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Digital engineering demonstration

Urban road and drainage upgrade

One connected workflow, from survey surface to civil model, quantities, estimate, programme and cash flow. Every number on this page traces back to the same model.

Demonstration project prepared by Rabello Engineering to show our digital engineering workflow. It is not a client project. Quantities, rates and dates are illustrative.

Length

600 m urban road

Scope

Road, drainage, culvert, retaining wall

Estimate

$3.04M (illustrative)

Programme

28 weeks

Software

Civil 3D, Navisworks, Expert Estimation, MS Project

Six steps, one set of information

  1. 01

    Civil model

  2. 02

    Model quantities

  3. 03

    First-principles estimate

  4. 04

    Construction programme

  5. 05

    4D simulation

  6. 06

    5D cash flow

01

Civil model

Autodesk Civil 3D

We built the existing ground surface from survey, then designed the alignment, vertical profile and corridor for a 12 m carriageway with kerb and gutter, footpaths and 1:3 batters.

The stormwater network has 14 grade pits, a DN450 trunk line falling to a DN600 transverse culvert at CH 0+322, and a 100 m retaining wall where the road cuts into a hill. The existing DN150 water main is modelled too, so the drainage crossings can be checked early.

Civil 3D model with the surface shaded by elevation, the corridor, the stormwater network and the culvert. Profile and cross section views alongside.
Figure 1. Civil 3D model with the surface shaded by elevation, the corridor, the stormwater network and the culvert. Profile and cross section views alongside.
Longitudinal section of the main road with existing surface, design level, grades and the trunk drain invert.
Figure 2. Longitudinal section of the main road with existing surface, design level, grades and the trunk drain invert.
Cross section at CH 0+460 showing the pavement layers, kerbs, the DN450 trunk and retaining wall RW01.
Figure 3. Cross section at CH 0+460 showing the pavement layers, kerbs, the DN450 trunk and retaining wall RW01.
General arrangement plan, drawing RE-DEMO-C-101 Rev B, produced from the same model.
Figure 4. General arrangement plan, drawing RE-DEMO-C-101 Rev B, produced from the same model.

02

Model quantities

Autodesk Navisworks Quantification

Quantities come straight from the model instead of being scaled off drawings. Cut and fill are measured between the existing and design surfaces, pavement layers from the corridor, and pipes and pits from the network.

The earthworks nearly balance: 4,165 m³ of cut against 4,096 m³ of fill, leaving 69 m³ to spoil. The mass haul line shows where material needs to move along the job.

Quantification workbook linked to the model. The cut and fill depth map is shown in the viewport and the selected DN450 pipes are highlighted.
Figure 5. Quantification workbook linked to the model. The cut and fill depth map is shown in the viewport and the selected DN450 pipes are highlighted.
Bulk cut
4,165 m³
Fill, place and compact
4,096 m³
Subbase DGS40, 250 mm
1,180 m³
Base DGB20, 250 mm
960 m³
AC14 wearing course
7,200 m²
DN300 RCP
420 m
DN450 RCP
180 m
Grade pits
14 No.
DN600 transverse culvert
48 m
Retaining wall concrete
185 m³

03

First-principles estimate

Expert Estimation

Each model quantity is priced from its resources: crew hours, plant, materials and subcontract quotes, at a stated production rate. The DN450 pipe, for example, is laid at 24 m a day, which builds up to $584.80 per metre.

Because the estimate is linked to the quantity source, a design change flows through as a quantity change, not a re-measure.

Estimate by package with the resource build-up for the DN450 pipe and the tender summary.
Figure 6. Estimate by package with the resource build-up for the DN450 pipe and the tender summary.
Direct costs
$2,090,459
Preliminaries
$604,100
Overheads and margin (8%)
$215,565
Risk and contingency (5%)
$134,728
Tender sum, excl. GST
$3,044,852

04

Construction programme

Microsoft Project

The programme follows the methodology behind the estimate: the same crews, production rates and staging. It runs 28 weeks, from Monday 2 February to Friday 14 August 2026.

The critical path runs through stripping, bulk earthworks and subgrade, then subbase, base, seal and asphalt. The culvert and retaining wall sit off the critical path with float, which makes them useful for levelling crews.

Construction programme with the critical path in red, the tender baseline in grey and the status date in green.
Figure 7. Construction programme with the critical path in red, the tender baseline in grey and the status date in green.

05

4D simulation

Autodesk Navisworks TimeLiner

Each programme task is linked to a set of model elements, so the sequence can be played back day by day. This is where staging problems show up: plant working next to the wall pours, traffic switches, and the drainage crossings near the water main.

Figure 8 shows week 18, with the subbase going down, the wall stem being poured and the eastern drainage still in progress.

Video. The full 28-week TimeLiner simulation, from site establishment to practical completion. Green shows work under construction, yellow shows temporary works such as the site compound and barriers.
TimeLiner simulation on Thursday 4 June 2026. Active work in green, finished work in its model colours.
Figure 8. TimeLiner simulation on Thursday 4 June 2026. Active work in green, finished work in its model colours.
Stormwater pipe laying, the activity shown in progress in the simulation.
Figure 9. Stormwater pipe laying, the activity shown in progress in the simulation.AI-generated illustrative image, not a photograph of the project.

06

5D cash flow

Cost dashboard linked to the model and programme

Spreading each estimate line across its programme task gives a planned cash flow. Spend peaks in July 2026 at about $874,000, when the asphalt and kerbs go down.

Once work starts, planned, earned and actual cost can be tracked against the same baseline. At week 18 the example shows a schedule index of 0.96 and a cost index of 0.98.

5D dashboard: S-curve, monthly spend, cost by package and the model coloured by package.
Figure 10. 5D dashboard: S-curve, monthly spend, cost by package and the model coloured by package.

What the model describes

Illustrations of the finished road and the culvert outlet. Both are AI-generated images, included to show the kind of works the model represents.

Completed road with kerbs, footpaths, culvert headwall and retaining wall.
Figure 11. Completed road with kerbs, footpaths, culvert headwall and retaining wall.AI-generated illustrative image, not a photograph of the project.
DN600 culvert outlet with headwall, wingwalls and rock scour protection.
Figure 12. DN600 culvert outlet with headwall, wingwalls and rock scour protection.AI-generated illustrative image, not a photograph of the project.

Use as much or as little as the job needs

Many tenders only need model quantities and a solid estimate. Others benefit from 4D staging or a cost-loaded programme. We will tell you which is worth it before any work starts.

Digital engineering services