3-Attachment B.pdf

IFB 2000004140

Attachment B

TECHNICAL SPECIFICATIONS

Work performed under this contract shall include repair, replace and installation of new concrete surfaces including, but not limited to sidewalks, curbs, gutters, steps, ramps, curb cuts, footings retaining walls and miscellaneous concrete related work in accordance with the specifications shown below.

PRE-INSTALLATION: Concrete shall be placed on a properly prepared sub-grade with 4 inches of compacted 21A base stone. Where existing 21-A sub-base is utilized, there will be a 15% reduction to the cost of the pour for that area.

Unit quantities shall be cumulative per job address unless waived in writing by the applicable department.

1. CONCRETE MATERIALS:

1.1. Provide concrete to the following criteria:

a. Compressive Strength - 28 days, minimum 3,000 psi

b. Slump - 1 to 5 inches

c. Air Content (%): 6 ± 2

1.2. Concrete Mix

a. Non-exposed aggregate - VDOT Class A-3 (General Use Concrete)

b. Exposed aggregate - approved VDOT concrete mix design meeting ADA requirements

c. Water Repellent: Exposed aggregate to receive one application of CHEM-TRETE

BSM 40 VOC, or equal.

1.3. Admixtures - as approved by the Project Manager

a. Use accelerating admixtures in cold weather, only when approved by the

Project Manager. Use of admixtures will not relax cold weather placement requirements.

b. Use set retarding admixtures during hot weather only when approved by the Project Manager.

1.4. Use calcium chloride only when approved by the Project Manager.

2. HELICAL ANCHOR MATERIAL:

2.1. Central Steel Shaft - The central steel shaft, consisting of lead sections, helical extensions, and plain extensions, shall be Square shaft(Square Shaft Type SS5, SS150, SS175, SS200, and SS225) or RS (Round Shaft Type RS2875, RS3500, and RS4500) or a combination of the two (SS to RS Combo Pile Type SS to RS2875, SS to RS3500 and SS to RS4500) as manufactured by CHANCE Civil Construction (Centralia and Independence, MO) or equivalent.

2.2. Helix Bearing Plate shall be hot rolled carbon steel sheet, strip, or plate formed on matching metal dies to true helical shape and uniform pitch

2.3. Couplings For type SS5, SS150, SS175, SS200, and SS225 material, the coupling shall be formed as an integral part of the plain and helical extension material as hot upset forged sockets. For Type SS125 and SS1375 material, the coupling shall be a cast steel sleeve with two holes for connecting shaft sections together. For Type RS2875, RS3500, and RS4500 material, the couplings shall either be formed as an integral part of the plain and helical extension material as hot forge expanded sockets, or as internal sleeve wrought steel connectors. The steel connectors can be either tubing or solid steel bar with holes for connecting shaft sections together.

3. ACCESSORIES, JOINT DEVICES & FILLER MATERIAL:

3.1. Vapor barrier - clear polyethylene film, 6 ml, below grade application.

3.2. Joint filler - asphalt impregnated fiberboard or felt, ½ inch thick, ASTM D1751 or ASTM D994.

3.3. Sealant and Primer - as directed by the Project Manager

4. WORKMANSHIP:

4.1. All work shall be performed in accordance with American Concrete Institute (ACI) 301. Work performed which does not conform to the required lines, details, dimensions, tolerances or specifications included in this contract will be determined defective and will be required to be removed and replaced at no additional cost to the County.

4.2. Helical Piles shall be installed by authorized helical pile manufacturer certified Contractor.

These Contractors shall have satisfied the certification requirements relative to the technical aspects of the product and installation procedures as therein specified. Certification documents shall be provided upon request to the Owner or their representative.

5. EXAMINATION:

5.1. Contractor must verify work site conditions.

5.2. Contractor must verify the requirements for concrete cover over any reinforcements.

5.3. Contractor must verify that anchors, seats, plates, reinforcements and other items to be cast into the concrete are accurately placed, positioned securely, and will not cause hardship in placing concrete.

6. PROJECT RECORDS:

6.1. Contractor shall accurately record actual locations of embedded utilities and components which are concealed from view. Note: It is the Contractor’s responsibility to notify “Miss Utility” 48 hours prior to digging.

6.2. Contractor shall call in a private utility locating company when deemed necessary by the Project Manager to locate County owned utilities in affected work area. The private utility locating contractor will be billed as a subcontractor to the County with all terms of a subcontractor being met such as: pre-approval of the subcontractor’s price prior to work and a copy of the subcontractor’s invoice to accompany the contractor’s invoice as backup documentation.

7. PREPARATION:

7.1. Coordinate the placement of joint devices with the erection of concrete form work and the placement of the form accessories.

7.2. Prepare previously placed concrete by cleaning with a steel brush and applying a bonding agent in accordance with the manufacturer’s instructions.

7.3. In locations where new concrete is doweled to existing work, drill holes in existing concrete, insert steel dowels and pack solid with non-shrink grout.

8. PLACING OF CONCRETE:

8.1. Notify the Project Manager a minimum of 5 business days prior to commencement of operations.

8.2. Before the concrete is placed:

a. Subgrade shall be graded level and compacted with a pneumatic hand tamper.

b. A four (4) inch layer of base stone (VDOT- type 21 A) shall be placed and compacted with a pneumatic hand tamper.

8.3. When unsuitable material is present, the Contractor shall notify the Project Manager before proceeding. Any additional removal (undercutting) of material will be paid as outlined in the Pricing Schedule.

8.4. Ensure that reinforcements, inserts, embedded parts, formed joint fillers and joint devices are not disturbed during concrete placement.

8.5. Repair vapor barrier damaged during placement of concrete reinforcing. Lap over damaged areas a minimum of 6 inches and seal watertight.

8.6. Install joint devices, fillers, primers and sealants in accordance with the manufacturer’s instructions.

8.7. Separate slabs on grade from vertical surfaces with ½ inch thick joint filler.

8.8. Extend joint filler from bottom of slab to within ¼ inch of finished slab surface.

8.9. Maintain records of concrete placement. Record date, location, quantity, air temperature, and test samples taken.

8.10. Place concrete continuously between predetermined expansion, control and construction joints.

8.11. Do not interrupt successive placement; do not permit cold joints to occur.

8.12. Saw cut joints where required and 24 hours after placing. Using a 3/16 inch blade, cut joint to ¼ inch depth.

8.13. Screen floors and slabs on grade level maintaining a maximum ¼ inch in 1 foot cross slope.

8.14. Steel trowel and broom finish surfaces

9. PLACEMENT OF HELICAL ANCHORS:

9.1. Central Steel Shaft: (Lead and Extension Sections)

a. The Helical Pile installation technique shall be such that it is consistent with the geotechnical, logistical, environmental, and load carrying conditions of the project.

b. The lead section shall be positioned at the location as shown on the working drawings.

Battered Helical Piles can be positioned perpendicular to the ground to assist in initial advancement into the soil before the required batter angle shall be established. The Helical Pile sections shall be engaged and advanced into the soil in a smooth, continuous manner at a rate of rotation of 5 to 20 RPM’s. Extension sections shall be provided to obtain the required minimum overall length and installation torque as shown on the working drawings. Connect sections together using coupling bolt(s) and nut torqued to 40 ft-lb.

c. Sufficient down pressure shall be applied to uniformly advance the Helical Pile sections approximately 3 inches per revolution. The rate of rotation and magnitude of down pressure shall be adjusted for different soil conditions and depths.

d. Termination Criteria - The torque as measured during the installation shall not exceed the torsional strength rating of the central steel shaft. The minimum installation torque and minimum overall length criteria as shown on the working drawings shall be satisfied prior to terminating the Helical Pile installation.

If the torsional strength rating of the central steel shaft and/or installation equipment has been reached prior to achieving the minimum overall length required, the Contractor shall have the following options:

i. Terminate the installation at the depth obtained subject to the review and acceptance of the Owner, or:

ii. Remove the existing Helical Pile and install a new one with fewer and/or smaller diameter helix plates. The new helix configuration shall be subject to review and acceptance of the Owner. If re-installing in the same location, the top-most helix of the new Helical Pile shall be terminated at least (3) three feet beyond the terminating depth of the original Helical Pile.

iii. It is generally not recommended to re-use Square shaft Helical Pile shaft material after it has been permanently twisted during a previous installation.

Likewise, it is generally not recommended to re-use Type RS Helical Pile shaft material after the coupling bolt holes have been noticeably elongated during a previous installation.

iv. The average torque for the last three feet of penetration shall be used as the basis of comparison with the minimum installation torque as shown on the working drawings. The average torque shall be defined as the average of the last three readings recorded at one-foot intervals.

10. CURING:

10.1. Immediately after placement, protect concrete from premature drying, excessive hot or cold temperatures, and mechanical damage. Method of curing to be coordinated with the Project Manager.

10.2. Maintain the concrete with minimal moisture loss at a relatively constant temperature for a period necessary for proper hydration of cement and hardening of concrete.

10.3. Proper protection must be taken when temperatures will dip below freezing during the curing process such as but not limited to blankets, polyethylene and straw.

10.4. Curing compounds shall be used on all concrete pours with the exception of curbs that are slated to be painted such as curbs in fire lanes.

11. PROTECTION:

11.1. The Contractor shall take the necessary precautions and shall provide any necessary notification to prevent damage to property caused by execution of this contract.

11.2. The Contractor shall protect the public from any damage due to his operations. Excavated concrete, stone or dust shall be removed as work progresses.

11.3. The Contractor shall provide all necessary barriers, guards, etc. to protect pedestrians from work areas.

12. REMOVAL OF FORMS & PATCHING:

12.1. Form removal shall be in accordance with the current VDOT Road and Bridge Specifications, or as directed by the Project Manager.

12.2. Allow Project Manager to inspect concrete surfaces immediately upon removal of forms.

12.3. Excessive honeycomb or embedded debris in concrete is not acceptable. Notify the Project

Manager upon discovery.

12.4. After the concrete has set sufficiently, all edges around the concrete, sidewalks, curb & gutter, ramping, etc., shall be backfilled, or as directed by the Project Manager.

12.5. Contractor is not to patch, fill, touch-up, repair or replace exposed concrete except upon written direction from the Project Manager.

13. SITE CLEANUP AND RESTORATION:

13.1. All waste and foreign materials shall be removed and properly disposed of by the Contractor.

The entire work area is to be left in a neat and presentable condition.

13.2. Where asphalt has been removed for construction, the Contractor shall be responsible to make repairs using an approved “hot mix” asphalt or as directed by the Project Manager.

13.3. All areas requiring backfill are to be fully compacted and graded to facilitate runoff of storm water. Seed or sod is to be applied to all excavated areas at the direction of the Project Manager. The method of payment for areas requiring unusual access, grading and equipment requirements is indicated in the Pricing Schedule.