Attachment 1 - SOW.pdf

PROJECT NAME:

CONSTRUCTION OF CORNITO ROAD DOME AND COMPONENTS IN ALDEA

CORINTO, MUNICPALITY OF OMOA, CORTES

SPECIFICATIONS

Table of Contents

STATEMENT OF WORK (SOW)

PREFACE

SCOPE AND SPECIFICATIONS

PROJECT REQUIREMENTS

CONSTRUCTION

Construction Services

Construction Requirements

TECHNICAL SPECIFICATIONS

Preliminary Work

Earthwork, Excavation and Backfilling

Concrete Structures

Steel Reinforcement and Metallic Structures

Metallic Roofs

Storm Systems

Electric System

STATEMENT OF WORK (SOW)

PREFACE

The Embassy of the United States of America in Tegucigalpa, through the International

Narcotics and Law Enforcement Agency (INL), has a cooperation program with the Dirección

Nacional de Servicios Policiales Fronterizos (DNSPF). This program is focused on improving the border services to prevent narcotic traffic implementing vehicular check point areas nearby.

In this area of cooperation, INL will build SELF-SUPPORTING ROOFS AND

STRUCTURAL COMPONENTS at the existing check point facilities and improve working conditions to frontier police agents.

The objective of the project is to construct A SELF-SUPPORTING ROOFS AND

STRUCTURAL COMPONENTS to cover the needs Honduras’ National Police (hereafter referred to as the Client) this check point has. This self-supported roof will be constructed in

Aldea Corinto, Omoa, Cortés.

The contractor shall provide all materials, staff, tools, and equipment necessary for the construction of this facility using provided designs.

SCOPE AND SPECIFICATIONS

The purpose of this SOW is to establish the requirements for the construction of the SELF-

SUPPORTING ROOF AND STRUCTURAL COMPONENTS IN ALDEA CORINTO,

MUNICPALITY OF OMOA, CORTÉS. The work includes but is not limited to the following:

Construction Services, labor, supervision, tools, materials, and equipment necessary to perform the design-build, turn-key construction of the self-supporting roof.

The US Government is seeking experienced sources capable of build this project based on design attached to this document. Contractor must provide construction contracting and management services and must be experienced in the coordination of construction efforts in all aspects of new construction. The selected contractor is encouraged to hire local labor and contractors and use local materials to complete the work.

PROJECT REQUIREMENTS

Project shall be conducted according to the plans and specifications detailed in this document.

The Contractor shall perform the following work:

CONTRUCT SELF-SUPPORTING ROOF IN CORINTO BORDER CHECK POINT.

Corinto check point is located southwest from Omoa city, in the department of Cortés.

Approximately 2 hours from San Pedro Sula by car.

Coordinates:

15.5934906 N, -88.3702153 W

Work description:

a) Take away existing billboards and steel frame and relocated them nearby the self- supported roof. Build 2 reinforced concrete foundation footing, pedestals, and steel plates to support and relocate steel frame and billboards.

b) Remove existing trees interfering with installation.

c) Creating foundation footing and pedestals of reinforced concrete, and steel plates with respective anchors. Locations will define in site by INL’s technical advisor.

d) Install steel columns and other steel components to support roof according with structural blueprints.

e) Provide self-supported roof with approximately 363 m2 (14.5 m wide and 25 m long) to cover the area where a trucks scanner has been placed.

f) Install drainage system to channel water away from the roof (gutters and downspouts), a minimums three 4 inches downspouts each side.

g) Submit as-built blueprints at the end of the project in digital format (PDF and DWG)

CONSTRUCTION

Construction Services

Contractor shall complete the turn-key construction of The Self-Supporting Roof and

Structural Components on the selected site in full compliance with the provided designs. Any variances from the designs must be submitted in writing to the CO and receive written approval prior to continuing the construction.

Construction Requirements

The Contractor shall construct in its entirety The Self-Supporting Roof and Structural

Components. Construction should follow all technical specification stated on approved designs. Contractor shall not deviate from the designs provided by INL and the Client without their prior approval.

The supporting documentation provided in addition to this SOW must be taken into consideration. Likewise, in case of conflicts between design details in drawings or schematics, the bidder must consider the most financially and technically critical scenario.

TECHNICAL SPECIFICATIONS

Preliminary Work

A. Laying out and leveling

Prior to initiating construction, the Contractor and COR will define the outline of the components of the project in accordance with the project drawings and, if necessary, the construction levels to be achieved will be appointed.

Additionally, signals (B.M.) shall be placed on the main points to confirm location and levels of work. The signals shall be with paint at strategic points at the existing walls.

Before beginning the construction, the Contractor shall verify all data, as shown in the drawings, and correct them in case there are any divergences between the real dimensions of the building and the data of the drawings, in accordance with the COR.

The construction axes and levels shall be marked in the area in a safe manner. The marks should be the most precise, clear, safe and stable for the most important axes and elements.

To comply with these requirements, the Contractor shall provide an expert topographer, supported by precision equipment such as: total station, levels, measuring tape, etc. as required for the placement of milestones and layouts of the remodeling project.

B. Warning signals:

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.

Earthwork, Excavation and Backfilling

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

A. Leveling and clearing of land

This section refers to land modifications required for the execution of construction in accordance with the project drawings.

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.

B 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 to be performed in the places where specific concrete, exterior works are to 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 so that the base soil is loosened or removed.

If this happens, it will be considered as an “over excavation” that should be corrected by the contractor according to the project 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 such a way as to guarantee the stability of those buildings without causing any damage.

Excavation shall be protected against rain, landslides and other excavation. The Contractor shall protect the personnel executing the excavation 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.

The standards for the provisional shoring in excavations are the following:

a.- When assemblages and props are used, these are placed at intervals no greater than 2.50 meters, measuring the timber lengthwise, and should penetrate the land enough to withstand the push of the walls in the excavation.

b.- Metallic cribbing shall be used for excavations greater than 5.00 meters deep or when the lateral push on the excavation walls is great.

c.- Whenever the conditions of the land demand so or when the structural drawings states, the excavation walls will be protected with stakes or projected concrete. This will be subsequently refilled according to the requirements established for the filling process.

For piping placement in excavation, the filling will be laid as a first step to cover a height of at least 20 centimeters 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.

C. 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 compressor. The compression 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 granular selected 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.

D. Excavation in conglomerate stratums and rock

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 sledgehammers or other similar are absolutely necessary.

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

E. 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.

Excavating during the rainy season shall be prohibited.

When placing stone masonries, concrete structures, or any structure, the Contractor will ensure that water is not present in excavations, and that it will remain so until mortar and concrete have set.

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.

Excavation is forbidden during the rainy season. 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.

F. Excavation for foundations

This section refers to the depth of the excavation needed for foundations that will be lower than that marked for cleaning and leveling, down to the depth established by the structural drawings or by recommendation of COR. Excavation will be done in a fashion to satisfactorily build the structures. The excavation sides will be totally vertical, and the bottom will be clean, free of waste, and correctly leveled.

The foundation's base level may vary depending on the actual condition of the current terrain.

It should be considered the possibility of over-excavating a percentage for stabilizing the ground upon which the foundation will be laid.

In no case will machine excavation be performed to a depth so that the soil of the bottom is loosened or removed. The final material to be excavated must be removed by pickax and shovel to a depth of 50 centimeters, also known as “conforming the plinth or ditch bottom”.

If landslides or collapses due to the depth of excavations or inconsistency of soil happen, shoring shall be built to prevent further damages or accidents.

Ditches shall remain clean, and no work will be executed in them if waste, loose dirt, water, etc. are found. After casting the foundation and pouring the foundation, the gap caused by excavation shall be filled and compressed with the extracted soil until reaching the initial level.

This work shall meet the specifications detailed for “compacted backfilling with natural soil”.

Leftover material shall be removed or placed as filling if acceptable by COR.

The Contractor shall take all necessary precautions to prevent water from entering excavation sites awaiting concrete pours. However, if soil deterioration is caused by unforeseen circumstances, the Contractor will perform necessary studies and analyses of the soil to deepen excavation.

G. Removal of waste 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.

H. 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 D698-64Tspecifications 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.

The backfilling of rock placement shall be made with fragments of healthy, dense, and exposure-resistant rocks, with angle formation satisfactory to COR. The minimal size of the stones shall be 20 centimeters, and the maximum determined by the project, always protecting the structure.

H.01 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 compression 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.

H.02 Compacted backfilling with granular material

Compacted backfilling with granular material is defined as placing horizontal layers of sub-base to a 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 sheepsfoot 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 compression process shall be done according to the standards of the American

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

H.03 Compacted soil improvement with selected stone

If necessary, a process should be considered wherein the quality and stability of the soil are enhanced by the addition of selected stone and subsequent compaction, aiming to improve soil characteristics to increase load-bearing capacity and resistance if the design strength is not achieved. The bidder should account for the necessary laboratory tests and design. The selected stone is placed in layers over the existing soil and compacted to create a solid and stable base.

This helps prevent soil settlement and provides adequate support for the structures to be built upon it.

Concrete Structures

A. Materials For Concrete

A.1 Cement

Cement is any powder-like material that mixed with a liquid, forms a binding paste capable of hardening, in time, both under water as well as in free air and which serves to join solid bodies.

It must comply with the ASTM standards, specification C 150.

The Contractor shall provide adequate facilities for the storage and protection of the cement against humidity. Cement that for any reason is partially dried or has clods is unacceptable.

The Contractor will not use rejected cement or previously used bags of cement.

Portland Standard cement of national production will be used and should comply with ASTM specifications and be accepted by the corresponding entities. The use of foreign cements is acceptable in case national cement is unavailable, as long as these foreign cements comply with the same basic requirements. All cement shall comply with the regulation of the Honduran

Construction Code. The use of different brands of cements is not recommended at all when building one single structure or foundation.

The manufacturer might decide to add additives during the cement manufacturing process, which is acceptable if those materials, in the amounts to be used, meet the requirements of

ASTM standards.

The cement must be stored in a completely dry and ventilated place, under cover, and placed on wood pallets. No more than 14 bags of cement should be placed on top of each other, and the cement should not be stored for long periods of time.

If Portland cement has been stored in bulk for over 6 months or has been stored in bags for over 3 months, the cement should be sampled, tested, and must meet the appropriate requirements, before being used.

Cement shall meet the tests listed in the previous paragraph, and correspond to ASTM and

AASHTO standards:

TYPE OF TEST

• Chemical analysis

• Grain fineness

• Setting time

• Normal consistency

• Resistance to compression

• Resistance to flexion

• Resistance to pulling forces.

If the test results do not fulfill specified requirements, the cement will be rejected.

If there are several types of cement, these should be stored separately and correctly identified so that they are not mixed.

A.2 Gravel stone aggregates

Gravel stone aggregates for concrete will be made up of gravel, crushed rocks, or a combination of these, and shall meet the requirements of the American Concrete Institute ACI, AASHTO and ASTM standards.

Concrete will use mechanically ground rocks, from andesitic sources, preferably made out of blue rocks.

Gravel stones used for the manufacturing of any type of concrete shall be the product of mechanical grinding; the use of natural material extracted from a quarry is not allowed. This material shall preferably be blue stone and shall have passed through a 4 cm sieve, as specified in the ASTM standard.

The Contractor shall assure availability on the work site of the required quantity of gravel stone that will be used for mixing concrete, fills, filters, transition zones, drains, etc.

The Contractor shall use gravel without impurities, organic matter and other harmful elements.

It shall be thoroughly washed before use. Tile-shaped or long- shaped gravel is not allowed.

The thick aggregate that shall be used for concrete elaboration will consist of hard rock fragments with a diameter not less than 5 millimeters, dense and long-lasting, free of objectionable quantities of dust, soil, slates, alkalis, organic material, vegetable soil, mica and other harmful substances.

Round-shaped gravel that has been manually crushed or gravel from natural quarries, as long as it has a cubic or pyramidal shape, may be used. Gravel with over 15% of flat or long-shaped rocks will not be used.

The production and storage of gravel shall be done by dividing the gravel into three separate groups according to the maximum nominal size of the gravel and the following requirements:

SIEVE PERCENTAGE OF MASS PASSING SAUARE MESH SIEVES

(square openings) No.4 to 3/4"(19 mm) 3/4" to 1 ½ "(38mm) 1 ½ to 2" (76mm)

3" (76 mm) 90-100

2" (50 mm) 100 20 - 55

1 ½ " (38 mm) 90 - 100 0 - 10

1" (25 mm) 100 20 – 45 0 - 5

¾” (19mm) 90 - 100 0 - 10

3/8” (10mm) 30 – 55 0 - 5

No. 4 (4.8mm) 0 - 5

All components added to Portland cement concrete shall meet the requirements regarding particle size standards according to ASTM C136-06.

The ASTM standard requires particle sizing tests to verify their sizes. This will also be confirmed by the Contractor.

The specific gravity of particles shall be determined according to the testing method specified by the ASTM standard.

The following are the maximum allowable percentages (expressed as percentages of the sample weight) of foreign substances and determining factors of added components.

COARSELY GRAINED COMPONENTS % OF THE TOTAL WEIGHT

Firmness, sodium sulphate, losses after five cycles: 12.00

Abrasion – Los Angeles test (losses): 35.00

Material that passes through sieve number 200: 0.50

Clay: 0.25

Coal and lignite: 0.25

Soft or lightweight particles: 2.00

Other substances: 1.00

The amount of harmful substances in gravel stone shall not exceed the limits specified by the

ASTM standard for this component.

The use of premixed concrete produced by companies that have certificates proving the use of high-quality materials is recommended. Specifically, the company must support its decision to use certain materials based on their resistance, which cannot be lower than the one specified in the structural design.

A.3 Fine-Grained Sand

Fine-grained sand for concrete should be comprised of natural sand, sand from grinding processes (gravel), or a combination of both.

The sand should be clean, siliceous (quartz or granite sand), from mines or from other inert materials with similar characteristics. The sand should be made up of hard, angular, and rough grains, which should be strong and free from soft particles, organic material, shale, or slate.

Clayish, soft, or disintegrating sands must not be used. Likewise, finely grained sand with a humidity of over 8% must not be used.

The requirements regarding particle sizing should meet the ASTM standard, i.e. arid elements for concrete. Requirements: The fineness module should be less than 2.4 and greater than 3.1.

After the particle size has been established, the fineness of the sand module should remain stable, with variations of at most ± 0.2. Otherwise, the COR may decide that other combinations must be produced. If there are no satisfactory results, this material must be rejected.

The material shall meet the following tests:

The ASTM C136-06 standard specifies the particle sizing tests to be undertaken to verify their sizes.

The specific gravity of sand particles will be determined according to the testing method specified by the ASTM standard.

The weight per unit of sand particles will be determined according to the testing method specified by the ASTM standards for concrete.

The fine-grained arid component must not contain harmful or organic matter. To verify this, the testing method specified by the ASTM standard shall be used. If it is darker than the standard, it must be rejected.

Fine-grained sand that was rejected due to organic impurities can still be used if the discoloring is mainly caused by small amounts of coal, lignite, or similar discrete particles. It may also be accepted if, after running tests to determine the effect of organic impurities on the resistance of concrete, the relative resistance, after a seven-day period, according to the ASTM standard, is not lower than 95%.

Fine-grained sand to be used in concrete that will be exposed to water, to prolonged exposure to environmental humidity, or contact with soil humidity should not have materials that might react adversely to the alkali of cement and whose amounts are such that an excessive expansion of concrete might take place. If these materials are present in harmful amounts, fine-grain sand can be used, provided that the cement will have less than 0.6% alkali estimated based on the amount of sodium oxide.

Fine-grain sand submitted to 5 immersive and drying cycles for the test to measure the resistance to disintegration (the ASTM standard) must have a mass loss of less than 10% if sodium sulphate is used and less than 15% if magnesium sulphate is used. Finely grained sand that does not meet these standards may be used provided that concrete with similar features, made from similar sand from the same source, has produced satisfactory results when exposed to similar weather conditions to the ones to which the concrete with those characteristics will be exposed.

All fine-grain sand used for tests shall meet the sampling requirements established by the

ASTM standard. The amount of harmful substances in fine-grain sand shall not exceed the limits specified by the ASTM standard.

The following are the maximum allowable percentages (expressed as percentages of the sample weight) of foreign substances and determining factors of added components.

FINELY GRAINED SAND % OF THE TOTAL WEIGHT

Material that passes through sieve number 200 3.00

Clays and disintegrating particles 0.50

Coal and lignite 0.25

Other harmful substances 2.00

Maximum allowable total 4.00

The amount of harmful substances in fine-grained sand shall not exceed the limits specified by norms ASTM standard for fine-grained sand.

A.4 Large stones for cyclopean concrete (rip-rap concrete)

The large stone for cyclopean concrete shall come from quarries or collection banks that must be clean, granitoid or sandstone. Stones of between 10cm to 25cm in diameter shall be used for this type of concrete. The stone shall not exceed more than 50% of the concrete component.

The stone will be solid, resistant and long-lasting, free of organic matter or clay residues. It will be homogeneous, with uniform color and will be free of cracking or crevices (clear sound to hammering), or other flaws that would reduce its strength.

Any weathered stone (affected by meteoric phenomena) must be rejected. It must have a density equal to or greater than 12% on durability assays.

The size of the stones shall not surpass 25% of the smallest dimension on the structure to be built. It is unacceptable to indicate that humidity reduces the strength, and for that reason porous stone assays shall be done by saturation and without localized efflorescence.

The COR has the right to demand from the Constructor the results of tests and assays used to verify the good condition and quality of the aggregate, taking into consideration the norms specified by ASTM for this particular case:

• Coarse arid materials for concrete. Determines the abrasion value of the coarse arid material for particles greater than 19 mm, using the angel’s machine.

• Arid materials for concrete. Determines strength to disintegration.

Transportation will be in bulk and precautionary measures will be taken so that during loading and unloading deterioration is not caused by touching one against the other. Covered storage is not necessary, but the Contractor must ensure that the material will not become saturated with dust and other material that can lower its strength.

A.5 Types of concrete

This section consists of all the necessary materials, equipment and labor to make plain concrete.

Concrete is the hardened product resulting from the mix of the Portland cement, water, and stony aggregates in adequate proportions. It can contain additives to provide it with specific or special properties.

Cyclopean Concrete (Rip-rap):

Cyclopean concrete shall be constructed with a mixture of a 60% plain concrete and 40% large stones (variable size between 10 and 25 centimeters). The plain concrete to be used in this job shall have a minimum resistance of 180 kg/cm² on the 28th day and the materials should be saturated before creating the mixture. Stony materials will comply with the ASTM standard and dosage will be according to concrete design.

In the first step, the contractor shall apply a plain concrete layer of 15-centimeter depth and subsequently a layer of stone shall be placed manually on top. The spaces between the stones will not be less than 5 centimeters in any of the rows and from structure edges. The next step is to place another layer of plain concrete and the same procedure is followed until the desired height is reached.

The dosage varies in accordance with the structure needs described in the respective drawings.

Plain Concrete:

Plain concrete results from mixing coarse, arid materials of up to 5 cm. in diameter (nominal) and fine, arid materials joined by a paste of water and cement (see specification for “gravel stone aggregate” and “fine-grained sand”).

To obtain good, uniform, strong, long-lasting, and cheap concrete, the following items should be closely monitored:

• Material quality

• Dosage of components

• Management, placing and concrete setting.

The proportion of water and cement must be tested for appropriate dosage and should include the following data points:

• Degree of humidity of aggregates

• Climate of the work area

• Use of additives

• Conditions for concrete exposure; and

• Thickness and type of planking

The dosage of plain concrete varies in accordance with the type of work that it’s going to be used on:

DOSIFICATION

STRENGHT

USE

Kg/cm²

1:3:6 180

Concrete thick walls of larger thickness, pavements, first concrete layers, floors, and anchors for pipes.

1:2:4 210

Non-voluminous walls and jobs of reinforced concrete in general. (retaining walls)

1:1.5:4 280 Hydraulic jobs in general

Another factor that has influence in concrete design and its final quality is the water-cement ratio, which has to be as low as possible, so that concrete always has the conditions of impermeability, handling and workability in accordance with each purpose.

Another factor influencing the concrete design given materials and conditions of curing, the quality of the concrete as closely as possible to its final concrete mix is low water cement ratio, in accordance with its purpose.

STRONG TO:

CONCRETE WITHOUT AIR

INCORPORATOR

CONCRETE WITH AIR

INCORPORATOR

THE SPECIFIED

COMPRESSION

f'c (Kg/cm²)

ABSOLUTE

RELATION

BY WEIGHT

LITERS PER

BAG OF

CEMENT

ABSOLUTE

RELATION

BY WEIGHT

LITERS PER

BAG OF

CEMENT

175 0.65 32.40 0.54 37.00

210 0.58 29.30 0.46 23.00

245 0.51 25.70 0.40 20.00

280 0.44 22.20 0.35 17.70

315 0.38 19.10 0.30 15.10

350 0.31 15.10 ** **

Strength at 28th day for the cement to meet the strength limits of the ASTM regulations norm, Type I, IA, II or IIA; and strength at 7 days for cements Type III o IIIA.

With the majority of the materials, the given water-cement ratio, provides average strength higher than the indicated.

** The concrete mix dosage for strength greater than 300 Kg/cm² with air incorporator.

The concrete shall be mix by mechanical vibration, except for small amounts (less than 100

kg) that can be made by hand. The dosage will be made by weight, using a platform scale that allows putting a wheelbarrow of aggregate on it.

The concrete prepared in a mechanical vibration will be mixed at least for the time indicated in the following table:

CAPACITY OF THE CONCRETE MIXER MIXING TIME

m3 Min

0 - 1.50 1.5

1.50 - 2.30 2

2.30 - 3.00 2.5

3.00 - 3.80 3.75

3.80 - 4.00

The machine will give at least 60 revolutions in the indicated times.

Concrete will be discharged completely before the mixer will be loaded again. The mixer will have to be cleaned up at regular intervals while being used and will have good mechanical maintenance.

When the concrete is mixed by hand; the sand and the cement will be mixed in a dry basis until it gets a uniform color. The rubble or split stone will be extended in a platform of wood or metal forming a layer of uniform width, adding humidity and then adding the dry mortar. The mix will be mixed with shovel. until it becomes completely homogeneous.

Under normal conditions of operation. the changes in the consistence as indicated in the settlement test will be used as indicators of change in the characteristics of the materials. the ratios or the water content. To avoid mixes too dense or too fluid. the settlement tests shall follow the following guidelines stated in the chart below:

TYPE OF CONSTRUCTION SLUMP (mm)

MAXIMUM MINIMUM

Concrete foundations. walls and plinths 127 50

Plinths without framework. melting boxes and walls over structures.

100 25

Slab stones. beams and concrete walls 152 76

Pillars for buildings 152 76

Pavements 76 50

Construction of heavy masses 76 25

The setting tests will be done before the placement of concrete additives.

When concrete does not reach the strength for compression (cracking load) for which it was designed within 28 days it will be necessary to improve the quality of the aggregates or to create a new design in a material strength test lab.

Test for concrete:

Consistence tests will be made in the first stops until the outflow conditions of the mix are stabilized. In case that there will be changes in the humidity conditions of the aggregates or weather changes. if the process of transportation from the cement mixer to the foundation site is too long. or is subject to considerable evaporation. field testing shall be performed. The tests will have to be done with the required frequency.

➢ The compression strength tests will be done based in the ASTM specifications for cylindrical molds.

➢ In order to assess compliance of concrete during construction. the Contractor shall prepare and cure test specimens which shall be tested at 7 days. 14 days and 28 days as determined by the Engineer. or at any other interval that may be deemed necessary to determine the strength of concrete

The result is valid when several tests and an average of the series of tested cylinders has been taken. which cannot be distorted or defective.

➢ When the average of results of the cylinders is taken in a day. tested for seven days and it does not meet 80% of the compressive strength. an additional drying period for a maximum lapse of 14 days will be ordered; structure tests will be required by command.

➢ Once tests are made and it is determined that that concrete does not meet the specified quality. structure must be reinforced, or it shall be replaced either totally or partially in accordance with the case. then proceed to create a new design for the next structures.

Transportation and handling

Concrete will be transported from the concrete mixer to the site. using methods that prevent or reduce to a minimum separation and material loses. The equipment should be of an appropriate design and size to assure concrete flow at the delivery site.

Discharge trucks (mixer) will have to avoid the segregation of components. their surface will have to be smooth (preferable metal) to avoid filtering and overflows.

Concrete will not be located at heights greater than one meter above the plank molding or foundation bottom. when required to drain the concrete from a major height; special devices to prevent segregation will be used.

A.6 Additives

Additives will be used on concrete to improve one or several of its qualities. as well as others:

➢ Improving workability

➢ Reducing material segregation

➢ Air incorporation

➢ Acceleration of the drying process

➢ Retard the drying process.

➢ Waterproofing

➢ Thickening of concrete

In any case, the use of different additives will be done with the prior authorization from COR, and observing the dosage recommendations from manufacturer. Additives for concrete shall be from recognized manufacturers that meet all the standards set for by ASTM for Chemical additives and air reducing additives for Concrete.

Water reducing, retarding, and accelerating additives must comply with the "Specifications for

Chemical Additives for Concrete" (ASTM–C–490) and all other requirements described in it.

except the infrared analysis.

A.7 Formwork

It will be understood as formworks the volumetric shapes which are made with pieces of wood.

metal or any other resistant material. so as to support the emptying of concrete. in order to mold it to the foreseen shape.

The formworks generally built in wood, shall be sufficiently strong to resist the pressure.

resulting from the emptying and vibration of concrete. to be rigidly supported in their correct position and sufficiently waterproof as to avoid the loss of slurry.

To build the different concrete sections, contractor shall use metallic or timber formworks according to the measures that are detailed in the structural drawings. The design and engineering of the formwork as well as its construction shall be the responsibility of the

Contractor.

Formwork design shall be submitted to the COR prior to the first concrete placement.

Forms shall be properly aligned. adequately supported. and tight. The form surface shall be smooth and free from irregularities. dents. sags. or holes when used for permanently exposed faces. All exposed joints and edges shall be chamfered. unless otherwise indicated.

Forms for exposed surfaces shall be coated with a non-staining form oil. which shall be applied shortly before concrete is placed.

Formworks shall not be removed before the expiration of 24 hours after concrete placement except where otherwise specifically authorized. Also. in the case of concrete slabs. the formworks shall not be removed before the expiration of 21 days after concrete placement.

except if contractor has used additives for its construction and has verified the appropriate concrete’s resistance trough a concrete test. Supporting forms and shoring shall not be removed until the concrete has cured for at least 5 days. When conditions on the work are such as to justify the requirement. forms will be required to remain in place for longer periods.

A.8 Curing Materials

Beginning immediately after placement and continuing for at least 7 days. all concrete shall be cured and protected from premature drying. extremes in temperature. rapid temperature change. freezing. mechanical damage. and exposure to rain or flowing water. All materials and equipment needed for adequate curing and protection shall be available and at the site of the placement prior to the start of the concrete placement. Preservation of moisture for concrete surfaces not in contact with forms shall be accomplished by one of the following methods:

Continuous sprinkling or ponding.

Application of absorptive mats or fabrics kept continuously wet.

Application of sand kept continuously wet.

Application of impervious sheet materials. ASTM C 171.

Application of membrane-forming curing compound. ASTM C 309. type –D or 2. Class A.

If formworks area removed prior to the end of the required curing period. other curing methods shall be used for the balance of the curing period. During the period of protection removal, the temperature of the air in contact with the concrete shall not be allowed to drop more than 15 degrees C within a 24-hour period.

A.9 WATER

The water to be used to make the concrete shall be potable. and shall not have organic or poisonous materials or oils. or harmful substances such as acids and salts. The water shall meet the requirements of the Honduran Construction Code. Potable water: Requirements. The water to be used to cure concrete shall meet the same requirements of the water used for mixing.

B. Concrete Specifications

B.1 First Concrete Layer for Structures (f’c = 180 Kg/cm²)

The first layer of plain concrete generally has low strength (minimum f’c = 180 Kg/cm²). except for those that specify the opposite according to the structural design. and in the respective drawings. The first concrete layer is used as the support base of structural elements and/or pipes that do not need the plank molding. In accordance with the specifications indicated in the structural working drawings or COR's approval.

The surface. on which the first concrete layer will be placed. will have to be totally leveled. dry and free of foreign material that can cause detriment to the element characteristics. Placement of concrete had to be done with the thickness specified in the working drawings and poured from a height not greater than one meter.

Contractor shall do permanent checkups in accordance with the work plan. or the schedule for concrete.

When pre-mixed concrete is required. supplier shall be informed of the required specifications prior to purchase and COR will verify the conditions of concrete at delivery time.

To confirm the quality of the concrete. the Contractor shall perform all the requirements described above under “test for concrete”. Also, if the COR’s requires additional tests to verify the concrete quality. this shall be performed by the Contractor without any additional cost to the contract.

B.2 Concrete for Foundations (f’c = 210 Kg/cm²)

Concrete for foundations shall have a determined strength (f’c = 210 Kg/cm²) that is used for plinths. shoe soles, slabs or foundation beams specified in the structural working drawings.

forming the structural base of the project. It includes the processes of manufacturing. draining.

and setting of concrete.

Manufacturing of plain concrete shall be at the work site with strength of 210 Kg/cm². and shall be controlled for optimum quality by the contractor.

It shall be placed in layers of a thickness that may facilitate its handling. adequate vibration and the concrete compacting while being poured.

The correct positioning and leveling of reinforcing steel at the moment of pouring the concrete shall be cautious. when mechanical compression continues while concrete areas are being completed. leveling with metal or wooden shore props.

In cases such as this. the lateral plank molding shall be removed. considering the drying time of the concrete. to prevent detachment of edges in plinths and/or beams in accordance with the case. If these situations occurred. immediate repair shall be executed using mortar with similar characteristics to that concrete used and with the necessary additives to insure repair.

For each case of concrete foundation, the Contractor shall have to develop permanent checkouts in accordance with the job’s planning. or the concrete work schedule.

If pre-mixed concrete would be used. supplier shall be informed of the required specifications prior to purchase and conjointly with COR shall verify the conditions of concrete at delivery time. at job site.

described above under “test for concrete”. Also. if the COR requires additional test to verify the concrete quality. this shall be performed by the Contractor without any additional cost to the contract.

B.4 Concrete for Columns or Pedestals (f’c = 210 Kg/cm²)

This item consists of providing all the necessary materials. equipment and labor. to elaborate.

pour and dry concrete (210 kg/cm2) for pillars and columns as indicated on the structural working drawings.

Manufacturing of plain concrete shall be at the work site with strength of 210 Kg/cm². and shall be controlled by the contractor to be optimum.

It shall be placed in layers of thickness that may facilitate its handling. adequate vibration and the concrete compacting while being poured.

When premixed concrete the following is necessary. equipment shall be used as required and necessary for the execution of the concrete casting of any strength or any load. premixed concrete shall be used and delivered at the job site by concrete distribution trucks.

Contractor shall do permanent checkups in accordance with the work plan. or schedule.

When premixed concrete is required. supplier will inform of the required specifications prior to purchase and COR will verify the conditions of concrete at delivery time.

Steel reinforcement will be folded and in accordance with the structural working drawings. The main support of the columns will be embedded from plinths. and will prop to the height of the subsequent sub-floor. The vertical clamps will always prop up from the main support. It shall be placed at distances established in the working drawings. without interrupting its lacing on the intersection beams.

Once the reinforcement steel is armed. the formwork shall be set. It shall meet the shape.

alignment and dimensions of the structural elements. The formworks shall be reinforced or tied with eucalyptus wood of the area. or metal. in such a way that they preserve their shape and position.

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