Archive for the ‘Shoring’ Category
February 26th, 2013 by Tracy Dutting-Kane, P.E
How to Ensure Safety While Shoring an Existing Structure
Shoring existing structures can be a tricky business. Typically, the older the building is the more complicated the shoring of it can become. Many older structures do not have drawings of the existing construction and if they do, they are not always reliable. Many buildings go through generations of remodel with additions, renovations and improvisations that are not always documented or constructed properly. Without proper documentation, it is sometimes tough to determine the load bearing members in an existing building which makes it challenging to shore it properly. Difficult access to these documents does not give you a free pass on when and where to shore. If you can’t figure out where the loads are concentrated, you can’t figure out how to safely support anything.
When undertaking the task of shoring an existing structure, you should consider consulting a Professional Engineer – and I don’t just say that because I happen to be one! The peace of mind that you get from entrusting this work to an engineer far outweighs the risk of liability if something were to go wrong during the shoring operation. An experienced professional can help you determine not only how to safely shore the structure, but how to do it in the most economical way possible.
Pertinent information that you will need to know before starting a shoring plan includes but is not limited to: the type of work being performed, the boundaries of work, distance to any excavation, dimensions of the building and location of load bearing members. Other relevant information includes the dead load of the supported area and any anticipated live loads. Examples of live loading conditions that need to be evaluated include determining whether the office building or parking garage will remain operational during construction. You also need to consider if there are any special circumstances such as required access openings in the shoring plan or work sequencing that would affect the standing shores. Do snow and wind loads need to be taken into account? Be certain to consider all of these circumstances when developing the conceptual shoring design. Drawings, schematics and photographs can be provided to convey most of this information. However, in some cases it is easier and more cost-effective for the engineer designing the shoring plan to visit the site.
If you do not follow the correct protocol and improperly shore an existing structure, there is increased likelihood of damaging the building or of a complete collapse during construction. Choosing to retain the services of a Professional Engineer and providing them with as much accurate information as possible will help minimize risks and ensure the most accurate and economical design possible. Don’t take chances; if in doubt regarding the stability of a structure, always err on the side of safety. Get a Professional Engineer involved and maximize your chances of shoring success!
May 1st, 2011 by David H. Glabe, PE
An argument for re-establishing the Shoring & Forming Council in the Scaffold and Access Industry Association.
I recall my first involvement with the Scaffold Industry Association, SIA, in the early 1980’s. I was impressed by the people who were genuinely involved in making the use of the scaffolding and related products safer. I also recall how I was railroaded into taking the minutes for council meetings! In fact, I was inducted (or abducted) into the role of scribe for the Shoring and Forming Council. You read that correctly. Back then there was a Shoring and Forming Council. There also was no Fall Protection Council, Aerial Lift Council, or Hoist Council. Over the years the focus of the association has changed, evolving into an organization that emphasizes the various forms of access for workers. Concurrently, shoring and forming slowly diminished in scope and involvement to the point that it is no longer represented in the SIA.
This doesn’t mean that there are no members who are involved with shoring and forming. It also doesn’t mean that there are no issues with the use of these products. In fact, there actually is more commonality between scaffolding and shoring than you might think. On the other hand, scaffolding is definitely not shoring and shoring is not scaffolding. For this discussion, we’ll leave wall formwork alone except for the fact that the work platform on a wall form is a scaffold and consequently the scaffold standards in federal OSHA 1926, Subpart L apply.
What are the common elements between shoring and scaffolding you may ask? Well, fall protection is a common element; access is a common element; falling object protection is a common element; and, capacity and strength are common elements. The significant difference between scaffolding and shoring is that a scaffold is a temporary elevated platform and its supporting structure used to support workers or materials or both. Shoring, on the other hand, can be a system of structural elements used to support the formwork for concrete (the Jell-O® mold that holds the liquid concrete). Shoring can also be a system of structural elements used to support existing structures such as buildings while repairs or modifications are being performed. Since shoring and scaffolding are different structures, different OSHA standards typically apply although there is overlap in a number of areas. That is where the similarities come into play and thus it makes sense that the SIA should consider resurrecting the Shoring and Forming council.
For example, fall protection for shoring erectors has the same issues as fall protection for scaffold erectors. For new concrete construction, the shoring equipment is always at the top of building (that is logical) and consequently, there is no convenient anchor above the erectors unless the Goodyear® blimp is in the neighborhood. Supported scaffolding can have the same issue. Interestingly enough, a review of the OSHA standards show that the Construction Industry fall protection standards are applied by OSHA through the use of Letters of Interpretation. Unfortunately, it is a circuitous route that attempts to apply the standards in creative ways so as to justify a desired outcome. The results are confusing requirements for shoring erectors to contend with during their work.
Access for both scaffold erectors and shoring erectors is an intriguing topic for those who attempt to apply inappropriate standards. OSHA considers shoring frames to be working surfaces and therefore fall protection and/or positioning devices are required. If these same frames are used as scaffolding, and they can be, then they can be climbed by the erectors. Confused yet? Wait—there’s more! Access for shoring can really be interesting. While the erector shouldn’t climb the frame because it is not a ladder but rather a working surface, the erector doesn’t need to comply with the ladder standards because his access continues to move while the shoring is constructed and the access requirements of 29 CFR 1926-Subpart X were never intended to apply to this work activity. Are you confused yet?
The final frustration is when the compliance officer or site safety employee can’t figure out whether you are working on scaffolding or shoring. Applying the scaffold standards to the erection of shoring is like trying to apply the fixed ladder standards to a scaffold attachable ladder—it doesn’t work.
The Scaffold Industry Association members have a wealth of experience and expertise that can be used to clarify the intent and application of the standards while making life easier and safer for both the erectors and users of temporary structures. Is it time to resurrect the Shoring and Forming Council? I think it is.
July 1st, 2008 by David H. Glabe, PE
So, what has the association been up to for the last 25years? Back in the early 1980’s the big issues were insurance, OSHA, CAL-OSHA, liability exposure and membership. Sounds familiar doesn’t it? But wait a minute; it isn’t the same issues although the agencies may be the same. Federal OSHA was only 13years old and the agency was in the process of revising the scaffold standards. The scaffold industry was operating under the difficulties and confusion of the original specification standards. Cal-OSHA’ relationship with the SIA was congenial (as far as I could tell from 1000 miles away) and the liability issues were being addressed through the development of Codes of Safe Practices. The association was entering its second decade and the membership was growing. Since that momentous occasion when I was the scribe of the Shoring Council, the association has certainly had its low points and high points. But there is no doubt that the high points greatly exceed the low points. The fact that the association has survived some of those low points illustrates not only the tenacity of its members but the value of its existence. We were on a roll back then, just as we are now, but in a different way. At that time, we were almost a decade away from initiating the SIA training program as we know it today. But the foundation for that program was being laid through the development of 35 mm slide shows (remember those) and the Codes of Safe Practice. Just as now, members donated countless hours to the SIA for the sake of those who use scaffolds. There is no way to measure the effectiveness of those efforts since we only measure injuries and deaths and scaffolding still shows up on the “Top Ten” in OSHA fatality statistics. But one has to wonder where we might be without the efforts of those early members who contributed so much to the industry.
It is a comfort to see a reinvigorated membership improving the safety of the industry. Back in the early ‘80’s, frame scaffolds dominated the market. Systems scaffold was a relatively new product and aerial lifts were in their infancy, at least compared to today. Scaffold erector fall protection was just beginning to become an issue for the industry. At that time the bigger issue was getting the scaffold users to use guardrails; some things never change.
Denver has changed since the early ‘80’s too. We were known as a “cowtown” to some, the “QueenCityof the Plains” to others. Coloradohas added over a million folks to its population since 1983, greatly changing the size and feel of the city. We have the Sixteenth Street Mall, which didn’t exist at the last convention. The present convention center didn’t exist either. There was a convention center but we tore it down because we didn’t like it. I can’t promise perfect weather but it usually is pretty nice in July. Besides, you can always head to the mountains if it gets too hot in the city. (For those of you from locales that have an elevation less than 4000 feet, you’ll appreciate the lack of humidity—we have a law that doesn’t allow it to go above 50%.)
For those of you who like gambling, Colorado has a couple of towns not too far up the canyon that lets you leave money for us but my suggestion is don’t bother—just give me the money and I’ll save you the trip. Just kidding, I don’t want the Chamber of Commerce to be mad at me. Go to Blackhawk and Central City and gamble. Take the “Oh myGod Road” out ofIdahoSprings up into Central City. The drive is a thrill and a gamble. When you get to Central City go gamble at the tables. It may be low stakes but its fun. (Russell and Gregory Gulches, where Central City is located, are where the big gold finds of the 1850’s occurred. In fact, Central City is known as the “Richest Square Mile on Earth.”) Or, if you don’t like the idea of gambling, try out driving the Lariat Trail up to Buffalo Bill’s grave. The view of the city from Lookout Mountain is fabulous. The road starts out in Golden, the gateway to the west, and home of the world’s largest brewery, Coors. Speaking of beer, Denver is also home to more micro breweries than anywhere else in the country which, of course, should keep a few of you occupied for the entire convention.
If you like hiking, we have lots of opportunities. If you are adventurous, try tackling a fourteener-we have 52 of them. These are mountains over 14,000 feet high. Not so adventurous? Then drive to the top ofMt.Evans, one of the fourteeners and the highest paved road inNorth America. You can say you did a fourteener; I won’t tell.
By the way, we have lots of construction going on. Admire how we do scaffolds inDenver. They are unique because they are always much taller than the rest of the scaffolds inNorth America; we start out a mile high! Welcome to theMileHighCity, theQueenCityof the Plains, and the host city for the Scaffold Industry Association 2008 Convention; we the proudColoradomembers of the Scaffold Industry Association are pleased to have you. Let’s continue what was started in California in 1973, added to in Denver in 1983, and goes on today, better than ever!
April 1st, 2003 by David H. Glabe, PE
When is a platform a work deck and when is it formwork? This question is frequently asked during the process of erecting shoring equipment. A similar question is whether the equipment is scaffolding or shoring. Often the situation is misdiagnosed and the ensuing conversation concerning the application of regulations develops into a frustrating exchange of accusations.
Is there any significance to ascertaining the difference? Is the safety of the erector or user adversely affected? What role does the type of equipment have in determining the outcome? These are good questions that require answers.
The first step is to determine the basic difference between a scaffold and a shoring deck. As defined by the U.S. Federal Occupational Safety and Health Administration, OSHA, a scaffold is any temporary elevated platform and its supporting structure used to support workers and/or materials. A shoring deck, on the other hand, as described by the Scaffold, Shoring and Forming Institute, SSFI, is the sheathing, joists and stringers which act as the mold for liquid concrete. This mold is also commonly known as the formwork. These definitions surely indicate that there is a significant difference in the two definitions. So why the confusion? It begins with the fact the workers stand on both a “temporary elevated platform” and the formwork of a shoring deck. In essence, it appears that the shoring deck is a temporary elevated work platform.
Therefore, the second step is to look beyond appearances and perceptions to determine the purpose of the deck. Ask the basic question: What is this temporary structure for? Will this deck be used for workers to obtain access to their work or is this deck being used to support concrete. It doesn’t get any easier! If the deck is being used to support concrete, the workers are there doing work to the deck. If the deck is being used as an elevated platform, the workers are doing work from the platform.
The third step is to properly apply the standards. Here’s how it works. For shoring, use these US Federal OSHA standards:
For fall protection, 29CFR1926, Subpart M:
For access, use 29CFR1926, Subpart X:
For concrete and formwork, use 29CFR1926, Subpart Q.
For scaffolding, use these standards:
For fall protection, 29CFR1926, Subpart L;
For access, use 29CFR1926, Subpart L, unless you are using a portable or job built ladder, then use 29CFR1926, Subpart X;
For scaffold construction and use, use 29CFR1926, Subpart L.
What could possibly be the difference. The first is fall protection. Subpart M requires fall protection at 6 feet above the lower level. Subpart L requires fall protection at 10 feet above the lower level. This means that a scaffold platform must have fall protection once that platform is more than ten feet above the level below while a shoring deck requires fall protection at six feet. The second significant difference is in the safety factor. For scaffolding, the minimum safety factor is 4. For shoring and formwork, OSHA does not specify a safety factor although the American National Standards Institute, the SSFI, and others specify a range of safety factors of 2 to 4, depending on the component.
Keep in mind that it is not the type of equipment but rather the intended use of the equipment that determines applicable safety regulations. In other words, scaffold frames can easily be used as shoring. In this case Subpart M would apply for fall protection. Conversely, shoring frames used to support several plank for workers to use to access the top of a column would be scaffold and all the applicable scaffold standards would apply, including plank placement, access, safety factors, and fall protection. Just because the workers are standing on a tower normally used for shoring will not exempt them from the scaffold standards.
Perhaps the most problematic aspect of distinguishing between a shoring deck and a scaffold platform occurs at the work platform that typically surrounds the edge of the shoring deck. More specifically, how is the safety factor applied to the entire system? Those components supporting the work platform require a 4 to 1 safety factor while those components supporting the remainder of the deck typically require a 2 to 2.5 safety factor. Usually this is not of concern since the shoring is required to support loads that are much higher than those of a work deck. However, as with all scaffold and shoring designs, a qualified person will properly design the system.
March 1st, 1999 by David H. Glabe, PE
Is it scaffold? Or, is it shoring? Is there a difference? Of course there is a difference. Scaffolding is an elevated work platform and its’ supporting structure, used to support workers, materials, or both. Shoring is the assembly of vertical legs, horizontal members, and formwork, that is used to support concrete or other loads. The significance of all this is the ramification that the industry and OSHA standards have on the installation and use of the equipment.
Simply put, if the installation is classified as scaffolding, entirely different standards apply than if the installation is classified as shoring. Two issues, worker safety, and compliance with applicable standards, are involved. Viewed from the perspective of worker safety, there really isn’t much difference between shoring and scaffolding. After all, both utilize similar equipment, and in fact, at times the equipment is identical; in other words, scaffold frames can be used for supporting concrete while shoring frames can be used to support work decks. Viewed from the perspective of Standards compliance and enforcement, surprising results can occur, especially if the individual applying the standards is not familiar with either the standards, the distinction between scaffolding and shoring, or both.
Looking at worker safety first, both scaffolding and shoring present exposures to workers that must be addressed. The primary hazard is falls, caused either by poor access, or while working at heights. The exposure is the same for shoring or scaffolding since both are typically erected in a similar manner. Erectors are exposed to falls while erecting the individual legs or frames. Erectors are also exposed to falls while assembling the deck, whether it is the formwork deck or a scaffold work deck. Because of this, the exposure should be limited to only those erectors who are trained in hazard recognition and proper equipment handling and erection; erectors not involved with the leading edge work should be protected from exposed edges of decks. If adequate anchors, either designed for the loads or strong enough to support 5000 pounds, are available, they should be used by the erectors to attach personal fall protection equipment. (Scaffolding and shoring towers that are not designed as anchors should not be used as anchors.) It is interesting to note that typically, shoring towers cannot be fall protection anchors because they are usually free standing.
Compliance with applicable standards, regulations, and industry practice is straightforward provided that the intent of the standards is not forgotten. The standards exist because of known hazards. It can’t get any more simple! Problems arise when workers and standards enforcers do not understand the intent of these standards. Taking the Federal Occupational Safety and Health Administration (OSHA) standards as an example, compliance becomes very confusing if you do not understand that there is a difference between shoring and scaffolding. Subpart Q, Concrete and Masonry Construction, which applies to shoring, has no specific standards addressing the erection of shoring and formwork. Instead, fall protection for workers on the formwork deck is addressed in Subpart M, Fall Protection, since the formwork deck is considered an open sided platform. Conversely, since scaffolding is excluded from Subpart M, you must go to Subpart L, Scaffolds, to find the standards that apply to fall protection for workers erecting and using scaffolding and scaffold work platforms.
What about access? This gets a little trickier since both shoring and scaffolding erectors are responsible for constructing proper access for users of the shoring and scaffolding. Similar to fall protection, there are no requirements in Subpart Q that specifically address the installation or use of access for shoring erectors. However, Subpart X, Stairways and Ladders, does address this issue: “A stairway or ladder shall be provided at all personnel points of access where there is a break in elevation of 19 inches.” This is great for platforms and floors, but what about the erector of shoring equipment who must climb individual towers to erect the frames, stringers and joists? The standards are silent on this matter. Fortunately, this issue is addressed for scaffold erectors in Subpart L. The competent person determines proper access for the erector. As an erector, normal industry practice is to follow the same guidelines for shoring. However, from an enforcement standpoint, the standards of Subpart L cannot be applied because shoring equipment is not scaffolding equipment. Therefore, Subpart L standards cannot be applied to shoring any more than Subpart Q standards can be applied to scaffolding.
So, what’s the answer here? Remember, shoring is not scaffolding; scaffolding is not shoring. Keep the following in mind when reviewing potentially applicable standards and regulations:
1. The type of equipment does not define the classification of shoring or scaffolding. The activity defines the classification.
2. Fall protection measures and access for erectors are to be determined by the competent person, for both scaffold and shoring erectors. Note: The Subpart L standards specifically address fall protection and access requirements for scaffolding erectors; there are no specific standards that address fall protection and access requirements for shoring erectors.
3. Standards for the application and use of shoring are found in Subpart Q of the federal standards.
4. Standards for the application and use of scaffolding are found in Subpart L of the federal standards.
5. Shoring formwork decks are considered open sided platforms; consequently fall protection for users (but not necessarily erectors) of the platform must be provided when the deck is more than six feet above the next level (Subpart M).
6. Erectors of shoring are exposed to the same hazards as scaffold erectors and the Subpart L standards for scaffold erectors can be excellent guidelines (notice I said guidelines, not standards or laws) for shoring erectors to use.
7. Subpart L standards do not apply to shoring and therefore are not enforceable for shoring applications.
8. Common sense dictates that all scaffold and shoring erection must be done by trained and experienced personnel under the supervision of a competent person.
9. Subpart X, Stairways and Ladders, clearly was not written with shoring erectors in mind. Therefore, no Subpart X regulations specifically apply to shoring erectors.
10. Although workers will be on a formwork platform installing edge forms and rebar, the deck is a formwork deck, not a work deck.
11. Don’t lose your focus. The whole idea is to protect workers, both users and erectors. Consider the options, minimize or eliminate the hazard, and provide training. Training is the best protection a worker can have.