ESBD_File_352743_24-17 Add2.pdf

501 N. Thompson Suite 405 Conroe, Texas 77301

GILBERT D. JALOMO, JR., CPPB

OFFICE OF COUNTY PURCHASING AGENT

MONTGOMERY COUNTY

ADDENDUM#2

Date: 3/25/24

936.539.7980

FAX: 936.760.6976

www.mctx.org

Project Title: Public Improvements for the Porter Heights Community for Precinct 4

Project No: 24-17

Opening Date: 04/03/24

NOTE CHANGES: The change/clarification in this addendum is as follows:

• Approximate budget for this project is $6 million.

• See attached documents o Questions and Answers.

o Geologic Fault and Geotechnical Study o Scope of Work replacement page 2 o Bid Form replacement page 1 o Plan sheet General Notes replacement Sheet No. 03 of 102

The bid opening date will remain the same. Deadline to turn in bids is 2:00 p.m.

This addendum forms a part of the Contract Documents and modifies the original specifications, issued for Montgomery County on March 6, 2024 to the extent noted hereinafter. Careful note of this Addendum will be taken by all parties of interest so that proper allowance is made in all computations, estimates and Contracts and so that all trades affected are fully advised in the performance of work that will be required by them. 1bis Addendum supersedes all previous Specifications and instructions pertaining to these items. It is imperative the bidder/proposer acknowledges receipt of this Addendum., by signing this document and returning it by fax within 24 hours after receipt or by including a signed copy with the bid/proposal packet.

Company Name Signature Date

Assistant County Purchasing Agent

Addendum 2 Project 24-17

Public Improvements for the Porter Heights Community Montgomery County Precinct 4

Questions & Answers

Project 24-17

1. Question: Will the tree removal be done by others as stated in the legend or is it the bidder’s responsibility to remove the trees called out in the plans? There is a conflicting note in the general notes (Note 17) and in the legend (Note 10).

Answer: Tree removal will be completed by Montgomery County. Plans to be updated to remove note 17 from general notes.

2. Question: The contractor calls for 165 calendar days for a total duration, but the monthly traffic control bid item shows a duration of 12 months. Please clarify the contractor duration.

Answer: The contract will be updated to read as 165 business days. The monthly traffic control bid item will be appropriately revised to 9 months to cover the 165 business days.

3. Question: Will MBE and SBE subcontractors be allowed for use to reach the 4% DBE goal?

Answer: Yes, they will be allowed. DBE firms must have the appropriate certification.

4. Question: Is there a geotechnical report available for this project?

Answer: The geotechnical report titled ‘Desktop Geologic Fault and Geotechnical Study Asphalt Pavement Improvement at Porter Height Community, Montgomery County, Texas, Project No. 23-787E,’ Prepared by Geotech Engineering and Testing and dated December 2023, is available for this project and can be provided.

5. Question: Will there be a bid item added for removal of the existing asphalt surface and base?

Answer: Item #105 includes the removal of both roadway and driveway asphalt surface and base. The item has been updated to incorporate the removal of the roadway asphalt.

6. Question: Will the contractor be held to only building 300 linear feet of roadway at a time as indicated in the phasing plan?

Project 24-17

Answer: For safety considerations, the 300-foot limits the length of two-way traffic on a single lane. However, the contractor is allowed to construct more than 300 LF of roadway at a time, provided they strictly adhere to the detour plans outlined in the Traffic Control Plan (TCP). It is imperative that adjacent, conflicting work areas are not constructed simultaneously to avoid conflicting traffic movements.

7. Question: Will the use of cement slurry be acceptable in lieu of dry cement?

Answer: Cement slurry is acceptable.

8. Question: The bid items indicate using flexible base for the 6”-8” base on all streets, however the typical sections call out using black base. Which one are we to figure?

Answer: The contractor shall follow the recommendations outlined in the geotechnical report to utilize a black base. The bid items will be updated to specify black base.

9. Question: There is currently no 400 item for the cement stabilized sand around the RCP, should that material be considered subsidiary to the pipe item?

Answer: Bid form will be updated to include item 400 cement-stabilized sand for backfill of RCP crossing beneath/crossing the asphalt roadway. Cement stabilized sand not to be used as backfill for driveway culverts.

10. Question: The driveways are 6” #4 12 OC with HES. Do you want to use the TxDOT spec for HES concrete?

Answer: If the contractor plans on using HES concrete, HES concrete shall follow TxDOT spec. Otherwise, please follow TxDOT spec for standard reinforced concrete pavement.

11. Question: The current phasing plans shows a large number of phases, can these be combined?

Answer: The contractor can establish multiple work zones, provided that the work zones are non-adjacent and do not impede the traffic flow as detailed in the detour plan within the TCP.

12. Question: On the flex base, is crushed concrete an acceptable flex base if it meets the TxDOT 247 TY D spec.

Answer: The base shall be black base as recommended in the geotechnical report.

Project 24-17

13. Question: Are there any additional details for the water lines?

Answer: Contractor shall follow the following City of Houston Details for water lines items:

02085-03 VALVE BOX DETAIL

02512-01 TYPICAL ¾” THROUGH 2” SERVICE ARRANGEMENTS

02512-02 SERVICE TAPS

02526-10 TYPICAL SERVICE LINE AND ARISER PIPING TO METER

VAULTS

02520-01 STANDARD FIRE HYDRANT DETAIL

DESKTOP GEOLOGIC FAULT AND GEOTECHNICAL STUDY

ASPHALT PAVEMENT IMPROVEMENT AT

PORTER HEIGHTS COMMUNITY

MONTGOMERY COUNTY, TEXAS

PROJECT NO. 23-787E

TO

R. G. MILLER ENGINEERS

HOUSTON, TEXAS

BY

GEOTECH ENGINEERING AND TESTING

SERVICING

TEXAS, LOUISIANA, NEW MEXICO, OKLAHOMA

DECEMBER 2023

TEXAS BOARD OF PROFESSIONAL ENGINEERS

REGISTRATION NUMBER F-001183

www.geotecheng.com

Addendum 2

GEOTECH ENGINEERING and TESTING

Geotechnical, Environmental, Construction Materials, and Forensic Engineering

R. G. Miller Engineers Project No. 23-787E

16340 Park Ten Place, Suite 350 Report No.: 1

Houston, Texas 77084 Project Type: 13/33

December 6, 2023

Attention: Mr. Alberto Espinoza, P.E.

Project Manager

DESKTOP GEOLOGIC FAULT AND GEOTECHNICAL STUDY

ASPHALT PAVEMENT IMPROVEMENT AT

PORTER HEIGHTS COMMUNITY

MONTGOMERY COUNTY, TEXAS

Gentlemen:

Submitted here is Geotech Engineering and Testing (GET) geotechnical study for the above referenced project. The planned improvements to the existing asphalt pavement were discussed in detail with Mr.

David Kubala, P.E. in order to plan a study that would provide the necessary rehabilitation

/reconstruction recommendations. This study was conducted in general accordance with GET Proposal

No. P23-277, dated September 27, 2023. Authorization to proceed with this study was received and was signed by Mr. Jack P. Miller, P. E., Chief Executive Officer, on October 24, 2023.

This report presents the results of our observations during field visit, geotechnical field exploration and laboratory testing together with the rehabilitation/reconstruction of existing asphalt pavement along

Porter Lane, Alexander Lane, Duester Lane, Bobby Lane, Jerry Lane, and Louis Lane, Montgomery

County, Texas.

ACCREDITED

CERTIFICATE #0075-01

#0075-02

17407 US Highway 59 North • Houston, Texas 77396 • Tel.: 713-699-4000 • Fax: 713-699-9200

Texas • Louisiana • New Mexico • Oklahoma

Website: www.geotecheng.com

Addendum 2

We appreciate the opportunity to be of service. Should you have any questions or need additional assistance, please call.

Very truly yours, TBPE Registration Number F-001183

Mason Derakhshandi, Ph.D., P.E.

Project Manager

James Namekar, Ph D., P.E.

Chief Engineer

MD/JN/DAE/md

Copies Submitted: (1) Hard Copy – R. G. Miller Engineers – Mr. Alberto Espinoza, P.E.

(1) PDF Copy Email – Mr. Alberto Espinoza, P.E.

(1) PDF Copy Email – Mr. David Kubala, P.E.

12-08-2023

Addendum 2 Project 24-17 https://geotecheng-my.sharepoint.com/personal/nikolas_geotecheng_com/Documents/Book1.xlsx?web=1 ii

TABLE OF CONTENTS

PAGE

1.0 EXECUTIVE SUMMARY

2.0 INTRODUCTION

3.0 DESKTOP GEOLOGIC FAULT STUDY

3.1 Site Conditions

3.2 Site Geology

3.3 Desktop Geologic Fault Study

4.0 FIELD EXPLORATION

4.1 Pavement Coring

4.2 Drilling and Sampling

5.0 LABORATORY TESTING

5.1 General

5.2 Classification Tests

5.3 Particle Size Analysis Tests

5.4 Strength Tests

5.5 Soil Sample Storage

6.0 SUBSURFACE SOIL AND GROUNDWATER CONDITIONS

6.1 Site Conditions

6.2 Soil Stratigraphy

6.3 Soil Properties

6.4 Water-Level Measurements

7.0 PAVEMENT DESIGN

7.1 General

7.2 Traffic Information

7.3 Recommended Subgrade Design Values

7.4 Design Parameters and Pavement Recommendations

7.5 Soil Stabilization

7.5.1 General

7.5.2 Subgrade Stabilization for Cohesionless

7.6 Rehabilitation

7.6.1 Full-Depth Reclamation (FDR)

7.6.2 Mill and Overlay 14

8.0 ROADSIDE DITCHES

8.1 General

8.2 Recommended Drainage Ditches Slope Ratio

8.3 Drainage Ditches Slope Erosion Protection

9.0 CONSTRUCTION CONSIDERATIONS

9.1 Surface Water Drainage

9.2 Site Preparation

9.3 Suitability of On-Site Soils for Use as Fill

9.3.1 General

9.3.2 Select Structural Fill

9.3.3 Structural Fill

9.3.4 General Fill

9.3.5 On-Site Fill Soil Classification

9.4 Earthwork

Addendum 2 iii

9.4.1 General

9.4.2 Improving Drainage

9.4.3 Subgrade Drying

9.4.4 Soil Mixing

9.4.5 Removal and Replacement

9.4.6 Modification/Stabilization

9.5 Construction Surveillance

10.0 RECOMMENDED ADDITIONAL STUDIES

11.0 STANDARD OF CARE

12.0 REPORT DISTRIBUTION

13.0 REFERENCES

ILLUSTRATIONS

Plate

Site Vicinity Map 1

Plan of Borings 2

Soil Stratigraphy Profile 3 – 5

Faults in the Harris County Area 6 – 7

Existing Pavement Thickness 8

APPENDICES

Appendix A – Plan of Borings, Logs of Borings, Key to Log Terms and Symbols

Appendix B – Pictures of Field Explorations

Appendix C – Particle Size Distribution Curves

Appendix D – Pavement Design Computations

Project No. 23-787E 1

1.0 EXECUTIVE SUMMARY

It is planned to improve existing asphalt pavement at the Porter Heights Community, Montgomery

County, Texas. The roads that will be included in this project are Alexander Lane, Duester Lane, Bobby

Lane, Jerry Lane, and Louis Lane. We understand that the planned improvements may include (a) replacing parts of existing two-lane asphalt roadways with new two-lane asphalt road, (b) milling the existing paving and replacing it with a new asphalt surface course and (c) conducting Full Depth

Reclamation (FDR). A site vicinity map of the project site is presented on Plate 1.

A field visit was conducted by Dr. Mason Derakshandi, Project Manager at GET on October 19, 2023.

During our field visit, we observed asphalt pavement cracking at multiple locations of the asphalt roads.

The purpose of our study was to explore the subsurface conditions along the project alignments. The information obtained was used to develop recommendations and to guide design and reconstruction/rehabilitation of existing asphalt pavement.

During our field visit to the project alignments, we observed asphalt pavement cracks at multiple locations of the asphalt roads. Upon analyzing core samples from the pavement and the underlying surface soil layer, it became evident that there is an absence of subgrade stabilization, and in some cases, inadequate base course thickness. The current study outlines crack prevention/mitigation.

The subsoils and groundwater conditions along the project alignments were explored by conducting twenty-nine (29) soil test borings (B-1 through B-29) at the request of client. Results of our field investigation and engineering analyses are summarized below:

1. In general, based on our field exploration and laboratory test data, the soils along the project alignments appear to be variable. The soils stratigraphy along the project alignments is summarized as follows:

Stratum

No.

Range of

Depth, ft.

Soil Description*

– 0.15 – 0.92 ASPHALT PAVEMENT (1.75-inch to 11-inch in thickness)

– 0.15 – 1 FLEXIBLE BASE (1-inch to 8.5-inch in thickness)

I 0.42 – 2 SILTY SAND (SM), light brown to dark brown, brownish yellow, light gray to dark gray, with root fibers to 2’, ferrous nodules, gravels

II 0.42 – 1 SANDY SILT (ML), dark brown, dark gray, with root fibers to 1’

III 2 – 10 LEAN CLAY (CL), soft to very stiff, light brown to dark brown, reddish brown, brownish yellow, light gray to dark gray with root fibers to 10’, ferrous nodules, gravels, sand seals and layers

2. Water level observations were made during and 0.33-hour after drilling. Our short-term field exploration indicates that groundwater was not encountered during and after drilling. However, the groundwater may rise during the wet season.

Project No. 23-787E 2

3. In order to recommend pavement component thickness for asphalt pavement reconstruction, the proposed pavement was designed on the basis of 1993 AASHTO Guide for Design of Pavement

Structures. Based on the information provided by the client, estimated design ESALs of 10×106 were used to calculate thicknesses of the flexible pavements for this project over a design life period of 20 years. The recommended pavement component thicknesses during reconstruction are summarized as follows:

Design, ESAL

Asphalt Pavement

Thickness, inch(es)

Crushed Limestone Base

Thickness, inch(es)

Subgrade Stabilization

Thickness, inch(es)

10× 106 3.0 12.0 16.0

Our field and laboratory tests indicate that the surficial soils consist of silty sand (SM) and sandy silt (ML) soils. The subgrade preparation in pavement areas should specify compaction of the upper eight-inch to at least 95% of maximum standard Proctor density (ASTM D 698) at a moisture content between optimum and ±2% of optimum moisture content.

Instead of crushed limestone base course, black base can also be considered along with Hot mix hot-laid asphaltic concrete with subgrade stabilization as shown below:

Thickness, inch(es)

Black Base Course

Thickness, inch(es)

Subgrade Stabilization

10× 106 2.0 8.0 10.0

4. For the local streets with light traffic at Porter Heights Community, the recommended pavement thickness during reconstruction in accordance with Montgomery County Subdivision Rules and

Regulations are summarized below:

Crushed Limestone Base

Thickness, inch(es)

Subgrade Stabilization

2.0 8.0 6.0

Black Base Course

Thickness, inch(es)

Subgrade Stabilization

2.0 6.0 6.0

5. The subgrade soils should be stabilized using Lime-Fly Ash. Use 2% lime and 8% fly ash by dry weight. This results in application rates of approximately 12 pounds of lime and 48 pounds of fly-ash per square yard for each eight-inches of compacted thickness. The fly ash stabilization should be in accordance with Texas Department of Transportation (TxDOT) Specification, Item

265.

In the event lime-fly ash is not available, cement can be used to stabilize the subgrade soils. The ratio of cement to soil should be generally about 8% percent by dry weight. The subgrade should be treated in accordance with TxDOT Standard Specification Item 275 for cement treatment.

Project No. 23-787E 3

6. A rehabilitation method, Full-Depth Reclamation (FDR) of asphalt pavement may be cost-effective. This method involves recycling existing asphalt pavement and its underlying layer(s) into a new base layer. The FDR process begins with using a road reclaimer to pulverize an existing asphalt pavement and a portion of the underlying base, subbase, and/or subgrade. The result is a stiff, stabilized base that is ready for a new rigid or flexible surface course. This system will not carry the design traffic loading of 10× 106 ESAL. In the case of using Full-Depth

Reclamation (FDR), the recommended thicknesses of pavement components during rehabilitation are summarized in this report. The proposed FDR sections may result in raising the existing pavement elevations. We recommend some of the FDR soils be removed to attain the design elevations. This may change the pavement section requirements.

7. Milling and overlaying the existing asphalt layer is another method included in this report. In this method, the asphaltic concrete surface layer should be milled to its full depth or greater to accommodate the placement of the new HMAC surface course. We recommend a minimum of 2 inches of new HMAC surface course be overlaid on top of the pulverized existing pavement materials. This system will not carry the design traffic loading of 10× 106 ESAL.

8. GET conducted a literature review and remote sensing study, as known as a desktop review, in accordance with the Houston Geological Society Bulletin technical article entitled "Investigation of Surface Faults in Texas Gulf Coast Region". Our review of fault maps indicates that there are no major active faults located at the project alignments. However, faults may be present that are absent from the published maps.

2.0 INTRODUCTION

It is planned to improve existing asphalt pavement at the Porter Heights Community, Montgomery

County, Texas. The roads that will be included in this project are Alexander Lane, Duester Lane, Bobby

Lane, Jerry Lane, and Louis Lane. The project vicinity map is presented in Plate 1. The plan of borings for the project alignment is presented on Plates 2 and A-1. We understand that the planned improvements may include (a) replacing parts of existing two-lane asphalt roadways with new two-lane asphalt road, (b) milling the existing paving and replacing it with a new asphalt surface course and (c) conducting Full Depth Reclamation (FDR).

The purpose of our study was to explore the subsurface conditions along the project alignments. The information obtained was used to develop recommendations and to guide design and reconstruction/rehabilitation of existing asphalt pavement based on AASHTO 1993 Guide of Design of

Pavement Structure (Ref. 2).

This report presents the results of our observations during site visit, geotechnical field exploration and laboratory testing together with the reconstruction/rehabilitation of existing asphalt pavement Porter

Lane, Alexander Lane, Duester Lane, Bobby Lane, Jerry Lane, and Louis Lane, Montgomery County, Texas. The pavement design in this study is generally in accordance with AASHTO 1993 Guide of

Design of Pavement Structure (Ref. 2).

Project No. 23-787E 4

3.0 DESKTOP GEOLOGIC FAULT STUDY

3.1 Site Conditions

The project alignments exhibit a topographic variation of less than four-ft. Currently, the project alignments are covered with asphalt pavement, except for the small part of Porter Lane at the intersection of FM 1314, which was covered with fill soils. In general, the area along the project alignments consists of residential and commercial facilities. Pictures of the project alignments were taken during our site visit and are presented on the cover page and in Appendix B.

3.2 Site Geology

According to the soil survey of Montgomery County, Texas (prepared by USGS), the project alignments are geologically located on Beaumont Formation, Willis Formation, Lissie

Formation, Fleming Formation, Alluvium, Deweyville Formation, and Terrace deposits

Association. The geologic character of the soil types is described in the following sections.

Beaumont Formation, areas predominantly sand (from Moore and Wermund, 1993a, 1993b):

Yellowish- to brownish gray, locally reddish orange, v. fine to fine quartz sand, silt, and minor fine gravel, intermixed and interbedded. Includes stream channel, point-bar, cravasse-splay, and natural levee ridge deposits, and clayey fill in abandoned channels. Forms poorly defined meander-belt ridges and pimple mounds aligned approx. normal to coast and 1-2 m higher than surround interdistributary silt and clay. Channel fill is dk-brn to brnish-dark-gray, laminated clay and silt, organic -rich. Includes marine delta-front sand, lagoonal clay, and near-shore marine sand beneath and landward of bays along the coast. Interfingers with the interdistributary facies of Beuamont Fm. and rests disconformably on Lissie Fm. Thickness 3-10 m on outcrop; thickens in southeastward in subsurface to more than 100 m.

Willis Formation: Clay, silt, sand, siliceous granule to pebble gravel, some petrified wood; sand coarser than younger units, noncalcareous; deeply weathered, locally cemented by iron oxide;

fluvitile; forms north-facing scarp. On Seguin Sheet (1974) thickness 100+- ft. On Austin 4 x 6-degree sheet (Moore and Wermund, 1993) unit consists of 1) channel facies--alluvial pebble gravel and sand, lt. gray to orange-brown, orange, gravelly coarse to fine sand which lenses of red, sandy silt and white to gray clay 10-60 m thick, pebbles mostly quartz, some chert and petrified wood, and 2) overbank facies--alluvial silt and clay made of brown, yellow, orange, fine silt and clay are intermixed and interbedded. 5-50 m thick.

Project No. 23-787E 5

Lissie Formation: Sand, silt, clay, and minor amount of gravel. Iron oxide and iron-manganese nodules are common in zone of weathering; locally calcareous. Surface fairly flat and featureless except for many shallow depressions and pimple mounds. Moore and Wermund (1993a) mapped three units--(1) alluvium undifferentiated as to texture and origin--includes meander belt, levee, crevasse splay, and distributary sand, and flood-basin mud deposits, about 60 m thick, (2) fine-grained channel facies (alluvial sand, silt, and clay) about 10-25 m thick, thicker seward, and (3) fine-grained overbank facies (alluvial silt and clay) about 55-65 m thick, thicker seaward.

Together, these deposits form a deltaic plain that parallels the Gulf Coast. Unit contains

Pleistocene vertebrate fauna, dips seaward beneath the Beaumont Fm. and disconformably overlies deposits of the Pliocene and early Pleistocene Willis Formation. The deltaic plain is entrenched as much as 7 m by streams. In Hidalgo County (southernmost part of Texas) the unit underlies a semiarid plain, widely irrigated and cultivated. The unit is locally veneered with thin, discontinuous stabilized eolian sand.

Fleming Formation: Clay and Sandstone. Clay, calcareous, forms brownish-black soil. Sandst.

med. to coarse grained, calcar., thick bedded, some crossbedding. lt. yell-gray; weathers lt. gray to med. gray; reworked Cretaceous invertebrate fossils locally. Thickness 1200+ ft.

Alluvium: Alluvium and low terrace deposits along streams, sand, silt, clay, and gravel.

Thickness variable. The unit appears on Geologic Map of Texas on the lagoon side of barrier islands where they represent lagoon and wind-tidal-flat sand and clay. These deposits of clay and silty, clayey fine to v. fine quartz sand and shell sand accumulate on alternately dry and flooded barren flats 0.3 m below to 1 m above mean sea level. Mapped areas include active eolian sand dunes on the landward side of barrier islands.

Deweyville Formation: sand, silt, clay, and gravel. locally indurated with calcium carbonate

(caliche); includes point bar, natural levee, stream channel, and locally, Recent and older sand dune deposits; surface shows relict meanders of much larger radius of curvature than those of present streams; thickness 50+ ft. Present at places along Guadalupe, Nueces, Jacinto, Trinity, Neches, and Sabine Rivers.

Project No. 23-787E 6

Terrace deposits: Sand, silt, clay, and gravel in various proportions, with gravel more predominant in older, higher terrace deposits. Locally indurated with calcium carbonate (caliche) in terraces along streams. Along Colorado River clasts mostly limest., chert, quartz, and various igneous and metamorphic rocks from Llano region and Edwards Plateau. Includes point bar, natural levee, stream channel deposits along valley walls, probably in large part correlatives of

Deweyville, Beaumont, Lissie, and Willis deposits. In upland regions (Rolling Plains, Edwards

Plateau, etc.) unit includes fluvial terrace deposits, undivided. Light-brown, reddish-brown, gray, or yellowish-brown, gravelly quartz and lithic sand and silt to sandy gravel (Moore and

Wermund, 1993). Deposits become increasingly fine grained on Coastal and Nueces Plains.

Locally, calcium carbonate-cemented quartz sand, silt, clay, and gravel intermixed and interbedded. The low terraces of major rivers are capped by 2-4 m of clayey sand and silt. Sandy gravel on higher terraces varies somewhat in composition from river to river. Gravel commonly is rounded to angular limestone and chert pebbles and cobbles, some boulders, sparse igneous pebbles along Brazos River in places. In Bastrop Co., a deposit 27 m above Colorado River contains the Lava Creek B (Pearlette O) volcanic ash (age 0.6 Ma). Along the Frio, Leona, and

Sabinal Rivers east of Uvalde, gravel is chiefly basalt and pyclastic clasts, locally cemented by iro oxide. Gravel along the Rio Grande is sub-rounded clasts of locally derived limestone and chert and rounded clasts of basalt, volcanic porphyry, quartzite, milky quartz, and banded chalcedony derived from the west.

3.3 Desktop Geologic Fault Study

Many faults have been observed within the Gulf Coast Region of Texas. In general, faults are caused by groundwater and oil removal from the underlying surface. Faults originate several thousand feet below the ground surface and can often cause displacement of the ground surface, causing broken pavement, ruptured utility lines, and damage to residential and commercial structures. The geologic fault maps of the area are presented on Plates 3 and 4.

Our review of the fault map (Ref. 3 and 4) indicates that there are no major active faults located along the project alignments. However, faults may be present that are absent from the published maps. The closest known fault to the project alignments is a Fault system located approximately

4.5-miles to the northeast of the project alignments. The other close fault is located approximately 7.5-miles to the northwest of the project alignments. No special study of movement rates for any of these faults was attempted. Therefore, it is our opinion that there is a relatively low risk of surface faulting along the project alignments.

4.0 FIELD EXPLORATION

4.1 Pavement Coring

The existing pavement was cored at each boring location prior to drilling and sampling. The results of pavement coring show that the existing pavements generally consist of asphalt and flexible base. The pavement component thicknesses at the borings are listed on Plate 8 and the boring logs in Appendix A. Pictures of the cores are presented in Appendix B of this report. The pavement core locations were grouted after the completion of the fieldwork.

Project No. 23-787E 7

4.2 Drilling and Sampling

The soil conditions were explored by conducting twenty-nine (29) borings (B-1 through B-29) along the project alignments. The plan of borings is presented on Plates 2 and A-1. The schedule of borings is as follows:

Notes 1 &2: The number of borings and depths were specified by the client.

Soil samples were obtained continuously at each boring location from the bottom of the pavement to the completion depth 10-ft below the existing subbase grade. The cohesive soils were sampled in general accordance with ASTM D 1587, using a Shelby Tube sampler.

Soil samples were examined and classified in the field, and cohesive soil strengths were estimated using a calibrated hand penetrometer. This data, together with a classification of the soils encountered and strata limits, is presented on the soil stratigraphy profiles on Plates 5 through 7. The logs of borings are presented on Plates A-2 through A-30 in Appendix A. A key to log terms and symbols is shown on Plate A-31 in Appendix A.

Depth to groundwater will be important for design and construction of the facilities. For this reason, borings were drilled dry, without the aid of drilling fluids, to more accurately estimate the depth to groundwater. Water level observations made during and after drilling are indicated at the bottom portion of the individual logs. The boreholes were grouted with non-shrink grout, using Tremie Method, after the completion of the field work.

Pictures of the project site were taken during our field explorations. These pictures are presented on cover page and Appendix B.

5.0 LABORATORY TESTING

5.1 General

Soil classifications and shear strengths were further evaluated by laboratory tests on representative samples of the major strata. The laboratory tests were performed in general accordance with ASTM Standards. Specifically, ASTM D 2487 is used for classification of soils for engineering purposes.

5.2 Classification Tests

As an aid to visual soil classifications, physical properties of the soils were evaluated by classification tests. The tests were conducted in general accordance with ASTM Standards.

These tests consisted of natural moisture content tests (ASTM D 4643), percent finer than the

No. 200 sieve tests (ASTM D 1140), Atterberg limit determinations (ASTM D 4318, Method A) and dry unit weights. Similarity of these properties is indicative of uniform strength and compressibility characteristics for soils of essentially the same geological origin. Results of these tests are tabulated on the boring logs at respective sample depths.

Facility Borings (1) Depth, ft (2)

Paving

B-1 through B-29

Project No. 23-787E 8

5.3 Particle Size Analysis Tests

This test was conducted in general accordance with ASTM D 422, the Standard Method for

Particle-Size Analysis of Soils. The soil sample was first separated into two portions using the

No. 10 (2.0-mm) sieve. A sieve analysis was performed on the soil samples retained on the No.

200 sieve. This test was performed on subbase samples obtained from Borings B-1, B-2, B-7, B-

10, B-13, B-16, B-19, B-22, B-25, and B-28. The analysis results are presented on Plates C-1 through C-10 in Appendix C.

5.4 Strength Tests

Undrained shear strengths of the cohesive soils, measured in the field, were verified by calibrated hand penetrometer tests, unconfined compressive strength tests (ASTM D 2166) and torvane tests. Natural water content and dry unit weight were determined routinely for each unconfined compressive strength test. These test results are also presented on the boring logs.

5.5 Soil Sample Storage

Soil samples tested or not tested in the laboratory will be stored for a period of three months subsequent to submittal of the final report. The samples will be discarded after this period, unless we are instructed otherwise.

6.0 SUBSURFACE SOIL AND GROUNDWATER CONDITIONS

6.1 Site Conditions

The project alignments exhibit a topographic variation of less than four-ft. Currently, the project alignments are covered with asphalt pavement, except for the Boring B-1 location, which was covered with fill soils. In general, the area along the project alignments consists of residential and commercial facilities. Project site alignment pictures were taken during our site visit. These pictures are presented on the cover page and in Appendix B. A field visit was conducted by Dr.

Mason Derakshandi, Project Manager at GET on October 19, 2023. During our field visit, we observed asphalt pavement cracking at multiple locations along the project alignments.

6.2 Soil Stratigraphy

Subsurface soils appear to be relatively variable across the site. Details of subsurface conditions at each boring location are presented on the boring logs. In general, the soils can be grouped into three (3) major strata with depth limits and characteristics as follows:

Project No. 23-787E 9

Stratum

No.

Range of

Depth, ft.

Soil Description*

– 0.15 – 0.92 ASPHALT PAVEMENT (1.75-inch to 11-inch in thickness)

– 0.15 – 1 FLEXIBLE BASE (1-inch to 8.5-inch in thickness)

I 0.42 – 2 SILTY SAND (SM), light brown to dark brown, brownish yellow, light gray to dark gray, with root fibers to 2’, ferrous nodules, gravels

II 0.42 – 1 SANDY SILT (ML), dark brown, dark gray, with root fibers to 1’

III 2 – 10 LEAN CLAY (CL), soft to very stiff, light brown to dark brown, reddish brown, brownish yellow, light gray to dark gray with root fibers to 10’, ferrous nodules, gravels, sand seals and layers

*Classification in accordance with the Unified Soil Classification System (ASTM D 2487)

6.3 Soil Properties

Based on results of soil laboratory testing, the engineering properties soils and how they relate to the pavement design along the project alignments are summarized below:

No. Soil Type PI(s)

Soil Expansivity

Soil Shear

Strength, tsf Remarks

I Sandy Silt (ML) – Non- Expansive – Moisture Sensitive

II Silty Sand (SM) – Non- Expansive – Moisture Sensitive

III Lean Clay (CL) 5 – 22 Non- to Moderately Expansive 0.15 – 1.50 –

Legend: PI = Plasticity Index

6.4 Water-Level Measurements

The soil borings were dry augered to evaluate the presence of perched or free-water conditions.

The levels where free water was encountered in the open boreholes during our field exploration and about 0.33 hours after drilling are shown on the boring logs. Our groundwater measurements are as follows:

Groundwater Depth, ft. Groundwater Depth, ft.

Boring No. at the Time of Drilling at 0.33 Hour Later

B-1 through B-29 Dry Dry

Fluctuations in groundwater generally occur as a function of seasonal moisture variation, temperature, groundwater withdrawal, water level and future construction activities that may alter the surface drainage and subdrainage characteristics of this site.

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An accurate evaluation of the hydrostatic water table in the relatively impermeable clays and low permeable silts/sands requires long term observation of monitoring wells and/or piezometers. It is not possible to accurately predict the pressure and/or level of groundwater that might occur based upon short-term site exploration. The installation of piezometers/monitoring wells was beyond the scope of our study. We recommend that the groundwater level be verified just before construction if any excavations such as construction of underground utilities, etc. are planned.

We recommend that GET be immediately notified if a noticeable change in groundwater occurs from that mentioned in our report. We would be pleased to evaluate the effect of any groundwater changes on our design and construction sections of this report.

7.0 PAVEMENT DESIGN

7.1 General

It is planned to improve existing asphalt pavement at Porter Lane, Alexander Lane, Duester Lane, Bobby Lane, Jerry Lane, and Louis Lane, Montgomery County, Texas. We understand that the planned improvements may include (a) replacing parts of existing two-lane asphalt roadways with new two-lane asphalt road, (b) milling the existing paving and replacing it with a new asphalt surface course and (c) conducting Full Depth Reclamation (FDR). The pavement design in this study is generally in accordance with AASHTO 1993 Guide of Design of Pavement

Structures (Ref. 2).

Furthermore, our site preparation and soil stabilization recommendations are generally developed on the basis of the Montgomery County Subdivision Rules and Regulations, dated July 2021

(Ref. 5).

7.2 Traffic Information

Based on the information provided by the client, two traffic loadings were used as follows:

Traffic Condition Estimated Traffic Loading

The roadway will be subjected to heavy construction equipment during the design life of 20-years.

10 x 106 ESALS

The roadway is subjected to a typical light resident traffic loading for a design life f 20-years.

Residential Pavement Design per

Montogomery County

Specifications for Asphalt Paving

7.3 Recommended Subgrade Design Values

Our reviews for laboratory test results indicate that subgrade soils are silty sand (SM) and sandy silt (ML) soils based on unified soils classification system (ASTM D 2487). The recommended design parameters for California Bearing Ratio (CBR) and Resilient Modulus (MR) values are 4 and 6,000 psi, respectively.

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7.4 Design Parameters and Pavement Recommendations

The following design parameters (based on ASSHTO 1993 Guide of Design of Pavement

Structure (Ref. 2) were used for the proposed pavement project.

AASHTO Design Parameter Design Value

ESAL × 106 for 20-year design life 10

Reliability, R 95%

Overall Standard Deviation, S0 0.45

Drainage Coefficient, mi 1.2

Design Serviceability Loss, Δ psi 2.0

California Bearing ratio (CBR) 4

Subgrade Resilient Modulus (MR) in psi 6,000

Structural Layer Coefficients

Hot-Mixed Hot-Laid Asphalt Surface Material 0.44

Crush Limestone Base 0.14

Black Base 0.34

Lime-Stabilized or Lime-Fly Ash Stabilized Earth 0.11

The recommended pavement component thicknesses during reconstruction are summarized as follows:

Based on the above design parameters, the recommendations for the minimum asphalt pavement section thickness are as follows:

Thickness, inch(es)

Crushed Limestone Base

Thickness, inch(es)

Subgrade Stabilization

10× 106 3.0 12.0 16.0

Our field and laboratory tests indicate that the surficial soils consist of silty sand (SM) and sandy silt (ML) soils. The subgrade preparation in pavement areas should specify compaction of the upper eight-inch to at least 95% of maximum standard Proctor density (ASTM D 698) at a moisture content between optimum and ±2 % of optimum moisture content.

Instead of crushed limestone base course, black base can also be considered along with Hot mix hot-laid asphaltic concrete with subgrade stabilization as shown below:

Thickness, inch(es)

Black Base Course

Thickness, inch(es)

Subgrade Stabilization

10× 106 2.0 8.0 10.0

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Per City of Conroe Design Manual, August 2008 (Ref. 1), the maximum lift thickness for black base and Hot mix hot-laid asphaltic concrete shall not be greater than 4-inch and 2-inch, respectively.

Detailed design computation is presented on Appendix D. Our design recommendations also consider good drainage is provided near the pavement structures, assuming the pavement are exposed to moisture levels approaching saturation from 1 to 5 percent of the time.

For the local streets with light traffic at Porter Heights Community, the recommended pavement thickness during reconstruction in accordance with Montgomery County Subdivision Rules and

Regulations are summarized below:

Crushed Limestone Base

Thickness, inch(es)

Subgrade Stabilization

2.0 8.0 6.0

This result in a structural number of 2.7 per AASHTO Pavement Design.

Black Base Course

Thickness, inch(es)

Subgrade Stabilization

Thickness, inch(es)

2.0 6.0 6.0

This result in a structural number of 3.6 per AASHTO Pavement Design.

7.5 Soil Stabilization

7.5.1 General

Our field and laboratory tests indicate that the surficial soils consist of silty sand (SM) and sandy silt (ML) soils. Our recommendations for subgrade stabilization for areas with cohesionless are provided in the following sections.

7.5.2 Subgrade Stabilization for Cohesionless

The subgrade preparation in pavement areas should specify compaction of the upper eight-inch to at least 95% of maximum standard Proctor density (ASTM D 698) at a moisture content between optimum and ±2% of optimum moisture content. The subgrade soils should be stabilized, using lime based on the Harris County Specification, Item No. 220 and 221. Use 2% lime and 8% fly-ash by dry weight to stabilize the subgrade soils. This results in application rates of about 12 pounds of lime and 48 pounds of fly-ash per square yard per 8-inch depth of compacted thickness. Harris County Specification Item 223 can be used as a procedural guide for placing, mixing, and compacting the lime stabilizer and the soils. The fly ash stabilization should be in accordance with Texas Department of Transportation (TxDOT) Specification, Item 265.

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In the event lime-fly ash is not available, cement can be used to stabilize the subgrade soils.

Subgrade preparation using cement stabilization in pavement areas should specify compaction of the upper eight-inch to at least 95% of maximum standard Proctor density (ASTM D 698) at a moisture content between ±2% of the optimum value. The ratio of cement to soil will be based on dry material weight and shall be established by the Geotechnical Engineer in the field to provide the desired stability. The ratio of cement to soil should be generally about 8% percent by dry weight. The subgrade should be treated in accordance with TxDOT Standard

Specification Item 275 for cement treatment.

Our recommendations on subgrade stabilization are preliminary. The actual depth and type of stabilization should be determined in the field at the time of construction just after site stripping and proofrolling. Furthermore, the type and amount of the stabilizer may vary depending on the final grade elevation and the soil type encountered.

7.6 Rehabilitation

7.6.1 Full-Depth Reclamation (FDR)

Full-Depth Reclamation (FDR) of asphalt pavement is a rehabilitation method that involves recycling an existing asphalt pavement and its underlying layer(s) into a new base layer. The

FDR process begins with using a road reclaimer to pulverize an existing asphalt pavement and a portion of the underlying base, subbase, and/or subgrade. Usually, the pulverized material is uniformly blended with an additional stabilizing material such as portland cement to provide an upgraded, homogeneous material. The result is a stiff, stabilized base that is ready for a new rigid or flexible surface course. Finally, the stabilized material is compacted in place with rollers. The result is a stiff, stabilized base that is ready for a new rigid or flexible surface course (Ref. 6).

The pulverized material blended with cement or lime is usually excess in quantity and hence the excess material after full-depth reclamation may be used for widening of paving or elsewhere for the construction of new paving.

To design flexible pavement, the structural layer coefficients of cement-treated FDR layers are suggested a reasonable value ranges from approximately 0.20 to 0.27 (Ref. 6).

Our recommendation for rehabilitation of the proposed pavement is FDR method because of the following benefits:

o Cost-effectiveness o Increased structural capacity o Increased durability (compared to granular base materials) o Opportunity to improve roadway geometry o Shortened construction schedule and improved staging o Early opening to traffic o Reduced impacts on the community during construction o Reduced carbon footprint

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Based on our experience with pavements consisting of inadequate pavement component thicknesses, a significantly reduced service life for the proposed pavement rehabilitation should be expected as compared to a newly constructed pavement section. In addition, increased levels of cracking and distress resulting in the need for more frequent maintenance should be expected for the repaired pavement.

If the existing pavement component changes to FDR, then Traffic Load Capacity, ESAL are summarized as follows:

Street Name

FDR

Traffic Load Capacity, ESAL

Porter Lane 7.5 50,000

Alexander Lane 8 50,000

Deuster Lane 6.5 50,000

Bobby Lane 8.5 50,000

Jerry Lane 5 40,000

Louis Lane 5 40,000

The recommended thicknesses of asphalt and black base layers over the FDR layer to support traffic load design with 10×106 ESAL are summarized as follows:

Thickness, inch(es)

Black Base Course

Thickness, inch(es)

(Over FDR)

FDR 1

Thickness, inch(es)

Porter Lane 2 6.5 7.5

Alexander Lane 2 6 8

Deuster Lane 2 7 6.5

Bobby Lane 2 6 8.5

Jerry Lane 2 8 5

Louis Lane 2 8 5

The recommended thicknesses of asphalt and black base layers over the FDR layer to support light traffic on local streets at Porter Heights Community, are summarized as follows:

Thickness, inch(es)

Black Base Course

Thickness, inch(es)

(Over FDR)

FDR1

Thickness, inch(es)

Porter Lane 2 3 7.5

Alexander Lane 2 3 8

Deuster Lane 2 4 6.5

Bobby Lane 2 2 8.5

Jerry Lane 2 5 5

Louis Lane 2 5 5

Note 1: Considering a structural layer coefficient of 0.23 and the existing pavement layers along each street as presented on Plate 8 of this report.

Addendum 2

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The proposed FDR sections may result in raising the existing pavement elevations. We recommend some of the FDR soils be removed to attain the design elevations. This may change the pavement section requirements.

7.6.2 Mill and Overlay

Mill and overlay is a common method used in pavement rehabilitation for asphalt roads. The existing asphalt surface layer needs to be milled completely down to the aggregate base, and a new HMAC layer of asphalt is replaced on top of the milled surface. According to the specifications of the City of Conroe Design Manual, August 2008, we recommend overlaying a minimum of 2 inches of new HMAC surface course on top of the pulverized existing pavement materials. After the milling process is completed, the surface should be proofrolled using a min.

25-ton pneumatic roller or similar machinery to identify any areas with low strength. The proofrolling process should be conducted under the observation of a geotechnical engineer.

Additionally, to prevent ponding of surface water, site drainage should be established in the project construction. The Mill and Overlay system can not carry the proposed traffic loading of

10× 106 ESAL.

8.0 ROADSIDE DITCHES

8.1 General

The proposed roadside ditch improvements along the project alignments will generally include existing ditches. The improvement to the existing ditch shall be conducted in accordance with

City of Conroe Design Manual, August 2008. The minimum grade on ditches shall be one percent (1%). Usual side slopes of ditches shall be 3:1. For major streets with speed limits over

50 mph, the slopes shall be 6:1, or as called for in the Texas Department of Transportation

Design Manual. The ditch shall be designed to handle runoff as determined in City of Conroe

Design Manual, August 2008, Division VI (Ref. 1).

8.2 Recommended Drainage Ditches Slope Ratio

The side slopes of ditches shall not be steeper than a ratio of 3:1. For major streets with speed limits over 50 mph, the slopes shall be 6:1, or as called for in the Texas Department of

Transportation Design Manual (Ref. 1).

8.3 Drainage Ditches Slope Erosion Protection

Erosion problems are usually associated with drainage ditch embankments. Excessive erosion can lead to a loss of ground and gradual (progressive) sloughing of the slopes. Consequently, progressive slope failures can occur. Dressing of the slopes with erosion control systems should ensure successful long-term performance. The erosion control systems may consist of grass cover.

We recommend grass cover over the slopes to provide a suitable erosion protection system provided the root systems can sustain the peak velocities from the rainwater. Periodic observation of slopes should be planned to identify areas that may require a more positive erosion protection system or maintenance.

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9.0 CONSTRUCTION CONSIDERATIONS

9.1 Surface Water Drainage

In order to minimize ponding of surface water, site drainage should be established early in the project construction so that this condition will be controlled.

9.2 Site Preparation

Project alignments have the potential for construction problems related to the surficial layer of cohesionless soils. These permeable surficial soils are underlain by relatively impermeable clay soils. Thus, due to poor site drainage, wet season or site geohydrology, water ponds on the clays soils and creates a “perched water table condition”. The surficial cohesionless soils could become extremely soft when wet, and must be stabilized, aerated, or replaced. In the event that these surficial soils become wet, they will experience rutting and pumping. Therefore, these soils may have to be improved. Our recommendations on subgrade improvements are presented in the earthwork section of this report. Our site preparation recommendations are presented below:

1. The requirement for removal of any existing paving, and subsoil materials will depend on final grades and other alignments information. In general, remove all vegetation, tree roots, organic topsoil, existing foundations, paved areas and any undesirable materials from the construction area. Tree trunks under the construction areas should be removed to a root size of less than 0.5-inch. We recommend that the stripping depth be evaluated at the time of construction by a soil technician.

2. Any on-site fill soils, encountered in the pavement areas during construction, must have records of successful compaction tests signed by a licensed professional engineer that confirms the use of the fill and record of construction and earthwork testing. These tests must have been performed on all the lifts for the entire thickness of the fill. In the event that no compaction test results are available, the fill soils must be removed, processed and recompacted in accordance with our site preparation recommendations. Excavation should extend at least two feet beyond the structure and pavement area. Alternatively, the existing fill soils should be tested comprehensively to evaluate the degree of compaction in the fill soils.

3. The subgrade areas should then be proofrolled with a loaded dump truck or similar pneumatic-tired equipment with loads ranging from 25- to 50-tons. The proofrolling serves to compact surficial soils and to detect any soft or loose zones. The proofrolling should be conducted in accordance with TxDOT Standard Specification Item 216. Any soils deflecting excessively under moving loads should be undercut to firm soils and recompacted. Any subgrade stabilization should be conducted after site proofrolling is completed and approved by the geotechnical engineer. The proofrolling operations should be observed by an experienced geotechnician.

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4. Scarify the subgrade, add moisture, or dry if necessary, and recompact to 95% of the maximum dry density as determined by ASTM D 698 (Standard Proctor). The moisture content at the time of compaction of subgrade soils should be between optimum and +3% of the Proctor optimum value. We recommend that the degree of compaction and moisture in the subgrade soils be verified by field density tests at the time of construction.

We recommend a minimum of four field density tests per lift or one every 2,500 square feet of floor slab areas, whichever is greater.

5. Structural fill beneath the pavement area may consist of off-site inorganic lean clays…