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Shoring

I’m Digging Your Shoring Plan!

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Due to the complexity and property line constraints of modern construction, earth shoring requires a solution that must conform to both engineering and safety guidelines during all stages of construction.

Here are the 5 key concepts to remember for an earth shoring design:

1. Applicable codes: The type of project will define the requirements for an engineered earth shoring plan. For instance, a design that allows for inches of deflection at a multi-story urban high-rise may not be compatible with AREMA requirements for railroad earth shoring. While a contractor may be able to get away with using a cantilevered design, a similar design that incorporates the locomotive surcharge loads into the analysis may fail simply by being out of tolerance for railroad deflection guidelines. In this case, the common solution is to add soil anchors to keep the design in compliance.

2. Material: This is typically a contractor preference. If a contractor has a substantial inventory of steel I-beams/H-piles and wood lagging, it is in the best interest of the client for the engineer to design the system accordingly. Piles may need to be spaced more tightly and the design may not be as efficient as sheet piles, but it does eliminate the need for the contractor to spend more money.

3. Sequencing: With most earth shoring designs, there is a sequence of installation that must be followed based on the applied loads that change with depth. For example, in a cofferdam design, if wale frames are required, the contractor may have to install the wale at a specified elevation prior to proceeding. This elevation may be above the final excavation depth, but the engineer should have determined that this is the maximum depth that the shoring can support in a cantilevered condition and/or without restraint at the base. This may be a result of deep excavations where the substrate alone at the base is not adequate to support the lateral load. Oftentimes, many scenarios must be analyzed to ensure that the members are not overloaded and the entire shoring design is code-compliant at any given stage.

4. Embedment Depth: As a general guideline, the minimum embedment depth of a pile must be 75% of the retained height to ensure adequate development and base restraint.

5. Workers at the Top of the Excavation:  While the designer may account for the surcharge loads at the top of the excavation, it is also important to consider the impact of workers. If a guardrail is required based on project conditions, then it must be OSHA compliant and any loads/connections required shall be accounted for in the design of the pile. Common practice is to weld a guardrail post at the top of the pile, but this must be checked not only for load application, but also for maximum spacing.

Engineered shoring plans are critical components of construction plans, and a well-thought out design will save the contractor both time and money. As the saying goes,”Think before you dig!”

5 Impressive Things Built (or Fixed) Using Cofferdams

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Everyone knows about dams. But have you heard about a cofferdam?

Cofferdams have been around for a long time. People have used these when excavating very large plots of land or building foundations of water-based structures such as bridges or piers. The cofferdam keeps water from flowing into these sites, ensuring a dry foundation.

The cofferdam has been used to build and fix some impressive things. Check out the five most inspiring objects constructed by using these fascinating dams.

5 Impressive Things Built (or Fixed) Using Cofferdams

Cofferdams have helped civilizations divert water, gain new territory, build dry structures safely, and even recover history. They can be as simple as a pile of sandbags set up to use as a barrier during wartime or complex as a double sheet piling used in modern-day bridge construction.

While today the cofferdam is particularly useful for earth shoring engineering projects, it continues to be used in the engineering world as a helpful tool in water diversion projects.

1. Battleship U.S.S. North Carolina

Because ships are a water-borne craft, their preservation often depends upon a dry work environment. When it comes to this battleship located in Wilmington, North Carolina, the use of a cofferdam will integrate a memorial walkway for visitors and water-free access to the battleship for preservation and repair work.

The project, nearly six months away from completion, is unique because it won’t rely on the cofferdam for underwater construction. This battleship will be open to visitors and kept looking sharp above water.

While this battleship will cost a hefty $8 million, it will, in fact, be a permanent installment. This is another great aspect of the cofferdam: it can be both temporary or fixed. The permanent cofferdam enables future maintenance and repair work on structures like the U.S.S. North Carolina.

2. The Hoover Dam

It may seem counterintuitive to say that dams are made by using dams. But with this impressive dam that’s become an icon of the American road map, cofferdams were a huge part of the construction.

The Hoover Dam construction was an architectural and engineering feat in Nevada in 1933. Before the dams were installed, workers removed 250,000 cubic yards of silt from the river in order to ensure a solid starting foundation.

Two cofferdams were required to make sure the construction was dry and water-free. Both were made from earth and rockfill, and relied on an additional rock barrier to prevent any additional water seepage. While some people were worried that the spring Nevada floods may damage all of this foundation pre-work, the damming worked and construction went along as planned.

3. Ancient Roman Bridges

When we said that the cofferdam has been around for a really long time, we meant it. For thousands of years, civilizations have found the cofferdam useful, and you see this in many of the bridges of Ancient Rome.

Early populations relied on more basic forms of the cofferdam in order to control waters for drinking supply, irrigation, and land control. Often this entailed the diversion of a river. Legend has it that King Cyrus of Persia used the cofferdam in order to divert the Euphrates River in his pursuit of the city of Babylon. This meant that an entirely new empire was established based off of the use of this dam alone!

Similarly, the Romans made use of this handy type of damming when bridging the Danube River. Trajan’s Bridge, built as a result of cofferdam wood pilings, enabled the Romans to travel to contemporary Romania. This bridge totaled nearly 4500 feet in length.

4. The Tapan Zee Bridge, New York City

The Tapan Zee provides a great example of how cofferdams still help with important construction feats today. This incredible bridge spanning the Hudson River cost nearly $4 billion to construct. Its completion would not have been possible without the use of the cofferdam.

A complex software was used to design the steel dams, 90 feet by 45 feet, used in construction. The software also took soil type into consideration. Because the Hudson contains a lot of river silt and soft deposits, the Tapan Zee dams had to be backfilled in order to create a solid base for the bridge piers.

5. The La Belle ship

The La Belle shipwreck has long been an icon of the Texas coast, and the cofferdam made sure that La Belle remained a fixture of seventeenth-century history.

In 1687, this ship crashed along the shoreline as a result of poor weather and difficult seas. Manned by a New World explorer, this ship was the last of four ships sent to explore the unknown coasts. When La Belle crashed and sank, it became sealed in mud for over three hundred years.

In 1995, an archeological team discovered the site of La Belle’s sinking. Such a recovery requires a lot of complicated engineering. The Texas Historical Commission constructed a cofferdam system around the sunken ship. This elaborate system cost over $2 million.

The mission was successful, and in 1997 the full extent of the treasure was known. Hundreds of incredibly preserved artifacts and much of the ship’s original structure were recovered. If it weren’t for the cofferdam, we would never know this history.

Cofferdams of the Future

There’s no doubt about it: the cofferdam is versatile, useful, and amazing. It has enabled people to bring history back to the surface, cross rivers, and construct impressive architecture. The cofferdam will continue to be an essential part of contemporary engineering projects.

At DH Glabe & Associates, cofferdams are our bread and butter when it comes to earth shoring engineering. To date, we’ve completed over five thousand company projects in thirty-two years, relying on the expertise of over fifty professional licenses. We assist with both civil and commercial projects using a variety of technology, including H-piles, mechanically stabilized earth walls, sheet piles, geofabric, and secant pile walls.

Earth shoring is not all we do. No matter the size or type of your engineering project, at DH Glabe & Associates we pledge to be with you every step of the way. Contact any of our construction engineering experts today to learn about what we can do turn your project into a reality this year.

Existing Structure Shoring

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Shoring existing structures can be a tricky business and the older the building, the trickier 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 properly.  Without proper documentation, it is sometimes difficult to determine the load bearing members in an existing building and this makes it difficult to shore.  If you can’t figure out where the loads are concentrated, you can’t figure out how to safely and economically support anything.

When undertaking the task of existing structure shoring you should consider consulting an engineer – and I don’t just say that because I happen to be an engineer!  The peace of mind that you get from entrusting this work to an engineer far outweighs the risk of liability if something goes wrong during the shoring operation. 

Things that your engineer will need to know before starting a shoring plan include 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 pertinent information includes the dead load of the supported area and any anticipated live loads – for example, will an office building remain occupied or is your customer trying to keep the parking garage operational during construction?  Depending on the scope of the job, snow and wind loads may also need to be taken into account.  Be certain to consider any special circumstances like required access openings in the shoring plan and work sequencing that would affect the standing shores.  Drawings, schematics and photographs can be provided to convey most of this information but, in some cases, it is easier and most cost effective for the person designing the shoring plan to visit the site.

If an existing structure is improperly shored, there is danger of damaging the building or of a collapse.  Providing as much accurate information as possible to your shoring designer will help to minimize risk and ensure the most accurate and economical design.  Don’t take chances, if in doubt get a professional engineer involved and maximize your chances of shoring success!

Shoring Existing Buildings and Structures

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When shoring is mentioned, new buildings typically come to mind. However, shoring is also frequently used to support existing buildings, either because the building is failing or building modifications are being performed. While supporting existing buildings utilizing standard shoring equipment performs the same function as new construction—the approach to the design and installation oftentimes is entirely dissimilar.

Shoring existing structures can be a tricky business and the older the building, the trickier it can become. Many older structures have unreliable drawings or none at all of the existing construction. Additionally, many buildings go through generations of remodel including additions, renovations, and improvisations that are not always properly documented. In fact, without proper documentation it becomes difficult to determine the location of the load bearing members in an existing building and consequently complicates the designer’s shoring design and analysis. Simply stated, if the location and magnitude of the loads are unknown, it is impossible to safely and economically design a shoring system.

Qualifications and Requirements

As with scaffolding, all shoring must be designed by a qualified person. Additionally, the services of a qualified engineer will most likely be required, particularly if columns and footings are removed. Load transfer from columns can easily reverse the stresses in the adjacent beams; if the shoring isn’t placed correctly, and any excessive stresses mitigated, structural components and the shoring equipment may be compromised to the point of failure.

Items the engineer will require before initiating a shoring design and analysis include 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 pertinent information includes the dead load of the supported area and any anticipated live loads— for example, will an office building remain occupied or will the parking garage remain operational during construction?

Depending on the scope and duration of the project, snow and wind loads may also need to be taken into account. Be certain to consider any special circumstances like required access openings within the shoring equipment and the sequencing of the work which could affect the shoring towers. While drawings, schematics, and photographs can be provided to convey most of this information, in some cases it is easier and more cost effective for the engineer designing the shoring plan to visit the site.

Improper Techniques Can Prove Catastrophic

The consequences of an improperly shored existing structure can be, and usually are, catastrophic. Reports of partially or completely collapsed structures are common and are typically the result of either a poor or non-existent design produced by an unqualified person.

Simply sticking a few shoring posts under the joists and beams in a random fashion, based “on experience,” does not a good shoring plan make! Worse yet is the construction crew that installs various posts in an ill-defined manner, only to be surprised by creaks and groans of a structure that is ready to fail. While the structure is talking to them, they misread the message, only to find that total collapse is imminent.

To avoid such an experience, providing accurate and complete information to your shoring designer will eliminate the risk of collapse and ensure an accurate, safe and economical project. Don’t take chances, if in doubt get a qualified professional engineer involved and maximize your chances of shoring success!

Shore Enough, It’s Scaffolding

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Regulatory Differences Between Shoring and Scaffolding

It is not all that uncommon for a scaffold equipment supplier to also be a shoring equipment supplier. After all, both are used on a temporary basis, have similar components and are designed to support loads. While shoring equipment normally supports heavier loads, scaffold frames can as easily be used as shoring as shoring can be used as scaffolding. (The shoring referred to here is the equipment that is used to either support fresh concrete while it is curing (getting hard) or to support existing structures. It is not the equipment used to restrain soil in excavations and trenches.)

Of particular interest are the applicable regulations for scaffolding and shoring. Is shoring the same as scaffolding? Do the regulations that apply to scaffold erectors also apply to shoring erectors? After all, frame scaffold is just like frame shoring—or is it? These are good questions that deserve accurate answers. The quick, or fundamental answer, is that scaffolding is not shoring and shoring is not scaffolding. Since the work activity, and not the equipment, describes the equipment’s function, it just doesn’t matter if scaffold frames are used to shore up concrete any more than if shoring frames are used to support a work platform.

Applying Federal OSHA standards

Here is how the federal OSHA standards get applied. It is necessary to determine what the elevated platform/deck is being used for. Is this elevated platform used to support employees or materials or both so that the workers can reach the work area? For example, are the employees masons who are laying up brick and block? If so, then the elevated platform, and the supporting structure, is a scaffold. On the other hand, is the primary purpose of the elevated platform to support fresh concrete? If so, then the deck is a “horizontal walking/working surface.” The significance here is that the purpose of the deck must be known so that the correct standards are utilized. What happens when the work surface is used to support employees who are using it to reach a work area and the work surface is also being used to support concrete? What about the walkway around the perimeter of the deck that is used to support concrete? Well, here is how it works: Say that you have an electrician using the deck/platform to reach a location to install conduit and electrical boxes. Since the electrician is using the work surface as a scaffold platform, the platform must be able to support itself and four times the intended load. In addition, the guardrails must comply with the scaffold standards, there must be access in compliance with the applicable scaffold standards and any exposed employees must be protected from falling objects.

On the other hand, if the work surface is being used to support concrete, then it must comply with the applicable fall protection, access and formwork standards that address that work activity, including the concrete and formwork standards, 29 CFR 1926, Subpart Q, the fall protection standards at 29 CFR 1926, Subpart M, and the access requirements found at 29 CFR 1926, Subpart X. Typically, if these standards are met, then in the example where the electrician is using the platform to access her work, she will also be in compliance with the scaffold requirements due to the fact that the scaffold regulations are generally not as restrictive as the fall protection and access regulations for working surfaces.

Where are the Differences?

Where are the differences? For the guardrails, in scaffolding the guardrail height is 38 inches to 45 inches while for an open-sided work surface the range is 39 to 45 inches. Access in scaffold requires that the first step is not more than 24 inches while it is 19 inches for a floor or other work surface. Falling object protection standards are similar for both scaffold platforms and other work surfaces although the safety factor for a scaffold platform is 4 while the safety factor for a deck supporting concrete is whatever the employer feels is correct. (ANSI and the SSFI recommend a 2 to 3 safety factor.)

What should be done with erectors? While the temptation is to consider shoring equipment erectors to be the same as scaffold erectors, and therefore the scaffold standards should apply, the reality is that shoring erectors are not scaffold erectors. Consequently, the scaffold regulations do not apply. This presents a quandary when it comes to the application of the appropriate standards. Is climbing a shoring frame access or a working surface? When do shoring erectors use personal fall protection? Or do they?

Well, here is how federal OSHA views it. A shoring frame is a vertical walking/working surface. Consequently, personal fall protection is required when climbing a frame. Standing on a plank at the top of a shoring tower is considered to be an open-sided platform; fall protection is required. Walking/climbing between shoring towers is not normal access so therefore the access standards would not apply. But the fall protection standards would apply.

As for the walkway around a formwork deck supporting concrete, it is considered an open-sided horizontal work surface. Therefore a guardrail system is expected and it must comply with the regulations in Subpart M where the toprail must be at least 39 inches above the deck and no more than 45 inches.

Focus on Purpose and Safety

Confused? The bottom line is that you need to look at the purpose of the work surface. This will determine if it is a scaffold platform rather than a horizontal work surface. And as for the employees installing the rebar and inserts in preparation for placing the concrete, although they appear to be using that deck to access their work and consequently it appears it would then be a scaffold platform, these employees are doing work to the deck which then makes that deck an horizontal work surface and not a scaffold.

Still confused? Focus on safety—not the regulations.

The Fine Art of Multi-Level Reshoring

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With many variables to consider, there simply does not exist a “one size fits all” approach to reshoring.

To discuss reshore, we must first start with an understanding of shoring, which, according to ANSI A10.9, is “The vertical supporting members in a formwork system.” The important points here are ‘vertical’ and ‘formwork‘, which signify that we are supporting a wet, horizontal concrete slab. Easy enough? Good, then let us move on to reshore.

Reshore, also according to ANSI A10.9, is “The vertical supporting members that are used to support partially cured concrete after the removal of the formwork.” It is the system of vertical load bearing supports that are assembled AFTER the shoring is stripped or released that are intended to carry the partially cured deck or decks.

So when do you need reshoring?

Well, for starters, you do not need reshoring if you only have one slab and your shoring system is supported by the ground or other sufficiently rigid substrate. If your substrate is not sufficiently rigid, you might need reshoring to transfer the shoring loads to the rigid substrate or ground.

Reshoring is required when you are pouring a concrete slab and your shoring system must be supported by lower floors that may not have achieved full strength. It may be necessary to spread the shoring load to more than one of the partially cured slabs or floors below. This is done with reshoring.

You have heard the old saying ‘There’s more than one way to skin a cat’. Well, there is also more than one way to design reshore. Many times, it is based on the shoring designer’s preference, the slab thickness of the supported structure or the load limitations of the equipment to be used.

One approach, the Simplified Analysis, is spelled out in ACI 347.2R. There are several factors to consider but it all boils down to how much load your newly placed slabs can handle and what the load carrying capacity of your shores and reshores are.

The Simplified Analysis starts with several assumptions. First, all slabs are identical. Second, shores and reshores are aligned one-to-one from floor to floor. Third, ground level or other base support is rigid and shores are spaced closely enough to treat the shore reactions as a distributed load. Finally, shores and reshores are infinitely stiff relative to the slab.

The Simplified Analysis assumes that all slabs are identical but we know that in real life this is not always true. If you invest the time and money up front when designing the shoring layout, it will pay off in the end. That means that you must look at all of the levels or floors prior to beginning the shoring design so that you can economize the layout and reuse what you can in the reshore design. It is easiest and cheapest to maintain the same shoring/reshoring footprint from floor to floor. This pre-planning saves design time and labor hours.

The question then asked is ‘Why do you have to loosen then re-tighten shoring to re-use it as reshoring?’ In many cases, you need to loosen or drop the shoring system to allow the slab to deflect to its natural shape so that it can carry its own weight. By allowing the slab to carry itself, we then transfer only the shoring loads from above through the slab and into the reshore system preventing the accumulation of loads. Thus, the reshoring carries the load from only the shored slab.

So when do you not have to loosen and re-tighten shoring to re-use it as reshoring? When the shoring has been designed to carry the accumulated loads from the slab that it currently holds plus the supported slab or slabs above it, the current slab does not have to carry its own weight so there is no need for it to deflect. If the slab does not need to deflect, the shoring does not have to be loosened.

‘Can I always drop the deck and re-tighten the shoring to act as the reshore?’ The simple answer is no, you cannot. You must have the same leg-for-leg pattern for the shoring and reshoring and you must ensure that the partially cured slab can handle the loads imposed from the shoring system. Sometimes, the shored floor above is heavier than the current floor and the current floor slab cannot handle the loads imposed by the upper floor(s). If you do not have a leg-for-leg reshore layout or it is impractical to reshore in a leg-for-leg pattern, an engineer may be able to provide you with a reshore layout based on a structural analysis of the partially cured slab or slabs.

‘Can I always employ the “one level of shoring and two levels of reshoring” rule-of-thumb?’ No, you cannot always employ the same shoring and reshoring patterns. The number of levels of reshoring is based on the strength of the partially cured slab, the design of the structure and the capacity and frequency of the shores. Some structures are designed to allow more loads on a floor slab than others and these things need to be considered when designing a reshore pattern. The thickness of the slab plays a crucial part in the reshore design because the thicker the slab, the heavier the shoring and reshoring loads become which could require more levels of reshoring to handle these loads.

Multi-level reshore requires preplanning to maximize and economize both the shoring and reshoring layouts. Not all projects are the same and all reshore patterns are not the same. There are several factors to consider when determining how many levels of reshore are required for a given project. No matter what design or method of analysis you choose, always utilize a qualified shoring and reshoring designer to save time and money to keep your project safe and on schedule.

Shoring…Are You Protected?

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Applying the correct regulations and working safely while constructing shoring & formwork

When it comes to providing fall protection and access for shoring and formwork erectors, OSHA scaffold standards apply to scaffolding and nothing else; so what does a shoring or formwork erector do? The most efficient answer is to not fall while erecting the equipment.

Shoring Tower or Elevated Work Platform?

In order to apply the correct regulations, the first step in providing fall protection and access for shoring and formwork erectors is to determine if they are actually erecting shoring towers or an elevated work platform so they can reach the work area.

While both scaffold construction and shoring construction involve the assembly of towers, the use of those towers is completely dissimilar. Shoring towers are used to support a deck that is used to support concrete. Scaffold towers are used to support an elevated platform that is used to support workers or materials or both. But aren’t shoring decks supporting workers who are installing the rebar and inbeds? Yes, but those workers are doing work to the deck, not workingfrom the deck. And that’s the big difference.

Once it has been determined that the towers being constructed are shoring towers, and the deck on top is the formwork for the concrete, then appropriate fall protection and access standards can be applied.

The fall protection standards are found in Subpart M of the OSHA construction standards, 29 CFR 1926. The access standards are found in Subpart X of the same standards.

Access or Work Surface?

Are the erectors climbing frames to construct a tower using the frames to gain access, or working on an “unprotected side or edge of a work surface?”

Per OSHA, when the erectors are climbing and assembling the frames, it is a “vertical work surface.” So if an erector is climbing/assembling a shoring frame, it is not access—it is a work surface and fall protection is required to be compliance. It’s reasonable to conclude that both a guardrail system and safety net system aren’t applicable, so that leaves the personal fall protection system to get the job done.

The Challenge

Fall protection is required once a worker is six feet above the level below. The anchor to which the lanyard is attached must hold 5,000 lbs. unless it is designed by a Qualified Person and has a safety factor of two. This can be extremely problematic at low heights above the surface below since it is very rare to have an anchor point above the worker. (Shoring is normally used to construct the top floor of a building with the erectors constantly above the top floor. While dismantling, it is equally difficult, near impossible to provide fall protection at the same low heights since lateral movement and limited fall distance are mutually exclusive—you normally can have one or the other but not both.)

When it comes to providing fall protection for the erectors constructing the deck— installing the joists, stringers, and plywood— there is some allowance for “leading edge” erectors. A leading edge is the edge of the formwork that is constantly changing due to the addition of additional decking. It’s considered to be an unprotected side and edge during periods when it is not actively and continuously under construction. Leading edge erectors are to be protected unless the employer can demonstrate that it is infeasible or creates a greater hazard to use fall protection. It is the employer’s obligation to prove infeasibility, not OSHA’s obligation to prove feasibility.

In a Nutshell

Fall protection is required when a worker is more than six feet above the level below whether on frames, vertical wall forms (except the scaffold platform attached to the wall forms where the scaffold standards do apply), or horizontal formwork—easy in principle, difficult, near impossible to execute. A company’s Competent Person is the one responsible to evaluate the situation and determine the applicable regulation.

While fall protection will keep you from falling off an elevated surface, proper access is necessary while getting to that work surface. Access is straightforward; if you are using a portable ladder, you must comply with the manufacturer’s recommendations and the regulations found at 29 CFR 1926.1050 through 1060. Make sure you have a ladder that has the correct capacity, is in good repair, and is installed correctly. This of course would include the correct angle of installation and ladder extension above the deck.

An employer has to have to have its Competent Person evaluate each situation, and when the situation changes – which may be daily—re-evaluate to determine the feasibility of providing fall protection in compliance with the applicable OSHA standards. It is expected that this can be done no matter the circumstances unless proven otherwise; and proving a negative is almost impossible.

Tricks of the Shoring Trade

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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!

Where Did The Shoring Go?

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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.