HLR Section 4 |
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Vehicle Data |
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CONTENTS | |
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Other Links: | Main Index | Analysis Options | Route Data | | |
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4.1 HL Vehicle Description Data | |
4.1.1 Entering & Saving Vehicle Data Vehicle data for an assesment can be entered in one of two ways. Either via the Vehicles tab on the Application Data Entry form, or via the main menu options: Vehicle/Input data for a new vehicle. In either case, a Vehicles form (similar to the one illustrated below) will be displayed. The data fields and parameters are described as follows: Vehicle Name Enter a vehicle name or description. If this field was originally left
blank in the job ID tab the name you enter here will be echoed back into that form. A unique value should be entered into this field if you intend saving
the vehicle to the data base. Otherwise any number can be used (or it may be left blank). By default it is set
to the heavy load application number. Enter the total number of axles in the vehicle. The system will warn
you if you enter more than 50 axles (just in case you ve inadvertently entered more than you really need), and
will not allow you to specify more than 100. Enter these only if you believe they may cause potential problems for some structures along the proposed route. HLR will only perform a height/width check if either (or both) of these dimensions are present in the relevant structure data file. (Note that HLR will automatically insert the maximum axle width into the Overall Width field if you leave it blank). Axle Load Data This button accesses the Load Ratio Module. Refer to Section 6.8 for a detailed description of what this module does. (Note: This module has nothing to do with the Load Ratio method for performing an assessment of structures that have no moment capacities). Save Vehicle to Database Retieve Vehicle from Database Refer to Section 4.1.2 below for details.
4.1.2 Retrieving HL Vehicles from Database In either case the Heavy
Load Vehicles Database form will appear, with all available
HL vehicles ranked by number of axles (in ascending order). Highlight the required vehicle and either click OK to load it, or Preview to obtain a scaled representation
of the axle layout. Once selected, the vehicle data will be loaded into the data entry table and can then be edited
by adding, deleting and changing axle information. To sort vehicle numbers in numerical order, click the button labelled Sort Vehs in Num Order (repeated clicks of this button will toggle between numeric and alphabetic sorting). HLR sorts numerically by first prefixing all numbers with zeros then performing a sort in alphabetical order. However, there are a number of limitations that you must be minful of. Numbers with a single alphabetic suffix character will be properly sorted, but those with more will not. Furthermore, vehicle numbers longer than 6 characters will be omitted from the numeric sort altogether, although they will be sorted alphabetically. Unwanted vehicles can be deleted from the database by clicking the Delete button. (Warning! There is no undo facility!) |
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4.2 HL Vehicle Loading Data | |
4.2.1 Axle Load Data For each axle enter the axle load (in kN); the relative distance from the previous axle (in metres - note that the distance for the first axle must always be set to zero); and the axle width (m). Every axle can have a different load and spacing. To replicate an entire row of data, place the cursor at any point in the row to be replicated then click the Replicate Data button. All cells, from the one at the cursor position to the last one in the table, will be filled with values identical to those in the source row. 4.2.2 Width-Modified (Reduced) Load (kN) This option has been provided to modify heavy vehicle axle loads according to axle width (Wa) and the type of structure being loaded (i.e. timber or concrete). If any of the axle widths in the heavy load vehicle exceed the limits specified on the Vehicles tab (and in the Options/ Defaults Settings form), HLR will multiply each axle load by the relevant factor (refer to the document "Width-Modified Axle Loads.pdf" for details). The modified axle loads will then be used to determine the heavy vehicle moment and shear effects. To suppress the use of width-modified (reduced) axle loads ensure that the tick box labelled "Use width modified axle loads in analysis" remains un-checked on the Analysis Options form. (This can be set as the default state via the Options/Default Settings menu items). During analysis HLR checks if girders are present in a structure and, if they are, it will use the width-modified (reduced) axle load when calculating the moments and shears generated by the heavy load vehicle. The exception to this is if the bridge is flagged as having a girder Type 9 (indicating that it is an NT type structure). In this case the axle loads will be divided by a factor derived from an empirical Axle Width - Vehicle Load Reduction relationship given in the Options / NT-Factors form. Note that the division will occur at the time of analysis and not when the vehicle loading data is being entered here-in. |
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4.3 HL Vehicle Database | |
4.3.1 Retrieving & Viewing HL Vehicles Vehicles in the data base can be retrieved and viewed in one of two ways:
In either case a table displaying all available HL vehicles will appear, ranked in ascending order of number of axles. Vehicles can also be ranked by vehicle number, vehicle name or gross mass by clicking onto the title bar of the required field. Sorting can be done in either ascending or descending order - simply click the title bar again until the required ranking is obtained. To sort vehicle numbers in numerical order, click the button labelled Sort Vehs in Num Order. HLR will execute this by first prefixing all numbers with zeros then performing a sort in alphabetical order. However, there are a number of limitations that you must be minful of. Numbers with a single alphabetic suffix character will be properly sorted, but those with more will not. Furthermore, vehicle numbers longer than 6 characters will be omitted from the numeric sort altogether, although they will be sorted alphabetically. Note that the exact location of all database files can be specified using the facility provided under Options / Directory Paths. 4.3.2 Deleting Vehicles Unwanted vehicles can be deleted from the database by highlighting the redundant vehicle and clicking the Delete button. (Warning! There is no undo facility!) If you wish to delete whole blocks of vehicles, use the main menu option: Vehicle / Delete HL vehicles from the database. Highlight the range of vehicles to be deleted using the normal Windows convention then click the Delete button. (To do this, select the first row in the normal way, then depress and hold the Shift key while clicking onto the last row in the block). 4.3.3 Data Base Layout & Format The vehicle database consists of three related ASCII (text) files all of which are stored in the ..\HLR\Database directory viz: HLV1.TXT, HLV2.TXT and HLV3.TXT . (Note that the exact location of all database files can be specified using the facility provided under Options / Directory Paths). HLV1.TXT Each row (record) represents one unique heavy load vehicle. Data in each record represents, respectively, the vehicle number, number of axles, gross mass (in tonnes) and vehicle description. HLV2.TXT Each row (record) represents one unique heavy load vehicle. Data in each record represents, respectively, the vehicle number, vehicle description, number of axles, gross mass (in tonnes), total weight (kN), overall length (metres), overall height (m) and overall width (m). HLV3.TXT Each row (record) represents a single axle of a given heavy load vehicle. Data in each record represents, respectively, the HL number, axle number, axle load (kN), axle distance (m), axle width (m) and the width-modified (reduced) load (kN). Each vehicle will therefore have as many rows of data as there are axles. 4.3.4 Printing HL Vehicle Data If a heavy load vehicle has already been defined/loaded into the table on the Vehicle tab, click the Print button in order to print it. If a vehicle has not yet been defined, get one from the HL vehicle database. Note: The data is first displayed in a browser window. If satisfactory, it can be then printed by clicking the Print option on the browser's icon bar. |
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4.4 Design & Legal Vehicles | |
4.4.1 Creating a New Design or Legal Vehicle | |
Design and Legal vehicles are those used in the original design of the structure
and are entered as a vehicle name into the structure database (e.g. as "T44" or "B-Double 62.5t"). If moment capacities are not present for a structure the heavy load assessment will be based on a comparison of empirically derived moments or moment ratios, (depending on whether the bridge is continuous or simply supported). The technique essentially compares the maximum moment generated by the heavy load vehicle to that of the original design vehicle (which, if known, would normally be entered into the structure data base - refer to Section 5.2). For a detailed description of the methodology used in the ratio method for simply supported structures consult Section 6.3. For continuous structures with no capacities refer to Section 6.9. Design vehicles are also used in the LoadRatio module. This is essentially a tool for rapidly calculating the ratios of maximum moments and shears of a given heavy load vehicle to one or more design vehicles across a range of spans (refer to Section 6.8 for details). A number of "standard" design vehicles have already been incorporated into the Design Vehicle database including:- the Highways & Local Government truck (1927); the HS20 truck (NAASRA 1947-based on AASHTO); the NAASRA (1976/1992) T44 truck; and the AUSTROADS 1998 MS1600 vehicles (together with relevant lane loading). Others can easily be created and stored in the database using one of the two methods described below. (a) On-the-fly from the Structure Data form The Structure Data tab has a button called Add a new Design Vehicle (or Add a new Legal Vehicle) that will enable you to create a new design/legal vehicle "on-the-fly". When clicked the form shown below will be displayed (note that there is a slight variation for a Legal Vehicle). Refer to Section 4.4.2 for a description of the required vehicle data. (b) Using the Vehicle option in the Main Menu bar From the Main Menu bar click on Vehicle then select either Create a new Design/Legal Vehicle to add a new vehicle to the database or Edit an existing Design/Legal Vehicle if you wish to modify a vehicle that already exists in the database. In either case a form similar to the one shown below will appear. Enter data as appropriate (refer to Section 4.4.2 below). |
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4.4.2 Vehicle Data
Select a Vehicle Name that is short and descriptive (e.g. HLP400). It is preferable not to include blank spaces or symbols, although the dash (-) or underscore ( _ ) symbols are permitted. If the vehicle is to appear as a default in the LoadRatio Design Vehicles window, append an asterisk to the vehicle description. For continuous bridges with no pre-defined capacity data HLR will attempt to estimate a capacity using the original vehicle(s) on which the design of the structure was based (this would normally be specified in the structure database). Entering a 'DLA type to apply to this vehicle' will force the program to use the design code selected from the drop-down list in calculating the DLA factor to apply to the design vehicle moment (not applicable to Legal Vehicles). Enter a uniformly distributed load (kN) only if the UDL is to act concurrently with the Design vehicle in the LoadRatio module (refer to Section 6.8 for details). This parameter is not used during the normal HL assessment process and is not applicable to Legal Vehicles. Up to 100 axles may be specified for the design/legal vehicle. The first axle must be assigned a zero spacing value; the spacing between all other axles is relative to the one before. Note that you will have to use the ENTER and arrow keys, not the TAB key, to navigate around the table. To enter data into rows that are not visible in the table use the right-hand up and down scroll keys. Once all data has been entered, save the modified vehicle to the database by clicking on the Save Vehicle Data button. All data is saved in ASCII text form to two files residing in the ..\Database subdirectory (refer to Section 4.4.5 for a description of the database layout and format). |
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4.4.3 Edit an Existing Design/Legal Vehicle From the main menu at the top of the form select Vehicle / Edit an existing Design (or Legal) Vehicle. A Design (or Legal) Vehicle dialog box similar to that shown in Section 4.4.1 above will be displayed. From the drop-down box labelled Select vehicle from Database choose the vehicle you wish to edit. Change the data to suit your requirements then re-save the ammended vehicle to the database. For a detailed description of the data fields on this form refer to Section 4.4.2 above. |
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4.4.4 Delete Design/Legal Vehicles From the main menu at the top of the form select Vehicle / Delete an existing Design (or Legal) Vehicle. The total number of vehicles in the database will be displayed in a table sorted by vehicle number. The columns can be automatically sorted in ascending or descending order by simply clicking onto the title bar of the required field. Note: Block deletion of design vehicles has been disabled in this form - they can only be removed one at a time. In the case of the Legal Vehicles table please do NOT delete the first row. |
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4.4.5 Design Vehicle Data Base Layout & Format Design Vehicle data is written to two relational ASCII text files that are stored in the ..\HLR\Database directory viz: Design Vehicles.txt Each row (record) in this file represents one unique design vehicle. Data in each record represents, respectively, the vehicle name, vehicle description, number of axles and the associated uniformly distributed load (if any). An asterisk appended to the vehicle description signifies that the vehicle will appear as a default design vehicle in the Load Ratio module (refer to Section 6.8 for details). Design Vehicles Details.txt Each row (record) in this file represents data for a single axle of a given design vehicle. Data in each record represents, respectively, the vehicle name, axle number, axle load (kN) and cumulative axle distance as measured from the front axle (m). Note that axle spacings are stored in the database as cumulative distances from the lead axle and not as relative spacings. Each design vehicle will therefore have as many rows of data in the file as there are axles. |
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4.4.6 Legal Vehicle Data Base Layout & Format Legal Vehicle data is written to two relational ASCII text files that are stored in the ..\HLR\Database directory viz: Legal Vehicles.txt Each row (record) in this file represents one unique legal vehicle. Data in each record represents, respectively, the vehicle name, vehicle description and the number of axles. Legal Vehicles Details.txt Each row (record) in this file represents data for a single axle of a given legal vehicle. Data in each record represents, respectively, the vehicle name, axle number, axle load (kN) and cumulative axle distance (m). Note that axle spacings are stored in the database as cumulative distances from the lead axle and not as relative spacings. Each legal vehicle will have as many rows of data in the file as there are axles. |
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