Friday 12 December 2008

Application of road design software HEADS® appropriate to the project requirements

Design of Grade Separated Interchanges

Application of road design software HEADS® appropriate to the project requirements…TechSOFT Engineering Services (I) Pvt. Ltd.

The development of effective road transport system is the primary need of any developing country and the upgrading of existing road network system is essential for the developed countries as the capacity of roads in urban and non-urban highways is reached to saturation level with the passage of time.

The road development involves very high degree of attention by the project Authorities as well as by the Consultants, Engineers and Contractors. Any mistake May result in expenditure of a few millions which could have been avoided. Normally the design of route alignment and the pavement structure decide the cost of a highway project and for this job the best experienced manpower and best available tools must be deployed.

The best available tools essentially Include the selection of most appropriate Highway Design software which must be capable of handling any type of situation and the best manpower is the engineers and other technical staff who have the essential educational background and sufficient experience in working for similar projects and have required level of training to use high quality design software products.

NEXT GENERATION TECHNOLOGY: Presently there are two varieties of Software available based on two basic concepts namely: “Template” and “String” modeling. The first group of products are simple to learn and handle but have substantial limitations in handling today’s demand for road geometric design, Whereas software using “String” modeling technique is efficient for highway projects involving Widening of existing roads, Surface Profile Correction & Strengthening, Design of multi-alignment road sections, varying cross-sections, with or without service roads appearing anywhere along the length, design of Multi-level Grade Separated Interchanges, At Grade Junctions, Design of Split Level Dual Carriageway roads, Hill roads having special considerations, Vehicular Tunnels with sharp turns ranging from 90 to 180 degrees, all types of Rail Routes and Rail Yards, Mass & Light Rail transit system, Airport Pavements for Runway Taxiway Apron etc.

HEADS software from TechSOFT Engineering Services (I) Pvt. Ltd. is based on “String” modeling technique and is today’s established name in offering the users all the facilities described above. It accepts Topographical Survey data from Total Station, Auto level, GPS, Topo Maps, Aerial Photograph, Satellite Imagery Remote Sensing etc. It offers the facility to use Digitized Topo Maps in case of absence of Topographical Survey data. Detailed tables are also generated for Traverse Survey, EDM Survey and Co-ordinate conversion from Spherical (Lat-Long) to Rectangular (Easting-Northing) which is a very complex process and is hardly available in market available products.

HEADS has its own CAD engine and is best appreciated for its Power, Completeness, Versatility, Fastest Processing, Simplicity and Exchangeability of Input and Output with other commonly used Road Engineering software of similar kind and all popular CAD software.

SURVEY, DTM and GPS: String based software generally starts functioning using the Detail Survey data primarily using Total Station instrument. But there are a lot more tasks to do in an actual project, before obtaining the Detail Survey data. These essential tasks are most commonly the Obtaining two Reference points at every 5 Kilometres using GPS instrument, Using the GPS Co-ordinates carrying out Traverse Survey by using Total Station instrument, Obtaining Correct Traverse Co-ordinates by Bowditch or Transit or Closed Link method followed by installation of Reference Pillars to help in carrying out the Detail Survey. These are essential tasks for any Detail Survey project. The GPS data is more reliable if obtained in the form of Longitude and Latitude (than in the form of East North), the Long Lat data may be converted to Easting and Northing by using correct parameters specific to the location in the globe. Once the GPS data are available in Easting and Northing, these become usable by the Total Station instrument. The data conversion needs correct parameters and the process is also quite cumbersome. Additionally the Correction of Traverse Co-ordinates to install Reference Pillars also needs considerable amount of time and effort by the engineers at the project site. Here comes HEADS as the complete one stop solution for all these requirements by the site engineers at simplest effort. Being a String based software HEADS is very versatile to handle various site situations and eventually comes as an ‘All Complete Solution’ for various Transportation Engineering projects.

Co ordinate Conversion and GPS Technology

The instrument GPS (Global Positioning System) is based on Satellite technology. In total about 24 Satellites are rotating around the Earth in various orbits all through the day and taking different times to complete a rotation. For GPS usage 8 Satellites are required in between the First and Second Horizon Circles of the instrument.

If the observer stands in a Plane ground he observes that the sky is touching the ground all around him forming a circle, this is the First Horizon. From his point of observation if a straight line is projected to the sky and rotated to complete a full circle then that is the Second Horizon.

Any circle inside the second Horizon or vertically above is not taken into account, because any object if seen from the top does give any measurement on the height of the object. So to get the height the object is to be seen obliquely. The average observation of 8 or more Satellites gives almost the true height of the object. In case of Ground it is the elevation with respect to the mean sea level.

GPS gives the output in two modes Spherical Coordinate System as Longitude & Latitude in Degree Minute & Second and Rectangular Coordinate System as Easting & Northing in Metres.


If the output is taken in spherical system the user is always safe as the values of Longitude & Latitude are unique for a particular location on the earth. But if any Total Station Survey is to be carried out by using the GPS data as reference point, then the data must be in Rectangular Coordinate system ie, in Northing & Easting in metres.

Here comes the first conversion which is from Spherical system to Rectangular system. If the radius of earth is ‘R’ in metres and Ø1 is the Latitude and Ø2 is the Longitude in Degree Minute & Second then Easting equals to R x (Ø1 in radian) and Northing equals to R x (Ø2 in radian) and finally both the values are in metres.

The above computed values of Easting and Northing in metres are quite large as these are with respect to the Global Coordinate System. Almost every developed & developing country has its own Local Coordinate System. The origin of the Local Coordinate System is separated from origin of the Global Coordinate System by two distances X-Offset & Y-Offset in metres. The axes of the Local Coordinate System is also rotated about X & Y axes of the Global Coordinate System by angles Lat-Offset & Long-Offset, both in Degree Minute & Second.

The Second conversion comes by deducting the X-Offset and Y-Offset values from the Easting & Northing values already computed as stated above to get the reduced values of Easting & Northing. Next the rotations of both the axes Lat-Offset & Long-Offset are also applied on the reduced values of Easting & Northing to get the final values of Easting & Northing which are specific for a location in a particular country.

The Earth shape is not spherical rather it is of irregular shape because of High altitudes at locations of numerous high mountains and Low elevations at locations of various oceans. This irregularity in the shape of the globe does not give a unique radius ‘R’. The problem is solved by considering different radii valid over different regions on the globe. The radius valid for a country may not be applicable in its neighboring country.

The parameters relating the Local Coordinate System of a country to the Global Coordinate System are X-Offset, Y-Offset, Lat-Offset & Long-Offset. These values are also expected to be different for different Country.

So, it is very important to calibrate the GPS instrument by using appropriate country specific parameters Radius of Earth, X-Offset, Y-Offset, Lat-Offset & Long-Offset before using the GPS instrument and when the output is desired in Rectangular Coordinate System which are Easting & Northing in metres. Otherwise the market available GPS instruments are normally holding the parameters of the country of its origin and will result incorrect coordinates.

It is therefore advisable to receive the GPS output in Spherical Coordinate System and Convert into Rectangular Coordinate System using the country specific parameters. The facility is available with HEADS under menu option ‘DGM-Coordinate Conversion’. User may change the default parameters in the dialog box with parameters obtaining from the Survey Department of the country.

The Parameters for Transforming Longitude / Latitude to Easting / Northing to be given to yield the desired transformations are described below. These are default parameters and are applicable to a particular part in India, User has to change the parameters as applicable.

1. Spheroid : Everest 1956
2. Lambert Conformal Conic Projection
// Spheroid Parameters
A = 6377301.243; // India 1956
F = 1.0/300.8017; // Everest
// False Northing & Easting
x_offset = 3000000.0;
y_offset = 1000000.0;
// Origin - Zone Specific
lat_offset = 19D 15m 14.9818s
long_offset = 79.0D 0m 0s;
// Standard Paralells Specific
PHI1 Æ1 = 17D 15m 0s;
PHI2 Æ2 = 21D 15m 0s;

For Converting from Longitude & Latitude to Easting & Northing user has to select the Radio button From WGS84 to LCC located at top right hand corner of the screen. User Input file may be named as LongLat.TXT containing the following data:

HEADS
130,COCONV
131,Conversion from Long Lat to Easting Northing
132,79 2 22.144 20 3 24.97384
132,79 4 51.829 20 1 1.082126
132,79 4 43.159 20 1 10.11755
132,79 4 29.555 20 1 13.29371
132,79 4 15.749 20 1 22.25524
FINISH

Output data will always be in the Report File : EastNorth.REP

Easting Northing
(Metres) (Metres)
3004127.79184 1088809.39141
3008476.63357 1084388.68017
3008224.67406 1084666.24799
3007829.48842 1084763.68565
3007428.36707 1085038.93019

For Converting from Easting & Northing to Longitude & Latitude user has to select the Radio button From LCC to WGS84 located at top right hand corner of the screen. User Input file may be named as EastNorth.TXT containing the following data:

HEADS
130,COCONV
133,Converted Data from WGS84 to Lambert Conformal Conic Projection
134,3004127.79184 1088809.39141
134,3008476.63357 1084388.68017
134,3008224.67406 1084666.24799
134,3007829.48842 1084763.68565
134,3007428.36707 1085038.93019
FINISH

Output File will always be the Report File : LonLat.REP

Longitude Latitude
(Deg Min Sec) (Deg Min Sec)
79 2 22.144 20 3 24.97384
79 4 51.829 20 1 1.082126
79 4 43.159 20 1 10.11755
79 4 29.555 20 1 13.29371
79 4 15.749 20 1 22.25524

AERIAL PICTURES: HEADS accepts Aerial Pictures and allows to set True co-ordinates in the picture, which is a unique feature of HEADS. This allows designers to do the actual interactive design for the Route Alignment interactively On-Screen. This helps Project Authorities understand the proposed route with respect to the various land uses along the corridor.

HEADS produces detailed reports for every analysis and design and CAD drawings for Plan & Profile, Cross sections with designed Pavement Layers, Mass Haul diagram, Contours, Ground Models, DTM, Digital Mapping, Benched/Stepped slopes for Cut & Fill in Embankment construction, Embankment Toes on either side, Road side Drains, Gabion walls in Hill roads, Diagrammatic details for Horizontal & Vertical alignments and Super Elevations, 3-Dimensional views and detailed design reports required for preparation & submissions for various Detail Project Reports.

HIGHWAY / EXPRESSWAY: For the design of HIGHWAY and 6/8 Lane EXPRESSWAY at design speed 120 KPH or more by following relevant International Standard, HEADS is the most appropriate road design software. The DTM, Contours, Alignment Geometrics, Construction Drawings for Plan-Profile-Cross Sections and Site Setting Out, Drainage, Bituminous & Concrete Pavement Design, Bituminous Mix Design, 3D Perspective views can be produced with best possible accuracy.

INTERCHANGES: In the design of Multi Level Grade separated Interchanges HEADS has the edge over all other road design software. The Loops, Ramps and Slip roads can be formed with best possible accuracy and in minutes time.

HEADS is simple because it has full featured built in CAD engine.

HEADS is powerful because it is based on versatile string modeling technology. Although this technology is used by various other softwares, but HEADS applies it with a very high degree of efficiency, accuracy and simplicity which are achieved by carrying out extensive research work by the engineers and developers in TechSOFT.

HEADS allows the user to check the design from various view points and once finalized user is able to present the design from various view points as desired. Layered CAD system allows to produce the design in 3D perspective. This not only gives the virtual reality of the project but also enables the user to check the work for safety aspects.

HEADS helps the user for not comprising with the safety aspects and enables to produce the best work suiting to the Site situation, Traffic demand and Budgetary constraints.

Technical support team of TechSOFT is having Senior Post Graduate Highway Engineers with 10 to 30 years of international experiences. They are available to guide the user of HEADS to produce the best possible work suiting to the existing site situation. If you are having HEADS and the Survey Base Plan of the site, then contact TechSOFT over the internet with the Survey Base Plan and explaining your requirements and next you are just DONE…!

Using modernized software technology the on screen interactive design allows the user to have the facility of Element method of alignment design and produce best design work for Multi level Grade separated interchanges satisfying various design requirements like sight distance, weaving length & maximum grades.

HILL ROAD DESIGN: Design of Roads in Hilly Terrain requires special techniques and the appropriate technology is available with HEADS to design Hair Pin bends, Provision of Retaining wall on the Fill side and Gabbion wall on the cut side. Some times there is need for varying slopes on the cut side depending on the depth of the cut. HEADS interface facility takes care of all these requirements and produces Plan, Long Section and Cross Section drawings following the project requirements with zero compromise.

For the design of HILL ROADS, HEADS is ultimate road design software. The Alignment Geometrics where side slopes in Cut & Fill are varying with depth of cut or Fill, Hair Pin bends, slope restriction by vertical drops for retaining walls can be produced with best possible accuracy.

HIGHWAY STRENGTHENING/WIDENING: In developing countries most of the projects are widening of the existing road carriageway. This needs strengthening of the existing carriageway with Profile correction followed by laying of Bituminous overlay at the top and on the other side there is construction of a new carriageway with full Pavement structure. This needs two separate designs for two carriageways in respect of Horizontal and Vertical alignment. This is best done in HEADS using the versatile String technique.

PAVEMENT DESIGN: HEADS offers AASHTO method of Pavement design for Flexible Pavement with stage construction facilities, Rigid Pavement by CRCP & JRCP, Pavement Overlay by Benkelman Beam Deflection test data and Design of Bituminous Mixes of Bituminous Concrete, Semi Dense Bituminous Concrete, Dense Bituminous Macadam & Bituminous Macadam based on Marshall Test data for Bulk Density, Stability and Flow and Blended Grading of aggregates with diagram. All the designs are generated with detailed illustrated design calculation report with relevant references to AASHTO Tables & Charts. The facility for computation of Equivalent Standard Axles in Millions (MSA) is also available with this system.

HIGHWAY DRAINAGE: HEADS provides facility for the Hydraulic design of Highway Drainage using rainfall data in the region. Rate Analysis is also available for various Road and Bridge items. The detailed estimation of Bill of Quantities for construction items will enable speedy estimation of the project cost.

OPTIMIZING VERTICAL PROFILE: There are two different situations for Optimizing Vertical Profile. One is Optimization for Earthwork in Cut & Fill. This situation occurs when the road alignment is taken through virgin ground and there is significant ups and downs in the ground. In such cases it is the engineer’s requirement to design the earthwork up to the formation level with due consideration for HFL and to keep the quantum of borrow earth as minimum as possible.

The other situation occurs when the road alignment is taken over an existing road and it has Black top surface in fair to good condition. This requires strengthening of the existing surface to withstand the present and future traffic load. The common treatment is application of Profile Correction Course for an average thickness of 50 to 60 mm and followed by construction of Pavement Overlay most commonly by using Bituminous Macadam.

TUNNEL DESIGN: HEADS is the ideal solution for the engineering design and construction of vehicular and Railway Tunnels. All market available road / highway design softwares are not meeting the requirements of Tunnel engineering. A truly 3 Dimensional drawing generating software is essentially required to handle various demands of the design office.

Every design trial has to produce real 3D drawings for Plan, Profile and Cross sections to enable the designer to audit the work for various aspects of the design and safety standard.

Any design must balance the efficiency as well as the economy of the work done and for this the designer must have the best available software. The software used for such work must provide the user with all essential and desired features to make the work best in all respects. Absence of an essential feature in the software may prevent the user from making some important considerations and finally leads to produce a deficient engineering, some times substantial design work leads to additional cost.

Heads produces real 3D drawings along with dynamic 3D visualization and drawings are compatible to all popular CAD drafting software.

TUNNEL CONSTRUCTION: The design Audit is extremely important during the Tunnel construction. Any deviation of the Tunnel axis from the original alignment must be rectified as soon as it is detected. For an early detection appropriate instrumentation is essential.

Other than the Tunnel axis the measurement of deviation may also be essential for other relevant points in the cross section. The comparison is done by using the original design alignments through those points. So the original design must be available for alignments through those points.

In normal straight sections and in curved sections it is essential to generate alignment with shifts in horizontal & vertical directions at various locations and elevations. Because of the super elevation calculated from the curve radius and design speed, the tilt is more at greater height & distance. This may lead to reduction of the lateral clearance between the coach top edges and the side walls of the Tunnel. The deviations by TBM at any station are numerous, the final shell alignment is fixed by Curve fitting mentioning limits along both the axes.

HEADS creates such most essential Tunnel cross section drawings taking points at various offset distances and elevations in the cross section to create the dynamic coach profiles and make the audit possible in true sense. In Tunnel engineering HEADS is the most essential software to produce engineering reports and drawings with most of the information required and with best sophistication.

INTERSECTION CAPACITY ANALYSIS: “SICap”- (Signalized Intersection Capacity analysis) is another product by TechSOFT in the application of Transportation Engineering which may be used for the Analysis of Traffic Saturation in any Urban Street. This has followed the guidelines of “Highway Capacity Manual-HCM 2000” by Transportation Research Board of Washington, USA to determine the Level of Service (LOS) of a Road Intersection.

AIRPORT CONSTRUCTION: HEADS provides all complete solution in the construction of Runway, Taxiway, Apron, Tarmac, Turning Pad, Service Bay etc. The Geometric Design, Pavement Design and Cost Estimation are the final deliverables from HEADS. The Detailed Design Reports and Construction Drawings fulfill the International Specifications & Standards. The Drawings are fully informative and sophisticated. The technology used in HEADS is best among other products available in the international market place.

RAILWAY ENGINEERING: “HEADS Rail” is another product by TechSOFT which contains Design of Points, Crossings, Track Diversion in case of Repairing, Curvature, Train Resistance & Haulage Capacity on Grades and Track stresses.`

HEADS Rail is applicable for Railways for design speed of 135 Kilometres per Hour or more, Standard gauge, Broad Gauge, Meter gauge, any defined maximum “Cant” at Super elevated sections giving inner edge rotation, Curves with Clothoid Transitions, Earthwork Estimation, Construction Drawings, Design of rail Yards etc.

Land Development & Grading: “HEADS Site” is another product by TechSOFT which handles Topographical Survey, Spatial Data Processing, Site Leveling and Grading is the primary job for Land Development, Housing Projects, Industrial Plant Projects, Extension of Urban Areas etc. These involves tasks like Leveling, Grading, Planning of Platforms for Constructions of structures, Site for Stadium, Hospital, Parks, Public Utilities, Roads, Road Junctions, Swimming Pools, Electrical Sub Stations, Rail Stations, Airstrips, Truck Lay Byes, Bus bays, Parking Lots, Water Distribution System, Drainage, Landscaped areas etc. All these are handled by designing suitable Ground Sites in the simplest and best ways in HEADS Site. The various Planning, setting out and Construction Drawings, Estimation of Earthwork for Cut & Fill are generated with highest possible level of accuracy and with sufficient information details. HEADS Site is the most complete and best software in the international market place to design sites most effectively.

CONCLUSION: A String software is supposed to handle all sorts of design requirements specific to the various site situations but at the same time it must be easy to master and provided with best quality technical support by Senior Highway/Transportation engineers in the preparation of Design projects.

RECOMMENDATION: Engineers and Professionals who want to learn more on the design of Highway Widening, Profile Optimization, Design of Multi Level Grade Separated Interchanges, Control on operations of Micro Processor based Tunnel Boring Machines-Pavers, Design of Rail Routes-Yards-Points-Crossings, Airfield Pavements, Hill Road Alignments, Use of Aerial Photos & Satellite, Survey Referencing by Traversing and Installing Pillars, Creating of Digital Terrain Model, Contours, Grids, Survey Base Plan, Design of Highway Drainage and Pavements, Analysis of Item Rates in Construction etc. are suggested to visit the Web site www.headsview.com and try the various Tutorials and Training modules collected from various live project data worldwide using String Modeling concept which supports various project needs stated above. This will help the engineers select the software appropriate to the requirements of the project. The contact email addresses are: techsoft@consultant.com and dataflow@mail.com .

HEADS® Introduced by TechSOFT Engineering Service (I) Pvt. Ltd.
(Protected by U.S.A Copyright and Trademark)

Email: techsoft@consultant.com and dataflow@mail.com
Web site: www.headsview.com and www.techsoftglobal.com

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