Public Access and Protection Solutions

While originally designed for the variable and unpredictable world of construction, many of the same features that make modular scaffold indispensable on the job site make it just as applicable for use in publicly accessible structures, such as stairs and pedestrian ramps. Allowing for rapid assembly, easy reconfiguration, and seamless integration into diverse architectural environments, with the correct application and oversight, modular scaffolding can be a powerful solution for the re-routing of pedestrian traffic during temporary closures. Some excellent examples of this are scaffolding used for Overhead Protection Canopies, Public Access Stairs, and Public Access Ramps.

It should come as no surprise that the key features that make modular scaffolding attractive, its versatility and strength, make it a desirable option for temporary stairs and access ways. Composed of modular prefabricated components, the equipment necessary to erect a scaffold stair or ramp in nearly any configuration is often readily available and easily deployable. Not only is it easy to install, but modular scaffolding has the inherent feature of being strong for its weight. This comes in handy when dealing with the relatively high loads required by the various building codes, which we will touch on later.

A very common public-access use for modular scaffolding is Overhead Protection Canopies, also known as OHPs or even pedestrian tunnels. Very commonly found in busy city centers, pedestrian canopies are constructed in busy pedestrian traffic areas to protect the public from potential falling hazards from adjacent work high above. Due to this intended use, the required design loading can be significant, with a typical required design load of 150 psf per the International Building Code (IBC) or even higher in some jurisdictions. Not only are the design loads high, but often there are existing planter boxes, fire hydrants, or parking garage openings that the canopy must work around. It is in these cases where the modular scaffold’s flexibility and strength shine. When properly designed and installed, not only is it able to hold these high loads, but installation in the field can be as simple as swapping component lengths to work around obstacles. DHC completes dozens of OHP designs a year all over the United States, ranging from very simple linear runs to extremely complex designs with multiple space, height, loading and access constraints.

An increasingly popular use for modular scaffold in the public access realm is serving as replacement stairs and ramps when the primary method of access either needs to be moved or has been fully removed. This can be as simple as just a few steps up through a side door, to something as complex as a multi-bay wide staircase reaching multiple floors. Since they are open to the public, compared to a typical construction stair tower that is only accessed by workers on a controlled construction site, not only do these systems need to be designed to support code-required loading for stairs, often times 100 psf or more, but all public access points into and out of a structure must meet ADA requirements. This includes, but is by no means limited to, needing to meet all rise-run limitations, maximum step height and depth limitations, as well as all standard width and landing size requirements. A good example of both the versatility of modular scaffold, as well as the complexity a public access stairway can take, is the ADA ramp and stair constructed at the Portland International Airport. Constructed to allow traveler access into and out of the terminal while the main access way was under construction, the scaffold had to be designed under the same restrictions as a permanent stair and ramp system. In the end, it worked flawlessly.

As touched on in earlier sections of this blog post, while modular scaffolding is an amazing tool that can be deployed for public access, due to the special requirements that come with overlapping into the public space, certain considerations must be made. The most important and critical thing that must be kept in mind is the modular nature of systems scaffold. While the various components provide a massive advantage that builds in flexibility, due to the pre-manufactured nature of the components, it also limits the system to certain orientations that may not fit within the required space. Similarly, while some companies fabricate and install a “Code Compliant” scaffold system with all parts pre-manufactured to meet IBC code requirements, it is on the designer and installers to ensure the transition from the scaffold to the main structure is also code compliant. Depending on starting elevation, ground surface, and floor heights of the structure, this can be an especially complex challenge.

Another aspect that should be taken into consideration is that due to the enforcement of stricter building code requirements, lateral forces often have an increased impact on the design of these structures. While most construction scaffolds do not need to be designed for seismic or high wind forces due to their relatively short time in use and the strictly controlled access, that is not the case for public access scaffolds. Since public safety is paramount, public access scaffolds must go through the same rigorous lateral analysis as a permanent structure, meaning these scaffolds typically require significantly more diagonal bracing and lateral support than a construction scaffold. Anchorage down to the ground is often a topic that is overlooked and can lead to complications. To resist the accumulated lateral loading, the scaffold will often need to be anchored down to an existing slab but in some cases could require their own foundations to be designed, sized, and poured.

Modular scaffolding is an amazingly versatile system, and if designed correctly with the adequate focus on the potential complications and pitfalls of using it in the public sphere, it can be a fantastic solution for public access!