Sign Up To The Free Email Newsletter!

Want to get notified whenever we produce the latest content ? Then subscribe now to start receiving hot updates from today.

30 May 2013

CADD Packages

The objective of this architect CAD software review is to provide insight about a few good architectural CAD packages out of the hugely crowded civil CAD market.
  • The cost of architectural CAD landscape design software may vary from free to several thousand dollars. However, I can say from my six years of CAD experience that professional users look for more than just the cost while purchasing such a package. They look for technical features and technical support equally, if not more, than the cost. On the basis of these three factors, the following packages stand out from the crowd.
  • 1. ArchiCAD

    800px-ArchiCAD-12-NHS-3D

    Image Source: Wiki
    • Features:
    Virtual building: It allows the architects to create a 3D virtual building and all the necessary drawings and documentations (like BOM, etc.) are generated automatically from that.
    Renovation: The latest version of the application makes the partial or total “renovation” projects easier by adding the renovation status in all its BIM elements.
    Teamwork Technology: It allows the whole team to work on different aspects of the same project.
    • Suitable for:
    - Large projects.
    • Drawbacks:
    - This is not one of the easiest software package to operate; it requires training.
    • Cost:
    - Around $6000-$9000.
  • 2. Revit

    Revit 8 screen shotImage Source: wiki
    • Features:
    Construction modeling tool: Modeling tool to capture the design intent and generate various drawings and documents of the project later on.
    Point cloud tool: It allows getting the laser scan results of the old buildings to BIM. By this process, renovation projects become easier.
    Conceptual energy analysis tool: This cloud based tool helps architects estimate the energy consumption by the building they are designing.
    Citrix Ready: This tool helps collaborating remotely located team members working on the same projects.
    • Suitable for:
    - Large projects.
    • Drawbacks:
    - This is also not one of the easiest software applications to operate; requires training.
    • Cost:
    - Around $6000-$9000.
  • 3. Chief Architect

    color-elevation chief architectImage Source: Chief Architect
    • Features:
    Design tools: Roof tools, BOM tools, auto dimensioning tool, framing tool, kitchen & bath design tool, electrical and HVAC tool.
    3D modeling tools: 3D modeling, rendering, and 3D virtual tour recording.
    CAD tools: Generating the drawings and layouts, allows import of AutoCAD drawings, can convert CAD object to architectural object.
    Terrain and landscaping tool: It can import GPS or terrain data and produce 2D or 3D model of the terrain; it also allows setting north pointer to define seasonal settings.
    • Suitable for:
    - Large sized projects where a single person is working dedicatedly on single tasks.
    • Drawbacks:
    - Not suitable for collaborating multiple team members on a same project.
    - No resellers outside USA.
    • Cost:
    - Around $3000-$3500.
  • 4. Home Designer Pro

    home designer pro-cover-house-renderImage source: Home Designer
    •  Features:
    Automatic 3D model creation: It can generate 3D model of the building from accurately sealed floor plans.
    Home wizard: This tool allows user to use the existing building style templates or create new ones.
    Design tools: It has automatic roof generation, foundation, and other advanced tools.
    Automated building tools: This tool allows you to create a building design by accepting default standard best practices.
    Quick start guide: This guide will guide the user to get step-by-step help for any type of building project.
    Design tools: Roof tools, BOM tools, auto dimensioning tool, framing tool, kitchen & bath design tool, electrical and HVAC tool.
    3D modeling tools: 3D modeling, rendering and 3D virtual tour recording.
    CAD tools: Generating the drawings and layouts, allows import of AutoCAD drawings, can convert CAD object to architectural object.
    Terrain and landscaping tool: It can import GPS or terrain data and produce 2D or 3D model of the terrain; it also allows setting north pointer to define seasonal settings.
    • Suitable for:
    - Mid-sized projects where single person working dedicatedly on single tasks and user is not an architect.
    - DIY home enthusiast.
    • Drawbacks:
    - It can open only limited numbers of drawing sheets.
    - Not suitable for collaborating multiple team members on a same project.
    - No resellers outside USA.
    • Cost:
    - Around $900-$1200.
  • 5. IntelliCAD

    • Features:
    DWG compatibility: It is compatible with Autodesk DWG files without any data loss. Not only DWG, it is compatible with all the Autodesk API and commands.
    Drawing productivity: This tool is capable of creating 2D and 3D models efficiently. Due to IntelliCAD ActiveX, the drawings and model can be integrated with other office documents.
    Affordability: It is a commercial grade CAD program with a very affordable price.
    Open Source: Source code is available for modification.
    • Suitable for:
    - Users familiar with AUTOCAD.
    • Drawbacks:
    - Lack of support.
    - Advanced features like collaboration tools, scanning tools are missing.
    • Cost:
    - Around $120-$600.
  • These are the few examples of Architect CAD landscape design software quite popular among a range of architectural users. Depending upon the size and nature of project, if you don't find what you need among these, you can find some other applications suitable for you.

References

  • Author's experience and expertise

A Non-stop Method for Building Concrete Structures

The slipform technique of construction allows for the continuous pouring of concrete into walls of a structure and only stops when the full required height of the structure has been reached.
  • Development of the Slipform Technique

    450px-Millennium Tower 5
    Cement, and concrete by its association with it, has an initial setting time of just about thirty minutes, after which the cement and the concrete have gained sufficient strength to remain in the shape into which it has been poured. It is this property that led to the development of slipform building that allows a non-stop method of construction.
    It is this property of early setting that inspired engineers to develop means of moving the formwork so that the concrete can be poured continuously. The height of the formwork is designed in such a way that while the top of the formwork is being filled by concrete the lowest layer of concrete poured earlier has already gained an initial set. When the formwork is moved upwards the concrete that is then exposed remains firm.
    Image Source : Wikimedia
  • Advantages of Slipform Building

    A major cost of concrete structure construction comes in the form of the required formwork to retain the concrete while it retains it necessary shape and gains the necessary strength till it can be safely de-shuttered and be able to support itself and other imposed loads. It also requires the formwork to be continually removed to newer locations and then re-erected. All this requires the continuous use of manpower and lifting equipment like cranes. In the case of slipform building, the formwork is erected only once and remains intact until the entire structure is completed.

    This greatly reduces the cost of the formwork as well as any time that may be required to erect and move it for re-erection, which can result in huge savings in time as well as money.
    The continuous operations also allow for an evening-out of the manpower requirements and also a huge saving in the labor that may have to be periodically employed during otherwise intermittent concreting operations.
    The reduction in the movement of formwork and workers also leads to far more safe working conditions that also make it a major advantage.
  • The Components of Vertical Slipform

    A slipform assembly can only start after the foundations of the walls have been correctly laid and a starter for the walls laid out in its correct alignment with all the necessary steel for the walls already in position. The slipform shuttering is then firmly aligned to this starter with the means of yokes on each side of the shuttering that help to keep the panels in position. The yokes are all connected by horizontal crossbeams. Hydraulic jacks are then installed rigidly to the crossbeams that can all act simultaneously so that the entire slipform shuttering moves upwards. The heights of such slipform shuttering will normally be between 1. 1 meters to 1. 5 meters in height. The yokes and horizontal crossbeams are also used to support a working platform that can afford space for men and materials. The jacks climb using jacking rods that are installed within the concrete and become a permanent part of the structure, or can be retrieved if so desired.
    The design of the working deck and the yokes and horizontal crossbeams are a very vital part of efficient slipform construction. It is very important that the entire structure be such that its rigidity and shape is maintained at all times. It is quite normal for the two sides of the shuttering to be inclined towards each other at the top with the correct wall dimension available at the center. This allows the shuttering to move easily and eliminates any drag that concrete can cause on the shutters to prevent its free upward movement. The rigidity of the supporting platform is also essential so that all parts of the structure move simultaneously. If there is any lag from one part to the other, this can cause the shuttering to drag and make it difficult to be pulled up. It is also possible to reduce wall thicknesses as the construction gains height and arrangements have to be made in the slipform structure that will enable such reduction at regular intervals.
  • Non-stop method of Construction

    409px-Silo Formwork
    Once the slipform shutters along with the jacks and support deck are in position, concreting operations can then commence. Sufficient working space has to be created on the deck to accommodate reinforcement bar activity. The bars have to be continually lengthened and placed in position as per the structural requirements for the wall. The concrete is poured in layers, and by the time the concrete level has reached the top, the concrete at a level 300 mm above the bottom of the panel should have gained the initial set. The rate of pouring of the concrete has to be adjusted so that this is achieved. The slipform is then moved upwards in steps of 10 mm to 25 mm and both the concreting and placing of the reinforcement bars is done continuously till the final height is reached. All jacks are fitted with brakes that act automatically by mechanical means and do not allow the jacks to slip on the jack rods.
    Slipform methods of construction can also be adapted to horizontal structures and are used for paving, canals, and tunneling. The technique is more in use for structures that have continuous walls like silos, chimneys, and piers for very tall bridges. It has also been successfully used for construction of buildings, although this requires the manner of leaving inserts for openings like doors and windows to be decided well in advance, as well as also any necessary inserts to support floor slabs after the walls are constructed.
    Image Source: Wikimedia

References

Highway Construction & Engineering

Highway construction and engineering includes planning, designing, and building of highways. History stands witness that good roads lead to prosperity for distant societies. If a road is well planned and then executed according to the plan, a highway can open the gates of growth and development.

References

Waste Incineration as an Alternative to More Landfills

There are several types of waste incineration plants. The most common type is municipal solid waste (MSW) with the heat providing energy from waste. This is becoming more necessary in many countries throughout the world as we all run out of land-fill sites for our household rubbish.
  • Incineration of waste is not a new process, but the rules and regulations regarding emission of the resultant pollutants to the atmosphere have been tightened and upgraded. This is due to the fumes produced containing dioxin particulates and heavy metals, both of which are dangers to public health.
    The following sections examine the incineration of municipal solid waste incorporating a waste heat boiler to recover some of the energy from waste (EfW). The first section gives a brief overview of waste management techniques and strategies.
  • Waste Management – an Overview

    Waste management plays an important role in the disposal of our waste in an environmentally efficient, safe manner.
    There are a number of basic means of disposing of our waste.
    • Recycling
    Here materials such as paper, glass, plastic, aluminum, and tin cans are sorted by the householder and collected from the curbside outside their property. Vegetation, grass and hedge clippings are collected for composting; the remaining waste is sent to a landfill or an incineration plant.

    Incineration (after sorting)
    Here the recyclable materials are removed before incineration as per the above method.
    • Incineration (non-sorted)
    In this method all the municipal waste is incinerated without segregation of recyclable materials, with the ferrous metals being extracted from furnace bottom ash by magnets.
    • Landfill
    Land-fill usage is either banned or being phased out in major countries of the Western World. DOE and EU legislation has made this method of disposal very expensive through the introduction of a levy per ton for disposal. At the same time, old disused landfill sites produce a gas that can be processed to run gas turbine/engines driving electric generators providing power to the local grid.
    • Gasification
    The MSW is fed into large steel digesters that are free from oxygen and light and heat are applied. The organic waste breaks down through time producing a gas that can be used to run a gas turbine/engine driving an electric generator.
    • Incineration - Energy from Waste (EfW)
    All new plants are required by law to incorporate some form of EfW system through using the heat produced to run a waste heat boiler or a district/community heating system.
    The next section examines one such method for the incineration of municipal solid waste using a waste heat boiler as a means of recovering energy from its combustion.
  • Characteristics of Waste Incineration Plants

    Municipal solid waste incineration is basically a waste treatment process that involves the combustion of waste as an alternative method to using the scarce number of remaining landfill sites.
    Some facilities practice recycling techniques where the recyclable materials are sorted (mostly still by hand) from the incoming waste before being segregated, bagged, and transported to one of the various recycling plants. The remaining waste is tipped into a storage pit from where it is loaded into a hopper on the side of the furnace by an overhead gantry crane.
    The furnace consists of a rectangular steel box lined with fire-brick on the inside and insulated on the outer shell. Oil/gas burners/registers of normal boiler furnace design are fitted, and these project the flames towards the floor of the furnace. Running along the floor of the furnace is a steel-link fire grate that is mechanically driven, picking up the waste at one end from under the loading hopper and, through providing a combustion bed, burning the waste as it moves along the floor. At the end of the grate, the waste that has by now turned to ash falls off the grate into a quench tank. From here it passes under a magnet to remove any ferrous metals before passing into a storage hopper.
    This residue is known as bottom ash. Along with fly-ash, it contains a large portion of the heavy metals such as lead and cadmium. The ash is sent to a landfill or, better, used as aggregate in the road construction industry.
    Combustion air is provided from a forced draft fan that supplies the air to the grate, helping to break-up and mix the waste. This along with the air supplied to the furnace burners ensures complete combustion of the waste, albeit in excess air. Complete combustion takes place at around a temperature of 550°C. Along with this, recent EU directives call for temperature of 850°C to be maintained for 2 seconds per new load, eliminating any bacteria/viruses contained in the new charge of waste.
    Water-tubes that form part of a normal waste heat boiler system are fitted inside the furnace in the path of the hot combustion fumes. A superheater is also positioned in this pathway, before the combustion fumes exit from the roof of the furnace.
    The fumes are now subjected to fume treatment that consists of components in the following order:
    1. Gas Cooler - The gases are still at a high temperature; exiting the furnace after the waste heat boiler at around 200°C. So, before passing to the treatment plant proper they are cooled using a normal water tube cooler.
    2. Particulate Filtration - These minute particulates being assigned a PM10 category are particularly dangerous to us humans as they clog up the respiratory and vascular systems, especially that of the elderly and babies.
    There are several methods of removing/reducing them from the gas-flow.
    • Bag-house Filters
    These fabric-mix filter bags are installed in the bag-house, being open at one end to allow the fumes to enter. As the fumes pass through the bags, the particles and fine dust are trapped; falling down into a storage hopper in the base of the housing. These are very efficient filters capable of removing up to 95% of PM10’s and fine dust from the fumes.
    Many years ago I was an engineer in a copper smelter in Northern Rhodesia, being responsible for the maintenance of the waste-heat boilers that ran off the copper smelting furnace. The fume treatment had not worked for a long time due to lack of spares and the indifference of the workforce to the fumes that were emitted from high brick chimneys. Sulfur was extracted from the fumes through processing in an acid plant, but the particulates and other heavy metals went straight up the chimney-dropping from the resultant plume to land on the local townships and shanty towns. I did manage to get some sort of particulate and fine dust extraction working along the lines of a bag-house filter unit, but that’s another story.
    Today’s filter bags are very robust, being manufactured from durable fine woven fabric materials that can promote a large reduction in particulate and dust emissions.
    The bag-house also has an automatic self-purging/cleaning operation using compressed air to ensure efficient operation.
    • Electro Static Precipitator (ESP)
    This component utilizes the properties of a negative and positive DC current to collect the particulates on steel plates. Once the plates are full, a hammer head strikes the plates releasing the particulates/dust to fall into a hopper at the base of the unit.
    3. Scrubbers
    A wet scrubber consists of a vertical steel tower with the fumes entering at the bottom and passing upwards. A solution of lime and water is sprayed into the path of the fumes removing the sulfur oxide and some of the dioxins (produced from combustion of plastics). These all fall to the bottom of the scrubber forming a slurry of calcium sulfate – (gypsum). This is the material used for producing wall boards, and it is sold off to the building industry.
    4. Gas Drier / De-activated Carbon Unit
    The fumes leave the wet scrubber and enter a drier to remove the moisture before passing through an activated carbon unit/dry scrubber that extracts more heavy metals from the fumes.
    5. Fume Extraction Fan/Chimney
    The fumes are drawn through the activated carbon unit by a centrifugal fume extraction fan that forces them into the chimney. (Some systems incorporate fine, high-pressure water sprays inside the chimney).
    From here the fumes, still containing various pollutants, are propelled high into the atmosphere where they form a plume before dispersing and falling to the ground.
    The layout of key components of a Municipal Solid Waste Incinerator is shown below. (Please click the image to enlarge.)
    MSW Incinerator with EfW
  • Below, a typical chimney and an example of a fire bed/moving grate in operation.
  • Typical ChimneyMoving Grate

Test Youur Civil Enginering skills


  • Question 1 of 15
    #1
    Why is Gypsum Added to Cement?
    It reduces the production cost of cement
    It acts as a retardation agent and controls the setting period
    Gypsum is a coloring agent