Construction technology and environmental services
| Question | Answer |
|---|---|
| What is Construction Technology? | Construction technology is a collection of various tools, applications, software and machinery that companies use during the various phases of a construction project. |
| What is Environmental Services? | Environmental services encompass infrastructure services, including sewage, refuse disposal and sanitation as well as “non-infrastructure” services, such as those related to air pollution prevention and mitigation, noise abatement and the remediation of contaminated sites. |
| Why a Chartered Surveyor has to achieve Level 3 in CT and ES? | So that they can advise and compare the cost of different technology, can suggest a cost effective technology against a costlier one for the same kind of work. |
| What is Substructure? | BCIS defines substructure as All work below underside of screed or, where no screed exists, to underside of lowest floor finishes including damp-proof membrane, together with relevant excavations and foundations (includes walls to basements designed as retaining walls). The function of the substructure is to transfer the load of the building to the ground and to isolate it horizontally from the ground. |
| What is Superstructure? | All works above ground level including frames, upper floors, roof, stairs and ramps, external walls, windows and doors, internal walls and partitions. This excludes; the substructure, finishes, fittings, furnishings, equipment and services. |
| What is Formwork? | The term ‘formwork’ refers to a temporary mould into which concrete is poured and formed so that it can set to the required shape. Traditional formwork is fabricated using timber shuttering, but it can also be constructed from steel, glass fibre reinforced plastics, plywood and other materials. |
| What is Shuttering? | Shuttering is most common type of formwork, constructed on site using timber and plywood. A special grade of plywood is necessary for shuttering, as it must be water-resistant. Shuttering is relatively easy to produce, although it can be time consuming for large structures or complex shapes. This type of temporary formwork is used when the labour costs are lower than the cost of producing re-usable formwork from materials such as steel or plastic. |
| What is Slip forming? Were would you recommend it? | Slipform is a continuous pour system involving a self-climbing formwork that supports itself on the core or shaft being constructed, moving slowly over the concrete as it is cast in a continuous, monolithic pour. It can be used to achieve tapered structures with walls of diminishing thickness and is regarded as being more economical when used for structures over seven storeys high. Normally advancing at a rate of around 300mm per hour. This can result in a smooth, continuous concrete finish without any joints, an effect which may be required where the finished structure will be visible e.g bridge pylons or a chimneys. |
| What is Jump forming? Where would you recommend it? | Jumpform is characterised by progression in a series of steps or ‘jumps’, progressing to the next section only after the concrete in the previous one has achieved the necessary strength. For example, after a 2m section has been poured and set, the formwork is ‘jumped’ to pour the next 2m section. Typically, jumpform is used on buildings more than five storeys high, although if a fully-climbing system, it can be applied to 20-storeys and more. |
| What are the types of Jumpform system? | There are three main type of jumpform: Normal – involves formwork that is lifted off by crane and reattached at the next level above. Guided – similar to the normal method above but units remain anchored to the structure during the raising operation by crane. This method can be safer and more controlled. Self-climbing – this type of jumpform is raised on rails and so does not require a crane. |
| What are connections (in relation to steel) and what percentage would you expect them to be? | There are three most common types of connections in steel structures: welded connections, bolted connections, and riveted connections which serve to connect two or more steel components. They can also be used to join steel buildings to other types of construction, such as brick or concrete blocks. Despite accounting for less than 5-10% of the frame weight, connections influence between 40-60% of a frame’s total cost. |
| What is Post tensioned concrete? | Post tensioning is a technique for reinforcing concrete. Post-tensioning tendons, which are prestressing steel cables inside plastic ducts or sleeves, are positioned in the forms before the concrete is placed. Afterwards, once the concrete has gained strength but before the service loads are applied, the cables are pulled tight, or tensioned, and anchored against the outer edges of the concrete. Post-tensioning is a form of prestressing. |
| What is an A193 mesh? | A193 mesh is a lightweight welded prefabricated reinforcement mesh with 7mm wires. It is frequently used in domestic light duty applications as a fabric for reinforcing concrete slabs, walls and other constructions. Standard size of 2.4m by 1.2m Usually used in grade slab, concrete screed over Hollow core slabs etc. |
| How do you construct a glass partition? | Step 1: Measure and plan Step 2: Choose the type of glass partition Step 3: Install the glass partition tracks Step 4: Fit the glass panels Step 5: Install the frameless glass doors Step 6: Apply glazing gasket |
| What is External envelope? | The building envelope includes all the building components that separate the indoors from the outdoors. Building envelopes include the exterior walls, foundations, roof, windows and doors. |
| What are Building regulations? | The building regulations are a set of standards that are designed to ensure that new buildings, renovation work, alterations, extensions and conversions are carried out in a manner that results in safe, energy efficient and healthy homes. There are in-depth sets of regulations each relating to specific areas of construction, including structural performance, electrical and gas safety, drains, ventilation and fire safety. |
| What is the purpose of Soil Investigation report? | Soil investigation, often called geotechnical investigation, involves the study of soil and rock properties, groundwater levels, and other geotechnical parameters. It involves evaluating subsurface conditions to determine whether the soil can adequately support the proposed construction. A lack of proper soil analysis can lead to significant issues, including structural instability, excessive settlement, or even failure, resulting in increased costs and delays. |
| Why Soil investigation report is provided in a Traditional procurement route to Contractor? | For dewatering data, trial pit locations, types of soil/rock for deciding excavation method |
| What are typical components of Soil Investigation report? | 1. Introduction. 2. Objectives of the geotechnical investigations. 3. Details of the proposed structure. 4. Site conditions. 5. Field investigations. 6. Laboratory test results. 7. Soil profile. 8. Allowable bearing capacity. 9. Analysis and interpretation of the results. 10. Foundation alternatives. 11. Recommendations. 12. Limitations and uncertainties of soil exploration. 13. Annexure. |
| What are types of Soil investigation methods? | • Trial trenches & trial pits • Boreholes • Ground penetration radars |
| What is the need for soil improvement? | • To reduce the settlement of structures • Improve the shear strength of soil and thus increase the bearing capacity of shallow foundations • Increase the factor of safety against possible slope failure of embankments and earth dams • Reduce the shrinkage and swelling of soil |
| What are types of Soil improvement methods? | • Ground Reinforcement o Stone columns o Soil nails o Micropiles o Ground anchors • Ground Improvement o Surface compaction o Drainage o Dynamic compaction o Blasting • Ground Treatment o Soil cement o Lime admixtures o Flyash o Dewatering |
| What are types of types of Foundations? What are types of Piling? | • Shallow Foundations o Isolated/pad footing o Combined footing o Strapped footing o Strip footing o Raft foundation • Deep Foundations (Piles) o Based on load transfer End bearing piles Friction piles Combination of both o Based on method of installation Driven or displacement Bored or replacement o Based on material Timber Steel Concrete (Precast / cast-in situ) Stone and sand |
| What are the Advantages & Disadvantages of Raft Foundation? | • Advantages o Raft or mat foundation is economic due to combination of foundation and floor slab. o It requires little excavation. o It can cope with mixed or poor ground condition. o It reduces differential settlement. • Disadvantages o prone to edge erosion if they are not treated properly. o They are not effective if the load of the building is going to be focused on a single point |
| What is Underpinning? | Where the foundations of an existing building or structure require strengthening and stabilising, a process of underpinning may be necessary. Excavated soil from beneath existing foundations is replaced with material, usually concrete, in a series of phases that increase the overall depth. This forms a new foundation beneath the existing one. |
| Why underpinning maybe required to do? | • Subsidence (changes in the condition of the soil) or poor soil properties which may have caused the existing building’s foundations to move. This may be due to natural causes such as earthquake, flood, drought and so on. • Additional building storeys, either above or below ground level, are to be added, meaning that existing foundations need to be strengthened so as to adequately support the modified load. • Structures have been built nearby that alter the soil stability. • The original foundation is found to be inadequate in terms of its strength or stability. • The usage of the structure has been modified. |
| What is Shoring? | Shoring is the practice of building a temporary structure to support an unsafe structure on construction and excavation sites. Professionals use shoring to fix unstable walls, demolish structures, change existing walls, construct new walls and repair cracked or broken walls or foundations. When deciding which type of shoring to use, professionals take several variables into consideration, like the soil located on the site, the proximity of the site to other structures and the environment of their worksite, like if it’s wet, dry or near a body of water. |
| What are types of Shoring? | • H and I-beam shoring, also known as soldier pile walls, supports excavation endeavors that have a depth of 50 inches to 200 inches. Concrete panels are placed between the steel beams after they’re placed in the soil. • Sheet piling – corrugated steel sheets, used in marine construction • Contiguous piling – Piles with gap of 15 to 100 mm • Interlocking piles / secant piles – combination of primary non-load bearing and secondary load bearing piles • Diaphragm walls – typically used when all other shoring types are not strong enough to reach deep excavations |
| What are types of types of dewatering? | • Deepwell systems – A deep well system consists of an array of bored wells, each fitted with a multi-stage electric submersible borehole pump. As water is pumped from each well, the groundwater is lowered creating a cone of depression or drawdown around itself. • Ejector systems – Ejectors use air within the wells to produce a vacuum to draw water out of the soil. The system works by circulating high pressure water which is fed from a tank and supply pumps at ground level down the well into the ejector nozzle and venturi located at the foot of the well. The flow of water through the nozzle generates a vacuum in the well and draws in the groundwater. It is then piped back to ground level and back to the supply pump for recirculation. • Wellpoint systems – Wellpoint systems are used to lower groundwater levels to provide stable working conditions. They consist of a series of small diameter wells that are connected by a header pipe to a wellpoint pump. The pump creates a vacuum in the header pipe drawing water up from the ground. Wellpoints are typically installed along or around an excavation. The height to which water can be drawn by vacuum in this way is approximately 6 metres. To function at greater depths, well points can be installed in stages as the excavation proceeds. • Siphon draining – Siphon draining works by pumping water by gravity along primed siphon pipes. Wells are installed in or above the unstable zone of a slope and are pumped using siphons which exploit the natural sloping terrain. The wells reduce the pore pressure increasing the effective stress and stabilising the slope. Priming of the siphon is controlled by an automatic flushing system located at the downstream outlet of each siphon pipe. This enables the siphon to operate intermittently at low flows, maintaining the prime by preventing the build-up of air in the siphon. • Sump pumping – Sump pumping is the simplest form of dewatering and can be very reliable. Groundwater is allowed to flow into the excavation and is collected in sumps where it is then pumped away. In certain conditions, sump pumping can be very efficient and is highly cost effective, however uncontrolled seepage into the excavation can cause instability and other construction problems. Additionally, the disposal of the water needs to be handled carefully, to ensure that the quality of the water is suitable for discharge. |
| What is Early works package? | Early works in construction refer to the initial activities carried out on a project site before the main construction phase begins. They are tendered and commenced earlier than the main project works. E.g. Site Clearance or Site Preparation, Demolition, Utility relocations, Geotechnical investigations, Environmental assessments and remediation, Earthworks, Temporary access roads and fencing. |
| What is Enabling works? | Enabling works is a generic description for site preparation works that might take place prior to work under the main construction contract. This could include: Demolition, Site clearance, Tree protection, Diversion and/or disconnection of existing site services, Geotechnical and exploratory ground investigation, Decoupling from existing buildings, Decontamination, Ground improvement and/or compaction, Excavation of known below-ground obstructions, Survey work, Creation of access routes, Perimeter fencing and security provisions, Work to neighbouring buildings, Discharging planning conditions that must be satisfied prior to construction commencing, Historical architectural investigation fieldwork, Access ramps, Signage provisions, Provision of statutory utilities to the site. |
| What is Piling works? | Piling is the process of driving or boring pile foundations into the ground to form a deep foundation for buildings, bridges or other structures. These piles transfer loads from the structure to the ground, helping to support it. Piles are generally used when the bearing capacity of the surrounding soil is considered to be weak in structure due to the ground conditions or inadequate for the structural load of heavy construction. |
| What is cladding? | Cladding is a covering or layer applied to the external surfaces of a structure to protect it or give it a new look. Cladding can be made of a variety of materials, such as timber, plastic, brick, stone and glass. Cladding performs a number of important functions, including Protecting buildings, Changing a building’s aesthetic, Reducing maintenance, Insulating a building, Making a building more durable etc. |
| What are the types of cladding? | Brick cladding, Timber cladding, Stone cladding, GRC cladding, Metal profile cladding, Curtain walling, Sandwich panels, Patent glazing, etc. |
| What is BIM? | Building information modeling (BIM) is the holistic process of creating and managing information for a built asset. Based on an intelligent model and enabled by a cloud platform, BIM integrates structured, multi-disciplinary data to produce a digital representation of an asset across its lifecycle, from planning and design to construction and operations. |
| What is benefits of BIM in construction? | Constructability of a Design – It empowers you to see the end design visually, enabling you to decide the best way to construct a project. You can identify all potential clashes between components even before the construction phase. BIM also allows you to plan site logistics efficiently. Construction Sequencing and Scheduling – plan and simulate the construction phase virtually. This will help determine the most efficient construction sequence. Project Cost Estimates – making cost estimation easier, quicker, and more accurate. Completion and Handover Process – BIM allows you to maintain an accurate and real-time record of the construction phase. As the construction work progresses, you can update the information in the BIM model to make the information centralised and easily accessible to all the stakeholders. The BIM model can be used during the project’s complete life cycle for operations, maintenance, and refurbishment work. |
| What are the ways to eliminate Construction wastage? | A strong design – a good design can cut the amount of waste a project produces by using less material with standardised designs that reduce excess off-cuts. Efficient ordering – measuring everything to be exact and ordering accurately avoids ending up with excess materials. Regular inventory checks prevent buying extra. Buy direct – packaging waste makes up around 10% of construction waste. While packaging is essential to protect materials, going to suppliers direct to buy in bulk offers a solution to avoid individual packaging. Minimise mistakes – errors on construction sites cause waste by damaging materials so they can’t be used. Most of these will be accidents but to reduce the chance of mistakes it’s important to carry out a risk assessment and hire competent, skilled, and qualified workers (and supervisors, where relevant). Safe storage – protecting your materials from weather conditions and potential theft or vandalism reduces the chance of damage, which may result in unusable materials. This should be in a covered and locked container or location, where possible. Recycling bins – ensure bins and storage containers are placed conveniently around your construction site close to the point of waste production. This makes it easy for workers to separate waste and put it in the right container for recycling. |
| What is lean construction? | Lean construction is a project delivery process that focuses on creating value for the customer while identifying and eliminating waste throughout the entire design and construction process. This involves fostering a culture of continuous improvement and collaboration among all project participants to maximize efficiency, minimize waste, and deliver exceptional project outcomes. |
| What is Just in time? | Just-in-time (JIT) is a production and delivery system that ensures materials and components are delivered from the manufacturer to the production site at exactly the right moment to enable immediate use in the production process. A prime example is ready-mixed concrete: the perishable nature of this material means that having been mixed to the customer’s exact specification, it must be delivered at the right time, in the right quantity (and at the right specification) to allow pouring before setting takes place. Another example is windows or glazed cladding panels, where on-site storage would necessitate extensive inventory facilities and potential risks of product damage. JIT in construction has also been referred to as ‘lean construction’. |
| What is green concrete? | Green concrete, also known as eco concrete or eco-friendly concrete, is a type of concrete that utilises recycled materials and is specifically designed to minimise its environmental impact. It is created using waste materials like fly ash, slag, and recycled aggregate, reducing the consumption of natural resources and energy required in the production process. |
| When would you recommend to use a PT slab? | For structures where longer spans are desired, like parking structures. Post-tension slabs might also be used for construction in areas with building height restrictions. Because post-tension slabs are thinner, the building will be shorter. |
| What are the disadvantages of PT slab? | It requires highly specialized labour and machinery. The design calculations for post-tensioned concrete elements are more complex and expensive than the traditional ones used to design reinforced concrete elements. Post-tensioned concrete structural elements are susceptible to corrosion. The cost of the post-tensioned concrete construction system is higher, due to the fact that the anchors are unrecoverable and that the reinforcement bars need to be inserted correctly inside the conduits. Extreme attention is required during the installation of the reinforcement anchors and their coating. Unable to modify the slab/do core cutting. |
| What is Façade? What are the types of Façade? | The term ‘façade’ is used to refer specifically to external faces of buildings or vertical face of a building envelope. Facades serve both aesthetic and functional purposes. These systems play a crucial role in creating the overall appearance of a building and protecting it from external elements, such as wind and rain, alongside insulating your building. Types of Facade are: 1. Lightweight facade such as Curtain wall, Panel facades made of aluminium 2. Heavyweight Façades are typically made of solid materials, such as concrete or stone 3. Traditional Façades found in older buildings or residential homes, are constructed using traditional building materials such as brick or stone |
| What are the Type of façade curtain wall system ? | Stick Curtain Wall System: In this type of curtain wall system, the components are assembled piece by piece on the structure of the building. This system is mainly used for low-rise buildings. This comprises a proprietary system of aluminium box-section mullions and transoms assembled on site, into which glazing and panels can be installed. This system promises flexibility as it gives space for onsite adjustments. Unitized Curtain Wall System: In this type of curtain wall system, the parts are already assembled in the factory. The components are installed and brought as a single unit from the factory to the site. Popular in high-rise buildings. This system offers the benefits of quick construction and good quality as the components are manufactured in a factory setting. |
| What is curtain wall? What are its components? | A curtain wall is a thin, aluminum-framed wall. It can come with different fillings which include glass, metal panels, or thin stones. The framing is joined to the building structure. It doesn’t bear the load of the roof or the floor; instead, it relies on the building structure, specifically at the floor line. Following are the structural elements of a single curtain wall unit installed on the building structure. Transom Mullions Vision Glass Anchor |
| What is BMU? What are its types? | Building Maintenance Unit is a type of permanent mechanical access equipment generally installed on the roof of the building that is operated manually, automatically or by remote control. It provides permanent mechanical access for the maintenance of a building’s facade. It is often referred to as a window cleaning cradle, a gondola or a gantry. Types of BMU are: Fixed base, luffing jib, parapet trolley, telescopic jib, tracked, trackless, trolley and power winch cradle. |
| What is waterproofing? What are the types of waterproofing? | Waterproofing is the process of making a structure waterproof or water-resistant so that it remains relatively unaffected by water or resists the ingress of water. Types of waterproofing are: 1. Cementitious Waterproofing Method – easiest method, material readily available, often used in the internal wet areas such as toilets, other places used are Sewage Treatment Plants, bridges, dams, tunnels etc. 2. Liquid Waterproofing Membrane Method – Liquid membrane is a thin coating which consists of usually a primer coat and two coats of top coats which are applied by spray, roller, or trowel. It offers more flexibility than the cementitious types of waterproofing. The liquid cures into a rubbery coating on the wall. Locations used are roofing, balconies and decks, kitchens or wetrooms, bathrooms, and showers. 3. Bituminous Coating Waterproofing Method – Bitumen, also known as asphalt, is a sticky, black and highly viscous liquid or semi-solid form of petroleum. Thanks to its waterproofing qualities, it is widely used in construction. Bituminous membranes are perfect for waterproofing roofs, basements, below-ground structures, bridges and other structures. 4. Bituminous Membrane Waterproofing Method – is a popular method used for low-sloped roofs due to their proven performance. Bituminous waterproofing membrane have torch on membrane and self-adhesive membrane. 5. Polyurethane Liquid Membrane Waterproofing Method – used for the flat roof area and exposed to weathering. This waterproofing method is expensive. Used in roofs, balconies, wet areas, water tanks, etc. |
| What is a combo roof system? | Combo Roof System is an all-in-one roofing solution that combines waterproofing and thermal insulation (and even finishing) for the entire flat roof. Its components are: Polyurethane foam, rubberized coating, geotextile separation layer, screed concrete, pu sealant and backing rod for expansion of concrete, top coat made of cementitious/acrylic/polyurethane coating. |
| What is a DPC? | A damp proof course (DPC) is a physical barrier that prevents water from moving up a wall. This process of water travelling up through walls is known as rising damp. You can either use liquid DPCs or physical DPCs to prevent this from happening. |
| What is HVAC? | HVAC stands for Heating, Ventilation, and Air Conditioning. A residential HVAC system is a complete home comfort system that can heat and cool your home, as well as provide improved indoor air quality and humidity control. |
| What are the types of HVAC? | The major classification of HVAC systems is central system and decentralized or local system. 1. Chillers – there are two types: a. Traditional Condenser Water System – The condenser water circulates in a loop to the cooling towers. The cooling tower fans then push air across the condenser water to remove absorbed heat. Condenser water systems require extensive infrastructure – chillers, pumps, pipes, air handlers, cooling towers, and water treatment systems – but can achieve efficiencies of scale. typically seen in larger office buildings. b. Air-Cooled Chiller System – using fans to blow outdoor air across refrigerant coils outside the building to dissipate heat.Though less efficient in extreme weather or for very large buildings, air-cooled chiller systems have lower operating costs for small to mid-sized offices. 2. District Cooling – District cooling relies on a centralized cooling plant that provides cooling to buildings within its grid. The plant supplies chilled water through a network of underground insulated pipes. Building owners pay the district utility company based on how much chilled water they use. 3. VRV or VRF – Variable refrigerant flow (VRF) systems, also called variable refrigerant volume (VRV) system regulates refrigerant flow to match the heating and cooling demands of different zones, allowing for individualized temperature control and energy efficiency. In short, it enables end users to independently manage multiple air conditioning zones simultaneously. VRF systems provide flexibility, potential energy savings, and lower maintenance costs than central plant equipment. |
| What is the RIBA plan of work? | The RIBA Plan of Work is published by the Royal Institute of British Architects (RIBA). Split into a number of key project stages, the RIBA Plan of Work provides a shared framework for design and construction that offers both a process map and a management tool. The RIBA Plan of Work organises the process of briefing, designing, delivering, maintaining, operating and using a building into eight stages. 0 Strategic Definition – The best means of achieving the Client Requirements confirmed 1 Preparation and Briefing – Project Brief approved by the client and confirmed that it can be accommodated on the site 2 Concept Design – Architectural Concept approved by the client and aligned to the Project Brief 3 Spatial Coordination – Architectural and engineering information Spatially Coordinated 4 Technical Design – All design information required to manufacture and construct the project completed 5 Manufacturing and Construction – Manufacturing, construction and Commissioning completed 6 Handover – Building handed over, Aftercare initiated and Building Contract concluded 7 Use – Building used, operated and maintained efficiently |
| What is the National Building Code of India? | The National Building Code of India (NBC) SP 7 : 2016, a comprehensive building Code, is a national instrument providing guidelines for regulating the building construction activities across the country. It is made up of 2 volumes. Volume 1 comprises various parts such as: DEVELOPMENT CONTROL RULES AND GENERAL BUILDING REQUIREMENTS, FIRE AND LIFE SAFETY, BUILDING MATERIALS, STRUCTURAL DESIGN Volume 2 comprises: CONSTRUCTION MANAGEMENT, PRACTICES AND SAFETY, BUILDING SERVICES, PLUMBING SERVICES, LANDSCAPE DEVELOPMENT, SIGNS AND OUTDOOR DISPLAY STRUCTURES, APPROACH TO SUSTAINABILITY, ASSET AND FACILITY MANAGEMENT |
| What are the green building regulations in UAE? | Dubai introduced the green building regulations containing 79 specifications, which is now mandatory for all developments. Green Building Regulations and Specifcations in the Emirate of Dubai are regulations to improve the performance of buildings in Dubai by reducing the consumption of energy, water and materials, improving public health, safety and general welfare and by enhancing the planning, design, construction and operation of buildings to create an excellent city that provides the essence of success and comfort of living |
| Under what circumstances you will propose steel structures? | 1. Industries require greater clear span of about 25 to 30m along the width, without any intermediate column. 2. Faster construction is preferred 3. easy to modify the structure |
| How will you prevent corrosion of the Steel structures? | Protective barrier coatings are the most effective way to prevent corrosion on structural steel. Applying protective coatings significantly extends the life of a steel structure. |
| What are various BIM dimensions and what is it used for? | In concept, a BIM dimension refers to the different uses for a BIM process. Each dimension adds a layer of thought to the process for a particular use. These dimensions enrich the BIM data set and make it more useful to various stakeholders throughout an asset’s lifecycle. 3D is the most common use of BIM, and it represents the basic structure of a project. drawings consist of an X, Y and Z-axis 4D BIM adds the dimension of time to the 3D BIM model. It overlays scheduling information into the model, allowing users to visualize the construction sequence and plan aspects of the project more effectively. 5D BIM incorporates estimating and cost data into the model. It is a powerful tool for budget management and cost analysis. Other BIM Dimensions – Sustainability, Facility management, Safety |
| What methods you will advice if you have to strengthen a building below the ground? | Underpinning. |
| What are the types of underpinning? | 1. Mass concrete underpinning – is the most common method of underpinning. The ground below the existing building foundation is excavated in controlled stages (or pins). When strata suitable for bearing the weight of the building has been reached, the excavation is filled with concrete and left to cure before the next pin is excavated. 2. Pile Underpinning – In this technique, piles are inserted into either side of a wall to support the weakened foundation. Each pin or needle is driven through a wall and attached to the inserted piles. Each needle works like a pile cap. Pile underpinning is recommended for treating soil settlement resulting from clayey nature or water clogging. 3. Mini-piled underpinning – This is most suited to sites with variable ground conditions, restrictive access, or environmental pollution. It is used when foundation loads need to be transferred to stable soils at considerable depths. 4. Expanding resin injection – This is a more recent development which is cleaner and less disruptive. It involves the injection into the ground of a structural resin and hardener mix, or strengthening grout, that chemically reacts to expand and compact weak soil, thereby raising and re-leveling a structure. |
| What impact will AI have on the construction industry? | A large overhead for the majority of Main Contractors is the estimating process which can be very onerous and require weeks of input from skilled estimators. AI can assist the estimating process by supporting estimators with data collection and processing when reviewing large tender packs made up of contract documents, drawings, specifications and legal documents. Site safety AI powered cameras can scan construction sites to detect potential safety hazards for example if a worker forgets to wear their helmet an alert can be generated to advise the site management to intervene. AI driven sensors can be placed on site plant and machinery to predict when maintenance inspections and replacements should be undertaken. Plant and machinery down time can cause significant cost and delays which AI can play a part in reducing. AI technology can use energy modelling software to adjust lighting, HVAC and security systems to reduce operating costs and improve energy efficiency. Automation of construction tasks is also being carried out for repetitive and labour intensive tasks such as bricklaying, excavation, and welding. |
| What are the technical advantages of steel frames? | Steel frames are often quicker to assemble in comparison to alternative methods. They are 100% recyclable and inorganic meaning they will not warp, split, crack or creep. Steel frames also offer the highest strength to weight ratio of any building material availble and are not vulnerable to termites or any type of fungi or organism. They are dimensionally stable and do not expand or contract with moisture or temperature changes. Due to strict manufacturing controls, consistent material quality can be obtained due to production taking place in line with strict standards. Steel is non-combustible so it will not contribute to the spread of a fire and is also lighter in comparison to concrete frames and will often benefit from a cheaper foundation solution. |
| What are the disadvantages of steel frames? | Steel frames require fire protection to be retrospectively installed in the form of boarding or protective coatings such as intumescent paint. Fixing components may require replacement over time and the price of steel often fluctuates which can result in a lack of cost certainty. Installation of steel frames requires experienced and skilled builders which carries a cost premium in comparison to other building methods. Skilled labour resources can also be difficult to acquire depending on market conditions. Due to the speed of installation, steel frames can carry a high cashflow burden on the employer or developer early on in the construction cycle in comparison to other forms of construction. |
| What are the technical advantages of concrete frames? | Fire protection is often provided inherently as part of the structure. Due to offering a slower form of construction in comparison to alternative methods, this will likely result in reduced cash flow expenditure early on in the development. Maintenance requirements associated with concrete frames are relatively low in comparison to alternative methods. Concrete frames often provide good sound and heat insulation properties in comparison to steel frame construction. |
| What are the technical disadvantages of concrete frames? | In comparison to steel frames, concrete is often more time consuming to install. There may also be complications during the install resulting from cold or inclement weather conditions. Concrete frames are often heavier and require larger foundation solutions which are usually more expensive. |
| What are the different types of piled foundations? | Sheet piles take the form of a deep trench which is excavated and concrete then poured in situ, the piles can be used to form basement walls or act as retaining walls. Secant piles have interlocking male and female piles with different diameters and hardness. These are bored to provide a combination of foundations and basement walls. They support in providing a waterproof structure and are often seen when a top down construction method is used. Bored Piles are formed with an auger to excavate the soil and concrete is then poured in when the excavation is complete. Pre-cast piles are hammered into the ground however this is not often favoured due to the high noise levels associated with installation and the lack of flexibility in terms of the foundation depth required. |
| What are the different ways that piled foundations transfer their load to the surrounding ground? | End bearing piles transfer the building load through low bearing capacity soil to a strong stratum such as rock or very dense sand. Friction piles bear on frictional resistance between their outer surface and the soil they are in contact with. Settlement reducing piles are usually incorporated beneath the central part of a raft foundation in order to reduce differential settlement to an acceptable level. Tension piles resist uplifting forces that might otherwise cause the structure to be extracted from the ground due to uplifting forces such as hydrostatic pressure, seismic activity or overturning movement. |
| What is the difference between bored vs. pre-cast piles? | Bored piles are formed with an auger that uses a boring technique to remove the spoil to form the hole that concrete and reinforcement is then placed into. They are used primarily in cohesive subsoils for the formation of friction piles and when forming pile foundations close to existing buildings where the allowable amount of noise and vibration is limited. Pre-cast piles are generally used where soft soil deposits overlie firmer strata. These piles are usually driven using a drop or single action hammer. Issues can arise due to the noise levels associated with the installation method of pre-cast piles. |
| What are the 3 main methods of waterproofing a basement? | 1. Structurally Integral Protection – Dense monolithic basements are designed and built to form a watertight space using high quality reinforced concrete. This requires good workmanship and strict quality control with their success depending on the water to cement ratio and the degree of compaction. Joints also need to be carefully designed and sealed. 2. Tanking basements use materials such as asphalt, polythene sheeting, bitumen and epoxy resins. These can be applied internally or externally to provide a continuous membrane to the base slabs and walls. External application is better as it protects the structure in addition to the waterproofing. 3. Drained Cavity solutions can be used for new or refurbishment work. This allows a small amount of water infiltration to occur. The water is collected and then drains away to a sump or is directly discharged using a pump. |
