29 September 2021
Large-scale High-rise Projects Need Large BIM-experienced Teams
High-rise construction began in the late 1800s in the United States, and it scaled great heights on its journey into the 2000s. The scale of high-rise construction expanded horizontally as well, where large high-rise projects involved several multi-storey buildings in the same location. Thus, the larger the project, the more complex its needs became. The benefits that BIM (Building Information Modelling) technology provided to tackle increasingly complex needs became invaluable, and architectural BIM modelling, Revit 3D BIM modelling and other BIM services have quickly become indispensable in high-rise building construction.
Different sources have different definitions for high-rise buildings. Some of them are:
- A multi-storey building between 35-100 metres tall
- A building with 12-39 floors
- A structure for which its height can seriously impact evacuation
- A building is taller than 70 feet (21 metres)
- A building that is taller than the maximum height people are willing to walk up
It’s plain to see that high-rise buildings require mechanical vertical transportation, which means that the use of high-rises are limited. Typically, these include residential apartments, hotels, office buildings, retail, healthcare and educational facilities. The modern era has seen greater use of mixed-use buildings, which host residential, office, hotel and commercial space simultaneously.
Regardless of its height or number of storeys, high-rise buildings are large and have high unit costs. Commercial and office spaces in high-rises require high levels of flexibility. High-rise buildings have certain key considerations and needs that require careful attention. They are as follows:
- Primarily a vertical cantilever beam with its base fixed in the ground, a high-rise building’s structure must carry vertical gravity loads and lateral wind and earthquake loads.
- Adequate shear and bending resistance are required.
- Its vertical load-carrying capability must be permanent, even under windy circumstances. (During strong winds, the columns on the windy side stretch away from each other, and columns on the other sides squeeze together.)
- Wind pressure causes the high-rise to bend, with the top experiencing maximum deflection. Wind passing the building creates vortices near the corners, which are unstable. Pressure changes as vortices break may cause a sway, or periodic motion, to the building. Thus, high-rises must satisfy several performance criteria.
- Stability is of prime importance – the building must not topple over.
- Deflection, or sidesway at the top, must stay within a maximum value (usually 1/500 of the height) to avoid damage to partitions and other elements.
- Occupants must not perceive any swaying motion caused by vortex shedding.
- High-rise foundations support considerably heavy loads.
- Concrete caisson columns bearing on rock are used, or the foundation is built on exposed rock. Bearing piles and floating foundations are also used.
- Energy released during earthquakes propels waves through the earth’s crust, which is transferred to buildings.
- Timber frame buildings are light and flexible, experiencing minimum earthquake damage.
- Masonry buildings are heavy and brittle, and thus can experience severe damage.
- Continuous frames of steel or reinforced concrete experience a medium degree of damage, depending on their design.
- High-rise structures must meet both lateral load performance criteria, and they must use materially efficiently and within budgets.
- Lateral resistance is provided by rigid joints; this system rises 90 metres (300 feet).
- A rigid frame with a vertical shear truss in steel or a shear wall in concrete can be 38 to 150 metres (125 to 500 feet).
- The framed tube structure in both steel and concrete provides greater gravity load, increasing lateral rigidity and can be 38 to 300 metres (125 to 1,000 feet) in height.
- The trussed tube with interior columns, in either steel or concrete, provides diagonal bracing on all building sides, carrying gravity loads and increasing lateral rigidity.
- The bundled tube, with framed tubes joined together for greater lateral rigidity, is used for structure that are 75 metres (250 feet) tall.
- High-rise building enclosure systems are typically curtain walls.
- High wind pressures and vortex shedding effects need thick glazing.
- Large areas of enclosed surfaces means that thermal movements, wind and seismic-induced movements must be carefully considered.
- Curtain walls must have fixed vertical tracks or other attachments for window-washing platforms.
- Stairways serve as vertical emergency exits in high-rises; during fire, elevators are automatically shut down.
- Emergency generator systems permit the rescue of people trapped in elevators by a power failure.
- Generators also serve emergency lighting and fire pumps.
- Fire-suppression systems often include sprinklers.
- There may be a separate piping system to maintain water pressure and bring water to fire-hose cabinets in the building.
- Exterior connections at street level must be included for portable fire-truck pumps.
Vertical Transport Systems
- Escalators move high volumes of people vertically over short distances.
- High-rises also use the roped elevator, which runs on a direct current electric motor that raises and lowers the elevator in a shaft with wire ropes placed over a series of sheaves at the motor and the elevator.
- Some high-rises use the sky lobby system to save elevator-shaft space. The building is divided vertically into sections, each with its own lobby floor. Large express elevators from the ground floor go to the upper lobby floors, where they transfer to elevator banks that go to individual floors within the sections.
- For high-rise plumbing, domestic water-supply systems need electric pumps and tanks to maintain pressure.
- Water systems may be divided into zones, each with its own pump and tank.
- Air-handling equipment can be laid out with centralised fans at every 20 floors, so air moves vertically through trunk ducts through each floor
- They can also use fan rooms on each floor to provide air.
- High-rises use limited centralised cooling systems.
Utility companies may bring high-voltage lines inside high-rise buildings to a series of step-down transformers in mechanical equipment spaces.
These are only a few of the many considerations that large high-rise projects require. There are extensive details and data that must be collected, collated, calculated and communicated accurately. Numerous benefits ensue from using BIM technology to help create near-flawless design for high-rise buildings and their many aspects.
Benefits of BIM
- Capture Reality
- Data is collected, compiled and shared in a 3D model to accurately represent reality and streamline project processes.
- Rework and duplication of drawings for the many different requirements of building disciplines is reduced with a shared model.
- The BIM model contains extensive data, allowing annotation and intelligent project connection.
- BIM drawing tools are fast, and each object is connected to a database.
- A vast database helps calculate the number and size of windows and all other elements for quantity takeoffs, which are updated automatically when changes occur.
- In a high-rise building, there will be greater data to contend with, and BIM practices will ease complications and reduce errors.
The BIM workflow involves Autosave aids and connections to project history in BIM-enabled software helps prevent sudden disappearances or corruption of files.
- Sharing and collaborating with models is easy.
- Project management is increasingly delivered in the cloud, such as Autodesk’s BIM 360 Design solutions.
- Tools for different disciplines enable the sharing of complex project models and integrate data with project stakeholders.
- Review and markup steps ensure that all stakeholders are aware of design evolution.
Simulate and Visualise
- Simulation tools in BIM-enabled software allow the visualisation of such details as sunlight in any part of a building at any time of the year or reflect the calculation of building energy performance.
- The software can analyse and model design concepts to attain optimum performance, incorporating data that can be used quickly and accurately.
- BIM tools help detect and resolve clashes of elements, such as an electrical cable or a duct that intersects a beam.
- Creating models first helps identify clashes early in the process, reducing costly on-site errors.
- Using the model helps prefabricated elements fit perfectly together and later be installed with minimum errors.
- Using a BIM model, steps, materials and crews can be sequenced easily for a more efficient process.
- Including the use of animation, the model facilitates the coordination of steps and processes.
Work with Detail
- In addition to knowledge transfer, BIM modelling helps share plans, sections, elevations and reports.
- Automation and customisation features help save valuable drafting time.
Using 3D modelling results in fewer steps to render impressive views and walk-throughs for selling commercial space or gain approvals.
As a model connected to a database with cloud capability, the model and its details can be accessed from anywhere, on any device.
Collaborate and communicate
Storing all project documents in a single view enables teams using BIM to collaborate and communicate more effectively.
In the age of BIM virtual construction, the advantages of using BIM services, such as architectural BIM modelling and Revit 3D BIM modelling, are too far-reaching and numerous to ignore. The only challenge that remains is to find the most suitable BIM modelling services partner with the requisite Revit BIM knowhow to help deliver projects on time, of high quality and within budget.
XS CAD has valuable experience providing BIM modelling services and BIM virtual construction services for general contractors and design consultants. Our range of services for building design firms across the world include architectural BIM modelling and Revit 3D BIM modelling services. We create these models and drawings by using Revit, AutoCAD and BIM 360 Design for cloud collaboration.