The principal drivers to build tall vary considerably from city to city around the world but are intrinsically linked to two key drivers; wealth / power and / or limitation on space. History shows that there has always been a passion, if not obsession, to stretch boundaries of engineering and construction by building high; essentially where no man has ever been before.

Megatall

Within the next decade we are likely to see not only the world’s first kilometer tall building, The Kingdom Tower, Jeddah, but a significant number of tall buildings that could stretch over 600 meters high (2000 ft). These are known as the “megatall” buildings.

Within the next decade we are likely to see not only the world’s first kilometer tall building, The Kingdom Tower, Jeddah, but a significant number of tall buildings that could stretch over 600 meters high (2000 ft). These are known as the “megatall” buildings.

To put that in perspective, that is four times the size of the Shard in London. A few years ago, this type of building was not even in existence and yet the Council on Tall Buildings and Urban Habitat (CTBUH) pipeline shows that we can anticipate over ten “megatall” buildings to exist across the world by 2020. Interestingly all of these buildings exist in either the Middle East or Asia. The tallest building under construction outside of these regions is the One World Trade Centre, in New York, which will stand at 540 meters.

The shift from West to East

Currently nine out of ten of the world’s tallest buildings are located in Asia, led by the Burj Khalifa in Dubai, UAE. During 2012, a staggering 66 new tall buildings (200m or more) were built across the World. Interestingly, three out of the top four tall buildings are planned to be built in Dubai, UAE.

In the late 1980’s, the top ten tallest buildings in the world were all located in North America; nine in the USA and one in Canada. Over the past 25 years the geographical make up of this list has shifted eastwards, corresponding to the economic emergence of these nations. As Asian economies grew and looked to establish themselves as global economic markets, so too did the height of their buildings. It is evident that countries use architecture to demonstrate the development and achievement of their nations.

1998 marked a definitive shift from West to East for tall buildings, when the Petronas Towers in Kuala Lumpur, Malaysia, officially became the world’s tallest buildings. The towers were the first outside of the US to hold this honour. This followed a succession of tall structures in the east, including the Taipei 101 in 2004 and the Burj Khalifa, launched in 2010.

Why the shift?

There are four main reasons for this shift from West to East. The motives help us to understand what is driving the change in landscape for tall buildings.

1. Planning governance

In mature markets (specifically the West), planning governance has had a significant impact in controlling the height of buildings. Many mature cities want to protect the view of their skyline. In contrast, the Middle East has a much more relaxed planning regime, which is enabling this shift. For example, in 2004 Dubai Marina’s first phase was complete and by the end of 2013 the surrounding area will comprise of numerous high rise buildings. This shows a rapid turnaround, whereby planning governance is not withholding any of these developments. This area in Dubai is often referred to as the “tallest block in the world” because 14 out of 20 of the current tallest buildings in Dubai are located in the Dubai Marina district.

Megatall

During 2012, a staggering 66 new tall buildings (200m or more) were built across the World. Interestingly, three out of the top four tall buildings are planned to be built in Dubai, UAE. (Click on graphic for a larger view.)

2. Land value + the economy

As outlined in the graphic on page three, there is a direct link with economic growth (GDP) and where tall buildings are constructed. The emerging markets, typically in the Middle East and Asia, land values are low and the economy outlook has been promising. In contrast the Western market land values are particularly high with little GDP growth.

3. Population increase

In heavily populated cities land is scarce and valued greatly. As a consequence, these cities that have a high population rate have more demand for tall buildings. The population rate across Asia is huge and the land is scarce, therefore the need to build tall is a necessity in the East.

4. The demand for recognition and prestige

New emerging markets continue to command recognition and as a result society demands new developments and infrastructure. As countries in the East build more iconic and tall buildings, prestige and recognition follows. These tall constructions often anchor other developments and infrastructure and encourage new value to be created in the surrounding areas.

For example, the world’s current tallest building The Burj Khalifa, represents a significantly high valued piece of real estate. As a result this was made the centerpiece of a new business and residential district in Dubai and consequently a premium is charged for properties in the area, specifically for those with clear views of the skyscraper. Even if the Burj Khalifa failed to return a profit, its presence will raise the surrounding property value enough to more than offset the difference.

What Does it Take to Develop a “Megatall” Structure Safely, Efficiently and at Speed?

A megatall building is unlike any other building, it is truly unique. Many key factors need to be taken into consideration as early as possible to ensure a safe and efficient structure is adhered to, within time and to budget.

In this paper we identify seven areas that need consideration when constructing a megatall building.

The risks associated with building tall are ever more amplified when compared to any other building. Therefore, it is of critical importance that a developer and/or an investor is fully aware of the key drivers associated with the construction of a “megatall” building, irrespective of use or ownership.

The key drivers include:

1. Health and safety first

Building tall represents many risks and as a result, health and safety should always be foremost in any construction project. A “megatall” structure has to consider the risks as does any other construction project, but there should also be a focus on key areas, such as:

Site inductions

Site inductions for all site personnel are a feature of all building projects however these must be tailored to the risks of working at height. They must constantly be updated as the building increases in height. In addition, access to upper areas must be controlled and restricted to those that need to work in these areas.

Site welfare

As a building rises, welfare facilities need to follow. Workers must have access to toilet facilities, a canteen and rest areas close to their areas of work. In addition, considerable planning of the movement of workers at the start and finish of shifts is required, in accordance with available temporary vertical access facilities.

Prefabrication

Where possible, elements which pose the greatest risk of installation at height, should be prefabricated, particularly those on the periphery. Complex items should be trial assembled at ground level first and particular care is required with loose fittings which should be contained and tools which should be tethered.

Fire

Construction site fires are always a major risk particularly as a building nears completion. The fire risk for a “megatall” structure is multiplied. In addition to usual good practice and policing, consideration should be given to early completion of refuge and escape stair areas.

Megatall

Typically, as the height of a building increases so does the cost of construction, the challenge is to hone this as early in the feasibility process as possible. In addition, there is a potential uplift in sales price from those units on the upper floors, particularly iconic tall buildings.

2. The economy and market

Evidence shows that there is a direct link between economic growth and building tall (see graphic on page three). Market conditions clearly have an effect on the viability of a tall development.

Securing finance for “megatall” projects is an important element (if not the most important) to ensure successful delivery. There are many large and varying investments made once the preparation and detailed feasibility studies have been confirmed, to ensure the target is reached by the investors and much of this is linked to the market and economic demand.

Tall buildings often take longer to achieve statutory approvals because each country has specific building control guidelines. For example, the Landmark Tower in Abu Dhabi was one of the first high rise developments in the city, where potential conflicts between international guidelines and interpretation of local building codes and fire evacuation guidelines had to be managed carefully to meet municipality satisfaction. Due to the very complex nature of a high rise design and construction process it is necessary that robust planning is undertaken to crystalise development expectations. Usually tall buildings are fuelled by pre-let tenant arrangements or pre-sales to consolidate the business case through off setting potential commercial risk.

Market and tenant need

Wherever you are in the world, no-one is currently building a tall tower without any tenants or potential occupants. A development will always be aligned to the market need and should focus on a specific segment demand. This will initially be led by market research to determine demand, which shapes the developers product. The common thread across highly successful tall buildings is ‘quality’, but it is important to note that not all tall buildings need to be iconic or ‘cutting edge’. Nonetheless, they do have to be very well conceived, designed, managed and constructed, to align to market and tenant requirements.

3. The structure vs. value

Price vs. height and shape

The viability of any development is dependent on costs vs revenue. These factors get ever more complex when building tall. Typically, as the height of a building increases so does the cost of construction, the challenge is to hone this as early in the feasibility process as possible. In addition, there is a potential uplift in sales price from those units on the upper floors, particularly iconic tall buildings.

Size and regularity of floor plate

Our bespoke modelling and benchmarking capability for tall buildings, can measure and estimate typical cost per square foot of constructing a tall tower, in line with market need. The floor plate efficiency is critical to the viability of any high rise tower and floor to wall ratios are of fundamental importance to this. Due to our in depth knowledge and understanding of the key cost drivers for tall buildings we are able to advise from the outset of concept design of any potential risks or opportunities.

Structure solutions

A clear definition of structural principles, such as structural material and core locations must be understood from the outset. The integration of these principles with the architectural and MEP Services design is vital to create an effective design solution. In our experience often key design decisions are formulated in the concept stage for a high-rise design. These decisions can heavily influence all resources committed thereafter to both design and construct the development. Therefore it is imperative that a fully integrated team is in place from conceptual design to ensure that all decisions are fully considered and developed as early as is practically feasible and have minimal impact on the developments viability.

Facade specification

The façade specification is critical to the success of any tall building not only from an aesthetic perspective but also in terms of budget and viability. The selection of the system can increase the construction budget by up to 10% and the total costs of the façade can amount to 20% of the total shell and core cost of the tower. It is important to note that whilst the façade specification is often driven from the aesthetic aspirations, careful consideration of the thermal, acoustic and structural performance is required to ensure that the correct system is finally selected.

Vertical transportation strategy

The movement of people is particularly relevant in the success of any high rise development. The type of vertical transportation system is often linked to the specific use of the building and indeed in many cases the mixed use of the building will facilitate the requirement for sky lobbies in high rise towers. Double decker lifts, a relatively new technology, has been used in some of our high rise developments to provide our clients with an efficient solution to minimise tower core area requirements and to meet the commercial office tower passenger requirements.

Megatall

Where possible, elements which pose the greatest risk of installation at height, should be prefabricated. Broad Sustainable Buildings plans to assemble 95% of its Chinese ‘Sky City’ in a factory.

4. The location and site approvals

Site constraints

A thorough understanding of the localised constraints is essential, such as;

  • Ground conditions
  • Abnormal conditions
  • Planning legislation
  • Legal issues, such as rights to light, air rights etc
  • Physical interfaces
  • Stakeholder management

All of these issues are absolutely critical to project success. Early establishment of the constraints and opportunities will frame the success of the development and mitigate the risk of derailment.

Planning approval

Planning and code approvals (including seismic requirements) become ever more complex at height, as do engineering and constructability issues.

It is often the case that the development of a significant landmark high rise development will increase the value of the associated nearby land, and at times the tower could prove to be a loss leader in an overall development. Burj Khalifa, as referenced previously, probably falls into this category. It is important to highlight specific opportunities to investors on this when securing finance and coming up against planning and site constraints.

5. Quality underpins value

Product quality is of paramount importance for any development, but most significantly for a “megatall” construction, because quality ensures the development value is optimised.

One common thread that links tall buildings in every country, across the world, is that ‘quality underpins value’. In this respect, the most successful tall buildings share high design and construction quality and space vs. cost efficient metrics. Prime occupiers demand quality that resonates with their own corporate brands.

Buildings designed and constructed to class leading standards are rarely compromised by poor yield and rental voids. Conversely poorly conceived, designed and constructed tall buildings make up the majority of under utilised real estate in cities around the world. Furthermore, iconic buildings command recognition as place makers, which often anchor major developments through game changing value creation. The outcome is therefore of both macro and micro economic impact and significance.

6. Embrace and enable new technologies and innovations

Many of the challenges faced in the development, design and construction of tall buildings, focus on finding innovative responses to mitigate risks associated with the key cost drivers. This could be in the structural design, sustainability, efficiency of floor plates, or the cost and value implications of alternative methodologies. We continually have to conduct extensive research for our clients, meet with the top professionals within the relevant industry bodies, review up to date best practice external publications and of course communicate effectively with our fellow professionals. This allows us to better inform our clients of what new innovations and technologies are required to overcome the perceived restrictions.

For example a client looking to develop a “supertall” tower in Abu Dhabi, wanted advice on the pros and cons of building a tower at potentially 400m, 500m or 600m tall. Within a few weeks, together with the internationally renowned design team, following intensive review and analysis, we advised the client on which scheme would work most efficiently, effectively and on time, from either an aesthetic, financial or indeed functional use perspective. In addition to this, we were able to advise the client of the “should cost” of the Tower.

7. Optimise a high performing team

A team with extensive experience of tall buildings that has learnt from the iterative process of setting higher standards on each project and the challenging boundaries will provide a robust platform and will ensure that quality and value is maximised and delivery risk is kept to
a minimum.

Collaboration across the supply chain is vital and it is ever more important that the team is integrated and proactive to deliver. A strong leadership should ensure that across all areas of design and construction the supply chain is delivering a high performing team.

What Should the Focus be on When Building Tall?

A focus on viability, efficiency and the speed to deliver is vital to building a successful megatall construction. Within this, technology and innovation, as well as collaboration and leadership play a key role across the supply chain, to ensure the delivery of a successful “megatall” building.

Watch a video below of Keith Brooks, Global Head of Property and Social Infrastructure, discussing why build tall:

Keith Brooks

Keith Brooks is Global Gead of Property for EC Harris, a leading global built asset consultancy.