~ :ii:i i:i ~- ~ i } ; i ill: ~i :~ i :~: i:/:i~}i ¸ !iiZ} ~b:v~ .... .~.:.~.: ~: :~¸: ~ ~,,~ !i~,:~' ....... i~:ii i ii% ~, :~i ?i:iiii~:i:~:ii!i!i:iii~ Design and Installation of Exterior Dimension Stone Systems MICHAEL D. LEWIS, AIA ASTM Manual Series: MNL 21 ASTM Publication Code Number (PCN) 28-021095-10 1916 Race Street Philadelphia, PA 19103-1187 Library of Congress Cataloging-in-Publication ataD Modern stone cladding: design and installation ofe xterior dimension stone systems / Michael D. Lewis, editor. p. cm. -- (ASTM manual series: MNL 21) "ASTM publication code number (PCN) 28-021095-10." Includes bibliographical references and index. ISBN 0-8031-2061-3 1. Curtain walls--Design and construction. 2. Stone veneers. I. Lewis, Michael D., 1960- . II. Series. TH2238.M63 1995 693'.1--dc20 95-37436 CIP Copyright 01995 AMERICAN SOCIETY FOR TESTING AND MATERIALS, Philadelphia, .AP All rights reserved. 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Printed in Philadelphia, PA September 1995 J ACKNOWLEDGEMENTS While many contributed immeasurably to this effort, the inexhaustible patience of my wife Marianne and my two sons Jensen and Alexander made this work possible. They sacrificed endless evenings and weekends through the last ten years to study, practice, and share the technology of... "rocks" on buildings. Without their support and infinite patience, this book would not be possible. ABSTRACT /x FOREWORD xi 1 INTRODUCTION TO MODERN STONE CLADDING: Approaching Design with Rational Principles The Professional's Design Responsibility The Development Of CladdiFnugn damentals Boundary Conditions for Stone Cladding Legitimate in Testing Comparison to Existing Skins Organization of the Evaluation ssecorP Engineering Decisions That Derive Designs Makes Partnering This Approach Successful How Future Architecture Benefits from Modern Stone Cladding 2 PRECEDENTS TO MODERN STONE CLADDING: How Stone Became Thin on Building Skins Stone's Tradition sA Shelter The Ascent of the Wall Bearing Wall Metamorphosis Caused by the Iron Skeleton Slender Iron Members Replace Massive Masonry Piers The Masonry Curtainwall sI Born from Fire Commercial Momentum Outpaces Masonry's Conventional Limits Consequences Learned from Freeing the Facade from the Frame Architectural Fashion Exploits a Separate Skin from Skeleton Reluctant Rejection oTfr aditional Style Unexpected Problems with Early "Thin" Walls Engineering Analysis Evolves with Construction Ingenuity Adapting Stone to Fit into Metal Curtainwalls Modernized Dimension Stone Manufacturing Stone's Potential int he Future's Architecture eV iv ° NREDOM ENOTS GNIDDALC THE FUTURE OF STONE CLADDING: Toward Load-And-Resistance Factor Design for Exterior Stone Cladding 23 4 DETERMINING RESPONSIBLE DESIGN VALUES: Formulating Load-And-Resistance Factor Design for Exterior Stone Cladding 27 Failure Means Fracture Risks Compared with Their Consequences Reliability with Changing Variables Load Derivation and Design Applications Consolidated Uncertainties in Current Stone Engineering Segregated Uncertainties in a Limit-State Approach Factors for Loads and Resistances GUIDE SPECIFICATION FOR STONE CLADDING SYSTEMS 39 Scope and Applicability of This Guide Specification Why Thin Stone Requires a Unique Engineering Process The Structure of The Engineering Process A Stone System's Boundary Conditions The Engineering Sequence A Case Study That Applies the Sequence The Approach Related to Existing Practices Standards for Depicting and Specifying Stonework Standards for Presenting Stonework in Contract Documents Limits and Dependencies on Interfacing Work The Abilities Special of a Qualified Stone Cladding Designer Materials Used to Construct Interfacing Systems in Exterior Walls Metal Integrity and Compatibility Joint Function Filler and Capability How to Keep Exterior Joints Weathertight Stone Panel Movement Freedom The Environmental and Structural-Proof Function Of The Joint Isolation of Components That Occupy the Joint Static Effects That Influence Joint Sizing Dynamic Effects That Influence Joint Sizing Effects That Change Horizontal Joint Widths Effects That Change Vertical Joint Widths Testing Used to Design Stone and Its Anchors Factors That Influence Stone and Anchorage Performance An Approach to Objectively Evaluate These Influences Standard Methods from The American Society for Testing and Materials Geological Mineral Compositions of Stones Properties That Affect Natural Stone Structural Performance Tests Sequenced to Quantify Stone-Clad Wall System Characteristics Contents • vii Test Value Interpretation Tests Designed to Evaluate Anchorages Tests Designed to Prove the Capacity of an Assembly Anchorage Device Mechanics The Function of the Stone Anchor Proper Design and Installation Philosophy Correct Anchorage Device Configuration Handling Stone During Installation Basic Anchor Device Types Proper Application and Optimization of Kerfs Proper Application and Optimization of Dowels Case Study Testing Applied to the Design Process ASTM Standard Tests for Material Unit Strengths Theoretical Panel Test by Finite-Element Structural Analysis Actual Panel Test for Preliminary Load Capacity Anchor Capacity and Effective Engagement Length Test Complete Assembly Full-Panel Chamber Test BIBLIOGRAPHY 135 INDEX 137 BSTRAC'I' HIS book documents a sequenced procedure to design exterior dimension stone cladding. The design approach avoids arbitrary safety factors by considering performance variables that can establish true safety and durability. This text presents a process to select, design, and install dimension stone cladding and support systems. Within a sequenced format, extensive explanations with new engineering applications enhance recognized industry practices and include successful exemplars to guide objective and rational decisions. This approach increases awareness of the individual influences that affect exterior wall per- formance. These influences, termed "uncertainties," can each be researched to establish their impact on the risk of failure. They must be correlated to existing work. Evaluated individually, they formulate load and resistance factor design for dimension stone. This approach tends to provide safe and durable stone projects. •/x HE intent of this manual si to outlinteh e process of selecting, designing, and installing stone cladding systems for exterior walls. Stone's physical nature and cladding retention systems vary widely. Their potential applications are widespread. The engineering process should recognize exemplars before tests. Modern construction should include successful walls enduring in the real-world "laboratory." It should not duplicate the failures. These past lessons, not just fresh tests, should guide selection, testing, design, engineering, and installation. This approach identifies those variables known to influence stone cladding system performance. Each variable si considered separately within the process to optimize the solution. Applying this process results in better projects for all parties involved. Better walls are more efficient to construct and maintain. Well con- structed walls are more durable. And more durable walls are safer and create more comfort- able space for the public. This manual is not a code that formulates objective limits. Further structured practice and research can objectively measure the variables that influence perfor- mance. This manual organizes the principles that base such research on those variables. Chapter 1, Introduction to Modern Stone Cladding and Chapter 2, Precedents to Modern Stone Cladding, discuss the history of stone as it evolved into modern "thin," non-loadbearing cladding. Chapter 3 on Determining Responsible Design Values and Chapter 4 on The Future of Stone, outline a variable-based design procedure analogous to load-and-resistance factor design. Chapter 5, Guide Specification for Stone Systems, advises owners, architects, engineers, and contractors about the specialty of modern stonework. This manual comprises a process that assists users to rationally select, design, and install stone cladding for exterior walls. This manual is sponsored by Committee C-18 on Dimension Stone. • xi INTRODUCTION TO MODERN STONE CLADDING: gnihcaorppA Design Rational with selpicnirP gONE is a prominent and desirable building cladding. It was first used in massive blocks stacked within loadbearing masonry walls. It is now commonly a thin-skin caulked cladding, which is only facing. As part of the exterior wall, it does not support the building. Stone's structural role is now flexural as facing instead of compres- sive as blocks, contrary to its natural strength and origin. The newest stone assemblies seem more complicated than conventional masonry construc- tion. Yet, they can still be simple and durable if executed with the proper design and in- stallation techniques. The contemporary approach to engineering stone must consider stone's function and its environment in its intended exterior-wall applications. This manual outlines a process for evaluating the aspects that influence stone cladding per- formance. The process considers existing systems and buildings, testing and engineering, and installation methods to predict performance. Designers and installers following this logical progressive analysis make objective design decisions to validate a design. Because the analysis is sequenced, consistency is reproducible. The results of the process offer con- sistent quality and safety appropriate for the intended application of the stone cladding. Stone is a natural material that possesses variable properties. Using it as a cladding requires consideration of stone's unique characteristics. Also, the behavior of its supporting struc- ture and previous uses exposed to the proposed building's environment must be consid- ered. Both are important for proper performance. This manual describes how to evaluate these influences to maximize stone cladding system's economy, durability, and public safety. THE PROFESSIONALS' nology from being compiled and disseminated. The specialty DESIGN RESPONSIBILITIES subcontractor, as a designer, a manufacturer, and an erector Professionals intimately involved in the design and construc- improves the processb y encountering the difficulties of its own tion of natural stone skins for buildings know that there si a design during installation in the field, and then correcting those significant need for an objective process for completing those deficiencies. Repeating this improves wall quality. tasks. A uniform approach does not presently exist. The exterior wall physically encloses the building. Clad- In this specialized field, a subcontractor si typically del- ding contractors resolve errors in other contractors' previous egated design responsibility and absence of details si com- work by others by covering them. This manual considers per- mon. Contract documents specify a system with performance formance variables to help avoid interference problem condi- criteria and profiles, then subcontractors develop systems from tions. It complements the desipgrno cess by identifying poten- these rules. Subcontractors guard their individual solutions to tial conflicts and deficiencies in work that interfaces cladding protect their ingenuity. Their design is their edge on cost, systems. The characteristics of this surrounding work are the method, time, competition, and risk. This inevitably stifles yradnuob snoitidnoc for the stone cladding system. Control innovation and prevents the current state-of-the-art stone tech- obfo undary conditions avoids engineering unknowns and con- .1