Steel-framed modular construction for high rise buildings is a constant practice in places like Europe and has been for many years. However, North America is only just coming to terms with this type of construction for high rise buildings. Although wood-framed modular construction for low rise buildings is common in this part of the world, the process of using steel-framed modules for high rise buildings are still a rarity.
There are lots of benefits that come with the steel-framed construction for high rise hotels. This article focuses on everything you need to know about this construction approach. However, before we dive right in, it is important that we know what modular construction means.
Modular construction involves the prefabrication of buildings (or major parts) off-site under controlled factor conditions. Each piece of the prefabricated building is referred to as a module. And a module can include the complete structure of a conventional building. That is; exterior and interior finishes, electrical, furniture, plumbing, fixtures, & equipment, and mechanical.
To convert modules into complete buildings, they are transported to the building site. Here, the assembling of the modules takes place, connecting necessary mechanical, electrical, and plumbing. The method of construction of modular structures differs from that of conventional structures. However, in addition to other building codes, (which we will discuss later), modular structures must follow the same building codes as conventional structures.
If you are familiar with modular construction, you’re most definitely aware of the flurry of advantages there is to boarding the modular construction train. Some of the benefits are:
As we all know by now, modules are prefabricated and transported to the building site. Hence, reducing construction and on-site time. If you involve a structural engineering firm that practices division of labor, the firm can assign its members to pour foundations at the building site, build basements of other utilities, while the building construction is going on at the factory site. Past experiences with conventional structures show that an average structure takes close to 30 weeks for completion. While modular construction takes about 10 to 20 weeks for factory assembling and 7 to 14days for onsite assembling.
Modular construction results in high-quality structures since this type of construction involves assembling modules in controlled factory conditions. Also, good storage of building materials ensures high-quality structures. And with construction in controlled conditions, storing building materials is made easy by eliminating the worry of mold or yeast infection, contaminants, and corrosion that can come with storing building materials onsite.
A modular home has an inherent green design property. Although the installation of green elements is possible in a conventional home, its construction process is, however, not green. On the other hand, the construction process of a modular building is green, in the sense that its construction is in a quality-controlled environment.
As you would expect, modular construction would not work for all hotel types. Generally, the dimension of shipping containers and transportation limits, greatly affect the type of hotels that can support this construction approach. Hotels with smaller guestrooms are most suited for modular construction.
There is a common belief that modular construction costs less than conventional construction. And rightly so. However, to develop the right cost comparison, there are many factors the hotel owner and/or cost estimator needs to consider.
Conventional construction requires structure units to be built, most times, one after the other. And modular construction, as we all know, involves the prefabrication of modules. In this case, the cash flow might be more front-loaded than the conventional. Albeit, based on the agreed payment structure.
Another factor is the difference in construction materials for the two construction approaches. Most conventional hotels use concrete. And although these materials might have cost similarities, its cost of installation would differ.
Hence, performing a comparative cost analysis is imperative before jumping on the high rise steel-framed modular wagon. This would help you determine if going modular is the best option for your project or not.
If you are in a seismic zone, this part of this article might interest you the most. As you would most likely guess, modules designed for seismic zones differ from that of non-seismic zones. For seismic zones, structures need to be able to resist seismic loads. In this case, structural engineers decide which module is responsible for resisting seismic loads and which is responsible for transferring seismic loads.
Modules tasked with transferring seismic loads might need to be less stiff. Hence, giving birth to a transportation challenge. Since the modules need to be transported to the site, a stiffer module is best suited to survive transportation stress. A significantly stiff module would result in twisting and cracking of the modules.
High rise steel-framed modular projects require the approval of two separate agencies. Hence, the complexity of the whole permitting process.
One necessary point for hotel owners to note is that the agency for module regulation is different from the local building department, which would normally handle permits for conventional structures. Because of the method of construction of modular structures, the modules reach the building site in an enclosed form. An on-site building inspector might not be able to tell how the walls have been assembled. Hence, the difference in the set of regulations and mode of inspection.
Basically, the approval processes include;
With a different set of regulations comes a different set of requirements and documents. On meeting the requirements, you get a seal of approval, that certifies the modules for installation.
Sometimes, what is reviewed by one agency superimposes the other. For example, approving the fabrication of necessary modules is done by the state-level modular inspectors. The local building department is tasked with inspecting the guestroom’s accessibility or even electricity and plumbing. In other words, every calculation involving connections and capacities needs to pass through both reviewing agencies. This makes obtaining permits a lot more complex. Designers are now required to produce documents that suit the needs of both agencies.
Experts predict that in the nearest future, there might be construction approaches with high productivity gains and reduced costs. Currently, the interest in steel-framed modular construction is primarily from the fact that this approach boasts of benefits like reduced cost and high quality.
In Spite of the increase in the level of interest, high rise steel-framed modular construction is a very selective construction approach and might not suit specific building types.