Graphics View

The graphics view is the primary means of viewing the bridge geometry. In order to use the graphics views effectively, QuickBG uses mouse actions to apply panning and zooming effects.

• Pan: Click the left mouse button and hold to move the drawing to pan left, right, up, and down.

• Zoom: Click on an area of the graphics window and use the mouse wheel to zoom in and out.

Data Explorer

There are several options to edit an entry. The user can either modify or edit the values in the program’s table cells or through the use of an Excel spreadsheet.

• Data Entry or Edit within the program’s table cells

  • The tab key on the keyboard allows the user to maneuver the date entry horizontally;

  • The enter key on the keyboard allows the user to maneuver the data entry vertically;

  • To copy or paste any data, put the cursor on the table cells and right click the mouse, a floating menu appears. Choose either Copy or Paste button from the menu to perform the desired action.

  • To delete an entry, put the cursor on the first column of each row (the gray column) and right click the mouse; a floating menu appears. Choose the Delete Row button from the floating menu to remove the entry from the list. Note that when cursor is on the data column, the data cannot be deleted, the cursor must be on the gray row in order to perform the Delete Row command and the entire row of data is removed.

• Data entry or Edit using an Excel spreadsheet

  The data can be created in an EXCEL spreadsheet and then copied to the program’s table cells using the Copy and Paste button from the floating menu. Vice Versa, users can edit any existing data by copying out the data to spreadsheet and once done editing, copy back to the program’s text boxes using similar commands.

User Guide

Project

The [Project] tab is to edit the project information, including project title, job number, designer name and date.

Profile

The [Profile] tab is to input the alignment, vertical profile grade and roadway cross section data.

• Alignment

  There are three types of horizontal controlling curves defined in QuickBG: Alignment, Horizontal Base Line, and Profile Grade Line (PGL).

  Alignment is a smooth curve which consists of a sequence of at least two station points with each two consecutive station points in the sequence connected by a curve segment. Smooth means there is no kink between any two adjacent curve segments. Each segment is either line type or circular type. For circular type, value of radius is input with positive for convex shape (counterclockwise), and negative for concave shape(clockwise). The default value of radius is 99999 ft.

  In curved bridge practice, it is convenient to set a horizotal straight line to be tangent to alignment curve at a specific station point and then mark all bridge geometry dimensions based on this horziontal line instead of the alignment curve. QuickBG names this line as Horizontal Base Line.

  The Profile Grade Line (PGL), usually the centerline, sets elevation to which the roadway is to be built. In most cases the PGL is coincident with the alignment curve, but sometimes there exists offset between these two. QuickBG provides the option to define the offset of PGL from the alignment curve.

• PGL

  The profile grade consists of a sequence of vertical curve segment. Each segment is defined by PVI (Point of Vertical Intersection) station, PVI elevation, LVC (Length of Vertical Curve), initial roadway grade G1 and final roadway grade G2 in percentage. The values of station and elevation for PVC (Point of Vertical Curve) and PVT (Point of Vertical Tangency) are computed from the input values. If two consecutive segments are not directly linked, QuickBG automatically insert a line segment to connect the PVT point of the first one with the PVC point of the second one.

• Cross Section

  Cross section is input by setting the slope in percentage across the bridge from the Reference Point, left and right. Slopes are negative when going down away from the Reference Point. Each slope segment is defined by the horizontal length in feet, slope in percentage, segment type (line, circular or parabolic), and the rise if the segment is curved (circular or parabolic). The rise is the height of the curved portion measured at the middle and in the direction normal to the slope, as shown below.

  Fig 1. Curved cross section segment

  Typically the Reference Point coincides with PGL. For special case where the Reference is not on the PGL, QuickBG also provides the option to specify the vertical offset from PGL.

  Double click the cross name in the list to select it for view and edit.

• Cross Section Assignment

  In this Tab, cross sections defined in the previous [Cross Section] tab are assigned to bridge at their starting station points along PGL. For example, if the bridge cross section varies from section A at station P1 to section B at station P2, then input station P1 and section A in the first row and then P2 and B in the next row. The bridge portion between station P1 and station P2 is called Transition Zone. Dimensions of cross section in the transition zone are computed using interpolation of the two end cross sections. Two interpolation approaches are provided in QuickBG: Linear and reversal parabolic.

Pier & Bearing

Straight lines that transversely cross the alignment are called Transverse Lines. Transverse Lines are the primary elements in QuickBG. They are used to define bridge spans and girder lines and classified into three categories according to their functions: Pier line , Bearing line and Dummy Line.

Pier lines are used to determine the number of bridge spans. Each pier or abutment has only one pier line. QuickBG has the default assumption that bearing is sitting in the pier line. At some locations the bearing offsets from the pier line, such as end abutments or piers which support simply-supported beams on each side. For these locations, Bearing Lines need to be specified by the offset from their pier lines. Each pier line has at most two bearing lines.

Dummy lineis for reference purpose only. It is seldom used but would be very helpful in defining special girder types. For example, if a girder has a kink point in the middle of a span, the location of the kink point would be determined from the dummy line that crosses the kink point.

QuickBG provides two ways to define Pier lines and Dummy lines.

• Basic

  The first way, called [Basic], uses the “point plus direction” method. It first specifies the station point where the transverse line intersects with the alignment, and then gives the transverse line direction. The direction is determined by measuring the angle to the line, either form the tangent of the alignment at that station or from the Horizontal Base Line. Counterclockwise angel is in positive.

• Parallel

  The second one, [Parallel], is a fast and convenient way to define those lines which are parallel to transverse lines defined in [Basic]. The location of the Parallel line is determined by measuring the distance from the [Basic] line to the Parallel line.

  There are three types of distance measurement:

  1. Perpendicular distance between parallel Lines

  2. Arc length along the Alignment Curve

  3. Along Horizontal Base Line

  Fig 2. Type of Distance Measurement for Parallel Lines

• Bearing

  As mentioned above, Bearing Line should be defined at pier or abutment locations where the bearings are not sitting in the pier line. Each pier has at most two bearing lines. Bearing Lines are parallel to their respective pier line. The parallel distance is measured with using the same methods as described in [Parallel].

Girder

Deck elevations are computed along Girder Lines in QuickBG. Thus, beam lines, curb lines, parapet lines, and all other lines or curves along which deck elevation needs to be evaluated are treated as Girder lines. For input purpose, Girder lines are divided into two groups, Regular and Irregular. Each group has its own input method as described below.

• Regular

  The regular girders are those which could be formed by simple offset from the alignment or the Horizontal Base Line. Offset is a very convenient way to create new girder because only offset value is needed. Please note that offset for circular curve is to create a concentric circular curve.

• Irregular

  In "Irregular" input, girder line consists of a sequence of points where the girder line intersects with Transverse Lines. Each two consecutive points in the sequence is connected by a segment, which is either line type or circular type. For circular type segment, positive radius gives convex shape (counterclockwise), while negative radius gives concave shape(clockwise). The default value of radius is 99999 ft.

  QuickBG gives three distance measurement methods to define the location of the intersection point between girder line and transverse line.

  1. Distance measured along the specified transverse line, from the point where the specified transverse line intersects with the alignment curve.

  2. Distance measured along the specified transverse line, but from the point where the specified transverse line intersects with the Horizontal Base Line.

  3. Perpendicular distance from the Horizontal Base Line.

  Fig 3. Type of Distance Measurement for Girder Points

• Deflection

  Screed elevation is the elevation at which the bridge deck is set. The elevation is set such that, when the deck and barrier concrete is poured, the structure deflects to the correct finished grade. Deflection due to the selfweight of the framing is NOT included. Typically, deflection due to future wearing surface is NOT included. The screed elevation is given by the following equation:

  Screed Elevation = Finished Top of Slab Elevation + Deflection due to slab weight and barrier weight

  Thus, the input deflection data here is the deflection due to slab weight and barrier weight. The girder deflection shape is defined by specifying the deflection value at some points. Instead of using linear interpolation, QuickBG adopts B-spline method in determining the deflected shape to achieve high precision with even small amount of number of points.

  The first column in the table gives the point location, which is the combination of the span number and the relative ratio in the span that it is located. For example, 2.25 refers to the quarter point in the second span, the whole number 2 represents span No. 2, and the digital number 0.25 means the quarter point in span 2. Downward deflection is positive. Please note the defleciton is in the unit of inch, not feet.

Deck Elevation

The [Deck Elevation] tab is to provide the desired results, including stationing, offsets, lengths, angles and top of roadway elevations.

• Deck Division Approach

  QuickBG provides five different approaches to define the number of division points for each span.

  1. Fixed Spacing (IDOT method)

     This approach is adopted by Illinois DOT. The increments for elevation along girder line are 10 feet with any odd increment not greater than 15 feet or less than 5 feet placed at the end of a span. A new series of 10-foot increments begins in each respective span along the girder line.

     The default value of spacing is 10 feet as required by Illinois DOT, but user could change the value to meet DOT's requirement. The last segement length limitation at the end of a span could be changed too.

  2. Equal Spacing – Fixed Number of Spacing

     A fixed number of spacing is applied to all spans. Each span has same number of division points equally distributed, but the spacing may be different for different span.

  3. Equal Spacing – Limited Maximum Spacing

     This approach limits the maximum value of spacing. The number of spacing in each span is calculated by dividing the span length by the maximum spacing value, and then rounding the result to the closest whole number not less than it. Both spacing number and spacing value may be different for different spans.

  4. User Defined Number of Spacing for each Span

     This approach allows each span having its own number of spacing.

  5. User Defined Transverse Lines

     Similar to the approach in defining pier lines in [Basic], this approach defines the division line by specifying the station point that the line intersects with the alignment and the angle measured from either the alignment or the Horizonal Base Line to the transverse line.

  The desired Deck elevation result can be obtained by clicking Button Excel Output or Text Output. The “Excel output” will automatically run Excel and show the results in Excel in the format required by IDOT.

• Result

  The [Results] tab shows more detailed information on bridge geometry such as coordinates, angle, span length, station, offset, elevation, and so on.

• Setting

  The [Setting] tab is to set up the data format for Excel output file that could be dirrectly linked by CAD draiwng sheets. Different states may have different required format for CAD sheets. QuickBG would add new format into the list as requested by User.