Intro to Alignment Analysis Program [AAP 2.0] for Urban Highway Geometrical Planning and Design
PROGRAM VISUAL BASIC UNTUK PERENCANAAN GEOMETRIK JALAN RAYA, Andreas Siagian, NPM: 9121, tahun 1998, PPS Transportasi, Program Studi Teknik Sipil, Fakultas Teknik, Universitas Atma Jaya Yogyakarta.
Calculation in solving Civil Engineer problems in the past was manually processed using ruler and traditional counting instruments. This working method often took a large amount of time and energy for an engineer. With advance computer technology development, softwares are created as a tool for an engineer to solve from simple to delicate calculations. By using softwares, an engineer able to solve Civil Engineer problems with better time efficiency and higher precisions in the calculation process.
Horizontal and vertical alignments establish the general character of a rural highway, perhaps more than any other design consideration. The configuration of line and grade affects safe operating speeds, sight distances, and opportunities for passing and highway capacity. Decisions on alignment have a significant impact on construction costs. When horizontal and vertical alignments are designed separately from one another, unnecessarily large cuts and fills may be required, resulting in very dramatic and often visually undesirable changes to the natural landscape. One of the ways to ensure the most effective coordination of horizontal and vertical alignments is through the use of a multidisciplinary design team during the planning and engineering phases of a project. On such projects the combined expertise of landscape architects, urban designers, structural engineers, and historic preservationists, in addition to civil engineers and highway designers, has resulted in superior highway improvement projects.
The concept of using a multidisciplinary design team is not new; it was pioneered in the early 1900’s during the planning and design of the Bronx River Parkway in Westchester County, NY After a period of use primarily on large-scale or controversial projects, this approach has come back into more general application as a way to achieve community consensus.
The objective of AAP 2.0 programming is to assist Engineer in designing and constructing efficient and safe highways and roads especially in urban region. AAP 2.0 will focus on urban highway geometrical planning and design especially horizontal and vertical alignment calculations. Visual Basic 6.0 a programming language that is taught in Atma Jaya Yogyakarta Universtiy (UAJY) Faculty of Civil Engineering in the early semesters, will be used to write AAP 2.0 which used Urban Highway Geometrical Planning Standard (SPGJP) released in March, 1992. SPGJP’92 has been the standards used for highway constructions in Indonesia.
AAP 2.0 will help delicate calculations in geometrical planning and design of highway roads which includes:
Super elevation is tilting the roadway to help offset centripetal forces developed as the vehicle goes around a curve. Along with friction they are what keeps a vehicle from going off the road. A super elevated section is proceeded by a transition section. The values of super elevation are determined from the AASHTO Design Guide and are a function of the rate of super elevation and the curve radius. The transitions calculations can be done using the spreadsheet calculator and are illustrated in the sketch below.
2. Horizontal Alignment
Horizontal alignment design based on appropriate relationship between design speed curvature and their relationship with side friction and superelevation. Along circular path, vehicle attempt to maintain its direction via inertia. Turning the front wheels, side friction and superelevation generate an acceleration to offset inertia. Some of the factors that influence the location and configuration of the horizontal alignment include:
– Physical controls – topography, watercourses, geophysical conditions, land use, and man made features
– Environmental considerations – affect on adjacent land use, community impacts, and ecologically sensitive areas
– Economics – construction costs, right-of-way costs, utility impacts, operating and maintenance costs
– Safety – sight distance, consistency of alignment, human factor considerations
– Highway classification and design policies – functional classification, level of service, design speed, design standards.
Besides all of the factors mentioned above, stage possibilities of the construction must be taken into consideration. Pavement improvement and horizontal and vertical alignment development for the future should be done with as minimum cost as possible. By those factors, the precise and accurate horizontal alignment planning and design could make a vital role in the construction of safe, comfortable and economic highway road.
3. Horizontal Curve Design
By knowing the Original Point, coordinate Point of Intersection and Destination Point, AAP 2.0 could determined the curve design including it’s stationing and coordinate necessary to construct the curve. According to SPGJP’92, there are primary 3 curve designs are used in Geometrical Planning and Design for Urban Highway Roads. The 3 curve designs are:
4. Vertical Alignment
The proper relationships between vertical and horizontal curvature result in an aesthetic and easy-to-drive facility. On the other hand, there are some relationships or combinations, which make driving more difficult and less safe. The horizontal and vertical alignments should be in balance. A generous flowing alignment in one plane is not compatible with small and frequent breaks in the other.
AAP 2.0 software
Alignment Analysis Program [AAP] 2.0 software will only run under Windows XP Operating System. Unfortunately, since AAP 2.0 was written using Visual Basic 6.0, the code haven’t been converted to other programming language that enable AAP 2.0 runs under Mac OS X or Linux. (If someone interested in working to convert this codes, please contact me). The codes it self have more than 50.000 characters divided into 1 main form and 5 child forms. AAP 2.0 main function to calculate the geometrical design of a highway based on the Urban Highway Geometrical Planning Standard (SPGJP) released in March, 1992. SPGJP’92 has been the standards used for highway constructions in Indonesia. Below is the explanation of the interface for AAP2.0.
1. Input interface
AAP 2.0 will display an input child window, enabling the user determining the data required to process the design and calculation. The input is divided in to three frames called Planning Classification, Project Data and Point of Intersection (PI) Data. The data must be inputted step per step starting from the first item. Below is step by step explanation in inputting data necessary for planning and designing an highway according to SPGJP’92.
a. Frame: Planning Classification
Item: Road Design Class
Choose one of the Road Design Classifications available in drop menu section. The details about Road Class according to SPGJP’92 are:
Item: Speed Design
Choose one of the Speed Design available in drop menu section according to the Road Class you have chosen. The details about Speed Design according to SPGJP’92 are:
Speed Design Table km/hour
Classification Kecepatan Rencana (km/jam)
Class I 100, 80
Class II 80, 60
Class I 60
Class II 60, 50
Class III 40, 30
Class IV 30, 20
b. Frame: Project Data
Item: Road Lanes amount
Type any number between 1 to 8. Lanes amount in Indonesia are usually 1 to 4 lanes in one road. Over than 4 is used on a Toll Highway.
Item: Starting Stationing
Type the starting horizontal stationing for the road design.
Item: Beginning Project Coordinate X, Y and Elevation
Type the coordinate according to it’s value. Minus value are considered the opposite direction of the positives value.
Item: End Project Coordinate X, Y and Elevation
Type the coordinate according to its’ value. Minus value are considered the opposite direction of the positives value.
c. Frame: Point of Intersection (PI) Data
Item: X, Y, Radius, and Elevation
Type the coordinate according to its’ value. Minus value are considered the opposite direction of the positives value. Radius input must come in positive values. Click the add button after inputting one point of intersection. The interface also enable the user to delete the previous PI data.
d. Click OK to start the process
Feel free to contact me for further info about this software.