BID 2025-29 Addendum 2.pdf

INVITATION TO BID #2025-29

Three Creeks Floodplain Enhancement Project

ADDENDUM NUMBER 2

April 24, 2025

On March 27, 2025, Clackamas County (“County”) published Invitation to Bid #2025-29 (“BID”) and Addendum #1 on April 22, 2025. The County has found that it is in its interest to amend the BID through the issuance of this Addendum #2. Except as expressly amended below, all other terms and conditions of the original BID and subsequent Addenda shall remain unchanged.

SECTION 00245 - TEMPORARY WATER MANAGEMENT

Construction

00245.40 Fish Removal - The Contractor will remove fish and other aquatic organisms from the isolation Work areas. Coordinate fish removal with the Engineer at least 28 Calendar Days before beginning Work in regulated Work areas. Allow access into the isolation Work areas before, during and after installation of the TWMF to perform the specified tasks as follows.

SECTION 00282 - HIGH VISIBILITY SEDIMENT FENCE

Section 00282, which is not a Standard Specification, is included in this Project by Special Provision.

Description

00282.00 Scope - This work shall consist of obtaining, installing, maintaining, and removing High Visibility Sediment Fence as described in the Contract Documents.

00282.01 Related Sections

A. All Contract Documents.

B. Contract, Addenda and Approved Change Orders, Specifications, Approved Submittals, Plans and Reference Standards shall govern in this order.

C. Section 00280 Erosion and Sediment Control.

00282.02 Abbreviations, Definitions, and Terms - See contract documents:

A. HVSF - High Visibility Sediment Fence.

B. ASTM - American Society for Testing Materials.

00282.03 Submittals - The Contractor shall submit the following supplier information and material data to the Owner for approval for the following features/structures:

A. The Contractor shall submit the source of supply and material data for all the high visibility sediment fence and components listed in the Contract Documents including geotextile, posts, and fasteners. After fencing removal, all seed placed for disturbed ground stabilization shall be submitted and approved under other applicable seeding line items.

00282.04 Quality Assurance - Contractor shall ensure the material delivered to the site matches and is consistent with the approved material submittals for High Visibility Sediment Fence. Any substitutions or material alterations proposed for use must be submitted and approved before application.

00282.05 Delivery, Storage, and Handling - Store High Visibility Sediment Fence in approved staging and stockpile areas.

00282.06 Sequencing and Scheduling - High Visibility Sediment Fence shall be installed prior to any land disturbing activities as indicated on the approved Plans or as directed and/or approved by the Owner.

00282.07 Warranty - The Contractor shall warranty the High Visibility Sediment Fence for the contracted length of time. Any material that must be replaced or repaired shall be replaced or repaired by the Contractor at no additional cost to the Owner.

00282.08 Maintenance - The Contractor shall maintain the High Visibility Sediment Fence for the contracted length. When water and sediment deposits reach approximately ⅓ the height of the HVSF, or 8 inches whichever is lower, the deposits shall be removed and the soil stabilized in accordance with Section 00280.63 Sediment Removal.

Materials

00282.10 General:

A. Contractor shall only use products which have been approved by the Owner and/or Engineer.

B. It is best practice to provide approved like materials from the same manufacturer or supplier to provide consistent composition and appearance. When more than one manufacturer or supplier is necessary to obtain the materials in the quantities and/or timeframe necessary, the Contractor shall provide a submittal for each different manufacturer or supplier and receive approval from the Owner prior to application.

00282.11 Materials:

A. High Visibility Sediment Fence:

1. High visibility sediment fence shall be a minimum of 5 feet in height, high visibility orange in color, and only be used for the dual purpose of demarcating site preservation lines and a sediment control device in a location where high visibility mesh fence and black silt fence would otherwise be used together at same location. The HVSF geotextile material shall be UV stabilized and meet the material requirements of Table 1.

2.

Mass/Unit Area 700 grams/sq. meter Thickness At least 0.35 inches Shear Stress 4.5 psf Velocity 12.0 ft/sec Open Area – Calculated 50% UV Stability 80% min. @500 hrs

3. Any substitutions must be approved by the Owner.

B. Posts:

1. Posts shall be either wood or steel, 1¼ by 1¼ inches by the minimum length shown in the accompanying detail, and shall be free of defects such as knots, splits, or gouges.

2. The posts shall have sufficient strength and durability to support the fence through the life of the project.

3. Backup support is needed for high visibility sediment fence in areas where extra strength may be required, such as the toe of steep cut or fill slopes or areas where equipment may push excessive soils toward the sensitive or protected areas. When backup support is used, wire shall have a maximum mesh spacing of 2 inches, and the plastic mesh shall be as resistant to ultraviolet radiation as the geotextile it supports.

The strength of the wire or plastic mesh shall be equivalent to or greater than as required in Table 1, for unsupported geotextile (i.e., 180 lbs. grab tensile strength in the machine direction).

4. Post spacing shall be as shown in the accompanying detail.

5. Any substitutions must be approved by the Owner.

C. Soil material shall be excavated for High Visibility Sediment Fence structures as needed, stockpiled, re-used if considered suitable or hauled offsite and disposed. All excavation necessary to install High Visibility Sediment Fence shall not be paid but is considered incidental to structures.

Table 00282-1

Geotextile Property

ASTM

Test Method

Geotextile Property Requirements 1

Unsupported Between Posts

Supported Between Posts With Wire or

Polymeric Mesh AOS D4751 No. 30 max. for slit wovens, No. 50 for all other geotextile types, No. 100 min.

Water Permittivity D4491 0.02 sec-1 min.

Grab Tensile Strength, in machine and x-machine

D4632 180 lb min. in machine direction, 100 lb min. in x-machine direction

100 lb min.

Grab Failure Strain, in machine and x-machine direction

D4632 30% max. at 180 lb or more

Ultraviolet (UV) Radiation Stability

D4355 70% strength retained min., after 500 hours in xenon arc device

1 All geotextile properties in Tables 1 are minimum average roll values (i.e., the test results for any sampled roll in a lot shall meet or exceed the values shown in the table).

00282.12 Equipment - It is the responsibility of The Contractor to utilize the appropriate equipment necessary to complete the requirements in this specification in a safe working manner.

Construction

00282.40 General:

A. The Contractor shall install the High Visibility Sediment Fence in accordance with the Contract Documents.

B. The Contractor shall utilize all materials, tools, equipment, and labor to perform this scope of work to the standards set forth in the Contract Documents.

00282.41 Preparation - Prepare for the placement of the High Visibility Sediment Fence by excavating a trench per the accompanying detail.

00282.41 Installation:

A. High Visibility Sediment Fence shall be placed by mechanical or other acceptable methods as shown per the construction details on the Plans or as directed by the Owner.

B. Fencing shall be securely attached to the posts and support system in accordance with manufacturer’s guidelines and in a manner that reduces the potential for tearing. Post spacing and attachments shall be as shown in the accompanying detail.

C. HVSF shall be no less than 48 inches above ground level and a minimum of 4 inches of fabric shall be trenched below ground level to prevent water and sediment from bypassing beneath the fencing.

00282.42 Closeout Activities - The Contractor shall be responsible for the removal of all trash and any other materials incidental to the project and disposing of them off-site at no additional cost to the Owner. The Contractor shall restore add disturbed areas in accordance with Section

00280.63 Sediment Removal.

Measurement

00282.80 Measurement - High visibility sediment fence will be measured by the linear foot along the ground line of the completed fence.

Payment

00282.90 Payment - The accepted quantities of Work performed under this Section will be paid for at the Contract unit price, per linear foot for the Bid item "High Visibility Sediment Fence".

The unit contract price per linear foot for "High Visibility Sediment Fence" shall be full pay for all costs to obtain, install, maintain, and remove the fence as specified. Once removed, the fencing shall remain the property of the Contractor.

Detail

NOTES

1. Angle Terminal end uphill 24" (in) to 48" (in) to prevent flow around fence (Typical).

2. Perform maintenance in accordance with specification.

3. Splices shall never be placed in low spots or sump locations. If splices are located in low or sump areas, the fence may need to be reinstalled unless the Project Engineer approves the installation.

4. Install silt fencing parallel to mapped contour lines.

End of Addendum 2