enhanced performance through optimized masonry … · to have gained insight into masonry lintel...

ENHANCED PERFORMANCE THROUGH OPTIMIZED MASONRY LINTELS

Presented by Scott W. Walkowicz, P.E.For the Indiana/Kentucky Structural Masonry Coalition

COPYRIGHT WALKOWICZ CONSULTING ENGINEERS 2019 1

ALL SEASONS BUILDING MATERIALS

A REGISTERED INDIANA PDH PROVIDER

INDIANA/KENTUCKY STRUCTURAL MASONRY COALITION

This presentation is protected by U.S. and International copyright laws. Reproduction, distribution, display and use of the presentation without permission of the speaker is prohibited.© Walkowicz Consulting Engineers, LLC

THIS PRESENTATION IS INTENDED FOR THE USE OF INDUSTRY PROFESSIONALS WHO ARE COMPETENT TO EVALUATE THE SIGNIFICANCE AND LIMITATIONS OF THE INFORMATION PROVIDED HEREIN. THIS PUBLICATION SHOULD NOT BE USED AS THE SOLE GUIDE FOR MASONRY DESIGN AND CONSTRUCTION, AND WCE AND MISMC DISCLAIMS ANY AND ALL LEGAL RESPONSIBILITY FOR THE CONSEQUENCES OF APPLYING THE INFORMATION.

To have gained insight into masonry lintel detailing performance benefitsTo demonstrate masonry lintel structural performance benefitsTo illustrate structural design approachesTo recognize the overall building improvements gained through the use of masonry lintels

Steel lintels can add 6-8 weeks… to as much as 12 weeks delayWith Masonry Lintels:◦Differential movement eliminated◦Detailing dramatically better (flashing and steel infill)◦ Thermal bridging reduced◦ Control joints reduced (see Structural Performance…)◦Wide cavity options

Steel lintels can add 6-8 weeks… to as much as 12 weeks delay

Steel lintels cause delays…◦add 6-8 weeks…◦to as much as 12 weeks delay

Detailing / Review / ?Revision? / Fabrication / Galvanizing

Detailing dramatically better (flashing and steel infill)Thermal bridging reduced

Figure Credits: Masonry Institute of Michigan

Different Example Details

Figure Credits: International Masonry Institute

Figure Credit: Masonry Institute of Michigan Figure Credit: GMB

Figure Credit: Masonry Institute of Michigan

Detailing dramatically better (flashing and steel infill)

Use masonry modules for length, height and position!

Detailing dramatically better (flashing and steel infill)Thermal bridging reduced eliminated…Works for wide cavities

Proprietary or project specific engineered outrigger angleThermal bridging reduced minimized…Works for wide cavities…

Figure Credits: FERO

(Shelf angle detail)

Proprietary or project specific engineered outrigger angleThermal bridging reduced minimized…Works for wide cavities…

Figure Credits: Halfen(Shelf angle detail) Halfen FK4 Brickwork Support System

Control joints better placed for better wall structural performance◦Greater effective ‘pier’ width◦Masonry wall or wall-frame performance

Span large openingsEasier to achieve lower deflectionHandle torsion and shear better with less complicationDeep beam optionDoubly Reinforced

Control joints better placed for better wall structural performance◦Reduced number of joints◦Reduced length of joints◦Better jamb reinforcement

Figure Credit: GMB

Control joints better placed for better wall structural performance

Figure Credit: International Masonry Institute

(See NCMA TEK 10-3 re. eliminating CJ’s)

Span large openingsEasier to achieve lower deflection

◦ 7 cs. CMU = 0.145”◦W16x36 = 0.376”

Figure Credit: DeMattia

24’-8”40’-0”

Span large openingsEasier to achieve lower deflection

48’-0”

Figure Credits: MayotteGROUP Architects

8 cs. CMU = 0.50”W24x117 = 1.15”

Handle torsion and shear better with less complication◦ Torsion becomes moment in the adjacent pier◦No torsion provisions in masonry code◦ Historically no beams fail in torsion◦ Wide cavities with heavy veneer loads may change that…

◦ Shear generally very low compared to capacity

Handle torsion and shear better with less complication

Figure Credits: Bergmann

Figure Credit: GMB

Figure Credit: NCMA TEK 10-2C

Consider load balancing to reduce eccentric loading and keep bearing plate loose by keeping reaction in center 1/3 of bearing (kern) of the lintel plate which is coped to 5/8” less than wall thickness beyond M.O. See design example….

Or, run the lintel plate through the full length and use it to resist rotation? With no EJ at M.O. or lintel ends? How much differential movement is acceptable???

�116 "?�1

8 "?�1

Figure Credit: GMB

Simple span with or without arching actionFixed-end / continuousDeep beamDoubly ReinforcedWide cavity options◦Outriggers◦Reinforced veneer

The basics:

The basics:Know your depth: 2.25” or 2.75” to bottom of bars?

The basics:Know your depthAnd detail it!

Figure Credits: Bergmann

½” CLR. MIN.

The basics:Know your depth (H – 3” max.?)Use the proper f’m (2300*** psi min.?)Grout more depth rather than stirrupsSelect and detail for end conditions◦ Simple span with CJ’s/EJ’s◦ Continuous with joints moved off the end

of lintel

Figure Credits: Masonry Structures Behavior and Design 4th Edition (Hamid)

Simple Span – the traditional approachFor Uniform Loads:◦𝑀𝑀 = 𝑊𝑊𝑙𝑙2

◦𝑉𝑉 = 𝑊𝑊𝑙𝑙2

Figure Credit: NCMA TEK 17-01D1

Simple Span – the traditional approach◦𝑀𝑀 = 𝑊𝑊𝑙𝑙2/8◦𝑉𝑉 = 𝑊𝑊𝑙𝑙/2

Arching Action?◦ CJ’s can inhibit arching◦No point loads within◦𝑀𝑀 = 𝑊𝑊𝑙𝑙/6◦𝑉𝑉 = 𝑊𝑊/2

Figure Credit: NCMA TEK 17-01D1

Simple Span – Hand CalculationsPure Flexure (ASD) Capacity:◦𝑀𝑀 = 𝑓𝑓′𝑚𝑚𝑘𝑘𝑘𝑘𝑘𝑘𝑑𝑑2

2(compression/masonry controls)

◦𝑀𝑀 = 𝐴𝐴𝑠𝑠𝑓𝑓𝑠𝑠𝑗𝑗𝑗𝑗 (tension/steel controls)◦ 𝑘𝑘 = 2𝑛𝑛𝜌𝜌 + (𝑛𝑛𝜌𝜌)2− 𝑛𝑛𝜌𝜌◦ 𝑗𝑗 = 1 − 𝑘𝑘

◦ 𝑓𝑓𝑣𝑣 = 𝑉𝑉𝐴𝐴𝑛𝑛𝑛𝑛

≤ 𝐹𝐹𝑣𝑣◦ Hand calcs or spreadsheets◦ (works for non-loadbearing walls)

Simple Span – Hand CalculationsTrial:◦M.O. = 9’-4”◦ habove = 6’-0” total◦ Tributary Width = 36’-4” / 2 = 18’-2”◦ Include bolted angle veneer weight / ignore torsion◦DLr = 364 plf / DLveneer = 240 plf / LLr = 364 plf / SnL = 421 plf◦Bearing length = 8” each side (Design Span = 10’-0”)◦DL + SnL = 604 + 421 = 1025 plf + wall wgt. + lintel weight

Simple Span – Hand Calc’sLintel Weight:◦ Try (3) courses:◦NCMA TEK 17-01: 174 plf/ft.

Wall Weight:◦NCMA TEK 14-13B◦ 47 psf = 188 plf at 4’

remaining above lintel

Simple Span – Hand CalculationsDL + SnL + lintel wgt. + wall wgt. = 604 + 421 + 174 + 188 plfTotal Load = 1,387 plf

𝑀𝑀 = 1,387∗102

8= 17,337.5 lb.-ft. = 208,050 lb.-in.

𝑉𝑉 = 1,387∗102

= 6,935 lbs.◦ Conservative to use full shear◦ Typically can use shear at d/2 from support (uniform loading)

At 𝑗𝑗 = 20.5" and 𝑙𝑙 = 7.625′: 𝑉𝑉 = 1,387𝑥𝑥7.6252

= 5,288 lbs.

Simple Span – Hand CalculationsDL + SnL + lintel wgt. + wall wgt. = 604 + 421 + 174 + 188 plfTotal Load = 1,387 plf

𝑀𝑀 = 208,050 lb.-in. ≤ 𝑓𝑓′𝑚𝑚𝑘𝑘𝑘𝑘𝑘𝑘𝑑𝑑2

2OR ≤ 𝐴𝐴𝑠𝑠𝑓𝑓𝑠𝑠𝑗𝑗𝑗𝑗

𝑛𝑛 = 29,000,000 𝑝𝑝𝑠𝑠𝑝𝑝900𝑥𝑥2,000 𝑝𝑝𝑠𝑠𝑝𝑝

= 16.11

𝜌𝜌 = �𝐴𝐴𝑠𝑠𝑘𝑘𝑑𝑑 = ⁄0.44

7.625𝑥𝑥20.5 = 0.00281𝑘𝑘 = 0.2592𝑗𝑗 = 0.9136

Simple Span – Hand Calculations

𝑀𝑀 = 208,050 lb.-in. ≤ 𝑓𝑓′𝑚𝑚𝑘𝑘𝑘𝑘𝑘𝑘𝑑𝑑2

2OR ≤ 𝐴𝐴𝑠𝑠𝑓𝑓𝑠𝑠𝑗𝑗𝑗𝑗

𝑀𝑀𝑐𝑐𝑐𝑐𝑐𝑐𝑝𝑝 = 𝑓𝑓′𝑚𝑚𝑘𝑘𝑘𝑘𝑘𝑘𝑑𝑑2

2= 2,000(0.2592)(0.9136)(7.625)(20.52)

𝑀𝑀𝑐𝑐𝑐𝑐𝑐𝑐𝑝𝑝 = 758,816 lb.−in. ≥ 208,050 → 𝑶𝑶𝑶𝑶𝑀𝑀𝑡𝑡𝑡𝑡𝑡𝑡𝑠𝑠 = 𝐴𝐴𝑠𝑠𝑓𝑓𝑠𝑠𝑗𝑗𝑗𝑗 = 0.44 32,000 0.9136) 20.5𝑀𝑀𝑡𝑡𝑡𝑡𝑡𝑡𝑠𝑠 = 263,702 lb.−in. ≥ 208,050 → 𝑶𝑶𝑶𝑶

Simple Span – Hand Calculations𝑉𝑉 = 5,288 𝑙𝑙𝑙𝑙𝑙𝑙.≤ (𝐹𝐹𝑣𝑣𝑐𝑐 + 𝐹𝐹𝑣𝑣𝑠𝑠)𝛾𝛾𝑔𝑔(𝐴𝐴𝑡𝑡𝑣𝑣)Avoid using stirrups, so only use masonry shear capacity𝛾𝛾𝑔𝑔 = 1.0 𝑓𝑓𝑓𝑓𝑓𝑓 𝑓𝑓𝑜𝑜𝑜𝑜𝑜𝑓𝑓 𝑜𝑜𝑜𝑡𝑡𝑛𝑛 𝑝𝑝𝑡𝑡𝑓𝑓𝑜𝑜𝑝𝑝𝑡𝑡𝑙𝑙𝑙𝑙𝑝𝑝 𝑔𝑔𝑓𝑓𝑓𝑓𝑔𝑔𝑜𝑜𝑜𝑜𝑗𝑗 𝑙𝑙𝑜𝑜𝑜𝑡𝑡𝑓𝑓 𝑤𝑤𝑡𝑡𝑙𝑙𝑙𝑙𝑙𝑙

𝐹𝐹𝑣𝑣𝑐𝑐 = 12

4.0 − 1.75 𝑀𝑀𝑉𝑉𝑑𝑑𝑛𝑛

𝑓𝑓𝑓𝑐𝑐 + 0.25 𝑃𝑃𝐴𝐴𝑛𝑛

Use M at 7.625’ / 2 from center… d/2 from face

Simple Span – Hand Calculations

𝐹𝐹𝑣𝑣𝑐𝑐 = 12

4.0 − 1.75 87,0895,288(23.625)

2,000 +

0.25 07.625(23.625)

𝐹𝐹𝑣𝑣𝑐𝑐 = 62.164 𝑝𝑝𝑙𝑙𝑝𝑝𝑉𝑉𝑎𝑎𝑙𝑙𝑙𝑙𝑐𝑐𝑎𝑎 = 𝐹𝐹𝑣𝑣𝑐𝑐𝐴𝐴𝑡𝑡𝑣𝑣 = 62.164 ∗ 7.625 ∗ 23.625 =11,198 𝑙𝑙𝑙𝑙𝑙𝑙.𝑉𝑉𝑎𝑎𝑙𝑙𝑙𝑙𝑐𝑐𝑎𝑎 = 11,198 𝑙𝑙𝑙𝑙𝑙𝑙.≥ 5,288 → 𝑶𝑶𝑶𝑶

Simple Span – design aids – NCMA TEK 17-01D1

Simple Span – SMDS

Fixed-end / continuous◦ Top steel required◦Reduced moment◦Reduced deflection◦Moment transferred

to jambs

Fixed-end / continuous – Hand/SMDS◦ Calculate fixed end (negative) moments and shears◦ Remember shear check at d/2 from face◦ Or conservatively use shear at face and assume 𝑀𝑀

𝑉𝑉𝑑𝑑𝑛𝑛= 1.0

◦ Remember that top bars must be developed (length, hooks, etc…)◦ Use TMS 402 development length equation

◦Design top steel / check shear capacity to avoid stirrups◦ Calculate mid-span (positive) moment◦Design bottom steel (shear won’t control here…)

Fixed-end / continuous – Hand/SMDS◦Use the same example as before, but with fixed ends

◦𝑀𝑀𝑡𝑡𝑡𝑡𝑑𝑑𝑠𝑠 = 𝑎𝑎𝑙𝑙2

12= 1025∗102

12= 8,541 𝑙𝑙𝑙𝑙.−𝑓𝑓𝑜𝑜. = 102,500 𝑙𝑙𝑙𝑙.−𝑝𝑝𝑛𝑛.

◦𝑉𝑉 = 1,025∗102

= 5,125 lbs. (at face, conservative)◦ Enter directly into SMDS◦Or, conduct hand or spreadsheet calculations…

Fixed-end / continuous –SMDS

Fixed-end / continuous – FEA (Ram Elements or RISA for design)

Ram Elements Lintel Results:𝑀𝑀 = 9,385 𝑙𝑙𝑙𝑙.−𝑓𝑓𝑜𝑜.𝑀𝑀 = 112,620 𝑙𝑙𝑙𝑙.−𝑝𝑝𝑛𝑛.Remember F-F:𝑀𝑀 = 102,500 𝑙𝑙𝑙𝑙.−𝑝𝑝𝑛𝑛.

Ram Elements FEA:

DL + SnL Deflection in Y DL + SnL M)min

Ram Elements Wall Results:

Deep beams (low span:depth)◦ 3:1 for continuous beams◦ 2:1 for simply supported beams◦Non-planar behavior◦Bottom reinforcement = tie◦Distributed steel required in

tension zone◦ Prescriptive vertical shear steel

Figure Credits: Masonry Structures Behavior and Design 4th Edition (Hamid)

Deep beam option (code specific requirements)

H/L > 2 @simple spanH/L > 3 @continuous

Doubly Reinforced◦ Like concrete beam design◦Utilize top bars in compression◦Will require stirrups to position top bars◦Not typical◦ Can help with minimizing depth

Doubly Reinforced◦Not common◦ Lintel capacity generally

controlled by flexural tension or shear

◦ Top bars must be confined (ties) – adds complication

◦Modest strength increase

Wide cavity options◦Outriggers◦Reinforced veneer

Reinforced veneer lintels - IRC

Reinforced veneer lintels – Hand Calculations◦ Same principals as before◦Different unit strengths, so different f’m◦Different reinforcement size◦ Two or three layers, so ‘d’ calculated to center of mass of group◦ Lateral load taken out by veneer ties◦Beam braced laterally by veneer ties

Masonry lintels offer much improved detailingMasonry lintels lead to better structural performanceMasonry lintel design is not that challengingMasonry buildings perform better with masonry lintels

Scott Walkowicz, P.E., N.C.E.E.S.Walkowicz Consulting Engineers

(517) 339-0314scott@walkowiczce.com

Joe AlbertsInternational Masonry Institute - Michigan

(317) 872-3426jalberts@imiweb.org

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