Bridges, Roads, and Highways

The design and construction of bridges, roads, and highways requires a deeper understanding of various environmental and international standards/regulatory know-how, careful planning, and execution. From feasibility studies to planning, engineering design, procurement, construction, and post-construction assessments, engineering expertise is required to ensure optimal efficiency and safety, while minimizing costs and environmental impacts. Our in-house professionals have planning, design, environmental, geotechnical, and surveying capabilities. We ably assemble highly qualified teams with the right specialties and backgrounds to match our clients’ needs and requirements.  Our expertise in roads and highways is built on years of experience working with the ever expanding road networks across the country.

Our extensive experience includes the design and construction of new roads and rehabilitation and upgrading of existing roads. Our transportation specialists support a variety of construction environments, ranging from rural and urban roads, railroads, ports, terminals, barge landings, and community-based constructions. Our diversified experience and expertise in the wide range of geotechnical services enables us to provide end-to-end solutions for bridges and civil structures from investigation, testing and instrumentation, engineering design, and construction support, to monitoring, maintenance, and rehabilitations. Our services include feasibility studies, conceptual design, geometric design, bridge structures, stormwater management, materials investigation, surfacing and layer works design, pavement and management systems.

Bridge Engineering.

A bridge is a structure built to span a horizontal gap to carry a road, railway, pathway, canal, or pipeline over an obstacle such as a river, gorge, valley, or other obstruction.

There are several types of bridges, among them;

Beam bridges. These are the simplest bridge type normally consisting of one or more spans, supported by pier or abutment at each end. Beam bridges are usually constructed of RCC or steel or a combination of both RCC and steel.

Arch bridge. As the name suggests, the arch bridge consists of a curve-shaped abutment at each end. Generally, the roadway of the bridge lies on the arch structure.

Truss bridge. The superstructure of the truss bridge is constructed by using trusses which are composed of many small elements forming triangular trusses. Truss is used because it is a very rigid structure and it can transfer the load from a single point to a much wider area.

Tied-arch bridges. These can be built on elevated piers or in areas of unstable soil. One more positive attribute of this type of bridge is that it does not depend on horizontal compression forces for its integrity, which allows them to be built off-site and then transported into place.

Suspension bridge. The deck slab is suspended using ropes, chains, or high tensile strength steel cables. The roadway hangs from massive steel cables which are draped over two towers and secured by anchors on both ends of the bridge. The anchors are made from solid concrete blocks. The cables transfer the loads into compression in the two towers. Usually, this type of bridge can span 2000 – 7000 feet.

Cantilever bridge. This is constructed using a cantilever span. The span is supported at one end and the other end is open. Usually, two cantilever parts are joined to make the roadway.

Cable-stayed bridge. These are similar to suspension bridges as they also use cables but in a different form. They consist of fewer cables and the height of the towers is much greater than the suspension bridge.

We offer high quality consultancy and construction services in bridge engineering, including;

• Bridge asset management and condition assessment,
• Feasibility study, engineering design, and construction of bridges,
• Bridge infrastructure digitalization,
• Bridge owner’s engineer,
• Bridge planning,
• Bridge seismic design,
• Bridge monitoring i.e. slope stability analysis and provision of remedial design options for bridges showing signs of failure,
• Engineering design and construction of flyover bridges, underpasses, overpasses (overbridges), pedestrian bridges,
• Engineering design and construction of foot bridges (cable bridges),
• Geotechnical services for bridges and civil structures,
• Design and installation of sheet piles for bridge abutments,
• Engineering design and installation of bridge abutments, bridge piers, bridge decks, wing walls, retaining walls, and bridge embarkments,
• Bridge inspection i.e. bridge deck deterioration and rebar corrosion to effectively prioritize repair efforts,
• Bridge deck evaluation i.e. evaluate deterioration, corrosion of reinforcing steel, and delamination of asphalt and concrete,
• Bridge condition assessments detecting subsurface defects, such as delamination, corrosion, or voids, allowing for timely repairs and effective maintenance planning,
• Bridge inspection and assessment,
• Bridge scour analysis and mitigation measures.

Roads and Highways Engineering.

A road is a thoroughfare, route, or way on land between two places that has been surfaced or otherwise improved to allow travel by foot or some form of conveyance, including a motor vehicle, cart, bicycle, or horse. Roads have been adapted to a large range of structures and types in order to achieve a common goal of transportation under a large and wide range of conditions. The specific purpose, mode of transport, material and location of a road determine the characteristics it must have in order to maximize its usefulness.

Roads and highways solutions must be long-term, sustainable, and cost effective, from local access roads to major urban and rural strategic routes. Improving safety, easing congestion, and extending street and highway life are always top priorities for the government. Good road networks, especially paved roads have immense positive impact as they improve mobility of vehicles, reduce traffic congestion and hence travel time, reduce vehicle wear and tear hence reduced maintenance costs, lead to reduced dust levels, increase in value of land and property along the roads, increase in business opportunities, call for street lighting, and as well improve scenic beauty and aesthetics. Given the scale and duration of road network development, the strength and robustness of the scheme’s initial planning is undeniably important.

There are different types of roads based on different classifications. Out of all, road classification based on speed, accessibility, and materials used is the most crucial.

Based on the speed and accessibility.

• Freeways,
• Expressways,
• Highways,
• Arterials,
• Local Streets,
• Collector Roads.

Based on the Materials used.

• Earthen roads,
• Gravel roads,
• Murram roads,
• Kankar roads,
• Water bound macadam roads (WBM),
• Bituminous roads,
• Concrete roads.

Earthen Roads.

Earthen roads are very common in the countryside and few traffic areas. These roads are constructed by means of putting soil with fine gravels in the pathway to give compaction to the road. These roads are very successful in areas where there is a low ratio of rainfall. While in the areas of high rainfall, these roads become troublesome. These roads are successful in the sandy and stony areas, where the rainwater does not mix with soil to form mud.

Gravel Roads.

Like earthen roads, the gravel road is also included in the category of unpaved roads. Like the earthen road, the gravel is scattered in the way/path of the road. The top of the road is enriched with gravel. The gravels do not allow the rainwater to form mud. These types of roads are also constructed in rural countryside areas. These roads are very cheap, easy, and less time-consuming. These roads do not need any engineering skills. These roads can be built by ordinary labor.

Murrum Roads.

A murrum soil is a mixture of soil, sand and gravels, and concrete. The construction of these roads is quite similar to the above mentioned, the earthen and the gravel road, but are different on the basis of material used in their construction.

Kankar Roads.

Kankar is the impure form of line stone. Kankar gravels, like in the murrum and gravel roads, are scattered in the way. Kankar roads are very common in the areas where limestone is easily and cheaply available. These roads, if compared to paved roads, are low-quality roads. Limestone gets easily mixed with rainwater and forms mud, which can put the traffic in trouble.

WBM Roads.

WBM stands for Water Bound Macadam. WBM roads are constructed with a stone border. The border is filled with sand mixed with soil and very fine gravel called “screening”. The stone borders are bonded tightly with the help of screening. As the top wearing surface of this type of road consists of stone gravel and border, therefore the formation of mud is less likely in these types of roads. The stone border is compacted by the rolling process. Water is poured on the WBM during the rolling process. This type of road is very successful and compacted, especially in rainy areas.

Bitumen Roads.

Bitumen road, also called asphalt road, is a very smooth and soundless road. This type of road is a masterpiece of civil engineering. The construction of this road goes through a number of complex phases. The first phase of this road is “preparation of base course”. In this phase, the irregular landscape is graded with the help of a grader machine. The landscape is once levelled, then, murrum consisting of fine gravels and soil is placed on the road. This layer is compacted by means of rollers and compactors. After compacting it well, a layer of larger border of stone is placed. The spaces of the border are filled with screening. Again, the rolling work is conducted. Water is thrown all through this process. Now the second phase starts. The second phase of the construction of the road is the placement of a bituminous coat. The hot and molten bituminous is showered on the border filled with screening. The third phase of the construction starts with the placement of a bituminous mix. The bituminous mixture consists of concrete mixed with bitumen. This layer is 3 to 5 inches thick. The layer of the bituminous mix is placed either by machines or by hands. The fourth phase of the construction of this type of road starts and ends at rolling work. The rolling work is conducted by a roller machine. The purpose of rolling is to compact the road.

Concrete Roads.

Concrete roads are constructed with the help of concrete made up of cement and stone gravels. This road is very durable and strong. Its disadvantage is that it does not provide friction between the road surface and the tires of the vehicle. This type of work is generally done in streets and small size projects.

At SANKOFA, we offer a suite of road and highway engineering related consulting and implementation services, including;

• Feasibility study, detailed engineering design, and construction of roads and highways, including national trunk roads, international trunk roads, arterial roads, feeder roads,
• Periodic maintenance, rehabilitation, and reconstruction of road networks i.e. pothole patching, patching of surface defects, edge breaks repair, drain cleaning and desilting,
• Road safety audits and black spot identification (road traffic safety assessments),
• Road condition assessments i.e. visual condition assessments, geometric assessments, structural assessments, climatic assessments, drainage assessments, traffic assessments,
• Road drainage design and drainage installation,
• Road and highway lighting design and installation of outdoor LED street lighting (double arm and single arm LED street lights/lamps),
• Engineering design of non motorized transport (NMT) route corridors,
• Installation of road safety signs and road markings i.e. regulatory and mandatory signs, warning signs, and informative signs, reflective road studs, guardrails,
• Installation of traffic calming measures i.e. humps, rumble strips,
• Road network optimization and traffic signalization,
• Geometric road design and route corridor identification,
• Materials investigation, geotechnical investigations, surface and layer works design,
• Pavement design,
• Design of borrow pits,
• Detailed engineering design of express highways, road junctions, roundabouts, intersections, interchanges, sidewalks, pedestrian footpaths, cycling lanes, parking facilities, runaways, tunnel roads,
• Feasibility study and detailed engineering design for widening, capacity improvement to dual carriage ways, and signalization of roads,
• Earthworks design, earthworks implementation, soil stabilization, grading, and compacting,
• Detailed engineering design and construction of landing sites and ferry landing jetties,
• Construction of weigh stations/weigh bridges, including High Speed Weigh-in Motion (HSWIM) lanes,
• Utility mapping and utility line relocations,
• Traffic studies and planning,
• Engineering design and implementation of intelligent transport monitoring systems (ITMS) i.e. implementation and operation of field devices, road tolling technology, managed lanes, communications, travel information, and transit technologies,
• Engineering design and installation of road signalization and road traffic management systems i.e. traffic monitoring cameras (traffic control cameras/traffic cameras), speed cameras, traffic surveillance cameras (road CCTV cameras),
• Engineering design and installation of fuel service stations and underground storage tanks (UST) for petroleum products.

We supply bridge, road, and highway related equipment and material, including;

• Thermoplastic resin powder for road marking,
• Glass beads granules for road marking,
• Highway guardrail systems,
• Bridge parapets i.e. precast concrete and steel parapets,
• Cold paint road marking machines,
• Thermoplastic paint preheaters,
• Reflective glass beads for road paints,
• Road marking cleaning machines,
• Road paint marking line removal machines/paint stripping machines,
• Road marking materials i.e. white and yellow thermoplastic road marking paint, cold solvent road marking paint, two-component road marking paint, intermix and drop on glass beads, petroleum resin and road marking tapes,
• Accessories i.e. wearing parts of machines such as glass beads dispenser, marking die shoes, side blades, rear blades, spray guns and steel brushes,
• Guardrail post drivers,
• Post drilling machines,
• Guardrail beams (roadside stainless steel barriers),
• Guardrail bolts and nuts,
• Guardrail posts,
• Impact terminals (start and end terminals),
• Mobile safety steel barriers (expandable portable barriers, crowd control barrier fences/gates),
• Guardrail end terminals,
• Guardrail spacers,
• Guardrail forming machines,
• Guardrail repairing machines,
• Guardrail delineator reflectors,
• Rockfall netting/rockfall barriers
• Pontoon bridges (floating bridges),
• PVC traffic cones/PE traffic cones,
• Road barriers (including road spike barriers),
• Weigh bridges i.e. concrete deck weigh bridges, electronic truck scales, portable axle weighing scales, above ground truck scales, pit mounted scales,
• Pile driver machines/piling machinery,
• Sheet piles,
• Portable bridges,
• Trench shoring equipment,
• Road sign retro-reflection meters,
• Convex road marking paint,
• Thermoplastic paint whiteness testers,
• Line thickness measuring instruments,
• Reflective road studs i.e. plastic and aluminium road studs,
• Rubber speed bumps,
• Road safety barricade warning tapes,
• Barricades and barriers,
• Barricade lights,
• Delineators, channelizers, and drums,
• Barricade tape, marking flags, and paint,
• Flat top surface mount delineators,
• Road safety nets/safety barrier mesh,
• Traffic marker posts,
• Highway safety bollards (retroreflective bollards, T-top traffic bollards, slope top bollards, dome top steel bollards), LED sign lighting products, highway delineators, chevron boards, hazard markers,
• Asphalt and concrete road cutters,
• Asphalt crack sealing machines,
• Crack router machines i.e. road grooving,
• Pavement marking retro reflectometers.