Piling / Foundation works (your complete foundation partner)

ROTARY BORED PILINGs

Rotary Bored Piles are usually employed for large commercial and industrial developments, public buildings, transport infrastructure, and marine projects. Bored piles are often larger in diameter than conventional continuous flight auger (CFA) piles and are used to support greater loads, overcome underground obstructions, penetrate ground too hard to bore using a continuous flight auger or create piles with a cut-off level beneath the platform level. As the rotary bored technique enables the reinforcement to be added into the open bore rather than into the ready poured concrete, as in CFA, it has the distinct advantage of allowing the cage to be the full depth of the pile.

The standard method for construction is to screw a temporary outer steel casing/sleeve into the ground.  At the same time, an auger /digging bucket or core barrel is used to excavate and ‘muck out’ inside the casing.  When the pile toe level has been achieved, a reinforced steel cage is introduced into the bore, and concrete is poured by means of a ‘tremie pipe to the required level. The temporary segmental steel casing can then be withdrawn by the rig or a casing oscillator and used at the next pile location.

GTGABDO LTD. has developed specialist expertise in delivering large, complex, and technically challenging projects.

In addition to the basic technique, GTGBADO Ltd utilizes specialist proven adaptations to suit more challenging ground conditions, site requirements or programs, such as rock-socketing to achieve high capacity loads, the use of permanent casing or geotextile socks to prevent ‘wash-out’ and loss of concrete, the utilization of drilling fluids such as bentonite and vinyl-polymer where the bore requires support during excavation, and also the employment of specialist air-driven ‘Down-The-Hole’ hammers (DTH) to get through harder rock types.

Our early involvement in projects has often resulted in significant savings in both program and cost for many of our clients.  Our success on these projects has led to a very high percentage of repeat business and an unrivaled reputation for quality, safety, and value-engineered solutions.

Advantages of Rotary Bored Piles

• Accommodate large loads

• Greater depths possible up to 60m

• Suitable for all soil types

• Wide variety of sizes up to 3m in diameter

• High levels of accuracy

• Suitable for marine works

• Allows the use of complex pile testing instrumentation

• Better suited for the use of full-length reinforcement cages as the cage is placed into the bore before concreting

• RTB rigs are more powerful and capable of boring in challenging ground conditions

• RTB rigs have a wide range of augers, digging and coring tools which can be changed relatively quickly to overcome a wide variety of ground conditions and obstructions

CFA PILING

What is CFA Piling?

The Continuous Flight Auger (CFA) technique is one of the quietest piling solutions available and is virtually vibration-free, making it ideal for working in close proximity to existing buildings or in environmentally sensitive areas. CFA piles can also be installed relatively quickly and economically without the need for casing, bentonite, or polymers, in both cohesive materials such as clay and non-cohesive material such as sand, gravels, and glacial tills. CFA piles are suitable for both load-bearing piles and for contiguous or secant retaining walls.

Basic Technique

A hollow-stemmed continuous flight auger is rotated into the ground to the required depth or degree of resistance. As the auger is withdrawn, concrete is pumped down the hollow stem at a specific flow rate and pressure to maintain the pile shaft from collapsing, or voids forming in the concrete, this process is crucial to the success of the pile and is monitored closely by the rig operator by the use of computerized instrumentation. After the auger is extracted and the pile concreted to the surface, a reinforcing cage is then inserted into the wet concrete by excavator or by using a cage-vibrator for longer cages.

Our fleet includes CFA rigs weighing between 25 and 155 tonnes which are capable of installing piles up to 35m deep, and with pile diameters ranging from 350mm to 1200mm.

GTGABOD LTD. have an experienced team of design engineers in-house who can work promptly and proficiently to overcome unforeseen site conditions (as they arise) to mitigate potential delays. Further, we can review geotechnical information at any stage of the project and value-engineer the design to reduce costs or program duration.

Advantages

• Minimal disturbance, hence limited risk of damage to adjacent structures

• No casing is required

• Suitable for all soil types

• Ideal for retaining walls

• Speed of installation

Instrumentation

All GTGABOD’s CFA rigs are fitted with the latest generation NDT piling rig computer systems – a fully integrated interactive tool with a touch-screen interface in the rig cabin which enables our CFA rig operators to monitor and accurately control all aspects of the pile construction consistently and to specific quality-controlled specifications. As each pile is completed, the pile data is transmitted from the rig via a cell phone network to the ‘cloud’ for review on a net-connected device, thereby enabling real-time quality control. The system provides instant data on important parameters such as:

• Auger depth

• Auger rotations

• Penetration speed

• Rotary torque

• Crowd winch force

• Extraction force

• Extraction speed

• Concrete pressure

• Concrete flow

• Total concrete volume pumped

• Productivity

Cased CFA Piling

Cased CFA combines the benefits of a rotary and a CFA solution proving particularly beneficial and effective when installing larger contiguous and secant-piled retaining walls. The single flight auger allows much faster continuous drilling whilst the casing helps to keep the pile vertical, within tolerance and in the case of a secant piled wall, watertight. The rotary drive units for the casing and the augers are connected but rotate in opposite directions, simultaneously drilling them into the ground. As in a traditional CFA technique, the spoil travels up the auger string and is deposited from the top of the casing into a series of telescopic tubes safely expelling it directly into a disposal vehicle, a skip, or to a holding area at ground level.

Concrete is then pumped through the hollow stem of the auger as it is retracted and the cages are installed once the pile is complete.

DISPLACEMENT PILING

Bored displacement piles are usually employed in ‘brownfield’ sites where the cost of removing spoil off site is expensive.  While the technique is relatively new it is now widely considered to be an acceptable, and often attractive, alternative foundation solution. The piles are produced and cast in-situ with minimal creation of spoil using low noise and vibration techniques.

Bored displacement piles can be constructed to depths of up to 26m in a range of diameters. Piles can be designed to carry lateral and tension loads as well as bending moments.

Ground Conditions

The bored displacement piling technique is suited to a wide range of soil types, particularly very loose and loose to medium-dense granular materials (sands and gravels) and cohesive materials (clays and silts) which are very soft, soft, firm or even stiff. Piles can be constructed through alluvial deposits and filled ground. The absence of spoil from the operation makes this technique ideal for contaminated sites.

Basic Technique

A hollow-stemmed displacement auger is rotated into the ground, displacing the soil laterally and resulting in a localized, increased relative density and strength around the pile (depending upon soil conditions). This avoids the need to deal with large volumes of spoil at the surface of the ground. Just as in CFA piling, as the auger is withdrawn, concrete is pumped down the hollow stem while the operator monitors the concrete pressure and flow rate, forming a shaft of liquid concrete to ground level. A reinforcing cage is then inserted into the wet concrete using a ‘cage-vibrator’.

Advantages

The bored displacement pile is suited to a range of soil types and can improve the strength of the soil during its installation.

Minimal spoil production leads to reduced costs for site plant, haulage, and disposal and provides an ideal solution for brownfield sites where contamination may be an issue. Production can be faster also because of the absence of spoil to clear from the head of the pile.  On contaminated sites, the risk associated with handling spoil is eliminated. This method is also attractive where there are local restrictions on the amount of construction traffic permitted on the surrounding roads and highways.

The improvements to the soil lead to a more efficient pile design (when compared to other pile types of bored pile), due to the greater pile capacity and load transfer to the surrounding soils.

Improved load transfer to the surrounding ground is achieved through an enhanced shaft capacity and a thick concrete ‘thread’ is formed in the construction process that facilitates the load transfer from pile core to soil. This is achieved through the creation of an increased diameter/surface area and the bearing effect of the thick threads formed.

Micro Piling 

Micro Piles

A mini-pile generally has a diameter of between 100 and 300mm and can extend to depths of over 50m.

What is it used for?

Construction of high-capacity small-diameter piles

Installation of piles under existing structures such as bridges or even overhead power lines

Underpinning or strengthening of existing structures both externally and/or internally

Slope-stabilisation works

Construction of propped or unpropped retaining walls

To resist hydrostatic uplift pressures

Upgrading existing floor slabs

Basic Technique

GTGABOD LTD. have a fleet of mini-pile rigs ranging in size from 2.5 to 18 tons. This equipment is extremely versatile and the smaller rigs can operate within buildings. Piles may be vertical or raked and can also be pressure-grouted for increased capacity if required. Drilling techniques include cased, auger and rotary-percussive. Either a reinforced steel cage, steel circular hollow section or a centralised steel reinforcement bar may be used. GTGBAOD can offer high-capacity mini piles with safe working loads of up to 1200kN.

Advantages

Ability to bore through variable and difficult ground conditions e.g. masonry or existing concrete foundations

Construction within restricted working areas and/or low headroom

Working within existing premises with minimal disruption to other operations

Low vibration

Permanent liners can be incorporated into the solution for installations in very soft ground conditions.

RESTRICTED ACCESS PILING

GTGABOD LTD. has successfully completed some of Nigeria’s most challenging ground-engineering projects. Quite often these projects have a bespoke nature and are so specialized that utilizing standard plant and equipment is not possible.

As an Indigenous construction company that has a deep understanding of the Nigeria terrain, many years of experience, innovation, and expert knowledge of drilling and piling methods have been retained and developed. This industry-leading expertise and knowledge have resulted in GTGABOD Piling becoming the ‘go-to’ contractor for highly specialized piling and drilling projects.

In addition to a wide range of standard restricted access machines, GTGABOD has adopted and modified several piling rigs specifically for projects where the site constraints have imposed more extreme restrictions.

GTGABOD can offer a wide range of plant and equipment and industry-leading experience to ensure our client base receives the most cost-effective solution for the most demanding projects.

In areas where the ground is particularly poor, time and money can be saved by using a smaller piling mat, or a smaller temporary working platform. GTGABOD can deploy a powerful, versatile lightweight rig to carry out the works safely and efficiently.

ODEX PILING

Drilled Piling

Drilled piles are commonly used on projects where underground obstructions are expected/encountered or if the designed pile is required to penetrate dense or rock strata to form a pile or rock socket. The type, diameter and depth of the pile will be influenced by the soil/rock type, the load or tension required and the constraints of the project on the piling method.

Odex Piling

GTGABOD are the most experienced ODEX specialist in the Nigeria; coupled with an extensive range of equipment we are able to offer a distinct advantage over competitors at tender stage and help to reduce costs and duration of works. 

Basic Technique

The term Odex is an abbreviation for Overburden Drilling EXcentric. Odex piling is a drilling method suitable for boring through boulders and rock strata.

A specialist heavy duty drill ‘string’ is lowered into a steel tube or outer casing. Once drilling starts, the Odex drill bit quickly cuts ahead of the steel casing which enables a number of ‘wings’ on the bit to open out. The bit can now drill a hole with a diameter slightly greater than that of the steel casing. At the same time the ‘shoulder’ of the drill bit hits against a ‘shoe’ on the inside of the casing. This allows the steel casing to be hammered down simultaneously and closely behind the drill bit. High pressure air discharged through flushing holes in the face of the drill bit push the drill arisings back up the casing to be caught by a ‘shroud’ and discharged into a skip or other means of spoil collection.

Once the desired depth has been reached, the drill bit is turned once in reverse. The ‘wings’ fold back in allowing the drill to be withdrawn back up inside the casing – leaving the casing in place.

The pile is then filled with concrete or grout after a reinforcement cage or solid bar is placed.

The casing tube can either remain permanently or be removed after the concrete or grouting process has been completed.

Odex piling is used for

• Drilling through boulders / obstructions / rock strata

• Installing either temporary or permanent casing

• Drilling rock-sockets

• Pre-drilling for CFA projects

• Wide variety of sizes available

Construction

Our suite of integrated construction services ensures the highest degree of quality, safety, efficiency, and innovation on your projects.

Since its inception in 2008 GTGBAOD has been responsible for the design, planning, and delivery of over 500 residential and commercial buildings in Nigeria, especially in Lagos.

Our team is able to work with you to balance the economic, social, and environmental challenges to create the best cost and quality outcomes.

SOIL TESTING 

Soil testing from GTGABOD – assess the suitability of the soil for your construction project with vital data for informed decision making and planning.

The quality of the soil on your site plays a key role in your construction projects. As a result, you need to identify the characteristics of the soil to determine its ability to support your structure. Soil testing from Gtgabod enables you to assess the suitability of the soil, providing you with vital data for informed decision-making and planning.

WHY USE SOIL TESTING FROM GTGABOD FOR YOUR CONSTRUCTION PROJECTS?

Our soil testing services examine your soil’s chemical and geotechnical properties, enabling you to:

• Determine the suitability of the soil and assess whether it can accommodate your construction project

• Identify the different types of soil on your site and their location

• Test your soil for strength, density, compaction, contamination, organics and sand content, and assess their impact on your construction project

• Gain the data you need to compile technical and safety data reports to support planning permissions and license applications

• Get precise results and observe the development of the soil throughout your construction project for maximum quality and safety

TRUSTED SOIL TESTING FROM A LEADING PROVIDER

As a leading provider, we are fully accredited and qualified to perform soil testing according to national and international quality standards. Plus, with our unrivaled network and experience, we are the first choice for civil engineering contractors, consultants, manufacturers, and government agencies across Western Nigeria.

Our soil testing services include:

• Complete laboratory testing for shear strength, compressive strength, consolidation, permeability, foundation load, soil index and moisture/density

• Software analysis

• Technical support and consultancy