Construction world best projects awards 2022 – civil engineering contractors section

Construction world best projects awards 2022 – civil engineering contractors section

This civil engineering construction project involved the stabilisation of cut slopes on the eastbound side of the N2, Section 2, between km 12.06 and km 12.31, at Sir Lowry’s Pass, near Somerset West in the Western Cape.

Client: South African National Roads Agency (SOC) LTD
Contract value: R27,000,000

Overview of the Project

Motivating Facts

This civil engineering construction project involved the stabilisation of cut slopes on the eastbound side of the N2, Section 2, between km 12.06 and km 12.31, at Sir Lowry’s Pass, near Somerset West in the Western Cape.
The design was undertaken by Zutari’s Cape Town geotechnical and highway teams and Naidu Consulting were appointed to oversee the project management and construction monitoring aspects.
Civils 2000 (Pty) Ltd of Cape Town partnered with GeoCiv (formerly Mega Pile Inland) to form the C2KMPI Joint Venture. These teams brought more than 50 years of combined experience to the project.
The scope of works included the stabilisation of 250m of road cutting on Sir Lowry’s Pass. The 13m high cuttings were unstable and there had been many instances of rock falls endangering the passing traffic.
The existing road accommodates two lanes in each direction and was reduced to one lane in each direction to provide working space during the soil nail drilling operations. The work zone was further protected by concrete NJ barriers with access into the work zone strictly controlled by the dedicated traffic management subcontractor.
The initial activities involved the clearance of alien and loose vegetation and debris from the work faces and the barring down of loose boulders and rocks from the cut faces. The drilling and installation of soil nails and small diameter drain pipes followed and was completed by Civils 2000’s JV partner, GeoCiv.
Once the soil nailing had been completed GeoCiv moved offsite and Civils 2000 continued with the construction of 100m of 2m high gabion in Zone A along the toe of the slopes, 90m of gabion buttresses ranging in height from 11m to 13m. GeoCiv installed and grouted 84 15m long soil nails and 488 10m soil nails.
Plates were installed as work progressed with the gabions.
The work was completed by the construction of a stone pitched open drain along the top of the slope to intercept runoff, the installation of drainage chutes, channels, and drainage structures and the revegetation of areas damaged by the works.
This project presented several unique challenges in that the existing road width had to be reduced to achieve the drilling and yet traffic flows were to be maintained during the works. In addition, the nature of the work required thinking ‘out of the box’ to solve the problems of access to high steep slopes and working on the slopes in dangerous elevated positions while eliminating risks to those below, including traffic. These challenges were met and the project completed very successfully.

Construction Innovation Technology

The removal of loose boulders from the upper reaches of the slopes presented a challenge because access and the safety concerns. Access was difficult due to the steep terrain and because there are no access tracks above the cutting. An innovative solution was arrived at by employing rope access experts. Establishment of access scaffolding from road level to the upper slopes provided access to the top of the cuttings where abseiling lines were installed. Catch walls with water barriers were installed along the mountain ridge. The climbers were able to hook in to the lines and descend to the cut faces where they dislodged the loose boulders and material. At the bottom of the cuttings the side drains were temporarily filled with gravel, rubber mats were placed on the road shoulder to prevent damage to the existing surface and a continuous line of concrete New Jersey barriers was installed along the edge of the live lane nearest to the slopes. This provided a solid barrier that ensured no boulders or debris made it onto the live carriageway. The climbers were equipped with harnesses and climbers helmets and were able to move freely around the cut faces barring down the boulders.
To enable construction of the stone pitched drains high up the slope we utilized a cargo netting system to transport 2 tons of gabions stone at a time to a height of 36 meters from the road surface and up 20 meters away from crane.
To assist with the requirements of 24-hr traffic management the traffic accommodation team utilised Dashcam video devices to capture a full record of traffic conditions on site at all times.

Corporate Social Investment

SANRAL are committed to promoting the sourcing of local services and the participation of women and youth through subcontracting, training and employment on road construction and maintenance projects across South Africa. To assist that process SANRAL provided a 14-point plan for structured engagement with stakeholders and local communities. In addition, both Civils 2000 and GeoCiv both have substantial experience of working with local communities and the site management team worked with an existing local project liaison committee (PLC) and project liaison officer to identify opportunities for local SMMEs and job opportunities.
For this project a two-month mobilisation period was provided by the client at the beginning of the project to allow time for engaging with the local communities, negotiating work packages with local SMMEs and appointing workers.
Despite this contract requiring a large proportion of the work to be done by specialists a number of jobs were created with 40 people from the local Sir Lowry’s Village and Lwandle communities employed (17 female, 23 male), of which 28 were youth appointments.
Another positive contribution to the upliftment of the local labour force was achieved by first undertaking a skills assessment from which training needs were identified and a structured skills development plan put into action. Training was provided for flag-persons (17), banksman (1) and three workers were given training in first aid, basic firefighting and the responsibilities of health & safety representatives. In addition to this training Civils 2000 sent five ‘Go for Gold’ students on first aid and health & safety representative training courses.
SANRAL provided further training opportunities for the local community through onsite training in environmental aspects by the Environmental Control Officer (ECO), providing first aid training (8), basic firefighting (10), stone pitching (12), brush cutter operations (11) and arranged for 12 places on a ‘Manage Personal Finances’ training course.
For local SMMEs five subcontract work packages were tendered by Civils 2000 and approved by the client for award. These five work packages were successfully completed by two 100% black female owned SMMEs, two 100% black owned SMMEs and a 51% black owned SMME.
Ultimately 29% of the contract spend went to targeted enterprises and 6% to local labour, exceeding the Client requirements.

Design Innovation

C2KMPI JV were not required to carry out design of any permanent works. Designs required were for temporary works only although the large access scaffolding was significant and risks from strong winds and falling risks presented some challenges to the scaffolding supplier.
Consideration of Environmental Impacts
SANRAL appointed an Environmental Control Officer (ECO) who conducted frequent environmental site audits and monitored the impact of construction activities and compliance with statutory requirements. In addition to these duties the ECO also trained workers on various environmental aspects including environmental impacts (actual or potential) caused by work activities and prevention and mitigation measures.
C2KMPI JV appointed a project Designated Environmental Officer (DEO) from Civils 2000 to monitor environmental impacts and ensure implementation of the requirements of the EMP. The DEO prepared environmental method statements addressing environmental aspects and impacts of the construction work and developed impact prevention or mitigation measures to apply to the construction activities.
The DEO then ensured controls were in place for waste generated by the construction activities and site offices, use of construction water, the impacts of vehicles and construction plant, erosion following site clearance and excavation, water pollution from runoff, preparation of an emergency procedure for controlling spills, maintenance of spill containment kits, and monitoring noise and dust from the drilling rigs.

Health & Safety

The risks from rock falls, falls from elevated positions and live traffic were well managed on site. Ultimately only one medical injury case was recorded and 20 motor vehicle accidents – 17 inside road closure, 3 outside lane closure and of the 20 recorded as MVA 3 of these were in fact truck breakdowns.
Time, Cost and Quality
The initial contract duration was extended due to additional work required towards the end of the contract. The critical path for this project initially flowed through the soil nailing operations and subsequently the construction of the gabion buttresses. Projected completion of 29/07/2022 was pushed out slightly to 02/08/2022 due to physical site constraints and the road was fully open by 12/08/2022.
The Civils 2000 quality management system was adopted by the JV teams and applied to the site works and construction management processes for the project. A Quality Plan was developed for the project and approved by the Engineer. The basic approach involved development of detailed method statements for each activity. Quality control inspections were undertaken and the completed work inspected by the RE for acceptance on behalf of the client.

Risk Management

The project risks were addressed prior to commencement with a full risk assessment and determination of mitigation measures developed. A risk register was prepared and the risks to achieving the required milestones and standards, health, safety, environment and the achievement of the employer’s considered by the site team.
With a pre-construction ADT of 14,566 vehicles per day the disruption to and safety of road users was a major risk and the provision of concrete NJ barriers ensured the live lanes were kept clear and vehicles were not at risk of being struck by boulders. Rock falls and debris coming off the slope and endangering the safety of workers and road users or causing damage to vehicles and construction plant.
The stability of the existing slopes was a risk uppermost in the site team’s assessment of risks and the Engineers had identified problem areas in three of the five construction zones.
With the N2 to remain open to traffic at all times, albeit with occasional lane closures, the possibility of slips and rock falls from the slopes was a significant hazard and the risk to passing traffic was monitored throughout the project. Working space, particularly for the telehandlers, MEWPs and the soil nailing rig, was a concern however SANRAL permitted a lane drop to provide working space for this particular activity. This caused some traffic delays but these were well managed by the specialist traffic control subcontractor.
The varying nature of the in situ material in the cut slopes also meant that runoff due to heavy rainfall had to be closely managed. This was achieved by cutting temporary interceptor drains along the top of the two cut slopes in the position of proposed permanent concrete and stone-pitched cut-off drains. The team was lucky with the weather and this risk was not fully realised.
Strong winds were a constant issue for the site teams and protocols were enforced to ensure site staff exercised care at all times, especially in exposed positions on the slopes.
Working at heights, particularly when barring down loose material was a significant risk but the installation of life lines and the rope access team meant the risks were mitigated to acceptable levels.

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