LOS FRESNOS CITY HALL ADDENDUM 03 7/11/18 PAGE 1 OF 2 ADDENDUM NO. 03 PROJECT: LOS FRESNOS CITY HALL LOCATION: LOS FRESNOS, TEXAS PROJECT NO: 217072.00 DATE: July 11, 2018 The Construction Documents on the above referenced project, dated 6/11/18, shall be revised as follows: DRAWINGS Item No. 1 (RE: Sheet C1.3, Detail 3) - Thickness of concrete paving at concrete curb/gutter shall be 7” minimum. Thickness of asphalt paving is as follows: Asphaltic Concrete - 2” at parking areas, 2.5” at drives Crushed Limestone Base - 8” Chemically Stabilized Subgrade - 6” Item No. 2 (RE: Sheet C2.0, Utility Plan) - The sanitary sewer invert at the building is revised and additional slopes and elevations are noted as shown on attached revised sheet C2.0. The invert at the existing sewer tie-in is correct and will require dewatering, as noted in the revised sheet. Item No. 3 (RE: Sheet C4.0, Erosion Control Plan) - Some sewer information was unintentionally shown on the erosion control plan and is removed in attached revised sheet C4.0. Item No. 4 (RE: Sheet S0.0, Structural Steel Notes; Sheet S1.2, Detail 1) – Structural steel members which are exposed to the exterior shall be hot-dipped galvanized, specifically the HSS columns and beams at the drive thru canopy. Per the painting specifications, a paint compatible with galvanizing shall be used. Item No. 5 (RE: Sheet S1.1, Sheet S5.0) - Callouts for grade beam details are revised as shown in attached revised sheet S1.1. Grade beam details are revised and new details added as shown in attached revised sheet S5.0. Item No. 6 (RE: Sheet E1.1, Detail 1) – Additional push button locations for motorized door operators are added to the building interior as shown in attached revised sheet E1.1. SPECIFICATIONS Item No. 7 (RE: Section 00 00 10 Table of Contents, Section 00 30 00 Information Available to Proposers) – Attachment 00 30 00C Geotechnical Addendum Letter is added to the Table of Contents and the Project Manual, and is attached to this addendum. This addendum letter contains additional recommendations regarding subgrade stabilization which shall be followed in conjunction with the original Geotechnical Report. 7/11/18
Transcript
LOS FRESNOS C I TY HAL L ADDENDUM 03 7/11/18 PAGE 1 OF 2
ADDENDUM NO. 03
PROJECT: LOS FRESNOS CITY HALL
LOCATION: LOS FRESNOS, TEXAS
PROJECT NO: 217072.00
DATE: July 11, 2018
The Construction Documents on the above referenced project, dated 6/11/18, shall be revised as follows:
DRAWINGS
Item No. 1 (RE: Sheet C1.3, Detail 3) - Thickness of concrete paving at concrete curb/gutter shall be 7” minimum. Thickness of asphalt paving is as follows: Asphaltic Concrete - 2” at parking areas, 2.5” at drives Crushed Limestone Base - 8” Chemically Stabilized Subgrade - 6”
Item No. 2 (RE: Sheet C2.0, Utility Plan) - The sanitary sewer invert at the building is revised and additional slopes and elevations are noted as shown on attached revised sheet C2.0. The invert at the existing sewer tie-in is correct and will require dewatering, as noted in the revised sheet.
Item No. 3 (RE: Sheet C4.0, Erosion Control Plan) - Some sewer information was unintentionally shown on the erosion control plan and is removed in attached revised sheet C4.0.
Item No. 4 (RE: Sheet S0.0, Structural Steel Notes; Sheet S1.2, Detail 1) – Structural steel members which are exposed to the exterior shall be hot-dipped galvanized, specifically the HSS columns and beams at the drive thru canopy. Per the painting specifications, a paint compatible with galvanizing shall be used.
Item No. 5 (RE: Sheet S1.1, Sheet S5.0) - Callouts for grade beam details are revised as shown in attached revised sheet S1.1. Grade beam details are revised and new details added as shown in attached revised sheet S5.0.
Item No. 6 (RE: Sheet E1.1, Detail 1) – Additional push button locations for motorized door operators are added to the building interior as shown in attached revised sheet E1.1.
SPECIFICATIONS
Item No. 7 (RE: Section 00 00 10 Table of Contents, Section 00 30 00 Information Available to Proposers) – Attachment 00 30 00C Geotechnical Addendum Letter is added to the Table of Contents and the Project Manual, and is attached to this addendum. This addendum letter contains additional recommendations regarding subgrade stabilization which shall be followed in conjunction with the original Geotechnical Report.
7/11/18
LOS FRESNOS C I TY HAL L ADDENDUM 03 7/11/18 PAGE 2 OF 2
Item No. 8 (RE: Section 06 10 00 Rough Carpentry) - Article 1.05 is deleted in its entirety. LEED Forest Certification is not required for this project.
Item No. 9 (RE: Section 07 40 00 Metal Roof Panels) – Article 2.01, Paragraph A. Sub-paragraph 1 shall be replaced with the following: 1. MBCI “SuperLok”, or approved equal.
CLARIFICATIONS
Item No. 10 (RE: Sheet S0.0, Slab-on-grade Site Preparation Notes) – Cut and fill for the building pad shall extend out to the drive thru lanes to include the area underneath the drive thru column footings, as they are directly tied into the building’s structural system.
Item No. 11 (RE: Sheet A8.1, Detail 5; Section 10 14 00 Signage) – Article 2.04, Paragraph F. Specified manufacturer Gemini has indicated that the star medallions do not fit their production methods for either fabricated aluminum or cast aluminum. Preference is to use a different manufacturer that has the capability to produce the star medallions in the desired size and shape. If that is not possible, a flat cut metal medallion may be considered.
Item No. 12 (RE: Section 32 12 16 Bituminous Concrete Pavement) - Article 3.02, Paragraph G. A question was asked if the “flex base” needs to be stabilized as well. No, the flex base does not need to be stabilized.
SUBSTITUTIONS
Item No. 13 (RE: Section 10 22 26 Operable Partitions) – Article 2.01, Paragraph A. Kwik-Wall IS an acceptable manufacturer for operable partitions.
Item No. 14 (RE: Section 10 22 26 Operable Partitions) – Article 2.01, Paragraph A. Moderco IS an acceptable manufacturer for operable partitions.
NOTE: 1. REFERENCE PLANS FOR SLOPING SLAB CONDITIONS, TYP.2. WHERE SLAB DROP IS LESS THAN OR EQUAL TO 1 1/2", SLAB
REINF. MAY BE CONTINUOUS AND BENT BELOW DROP IN LIEU OF PROVIDING BENT BARS AS SHOWN.
3. VAPOR RETARDER AS DETAILED TO BE INSTALLED BELOW ALL FOUNDATION CONCRETE.
4. ALL SPLICES SHALL BE AS SPECIFIED IN THE GENERAL NOTES.
TY
P.
6"
MIN
.
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
12"
2" X 2" MASONRY
LEDGE
42"
4 1
/2"
#4 BARS @ 16" OCEW
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
12"
#4 BARS @ 16" OCEW
12"
1/2" EXPANSION JOINT W/ 1/2" SEALANT
#5x18" DOWELS @ 16" OC SLIP COVER ONE END
42"
#4 BARS @ 16" OCEW
4 1
/2"
(3) #6 BARS
(3) #6 BARS
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
#3 STIRRUPS @ 24" OC
12"
#4 BARS @ 16" OCEW
42"
4 1
/2"
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
#4 BARS @ 16" OCEW1
2"
MIN
.
4 1
/2"
12" MIN.
#3 BAR @ 24" OC
1
1
(2) #5 BARS
#5 BARS @ 8" OCEW TOP & BOTTOM
MA
X.
12"
24"
REF. PLAN
FLATWORK BY OTHERS
EMBED PLATE
NOTE: WIDENED PORTION OF FOOTING SHALL SIT BELOW FLATWORK. NARROWED PORTION OF FOOTING TO MATCH ARCHITECTURAL COLUMN BASE. COORDINATE ELEVATIONS OF COLUMN BASE AND TOP OF FOOTING WITH ARCHITECTURAL & CIVIL.
EQ EQ
REF. PLAN
#5 BENT BARS @ 8" OCEW
12" LONG, #4 DOWELS @ 12" OC. EXTEND MIN. 6" INTO FLATWORK.
SLIP COVER THIS END, TYP.
1/2" EXPANSION JOINT W/ 1/2" X 1/2" SEALANT
2"X 10" MASONRY LEDGE ALL AROUND
#5 STANDEES @24" OCEW, TYP.
(2) #5 X 36" BENT BARS TOP & BOTTOM
NOTES:1. PROVIDE CORNER BARS AS SHOWN AT ALL EXTERIOR
BEAM INTERSECTIONS.2. THIS IS A SCHEMATIC ONLY, SEE BEAM SECTIONS FOR
ACTUAL BEAM REINFORCEMENT. (SLAB NOT SHOWN)
(2) #5 X 36" BENT BARS TOP & BOTTOM
NOTES:1. PROVIDE CORNER BARS AS SHOWN AT ALL EXTERIOR
BEAM INTERSECTIONS.2. THIS IS A SCHEMATIC ONLY, SEE BEAM SECTIONS FOR
ACTUAL BEAM REINFORCEMENT. (SLAB NOT SHOWN)
SLAB REINF.
TOP BEAM REINF.
BOTTOM BEAM REINF.
STIRRUPS @ 24" OC
ALLOWABLE BEAM PENETRATION AREA WITHOUT
BEAM / REINFORCEMENT MODIFICATIONS
2" MIN.
BE
AM
DE
PT
H
3R
D
BE
AM
BO
TT
OM
3R
D
BE
AM
MID
DLE
3R
D
BE
AM
TO
P
DE
PT
H
BE
AM
RE
F. P
LA
N
BEAM REINF., TYP.
REF. PLAN
DEPTH
BEAM
#3 BENT BARS TO MATCH STIRRUP DEPTH @ 12" OC ALONG BENT BARS
TYP.
(30) BARØ
#5 BENT BAR, TOP & BOTTOM
RE
F. P
LA
N
WID
TH
BE
AM
RE
F. P
LA
N
BEAM REINF., TYP.
REF. PLAN
#3 BENT BARS TO MATCH STIRRUP DEPTH @ 12" OC ALONG BENT BARS
#5 BENT BARS, TOP & BOTTOM, TYP.
REF. PLAN
RE
F. P
LA
NR
EF
. P
LA
N
NOTE: FOR FOOTINGS WITH DIMENSIONS OF 1' -6", ONLY ONE (1) #5 BENT BAR NEED BE PROVIDED
BEAM REINF., TYP.
#3 BENT BARS TO MATCH STIRRUP DEPTH @ 12" OC ALONG BENT BARS
#5 BENT BARS, TOP & BOTTOM, TYP.
12"
2" X 10" MASONRY
LEDGE
42"
4 1
/2"
#4 BARS @ 16" OCEW
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
14"
2" X 2" MASONRY
LEDGE
42"
4 1
/2"
#4 BARS @ 16" OCEW
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
REF. PLAN
#5 BARS @ 8" OCEW TOP & BOTTOM
#4 BARS @ 16" OCEW
42"
CONTINUE BEAM REINF. THROUGH FOOTING
4 1
/2"
#5 STANDEES @24" OCEW
2"X10" MASONRY LEDGE
CONCRETE CURB TO TYP. INTERIOR SLAB ELEV.
#4 BARS @ 16" OCEW
REF. PLAN
42"#5 BARS @ 8"
OCEW TOP & BOTTOM
4 1
/2"
2"X10" MASONRY LEDGE
CONTINUE BEAM REINF. THROUGH FOOTING
CONCRETE CURB TO TYP. INTERIOR SLAB ELEV.
21 1/2"
#4 BARS @ 16" OCEW
42"
4 1
/2"
#5 BARS TOP & BOTTOM
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
BENT BAR TO MATCH BEAM REINF.
SLAB REINF.
TOP BEAM REINF.
BOTTOM BEAM REINF.
BEAM TIES @ 24" OC
PIPE PENETRATION AREA AT BOTTOM 3RD OF BEAM
2" MIN.
6" MIN. 6"
MIN
.
45.0
0° M
AX
.
BENT BARS TO MATCH BEAM REINF.
BE
AM
DE
PT
H
3"
MIN
.
3R
D
BE
AM
BO
TT
OM
3R
D
BE
AM
MID
DLE
3R
D
BE
AM
TO
P
6" MIN.SLAB REINF.
TOP BEAM REINF.
BOTTOM BEAM REINF.
BEAM TIES @ 24" OC
PIPE PENETRATION AREA AT TOP 3RD OF BEAM
6"
MIN
.
45.0
0° M
AX
.
(3) #6 BENT BARS
BE
AM
DE
PT
H
3"
MIN
.
3R
D
BE
AM
BO
TT
OM
3R
D
BE
AM
MID
DLE
3R
D
BE
AM
TO
P
2" MIN.MAINTAINSLAB DEPTH
(2) #6 BENT BARS
#5 BARS @ 8" OCEW TOP & BOTTOM
#4 BARS @ 16" OCEW
42"
CONTINUE BEAM REINF. THROUGH FOOTING
4 1
/2"
#5 STANDEES @24" OCEW
REF. PLAN
14"
42"
4 1
/2"
#4 BARS @ 16" OCEW
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
12"
4 1
/2"
42"
(3) #6 BARS
(3) #6 BARS
#3 STIRRUPS @ 24" OC
#4 BARS @ 16" OCEW
BENT BARS TO MATCH SLAB REINF.
2"X10" MASONRY LEDGE
12" MIN.
#4 BARS @ 16" OCEW
4 1
/2"
31" MIN.
#4 BENT BARS TO MATCH SLAB REINF.
SLAB RECESS, MAINTAIN REINF.
CLEARANCES 24" MAX.
1
1
4 1
/2"
INSTALL PRECUT BOOT OR SEAL AROUND PLUMBING PENETRATION WITH MANUFACTURER APPROVED TAPE OR MASTIC
SPLICE UNDER SLAB OR AT BOTTOM OF BEAM. OVERLAP
SPLICE 6" MIN. & TAPE WITH MANUFACTURER APPROVED TAPE
NOTE: VAPOR RETARDER AS DETAILED TO BE INSTALLED BELOW ALL FOUNDATION CONCRETE
FOR REPAIR OF DAMAGED AREAS LESS THAN THE WIDTH OF A SINGLE PIECE OF MANUFACTURER TAPE, TAPE MAY BE USED FOR REPAIR. FOR LARGER DAMAGED AREAS, CUT A NEW PIECE OF VAPOR RETARDER THAT EXTENDS A MINIMUM OF SIX INCHES BEYOND THE DAMAGE IN ALL DIRECTIONS AND CONNECT WITH TAPE
EXTERIOR BEAM W/ FOOTING & MASONRY LEDGE - BEAM LEFT
1
1
NO
.R
EV
ISIO
ND
AT
E
1A
DD
EN
DU
M 0
30
7.0
6. 1
8
UP
2
2
1
1
A
4
4
6
6
3
3
5
5
7
7
9
9
8
8
10
10
11
11
12
12
13
13
C
D
E
G
F
H
B
LOBBY
102
CORRIDOR
108
ECON. DEV.
OFFICE
106
C.O.C.
OFFICE
105
C.O.C.
OFFICE
104
WOMEN
110
MEN
109
JANITOR
112
STAIR
111
MUNICIPAL
COURT
113
COUNCIL
CHAMBER
114
AV EQUIP.
116
JURY
DELIB.
117
COURT
CLERKS
107
LOBBY
118
COMM.
HEALTH
119
CORRIDOR
120
SMALL
CONF.
121
IT DIR.
142
ADMIN.
ASST.
123
RESTROOM
131
RESTROOM
132
CITY
SECRETARY
124
FILES
125
PUBLIC
WORKS DIR.
127
ADMIN.
ASST.
129
CONFERENCE
128
CORRIDOR
133
ACCT.
CLERK
134
ACCT.
CLERK
138
FINANCE
DIRECTOR
137
FINANCE
STOR.
139
ACCTS.
PAYABLE
135
JANITOR
136
SERVER
141
BREAK
ROOM
140
ELEC.
122
CASHIER
144
BILLING
CLERK
143
E.O.C.
STORAGE
103
CITY
MANAGER
126
VESTIBULE
101
SPKLR.
RISER
145
MAIL
130
CORR.
115
S S
JJJ
J
RE: 3/E1.1 FORENLARGED PLAN
PROJECTOR(CEILINGMOUNTED)MOTORIZED DROP
DOWN SCREEN(CEILING MOUNTED)
MOTORIZED DROPDOWN SCREEN(CEILING MOUNTED)
PROJECTOR(CEILINGMOUNTED)
PRINTER
COPIER
TELLER UNITS
REF MICR
COPIER
FAX
PLOTTER
WP WP
WP
WP
WP
IRRIGATIONCONTROL
J
J
S
J S
5E1.1
4E1.1
LA-1
LA-3
LA-2
LA-8
LA-10
LA-4
LA-26 LA-28
LA-34
LA-24
LA-36
LA-20
LA-12
LA-6
LA-16
LA-22
LA-18
LA-38
LA-50
LA-48
LA-40
LA-44
LA-42
LA-7
LA-9
LA-11
LA-13
LA-15
LA-17
LA-19
LA-21
LA-23
LA-25
LA-27
LA-29
LA-31LA-37
LA-33
LA-39 LA-41 LA-43LA-45
LA-47
LA-49LA-51
1
2
2
2
2
3
LA-57
LA-57
LA-59
LA-59
LA-53
LA-53
LA-55LA-55
LA-55
LA-46
LA-61
LA-63
5
5
5
WP
WP
WP WP
WP
WP
WP
LA-14
LA-35
6
6
1
LA-86
LA-79
3/4" CONDUIT WITH PULL STRING FROM 48" A.F.F.
J
J 7
7
LA-5J
J
LA-817
7
LA-83
LA-30
LA-32
JJ LA-88WPJ J
J
J
J
J
(TYP 8)
J
LA-92AIR COMPRESSOR(DRY PIPE SYSTEM) 9
1
J
J
J
J
8
COUNCIL
CHAMBER
114
J
J
J
J
J
J
J
J
LOCATED INMILLWORK(TYP)
SYSTEMSFURNITURE FEED.FOR 5 STATIONS.
LA-52
LA-54
LA-56
LA-58
LA-60
LA-62
LA-64
4
LA-66
ELEC.
122
MDP
LA (3-SEC)
TC
LM(2-SEC)
LA-15
ATS
DFC
2
(SERVEDFROMDCU-2)
SERVER
141
+44"+44"
J
J
J
J
LA-65 LA-67
LA-68/70
LA-72/74
LA-76/78
LA-80/82
DFC
1
(SERVEDFROMDCU-1)
1. REFER TO SHEET E0.1 FOR GENERAL ELECTRICAL NOTES.
2. REFER TO SHEET E2.1 FOR FIRE ALARM PLAN.
2. REFER TO SHEET E2.1 HVAC/PLUMBING PLAN.
3. REFER TO SHEET E0.2 FOR PANEL SCHEDULES.
4. ALL OUTDOOR EQUIPMENT SHALL BE GFCI/WP.
5. ALL ABOVE COUNTER ELECTRICAL RECEPTACLES SHALL BE MOUNTED +42" AFF,UNO.
6. REFER TO ARCHITECTURAL DRAWINGS FOR EXACT HEIGHT AND LOCATION OFALL FLOOR AND WALL RECEPTACLES. REFER TO ARCHITECTURAL DRAWINGSFOR VERTICAL OR HORIZONTAL INSTALLATION OF ALL RECEPTACLES.
7. COORDINATE ROUTING OF ALL CONDUCTORS AND CONDUIT WITH EXISTING FIELDCONDITIONS AND OTHER TRADES.
8. DRAWINGS ARE DIAGRAMMATIC AND SHALL NOT BE USED FOR EXACTDEVICE/OUTLET LOCATIONS. THE CONTRACTOR SHALL OBTAIN ALL NECESSARYDIMENSIONS FOR ANY EXACT TAKEOFFS FROM THE ARCHITECT.
GENERAL NOTES:
KEY NOTES:
JUNCTION BOX AND DEDICATED RECEPTACLE FOR TELLER UNIT AND A/V UNIT.ROUTE PNEUMATIC TUBE FROM TELLER UNIT IN CASHIER ROOM 144 TO CUSTOMERUNIT THROUGH ABOVE CEILING. COORDINATE EXACT LOCATION AND MOUNTINGREQUIREMENTS WITH PNEUMATIC TUBE SYSTEM VENDOR.REFER TO PNEUMATICTUBE SYSTEM DRAWINGS FOR MORE INFORMATION.
FURNISH AND INSTALL SOFFIT-MOUNTED DUPLEX RECEPTACLE FOR CHRISTMASLIGHTS. CONTROLLED VIA PROGRAMMABLE TIME SWITCH AS INDICATED ON PLANS.
JUNCTION BOX AND DEDICATED 120V, 20A CIRCUIT ROUTED UNDERGROUND IN 3/4"C. FOR CUSTOMER UNIT. COORDINATE EXACT LOCATION(S) AND MOUNTINGREQUIREMENTS WITH PNEUMATIC TUBE SYSTEM VENDOR. REFER TO PNEUMATICTUBE SYSTEM DRAWINGS FOR MORE INFORMATION.
FURNISH AND INSTALL WIREMOLD WALLSOURCE BOX MOUNTED IN VERTICALMILLWORK IN FRONT OF COUNCIL DESKS WITH (1) DUPLEX RECEPTACLE, (2) DATA,(1) MICROPHONE OUTLETS. REFER TO SHEET T1.1 FOR MORE DETAILS. COORDINATEFINISH TYPE WITH ARCHITECT PRIOR TO PROCURMENT.
FURNISH AND INSTALL LEGRAND WIREMOLD OMNIBOX 880S2 SERIES FULLYADJUSTABLE RECESSED CONCRETE 2 GANG, MULTIPLE SERVICE CAST IRON FLOORBOX EQUIPPED WITH FLANGE AND COVER PLATE ASSEMBLY EQUIPPED WITH QUADELECTRICAL RECEPTACLE AND VOICE/DATA CONNECTIONS. COORDINATE EXACTFINISH AND FLOOR TYPE WITH ARCHITECT PRIOR TO PROCURING EQUIPMENT.FURNISH AND INSTALL TWO (2) 1” CONDUIT ROUTED FROM FLOOR BOX TO NEARESTWALL UP TO AN ACCESSIBLE LOCATION ABOVE CEILING. COORDINATE EXACTLOCATION OF FLOOR BOXES WITH ARCHITECT AND MILLWORK CONTRACTOR PRIORTO COMMENCEMENT OF WORK.
COORDINATE POWER REQUIREMENTS WITH SIGNAGE INSTALLER PRIOR TOCOMMENCEMENT OF WORK.
POWER FOR AUTOMATIC FLUSH VALVES, COORDINATE WITH PLUMBING PRIOR TOCOMMENCEMENT OF WORK.
PROVIDE 120V, 20A CIRCUIT FOR PUSHBUTTONS FOR MOTORIZED DOOROPERATORS.
PROVIDE 120V, 20A CIRCUIT FOR POWER TO AIR COMPRESSOR (DRY PIPE SYSTEM).COORDINATE EXACT LOCATION AND POWER REQUIREMENTS WITH SPRINKLERCONTRACTOR.
COLLEGE STATION 979 680 8840 BRENHAM 979 836 6855 FORT WORTH 817 405 0774 SAN ANTONIO 210 305 4792
2501 Ashford Drive, Suite 102 / College Station, Texas 77840 Fax 979 680 8841 www.gessnerengineering.com CIVIL STRUCTURAL GEOTECHNICAL LAND SURVEYING CONSTRUCTION MATERIALS TESTING
July 10, 2018 Mr. Ray Holliday, AIA Brown Reynolds Watford Architects 2700 Earl Rudder Freeway South, Suite 4000 College Station, Texas 77845 Re: Geotechnical Engineering Study – Addendum Letter 2 Los Fresnos Municipal Complex Highway 100 Los Fresnos, Texas Gessner Engineering Job No. 17-0424
Dear Mr. Holliday:
Gessner Engineering was requested to provide an addendum letter to address changes in pavement subgrade treatment recommendations for the proposed Los Fresnos Municipal Complex located in Los Fresnos, Texas. This letter is an addendum to the original Los Fresnos Municipal Complex Geotechnical Report, dated October 17, 2017, the Los Fresnos Municipal Complex Supplementary Letter, dated March 19, 2018, and the Los Fresnos Municipal Complex Addendum Letter, dated June 12, 2018. No additional field or laboratory testing was performed in conjunction with this addendum letter. This letter should not be used separately from the original report.
Subgrade Treatment
The type of subgrade treatment to stabilize soils on the site depends on the type of soil located under pavements. Lime stabilization works by reacting chemically with clay, but it does not react properly with sand. Therefore, it is recommended that lime be used to stabilize expansive clayey material and cement be used to stabilize sandy material. Subgrade treatment will add a structural component to the pavement section, and it is also recommended to provide a weather-resistant and workable surface for construction activity. It should be noted that stabilization recommendations are based on current grades. Should the site grading modify the surficial soils, variations from anticipated stabilization may be required.
Soils at this site are plastic and can be difficult to work with, particularly during periods of inclement weather. To provide a suitable, weather-resistant working surface for construction activity, the upper 6 inches of the plastic subgrade clays shall be treated with hydrated lime.
Lime treatment of the subgrade soils should be in accordance with the TxDOT Standard Specifications, Item 260. A sufficient quantity of hydrated lime should be mixed with the subgrade soils to reduce the soil-lime mixture PI to 18 or less. For estimating purposes, it is recommended that 8 percent lime by weight be assumed for treatment. For construction purposes, it is recommended that the optimum lime content of the subgrade soils be determined by laboratory testing. Lime-treated subgrade soils should be compacted to a minimum of 95 percent of the maximum density at a moisture content within the range of optimum moisture content to 3 percentage points above the optimum moisture content as determined by Tex-114-E.
GESSNER ENGINEERING CIVIL STRUCTURAL GEOTECHNICAL LAND SURVEYING CONSTRUCTION MATERIALS TESTING
It is recommended to perform additional laboratory testing to determine the concentration of soluble sulfates in the subgrade soils, in order to investigate the potential for a recently reported adverse reaction to lime in certain sulfate-containing soils. The adverse reaction, referred to as sulfate-induced heave, has been known to cause cohesive subgrade soils to swell in short periods of time, resulting in pavement heaving and possible failure.
It is important that proper perimeter drainage be provided so that infiltration of surface water from unpaved areas surrounding the pavement is minimized, or if this is not possible, curbs should extend through the base and into the subgrade. A crack sealant compatible to both asphalt and concrete should be provided at concrete-asphalt interfaces. It should be noted that post-construction subgrade movements and cracking of asphaltic pavements is not uncommon for subgrade conditions such as those observed at this site.
It has been a pleasure to provide you this supplemental information. If I can be of further assistance to you with this situation please contact me.
Sincerely, GESSNER ENGINEERING, LLC F-7451 Kristina M. Surber, P.E.
