Motorways & Interchanges Task 2

Please Note - You are not required to input this information into the Portfolio document - simply show your calculations and summary costs here and submit all as one document

Project 2 - Motorway and Interchange Calculations

You are the head of the Queensland Transport Department, and are reviewing the costs of a new regional 4 lane motorway to connect a newly discovered Lithium mine to coastal port facilities. You need to review the costs of 2 Motorway design options based on "whole of Life" total economic costs, together with a review of 2 interchange design options based on the construction cost of each type of interchange .

Part A - Motorway Options

Your Motorway is designed for a 100 year life, with Average Annual Daily Traffic (AADT volumes) designed for 10,000 vehicles per lane, with 10% of these heavy trucks to carry the Lithium,

Note that even though the heavy trucks, comprising B double articulated rigs, are a relatively small percentage of total traffic, they are significantly penalised in speed and fuel for grades of 5% and tighter bends in the road, as they consume more fuel both in extra work uphill, and in engine braking downhill.

Other modes of transport are relatively unaffected by these 5% grades and tighter curves, so we can neglect the cost of trips with these vehicles, as they are effectively the same for each version of the Motorway route,

For your "whole of life" costing of the Motorway options, this will include :

• The initial build cost of each Motorway
• The ongoing maintenance cost to upkeep each Motorway in good condition, and
• The difference in extra cost imposed on heavy truck transport between M1 and M2 ($30 per trip)

You have a choice of 2 options for your Motorway route :

M1 - up & over the mountains as the most direct route - 100km long, with 5% grades up and down (vertical geometry), several tighter curves (horizontal geometry), heavy truck speed limited to just over 71 km/hour average due to the road design, with a road build cost of $10m per km (incl all 4 lanes).

The heavy truck cost per 1 way trip is $330 (comprising fuel $200( 2 litres per kilometre), truck maintenance $60 ( $0.5 per kilometre with 20% extra for steep curvy terrain), driver salary $70 (at $50 per hour))

M2 -around the mountains to avoid the steep grades and tight bends - 150km long, flat to1% gradient, sweeping curves, 100km/hr average heavy truck speed, with a road build cost of $8m per km (incl all 4 lanes).

The heavy truck cost per 1 way trip is $300 (comprising fuel $150 (1 litre per kilometre), truck maintenance $75 ($0.5 per kilometre for flat terrain), driver salary $75 (at $50 per hour))

You are to show your calculations for the following in the Table below :

1. Road build cost of each Motorway
2. Road maintenance cost over 100 years, at 2% x build cost per year, divided by a factor of 6 to get the value of this item in today's dollars (this denotes today's cost with 2.6% compound inflation)
3. Extra cost of heavy trucks per year over 100 years, divided by a factor of 6 to get the value of this item in today's dollars, for the M1 (this denotes today's cost with 2.6% compound inflation)
4. Based on the sum of the above 1 to 3, nominate your choice of M1 or M2 for construction, based on the comparative "whole of life" cost of each.

Cost Item	M1	M2
Build Cost $m
Maintenance Cost $m
Extra Heavy Truck Cost $m		Nil
Total Life Cost $m
Choice

Part B - Interchange Options

At several points along your Motorway above, you need to build a series of basic Interchanges with the many 2 lane minor cross streets which are intersected by the major 4 lane divided Motorway. Your designers have drawn up 2 options for either a Partial Clover Leaf or a Diamond patterned Interchange.

Each interchange will be elevated relative to the Motorway, and connected by a 2 lane flyover bridge linking each side of the interchange, thus maintaining the continuous flat straight grade on the Motorway, with minimal interference to Motorway traffic.

You will make your decision as to the best choice of interchange based on the construction cost of each type. The Motorway itself, and the 2 lane flyover link bridge, are excluded from the calculations as these are common elements of both designs. Each interchange enables a 5 metre clearance from the underside of the flyover link bridge to the Motorway pavement.

Partial Clover Leaf Interchange

Comprises 1 clover leaf on each side of the Motorway, including :

1 x 55 metre radius single lane elevated circular exit ramp bridge, with concrete piers / I beams / deck on a 40km/hour continuous 2% grade from Motorway to flyover

1 x 90 metre long straight single lane elevated 7% grade flyover exit ramp bridge

1 x 130 metre curved Motorway exit ramp on compacted natural ground

Diamond Interchange

Comprises 1 roundabout on each side of the Motorway, including :

1 x 35 metre radius circular roundabout on elevated compacted ground

2 x 50 metre long Motorway exit & entry ramps on graduated compacted ground

Construction Costs

Bridge components $1.5million per 100 metres run for single lane, incl concrete piers / I beams / deck

Single lane road on compacted natural ground $0.25 million per 100 metres

Earthworks for elevated compacted ground $50 per cubic metre

Construction Calculation Help

• 55 metre radius elevated circular bridge has circumference 350 metres
• 35 metre radius circular roundabout has circumference 220 metres

You are to show your calculations for the following in the Table below :

Interchange	Cost Item	Calculations Total metres for Bridges & Roads Total metres cubed for Earthworks	Clover Leaf	Diamond
Cost Each M or M3 $m	Total Cost $m	Cost Each M or M3 $m	Total Cost $m
Clover Leaf	55m Radius Circular Motorway Exit Ramp Bridge				NA	NA
90m Straight Flyover Exit Ramp Bridge				NA	NA
130m Curved Exit Ramp Road on Ground				NA	NA
Diamond	35m Radius Circular Roundabout Earthworks on Compacted Ground		NA	NA
50m Motorway Entry & Exit Ramps Earthworks		NA	NA
Single lane Road on top of Earthworks		NA	NA
NA	Total Cost of Each Type of Interchange $m	NA	NA		NA
Choice of Interchange Type

(For your own information, and NOT as part of this exercise, the basic cost breakdown of the construction costs above generally include : Design + Prelim + Project Management 7% / Site Preparation 8% / Pavement Construction 60% (or Bridge piers 20%, beams 20%, deck 20%) / Kerb + Drainage 15% / Service Alterations 5% / Footpaths + Landscaping 5%)