The Second Longest Suspension Bridge of Nepal

Building Financial advisors

Construction projects can suffer from preventable financial problems. Underbids ask for too little money to complete the project. Cash flow problems exist when the present amount of funding cannot cover the current costs for labour and materials, and because they are a matter of having sufficient funds at a specific time, can arise even when the overall total is enough. Fraud is a problem in many fields, but is notoriously prevalent in the construction field[citation needed]. Financial planning for the project is intended to ensure that a solid plan with adequate safeguards and contingency plans are in place before the project is started and is required to ensure that the plan is properly executed over the life of the project.

Mortgage bankers, accountants, and cost engineers are likely participants in creating an overall plan for the financial management of the building construction project. The presence of the mortgage banker is highly likely, even in relatively small projects since the owner's equity in the property is the most obvious source of funding for a building project. Accountants act to study the expected monetary flow over the life of the project and to monitor the payouts throughout the process. Cost engineers apply expertise to relate the work and materials involved to a proper valuation. Cost overruns with government projects have occurred when the contractor was able to identify change orders or changes in the project resulting in large increases in cost, which are not subject to competition by other firm as they have already been eliminated from consideration after the initial bid.[1]
Large projects can involve highly complex financial plans. As portions of a project are completed, they may be sold, supplanting one lender or owner for another, while the logistical requirements of having the right trades and materials available for each stage of the building construction project carries forward. In many English-speaking countries, but not the United States, projects typically use quantity surveyors.

Building Construction Processes

Design team
Shasta Dam under construction in June 1942

In the modern industrialized world, construction usually involves the translation of designs into reality. A formal design team may be assembled to plan the physical proceedings, and to integrate those proceedings with the other parts. The design usually consists of drawings and specifications, usually prepared by a design team including surveyors, civil engineers, cost engineers (or quantity surveyors), mechanical engineers, electrical engineers, structural engineers and fire protection engineers. The design team is most commonly employed by (i.e. in contract with) the property owner. Under this system, once the design is completed by the design team, a number of construction companies or construction management companies may then be asked to make a bid for the work, either based directly on the design, or on the basis of drawings and a bill of quantities provided by a quantity surveyor. Following evaluation of bids, the owner will typically award a contract to the most cost efficient bidder.
The modern trend in design is toward integration of previously separated specialties, especially among large firms. In the past, architects, interior designers, engineers, developers, construction managers, and general contractors were more likely to be entirely separate companies, even in the larger firms. Presently, a firm that is nominally an "architecture" or "construction management" firm may have experts from all related fields as employees, or to have an associated company that provides each necessary skill. Thus, each such firm may offer itself as "one-stop shopping" for a construction project, from beginning to end. This is designated as a "design Build" contract where the contractor is given a performance specification and must undertake the project from design to construction, while adhering to the performance specifications.
Several project structures can assist the owner in this integration, including design-build, partnering and construction management. In general, each of these project structures allows the owner to integrate the services of architects, interior designers, engineers and constructors throughout design and construction. In response, many companies are growing beyond traditional offerings of design or construction services alone and are placing more emphasis on establishing relationships with other necessary participants through the design-build process.
The increasing complexity of construction projects creates the need for design professionals trained in all phases of the project's life-cycle and develop an appreciation of the building as an advanced technological system requiring close integration of many sub-systems and their individual components, including sustainability. Building engineering is an emerging discipline that attempts to meet this new challenge.

Building Construction Processes

Building construction is the process of adding structure to real property. The vast majority of building construction projects are small renovations, such as addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster, and design team for the entire project. However, all building construction projects include some elements in common - design, financial, and legal considerations. Many projects of varying sizes reach undesirable end results, such as structural collapse, cost overruns, and/or litigation reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome.

Building construction is procured privately or publicly utilizing various delivery methodologies, including hard bid, negotiated price, traditional, management contracting, construction management-at-risk, design & build and design-build bridging.
Residential construction practices, technologies, and resources must conform to local building authority regulations and codes of practice. Materials readily available in the area generally dictate the construction materials used (e.g. brick versus stone, versus timber). Cost of construction on a per square metre (or per square foot) basis for houses can vary dramatically based on site conditions, local regulations, economies of scale (custom designed homes are always more expensive to build) and the availability of skilled tradespeople. As residential (as well as all other types of construction) can generate a lot of waste, careful planning again is needed here.
The most popular method of residential construction in the United States is wood framed construction. As efficiency codes have come into effect in recent years, new construction technologies and methods have emerged. University Construction Management departments are on the cutting edge of the newest methods of construction intended to improve efficiency, performance and reduce construction waste.

Timber or Steel Prefabricated Frame

Once the floor structure is in place the walls are erected directly on top of the chipboard or slab. Walls act as a loading bearing support for the roof and provide space for openings such as doors and windows, and they enclose the house and seal it from weather. Walls comprise of either a structural frame and cladding or solid masonry.
This is the most common type of house wall framing.
Steel itself is more termite resistant than timber however timber is more forgiving and accommodates alterations more easily. Timber framing can be pre-treated for termite prevention however the chemicals do weaken in time.
This type of frame is usually pre-made to order. It consists of:

• Plates (horizontal top and bottom members)
• Studs (vertical members between the plates)
• Noggins (additional horizontal members between studs)
• Galvanised strap bracing is added diagonally to brace the frame and stop racking.

Metal angle bracing is essential for structural integrity in walls (as it is for pier areas, floors, and roofs).
Openings in wall frames require a timber, steel or lightweight aluminium overhead beam called a Lintel. Steel frames and load bearing brick walls, although termite resistant, do not accommodate changes easily. Also be aware if you are cutting holes in the framework to accomodate kicthen and bathroom conduit that you will need to follow the latest Australian standard to insure that the framework remains structurally sound.

Post and Beam

Post and Beam can be steel or timber. It is used when building elements are to be exposed. Post and beam construction is assembled on site and is in-filled with a timber frame. This method requires more precision and is more labour intensive but can look very good. Often laminated beams of sheets of timber glued together under pressure called "HySpan" (http://www.dindaslew.com.au/?id=7) are used. They are very strong, straight and never warp.

Solid Masonry

This includes double brick, core filled concrete block work and natural stone and mud-brick as both a load bearing structure and an outside cladding surface to seal out weather.
With double brick construction both layers of wall are load bearing, all plumbing and lighting conduit should be cattered for during the initial construction period. Altering masonry or brickwork for bathroom and kitchen conduit after this time is labour intensive.
Windows and doors need steel or concrete lintels to support masonry above. In some cases the exterior brick is rendered, bagged or painted. (Click here to read more about Cement Rendering, or go to the Toptex website to learn about their lightweight smart brick and solid plastering services).
All masonry walls require damp proofing to stop rising damp creeping up surfaces.
All single skin external walls such as sandstone, core filled concrete block work and mud brick will require a large roof overhang or surface waterproofing to prevent water penetration and or mould build-up.

Footings & Floor Construction

The type of footings used for a new home will be suggested by the home designer with possible consultation with a geo-tech consultant. The factors that influence the type of footings are:

• Weight of building
• Wall construction type and height
• Soil type
• Slope of the block
• Budget
• Drainage requirements on the block

There are five main types of footings:

Strip Footings

A Strip Footing is a relatively small strip of concrete placed into a trench and reinforced with steel. The footing supports the load of the exterior walls and any interior wall that is load bearing or supports a slab such as for a bathroom. Strip footings can be used for both traditional timber and concrete floors. They are one of the most common footing used in Australia.

Concrete pad footings.

A concrete pad footing is the simplest and cost effective footing used for the vertical support and the transfer of building loads to the ground. These footings are "isolated" ie there is no connection between them. They are also reinforced.
Holes are dug (say 400mm wide x 400mm deep) into the ground and fitted with a reinforcement cage then filed in with a concrete mix to ground level.
Concrete pad footings are used to support light weight timber-framed houses.

Pole Construction (Post and Concrete)

For this type of footing a hole is dug into the ground about 800mm wide x 1600mm deep. A pole is then placed into the hole and ready mixed concrete is back filled around the pole. Pole construction footings do not require steel reinforcement (or an engineer) and are therefore also one of the least expensive footings types.
Pole Construction is the most economical way of constructing a pier/footing on sloping land but engineer's details will be required for the builder and certifying authorities. A few essential considerations are:

1. How long the poles will need to be and the spacing?
2. What will be the correct height of all poles?
3. How far down will the pole will need to penetrate?
4. How will the concrete around the pole need to be finished to reduce wood rot?
5. What will the diameter of the poles need to be?
6. What are the poles are made of (steel or timber)?

Grout Injected Piles

Where it is impossible for a footing to be constructed, a pile which is both pier and footing is used.
This method is only used in unstable or potentially unstable soils such as mud flat estuary areas and beach front etc. Grout injected piles are "isolated" footings and/or piers, which are cement grouted (not concrete) and steel reinforced, with an overall diameter of around 600mm.
The piers are installed by inserting a cork like screw (Metal Auger) attached to a Backhoe in to the ground. The Auger screws all the dirt out of the pier hole that will be around 6 meters in depth. Once all the dirt is removed the grout is injected through the end of the rotating Auger into the hole. As the hole fills with grout the rotating Auger is slowly removed ensuring no dirt collapses back into the hole. The Auger machine drills out the pier holes with minimal disturbance to adjoining soil and structures. Mini piles use the same process and materials as grout injected piles but are around 200mm in diameter

Timber Piles

Timbers piles are a more cost affective method of constructing structural piles. Timber piles are long timber poles around 6000mm in length and 400mm in diameter that are hammered deep into the ground by a pile driving rig (big hammer). The piles are driven into the ground their full length or until the pile hits bedrock. If the pile hits a floating bolder it will skew in the ground but the pile will be amply stable to support a floor structure. Pile driving vibration can disturb adjacent buildings, resulting in cracking, failure and even collapse.

History

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Quite naturally, early dam builders began by using plentiful materials like sand, timber and brush, and gravel. Their construction method consisted of carrying the materials by the basketful and loosely dumping the fill, so many of these dams may have survived only a few years. Scientists have not been able to pinpoint dates for the earliest dam construction, but they do know dams were needed where food was grown and in areas prone to flooding.

Design of fill dams is based on experience; while failures are unfortunate and sometimes catastrophic, they are also the best teachers, and many engineering advances have been founded on careful study of earlier failures. The engineers of ancient India and Sri Lanka were the most successful pioneers of fill dam design and construction, and remains of earth dams can still be seen in both countries. In Sri Lanka, long embankments called tanks were built to store irrigation water. The Kalabalala Tank was 37 mi (60 km) long around its perimeter.
The most famous earth fill dam recently constructed is the Aswan High Dam that was built across the Nile River in Egypt in 1970-1980. An earth fill dam was also the victim of a spectacular failure in June 1976 when the Teton Dam in Idaho eroded from within due to incorrect design of the zones inside the dam that allowed seepage, failure, and flooding of the valley downstream. Although earth dams tend to be short and broad, Nurek Dam in Tajikistan is 984 ft (300 m) high.


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Raw Materials

The materials used to construct fill dams include soil and rock. Soil is classified by particle size from the smallest, submicroscopic particles called clay; silt, which is also very fine; sand ranging from fine to coarse, where the fine grains are the smallest soil particles our eyes can see; and gravel. Coarser fragments called cobbles and boulders are also used in dam construction but usually as protective outer layers.
Specific soil types and size ranges are needed to construct the zones within the dam, and explorations of the dam foundation area, the reservoir where the water will be stored, and surrounding areas are performed not only for design of the dam but to locate construction materials. The costs of fill construction rise dramatically with the distance materials are hauled. Samples of potential construction materials are tested in a soil laboratory for grain size, moisture content, dry density (weight), plasticity, and permeability. Clay is not only very fine in size but has chemical characteristics that cause it to stick together. The combination of fine size and plastic behavior also causes the clay to be less permeable to water. If clay is available near the site, the dam can be built with an impermeable core or central zone that prevents water from passing through the dam; otherwise, the dam must be designed so water can seep slowly and safely through a different combination of materials in its zones.
Water is also a raw material. The various soil types have compaction characteristics that can be determined in the laboratory and used during construction. Soil can be compacted to its best functional density by adding moisture and weight and impact, called compactive effort. Large vibrating rollers press thin layers of soil into place after an optimal amount of water has been added. The water and weight bond the soil particles together and force smaller particles into spaces between larger particles so voids are eliminated or made as small as possible to restrict seepage.
Increasingly, fill dams also include geotextiles and geomembranes. Geotextiles are nonwoven fabrics that are strong and puncture-resistant. They can be placed between lifts as the dam is raised to strength weak materials. They are also used as filter fabrics to wrap coarser drain rock and limit the migration of fine soil into the drainage material. Geomembranes are made of high-density polyethylene (HDPE) plastic and are impermeable. They can be used to line the upstream face of a fill dam or even to line the entire reservoir.


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BIG DAMS

The world's two tallest dams are located in Tajikistan in the city of Vakhsh where they tower over 335 meters, or 1,100 feet tall (Rogun) and 300 meters, or 985 feet tall (Nurek). The Three Gorges Dam in China, a concrete gravity dam scheduled for completion in 2009, will be 175 meters tall (574 feet), the equivalent of a 48-story building.

When completed, Three Gorges Dam will be the world's largest hydropower facility with a generation capacity of 18,200 megawatts. It will simultaneously supply flood storage and enhance navigation along the Yangtze River. The structure will create a reservoir more than 600 kilometers long and 1,100 meters wide, capable of storing 39.3 billion cubic meters of water.
Construction of the dam, which began in 1993, requires the inundation of 632 square kilometers of existing land and will cause the permanent relocation of over 1.2 million people.


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Quality Control For Dam Construction

Quality engineering is essential in the construction of a fill dam because the materials used have lower strength properties than the steel and concrete required for concrete dams and because placement ultimately determine strength, potential for problems like seepage and settlement, and finally performance and safety. The geotechnical project engineer occupies the key role of making sure the design and earth materials match to make a safe product; but many other professionals including geologists, construction technicians, other engineers, and the representatives of overseeing agencies are fully committed to the same purpose.

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The Dam Construction Process

Fill dams are constructed in the dry season when water levels in the river or stream are lower, rainfall on sources of fill material is less likely, and conditions are better for operating large construction equipment. Before construction actually begins, the site is surveyed to locate the dam alignment on the existing ground, the areas that will be excavated, and the borrow areas or sources for the soil or rock used in construction. Construction management facilities are set up; usually, the construction manager (a field engineer with years of similar experience) will work out of a trailer on site. Depending on the site, it may be necessary to install instruments to monitor the effects of dam construction on adjacent hillsides or other features and to measure groundwater levels throughout construction in the foundation and surroundings. And, of course, the flow of the stream that is being dammed through the site must be stopped. This can be done by a variety of methods including diverting the stream, perhaps to flow through a neighboring channel, or stopping it upstream with a temporary dam or cofferdam.

Before construction of the dam begins, the foundation area must be prepared. In rare cases, dams can be constructed directly on the existing materials in the channel floor; at most sites, these materials are compressible (and would cause the dam to settle irregularly) and permeable (allowing water to pass under the dam). The foundation area also includes the abutments, which are the hillsides forming the two ends of the dam. Soil and soft or highly fractured rock are excavated, sorted by type, and stockpiled for later use in dam construction. The surface of the foundation bedrock is cleaned to a surprising degree; it is broomed and hosed with water so that any voids or irregularities are visible and cleaned of soft soil. The foundation is carefully inspected before any construction work; additional exploratory drilling may be done if there are any questions about the foundation's condition. If the rock is fractured or contains voids or holes, these are sealed with cement grout that is injected through small diameter drill holes in a process called dental work.

The base of the dam must go down into the ground before it rises above it. A trench that is the full width of the dam (across the channel) is cut into firm rock. The trench is called a keyway or cutoff wall and may have several benches or notches into rock. It prevents the dam from sliding along a smooth foundation and also creates a longer path for any seepage to try to flow under the dam. The impervious clay that will make up the core of the dam is placed in the keyway and compacted and raised, layer by layer, until the top of the keyway or base of the majority of the foundation is reached.

1. The soil in the keyway and all the zones of the dam are raised to the same levels at the same time. Ramps may have to be cut into the keyway area for the construction equipment, and then they must be built up to the working surface of the rising top of the dam. Whenever possible, roads are cut in from the two sides (abutments) of the dam for the easiest access; eventually, an access road will be built on the crest of the dam and extending onto these abutments. Large earthmovers haul the specific type of soil needed to raise the zone of the dam they are working on. The soil is spread in thin layers, usually 6-8 in (15.2-20.3 cm) thick, sprayed with water to the correct moisture content, and compacted with sheepsfoot rollers (compactive rollers with prongs resembling animal hooves mounted in rows around the roller that press and vibrate the soil firmly in place). If gravel is used in construction, a vibrating roller is used to vibrate the grains together so their angles intermesh and leave no openings.
   Throughout the compaction process, inspectors approve the soil that is hauled on site and hauled to the particular zone of the dam. They reject material that is contaminated with grasses, roots, trash, or other debris; and they also reject soil that does not appear to be the proper grain size for that zone of the dam. For quality control, samples are collected and tested in the laboratory (for large dams, an on-site soil lab is installed in a construction trailer) for a variety of classification tests. Meanwhile, the inspector uses a nuclear density gauge to test the soil for density and moisture content when it has been placed and compacted. The nuclear density gauge uses a very tiny radioactive source to emit radioactive particles into the soil; the particles bounce back onto a detector plate and indicate the moisture and density of the soil in place. The process is not harmful to the environment or the operator (who wears a badge to monitor radioactive exposure) and provides data without having to excavate and sample. If the compaction requirements are not met, that layer of soil is excavated, placed again, and recompacted until its moisture and density are suitable.
   Construction of the fill dam proceeds layer by layer and zone by zone until the height of each zone and, eventually, the crest of the dam are reached. If the entire dam cannot be built in one construction season, the dam is usually designed in phases or stages. Completing a construction stage (or the entire dam) is often a race against time, the weather, and the project budget.
2. Some earth dams have instruments installed in them at the same time as fill placement is done, and the instruments are constructed to the surface in layers and zones, just like the fill. The condition of the dam is monitored throughout its lifetime, as required by federal, state, and local laws and by standards of engineering practice. Types of instruments vary depending on the location of the dam; almost all dams have settlement monuments that are surveyed to measure any settlement in the surface or zones of the dam, slope indicators to show if the sloping faces inside or on the surface of the dam are moving, and water-level indicators to monitor the water level in the dam's zones. Dams in seismically active areas may also be equipped with instruments to measure ground shaking.
3. Fill dams may have a variety of other facilities, depending on their, size, use, and location. An emergency spillway is required at all dams to allow for flood waters to flow over an escape route, rather than over the top of the dam. Other spillways for production of hydroelectric power may be designed and constructed at power-generating dams, and inlet and outlet tunnels are needed to release water for irrigation and drinking-water supplies at embankments built for those purposes. At fill dams, it is usually desirable to place these other facilities in excavations through the foundation or abutment rock; the process of compacting earth against structures that actually pass through the fill is tricky and allows for seepage paths.
4. Sometimes the reservoir area is also cleared when it is to be filled with water, particularly if lumber can be harvested. It is not necessary (and it is much too expensive) to clear it of all shrubs and grass. The process of filling the reservoir is relatively slow, so most wildlife will move as the water level rises; areas of concern include habitats for rare or endangered species, and drowning of these habitats has been a concern in the construction of a number of dams.

When the dam is complete, the water that was diverted from the stream channel is allowed to fill the reservoir. As the water rises, it is also rising in portions of the dam, and instruments within the dam are monitored carefully during the reservoir-filling period. Monitoring of the dam's performance, both by instruments and simple observation, is performed routinely; and safety plans are filed with local emergency services so that sudden changes in instrument readings or the appearance of the dam or its reservoir triggers actions to alert and evacuate persons living in the path of flood waters downstream. Repairs are also performed routinely.


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Overview of Dam-Building

The first dam for which reliable records exist was built on the Nile River sometime before 4000 B.C.E. near the ancient city of Memphis. Remains of other historic dams have been located at numerous sites bordering the Mediterranean Sea and throughout the Middle East, China, and Central America. The oldest continuously operating dam still in use is the Kofini Dam, which was constructed in 1260 B.C.E. on the Lakissa River in Greece.
Today, there are approximately 850,000 dams located around the world. Of the more than 40,000 that are categorized as large dams, more than half are located in China and India. It is estimated that 24 countries currently generate more than 90 percent of their electrical power from dams, and 70 countries rely on dams for flood control.


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Planning for Dams

Careful planning throughout the siting, design, and construction of dams is necessary for optimal utilization of rivers and for preventing catastrophic dam failure . These planning phases require input from engineers, geologists, hydrologists, ecologists, financiers, and a number of other professionals.
Designers must first evaluate alternative solutions and designs for meeting the same desired objective, whether the goal is to allocate water supply, improve flood control, or generate electricity. Each alternative requires a comprehensive cost-benefit analysis and feasibility study for evaluating its physical, economic, ecological, and social impact.
Once an alternative has been selected, a number of important considerations enter into the design and construction of the dam. These include:

• Hydrological evaluation of climate and streamflows;
• Geologic investigation for the foundation design;
• Assessment of the area to be inundated by the upstream lake (also called a reservoir) and its associated environmental and ecological impacts;
• Selection of materials and construction techniques;
• Designation of methods for diverting stream flow during construction of the dam;
• Evaluation of the potential for sediments to accumulate on the reservoir bottom and subsequently reduce storage capacity; and
• Analysis of dam safety and failure concerns.

When a dam is put into operation, or commissioned, water is released from the upstream reservoir over a spillway or through gates in a manner to satisfy intended objectives. Operating rules for maximizing power generation, for example, include maintaining hydraulic head. In contrast, water levels in flood control reservoirs must be periodically reduced to allow for new storage during anticipated periods of flood hazard. Operating issues, however, can easily become complex and highly politicized and may be difficult to resolve. This is particularly true for river systems containing several reservoirs, for dams serving multiple purposes, and in cases where adverse social, ecological, and environmental impacts are significant.


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