B.08_Amendment 04 - 01 11 00.00 25_Revised.pdf

Coos Bay North Jetty Repair

SECTION TABLE OF CONTENTS

DIVISION 01 - GENERAL REQUIREMENTS

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SUMMARY OF WORK

PART 1 GENERAL

1.1 SUMMARY

1.2 WORK COVERED BY CONTRACT DOCUMENTS

1.2.1 Background

1.2.2 Project Description

1.2.3 Location

1.3 CONTRACT DRAWINGS

1.4 EXISTING WORK

PART 2 PRODUCTS - NOT USED

PART 3 EXECUTION - NOT USED

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SUMMARY OF WORK

PART 1 GENERAL

1.1 SUMMARY

This Section provides a summary of the various Contract work elements and their relationship to each other. This summary describes work activities within interim construction completion dates. This Section does not provide the technical detail for particular work activities, but describes the work as a whole, providing overall perspective to the separate tasks and their interrelationships. Use this Section in conjunction with all the Specification Sections and the Drawings to establish the total work requirements.

1.2 WORK COVERED BY CONTRACT DOCUMENTS

1.2.1 Background

The Coos Bay North Jetty is located on the southern end of the Coos Bay North Spit on the south-central Oregon coast near Charleston, Coos County, Oregon. The North Jetty is a rubble-mound jetty approximately 8,800 feet long that was completed to its full length in 1931. It has lost approximately 370 feet from its last repaired head station of 86+40, and the deteriorated jetty head has been de-stabilized. In addition, reaches of the trunk and root of the North Jetty have either degraded over time or have been shown to be more vulnerable to damage due to the lower crest elevation. The Log Spiral Bay, which is located just north of the North Jetty root, has been shown to be more exposed to erosion due to jetty root degradation.

1.2.2 Project Description

The project includes the work described below and incidental related work.

This effort is to include all associated works required and described within this Contract package.

a. The repair template for this jetty repair work has a 20-foot to 40-foot crest width, 1V:1.5H to 1V:2.5H side slopes, and a crest elevation ranging from +15.5 to +24.5 feet NAVD88, as shown in the drawings and described in the specifications. As work progresses seaward, the crest elevation changes from +15.5 feet NAVD88 to +19.5 feet NAVD88 to +24.5 feet NAVD88. The crest width changes from 20 feet to 30 feet at the jetty root and again from 30 feet to 40 feet at the jetty head. The side slopes change from 1V:1.5H to 1V:2.5H as the work proceeds seaward along the jetty length. The jetty head includes a toe berm with a crest width and a height of 14 feet, with side slopes of 1V:2.0H. The crest elevation of the toe berm varies with the relic stone base elevation. A jetty access ramp may be located on the north side of the jetty adjacent to the north jetty staging area and above Mean Higher High Water (MHHW) elevation. A temporary material offloading facility (MOF) may be constructed in the area north of Log Spiral Bay on the east shoreline of the North Spit as shown on the drawings or as approved by the CO.

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b. The repairs consist of procurement and delivery of stones and placement of stones along the identified repair areas. Some haul road improvements, including grading, turnouts, and placement of stone are anticipated to gain access to the jetty repair areas.

c. Staging areas have been identified on the drawings.

d. Maximum depth of construction is estimated at about elevation -18 feet NAVD88 at the jetty head, but depths may vary. Some reworking of the existing jetty base and root stone is anticipated prior to placement of new stone. Repair work includes removal of existing inferior quality jetty stone and replacement with new jetty stone meeting size and quality specifications. Reconstruction of relict stone in areas that do not require new stone to fill the design template will also be required.

e. Access to the jetty work area must be closed to the public during construction.

f. The drawings are based on a bathymetry survey conducted using multi-beam survey methods between 5-6 June 2019 and topography, photogrammetrically derived aerial photography, taken 19 May 2019. It is anticipated that the jetty will continue to erode and change with time. Therefore, the jetty will likely differ at the time of construction from that shown on the drawings, particularly at the jetty head.

g. The jetty stone estimated quantities listed in the solicitation and in the measurement and payment section are based on the same 2019 survey data that was used for the drawings. The estimated quantities listed for the stone classification CLINs were calculated based on the volume needed to fill the construction template between the template neatline and the existing surface from the 2019 surveys; in addition, the amount of additional degradation that would occur over the course of project construction was estimated based on historic data and estimated construction year of each section of jetty. The estimated template neatline volume and estimated degradation were added together to determine the total estimated volume. The total estimated volume was multiplied by 0.7 to account for an average of 30% void space to determine the total estimated volume of jetty stone needed to fill the template to the neatline. It is anticipated that the jetty will continue to erode and change with time. Therefore, a new survey must be completed immediately prior to construction. The estimated quantities must be re-calculated by replacing the 2019 survey with the new survey data.

h. The anticipated construction schedule is no more than two construction seasons following the contract Notice to Proceed.

1.2.3 Location

The Coos Bay North Jetty is located in Coos County at the southern end of Coos Bay North Spit near the town of Charleston.

1.3 CONTRACT DRAWINGS

a. The Drawings that accompany these Specifications are a part thereof.

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b. Contract drawings, maps, and Specifications will be furnished to the Contractor without charge per Section 00 72 00 Contract Clause 252.236-7001, CONTRACT DRAWINGS AND SPECIFICATIONS. Reference publications will not be furnished.

c. Immediately check furnished drawings, maps, and specifications and notify the Government of any discrepancies.

1.4 EXISTING WORK

In addition to Section 00 72 00 Contract Clause 52.236-9, PROTECTION OF

EXISTING VEGETATION, STRUCTURES, EQUIPMENT, UTILITIES, AND IMPROVEMENTS:

a. Remove or alter existing work in such a manner as to prevent injury or damage to any portion of the existing work to remain.

b. Upon completion of the work, repair or replace portions of existing work, which have been damaged by Contractor's operations, to preconstruction conditions at the expense of the Contractor.

PART 2 PRODUCTS - NOT USED

PART 3 EXECUTION - NOT USED

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