at/fp challenges in renovation of existing military facilities presented by: david dickey, pe
TRANSCRIPT
AT/FP Challenges in Renovation of Existing Military Facilities
Presented by:David Dickey, PE
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Anti-Terrorism Standards
UFC 4-010-01
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Triggers for Compliance
Is compliance mandatory? Not all renovations must comply with
standards. Triggers
– Renovation costs > 50% Replacement Cost– Conversion of Use– Glazing Replacement Projects– Building Additions– Leased Buildings
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Information Gathering
Site Investigations Need all As-Built drawings
– Including previous renovations Budget for Site Visits
– Entire design team should attend Reduces RFI’s, Change Orders, and
Conservative Bids
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Information Gathering
Unforeseen Conditions If no As-built drawings exist
– Extensive site investigation required
Unknown materials– Masonry – Unreinforced? – Wood – species, size, spacing?– Concrete – strength?– Steel – grade? weldable?
Testing for material properties – X-ray, samples, destructive testing– Will the design contract fund?
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Information Gathering
Unforeseen Conditions Many items covered by interior finishes
– Asbestos, electrical– Structure for window attachments
Is Selective Demolition possible? Maintenance funding for patching? Increase contingency to cover
unforeseen conditions? Unforeseen conditions can exceed 5%
contingency quickly
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Civil / Site
Force Protection Barriers– Passive
• Curbs• Fencing• Hardscapes• Cable Barriers• Planters• Bollards
WVARNG - AFRC – Kingwood, WV
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Civil / Site
Barriers– Active
• Wedge barriers• Pop-up bollards
Source: www.multi-barrier.com
Source: www.herculesfencenc.com
Source: www.herculesfencenc.com
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Architectural
Eliminate external roof access Main entrance facing installation perim.
– Occupants may use different entrance, or– Screen the front entrance
Maintain Aesthetics
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Architectural / Civil
Fencing
Source: www.ameristarfence.com
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Architectural / Civil
Landscaping
Command & Control Fac. – Ft. Campbell, KY
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Architectural / Civil
Landscaping
NOSC – El Paso, TX
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Mechanical
Enclose Units Within 33ft of Building
NOSC – El Paso, TX
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Mechanical
Louver locations 10’ above ground– Not mandatory, but desirable– Could duct through roof– Use 2nd floor space as Mech. Rm.
Bracing of suspended equipment– Difficult to access if ceiling is not being
replaced
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Mechanical / Electrical
Mailroom Addition Requires dedicated ventilation and
exhaust systems Automatic shutoff with low leakage
dampers Tie controls into main DDC system
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Architectural / Structural
Mailroom Addition Seal Walls and Doors Well Harden Walls for Mail Bomb Threat
– Demo existing floor slab– New foundations
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Structural
Prevent Progressive Collapse For buildings 3 stories or more
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Civil / Site
Standoff Distance Biggest issue with existing facilities
New guidance for New Reserve Facilities
ALL standoffs = 148’
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Parking and Roadways– Provide access control at conventional
standoff distance and restrict parking within Minimum standoff distance
Civil / Site
Parking and Roadways– Move parking & roadways
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Civil / Site / Structural
Parking beneath building or on rooftop– Eliminate– Access Control– Blast analysis for Type II explosive
• Beneath – Reflected blast pressures• Rooftop – No standoff distance to roof structure
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Architectural / Structural
Window Replacement Fragment retention films and blast
curtains no longer acceptable
Window ReplacementWindow Replacement Fragment retention films and blast
curtains no longer acceptable Insulated Glazing Units
– Laminated Glass
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Architectural / Structural
If Standoff Distances are met– Glazing, frames, components, anchors, and
supporting structure must still meet UFC– Wall is considered conventional construction
• No wall retrofit necessary
If Standoff Distances are NOT met– Glazing, frames, components, anchors, and
supporting structure must be designed for higher blast loads
– Wall must be analyzed for blast pressures• Wall/Building retrofit may be necessary
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Architectural / Structural
Window Supporting Structure Static Analysis
– Extremely Conservative Dynamic Analysis
– Less conservative– Qualified blast engineer – Software is becoming easier to use
• SBEDS
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Structural
SBEDS software
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Structural
Results of Window Jamb Design CASE: Brick wall with metal stud
backup, 36”Wx48”H window, 15’ tall jamb– Dynamic Analysis
• One 6” deep 12 Gage stud required per jamb
– Static Analysis• Four 6” deep 12 Gage studs required per jamb
Recommend Using Dynamic Analysis for all projects – New and Existing
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Structural
Retrofit Window Supporting Structure Steel Tubes
– Inset into building– Anchor to slabs below and above
• Difficult with weaker roof or floor system
Unreinforced Masonry Walls– Cut blocks, drill & epoxy rebar, grout solid– Grout solid and reinforce externally
Each project is different
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Key Points
Know Triggers Info: As-built drawings – Site visits Reduce Unforeseen Conditions Site: Barriers, landscaping, aesthetics
Parking will be impacted
Dynamic vs. Static Analysis
Window Replacement
Influence of Standoff Distances
Each project is different