DESIGN GUIDE - Interstate Brick

DESIGN GUIDEFORSTRUCTURAL BRICK VENEERPrepared for:Western States Clay Products Associationwww.wscpa.usSubmitted by:KPFF Consulting Engineers1601 5th Ave. Suite 1600Seattle, WA 98101Second Edition, July 2004

STRUCTURAL BRICK VENEERAcknowledgmentsThe Design Guide for Structural Brick Veneer was sponsored by Western States ClayProducts Association and written by KPFF Consulting Engineers. Principal-in-Chargefor KPFF was John G. Tawresey. The preparation of the report was directed by theTechnical Committee of the Western States Clay Products Association. The authors areappreciative of the help provided by Jim Anderegg, Mutual Materials Company, JamesAmrhein, Gregg Borchelt, Brick Institute of America, Jeff Elder, Interstate BrickCompany and Don Wakefield.John G. Tawresey, KPFF Consulting Engineers prepared the 2004 Second Edition.The material presented in this publication, including technical and engineering data,figures, drawings and tables, is for general information only. It should not under anycircumstances be relied upon for specific applications of the Structural Brick Veneerwithout independent evaluation by a licensed design professional familiar with itsspecific use and application. Anyone making use of this material does so at their ownrisk and assumes any and all liability resulting from such use.Copyright 2004 by Western States Clay Products Association,All rights reserved. No part of this publication may be reproduced, stored in a computer or retrievalsystem or transmitted in any form or by any means, electronic, mechanical, photocopy, fax, recording orotherwise, without the prior written consent of the author or Western States Clay Products Association.Western States Clay Products Association2July 2004

STRUCTURAL BRICK VENEERSummaryStructural Brick Veneer is a unique approach to the design and construction of brickexterior walls. Strengthening the brick with steel reinforcement provides new opportunities for reducing the cost of the wall, increasing design flexibility and improving wallperformance. In use for more than thirty years, the approach has been used extensivelyin the Pacific Northwest.The Structural Brick Veneer system is similar to conventional brick veneer except thatthe brick is reinforced to allow it to span further between ties and supports. The systemallows the architect a variety of opportunities to create traditional walls or dramatic brickforms. Sloping windowsills, brick soffits, lintels without exposed ledger angles andprecast concrete bands and inserts are only a few examples of the design opportunitiesavailable.In areas of high seismic exposure, the Structural Brick Veneer system can be easilyisolated from the primary structure making “immediate occupancy” performance morecost effective.The following document will provide the structural engineer and the architect with anintroduction to the design and specification of the Structural Brick Veneer system. Itincludes some design examples and dialogue on our experiences with the system overthe past 20 years.Western States Clay Products Association3July 2004

STRUCTURAL BRICK VENEERList of FiguresFIGURE 1 TYPICAL HOLLOW BRICK .8FIGURE 2 TYPICAL STRUCTURAL BRICK VENEER CONNECTOR .8FIGURE 3 BRICK SUPPORTED ON A LEDGER.8FIGURE 4 TYPICAL STRUCTURAL BRICK VENEER DEADLOAD CONNECTOR .8FIGURE 5 DEAD LOAD ON THE FOUNDATION .9FIGURE 6 FLEXIBLE CONNECTORS.9FIGURE 7 SLOPING SILL BRICK SOFFITS .10FIGURE 8 BRICK SOFFIT .10FIGURE 9 PRECAST IN STRUCTURAL BRICK VENEER .11FIGURE 10 BRICK EXPANDING RESISTED BY THE REINFORCEMENT .12FIGURE 11 CRACKED BRICK .17FIGURE 12 DIFFERENTIAL VERTICAL DEFLECTION.18FIGURE 13 HORIZONTAL DRIFT JOINT .18FIGURE 14 CORNER CONNECTED TO THE STRUCTURE .19FIGURE 15 CORNER NOT CONNECTED TO THE STRUCTURE .19FIGURE 16 HOSPITAL - PROJECT 1 .21FIGURE 17 PROJECT 1 – PIER CONCEPT BETWEEN WINDOWS .22FIGURE 18 LATERAL CONNECTION.22FIGURE 19 DRIFT JOINT BEFORE LEDGER INSTALLATION .23FIGURE 20 LEDGER INSTALLATION .23FIGURE 21 PROJECT 2.23FIGURE 22 HOSPITAL WITH MANY CORNERS .24FIGURE 23 TEMPORARY RIGID FOAM BOARD SUPPORT .24FIGURE 24 CONSTRUCTION SEQUENCE .25FIGURE 25 BUILDING WITH ANTICIPATED DIFFERENTIAL SETTLEMENT .25FIGURE 26 CONCEPT FOR SETTLEMENT .26FIGURE 27 STIFFNESS OF BRICK MASONRY .27FIGURE 28 STRIP SYSTEM EXAMPLE .29FIGURE 29 SUPPORT FOR THE WALL .29FIGURE 30 BRICK USED IN THE EXAMPLE .30FIGURE 31 PLAN VIEW OF CONNECTOR.32FIGURE 32 SIMPLE LATERAL CONNECTOR .34FIGURE 33 FINAL DESIGN .36FIGURE 34 LOCATION OF CONNECTORS .36FIGURE 35 PLAN VIEW OF CONNECTOR.37FIGURE 36 DEAD LOAD CONNECTOR .38FIGURE 37 DEAD LOAD MOMENT .38FIGURE 38 RESISTING MOMENT .39FIGURE 39 WARPING CORNER .41FIGURE 40 FLUID GROUT .43FIGURE 41 PROTRUDING FLASHING DETAIL .45FIGURE 42 FLUSH FLASHING DETAIL .45FIGURE 43 VARIATION OF FIELD MORTAR TESTS .54FIGURE 44 MORTAR 7 DAY AND 28 DAY TESTS .54FIGURE 45 VARIATION OF FIELD GROUT TESTS .54FIGURE 46 SEVEN DAY AND 28 DAY GROUT STRENGTH .55Western States Clay Products Association4July 2004

STRUCTURAL BRICK VENEERList of Figures .41.0 Introduction .61.1 Purpose & Scope.61.2 History of the System.62.0 System Description .72.1 Structural Concept.72.2 Concept Configurations .92.3 Weather Protection .113.0 Design.123.1 Who Designs the Wall? .123.2 Design Criteria .133.3 Designing the Wall .213.4 Design Examples .294.0 Specification .424.1 Quality Control and Assurance.424.2 Masonry .434.3 Steel for Connectors .444.4 Flashing/Weeps .444.5 Sealants .454.6 Water Repellents .454.7 Backup Wall .474.8 Cavity .474.9 Expansion Joints .474.10 Window Anchorage.485.0 Construction .485.1 General.485.2 Construction Sequence .495.3 Pre-Construction .495.4 Submittal Review.515.5 Site Visits.525.6 Non-Conforming Quality Control Tests.535.7 Troubleshooting During Construction .566.0 Testing .606.1 Air.606.2 Water .606.3 Structural .60Western States Clay Products Association5July 2004

STRUCTURAL BRICK VENEER9. Greater resistance to cracking.10. Greater water resistance.1.0 IntroductionStructural Brick Veneer is the name thatwe have chosen to describe hollow reinforced clay brick curtainwall systems.These systems commonly replace brickveneer walls.The system has been used on morethan 100 projects over the last 20 years.1.1 Purpose & ScopeThe purpose of this guide is to providethe architect, structural engineer andowner with information about the designand construction of Structural BrickVeneers. It is intended to be easilyunderstood by someone experiencedwith reinforced brick masonry designand construction. For those not familiarwith the design of reinforced brickmasonry, the Western States ClayProducts Publication, “Notes on theSelection, Design and Construction ofReinforced Hollow Clay Masonry” isrecommended.The Structural Brick Veneer system issimilar to conventional brick veneerbecause it supports no gravity loadsother than its own weight, the weight ofwindows, and possibly other miscellaneous loads. The difference is that inthe Structural Brick Veneer system themasonry is reinforced to allow the brickto span further between ties and providestructural capacity to create more intricately shaped walls.Structural Brick Veneer can be laid inplace similar to conventional brick veneer, or they can be prefabricated atanother location and lifted and installedto their final position.As the design and construction ofreinforced brick masonry varies fromlocation to location, so does the designand construction of Structural BrickVeneer vary from location to location.The information and recommendationsin this guide are based on the designand construction of projects in thePacific Northwest and are not intendedto replace local experience and engineering judgment.The system has many advantages overconventional brick veneer. Some ofthese advantages are:1. Greater design flexibility.2. Reduced backup requirements.3. Enhanced design life through heavier connections.4. Reduced tie connections, whichprovides more continuous moisturebarrier.5. Greater seismic resistance andmore ductility.6. Less restrictive deflection requirements of the backup structure.7. Reduced cost of the backup system.8. Often lower construction cost.Western States Clay Products Association1.2 History of the SystemThe origin of Structural Brick Veneerdates back to the early sixties. In 1962,a mechanical equipment penthouse wasbuilt on top of the nine-story UnitedFund office building in Denver,Colorado.The 15-foot high, load6July 2004

STRUCTURAL BRICK VENEERbearing, 4-inch thick clay brickprefabricated panels supported longspan, prestressed, twin-tee concreteslabs that were the roof structure of thepenthouse. This construction was madepossible by the use of a new "tensilestrength intensive" exotic mortar andsome backup steel reinforcing.This thinner reinforceable, hollow clayunit was more economical, ductile,flexible and more predictable; thusexpanding its use in commercial curtainwall systems as well as ment buildings, and prefabricatedpanels.This 4-inch brick and exotic mortarsystem was used for several yearsthereafter in the Colorado area inprefabricated and in situ, hand-laid brickpanel and curtainwall applications onmany commercial buildings designed byGeorge Hanson, P.E. of the firm ofSallada & Hanson, Engineers. Thisstrong thin-wall system intrigued thedesigners who used this system on horizontal soffits, cantilevered balconyrailings, post-tensioned panels, loadbearing and non-load-bearing walls onschools, office buildings, hospitals, thewalls in vehicular tunnels, highway restarea toilet modules and picnic shelters.Even though this brick curtainwallsystem was very successful, it was relatively expensive due to the use of thehigh tensile strength mortar.During the 1970's, a similar system wasdeveloped and p

field, P.E. of the Structural Clay Products Institute developed, in Colo-rado, a new clay unit and method of construction that reduced the cost and allowed for the use of regular reinforcing and standard mortar and grout. This unit was a 3-1/2" x 3-1/2" x 11-l/2" hollow clay brick using ASTM C-212 recommendations. This system accom-