.00
15 24" RCP (C76, Cl. Ill) LF. 58 32.00 1,856.00
16 27' RCP (C76, Cl. 111) LF . 130 35.00 4,550.00
17 Concrete Junction Box Ea. 1 1,200.00 1,200.00
18 5' Recessed Cone. Inlet Ea. 2 1,750.00 3,500.00
19 1 O' Recessed Cone. Inlet Ea. 2 2,050.00 4,100.00
20 Connect to Existing Storm Drain LS. 1 250.00 250.00
21 Dry Riprap Channel Lining S.Y. 35 60.00 2,100.00
22 Trench Safety (Storm Drain) LF. 188 1.50 282.00
DRAINAGE CONSTRUCTION SUBTOTAL $22,624.00
SEWER LINE CONSTRUCTION
23 6" PVC (SDR-26, D3034)(6' to 8' depth) LF . 323 15.00 4,845.00
24 6" PVC (SDR-26 , D3034)(8' to 10' depth) LF. 1,684 16.50 27,786.00
25 6" PVC (SDR -26, D3034)(10' to 12' depth) LF. 121 18.50 2,238.50
26 Standard Sewer Manhole {< 8' depth) Ea. 4 1,200.00 4,800.00
27 Standard Sewer Manhole (8' to 1 O' depth) Ea. 5 1,350.00 6.750.00
28 Remove Plug & Connect to Existing 6" Line LS . 200.00 200.00
Page 1
ENGINEER'S CONSTRUCTION COST ESTIMATE
SHENANDOAH,PHASETHREE
DECEMBER 7, 1995 (REVISED)
ITEM DESCRIPTION UNIT QUANTITY UNIT AMOUNT
NO. COST
29 Trench Safety (Sewer System) L.F. 2.128 1.50 3,192.00
30 4" Service Line (Type 1)(17.4' Avg.) Ea . 20 650.00 13,000.00
31 4" Service Line (Type 11)(56.2' Avg.) Ea. 5 810.00 4,050.00
SEWER LINE CONSTRUCTION SUBTOTAL $66.861.50
WATER LINE CONSTRUCTION
32 6" PVC (C900, Cl. 200) L.F. 1.521 14.50 $22,054.50
33 8" PVC (C900, Cl. 200) L.F. 665 17.50 11,637.50
34 Rre Hydrant Assembly (Type I) Ea. 2 1,600.00 3,200.00
35 Connect to Existing 6" A.C. Line LS. 300.00 300.00
36 Connect to Existing 8" A.C. Line LS . 1 350.00 350.00
37 6" M.J. Gate Valve Ea. 4 350.00 1,400.00
38 8" M.J. Gate Valve Ea. 2 500.00 1,000.00
39 'Z' Blow-off Assembly with 6" C9p Ea. 400.00 400.00
40 2" Blow-off Assembly with 8" Cap Ea. 410.00 410.00
41 8" X 6" M. J. Cross Ea. 240.00 240.00
42 6" X 6" M.J. Hydrant Tee Ea. 230.00 230.00
43 8" X 6" M.J. Hydrant Tee Ea. 240.00 240.00
44 6" X 45° M.J. Bend Ea. 4 175.00 700.00
45 6" X 13" Anchor Coupling Ea. 3 180.00 540.00
46 8" X 13" Anchor Coupling Ea. 2 210.00 420.00
47 11h" Copper Service (49' Avg. Length) Ea . 12 715.00 8.580.00
48 1" Copper Service (44' Avg. Length) Ea. 1 530.00 530.00
49 Trench Safety (Water Line) L.F. 2,046 1.50 3.069.00
WATER LINE CONSTRUCTION SUBTOTAL $55,301.00
TOTAL ESTIMATED COST OF CONSTRUCTION $301.396.95
Page2
DEVELOPMENT PERMIT
PERMIT NO . 324
Shenandoah Phase 3
FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA
RE: CHAPTER 13 OF THE COLLEGE STATION CITY CODE
SITE LEGAL DESCRIPTION:
Shenandoah Subdivision, Phase 3
SITE ADDRESS:
n/a
OWNER:
Edward Froehling
3887 High Lonesome
College Station, Texas 77845
DRAINAGE BASIN:
South Fork of Lick Creek, Basin IV
TYPE OF DEVELOPMENT:
This permit is valid for site construction according to approved plans . Contractor shall
prevent silt and debris from leaving the site in accordance with the City of College Station
Drainage Policy and Design Criteria. Owner and/or contractor shall be responsible for any
damage to existing city streets or infrastructure due to heavy machinery and/or equipment.
In accordance with Chapter 13 of the Code of Ordinances of the City of College
Station, measures shall be taken to insure that debris from construction, erosion, and
sedimentation shall not be deposited in city streets, or existing drainage facilities .
I hereby grant this permit for development of an area outside the special flood
hazard area . All development shall be in accordance with the plans and specifications
submitted to and approved by the City Engineer in the development permit application for
the above named project and all of the codes and ordinances of the City of College Station
that apply .
<;)~~
Administrator/Representative Date 1
Date
Contractor Date
Figure XII
Application Form
Development Permit
Inside/Outside Established Flood Hazard Areas
City of CoUege Station, Texas
(re: Ordinance No. 1728)
Site Legal Description: _ __:S=:HENANOO.=:::.::=..:~Aff=,~P..:;HAS~;:;:;E_THREE::.:=-==:__------------------
Site Address: end of Hunter Creek Drive in SHENANOOAH, PHASE ONE
Owner: EDWARD FROEHLING Address: 3387 High Lonesome, c.s. 77845
~--~-----------~---~~-~ Telephone No.: __!..7.L76~8,!_f,2~6.J.L6 _____ _
~ Michael R. McClure, P.E., R.P.L.S. Address: 1722 Broadrnoor, Bryan. 77802
Engineer: --'M""'"cCL"-==URE==........,EN ... G .... I=N--EER __ IN_G~, _IN_C_,. ________ Telephone No.: .....1.7~7~6=.i.6"'"'701.1..10~-------
Contractor: CENTRAL TEXAS SITEWORKS, INC. Address: P.O. Box 2338, Bryan, 77806
Telephone No.: ..... aL.:14..1.1.6~-J...J1 8o.l.JO.L.3,,__ _____ _
Date Application Filed:---------------Approved:------------
Application is hereby made for the following specific waterway alterations: subdivis ion develognent
on land that drains to the South Fork of Lick Creek
Attach ed as part of this application:
63 Application Fee
IBI Signe d Certificate
O Site and Construct ion Plans, with supporting document<1tion : iwo (2) copies of each
O Oth<:;r:
~~-~~---~~~--~~-~~
ACKNOWLEDGEMENTS:
I, EDWARD FROEHLING as owner, hereby acknowledge or a ffirm that:
The above Drainage Plan and supporHng documents complies wiht the require ments of Ordinance No. 1728,
:~11~
Own e r ·
)
I I Date
Date
o ~ue
Page 1of2
I
#!*"/
/
/
..
Figure XII Continued
CERTIFICATIONS:
A I, certify that any nonresidential structure on or
proposed to be on this site as part of this application meets flood-proofing requirements as
set out in Section of Ordinance No. 1728
Architect/Engineer Date
B. I, certify that the finished floor level of the lowest
floor, including any basement, of any residential structure as part of this application is or
proposed to be at or above the base flood elevation as established in the latest Federal
Insurance Administration flood hazard study and maps, as amended.
Architect/Engineer Date
Architect/Engineer Date·
REVIEWED FOR APPROVAL: -----=-----------Floodplain Administrator Date
APPROVAL: Special conditions or comments as part of approval: __________ _
ACCOUNT NO . ________________ _
377968
O-r1 ,:__j . ,. q ,)'-
THANK YOU~
Barry R. McBee , Chairman .
R. B. "Ralph" Marquez, Commissioner
John M. Baker, Commissioner
Dan Pearson, Executive Director
TEXAS NATURAL RESOURCE CONSERVATION COMMISSION
Protecting Texas by Reducing and Preventing Pollution
Michael R. McClure, P.E., RPLS
McClure Engineering , Inc.
1722 Broadmoor, Suite 210
Bryan, Texas 77802
Re: City of College Station
Shenandoah, Phase Three
TNRCC Permit No.: Unknown
WPR Log No.: 016/032
County: Brazos
Dear Mr. McClure:
January 16, 1996
We have received the design submittal included with your cover letter dated 1/02/1996.
The rules which regulate the design, installation and testing of domestic wastewater projects are found
in 30 TAC, Chapter 317, of the TNRCC's rules titled, Design Criteria for Sewerage Systems. All
plans and specifications submitted for TNRCC approval must comply with these rules.
Beginning on September 1, 1994, severe budget reductions required the TNRCC to eliminate most
reviews of domestic wastewater project plans and specifications. At most, only a cursory review of
the proposed project was performed. A technical review to determine conformity with 30 TAC
Chapter 317 has not been performed. The proposed project is approved with the following comments
and conditions:
1. An engineering report must be prepared and sealed by a Professional Engineer registered in
the State of Texas. This engineering report must include all constants, graphs, equations, and
calculations, which are needed to both justify the design and show full compliance with Section
317 .1 ( c) of the TNRCC 's rules requiring a final engineering report. Copies of this report shall
be made available to the TNRCC, upon request.
2. The final version ~i.the project plans and specifications shall include any and all information
necessary to show full compliance with the applicable requirements detailed in Chapter 317 of
the TNRCC's rules. Copies of the final version of the project plans and specifications shall
be made available to the TNRCC, upon request.
P.O. Box 13087 Austin , Texas 78711-3 087 • 512/239 -1000
printed on recycl tJ pil pu u1init M>y-b.u.ed ink
Michael R. McClure , P .E ., RPLS
Page 2
3 . Any test results necessary to show compliance with the testing requirements of Chapter 317
shall be made available to the TNRCC , upon request.
4 . The TNRCC still maintains its review authority and may utilize this authority at any time in
the future . If plans are to undergo review , the TNRCC will notify you upon our receipt of the
project . Also , please be aware of Section 317 . l(a)(2)(A) of the rules which states, "Approval
given by the commission is not intended to relieve the sewerage system owner or the design
engineer of any liabilities or responsibilities with respect to the design , construction , or
operation of the project ."
5 . Within 60 days of the completion of construction, an appointed engineer must notify both the
Permitting Section of the TNRCC 's Wate r shed Management Division and the app ro priate
Region Office of the date of completion . The engineer must also provide written certification
that all construction, materials and equipment, and test results were substantially in accordance
with the approved plans and specifications, the rules of the TNRCC and any change orders
filed with the TNRCC. All notifications, certifications and change orders must include the
signed and dated seal of a Professional Engineer registered in the State of Te xas .
6. All plans and specifications shall conform with any other waste discharge requirements and
water quality standards established by the TNRCC, as the requirements pertain to a regulated
discharge.
If you have any questions or if we can be of any further service , please call me at (512) 239-4554.
Sincrely,
Louis C. Herrin, III , P.E.
Plan Review Team
Wastewater Permits Section
cc : City of College Station
TNRCC, Region 9 -Office
DATE:
TO:
ATTN:
1 /3/96
McCLURE ENGINEERING, INC.
1722 Broadmoor, Suite 210
Bryan, Texas 77802
(409) 776-6700
FAX 776-6699
TRANSMI'rl'AL LETTER
Mrs. Veronica Morgan, P.E.
Assistant City Engineer
CITY OF COLLEGE STATION
ATTACHED PLEASE FIND:
Copy of Engineering Sewerage Report on SHENANDOAH, PHASE THREE that
was sent to TNRCC (attachments listed but not enclosed in your copy).
THESE ARE TRANSMITTED TO YOU FOR THE FOLLOWING REASON:
For Approval xx Your Use Revisions Made
As Requested For Review and Comment
, Returned after Loan to Us
RECEIVED BY:
DATE:
SIGNED BY:
MICHAEL R. McCLURE, P.E., R.P.L.S.
.• McCLURE ENGINEERING, INC.-------
January 2, 1996
TEXAS NATIONAL RESOURCE CONSERVATION COMMISSION
P.O. Box 13087
Austin, TX 78711-3087
Attn: Mr. Thomas W. Weber, Manager
WASTEWATER PERMITS SECTION
AGRICULTURE & WATERSHED MANAGEMENT DIVISION
RE: SHENANDOAH,PHASETHREE
COLLEGE STATION, BRAZOS COUNTY, TEXAS
Dear Mr. Weber:
As per TNRCC Regulations, attached for your review and approval, please find the
following items for the above referenced submittal for SHENANDOAH, PHASE THREE
subdivision construction in College Station, Texas:
1. ENGINEERING SEWERAGE REPORT
2. Specifications for Sanitary Sewer Construction
3. Plan Sheets 1, 5, 6, 7, S2 and S4 of the Construction Plans
We request that you review this application at your earliest convenience and provide the
required approval so that this project can be constructed upon completion of the City's approval
process.
We appreciate your assistance in this matter.
Veryt~ly~~
11~~
Michael R. McClure, P.E., R.P.L.S.
MRM/mln'l
xc: Mrs. Veronica Morgan, P.E.
Assistant City Engineer
CITY OF COLLEGE STATION
1722 Broadmoor , Suite 210 • Bryan , Texas 77802 • (409) 776-6700 • FAX (409) 776 -6699
TNRCC
TEXAS NATURAL RESOURCE CONSERVATION COMMISSION
GRAVITY LINE SUB MITT AL APPLICATION
FOR
PLANS AND SPECIFICATION REVIEW
SHENANDOAH, PHASE THREE
COLLEGE STATION, BRAZOS COUNTY, TEXAS
DECEMBER, 1995
PREPARED BY:
McCLURE ENGINEERING, 1:Nc.
1722 Broadmoor, Suite 21 '0
Bryan , Texas 77802
(409) 776-6700
TABLE OF CONTENTS
SHENANDOAH, PHASE THREE
I. ENGINEERING SEWERAGE REPORT
II. DESIGN OF BURIED PVC PIPE (TRENCH CONDITION)
III. TECHNICAL SPECIFICATIONS
NO . S102 -LEAKAGE TESTS
NO. S104 -POL YVINYLCHLORIDE PIPE AND FITTINGS
NO. S201 -MANHOLES
NO. WS306 -EXCAVATION
IV. PLAN SHEETS
PLAN SHEETS 1, 5, 6, 7, S2 AND S4
ENGINEERING SEWERAGE REPORT
INTRODUCTION
. The SHENANDOAH, PHASE THREE project is a proposed new phase of the existing
Shenandoah subdivision in southern College Station, Brazos County, Texas. The proposed 6"
sewer lines extend from existing the SHENANDOAH, PHASE TWO to service the proposed
residences in Phase Three.
GENERAL
The sewer will be owned and maintained by the City of College Station and will be
constructed with private funds. The line is designed by McClure Engineering, Inc. of Bryan,
Texas. The Engineer for the project is Michael R. McClure; P.E. (409) 776-6700. The
proposed sewer line is to be located within the rights-of-way of proposed streets and public
utility easements of the City of College Station. No part of the project is in the Edwards
Aquifer Recharge Zone. Sewerage flows from the line will flow to the existing waste water
treatment plant (Texas Natural Resources Conservation Commission (TNRCC) Permit #
10024006) ·operated by the City of College Station. This plant is currently not under an
enforcement order.
The project consists of 2068 L.F. of 6" sewer line (minimum slope 0.600%) and does
not require; any boring or other threnchless technology.
Per sheet one (1) of the construction drawings, the plans are superior to the technical
specifications. The design of the system ensures that full flow velocities will be greater than two
feet per second and less than ten feet per second. Per the genefal notes on sheet one of the
construction drawings, the City of College Station will provide inspection of the project and will
certify that the construction was performed substantially in accordance with the approved plans
and specifications. This project has been reviewed by the City of College Station.
CAPACITY
Capacity design for this line is based on service connections. The subdivision includes
forty-one (41) residential lots , with stub-outs provided for a total of nineteen (19) more
residential lots. Using the total of sixty (60) lots at 300 gallons per day (g .p.d.) with 103
infiltration and a peaking factor of four (4), the peak flow in this line is 79 ,200 g.p.d. (0.123
cubic feet per second (cfs)). A 6" PVC pipe with a Manning's "n " valve of 0.013 and minimum
slope of 0 .603 has a capacity of .40 cfs. Hence, the system has adequate capacity.
MATERIALS
The plans specify PVC pipe (ASTM D3034 , SDR 26). Per the specifications (S.104/1-
S104/5), these pipes are required to use joints per ASTM D3034-89. Manholes will be cast in
place or precast concrete per construction plan sheet S2 and Specification S.201/1-8 Item S.201.
These materials have been chosen to eliminate corrosive attack. Precast Manhole Bases requiring
resilient connects are not specified for this project. The City of College Station has recently been
allowing these bases provided they meet all City requirements including the resilient connector
per ASTM C-923.
The minimum manhole size is 48 " (inside diameter). All manhole lids are minimum 24"
in diameter. No drop manholes are required because no drops greater than 24" are designed.
2
' '
The soffit of the pipe is matched or a minimum of .1' of drop is provided to reduce turbulence.
Per TNRCC requirements, a channel is provided through the base of the manhole of a depth that
is at least one half the diameter of the pipe. The base outside of the flow channel is sloped at
12: 1 toward the channel. No manholes on this job are within a 100-year floodplain (per the
Federal Emergency Management Agency Flood Insurance Rate Map# 48041C0205C for Brazos
county, Texas and Incorporated Areas). All manhole access will be by ladder.
Low pressure air tests or Exfiltration tests will be required on all sewer line per the
specifications page S.102/1 Item S.102.2. Manholes may be tested using a Hydrostatic test per
the specifications page S.20116 Item S.201.7.1.
EMBEDMENT DESIGN
The design of the embedment for the flexible pipe is included as Table 1 of this report.
Note that the existing soil parameters are estimated by an experienced soils engineer familiar to
the area and proposed embedment soil parameters are per ASTM C2321.
Maximum and minimum trench widths are shown on sheet S 1 of the construction
drawings. The design allows for a minimum of eight inches (8") and a maximum of twelve
inches (12") on either side of the pipe. This requirement minimizes the trench width while
allowing for proper compaction of the material around the pipe. Trenches should be vertical for
a minimum of 12" above the pipe per the specification WS.306.B.1.b. The bedding material per
sheet S 1 of the constructions precludes the use of large stones or lumps in the backfill. No
unusual soil or geologic or hydrologic conditions are known to exist for this project. Sediment
and erosion control are shown on sheets 1 and 12.
3
' .
OTHER ITEMS
No horizonal or vertical curves are required for this work. Manholes are provided at all
ends of lines, and changes of grade or alignment. The maximum spacing of any manholes is
500' for all sizes of lines. The design of the system incorporates a minimum of 9' clearance
between water lines and sewer lines. Where this is not obtainable, a 20' joint of sewer pipe is
centered on the waterline to preclude cross connections. An 18" air gap is provided between the
elevation of all potable water outlets and the maximum water surface elevation of any sewer
appurtenances. The site does not contain any water wells, springs, surface water sources of
potable water, or potable water storage facilities. The storm drain system and sanitary sewer
system are designed to prevent storm water from entering the sewer system. The storm drain
system for this project is designed for the 10 year storm.
SUMMARY
The project is designed entirely within the TNRCC guidelines given in chapter 317 of the
Texas Water Code under the authority of sections 26.023 and 5.103.
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TABLE 1
DESIGN OF BURIED PVC PIPE (Trench Condition)
Common Data Deflection Analysis
. . ·-... Nominal Diameter 6 inches
w= 120 Wt. of Soil (lbs/cf) Be= 0.52 Outside D of Pipe (ft.)
k= 0.33 Rankine's Ratio Bd= 2.52 Trench Width (ft.)
u= 0.5 Coef. of friction H= 27 .89 Height of Cover (ft.)
P= 0 Single Wheel Load (lbs) ~d= ( 1-eA (-2 kuH/Bd)) /2ku: 2.95 no units
SOR 26 Dim. Ratio W c (in ital) =CdwBdBc= 467 lbs/If
E'b= 150 Bedding Mat. Modulus Wc(Prisim)=H w Be 1751 12.16 lbs/sf ps i
E'n= 150 Soil Mat. Modulus R= 0.262 Rad ius in ft.
K= 0.1 Bedding Constant HA2+RA2= 778 .16 ftA2
E= 4.00E +05 Elastic Mod. of Pipe Cl= (live load coefficent) 0.0003 0.001
hw 0 Depth of Water (inches) lf=.766-.133H= 0 no units
Wl=CI P (1 +lf)/12= 0 lbs/inA2
f=Pipe/Trench Width Coefficent
=b/da-1/(1.154 + .444(b/da-1 )= 1.34 no un its
zeta= 1.44/(f+ [( 1.44-f)*(Eb/En) 1 no units
Pipe Deflection
K (Lp+LI) 100/(.149 Ps+.061 zeta E'b 5.00 3
t= 0.02 0.24 ft inches
Ps= .559 E (t/r)A3 101.78 psi
Stiffness Check 11.12 >.15
. . . .. ·-· ...
Buckling Analysis
Rw= 1
B'= 0.605
I= 0.001 inA3 ftA3
qa= 29.69 ps i
qa= 12 .16 psi
Wall Crushing
T= 38 .1 5 lbs
Pc= 158 .04 psi
Page 1