JEI Structural Engineering

Museum of Contemporary Art Cleveland – Project Videos

admin — Sat, 05 May 2012 15:05:55 +0000

JEI Structural Engineering completed design calculations for the sloped curtain wall and sloped strip windows for the Museum of Contemporary Art Cleveland, working with Zahner.

CONSTRUCTION Video

Hogle Zoo Rocky Shores Exhibit by JEI Structural Engineering

admin — Sat, 05 May 2012 14:51:42 +0000

JEI Structural Engineering completed the glass viewing exhibit window design for The Rock Shores exhibit includes polar bears, three grizzly bears, three seals, three sea lions, river otters and bald eagles, according to Hansen.

The Future of Glass Technology

admin — Sat, 05 May 2012 14:34:09 +0000

Here is a conceptual video created by Corning Incorporated in “A day made of glass.” It goes through what would be your typical day scenario waking up at your beautiful luscious estate in pleasantville. Followed by various interaction with every piece of glass you encounter throughout the day being touch sensitive, electronic enabled displays. This is a novel idea and common representation of the future where all surfaces are interactive. This concept was focused around the future of glass. How soon do you think this glass future will be a reality, and what future elements would you like to include?

Lion mistakes baby for zebra. Attacks glass.

admin — Sat, 05 May 2012 14:25:54 +0000

A lion at the Portland Oregon Zoo mistakes a baby in a black and white striped “zebra” outfit. The dynamic analysis of impact on glass is very, very important to animal viewing window enclosures.

Gorilla Breaks Glass at Atlanta Zoo

admin — Sat, 05 May 2012 13:58:25 +0000

Zoo Atlanta resident, Taz, a 360-pound gorilla that went ape, frightened visitors and caused the closure of the gorilla viewing area. According to reports from the AJC and 11 Alive, the 20-year-old silver back gorilla charged and then slammed his fists into the barrier at the Willie B. Conservation Center, thus cracking the thick glass and prompting the immediate evacuation of the viewing area.

The dynamic analysis of impact on glass is very, very important to animal viewing window enclosures. Has anyone heard how thick this glass was?

When Good Projects Go Bad – tips for glazing contractors

admin — Tue, 01 May 2012 17:19:37 +0000

These glazing scope items can mean the difference between a profitable job and a costly mistake

By Anthony Callas April 30, 2012

A misunderstood or poorly documented glazing scope is one of the simplest ways a good project can go bad for contract glaziers. Any number of problems can arise if the entire glazing scope is not accurately communicated in a bid proposal or errors are not properly discovered in the scope review. When parties are unclear on scope, they enter the job with a gap between their expectations. The job is not set up for success for the general contractor, subcontractors, owner, supplier or other players. Following is a list of commonly overlooked or misunderstood scope items that concern contract glaziers. By carefully examining the glazing scope for the following issues, glaziers can avoid costly problems, and submit the most accurate and thorough bid.

Openings do not correlate between floor plans and elevations Glaziers should carefully crosscheck floor plans and elevation drawings to ensure the glazing openings and components coincide.

Design drawing omissions Some design elements, such as soffits, returns and transitions, are commonly missing from elevation drawings when the drawings don’t cover every elevation. Look at every surface in the scope to ensure you don’t miss any elements.

Scope not labeled Surfaces are frequently not labeled on scope drawings and are instead depicted using colors or hatch patterns. However, these patterns are not always consistent: A dot pattern on the West elevation might depict plaster, while on another elevation the same dot pattern might depict another surface material. If surfaces are not labeled, cross-reference scope documents completely to avoid missing any bid items.

Technical hardware Doors typically have door closures, thresholds, and in some instances, technical hardware such as magnetic locks, card readers and electrified hinges. These items are not always included on the door schedule and in the specifications.

Mock-up and testing Clarify the mock-up and testing requirements if they are omitted in the scope. Ensure you know whether the project needs a performance mock-up in the lab or field, and whether tests will be required in the lab or field.

Moisture barriers Scopes often address moisture barriers, including provisions for items such as the line of sealant. Contract glaziers need to look for details about moisture barriers, as sometimes the glazier is responsible, and sometimes the responsibility falls on another trade.

Exhibit scopes in contracts Every contract will have a variety of exhibit scopes—sometimes a dozen different exhibits. Make sure you know and master the scope exhibits, as these define what is in the glazing package, whether you’ll have final clean-up, protection of work, etc.

Contract terms Make sure the contract terms are clearly laid out to avoid confusion on items such as change orders, insurance requirements and payment terms.

General conditions Clarify general contract terms, such as what you will need to provide on the jobsite: a foreman, administrative personnel, WiFi and other basic overhead items. The general contract terms should also specify physical jobsite characteristics, such as access restrictions, that could affect the type of equipment and access required for installation.

Additional provisions Scopes might include additional provisions, such as a requirement to carry additional dollar allowances. Neglecting to include them could result in artificially low bids.

Schedule Ensure the scope outlines a realistic schedule for your trade. Don’t make promises you know you can’t keep.

Supplier payment terms Some glass and glazing material suppliers require specialized payment terms, such as 50 percent down before the project proceeds. Notify the general contractor of these terms and ensure that you bill for the specialized payments sufficiently.

The author is director of operations for Heinaman Contract Glazing. Printed in eglass weekly.

Architectural Q&A regarding Blast Design Requirements

admin — Thu, 05 Apr 2012 21:44:34 +0000

QUESTION

I am an architect currently working on a design competition for a project that will require blast resistant windows. I’m curious about the note stating the connections will be difficult for small windows. What dimension would you define as a small window? Our schematic has some smaller windows in stairs and in this phase of competition we certainly want to show something that is feasible.

5) Connections and anchors under static equivalent method is changed. The connections and anchors must be designed for either 1x or 2x the glazing resistance instead of the typical loop holes that we have seen 2x the 3-second load (usually 100psf). Anchors and connections at these loads will be difficult if the controlling glazing lite in an elevation is small. I think anchors into masonry and wood and light-gage steel will not be workable with this method.

ANSWER

Well – lets take this example a 20” x 30” window – Insulated glass (1/4” Tempered outside pane and ¼” Heat strengthened inside). When we run the ASTM E-1300 glass resistance numbers on this we are at 680 psf. (See below)

So if the anchor design loads are just 1x the resistance then it would be 680 psf, but if it is 2x then it would be 1360 psf. 680 psf is severe enough, because originally before the UFC change many specs and criteria that we would see would be 2x the 3-sec equiv blast load (usually 2x 50psf = 100psf). So the question is can someone design anchors for this in whatever your substrate is? – This example is almost 7x as much design load as before (a little less than that because we can use ultimate strength methods now – but that’s little relief).

Stewart P. Jeske, P.E.

The updated UFC 4-010-01 (2012) has been released.

admin — Wed, 21 Mar 2012 16:11:07 +0000

Based on a quick review, here are the major changes/impact that I see:

1) The biggest change – Conventional Construction Stand-Off Distances. This is a huge change! They have reidentified the conventional construction stand-off distances in Table B-2 based on the wall type construction. I anticipate the net effect will be a moving to wall construction which minimizes the construction stand-off due to spacial constraints associated with military bases. So for reinforce masonry and concrete and wood studs w/brick that means about 30 feet and 16 feet and 36 ft respectively! Glazing systems with these requirements will not likely be able to have static equivalent calculations performed – They will be forced to dynamic analysis. I anticipate that these types of installations will start showing up late summer to fall of this year.

2) Another major impact – Testing Requirements. This is also huge! The requirements state that the testing must meet the appropriate pressure and impulse from the applicable standoff and explosive weight. So, given the changes with the Conventional Construction Stand-Off Distances most all of the manufacture’s blast testing (at 82′ Ex weight II and 144′ Ex weight I) will be obsolete! I feel badly for all of the manufacture’s who have invested a great deal of effort and resource to testing in the past 5 years.

3) Dynamic analysis is pushed. Under paragraph B-3.1.3 ASTM F 2248 Design Approach (This is the 3-second static equivalent method) they state, “In order to reduce the conservatism associated with using the ASTM methodology, the window systems may be designed using dynamic analysis or tested …”

4) Framing calculations under the static equivalent method is changed. Framing must now be shown adequate with a design load of 2x the glazing resistance instead of the 3-second equivalent blast load. In some cases (with small glass lites governing – Its usually the case that the Architect is unaware) this will be the difference between 50psf (typical 3-sec load) and 400 – 1200 psf! L/60 is used as a deflection limit now instead of L/160, but I don’t think that will help much – sections will need to be much stronger using this method.

5) Connections and anchors under static equivalent method is changed. The connections and anchors must be designed for either 1x or 2x the glazing resistance instead of the typical loop holes that we have seen 2x the 3-second load (usually 100psf). Anchors and connections at these loads will be difficult if the controlling glazing lite in an elevation is small. I think anchors into masonry and wood and light-gage steel will not be workable with this method.

6) We are now able to Use ultimate strength design instead of allowable stress, but again this helps little in light of the major changes above.

Stewart Jeske, P.E.

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New Criteria in Aluminum Code Translates to More Cost for Glazing Contractors

admin — Fri, 03 Feb 2012 19:56:16 +0000

Great article publised in US Glass by Sahely Mukerji quoting Stewart Jeske and some of our clients about important storefront issues. Read the short article here.

Gathering Missing Information on Blast Projects Saves Time

admin — Tue, 31 Jan 2012 19:48:42 +0000

Many blast project specs do not provide enough information to come up with the equivalent 3-second blast design pressure from ASTM F2248. Glazing contractors can save time by requesting the following information in advance.

Explosive Weight – (Typically for most projects explosive weight II)
Standoff Distance – (For most projects it is the Conventional Construction Stand Off = 82 ft)
Level of Protection – (Typically Low Level of Protection)

This criteria is usually determined during the design phase of a project by the using agency or the design team.

For more helpful information on blast projects see JEI Structural Engineering WINGARD, Windas, Window Blast, Blast Mitigation Design