Coil Lifting Systems Webinar-Coil Lifting Systems Webinar Presentation

Coil Lifting Systems Webinar Presentation

Video Transcription

Good morning, welcome to PCI's webinar series. My name is Royce Covington, Manager of Member Services at PCI, and I'll be your moderator for this session.  Before I turn the controls over to your presenter today, I have a few introductory items to note.  Earlier today, we sent an email to all registered attendees with handouts. The email contained handouts of a PDF of today's presentation, a webinar attendance sign-in  sheet, and a guide to downloading your Certificate of Continuing Education. The handouts are also available now and can be found in the handout section of your webinar pane.  If there are multiple listeners at your location, please circulate the attendance sign-in sheet and send the completed sheet back to PCI per the instructions on the form.  The attendance sheet is only for use at locations with multiple listeners. If you're the only person at your location, there's no need to complete an attendance  sheet, as we already have your information. With hundreds of attendees for our webinars, it's impractical to prepare individual certificates.  You will upload attendance data to www.rcep.net within 10 days, and you can print your Certificates of Continuing Education.  Your login name at www.rcep.net is your email address, so please do not leave that blank if you're completing the sign-in sheet.  We need your email address to get you your certificate for this course. If you do not have the course handouts or can't download them, please email PCI Marketing  at marketing at pci.org as shown on your screen. In addition to copies of the handouts, your webinar pane has an area for you to raise your hand.  If you raise your hand, you will receive a private chat message from me. If you have a question, type it into the questions pane, and I'll be keeping track so I can read  them during the Q&A period. PCI has met the requirements of the AIA Continuing Education System and can offer one PDH for this presentation.  We are a registered provider of AIA CES, but this presentation does not contain content that is endorsed by AIA.  Any question about the content of this webinar should be directed to PCI.  Today's presenter is Carl L. Harris, CFA, founder and president of Carl Harris Company Incorporated, a specialty contracting firm engaged in the erection of structural steel  and precast concrete in Kansas and neighboring states. Mr. Harris is a certified field auditor, certified company auditor, and PCI lead auditor for the Certified Erector Program.  Carl has been active with PCI since 1999 and was instrumental in helping implement the initial Erector Certification Program.  He serves as chair of the Certified Erector Committee and co-chair of the Erector Committee.  He also serves on the Tolerance Committee, Erector Safety Task Group, and Supplier Safety Task Group.  And for his outstanding contributions to the industry, Carl was awarded as a PCI Fellow in 2016.  Additionally, he is an OSHA authorized trainer for the OSHA Satellite Training Facility in Wichita.  Today's presentation will be recorded and uploaded within the next week to PCI's website. Now I'll turn the controls over to our presenter so that we can begin.  Boys, can you see my screen? Yes, I can. Excellent. Welcome, everybody, to PCI's Coil Lifting System webinar.  This webinar was created and presented by the Quality Activities Supplier Committee of PCI.  The purpose of this webinar is to inform precasters and erectors of potential safety issues given the absence of a national standard for the production of coil bolts and inserts.  The assurance of a complete fit and an efficient lift connection cannot be guaranteed without that standard.  The concern arises from different suppliers and or manufacturers or fabricators of these connection pieces, the rods, the bolts, and the inserts, which use different specifications.  Those concerns stem from major and minor diameter of the rods and bolts and the thread pitch, including other tolerances.  Further concern stems from the repetitive use of component elements, which require individual inspection of each element prior to use.  To assure a safe lift, we need to make sure that we look at these components, and so now we're going to look at the components that make up a coil lifting system, the insert,  the coil bolt, and the bale or lifting device. All play an integral part in the lift and should be inspected.  Here are some examples of the coil insert types cast into precast units to be used for lifting.  As shown on the slide, there are different types of wire configuration, but the common aspect is the central coil.  These examples show two-strut and four-strut insert types, which refer to the number of struts welded to the coil.  Prior to the placement, each of these inserts should be inspected to make sure that there are no broken welds connecting the struts to the coil. Here are two examples of coil nuts.  The use of standard nuts, the shorter nut on the left, will not deliver a full strength of the coil rod being used.  The heavy-duty nut, the one on the right, or the use of two standard nuts together, also referred to as double-nutting, increase the safety factor and will develop the full  strength of the coil rod. This slide shows coil rods and bolts, and they come in various diameters and lengths. Some manufacturers make bolts by welding nuts to rods.  These figures show two types of coil-bolt swivel bales. The one on the left is a single-swivel bale and must only be used when the load is applied in a 180-degree or less range.  The double-swivel bale on the right can be used when the load is applied in multiple directions, allowing the bale to swivel.  With the double bale, as the load is applied, the bale swivels to the 180-degree lift position. Always remember to use the proper bolt size for the bale being used.  These pictures show the use of the single and double-swivel bales in use. The single swivel on the left and the double swivel on the right, allowing the handle of  the bale to swivel in line with the crane line as the load is applied.  This slide shows an example of a manufactured lifting angle using two coil bolts and a shackle to create a bale or lifting device.  Please note that the stiffener plate that holds the shackle only allows the shackle to rotate 90 degrees and is not reinforced to be used in a sideload application.  It is important to note that the shackle is not to be sideloaded, therefore no sling angle in that direction is permitted, as shown here in the red arrows.  Some manufacturers also make lifting loops to be used with inserts in precast. When using these loops, care should be taken to keep the lifting loops in vertical tension  only, absolutely no sideloading. The threaded cable lifter or loop must not be used to rotate panels.  You should also note any manufacturer's specifications for the degrees from vertical allowed for lifting as well as the various capacities and other limitations placed there by the  manufacturer. So we said that there was no national standard in regard to coils or inserts. So because of that, each manufacturer may have variations of thread pitch, wire diameter,  grade, coil length, and the number of turns that are going to vary between manufacturers. And there could be other differences that make it imperative that we only use matching  components in the lift. We should inspect all coil bolts and inserts prior to the use or installation.  As for bolts which may be repetitively used, these should be inspected before each use. Other lifting hardware, the bales, loops, shackles, and rigging should also be inspected  before each use as they're part of the lift. Now let's turn our attention to the coil insert itself and its proper use and placement.  The key to developing the engineered capacity of the lift is the bolt's proper engagement into the insert per the manufacturer's recommendation.  Proper placement of the coil prior to the precast pour is critical as part of this. If we look at the slide, we can see how the manufacturer is asking for the placement to  be made in the concrete. When the coil inserts are used for lifting, it's highly recommended that only four strut  inserts be used with a minimum insert diameter of three-quarters of an inch. Two strut inserts do not have the shear capacity for the lifting and may only be used if the  lift is in a straight line with the insert. It is always good practice to just use the four strut inserts in all scenarios for lifting when using this coil bolt system.  Proper bolt engagement involves proper bolt length and insert placement. To determine the minimum bolt length required, the bolt must penetrate the swivel plate,  the insert recess, the coil, and extend beyond the coil one-and-a-half bolt diameters as shown in the slide.  To determine the maximum bolt length one could use, you need to add the swivel plate thickness,  the insert recess, and the void link together to add the absolute maximum for bolt penetration. Caution should always be taken when using a bolt of maximum length because the fear  of bottoming out can damage the precast and destroy the coil. Issues that can arise from improper bolt length can be catastrophic.  If the bolt is too long, it can bottom out and can damage the precast or weaken the insert capacity by damaging the precast around the insert and breaking the welds of the insert.  If the bolt is too short, it will only engage in some of the coils, which could become and begin to unravel or pigtail, as some call it. Both scenarios can lead to lift or failure.  I've talked a great deal about inspection, so let's take a look at the inspection methods to be used to examine coil bolts and inserts to determine proper size.  Some manufacturers have developed inspection tools to examine their products to ensure proper fit of their coil bolts and inserts.  The following slides will describe each tool and their use. This is an example of a proprietary go-no-go gauge used to determine the appropriate inner diameter.  The left photo shows proper fit using the tool, and the right photo shows improper fit. Again, another example, this is an example of a proprietary go-no-go gauge to determine  the appropriate inner diameter also. The left photo shows proper fit, and the right photo shows improper fit.  The picture on the right shows a no-go condition where the gauge is being pulled all the way through without engagement.  If you have access to these proprietary inspection tools, make sure that you're properly trained on how to use them.  This is also another example of a manufacturer's proprietary pitch gauge. Again, we want to check the thread pitch of the coil insert to make sure that it was manufactured  properly and will fit the rod. Again, the left photo shows proper pitch, and the right, an improper pitch.  When the fabricator or supplier gauges are not available, calipers can be used to check conformance.  You need to consult the supplier and fabricator for the proper procedure and how to measure to determine the proper pitch. This method is not as accurate as the proprietary gauges.  Some manufacturers have also developed gauges for checking the diameters of coil rods and bolts. The left photo shows proper diameter, and the right, improper.  Again, the left, we're looking at major outside diameter to the maximum, and it is good, and the right shows that it is not appropriate.  Again, the same no-go gauge checking out the outside diameter minimum to be checked using a proprietary gauge.  One of the simple methods to be checking whether or not a coil nut matches a thread pitch would be to use a nut.  If the nut runs down with ease without excess movement, the left photo, you have proper pitch.  If it doesn't, the right photo shows improper pitch, and the nut does not go on easily. Like the coil insert pitch check, calipers can be used to check coil rods and bolts for  their pitch given the manufacturer's parameters, so you would still need direction from the manufacturer to check the pitch. Recognizing other conditions may exist.  Please be aware that this type of the type of precast that you're erecting. Also be aware of weather conditions that require the protection of the components from  debris, such as ice or sand or dirt that get down into the coil insert to make sure that there's proper fit and engagement. Also note the component design and rigging.  Other state and federal compliance issues should also be considered. The requirements for tilt-up may be extremely different from the precast requirements when  considering coil insert use. You should always refer to the manufacturer's guidelines and their design requirements before lifting. We appreciate you attending this webinar.  It is our goal that you can use this in your plant, in the field, and in your considerations for design.  We would hope that you've garnered some good and useful information from this. Are there any questions?  Well, Carl, we have quite a few questions, actually, and I'll get to the first one. It says, why is there no standard on this important product?  Like national course or fine course threads, I think that there has never been the recognition for the need for this until now.  The Quality Supplier Committee had come up with this concept as a driver to raise awareness for the need for a national standard, like national course or fine thread.  We don't know why there hasn't been, but we recognize the need, and so PCI is going to be asking for that kind of discussion, but until then, we need to work with the products  that we have and making sure that the coil bolts and inserts are matched before the lift. Excellent.  All right, our second question is a two-part question. It says, with aircraft cable, you said it must be absolutely vertical lift. Is this realistic?  What is wrong with a 10-degree angle or a 20-degree angle? Now I wasn't referring to aircraft cable. I was referring to the loops that make up the loop insert.  So the loop insert lifting device, you should always work with the manufacturer's recommendation because once they start going some degree left or right or otherwise, we don't know  how the strands are developed. So again, caution should be had, and that's why we had on the slide, make sure that you  deal with the manufacturer when dealing with those coil loops or those that use the aircraft cable. Okay.  Next question, why does the bolt need to be 1.5 bolt diameters longer than the coil? What would be the failure mechanism if shorter?  Again, that's a manufacturer's requirement to make sure that there is full thread engagement of the insert.  If other manufacturers require less of a protrusion through the bottom of the coil insert, then that could be appropriate.  That is just the standard from the manufacturers that we receive the information from. All right.  Next question, in the two lead inserts, do you need to put a perpendicular bar inside? Could I hear the question again?  It says, in the two LED inserts, do we need – lead inserts, do we need to put a perpendicular bar inside? I don't understand the question.  Whoever wrote that, if you could clarify the question either to a slide. I'm not understanding that question. Okay. We're going to move on. Here's the next question.  What about yield strength, lifting capacity, and MTC? The yield strength? Was that the question again, please? Yes. It was, what about yield strength, lifting capacity, and MTC?  All of those would be part of the manufacturer's recommendation as to the use of the insert. I think that that's just got to be developed by the designer of the product, and all of  those are the different tolerances made by each manufacturer. The challenge comes because the erector only knows that it's supposed to be a three-quarter bolt.  There's a three-quarter insert. The rest is in the design. I'm hoping I answered that correctly or got to the meat of the question. All right.  We're going to move on to the next question. Can coil inserts be used to carry permanent loads and structures, not just for lifting and handling?  So coil bolt inserts are used for other items other than lifting.  The big concern that we were trying to address in this webinar has been for the lifting, because we're worried more about pullout as the loads are exerted on this.  Coil bolts are used for a lot of things, for tying in pore slabs, for edge angles, stuff like that, when a great deal of the information or the great deal of the need is for shear  or other. So, yes, coil bolts can be used in other applications other than lifting, but you need to make  sure that you're talking with the manufacturer as for the proper use of the coil insert other than for lifting.  Okay. All right. Do the struts and the coil and the bolt have to be of the same strength? Again, when we talked about they need to be compatible so that the strength of the members  involved that, as we talked about in using a standard nut or a bolt and a heavy-duty nut or double nut on the bolt itself, you'll find that the coil bolt has a great deal of  strength, and so it may have more strength than the insert. So we need to make sure that they're compatible, and you need to make sure that the manufacturer's  recommendations are adhered to for the capacity of the insert, because the insert may develop greater capacity by the number of turns in each loop and the number of struts that make  up the coil insert for thread engagement.  Excellent. The next question is, are there any recommendations for patching of the setback after the installation is complete?  So, yeah, the reason why the insert is recessed into the panel that we have that recess at the beginning is to allow for the coverage of the insert.  So again, the manufacturer's recommendation as to how far from the face, not the face, but the back side of the panel to the insert be adhered to so patching would be appropriate.  Okay, thank you, sir. The next question is, coil anchors often use a plastic screw-on cone to install coil anchors, but have closer to a one-and-a-half-inch setback.  How does that affect shear strength of coil anchors? Well, it can affect it, and so the design of the lift.  So you need to make sure that the lifting device that you're using is appropriate to go over the void there.  The greater the inset is from the face of the panel, the greater chance of a bending action to occur in the coil bolt itself.  And so that's why it's very important that we inspect each coil bolt after each lift because fissures or cracks can occur when bolts aren't tight or that cone shape or the  amount of void in there can allow the bolt to bend a little as it goes to vertical. But again, only if the panel is being tripped in that position, it would be less of a concern  if the panel was going up vertical from its vertical position from the lift. But it could occur when the panel is being tripped from horizontal to vertical. Okay.  Next question is, what is more durable and safe, a double-nut or a heavy-duty single-nut? It would depend on the requirement of the lift.  As we said on the slide, it takes a double-nut to have the full strength of the coil rod. But the coil rods can be very strong, so you may not need that.  A headed bolt or a factory bolt may be sufficient, so you're going to have to make that determination for the strength needed.  A double-nut would be like Belden suspenders, but again, you have to go back to what the lift requirement is going to be. Okay.  Our next question is, when tripping or rotating a wall panel with edge lifters on the top of the panel and face lifters on the bottom of the panel, is there a pair of coil lifting  devices and swivel plates that can be used on the face of a 30,000-pound precast wall panel to trip or rotate the panel? I'm certain there is.  Coil bolts and inserts come in various sizes. The weight of the panel is one part of it, but it's also the thickness of the panel.  As the coil insert gets bigger, the deeper the insert is going to have to be. A better attachment may be some other kind of lifting device on the face.  We normally see coil bolts and coil bolt inserts used on lighter weight, more architectural than large-piece, heavier structural panels that might use some other kind of lifting  insert. Awesome.  Next question. During lifting of precast panels in a windy situation, are threaded inserts recommended or not, and why? In a what situation? I'm sorry. I didn't catch that.  In a windy, extremely windy situation? Windy. I'm not sure you're going to know the wind condition when you're designing the panel when the insert goes in.  I don't know that I could answer that, again, depending on the weight, the wind, because wind has a wind load applied to it, but it's probably going to be less in the tripping  situation than it's going to be in the actual hanging situation. Again, I don't know that I have a good answer for that. All right. Next question. Next question.  Does PCI – have you, while on a committee at PCI, worked with a table recommending specifications to check, including information such as pitch, minimum diameter, or major diameter?  Again, those are all manufactured. This came up to the committee, and the committee had at least three manufacturers on it that  have their own specifications as in regard to minimax, diameter, pitch, wire size, and so on.  Again, I think that there's a willingness to come up with a national standard, recognizing that there are costs involved for each of these manufacturers to retool or retool their  suppliers. In the meantime, we're trying to raise awareness of mixing and matching a bolt from one manufacturer  with the insert from another, recognizing that erectors may have a bucket of bolts from  all three manufacturers, and a precaster may have a bin of inserts from the three manufacturers, all of which may be used in a single panel.  We're trying to raise awareness that there are risks whenever that's being done. That's why we're trying to raise the awareness. Okay. Thank you, sir.  Next question is, are there any temporary plastic protectors to safeguard against debris getting into the coil assemblies? Absolutely.  There are several of those plastic protectors being used a great way because they also, during the pour, allow for concrete not to get down into the coil insert.  A lot of those plastic cap components are removed before delivery. A good option would be to pull the cap out and then to make sure that there is not excess  concrete in the bottom or that it was placed so that the coil insert allows the bolt to get its full protrusion and then have the plastic cap placed back in the coil.  Most of the time when the inserts are being used, and we're talking about lifting here, but a number of inserts are used for bracing this way.  A lot of those caps are left in because not all of the bracing inserts may be used. There's no need to take those out and then have to repatch over those insert holes.  There are good caps out there to be used, yes. Okay. Our next question is, how applicable are coil assemblies for seismic slide connections in  simply supported precast, prestressed units? I don't know that I'm prepared to answer that. Again, we're looking at these insert types to be used when lifting the product, not for  the permanent structure seismic conditions. I'm not prepared to answer that. I think the manufacturer might be able to have data to be able to answer that question. Excellent.  Next question, are the coil insert capacities different for plain concrete versus reinforced concrete?  Again, I would have to direct you to the manufacturer in regard to how they would recommend their  insert and the capacities being used in reinforced concrete, normal weight concrete, other mixed designs. Those would all be determined by the manufacturer of the insert. Okay.  The next question is, is it ever okay to make your own bolt by welding a nut to a length of all-thread?  As we stated earlier in the slide, some manufacturers, that is their preferred method for making bolts. Practice is that bolts like that get made all the time.  The key is that the nut and the coil rod be of appropriate matching sizes and pitch. The answer is, it could be appropriate because manufacturers do it all the time, or some  manufacturers do it all the time. Okay. Next question, what is the best way to keep snow and ice from getting into a coil insert after panel is cast?  Again, once it has gone through the process, we have seen a number of things. If somebody removes the cap that keeps the concrete out of the coil, if they can salvage  that piece so it can go back in, another good way that we have seen used in our market is  the placement of backer rod, the same backer rod that is used between panels prior to caulking.  That kind of foam can be placed in there to keep dirt, debris, and ice from formulating in the coil.  That is why it is so important that the components be compatible because if it was a little oversized  and there was debris in there, the coil bolt itself into the insert may feel like it is  a good fit, but it is only a good fit because there is debris that is making up the difference. That is why it is imperative that we match these components.  We have one more question. Is there an ASTM for manufacturing the coil rod, lifting bale, or nuts? I am not sure I know that answer because it is not a national standard.  It would have to do with – I do not know the answer to that. That would have to be a manufacturer's question.  It would have to be for the strength of the rod, but maybe not the shape, pitch, or diameter of the rod.  It looks like our next question asks, is there a rule of thumb for depth of coil assembly relative to depth of precast products? I am not sure.  Again, manufacturer's recommendation for the use of the insert should be adhered to. Each one of those manufacturers should have the insert made for the depth of the panel  or thickness of the panel. Our last question is, lute strand versus coil insert. What are the advantages and disadvantages of each of those comparisons?  I think the advantages may be capacity and patchability of the insert. Loops are used occasionally. We see that quite a bit in the backside of panels.  There is a reason why people prefer or do not prefer either one.  We have seen both used. I think it is the engineering that you need to look at. The coil insert allows you to have a really smooth and often trialed finish if you need  that on the backside that you really cannot get with a loop in the back, but we have seen all used. Loops allow things to be stripped up as well. Excellent.  Those are all the questions we have today. On behalf of PCI, I would like to thank Mr. Harris for the great presentation and all attendees for your participation.  As a reminder, a certificate of continuing education will appear at www.rcep.net within 10 days.  If there are multiple people at your location, please send the completed attendance sign-in sheet to Marketing at PCI.  A recording of today's webinar will be uploaded to PCI's website within the next week. If you have any further questions about today's webinar, please email Marketing at PCI.org  with the title Online Coil Webinar. Thank you again and have a great day.  Are you calling to fire me?

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