Custom Crossover Bridge

This past year we were called out to a company who had some sprawling equipment. Because of the space required, their employees would be working on the second floor of the left hand mezzanine, and would have to climb down two flights of stairs, cross the forklift aisle, and climb up two more flights of stairs to access the left mezzanine to continue their work. As you can imagine, that was a huge inefficiency.

A-Mezz Crossover Platform loaded for delivery to install location

A-Mezz Crossover Bridge loaded for delivery to install location

We designed, fabricated, and installed a crossover bridge to allow them to quickly go from one machine to the next without requiring four flights of stairs to be climbed each time, and it also kept them out of the aisleway between the structures. Due to the elevation change between the two structures, we incorporated a stair at the left hand side of the bridge and fabricated the bridge stringers as one piece to allow it to safely reach each side without requiring any additional supports.

 

The left side was designed to mount on top of that mezzanine’s edge framing members and at the right we had to add additional steel to allow the crossover bridge to safely and securely attach to the side of the right hand mezzanine.

Installed A-Mezz Custom Crossover Platform

Installed A-Mezz Custom Crossover Bridge

 

Everything was painted to match their existing equipment. Ultimately, the customer liked the setup so much that they called us back a few months later to do another crossover just like the one we had completed for another location in their factory.  For more information on our custom fabrications please visit our website, email or call. 

Catwalk Bridges Can Save Space and Improve Efficiency

Recently we’ve been out to a local shop for a lot of projects. This time we were called to supply some catwalk bridges. This helps them better utilize their existing space by gaining extra storage and workstation space from the areas they already had. They have several buildings in their facility that were capable of housing light storage on top of them. Ordinarily, the easiest way to access these spaces is through a pre-engineered steel staircase. The problem you run into when you have many buildings in relatively close vicinity to each other is that floor space is a premium; you can’t afford to block off aisle ways with stairs, and even if you have the space to accommodate multiple stairs to access multiple buildings, it is not very efficient having to run up and down stairs from one structure to go to another.

One stair was put in place to access a central building and then a couple of catwalk bridges were fabricated and installed to access the ancillary modular buildings. The catwalk bridges were fabricated so they could be lifted into place with a forklift truck. This allowed for quick, easy installation. This also allowed the customer to remove them relatively quickly should they need the additional vertical clearance to bring larger machinery through their aisles.

Catwalk bridges between block wall and modular building

Catwalk bridges between block wall and modular building

Attachment to their existing cinder block structure was easy, but mounting to their modular buildings required some extra consideration. Modular buildings are weakest at the panel locations. We supplied angle so the customer could span the angle from multiple posts on the building and then fasten the bridge to the angle. This distributed the load of the bridges across two sturdy posts per side instead of hitting a potentially crushable panel.  The catwalk bridges were not going to be centered directly over their panels so the angle was sent extra-long to allow flexibility in their bridge locations.

The customer now has access to multiple interior building tops for additional workspace and storage, and hasn’t sacrificed much room on their floor now that they utilized crossover bridges to open up their previously unusable  spaces.

Installation of the Mezzanine’s IBC Stairs

 

Finished L-shaped external IBC stair

Installed external IBC staircase

Previously, I had written a blog post briefly discussing how to put one of our mezzanines together. It had a lot of good photos taken during the installation, so I was able to go through section by section what was done.  There was one particular area I didn’t get to to over in much detail though; the stairs.  While with the previous system that I wrote about, the customer designed and fabricated their own staircase, I recently received a fantastic series of photos from the installation of another system; this time with partially installed stairs included.

installing the IBC stair

Setting up the stairs

The IBC stairs for or mezzanine systems ship in knock down form and need to be installed in the field.  When installing them, you’ll want to lay the stringers on the floor about 3’ apart with the closed face of the stringers inward.  The diamond tread stair treads consist of a closed back riser and stair tread weldment.  Starting with the top tread and riser, you’ll need to bolt the the tread to the stringer fastening it on the inside of the tread.  Only hand tighten the bolts at this time, then work your way down positioning the riser of the next tread behind the flat weldment of the nose on the tread above.  After all the treads have been attached to the stringers (hand snug) you’ll need to install the bottom riser using self tapping screws.  You’ll then need to hoist the stairs up to the mezzanine deck.  Making sure that the dimension from the top of the deck to the top tread is equal to the dimension between the other treads, you’ll need to field drill the the attachment holes using a 9/16” drill and attach it to the mezzanine system.  You’ll also need to install the top tread plate on top of the mezzanine deck closing off the riser from your first tread.  From the underside, you’ll need to tighten up all the bolts and attach the risers to the back of the above tread’s nose via a couple self tapping screws.  Afterwards you’ll need to anchor the stairs to the ground.

 

Now all that’s left is to finish off the handrail.  The hoops that form the 21” and 36” handrails and handrail extensions come already welded to the stringers.  On each of the uprights, you’ll need to attach an elbow assembly via self tapping screws.  This will provide you with the saddles to support the outer 42” handrail.  You’ll need to take a piece of guardrail pipe for each side, and lay them flush against the saddles, fixing them in place with self tapping screws once again.  As the top line of rail will be longer than the stair run, you’ll want to drop a plumb line from the bottom edge of the rail to the edge of the mezzanine deck and again to the front edge of the bottom stair tread, cutting the pipe square.  Finally, you’ll need to install a plastic plug cap in the openings of the top rail to finish it off.  

Mezzanine Supported Modular Office

Mezzanine with modular office above

Mezzanine supported modular office with a two-wall modular building below

Whether you’re running out of room on the plant floor or need to oversee production, mezzanines are commonly employed to support and elevate modular buildings.  Recently we received some great photos back on a project we completed last month for a mezzanine supported modular office that I thought you might like to see.  The customer was located right here in Northeast Ohio.  They were putting in a new line on the plant floor and needed to tear down some offices they had in order to make room.   There wasn’t enough space to relocate the offices elsewhere on the plant floor, so they decided to utilize some of their unused overhead space.

Side view of mezzanine and modular office.

A 9’ high mezzanine supported modular office with an 8’ high modular wall system below.

When thinking on putting in a mezzanine supported modular building, it’s important to consider just how much space is available.  Remember that with typical column spans in low seismic areas, you’ll probably lose 1’3” to 1’5” for the mezzanine itself.  If you plan on having people move through the area you will need to maintain a minimum of 7’ for clearance.  The modular building panels are typically 8’ or 9’ tall, and unless you are planning on supporting them by the structure above, you will probably want about a foot more in order to install the roof deck to the panels which helps form the membrane that holds the system together.   In this particular case the customer’s mezzanine had a clearance height of 8’7” with a 9’10” top of deck.  This provided us enough room to install a modular office above (9’ tall panels, 9’3-1/8” overall height, 8’6” clearance height) and an 8’ high (8’3-1/8” overall with a 7’6” clear ceiling height) modular wall system below.

inside modular building

Four wall modular office above the mezzanine with customer provided/ installed floor covering

While designing these mezzanine supported modular offices, we’re often asked if we can utilize the adjacent existing walls.  While this is commonly done on the main floor of a facility, unfortunately we cannot do this up on top of the mezzanine deck.   There will always be some movement and vibrations on top of an elevated structure and because of this the structure would need to be a four wall system and not tie into the adjacent walls.  In this particular care, we put in a four wall system above the mezzanine deck as well as a two wall system below the deck to create an enclosed pass way between the production floor, the front offices beyond the cinder block wall, and the production floor entrance way to the outside.

inside view of two wall modular wall system

Two wall modular wall system below the mezzanine

It took our installers 6 work days to unload and install (both mechanical and electrical) the 24’x10’ mezzanine, the 24’x10’ 4-wall modular office above, and the 9’x22’9” two wall modular wall system below, and we had yet another very happy customer.

Visiting an Old Mezzanine Supported Modular Office

mezzainine supported modular office from 1997

After almost 20 years of service this modular office is holding up great

Occasionally, I’m asked about how well our modular offices hold up over the years if they are designed so that they can be reconfigured in the future as your needs change.  Surely, after general wear and tear they will want to just order a new building anyway, no?   Well, I recently had the opportunity to visit an old customer of ours.  Over the years, we’ve provided them with a number of mezzanines, catwalks, and modular offices.  Several of the modular offices have been disassembled, modified, and reinstalled in different locations.  While there, I got an opportunity to look at this old tank platform mezzanine and A-wall 300 modular office we provided them with back in 1997.  The steel decking has started to bend up a little at the seam in a couple areas, but after almost twenty years of service the mezzanine and modular office were in excellent condition.  If the customer wanted to, it would still be a simple task to disassemble the modular office and put it up again in a new location, possibly with a few modifications.  The components are all still compatible with what we provide today.  The only design change is that the I-splines used to connect the panels in the A-wall 300 modular building system are now typically painted to match the panels as opposed to the same color as the framing on the windows and doors.  So yes, these modular buildings are built to last.

 

Minimizing the Thickness of a Mezzanine Deck

W16x31 primary framing member with 4”x14” long tab side mounted to the column

A mezzanine deck thickness between the bottom of the primary framing member and the top of deck.

 

There are many times when the thickness of a mezzanine needs to be minimized due to various height restrictions.  The tightest we could normally provide a storage mezzanine would be one foot between the clearance height underneath and the top of deck.  In order to do this though, there are several things we need to consider.

First, we need to consider where the mezzanine is going.  Mezzanines in highly seismic regions, such as the Pacific coast, typically require larger and heavier beams than those installed in regions with minimal seismic activity, such as here in northeastern Ohio.  This doesn’t necessarily mean that we won’t be able to get the deck thickness down to a foot, but it does make it more difficult.

Next, we’ll want to look at our general design and column layout.  The positioning of the columns can greatly affect the size of the beams required and, in turn, the thickness of the mezzanine.  What are the required column spans for the project?  Typically we like to keep our column spans under 20 feet on center for economic concerns.  Longer spans require bigger beams.  Often if we’re trying to minimize the deck thickness we might need to go with even shorter spans.  We’ll also want to avoid a cantilevered deck if possible, as that too can require a larger beam than normal.

Another thing to consider is bracing on the deck.  Generally we have a moment connection between the columns and our framing members by trimming back the wide flange I-beam and bolting it directly to the side of the column without requiring knee bracing.  While trying to minimize the thickness of the mezzanine, we might ask you if we can use “tabs”.  These are typically 14” long by 4” high pieces of angle that we attach below the primary framing members at the columns.  This is particularly important when trying to keep the thickness of the mezzanine to just a foot, as there just isn’t enough beam to make a good solid connection.  We might be able to provide a mezzanine with 7’ clear and an 8’ top of deck, but at the columns above the baseplates you’ll have a piece of angle coming 4” off of that 7’.

The final thing to consider is price.  Minimizing the thickness of the mezzanine will increase the price.  The beams might be smaller, but they are heavier.  We might need to use more columns than usual.  We might have to replace all “C” section secondary framing members with structural steel beams.  All this extra steel adds to the cost.  On average, most of the mezzanines we provide have a deck thickness of 1’3” or 1’5”.  If the extra couple inches are critical then by all means go for it, but if not, it is usually not worth the added cost.

Mezzanine Deck Surfaces: Roof Deck with Steel Plate

Let’s continue on with our discussion on the advantages and disadvantages of the various types of deck surfaces we offer on our mezzanines.  First we talked about corrugated roof deck with resindek.  We mentioned that it was an extremely versatile and cost effective solid deck type, but that as a wood composite material it doesn’t perform well in environments where it is prone to getting wet.  Next we talked about open bar grating:  an open steel deck surface that excels in outdoor/wash down environments as it allows water, snow, and debris to fall through.  While texture in the bar grating provides a very grippy surface, it makes it very difficult to move pallets across and there are times when you don’t want materials to fall through the deck.  Today we’re going to talk about a mezzanine deck surface that combines features of both of these — corrugated roof deck with steel plate.

Like roof deck and resindek, roof deck with steel plate is a solid deck surface composed of two layers.  The strength of the deck comes from the corrugated roof deck.  The steel plate is there to provide a flat surface to walk across.  Typically we use a smooth plate which allows for easy transport of pallets, carts and other rolling materials.  Every once in a while though, where this is not the plan, we’ll go with a steel plate that has a raised texture to it, providing a better grip.  It’s a very strong and durable deck surface, and being a steel deck, it holds up in potentially wet environments.  In particularly wet environments you’ll want to seam weld the deck and set up a drainage system so the water doesn’t get trapped in the corrugation.

The biggest disadvantage of roof deck with steel plate is its cost, which is comparable to open bar grating.  Many of the applications that call for a closed deck mezzanine would be equitably serviced by resindek as it would by steel plate.  The resindek would have the advantage, though, as it is significantly less expensive.  Unless it’s in a potentially wet environment or being installed in a location where no wood is allowed, you might as well save your money and go with the resindek.

Mezzanine Deck Types: Open Bar Grating

Painted 19W4 open bar grating on an observation catwalk

Open bar grating deck surface on an observation platform.

 

Let’s continue our exploration into the different types of decking used on our mezzanines.  Last time we talked about corrugated roof deck with resindek.  We mentioned that as a wood composite material it can swell if soaked, so it is not the ideal deck type for wet environments.  Today we’re going to talk about one deck type that excels in wet environments:  open bar grating.

The typical grating that we use is a 19W4 bar grating.   It’s made by taking steel bearing bars placed 1-3/16” on center and joining them together by welding wire rod cross beams perpendicular to the bearing bars every 4” creating an open grid.  The grating typically has either a painted or galvanized finish depending on the application.

Galvanized serrated 19W4 open bar grating on a mezzanine deck

Serrated and galvanized open bar grating on a landing bound for the outdoors.

 

Galvanized and serrated open bar grating is an ideal deck solution for outdoor applications.Open bar grating has many advantages as a decking material.  It is very strong and durable, and the grated surface provides excellent traction.  For particularly slick locations, such as oil factories or outdoors in icy environments, we offer a serrated version for even better grip.  As an open decking surface it easily allows water, air, and light to pass through the system.  This is why it is a particularly popular decking material for outdoor applications.

There is one common misconception about the open bar grating that I would like to note though.  We are often asked to put open bar grating in sprinkled environments, with the customer thinking that they will not need to add sprinkler lines below the platform.  Unfortunately this is not the case.  The decking and framing of the mezzanine system occlude the area below enough (even before factoring in the materials on top of the platform) that your fire inspector will still require you to sprinkle below the deck if it is sprinkled above.

Oddly enough, open bar grating’s strengths are also its weaknesses.  As a fabricated steel material, it is significantly more expensive than the resindek.  The grated surface makes it extremely difficult to roll pallets and such around on top without adding something like a layer of plywood in order to provide it with a smooth surface to roll across.  And as an open, porous material it allows things to flow through it, such as fingers, heels, dropped hardware (i.e. nuts, bolts, screws), or spilled material.

Outdoor Stairs for a Construction Trailer

How to get safe permanent access to a construction trailer

Wooden construction trailer stairs

Temporary wooden construction trailer stairs

Job site construction trailers are used all over. Some are temporarily placed in location and then relocated, and some are permanently stationed. The construction trailers can house offices, tools, machinery, electrical controls and more. Oftentimes, job site trailers will have temporary wooden stairs affixed, like the above photo. But what do you do when the construction trailer is actually in a permanent or semi-permanent location?

assembled metal stairs for construction trailer

Shop assembled job site stairs

We often get calls to fabricate replacement construction trailer stairs to replace temporary wooden steps. The stairs below were used with job site trailer that housed electrical control modules and needed a safe OSHA compliant means of access from two sides.

removable handrail on metal stairs

Close-up of removable handrail option

As the construction trailer had some large control modules inside, we supplied stair landings with handrails that can be unbolted, to allow ample access should any module need to be replaced. The stair railings were welded to the stair stringer to maintain a stiff, wobble-free grabbing surface.   In an effort to help keep costs down on the project, the stairs were supplied with two support columns instead of four. This was achieved by bolting the platform edge of the landing to the existing structure, allowing for less steel to be used and a smaller concrete pad to be poured.

stair landing with grating for snow

Bar grating decking allows dirt and snow to fall through – allowing for a safe, clear walking surface

Construction trailers are generally located outside in work zones, oftentimes lacking paved access to the doors. With that in mind, the stair treads and stair landing surfaces are most commonly constructed from bar grating. Bar grating is inherently self-cleaning; mud, dirt, rain and snow fall through the treads keeping them cleaner and safer to step on. The landing also has toe kick around the non-entry and exit locations. The 4” high toe guard stops tools and other items from being kicked off the landing. It also serves to stop a slipping foot from falling off the landing, potentially preventing a serious injury and employee downtime.

fully assembled construction trailer stair with galvanized finish for corrosion  protection

Construction trailer stair with a galvanized finish for superior corrosion resistance

As for finish, hot dipped galvanized is one of the best, cost effective finishes to use when the stairs will be exposed to the elements. No chipping, peeling or blistering of the coating will happen. In fact, when the hot dipped galvanized surface is scraped to bare steel, it will ‘self-heal’. The zinc rich galvanized surfaces to the sides of the bare metal will sacrifice themselves to protect the base steel until all of the surrounding zinc is consumed. Hot dipped galvanizing also coats 100% of the structure because it is immersed in the zinc solution, as opposed to being painted on, which can miss hard to reach areas.

Overview of the prefabricated mezzanine installation

By Derick

Front topside view of the completed parts storage mezzanine

Front topside view of the completed parts storage mezzanine

We’re often asked by customers if they’re able to install their mezzanine order on their own. The following series of pictures were sent to us from a customer who did just that, and should provide you with a general idea of what a mezzanine installation entails.

First, a little bit about the mezzanine. The customer was a metal welding and fabrication shop in Iowa and they were looking to move their parts storage up above the production floor. They wanted to provide their own staircase, but contacted us to design and provide them with a 46’ x 24’ mezzanine. Because this was going above their production area, they wanted to maintain at least a 10’ clearance height and to minimize the number of columns below the mezzanine deck. The mezzanine clear spanned the 24’ and broke the 46’ span into two 23’ nominal bays using a beam and c-section framing system. This left the customer plenty of space to maneuver around and work below. The deck was designed to accommodate both the point loads from their single rows of shelving as well as 125 psf distributed live load to accommodate 4’x4’ pallets up to 2000 pounds each.   With the mezzanine situated in the corner of their building, we provided industrial use two rail handrail with a 4” kick plate on the two exposed sides, as well as along the opening for the customer’s staircase per IBC code. The decking on the other two sides was extended beyond the framing to the existing walls in order to utilize deck space and eliminate the need for additional handrails. The customer added additional resindek to their girders in order to further close off the walls and protect their insulation.

Attaching the primary framing members to the columns

Attaching the primary framing members to the columns

Now for the installation of a prefabricated mezzanine, we would recommend a three man crew. You will want a fork lift on hand, and a scissor lift if possible. As everything is typically bolted together or fastened with a self-tapping screw, there is very little in the way of specialized equipment required.

Starting in the back corner and working forward, you’ll begin by positioning your columns and bolting in the primary framing members. Use the forklift to position the beams and hold them in place while you connect them as the beams can be quite heavy. A spud bar will come in handy to align your bolt holes. You will need to reach inside the square tube columns to tighten the bolts.

Connecting the secondary framing members

Connecting the secondary framing members

After the primary framing members have all been attached, your next task is to bolt the secondary framing members to the primary framing members. After all the framing is connected and tightened down, it’s time to anchor the columns to your floor with the provided concrete wedge anchors.

 

Installing the corrugated roof deck on the mezzanine

Installing the corrugated roof deck on the mezzanine

Next you will install the kick plate and decking to your platform. In this example we used a corrugated roof deck for the structural component and covered it with resindek. This was done to provide the customer with a cost effective and smooth surface to work on. The kick plate is an angle that goes between the roof deck and your primary framing members. This closes off the platform so you cannot see down the corrugation of the roof deck from the sides. It also protects workers below the structure from material/tools, etc. that could roll or be kicked off the top level. The roof deck sub floor is fastened down to the framing members below using the provided self-tapping screws at every valley. You’ll then need to install the deck surface and secure it to the sub floor. The tek screws for the resindek are provided in a ribbon for use with a stand-up screw gun in order to speed up the installation process, as each 4’x8’ sheet of resindek takes 20 screws to properly fasten.

Installed unfinished resindek on the completed parts storage mezzanine

Installed unfinished resindek on the completed parts storage mezzanine

We’re almost finished now. Our railing is typically mounted on the face of the mezzanine with a post that will need to be bolted on every eight feet at maximum. The railing typically ships in 21’ long pipes that are cut in the field to the appropriate lengths. The cut handrails are then connected together with the provided splices and pipe elbows, and are fastened to the saddle brackets of the posts. You will need to install the splice clips for the kick plate at every seam to establish a continuous appearance.

Underside of beam and c-section mezzanine with surface mounted lighting attached to the roof deck

Underside of beam and c-section mezzanine with surface mounted lighting attached to the roof deck

Generally you would still need to bolt the treads to the stringers and finish off the handrail for the staircase, but in this case the customer was going to fabricate their own stair.

While this has been just a general overview, your mezzanine would ship with a very detailed set of assembly drawings and instructions that would go into much greater detail on the installation. This customer was pleased with the ease everything went together and the quality of the platform.