Civil Engineering Systems CAD Design of Pedestrian / Bicycle Link Assoc Prof Jon Bunker Bulimba Creek, Minnippi Parklands, Tingalpa 8.7km Some Definitions TermUnitsMeaning Chainage (CH)metres (m)Distance along an imaginary spline representing the control line (centreline) of a road from a starting reference point Australian Height Datum (AHD) metres (m)Datum for altitude measurement in Australia. In 1966-1968 mean sea level was assigned the value of 0.000m Natural Surface Levelmetres (m)This is the ground level, whether on land or under water. Its height is referenced from AHD Highest Astronomical Tidemetres (m)The highest level which can be predicted to occur under average meteorological conditions and any combination of astronomical conditions Some Definitions TermUnitsMeaning Plan ViewChainage in m A plane view of the location of the designed road spline looking down from the sky Elevation View (Profile)Chainage in m, AHD in m A plane view of the designed road spline with Chainage as the X axis and AHD as the Y axis (often distorted as 10 times the horizontal) Gradientm/mThe slope of the designed road spline up or down a straight grade (hill) Bridge Soffitm above AHD The lowest point of the bridge structure, normally at the centreline of the navigation channel Some Definitions TermUnitsMeaning Cross-section ViewWidth in m, AHD in m A plane view across the road at a particular Chainage on the designed road spline, with width as the X axis and AHD as the Y axis Crossfallm/mOn the cross-section view at a particular Chainage, the slope of the road away from the centreline to drain water Superelevationm/mOn the cross-section view at a particular Chainage, the slope of the road inwards around a horizontal curve to stabilise vehicles Location of Proposed Alignment and Existing Natural Surface Levels G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mNorth Towards Points A and B G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mB A North Towards Point B G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mB East Towards Point B G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mB North Along Fursden Drain G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mNorth Towards Existing Bridge G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mNorth Towards Existing Bridges South Abutment G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mNorth Across Existing Bridge G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mSouth Towards C from near G G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mC Location of Proposed Alignment and Existing Natural Surface Levels G (ch 150m, 1.7m AHD)(1.0m)(1.0m)E (ch 130m, 2.0m AHD)F (ch 140m, 1.9m AHD)D (-2.5m)25mShared Bicycle/Pedestrian Path including bridge: Proposed Geometry Start PointEnd PointGeometric Element Type Mathematical Form Proposed Horizontal Alignment (Plan View) ABtangentstraight line BChorizontal curvecircular arc CEtangentstraight line EGhorizontal curvecircular arc Proposed Vertical Alignment (Profile = Long Section) ABstraight gradestraight line BCsag vertical curveparabola CEcrest vertical curveparabola EGsag vertical curveparabola General Design Parameters When we design a new road (in this case shared path) we need to use design parameters from reliable sources: Austroads Guide to Road Design (Austroads n.d.) Client specifications Im giving you the values you need to use General Design Parameters Design ParameterValueSourceInterpretation Bicycle design speed20km/hClient specified(Used for other parameters) Path typeShared use path, recreational Client specified(Used for other parameters) Horizontal curve (HC) minimum radius 10mAustroads, 2014Ensure no HCs have radii less than this value SuperelevationDo not applyClient specifiedUsed in design of cross-section/s Crossfall2.0% (towards creek) Client specifiedUsed in design of cross-section/s Shared path width4.0mAustroads, 2014Use to design cross-sections Bridge profile on riding surface (long section) Parabolic shapeClient specifiedEnsure in design Bridge width including additional lateral clearance to outside rails 4.0 + 2*0.5m = 5.0m Austroads, 2014Use to design cross-section/s General Design Parameters Design ParameterValueSourceInterpretation Highest Astronomical Tide (HAT) of Bulimba Creek 1.65m above 0.0 Australian Height Datum 2015 Semidiurnal and diurnal tidal planes, Queensland, Maritime Safety Queensland Use to calculate minimum height (m above AHD) of underside of bridge at D and therefore design bridge profile Minimum height of bridge soffit above HAT of Bulimba Creek 2.0mClient specified Maximum gradient5.0% over 80m maximum length or 7.0% over 35m maximum length Austroads, 2014Use to design long section General Design Parameters Design ParameterValueSourceInterpretation Minimum stopping sight distance 25m (5.0% gradient downhill) 30m (7.0% gradient downhill) Austroads, 2014Ensure design meets appropriate value between bridge and each intersection (i.e. between D and B, and between D and F) Minimum vertical curve length 7.0m (5% upgrade to 5% downgrade) 9.0m (7% upgrade to 7% downgrade) Austroads, 2014Ensure design meets appropriate value on bridge, and each approach VC (i.e. B to C, and E to F)Path to path intersection angle Between 70% and 90% Check at both intersections Intersection splay in corners minimum radius 2.5mAustroads, 2014Use to design intersections on plan Bridge Profile Concept Design Bridge over Bulimba Creek may take a form similar to this You will need to create a concept design that is: Safe Functional Aesthetically pleasing Your Design Requirements 1. Illustrations of cross-sections at important locations on path and bridge including but not limited to the points of interest shown on Figure 1; 2. Control line (centreline) design of horizontal alignment of replacement path between Point A and Point G including new bridge using aerial photograph base; Your Design Requirements 3. Control line (centreline) design of vertical alignment of replacement path between Point A and Point G including clearance of underside of bridge at Point D above HAT of Bulimba Creek to avoid interference with canoe trail; 4. Location and design on plan view of repositioned T junction of existing south west path to Fursden Road with realigned path at B; Your Design Requirements 5. Location and design on plan view of repositioned cross intersection of existing north west path with realigned path at F; 6. Modification of concept elevation drawing of bridge provided to you (looking downstream), but which you shall modify to be true to design aspects 1 to 5 above; Your Design Requirements 7. Design justification memorandum to accompany design components, including discussion of clearances to pathside furniture, signage and other objects, surfacing materials and pavement markings, drainage, and user friendliness; 8. Team Working Attachment which is a collation of your team working evidence including team agreement checklist by each member, team meetings agenda and minutes, and team work review by each member. Suggested Progress (Starts) Weeks 1 and 2 Understand assignment brief Form your pair Develop working plan and assign roles Become familiar with Autocad Weeks 3 and 4 Inspect site using identified resources Become familiar withsite geometric features Become familiar with concept layout Become familiar with required workmanship Weeks 5 and 6 Start to prepare base plan including features Start to prepare longitudinal profile of natural surface and features Weeks 7 and 8 Start to prepare control line horizontal alignment on plan Start to prepare control line vertical alignment on profile Become familiar with bridge concept elevation drawing Weeks 9 and 10 Start to prepare plan views of T junction and X intersection Start to modify bridge concept elevation drawing to be true to your control line design Weeks 11 and 12 Start to write design justification memorandum Start to compile all components of your design including checking of consistency Week 13 Finalise your design justification memorandum Finalise all aspects of your design Submit your design including memorandum