Engineer FAQ
Why are anchor rods (bolts) not supplied by the building manufacturer?
Anchor rods are embedded in the concrete and rely on the pier reinforcement to generate their strength. They are included in the concrete package just like rebar, tie rods and hairpins. Foundation engineers will determine the embedment length in their concrete designs.
Are anchor bolts and A307 bolts to be tightened in the same manner as A325 high-strength bolts?
No, only A325 bolts require turn-of-nut tightening. A307 bolts and anchor bolts are to be tightened to a snug condition.
How should suspended equipment be attached to the purlins?
Suspended equipment should be attached to the web of the purlin. This will allow the load to be properly transferred to the purlin without causing the purlin to roll, as is the case when large loads are suspended from the purlin leg or lip..
What is the minimum thread penetration required for high-strength bolts?
None. As defined in RCSC Commentary Section C2, full thread engagement is achieved when “…the end of the bolt is at least flush with the face of the nut.”
Can A325 high-strength bolts be reused?
A325 bolts (except if galvanized) shall be considered satisfactory for reuse, regardless of previous use, if the nuts can be placed on the threads and run down the full length of the thread by hand.
Do we really need to attach the flange braces at all the locations shown on the drawing, and what do we do if the owner requests one to be removed?
The flange braces must be installed per the construction drawings. If the owner requests any modifications to these drawings, this request should be forwarded to your Customer Service Manager for review by Ceco Engineering.
How can I tell the difference between a steel building system and a conventional building?
In many cases this is not possible from the exterior. A large percentage of conventional structures are supplied as metal building systems.
Is a steel building system a good choice when an architectural influence is required?
Yes. Steel building systems are widely used for churches, car dealerships and sporting arenas where a defined architectural appeal is required. Each project is custom-designed to meet the architect’s vision.
Does using a pre-engineered steel building limit me to a basic, rectangular-shaped structure?
Not at all. Our in-house design and drafting software gives us the flexibility to engineer very complex structures, including hip/valley roofs, skewed walls and even hexagonal or octagonal shapes. In fact, our long-standing motto is “Non-standard is standard!”
Why is the foundation design not included with the package?
Ceco does not perform foundation design as outlined in the Metal Building Manufacturers Associations Common Industry Practices section 3.2.2. However, Ceco provides in the building package the location, diameter and reactions required for each individual column to allow an Engineer to design a foundation that meets the specific soil and site conditions.
I’m committed to designing a "green" building. Will using a Ceco building allow me to do that?
Yes, it will. Steel construction offers recyclability and durability in and of itself. Our buildings can contain 30-50% of recycled material, depending on the project. Many of our “cool color” panel finish options meet the reflectivity and emissivity performance levels required by LEED and Energy Star. In addition, we offer insulated metal building panels that allow the designer to obtain superior R-values for greater thermal efficiency.
Does Ceco offer any hybrid or truss roof system design?
Ceco can offer both a hybrid design for a heavy load condition as well as our Long Bay® roof system. The hybrid design utilizes the efficiency of a metal building system with the strength of conventional steel members. This offers design flexibility and single-source responsibility. Our Long Bay® system allows for a truss style metal roof framing made from roll formed steel that takes advantage of the inherent benefits of a steel building system. The result is a lightweight, cost-effective roof structure for spanning bays generally 30-60’ between main frames.
I cannot have x-bracing in the side walls of my building. What can I do?
X-bracing is the most economical method of moving the eave force due to longitudinal wind from the eave to the foundation. If x-bracing cannot be used, there are other methods. Many times the x can be separated and put on one of the diagonals in adjacent bays or separated by one bay. If this option is not acceptable, alternative methods may be used, such as portal frames, cantilever wind columns or diagonal pipe struts, which act as both a tension and compression member. Sometimes the walls are open for other materials that can be used for bracing. Masonry walls or concrete tilt walls are good examples. The eave force must be transferred to the wall and the wall capable of resisting this longitudinal force. The designer of the wall must verify the adequacy of the wall to accept this force.
I am designing a warehouse building that has full height concrete tilt walls. Can I eliminate the steel sidewall columns and utilize the tilt wall as support?
Yes, this can happen, but the connection at the rafter to tilt wall will have to be designed and analyzed by the designer of the tilt wall. In addition the horizontal force at the top of the tilt wall will have to be transferred to the roof bracing by some method.
If the walls of a metal building are open for other materials, will the secondary framing members (girts and eave struts) support these walls?
These secondary wall support members (girts and eave struts) are designed to carry only the tributary area in their span (approximately three to five feet). Normally the other wall material has a span greater than that of the girt or eave strut which will require some method of transferring the force at the top of the wall to the sidewall or end wall columns. This is normally accomplished by a channel or beam depending on the magnitude of the load being transferred and the deflection requirements.
Why are metal building columns so deep compared to conventional steel framing?
The main reason is in the approach to the design and type of member used. Metal buildings utilize a rigid frame in lieu of a conventional column and rafter design. The rigid frame is a continuous design from base plate to base plate utilizing built up sections rather than prismatic hot roll shapes and place steel only where steel is needed to satisfy the design requirements. The member is shaped to follow the areas that need deeper sections due to the forces. Automated manufacturing plants allow the additional labor to be offset by the savings in steel thus producing a more economical frame.
I want to put cranes in my new steel building system. How can they be supported and what type cranes may I use?
A properly designed steel building system may be designed to allow for a crane system or multiple crane systems. A steel building can accommodate top running cranes, underhung cranes, monorails, gantry cranes, and jib cranes. Top running cranes may be bracket supported on the main columns, or have independent crane support columns braced to the main frames. Underhung cranes or monorails are bracket supported from the rafters. Jib cranes are bracket supported from the support columns with a brace to support the boom. All cranes need complete crane design information along with necessary clearances from the nearest obstruction and the exact location on the columns or rafters.
My new steel building has a mezzanine in a portion of the building. Is it better for the mezzanine to be independent of the steel building or a part of the steel building design?
Any time you can have an integrated design you have a structure that works as a unit. If the mezzanine and the building are designed as a unit they will act as a unit. An example would be in a seismic controlled design if the mezzanine is not designed to carry the seismic forces then the full horizontal impact of the mezzanine is transferred to the main frame to be resisted. It would be a more efficient design to resist the seismic forces in the mezzanine than in the rigid frame.
My customer relocated a walk door, now it interferes with the "X" bracing in the wall. Can I remove the bracing in that location?
No; X-bracing provides a critical function in the longitudinal stability of the building. If the bracing cannot be relocated to another bay, there are a number of alternative bracing methods available (e.g., portal frame, cantilever column, portal rafter, minor axis column bending, shear wall). Each unique situation needs to be addressed on a per job basis. Your engineering support team in the office will gladly assist you in choosing the best alternative method.
The specifications call for washers to be provided for the bolted connection. Why were washers not supplied?
Per the AISC, when turn-of-the-nut tightening is used, hardened washers are not required.
Why do you not provide Errors and Omission Insurance?
As a manufacturer of a product, we do not sell, render or perform any professional services to outside parties. Instead, we maintain Commercial General Liability insurance which includes Products Liability and Completed Operations coverage that triggers in the event of an occurrence resulting in property damage or bodily injury should a defect be discovered in one of our products.
What is the difference between "turn-of-the-nut" and "snug-tight" for method of tightening bolts?
Turn-of-the-nut is a method that provides a specific tension in the bolt. It requires an additional amount of nut rotation beyond snug tight. Snug-tight is the full effort of a man on a standard spud wrench. Snug-tight is allowed as long as the building has no cranes and the building is not located in a high seismic area. For these two conditions, turn-of-the-nut is required (see the AISC for further specifics on the turn-of-the-nut procedure).
The mechanical design came out late and I need to set an 800-pound unit on the roof. Is it OK just to set the roof top unit on the purlins?
No. Any loads in excess of 250 pounds may require additional framing in the roof and possible frame beef-up. Please contact the engineering support team in the office for advice.
How do I find out what building code and design load is required for my steel building system?
While some states have a very specific code adoption process, it is always good practice to contact the local building official and ask for the code and load requirements for the exact building site before proceeding with the order.
No Job Too Large or Small
From compact facilities like park restrooms to airplane hangars with clear spans over 200 feet wide, Ceco can customize the metal building for you. For a custom metal building, find a builder near you or contact us.
Have a product question?
We’re happy to give you a helpful answer. Simply contact Ceco for detailed information on any of the steel building system products we offer, from primary framing systems to our wide range of accessories.