Attachment 2 - Technical Specifications for Base Camp.pdf

TECHNICAL SPECIFICATIONS

E-00419 – SIERPE MOBILE CAMP

International Narcotics and Law Enforcement Affairs

March 2019 ii

C1. Content

C1. GENERAL DESCRIPTION

C2. SPECIFIC TASK

C2.1 Preliminary work

C2.2 Existing road improvement and access construction

C2.3 Camp slab and boat ramp construction

C2.4 Drinking water systems

C2.5 Wastewater system

C2.6 Electrical system

C2.7 Provision and Installation of Containers

C3. GENERAL SPECIFICATIONS

C3.1 Quantities

C3.2 Trials and Tests

C3.3 Work Execution

C3.4 Cost of the Project

C4. TASK SPECIFICATIONS

C4.1 Preliminary Work

C4.1.1 Demolition and land clearing

C4.1.2 Leveling and plotting

C4.1.3 Warning Signs

C4.1.4 Temporary Structures

C4.2 Earthwork, Excavation and Backfilling

C4.2.1 Leveling and land clearing

C4.2.2 Excavation

C4.2.3 Over-excavation

C4.2.4 Conglomerate and rock removal

C4.2.5 Excavation with water presence

C4.2.6 Removal of water and/or excavated Material

C4.2.7 Backfilling

C4.2.8 Compacted backfilling with natural soil

C4.2.9 Compacted backfilling with granular material iii

C5. Stabilized base and sub-base

C5.1 General

C5.2 Materials

C5.3 Mix design

C5.4 Mixing

C5.5 Placing, compaction and finish

C5.6 Construction joints

C5.7 Curing

C5.8 Final delivery and cleaning

C5.8.1 Final delivery

C5.8.2 Terrain and buildings cleaning

C6. CONCRETE

C6.1 General

C6.2 Properties and characteristics of concrete

C6.2.1 Applicable publications

C6.2.2 Cement

C6.2.3 Sand (fine aggregate)

C6.2.4 Gravel (coarse aggregate)

C6.2.5 Water

C6.2.6 Additives

C6.2.7 Hand mixing

C6.2.8 Mechanical concrete mixer

C6.2.9 Mixing while in transit

C6.2.10 Sleeves in concrete

C6.2.11 Anchors and fittings

C6.2.12 Construction Joints

C6.2.13 Concrete casting and vibration

C6.2.14 Concrete strength

C6.2.15 Strength testing

C6.2.16 Test approval

C6.2.17 Concrete curing

C6.2.18 Concrete defects reparation

C6.3 Formwork iv

C6.3.1 General

C6.3.2 Wood Formwork

C6.3.3 Plywood formwork

C6.3.4 Metal formwork

C6.3.5 Other materials

C6.3.6 Formwork construction

C6.3.7 Non-exposed concrete formwork

C6.3.8 Formwork erection

C6.3.9 Formwork removal

C6.3.10 Formwork reuse

C6.4 Reinforcement Steel

C6.4.1 General

C6.4.2 Reinforcement Steel bars

C6.4.3 Welded Steel mesh

C6.4.4 Annealed wire (tie wire)

C6.4.5 Reinforcement fabrication

C6.4.6 Fabrication tolerances

C6.4.7 Placement tolerances

C6.4.8 Samples and testing

C6.4.9 Storage

C6.4.10 Hooks and bends

C6.4.11 Reinforcement cleaning

C6.4.12 Rebar placement

C6.4.13 Supports

C6.4.14 Inspection

C7. METALS

C7.1 Applicable publications

C7.2 General

C7.2.1 Approval requests

C7.2.2 Structuration

C7.3 Metal fabrication

C7.3.1 Material handling

C7.3.2 Resistance and specifications v

C7.3.3 Materials

C7.3.4 Fabrication and labor

C7.4 Construction and assembly

C7.4.1 Fabrication and mounting

C7.4.2 Reference standards and materials

C7.4.3 Joints

C7.5 Welding

C7.5.1 General

C7.5.2 Welding procedures

C7.6 Metal surface finish

C7.6.1 General

C7.6.2 Work that must be done in shop

C7.6.3 Work that must be done on-site

C7.7 Erection and assembly

C8. SEALANTS AND WATERPROOFING

C8.1 Sealants and water repellants

C9. FLOORS

C9.1 Broom Finished Concrete

C10. MECHANICAL INSTALLATIONS

C10.1 Applicable publications

C10.2 General

C10.2.1 Approval requests

C10.2.2 Samples

C10.2.3 Drawings and specifications

C10.2.4 Scope

C10.2.5 Approval

C10.2.6 Brands and models

C10.2.7 As Built drawings

C10.3 Construction

C10.3.1 Equipment and material management

C10.3.2 Materials

C10.3.3 Supports

C10.3.4 Installation considerations vi

C10.3.5 Tests

C10.3.6 Work reception

C10.3.7 System performance guarantee

C10.4 Protection

C10.5 Potable Water System

C10.5.1 Potable Water Connection

C10.5.2 Water Interior Network

C10.5.3 Pipes and Accessories

C10.6 Wastewater

C10.6.1 General

C10.6.2 Approvals

C10.6.3 Pipe installation for external work

C10.6.4 Pipe installation for interior work

C10.6.5 Accessories

C10.6.6 Tests

C10.7 Sanitary Devices

C10.7.1 Installing Sanitary Devices

C10.7.2 Washbasins

C10.7.3 Toilets

C10.7.4 Stainless Steel Sink

C10.7.5 Shower Enclosure Cabin

C11. ELECTRIC SYSTEM

C11.1 Electric Distribution Boards

C11.2 Illumination

C11.3 Power Outlets

C11.4 Ground Net

C11.5 Conduit System

C11.6 Pipes

C11.7 Boxes

C11.8 Conductor

C12. FIRE DETECTION SYSTEM

C12.1General

C12.1.1 Scope vii

C.12.1.2 Requirements and regulations

C12.1.3 Documents to be prepared

C.12.1.4 Construction of the Fire Protection System

C.13 OTHERS

C13.1 Cyclone Mesh Enclosures

C 13.1.1 Materials to be used

C13.1.2 Execution

C13.2 Cyclone Mesh Enclosure Roof Cover

C.14 PROVISION AND INSTALLATION OF CONTAINERS

C14.1 Containers for Mobile Camp

C14.2 Furniture and Equipment for Containers

C1. GENERAL DESCRIPTION

The Embassy of the United States of America, in cooperation with the Costa

Rican “Sistema Nacional de Areas de Conservación”, SINAC, is heading an infrastructure project consisting in the construction of a mobile camp.

The overall intent of the contractual effort for this project is comprised of the following works:

1- Preliminary Work

2- Existing road improvement and access construction

3- Camp slab and boat ramp construction

4- Drinking water system

5- Waste water system

6- Electrical system

7- Provision and Installation of Containers

The project will be build using the designs developed by Estruconsult and the

INL Technical Advisor Eng. Mario Narváez, which are presented in drawings. The existing facilities are located in Sierpe district, Osa canton, Puntarenas province, Costa Rica.

The project shall be conducted in accordance with the plans and specifications detailed in this document.

C2. SPECIFIC TASK

C2.1 Preliminary work

Preliminary work includes the implementation of temporary facilities for the workers according to the specifications detailed in C4.1.4.

The preliminary work shall also include a technical review of the designs technical specifications in order to comply with all the established requirements.

The Contractor will also be in charge of obtaining construction permits from the appropriate local authority (Osa municipality). The Contractor shall therefore provide all the qualified technical staff in charge of the project’s development in accordance to local regulation, based on provided designs, drawings and this document’s specifications.

C2.2 Existing road improvement and access construction

The Contractor must improve the existing ballast road, ensuring a level and clean surface, using the appropriate equipment to apply a cement-based stabilized base type BE-35, 20 cm thick. This will consist of a cementitious base of granular material stabilized with hydraulic cement in order to reach an average compressive strength of 40 kg/cm2. The contractor must present the mix design prior to the start of work. This will be perform in accordance to drawing S0.3 and detail BE1.

To achieve the required width in the access road, the construction of the access to the boat ramp and the maneuvering yard next to the slab of the containers, the contractor must remove the vegetable layer and place a 95% compacted ballast base of Modified Proctor, on which a cement-based stabilized base of type

BE-35, similar to that indicated above, will be build. The above according to the indicated in the sheet S0.3 and the detail BE2. Contractor must use a woven geotextile between the base and subbase interface, equal or superior to TR4000 from Amanco, so that pressure is distributed evenly across the terrain.

C2.3 Camp slab and boat ramp construction

For the boat ramp, the contractor shall construct a concrete slab reinforced with polyolefin copolymer fibers and fibrillated polypropylene fibers, similar or superior to Ruredil XF-54, which shall have at least a compressive strength of

240 kg / cm2. The finish of this slab will be “brushed” and rough, all according to detail 9 of sheet S0.3, and using detail 10 for the joints between different phases of concrete.

For the container area, the contractor must build a concrete slab reinforced with

Ruredil XF-54 fiber or higher, which will have at least a compressive strength of

280 kg / cm2, according to detail PV01 of sheet S0. 5. A subbase layer of 50cm

(minimum CBR of 30) and a base layer of 30cm (minimum CBR of 70) will be used, both compacted to 95% of the Modified Proctor. The contractor shall install a woven geotextile between the interfaces of the subbase and the ground, as well as the base and the subbase, to ensure a uniform distribution of the pressures on the ground. Additionally, concrete supports for the placement of the containers must be built, according to detail 4 of sheet S0.5. Details JP1 and

JP2 must be used for the floor joints of the slab.

C2.4 Drinking water systems

The contractor must build the potable water system necessary for the complete functioning of the mobile camp. The above according to the mechanical drawing

M-0.2. PVC pipes and fittings, as well as any other permitted material, must comply with the specifications and indications provided by the respective manufacturer. The drinking water supply will come from an existing well on the property, which water will be treated through a chlorination and purification system to make it suitable for human consumption. This system will be composed, at least, by:

A centrifugal pump (equal or similar to CM3-4 from Groundfos)

Two 4.5”x20” sediment filter for 20 microns and 5 microns (washable

Harmsco cartridges)

A chlorination system/dosing pump (equal or similar to SEKO AML200)

A zeolite filter (equal or similar to FC15Z-263/740 PENTAIR – USA)

A carbon filter (equal or similar to FC15-263/740)

An ultra violet light filter (equal or similar to Viqua VH410)

A constant pressure pump (equal or similar to SCALA2 from Groundfos).

The Contractor will be responsible for carrying out physical-chemical tests on water, ensuring that the system to be installed is suitable for treating the water coming from the well.

The contractor must install one elevated tanks with a capacity of 5,000 liters each, equal or similar to the "Tricapa Standard Tank" of the MuchoTanque brand, for the storage of the water extracted from the well. This includes the construction of the support structure, in accordance with the detail provided in drawings.

The system will supply water to containers 301, 401, 402, 501, and 502, corresponding to the men’s dormitories, women’s dormitories and the kitchen, as well as the exterior water connections.

The contractor shall provide, place, connect, adjust and test all the pipes, fittings and special devices, as well as any valves required, which together serve for the conduction of drinking water. The drinking water will come from the public service.

C2.5 Wastewater system

The contractor shall build all the mechanical systems necessary for the complete function of the camp, including the greywater system and wastewater system.

All of these according to mechanical drawing M-0.1. Aluminum, and any other type of piping and associated connections, must comply with this specification and follow each manufacturer’s manual indications.

The Contractor shall build the sewage system, for the containers 301, 401, 402, 501, and 502, corresponding to the men’s dormitories, women’s dormitories and the kitchen. The water will be directed towards a treatment system, consisting of a septic tank equal or similar to "MT 7000-S" and a bio-filter "BK 2000", of the brand MuchoTanque, to finally be evacuated by the way of drainage ditches, according to the detail indicated in construction drawings

C2.6 Electrical system

The contractor shall build the electric system to meet the complete requirements identified in drawings EL-1.1 to EL-1.2 and according to the Local Electric Code.

This work must be performed under the supervision of a certified professional

(Electric Engineer).

The scope of this document and the construction plans comprise exclusively the external electrical works of the camp, excluding the distribution systems, lighting and internal electrical panels of each container. The contractor will build the exterior electrical system in accordance with the complete requirements identified in the sheets cited above.

The electricity supply for the camp will be provided by a 25 kW electric plant, 120/240 V with automatic start, single phase, of a recognized brand and complying with national regulations and laws, as well as an automatic transfer switch 3P2T, 120/240 V, 225 A. A

The contractor must also build a fuel storage tank, which will supply the power plant. All the electrical connection will travel underground, using PVC SCH40 pipe, and registration boxes, according to what is indicated in the drawings.

The camp will be illuminated by means of 4 light posts, according to what is indicated in sheet EL-1.1, as well as post detail indicated in structural drawings, equal or similar to LED Dolphin 120W of the Sylvania brand. The ramp will be illuminated by solar lamps placed in concrete posts, as indicated in drawing S0.6.

C2.7 Provision and Installation of Containers

The Contractor shall provide and install 7 Containers at Sierpe according to the design established in drawings C-01, C-02, C-03 and C-04 and to the specification C.13 detailed in this document. The following containers are part of the project, the Contractor shall provide and install them in order to be used as soon the project is finished and according to the contract:

Containers for Offices (100-102): two 20’ Standard Containers for Offices that includes three work stations each.

Container for Kitchen and dinning room (301): One 40’ High Cube Container that includes one dinning room for 12 people and one kitchen.

Containers for Men’s barracks (401 -402): Two 40’ High Cube Containers for 16 people that includes two dormitories and two bathrooms each.

Containers for Women’s barracks (501 -502): two 20’ Standard Containers for 8 people that includes one dormitory and one bathroom each.

The Containers’ finishing shall be according the specifications detailed in this document.

According to drawings the project will have two simple containers for storage

(201 -202), these containers are not part of this contract; the containers 201 and 202 will be provided by INL in a future.

C3. GENERAL SPECIFICATIONS

All work shall be carried out in strict compliance with all contract clauses and these technical specifications. In the event that the Contractor discovers discrepancies contained in the various design/technical documents, Contractor must immediately notify the Contracting Officer Representative (COR) before taking any other action.

C3.1 Quantities

This contract is based on a lump sum priced solicitation. Any quantities indicated in the specifications and drawings are for reference only and the Contractor is responsible for providing quantities needed to complete the work, without any price adjustment after award.

C3.2 Trials and Tests

Materials, permanent equipment, its accessories and other elements used in the project, shall be subject to tests necessary to verify their compliance with specifications, properties and characteristics, in accordance with the specified requirements and tolerances, in line with the use for which they have been intended.

Materials, equipment, accessories or elements that have not been accepted by the COR (Contracting Officer Representative), shall be withdrawn from the work site or replaced, at Contractor’s cost.

Laboratory tests can be carried out, according to the specific case, at the work site or in laboratories previously authorized by the COR. Materials that bear quality certificates issued by ISO or its equivalent, do not need to be routinely tested. Costs of laboratory trials and tests shall be for the account of Contractor.

The COR shall be able to carry out special trials and tests at any time if it is needed to clarify the quality of any item.

C3.3 Work Execution

The different items in the construction schedule shall be carried out in a gradual and progressive manner, without starting any work that could later be affected by other items that have not been concluded or that lack an adequate support or safety measures, taking care that work that has been finished is not affected by weather or other elements.

The Contractor shall be responsible for maintaining quality of work by following proper operation procedures in construction.

Throughout the different stages of construction work, Contractor shall obtain approval, from the COR, in order to continue with subsequent stages of construction. Before receiving approval to continue through the various stages, samples of completed work shall be tested to verify the quality of the work.

The Contractor shall provide a construction schedule in which all the works shall be detailed with the date of performance and delivery.

C3.4 Cost of the Project

The Contractor shall include all the costs of the materials, labor, transportation, and materials testing that will be needed to complete the project and comply with all the specifications stated in this document.

C4. TASK SPECIFICATIONS

C4.1 Preliminary Work

C4.1.1 Demolition and land clearing

This clause includes tree trimming work (any required permissions apply) and any shrub, trunk, root, grass and topsoil layer removal. The aim of this is to clear the area on and around the footprint that is deemed unsuitable for foundation work or terrain leveling works, including the removal trees and demolition of the construction indicated in the demolition plan, in structural drawings. Only the trees indicated in sheet S1.2. are to be removed, leaving any other tree untouched.

The Contractor shall perform any land clearing, root, tree and vegetation removal, and topsoil and organic silt elimination when present. Any elements that interfere with the construction work, such as old foundations, rocks, etc., must be removed by the Contractor. All of the materials removed from the project’s site, such as topsoil and debris, must be transported by the Contractor and disposed of in an appropriate place outside the property, which selection, along with any implicit technical and environmental repercussions, is the

Contractor’s responsibility

C4.1.2 Leveling and plotting

Before construction start, the Contractor shall define the project’s components layout and, if necessary, construction levels in accordance to the provided drawings. During this same phase the Contractor must verify all of the drawings information, and correct them if any discrepancy exists between real, on-site, dimensions and those provided in drawings by the designer.

To comply with these requirements, the Contractor shall provide an expert topographer supported by precision equipment such as: total stations, levels, measuring tape, and any other required equipment for layout, alignment and terrain leveling. The use of this equipment will be performed so that machinery works will not interfere. Any additional alignment or leveling job cost will be the

Contractor’s responsibility.

C4.1.3 Warning Signs

The Contractor shall provide all the necessary signs and announcements to prevent accidents according to the safety plan, which shall have the approval of the COR. Signs shall be made of acrylic or galvanized sheets painted with a yellow background and with red or black letters.

C4.1.4 Temporary Structures

Temporary structures, for the Contractor’s personnel use, will be implemented for use during the project’s duration. It is the Contractor’s responsibility to implement offices, warehouses, provisional bathrooms and the guardhouses required for their own use, with a temporary connection to a potable water and sewage system prior to commencing construction. One sanitary facility shall be implemented for every ten workers, with an additional one for the technical staff.

The Contractor will be responsible for cleaning and maintaining these structures.

The materials used for these provisional facilities can be metal, concrete, or wood, as long as they are secure and provide a private area. The COR can demand changes or improvements of the provisional facilities at any time if he determines that the Contractor is not providing a clean area with sufficient privacy and safety.

C4.2 Earthwork, Excavation and Backfilling

The work described in this chapter includes excavation and backfilling, as well as carrying, piling up and removing excavation material necessary for the construction of the building, piping, and all elements indicated in the project drawings.

C4.2.1 Leveling and land clearing

To determine final levels, theodolites or precision instruments will be used. If there are considerable differences with the specifications in the drawings, the

COR shall be notified and only through a report of mutual agreement will the new levels be determined.

The residual material must be removed and placed outside the construction site in places approved by the local authority.

C4.2.2 Excavation

Generally, excavation is understood as the removal of volumes of land or other materials for the purpose of forming spaces for construction, foundations, structures, buildings, roads, etc. Excavation shall be done according to the heights, limits, elevations, gradients and sections set forth in the structural, architectural, and sanitary drawings, save for different or real conditions of the project.

During excavation, material satisfactory for backfilling shall be stockpiled in an orderly manner at a distance from banks of the trench equal to ½ the depth of the excavation, but in no instance closer than 60 cm. Excavated material not required or not satisfactory for backfill shall be removed from the site, without affecting the adjacent properties. The material produced from excavation will be temporarily disposed of on the sides of excavations, so that it will not impede the execution of other work.

The final excavation that will be performed in the places where specific exterior works made out of concrete will be built, shall be carried out as close to the pouring of concrete to avoid any alterations due to bad weather.

In no case shall excavation be performed to a depth in which the soil is loose. If this happens, it will be considered as an “over excavation” that will be corrected by the contractor according to the project’s specifications.

If, in the Contractor’s or COR’s opinion, the bottom of the ditch is not strong or is unstable, over-excavation will be carried out until solid ground is reached, otherwise another solution shall be jointly agreed upon by the Contractor and the COR.

It is the Contractor’s duty to protect the stability of the adjacent properties while excavation is carried out. This should be done in a way that guarantees the stability of those buildings without causing any damage.

Excavation shall be protected against rain, landslides and other excavations.

The Contractor will protect the personnel excavating in ditches and, if for safety reasons it is deemed necessary, the contractor shall provide timbering and shoring.

This shoring shall be reviewed and approved by the COR, and the Contractor will protect the shoring and will be removed after the excavation has been performed.

For piping placement in excavation, the filling will be laid as a first step to cover a height of at least 20 cm above the highest part of piping and shall be compressed in accordance with the article of this section. Excavation will be done from the ditch in accordance with the gradient slope and required transversal lines for placement of piping as indicated on working drawings.

C4.2.3 Over-excavation

The term over-excavation, for the purposes of the job to be carried out, is understood as excavation outside the lines and levels set forth in the drawings, the specifications and/or the COR’s instructions.

If over-excavation is done, removal should go up to the required level and filling with soil, granular material or concrete or any other material approved by the

COR; compressing will be done with adequate water content, in layers that will not exceed a thickness of 15 cm, using an appropriate mechanical compactor.

The compaction process shall be done according to the regulations established by the standards of the American Association of State Highway and

Transportation Officials (AASHTO T-130). The material to be used shall be selected granular material according AASHTO 145.

The Contractor agrees not to receive any additional payment for over-excavation that may result from the conditions of the land, the action of natural agents, operations that are executed to facilitate the construction, and mistakes made by the Contractor.

C4.2.4 Conglomerate and rock removal

The process of excavation when hard materials are found which cannot be loosened through ordinary methods is understood as conglomerate and rock excavation where the use of shovels, pickaxes, backhoes, or excavators is not sufficient and explosives, mechanical hammers, wedges, or sledge hammers or other similar are absolutely necessary.

If a rock is found in pieces, only fragments greater than 200 cubic decimeters will be considered as rock.

When removing rock or masonry fragments from a ditch is necessary, and if they form clusters that do not have to be totally extracted in order to erect structures, those pieces excavated within the presumed boundaries will be considered as rock, although their volume could be smaller than the one indicated in the above paragraph.

If the bottom of the trench (made to install pipelines) is made up of conglomerate or rock, excavation will be carried out up to 0.15 m below the seat of the pipe and it will be filled later with sand and fine gravel.

When excavation is carried out on fixed rocks, the use of explosives will be allowed, provided that they do not alter the land adjacent to the excavation works and with a prior written authorization from the COR.

C4.2.5 Excavation with water presence

The excavation with presence of water may be caused by water coming from the underground, rainwater, floods, operation of the construction, sewage and others.

Excavation cannot be executed in the presence of water, whatever its origin, and therefore due precautions and protections must be taken, as construction techniques advise in these cases. The presence of water makes work more difficult and the safety of the people and the projects themselves decreases.

Therefore, the Contractor is required to take due precautions to eliminate water in excavation sites by using stake boards, cofferdams, pumping, drainage, curbs, etc.

When placing stone masonries, concrete structures, or any structure, the

Contractor will insure that water is not present in excavations, and that it will remain so until mortar and concrete have set.

None of the excavations should have water present before placing the pipes, and under no circumstance will they be placed under water. The trenches shall remain dry until the pipes have been totally coupled and the welded junctions are completely dry.

C4.2.6 Removal of water and/or excavated Material

Waste removal is defined as the method of transportation of the materials produced by excavation, which should have a specifically determined place for disposal approved by the local authority.

When there is an excess material, the Contractor shall remove it and place it outside the area of construction where such material will not obstruct watercourses or cause detriment to the neighboring areas.

Excess or waste material should not be located in properties adjacent to the construction site unless the Contractor receives written authorization from the owners of such properties.

The material produced by excavation that will not be used for the construction of the project shall be removed from the site using heavy mechanical equipment in good condition, without causing vehicle transit interruption or neighbors’ annoyance.

C4.2.7 Backfilling

Backfilling is defined at the sections indicated by the project, the existing gaps between structures and excavations, or between the structures and the natural soil in such a way that any point of the finished section will remain at a distance greater than 10 centimeters from the corresponding section of the project. The backfilling process will be carried out using earth, gravel, sand or rock with approval from the COR.

Prior to backfilling, the land shall be free of debris, trunks, branches, etc., and in general of all organic material and all the material that is not appropriate for backfilling. The COR will approve the material that will be used for backfilling in advance and the material will come from the excavation itself or other extraction sites.

The backfilling will be done according to the project specifications and according to the lines, levels and gradients described in the architectonic and structural drawings. The Contractor is required to obtain, transport and maintain the necessary material for backfilling, either from the excavation site or from qualified quarries.

Special care will be given by not using the mechanical compactor in areas close to buildings or existing construction inside or outside of the property. If any damage occurs, this shall be repaired and costs assumed by the Contractor.

The refill and/or cover of any excavation that contains lines or pipes installations and other services will not proceed until they have been placed and tested as well as approved and accepted by the COR.

The backfilling for subflooring will be placed and mechanically compacted in beds of 0.20m thick according to the D698-64T specifications of the American Society for testing and Materials (ASTM).

Backfilling with gravel, sand or ground stone for formation of drains or filters shall be consistent with the grain grading specified in the working drawings;

materials will be sieved and washed if required. For filter formation, the materials will be placed in such a way that the higher grade particles remain in contact with the structure and the ones with lesser diameters in contact with the natural terrain, unless otherwise indicated.

C4.2.8 Compacted backfilling with natural soil

Compacted backfilling with natural soil is defined as placing horizontal layers of the existing soil, with a thickness of 20 cm, with the humidity that the material requires to get a mechanical compression to 95% minimum of the density of the

Proctor Standard measure. Each layer shall be evenly compacted on the entire surface by pneumatic rammers or other construction equipment until obtaining the maximum compression possible with the use of these tools. The material to be used in this backfilling shall be free of organic residues and waste. Prior to backfilling, the land shall be free of debris. The COR will approve in advance the material that will be used in the backfilling process. The compaction process shall be done according to the standards of the American Association of State

Highway and Transportation Officials (AASHTO T-130).

If the approved material for this backfilling is not enough to reach the levels specified in the project design, the Contractor shall complete the volume needed, with granular material according to the specification for “Compacted backfilling with granular material.”

The Contractor shall carry out laboratory tests to guarantee the compliance with the aforementioned specifications and the cost of these tests will be assumed by the Contractor.

C4.2.9 Compacted backfilling with granular material

Compacted backfilling with granular material is defined as placing horizontal layers of sub-base to a maximum thickness of 20 cm. Each layer will be compacted evenly on its entire surface by pneumatic rammers or heavy construction equipment until obtaining the maximum compression possible with the use of these tools. Compaction shall be carried out using sheep foot rollers, pneumatic-tried rollers, steel-wheeled rollers, vibratory compactors, or other approved equipment. The thickness of the backfilling shall be in accordance with the structural and architectonic detailed drawings. Prior to backfilling, the land shall be free of debris. The COR will approve in advance the material that will be used in the backfilling process. The compaction process shall be done according to the standards of the American Association of State Highway and

Transportation Officials (AASHTO). Compacting shall be have a 95% of the maximum density (Proctor Test). The material to be used shall be granular selected material according AASHTO 145 (A1, A2, and A3).

C5. Stabilized base and sub-base

For the purpose of this specification, road improvement using stabilized base consists of constructing one or more layers of an aggregate and cement mix, adding ash or lime as required, above a smooth subgrade. The main reference document for this section is the “Manual De Especificaciones Generales Para La

Construcción De Carreteras, Caminos Y Puentes CR-2010” created by the Public

Works and Transport Ministry (MOPT) of Costa Rica.

C5.1 General

Additives used for stabilized base construction shall be stored in closed, waterproof recipients, protected against weather elements. Aggregates must be kept at an optimum humidity level, according to mix design and compaction requirements.

If the stabilized base is placed over an existing way, surface preparation is necessary prior to any other work. In case that subgrade exists, all organic material up to 15 cm depth will be removed, scarifying and removing any surface irregularity, and then defining the surface until it is uniform. A 1.5 cm tolerance will be allowed when working with soil and 3 cm when working with rock, with respect to its required alignment, transverse section and slope.

If reconditioning must be done in an aggregate surface, scarification will be performed up to a 20 cm depth or the thickness of the aggregate layer, eliminating any irregularity with a 2 cm maximum tolerance. Surface compaction will be done using 10 cm to 15 cm thick layers, measured after compaction, maintaining the material’s optimum humidity for this purpose.

C5.2 Materials

Materials used for base and sub-base construction must comply with the following requirements:

Aggregates: Hard, durable particles or ground rock, slag or ground gravel.

They shall not contain elongated particles or plant debris. Additionally, they must comply with the specifications presented in section 703.05 of the document CR-2010, cited above.

Cement: Cement used for stabilized bases must be Portland cement, in compliance with the AASHTO M 85 standard. Additionally, they must comply with the specifications presented in section 701.01 of the document CR-2010, cited above.

Lime: Lime used for road improvement must be quicklime or hydraulic lime, complying with the AASHTO M216 standard.

Water: Drinking water from a known source shall be used, safe for human consumption and AASHTO M157 compliant.

C5.3 Mix design

Mix design used for stabilized bases and sub-bases must include a minimum average compressive strength of 3,0 MPa, without any sample having a lower compressive strength than 2,0 MPa. Mix design can be previously defined by the

COR, but the Contractor will need to present a mix design, that complies with the previously described parameters, if required.

In the next table, the allowed percentage range of aggregates and cement is presented:

Material Percentage (%)

Aggregate 90-96

Hydraulic Cement 4-10

In cases in which ashes and lime are used for the stabilized base mix, the following percentages will be allowed:

Material Percentage (%)

Aggregate 90-96

Ashes 6-20

Lime and hydraulic cement 2-5

The mix design, unless otherwise specified, must also include:

Each material’s source

Applicable tests results

Aggregate grain size

Aggregate Sample

Ash sample

Lime sample

Hydraulic cement sample

Retarding admixture simple

Mixing and placing of stabilized base will only be started once the COR approves the mix design.

C5.4 Mixing

No layer of stabilized base will be placed if the underlying surface is saturated or rainy conditions are present so that the mix integrity is preserved.

Components must be mixed used appropriate equipment that allows for a uniform mix. Manual mixing shall not be allowed. Material percentages in the mix will have the following tolerances, based on mass:

Material Tolerance (%)

Aggregate ±2 %

Ashes ±1,5 %

Lime and hydraulic cement ±0,5 %

Admixtures ±2 %

Water ±2 %

The maximum acting time of a retarding admixtures will be two hours, dissolving it in water and then adding it uniformly to the mix.

C5.5 Placing, compaction and finish

Once the optimal humidity content for the material that will be used is determined, the aggregate will be adjusted to a humidity content within a 2 % range of the optimal value. The mix will be placed and compacted over a previously prepared surface, in layers up to 15 cm in thickness after compaction.

The maximum mix density will be determined according to the AASHTO T 180 method D, standard. Each layer will be compacted in all its width, starting at the borders and moving towards the center, parallel to the center line. In those places in which the standard compaction equipment has no access to, or the necessary finish can’t be achieved, the use of secondary equipment such as rammers or other approved compaction equipment will be necessary.

Each layer shall be compacted until a 95 % of its maximum density is reached.

The maximum allowed tolerance for the finished surface is 1.5 cm in every 3 m, using a 3 m ruler for testing purposes. Areas which don’t comply with this requirement must be corrected by: scarifying the material, adding or removing the mixture (as required) and then compacting and leveling it.

No layer shall be left more than thirty minutes without compaction, and one hour from when water is added to the mix and providing the appropriate finish.

C5.6 Construction joints

For lime and ash mixes that have not begun setting (less than 24 hours after placing), new and old layers will be joined by mixing 0,5 m of the old layer before placing any new section. A 50% of the original lime or ash content will be added to the new mix.

For cement based mixed or lime and ash mixes left to set for more than 24 hours, a transverse joint will be cut in the set zone, forming a vertical cut.

C5.7 Curing

Each layer will be kept moist until the next layer is placed by applying pressurized water using a spray bar that produces a fine and uniform spray. The maximum allowed time between layers will be of 7 days after compaction, except when a rapid setting asphalt emulsion is used, in which case the allowed time will be incremented to 21 days.

If the stabilized material loses its condition, density or finish before the next layer is placed or delivery to the COR, remixing and compacting again (using any necessary admixtures) will be done until the necessary finished and strength are achieved.

Vehicle transit over unfinished stabilized base layers will be completely prohibited.

C5.8 Final delivery and cleaning

C5.8.1 Final delivery

The Contractor may request final reception of the road or way only once all the contracted works, in compliance with the specifications, are completely finished to the Owner’s and COR’s satisfaction. The delivery of piping networks, for fresh, waste, are included, and they must be free of aggregate or any other material contamination due to the construction process.

C5.8.2 Terrain and buildings cleaning

The contractor must leave the zone in which work has been done completely clean and trash free. Likewise, a complete cleaning must be done prior to delivery.

Stains of any type, in sidewalks, transit layers, walls or any other surface, won’t be accepted. Obstructed or dirty drain pipes also won’t be accepted, and they will be approved only once they are completely cleaned and functional.

All equipment and material, and any other accessory, used for construction must be removed from the project.

C6. CONCRETE

C6.1 General

The production, transportation and placing of concrete used to build the project must comply with the recommendations of the American Concrete Institute

(ACI), which are found in the “Specifications for Structural Concrete For Building”

ACI 301 Committee report, last revision. For all of the other processes involved with reinforced concrete, all of the recommendations of the ACI 318 “Building

Code Requirements for Reinforced Concrete”, last revision, must be followed.

Compliance with the standards and specifications of the American Society for

Testing and Materials (ASTM), mentioned in this document and related to reinforced concrete, is mandatory.

C6.2 Properties and characteristics of concrete

C6.2.1 Applicable publications

Concrete building, be it onsite or ready mix, must follow the technical and constructive standards presented in the following publications, in its current versions:

● ACI

● CRSI

● Applicable ASTM standards

C6.2.2 Cement

Cement used in any work execution, must be Portland Type 71-Normal cement, compliant with the ASTM C-150 standard. It must arrive the project´s warehouse in its original packing, without any sign of tears or material hardening. If the COR detects any anomalies, he will be able to request a partial or complete product lot substitution.

Cement must be kept in a fresh place and covered in a way that it isn’t exposed to rain or affected by humidity. The product is allowed to be stowed in 10 cm tall wooden pallets in ten bag stows as maximum.

C6.2.3 Sand (fine aggregate)

The sand used for concrete producing must be river sand, except in special cases. To verify its quality, samples must be approved by the COR, especially when using quarry sand. In any case, sand must have a siliceous-calcareous origin, free from any deleterious substance such as, clay, silt, lignite or alkali. It must be free of any dirt, and kept dry so that its humidity levels are according to the mix design and therefore the volumetric or by weight dose used to make concrete. Sand used for concrete elements shall comply with the ASTM C33 standard, in its current version.

The used sand must have grain sizes within the following limits:

3/8” Sieve --------------------------- Percentage passing: 100.

# 4 Sieve --------------------------- Percentage passing: 95 a 100.

# 8 Sieve --------------------------- Percentage passing: 80 a 100.

#16 Sieve ---------------------------- Percentage passing: 80 a 100.

# 30 Sieve --------------------------- Percentage passing: 25 a 60.

# 50 Sieve --------------------------- Percentage passing: 10 a 30.

# 100 Sieve -------------------------- Percentage passing: 2 a 10.

C6.2.4 Gravel (coarse aggregate)

Coarse aggregate consist of materials which main content is gravel or broken stone. These materials must be clean and free of any substances such as soil, clay, silt and other organic materials which could produce fake adherence in the concrete mix.

The required measures for coarse aggregates used for concrete, are:

● For thin, reinforced concrete elements, less than a fifth of the mold’s lesser dimension and less than three fourths of the space between rebar.

● For elements having, approximately, a 6 cm thickness, the use of aggregates bigger than 25 mm is prohibited.

● For elements such as beams, columns and any reinforced concrete element, aggregate with a diameter less than 38 mm must be used.

● For non-reinforced concrete elements, aggregate with a diameter between

38 mm and 50 mm can be used.

● For massive concrete elements, aggregate with a diameter up to 150 mm can be used, prior to the COR approval.

● Coarse aggregate storage must be done in a way that different sized products don’t mix, for which wooden board enclosures, forming quadrants, with enough height for stocking more material. Each enclosure must have a sign that indicates the diameter of the aggregate. Cone shaped piles are forbidden, and a flat surface must be maintained while in storage, so that any debris can be easily removed and won’t easily mix with the clean aggregate.

C6.2.5 Water

All of the water used in the mixing, curing and mortar production, must be clean, potable water. The water quantity to be used in each concrete pouring, must be according to the specific dosage presented in the following table:

WATER/CEMENT RATIO BY

WEIGHT

PROBABLE COMPRESSIVE STRENGTH

AT 28 DAYS

0.45 350 Kg/cm2

0.53 280 Kg/ cm2

0.62 225 Kg/ cm2

0.71 175 Kg/ cm2

C6.2.6 Additives

The use of any concrete additives, i.e. setting accelerants, retardants, or hardeners, must be done after the COR request or approval. In case that the requested additives aren’t commercially available, any similar products must be submitted for approval with its respective manufacturer’s technical manual. Any approved additive must arrive to the construction site in its original package.

C6.2.7 Hand mixing

Concrete production using any manual methods is not allowed. In especial cases in which, for example, small volumes are required, excessive travel distances or difficult access circumstances are present, the COR can eventually allow, without any responsibility, the use of hand mixed concrete.

C6.2.8 Mechanical concrete mixer

The mechanical mixing of concrete is the only type of process allowed. The COR has the authority to inspect and approve all of the equipment used for mixing concrete. The requisites that need to be met, are:

All of the equipment employed must be in good mechanical and operation conditions. A water weight or water level controller for the mixer is desirable.

The mixer´s barrel size must be according to the concrete volume to be poured.

Concrete mixers with a capacity of less than a cement bag are not allowed to be used on-site.

All of the necessary equipment for any given pouring job to be continuous, free of any interruptions, must be available in the project. The COR can request, according to the volume of any pouring job, the addition of mixers and other equipment.

When placing any concrete, the concrete mixer and any other equipment used during the process must be clean. When the job is finished, or a pause larger than two hours happens, the mixers and any equipment involved must be washed.

All materials must be introduced at the same time in the mixer, so that the mix can be as homogenous as possible

The mixing duration cannot be less than two minutes after pouring all the materials inside the drum.

The time for the concrete to be cast in place, after pouring all the materials in the mixer, cannot be higher than thirty minutes.

C6.2.9 Mixing while in transit

Dry, on-plant dosed, concrete and mixed in transit to the Project can be used.

The truck used must be a drum mixer. Each concrete shipment must complete at least fifty revolutions. The mixing speed will be higher than four drum revolutions per minute and no larger than 225 ft. of drum circumference per minute. The revolutions must be continuous once all of the materials are introduced. The maximum time between concrete deliveries shall not be longer than twenty minutes.

C6.2.10 Sleeves in concrete

The use of sleeves inside reinforced concrete is considered as a non-desired practice. Only special cases, authorized by the COR and indicated in redline drawings, will be allowed with previous presentation of workshop drawings and diagrams. In the case that sleeves are allowed, they shall be located in the central third of the beam’s longitude and the central third of its height. When using pipes smaller than 25 mm in diameter, the separation between each sleeve must be of 25 cm. If the sleeve uses pipe with a diameter between 64 mm to

100 mm, their separation must be at least 50 cm. Additionally, two #3 bars, 50 cm long, frames will be placed, or what the COR indicates.

If the sleeves are placed with one or both of its ends in contact with the ground, plastic covers must be placed at the ends. If the pipes go through a tank’s walls, instead of sleeves a pipe with the same characteristics as the rest of the piping will be placed, with a flange in the walls mid-section.

C6.2.11 Anchors and fittings

Any anchors and fittings necessary to join concrete elements to metal or wood elements are shown in the project’s drawings. The plates or steel sections used to produce them must meet the established criteria in the chapter “Steel

Structure” of this document. Rebar must comply with the requirements established in the steel chapter of this document, having a yield strength equal to fy = 2800 kg/cm2, unless otherwise specified. In any other case, experimental and documental evidence of the element’s weldability must be provided.

The joining element’s size and shape will be indicated in the corresponding drawing, but alternative designs, that facilitates the element’s placement while retaining its structural integrity, can be accepted by the COR. The placement must be done so that formwork removal doesn’t become complicated. During this procedure, the specified opening tolerances must be observed.

C6.2.12 Construction Joints

All construction, vertical or horizontal, joints must be approved by the COR, who will determine where and how it will be built, using the necessary elements (key joints, butt-dowel joint, butt-tie bar joint, etc…). Before the concrete casting, any joint must be moistened and the concrete surface covered with a thick concrete grout.

Contact or isolation joints must be built every time a slab comes in contact with columns, concrete walls, CMU walls or reinforced concrete rigid frames. Isolation joints must be built using expanded polystyrene foam with a 13 mm thickness, or a similar material, adhered with special glue or nails, and the same width of the concrete slab.

C6.2.13 Concrete casting and vibration

The COR shall approve the formwork, molds, temporary structures, and the placement and cover of rebar. He must be notified, five business days in advance, the date and time at which any concrete element will be casted.

All of the necessary equipment for any given pouring job to be continuous, free of any interruptions, must be available in the project. The COR can request, according to the volume of any pouring job, the addition of mixers and other equipment.

Next to the concrete casting place, at least two vibrators in good conditions, with a 65 mm maximum diameter head, will be present. Another smaller vibrator with a 25 mm diameter head, will be available in the project, in the case that thin or densely reinforced concrete elements are needed to be casted.

Casting shall…