ADDENDUM NO. 1 RECEIPT DATE: July 28, 2016 @ … concrete abutments with wingwalls are proposed to support the pre-fabricated steel bridge. Erosion protection is proposed to protect

ADDENDUM NO. 1

DATE: July 20, 2016

INVITATION FOR BID: IFB K160021767 – Bellemeade Park Pedestrian Trails and Bridge Project

(UPC 107531)

DATED: June 28, 2016

RECEIPT DATE: July 28, 2016 @ 2:30 P.M.

OPENING DATE: July 29, 2016 @ 2:30 P.M. SUBJECT: Clarification/Question/Answer/Updated Plan Sheets

Ladies/Gentlemen:

Please take note of the following:

Clarification:

1. Project permits were discussed. The City has obtained an Army Corp of Engineers Nationwide

Permit 42 for the project. The City has obtained a building permit from the Building

Commissioner’s office for the bridge. This permit will be transferred to the contractor upon contract

award. The City has filed for a Richmond Stormwater Management Permit (RSMP). Upon contract

award, the contractor shall be added as the permitee and shall submit a responsible land disturber

form as required by the RSMP.

2. To clarify ‘maintenance of traffic’, is for the tie-in work at Minefee/Gunn Streets and maintaining

pedestrian access from Overlook Street. The work zone shall be maintained in a safe manner. Also,

note that areas of the park, especially the athletic field adjacent to the project area, may be in use for

school activities, after-school activities, and sports.

3. Revise the project special provisions paragraph F 3. (d) in the modifications to VDOT section 303 to

read ”All excess excavation shall be disposed of by the contractor. Costs for disposal shall be

incidental to type of excavation.

Questions/Answer:

1. Is there a soils report for this project? Answer: No

2. Is there a boring log and or report for this project? Answer: A boring report for the evaluation of the

bridge foundations was done. That boring report is attached. The borings are located as follows

based on the proposed trail baseline:

B-1 Station 15+79.83 Left 6.53 ft.

B-2 Station 15+46.30 Left 0.66 ft.

3. How are we to handle undercut and backfill of unsuitable material? Will there be a unit price per CY

that we need to fill in for this item? Answer: The items raised are to be paid for as Regular

Excavation in accordance with 303.06 of the VDOT specifications

4. How are we to handle undercut and backfill of rock? Will there be a unit price per CY that we need

to fill in for this item? Answer: The items raised are to be paid for as Regular Excavation in

accordance with 303.06 of the VDOT specifications

5. Are there lay down areas on site? Answer: No on-site lay down areas are delineated on the plans,

however, the contractor can coordinate short term storage of materials and equipment on site. The

Contractor shall be solely responsible for any material/equipment left on site.

6. Can access be made from the dirt road on the sports field side of the project? Answer: The alley

parallel to Royal Ave may be used for access. Contractor shall be responsible for restoring any

damage to the access that results from use.

7. What is Contractor’s responsibility for replanting trees? No payment is made in the contract.

Answer: Contractor shall be responsible for replanting the few small trees that are disturbed, but

the Contractor’s footprint in stream buffer strip shall remain narrow to minimize these impacts.

Contractor shall take due diligence to replant the trees but will not be held responsible for their

performance once the replanting has been accepted.

8. Will testing be required on the grounding of the rails? Will Contractor be responsible for the cost of

testing? Answer: Rails and handrails shall be grounded and tested in accordance with the

specifications and/or special provisions. Testing is the responsibility of the Contractor and cost shall

be incidental.

9. What is the required CBR of fill material? Answer: A minimum CBR value of 10 will be adequate

for fill material.

10. What is the grade tolerance for the trail? Answer: Trail shall be graded in accordance with the

specifications. This is a rock surface trail and final surface shall drain freely and be ADA compliant.

11. How will Borrow and Regular excavation be measured? Are they plan quantities? Answer: These

item shall be measured in cubic yards. The quantities are not Plan Quantities.

12. Will Contractor be held do liquidated damages if the fabricated bridge is late? Answer: The

project shall be substantially complete within the project duration. The Contractor should work with

their fabricator to ensure that the project is completed on-time.

13. Is a list of inspections provided? Answer: No. The required inspections are those required by the

various permits and in accordance with VTM.

14. Who will pay for concrete material testing? Answer: The Owner will provide acceptance testing at

expense of the Owner. The contractor shall provide quality control testing, at contractor expense,

prior to acceptance testing by the owner.

15. Is post installation pipe inspection included on this project? Answer: Yes – post inspection of

pipes is included in the scope of work. Post Installation Pipe Inspection is included in this project as

Item No. 23 in the Price Schedule; payment is made on a Lump Sum basis. Project incorporates the

2007 Virginia Department of Transportation Road and Bridge Specifications (with revisions).

Technical requirements for Post Installation Pipe Inspection are included in Supplemental

Specifications SS30204 dated 3-14-13, which can be found on VDOT’s website

http://www.virginiadot.org/business/resources/const/07RevDiv_III.pdf.

Revised Plan Sheets

4. Replace the original Plan Sheets 1, 2, 2E(1), 2F(1), 2F(2), 2F(3), 2F(4), 2F(5), 2(G) with the Revised

Plan Sheets 1, 2, 2E(1), 2F(1), 2F(2), 2F(3), 2F(4), 2F(5), 2(G).

Vendor must take due notice and be governed accordingly. This addendum must be acknowledged as indicated

in the Bid Book or your bid may not be considered.

Sincerely,

Kristina Jones

Kristina Jones, CPPO, VCO

Contract Specialist

804/646-5802

http://www.virginiadot.org/business/resources/const/07RevDiv_III.pdf

Sheet # Description of revision

1 Updated index of sheets; added revision #

2 Updated General Notes

2E(1) Added HGL to pipe profile for permit approval

2F(1)Revised ES&C plan. Added Limits of disturbance to plan.

Changes Temporary Filter barrier to silt fence.

2F(2) Clarified ES&C Notes to conform to City standards

2F(3) Revised Soils Map to add erodibility notes

2F(4)Clarified ES&C Notes. Added project specific suggested

sequence of construction.

2F(5) Revised and Clarified seeding schedule

2(G)Deleted SWPPP and revised sheet to BMP compliance for

RSMP

Bellemeade Park Plan revision summary

Drawing # O‐28594

Mark S Vasco2016.07.08 15:56:18 -04'00'

David S Gertz2016.07.08 11:39:51 -04'00'

David S Gertz2016.07.08 11:37:47 -04'00'

David S Gertz2016.07.08 11:38:21 -04'00'

David S Gertz2016.07.08 11:38:58 -04'00'

City of Richmond, Virginia Proposed Bellemeade Park Pedestrian Bridge over Goode Creek

1

Table of Contents 1. Introduction .......................................................................................................................................... 2

2. Subsurface Exploration Program .......................................................................................................... 2

3. Subsurface Conditions .......................................................................................................................... 2

4. Groundwater ......................................................................................................................................... 3

5. Design Soil Parameters ......................................................................................................................... 3

6. Analysis and Recommendations ........................................................................................................... 3

6.1. Abutment & Wingwalls ................................................................................................................. 4

6.2. Earthwork Recommendations ...................................................................................................... 4

7. References ............................................................................................................................................ 4

List of Tables Table 1: Summary of SPT Boring Depths 1 Table 2: Summary of Groundwater Depths 4 Table 3: Summary of Soil Parameters 5 Appendices: Froehling & Robertson Summary of Drilling Testing Services


2 V:\45820-016\Engineering\Design\Geotech\Geotechnical Report Bellemede Bridge.docx

1. Introduction

The Proposed Bellemeade Park Pedestrian Bridge over Goode Creek is to be part of Virginia’s Safe Routes to School Program. It will carry the six (6) feet wide pedestrian trail over Goode Creek for a span of 29 feet. Two concrete abutments with wingwalls are proposed to support the pre-fabricated steel bridge. Erosion protection is proposed to protect the abutments from scour.

2. Subsurface Exploration Program

A subsurface investigation was conducted on March 14, 2014 to ascertain the subsurface conditions at the project site. Froehling and Robertson drilled and sampled two (2) soil borings.

The borings were drilled using 6-inch diameter hollow stem augers. Samples were taken and standard penetration tests were performed using a 2-inch O.D. split spoon sampler driven by a 140-pound hammer falling freely for 30 inches, in accordance with ASTM D1586. Blow counts were recorded for each 6-inch increment for a total penetration of 18 inches. The following table provides a summary of the drilled boring depths.

Table 1: Summary of SPT Boring Depths

Boring Designation Drilled Boring Depth (feet)

Auger Refusal Elevation

B-1 12.1 EL 42

B-2 13.6 EL 39

Note: Borings were terminated upon reaching auger refusal.

3. Subsurface Conditions

Both borings were drilled through 5 inches of existing topsoil. The following sections provide a description of each strata encountered from shallowest to deepest.

Alluvium A (EL 53.6 to EL 46.5): Moist to wet, loose to medium dense Silty SAND and firm Sandy CLAY. Standard Penetration Testing (SPT) blow counts ranged from 6 to 28 blows per foot (bpf). Residuum R (EL 46.5 to 42.5): Moist to wet, medium dense Silty fine to medium SAND. SPT blow counts ranged from 13 to 21 bpf.



Weathered Rock WR (EL 42.5 to bottom of borings): Weathered rock is defined as residual soils having a blow count of 100 bpf or more. Samples within this stratum consisted of wet, brown and dark gray, Silty fine to coarse SAND with trace mica and rock fragments. Auger refusal was reached in both borings as noted in the table above.

4. Groundwater

The depth that groundwater was encountered in each boring was recorded on the boring logs. The following table provides a summary of the depths that groundwater was encountered during drilling and after completion of the borings:

Table 2: Summary of Groundwater Depths

Boring Designation Encountered Depth (feet)

Depth at Completion (feet)

B-1 6.0 6.0

B-2 6.0 -

The localized groundwater table likely corresponds to the stream elevation which is at EL 50 in the vicinity of the bridge.

5. Design Soil Parameters

Design soil parameters were generally developed using uncorrected blow counts based on the empirical relationship between blow counts and the angle of internal friction as well as the unit weight of granular soils after Bowles, 1996. For cohesive soils, parameters were developed using the empirical relationship between uncorrected blow counts and cohesion, as well as the unit weight.

Table 3: Summary of Soil Parameters Stratum Unit Weight,

γ (pcf)

Angle of Internal Friction

(degrees)

Cohesion (psf)

Alluvium (A) 110 30 0 Residual (R) 120 32 0

Weathered Rock (WR) 130 34 0

6. Analysis and Recommendations

The following sections provide a summary of the analyses and recommendations for the proposed pedestrian bridge abutment, wingwalls and slope protection.



6.1. Abutment & Wingwalls

WRA’s civil engineers calculated a worst case bearing pressure of 3000 pounds per square foot (psf) and an abutment size of seven (7) feet wide and ten (10) feet long. Bearing capacity was considered using LRFD design to apply factors to each soil resistance. Bearing Resistance increases as the stratum changes from Alluvium to Residuum. The minimum required footing embedment is 1.0 foot into Stratum R at approximately EL 47 to provide a strength case factored bearing resistance of 3000 psf. Founding the footing at EL 47 ensures at least 2.5 feet of coverage against frost penetration. Scour is not considered as the stream bed is to be covered in 26 inches of Class 1 rip rap as a countermeasure. Settlement was considered using LRFD design and the elastic half space method. A negligible amount of settlement was calculated to occur for the proposed abutments. The foundation subgrade should be inspected by competent Geotechnical personnel to ensure the bearing material is consistent with that described herein and identified in the soil borings. All soft areas encountered should be excavated and replaced with 21B or similar crushed aggregate.. Dewatering through sumps and perimeter troughs berms and coffer dam configurations is expected to be required during foundation construction. The contractor should be responsible for the design of the dewatering system.

6.2. Earthwork Recommendations

Excavation will be required to reach the bearing stratum for the footings. Soils have a sufficient internal angle of friction to be open cut and sloped back. It may be preferable to use support of excavation (SOE) for footing excavation.

Groundwater was observed at EL 48 and EL 47. The stream elevation is EL 50. Dewatering during excavation to bottom of footing at EL 47 is to be expected to be required.

7. References

AASHTO (2012), “LRFD Bridge Design Specifications, 6th Edition,” Association of State Highway and Transportation Officials Publication, Washington, D.C. ISBN: 978-1-56051-555-5.

Documents

ADDENDUM NO. 1 RECEIPT DATE: July 28, 2016 @ … concrete abutments with wingwalls are proposed to support the pre-fabricated steel bridge. Erosion protection is proposed to protect