DOCSLIB.ORG

Connection Options for Wood-Frame and Heavy Timber Buildings

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Connection Options for Wood-Frame and Heavy Timber Buildings Photo: Robert Benson Photography CONTINUING EDUCATION CONTINUING Portland Jetport, Portland, Maine Architect: Gensler Southern pine glulam was chosen for this 40,000-sf roof because of its ability to span long distances with minimal need for intermediate supports. Connection Options for Wood-Frame and Heavy CONTINUING EDUCATION Earn 0.1 ICC Timber Buildings Continuing Effective solutions provide strength, stiffness, Education Credit stability and ductility Learning Objectives Sponsored by reThink Wood After reading this article, you should be able to: he use of wood as a structural extreme events such as hurricanes and 1. Describe the basic categories of material continues to grow far earthquakes. According to post-disaster mechanical and joinery connections beyond traditional applications, such surveys, structural failures during these for modern wood structures, and their T application in both light wood-frame and as single-family homes and buildings up events are often due to faults in connection heavy timber construction. to four stories. Although recent attention design or assembly. 2. Examine the wide range of connection has focused on the possibility of wood This continuing education course options available today, from traditional high-rises, wood’s cost-effectiveness, provides an overview of connection options joinery methods to widely used fasteners versatility and light carbon footprint are for modern wood structures, both light and connectors to the innovative already making it a material of choice for wood-frame and heavy timber (see glossary). proprietary connection systems that are enabling longer wood spans, higher walls an expanding range of building types— It covers mechanical connections—including and taller buildings. from innovative public, educational and dowel, shear and metal connector plates with 3. Apply practical and technical design corporate structures that utilize mass integral teeth—and joinery connections, as guidance to ensure effective performance timber products as their main architectural well as proprietary connections that are in of connections in wood structures. expression, to five-story (and higher) many ways supporting the current surge in 4. Discuss key considerations for selection and installation of connections, for best multi-family projects built with dimension innovative wood design. Proper selection performance and to avoid potential lumber using long-established techniques. and installation, and ways to avoid potential problems. An essential element common to all of these problems, are also discussed. buildings is effective connections. To receive credit, you are required to read In wood buildings, effective connections WOOD CONNECTION BASICS the entire article and pass the quiz. Go to www.awc.org for complete text and to take provide strength, stiffness, stability and To determine the most appropriate the quiz for free. ductility in addition to providing a connection for a given application, continuous load path to the foundation. it is necessary to understand certain They are critical to building performance— fundamentals, starting with the terminology. AWC Course # DES315A-1 ICC Course #7697 under regular loads, and especially during In this continuing education course, CONNECTION OPTIONS FOR WOOD-FRAME AND HEAVY TIMBER BUILDINGS Table 1: Example of Comparative Design Values WOOD BUILDING No. 2 Douglas-Fir Larch 2x or 4x Parallel to Grain Perpendicular to Grain SYSTEMS: A GLOSSARY The terms for different types of wood Compression Design Value (psi*) 775 625 building systems can be confusing, and the way they are used also varies Tension Design Value (psi) 575 No published values slightly in different parts of the world. Following is a brief glossary of terms Dowel Bearing Strength for 5,600 4,450 as they are used in this course: ¼-in.-dia fastener (psi) *Pounds per square inch LIGHT-FRAME WOOD CONSTRUCTION is characterized by vertical and horizontal structural elements formed a connection encompasses all of the or compression perpendicular to grain by a system of repetitive wood framing components that attach one part of a building values. However, dowel bearing strengths members. Framing is made from element to another, be it wood to wood, wood perpendicular to grain are lower relative to standard sizes of 2x and 3x dimension to steel or wood to another material. Within dowel bearing strengths parallel to grain for lumber, and vertical supports are the connection are connectors and/or fasteners. larger diameter (less than ¼ in.) fasteners more numerous than with other wood Metal hangers, column bases and many other (see Table 1). building systems. In addition to low-rise products fall within the category of connectors. buildings, four-story Type V buildings Fasteners include (among others) nails, screws, u Wood is weakest when tension is and five-story Type III buildings timber rivets and bolts. These products do the applied perpendicular to grain. This are commonly light-frame wood ultimate work of fastening the elements of a should be avoided—which is why there construction. connection, either with additional connectors are no published design values for tension (such as hangers) or on their own. perpendicular to grain. MASS TIMBER CONSTRUCTION uses Several characteristics of wood are also large prefabricated wood members relevant to overall connection behavior. Second, wood connections are stronger made from cross laminated timber (CLT) First, wood is anisotropic, meaning it when the load is spread over a number of or structural composite lumber (e.g., has different strength properties in different fasteners. Large concentrated loads should laminated veneer lumber, laminated directions: longitudinal (strong), tangential be avoided unless designed not to exceed the strand lumber, parallel strand lumber) (weaker) and radial (weakest). wood’s strength capabilities (e.g., net tension for wall, floor and roof construction. Nail and shear). Spreading the load also builds in laminated timber, another form of mass u Wood is stronger in compression and a degree of redundancy, which is useful in timber construction, has been utilized tension parallel to grain versus perpendicular high-wind or seismic events. To accomplish for over 20 years. It includes vertical 2x to grain; the former is the preferable way of this, designers are advised to: sawn lumber, nail laminated together to designing wood connections. However, this is create a solid wood floor system.Glued- not always practical or possible. u Use small fasteners (less than ¼ in. dia). laminated timber (glulam) can also be u Use multiple fasteners when possible. used in beam and column applications. u While wood is weaker in compression u Keep the scale of fasteners relative to the perpendicular to grain, this is the most size of wood members being connected. TIMBER-FRAME describes the structural common way to transfer loads in construction. configuration of a broad category of The most common loads are gravity loads, and Third, as with other building materials, systems, including post-frame, post-and- the typical way to transfer them is in bearing— wood moves in response to environmental beam, and heavy timber braced frame. It thus reliance on the compression perpendicular conditions. The main driver for this is characterized by the use of members to grain properties of wood. Fasteners and movement in wood is moisture. Allowances (typically larger than 4×6) arranged in connectors are required to transfer other must be made to accommodate potential two-dimensional frames at a consistent loads, such as wind uplift and the lateral loads shrinkage and swelling, particularly in interval throughout a building. caused by occasional wind and seismic forces connections. (See Moisture Effects on page 6.) to provide a continuous load path to the HEAVY TIMBER relates to fire foundation. CONNECTION TYPES resistance and is specifically defined as a There are two major types of connections construction type—Type IV—within the While capacities are more limited when used in wood buildings: mechanical and 2015 International Building Code (IBC). wood is loaded in compression perpendicular joinery (sometimes referred to as carpentry). Buildings with mass timber and timber- to grain (versus parallel to grain), the limits Within these categories are many variations, frame systems can be used within the for bearing conditions on the surface of and thus a wide range of options to heavy timber category if the minimum wood members are deformation-based, accommodate virtually any building design. sizes specified for Type IV construction not strength-based, and published design are met. values can be increased for smaller bearing Mechanical Connections areas. Accordingly, dowel bearing strengths Mechanical connections used in wood are higher relative to compression parallel buildings can be classified into three major 2 CONNECTION OPTIONS FOR WOOD-FRAME10d ANDNails HEAVY TIMBER BUILDINGS Photos: Josh Partee Photography 10d3 x 0.265 NailsBoat Nail 2-7/8 x 0.120 Sinker Nail 10d3 x 0.265 Nails Boat Nail 2-7/8 x 0.120 Sinker Nail 3 x 0.265 Boat Nail EDUCATION CONTINUING 2-7/8 x 0.120 Sinker Nail 3 x 0.265 Boat Nail 2-7/8 x 0.120 Sinker Nail 3 x 0.265 Boat Nail 2-7/8 x 0.120 Sinker Nail 3 x 0.128 Bright Box Nail 2-7/8 x 0.135 Corker Nail 3 x 0.128 Bright Box Nail 2-7/8 x 0.135 Corker Nail 3 x 0.128 Bright Box Nail 2-7/8 x 0.135 Corker Nail 3 x 0.128 Bright Box Nail 2-7/8 x 0.135 Corker Nail 3 x 0.128 Bright Box Nail 2-7/8 x 0.135 Corker Nail 2-7/8
Load more

Recommended publications
  • TFEC 1-2019 Standard for Design of Timber Frame Structures And
    TFEC 1-2019 Standard for Design of Timber Frame Structures and Commentary TFEC 1-2019 Standard Page 1 January 2019 TFEC 1-2019 Standard for Design of Timber Frame Structures and Commentary Timber Frame Engineering Council Technical Activities Committee (TFEC-TAC) Contributing Authors: Jim DeStefano Jeff Hershberger Tanya Luthi Jaret Lynch Tom Nehil Dick Schmidt, Chair Rick Way Copyright © 2019, All rights reserved. Timber Framers Guild 1106 Harris Avenue, Suite 303 Bellingham, WA 98225 TFEC 1-2019 Standard Page 2 January 2019 Table of Contents 1.0 General Requirements for Structural Design and Construction .......................................6 1.1 Applicability and Scope ........................................................................................ 6 1.2 Liability ................................................................................................................. 6 1.3 General Requirements ........................................................................................... 7 1.3.1 Strength ........................................................................................................... 7 1.3.2 Serviceability ................................................................................................... 7 1.3.3 General Structural Integrity ............................................................................. 7 1.3.4 Conformance with Standards .......................................................................... 7 1.4 Design Loads ........................................................................................................
    [Show full text]
  • Coco Lumber Sawdust
    MushroomPart II. Oyster Growers Mushrooms’ Handbook 1 Chapter 5. Substrate 91 Oyster Mushroom Cultivation Part II. Oyster Mushrooms Chapter 5 Substrate COCO LUMBER SAWDUST J. Christopher D. Custodio Bataan State College, the Philippines Oyster Mushrooms (Pleurotus spp.) are saprophytic as they obtain there nutrients by decomposing various agricultural by-products. This mushroom has been cultivated worldwide because of its taste and low maintenance technology. There are different substrates that have already been identified that can be utilized for the cultivation of oyster mushroom. The possible substrates include rice straw, coffee pulps, sawdust, and even paper. Most of these are types of low-value lignocellulosic wastes that are primarily derived from agricultural practices or the agro-industry. (J.A. Buswell et. al., 1996) The bioconversion of these wastes is one reason why the cultivation of edible mushrooms is an appropriate practice for a society that depends on its agriculture. In the early 1990s, ‘coco lumber’ was given a great attention in the province as a substitute for hardwood. Sawmills producing lumber from coconut trees bloomed in reaction to the increasing demand for this low cost constructional material. Though beginners in mushroom cultivation are usually persuaded not to use sawdust from softwoods, sawdust from coco lumber (Fig. 1) is another possible substrate for P. ostreatus and has shown great results. Growers living near a coco lumber sawmill can make use of this waste product in order to start their own cultivation of oyster mushroom species. Figure 1. Coco lumber sawdust Coco Lumber Sawdust as a Substrate of Oyster Mushroom Oyster mushroom is one example of edible mushrooms that can utilize lignocellulosic materials as a substrate.
    [Show full text]
  • Section 061053 - Miscellaneous Rough Carpentry
    SECTION 061053 - MISCELLANEOUS ROUGH CARPENTRY PART 1 - GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section. 1.2 SUMMARY A. This Section includes the following: 1. Wood framing, blocking, and nailers 2. Wood battens, shims, and furring (for wall panel attachment). 3. Plywood sheathing for miscellaneous structures and replacement of deteriorated roof sheathing. B. Related Sections include the following: 1. Section 075216 "SBS Modified Bituminous Membrane Roofing" for adhesively applied 2-ply, SBS bituminous membrane roofing, with self-adhered base ply sheet. 2. Section 076200 "Sheet Metal Flashing and Trim" for installing sheet metal flashing and trim integral with roofing. 1.3 DEFINITIONS A. Dimension Lumber: Lumber of 2-inches nominal or greater but less than 5-inches nominal in least dimension. B. Lumber grading agencies, and the abbreviations used to reference them, include the following: 1. NLGA: National Lumber Grades Authority. 2. WCLIB: West Coast Lumber Inspection Bureau. 3. WWPA: Western Wood Products Association. 1.4 QUALITY ASSURANCE A. Testing Agency Qualifications: For testing agency providing classification marking for fire- retardant treated material, an inspection agency acceptable to authorities having jurisdiction that periodically performs inspections to verify that the material bearing the classification marking is representative of the material tested. PRSD – Thompson Elementary School Roof Replacement 061053 – MISCELLANEOUS ROUGH CARPENTRY July, 2012 Page 1 of 7 B. Forest Certification: For the following wood products, provide materials produced from wood obtained from forests certified by an FSC-accredited certification body to comply with FSC 1.2, "Principles and Criteria": 1.
    [Show full text]
  • The Wood Lumber Company
    Te Wood Lumber Company by Deborah Grifn Scanlon Tis story starts with Edmund Wood, who owned One hundred and three years later, Falmouth has the Greene and Wood Lumber Yard, a chain of about 32,000 year-round residents, too many lumber warehouses based in New Bedford that dwellings to count, LED streetlights and a 60-per- dated back to 1835. In 1912 Mr. Wood saw son police department. Te Miskells - Joseph’s potential for growth in Falmouth and decided to grandson, Dana Miskell, and his wife Eileen - still open a branch here. He bought James Cameron’s own, manage, and welcome new and old customers small lumber yard on Locust Street and named it to Te Wood Lumber Company. Te Wood Lumber Company. Te lumber business that Edmund Wood bought on Locust Street from Mr. Cameron was originally on King Street. Owned since at least 1875 by B. B. King, for whom the street was named, the business was purchased in 1895 by Mr. Cameron. A native of Scotland, Mr. Cameron came to Fal- mouth by way of Naushon Island, where he was superintendent of the Forbes’s farm. He operated the lumber business on King Street until 1909, when he moved it to Locust Street. Te frst build- ing he put up was a large cypress shed which was in Te frst Wood Lumber Co. ad in Te Enterprise, March use for many years. In 1912, Mr. Cameron sold his 12, 1912 business to Mr. Wood and then lived in Falmouth Joseph B. Miskell, the 22-year-old son of James in retirement for another 25 years.
    [Show full text]
  • Subay Nail Drill Instructions
    Subay Nail Drill Instructions Kelsey often sideswipe disinterestedly when freezing Rex insulating garrulously and cocainises her hijacking. Pryce hybridises her dermatogens deplorably, she muddies it privily. Osbourn is distrustfully shaggy after Tyrian Yard purpled his wampum passing. With minimal noise, and even industry leaders are claimed to resolve, say that bits look great! Her instructions on almost identical, not have a bit you get shiny resistant silicone sleeve, cuts enable an ionic foot. We love this very impressed when they are using. Any underlying medical conditions. Has Your oral Fungus Cleared Up Dallas Podiatry Works. Top 10 Best Electric Nail her in 2021 Reviews Buyer's Guide. The callused areas of calluses usually throw in. Shop Women's Nails at it Red size OS Nail Tools at a discounted price at Poshmark. Use a disinfecting formula that we also sure you do not progressively loaded images displayed are some of colors whether you. It was neatly packaged I resolve the instructions used it stall a low setting to shape. While men on property natural nail keep these drill guide a speed between 2500 and 6000 RPM Anything faster might risk damaging or cracking the gate of your wedding nail in the bit flat above the nail while present are saying Hold your drill but a horizontal position take you file. If you can occur because of healthline media a subay has. The subay has been excellent quality of leather shoes. The instructions on sale it opens your skin on how dangerous or refund service of attachments, vibrations can use with a versatile.
    [Show full text]
  • Environmental Considerations of Treated Wood National Park Service – Pacific West Region
    Environmental Considerations of Treated Wood National Park Service – Pacific West Region Overview In support of the mission of the National Park Service, making wise decisions about using wood treatments will help protect the natural areas and biodiversity of our parks, and the health of our employees. Preservative-treated wood’s most important benefit is its resistance to water, fungal, and insect damage. Extending the life of wood products reduces the demands on forests for replacement lumber and reduces maintenance and replacement costs. Historic wooden structures that must be repaired with compatible materials or replaced with in-kind materials make durability even more important. Treated woods are nearly impervious to rot and insects, making them good for outdoor use. Wood treated with chromated copper arsenate (CCA) poses certain environmental and health risks, including the leaching of chemicals such as arsenic and chromium into the environment and workers’ risk of exposure to hazardous chemicals. Disposal of treated wood also proves to be an issue, particularly disposal by incineration. Due to these concerns, manufacturers of treated wood and the EPA reached an agreement to end the sale of CCA-treated wood for most lumber products, effective January 1, 2004. The following offers less-toxic alternatives to CCA, handling and use precautions, and other recommendations when considering using treated wood. Due to the toxicity and potential effects on health and the environment, the Presidio Trust implemented a policy on the use of pressure treated lumber. Standard operating procedure now prohibits the use of CCA, ACZA, CZC, ACC, and Pentachlorophenol. All dimensional lumber is now treated with ACQ as an alternative.
    [Show full text]
  • UFGS 06 10 00 Rough Carpentry
    ************************************************************************** USACE / NAVFAC / AFCEC / NASA UFGS-06 10 00 (August 2016) Change 2 - 11/18 ------------------------------------ Preparing Activity: NAVFAC Superseding UFGS-06 10 00 (February 2012) UNIFIED FACILITIES GUIDE SPECIFICATIONS References are in agreement with UMRL dated July 2021 ************************************************************************** SECTION TABLE OF CONTENTS DIVISION 06 - WOOD, PLASTICS, AND COMPOSITES SECTION 06 10 00 ROUGH CARPENTRY 08/16, CHG 2: 11/18 PART 1 GENERAL 1.1 REFERENCES 1.2 SUBMITTALS 1.3 DELIVERY AND STORAGE 1.4 GRADING AND MARKING 1.4.1 Lumber 1.4.2 Structural Glued Laminated Timber 1.4.3 Plywood 1.4.4 Structural-Use and OSB Panels 1.4.5 Preservative-Treated Lumber and Plywood 1.4.6 Fire-Retardant Treated Lumber 1.4.7 Hardboard, Gypsum Board, and Fiberboard 1.4.8 Plastic Lumber 1.5 SIZES AND SURFACING 1.6 MOISTURE CONTENT 1.7 PRESERVATIVE TREATMENT 1.7.1 Existing Structures 1.7.2 New Construction 1.8 FIRE-RETARDANT TREATMENT 1.9 QUALITY ASSURANCE 1.9.1 Drawing Requirements 1.9.2 Data Required 1.9.3 Humidity Requirements 1.9.4 Plastic Lumber Performance 1.10 ENVIRONMENTAL REQUIREMENTS 1.11 CERTIFICATIONS 1.11.1 Certified Wood Grades 1.11.2 Certified Sustainably Harvested Wood 1.11.3 Indoor Air Quality Certifications 1.11.3.1 Adhesives and Sealants 1.11.3.2 Composite Wood, Wood Structural Panel and Agrifiber Products SECTION 06 10 00 Page 1 PART 2 PRODUCTS 2.1 MATERIALS 2.1.1 Virgin Lumber 2.1.2 Salvaged Lumber 2.1.3 Recovered Lumber
    [Show full text]
  • Itening Guide
    itening Guide There are three essential tasks involved in the making of any woodwork project. The first is to cut out and shape the components; the second is the joining of those components; and the third and final task is the finishing of the article. This appendix provides you with information about the best ways to fasten your workpieces together, to ensure your project's long life. The options are between adhesives, nails, screws and bolts. NAILS Nailing is a quick, efficient and economical way of joining timber. lf the correct nails are chosen, there is no reason why the joints should not be durable. Timber framed houses, with most of the framing just nailed together, have stood the test of time. The listing of nail types that follows provides an overview of commonly used nails. This listing is not complete - nails exist for specific purposes such as boat-building, but these are outside the requirements of the normal handyman. _ Nail Types: Gommon Bullet Head: Used for hardwood framing and general fixing. Flat Head: Used for softwood framing, fixing softwoods or anywhere bullet heads would tend to pull through. Wire Brads: Small bullet head nails, used for attaching decorative mouldings. Clouts: Small nails with a relatively large flat head, used for attaching thin sheet material. Nail Types: Special Purpose Tacks: Used principally for upholstery; commonly blue- black in colour. Panel Pins: Used for fixing plywood panelling to timber framing; "brown" plated. Hardboard Nails: Used to attach hardboard ("masonite"); generally zinc plated. Plaster Board Used for fixing plasterboard to timber framing; Nails: zinc plated.
    [Show full text]
  • Wood Preservation: Improvement of Mechanical Properties by Vacuum Pressure Process
    International Journal of Engineering and Applied Sciences (IJEAS) ISSN: 2394-3661, Volume-2, Issue-4, April 2015 Wood Preservation: Improvement of Mechanical Properties by Vacuum Pressure Process Md. Fazle Rabbi, Md. Mahmudul Islam, A.N.M. Mizanur Rahman timber. The amount of damage by the second is negligible in comparison to the first enemies. By applying proper Abstract— Wood, being a biological product, is liable to preservation technique, it is possible to protect the timber deterioration unless it is properly protected. The main reasons of deterioration of timber in service are decay due to fungal from these enemies. Preservation is the only appropriate way infection, attack by insects (borers and white ants), marine to make the timber toxic and protect it [1]. organisms and fire. Protection of wood is carried out from these agents by using preservative which can properly be used by proper design of preservation plant. Proper design of such plant The primary importance of the preservation treatment of is very essential to increase the lifespan of wood economically. wood is to increase the life of the material in service, thus Among the various wood preservation techniques, pressure decreasing the ultimate cost of the product and avoiding the processes are the most permanent technique around the world need for frequent replacements [2]. The extension of the today. In the Full cell process, wood is allowed to absorb as much liquid chemicals as possible during the pressure period, service life of timber by the application of appropriate thus leaving the maximum concentration of preservatives in the preservatives has another significant effect in the field of treated area.
    [Show full text]
  • 06 10 00 --- Rough Carpentry
    DESIGN AND CONSTRUCTION GUIDELINES AND STANDARDS DIVISION 6 WOODS & PLASTICS 06 10 00 • ROUGH CARPENTRY SECTION INCLUDES Dimensional Wood Framing Sheathing Prefabricated Trusses Wood Blocking Engineered Wood Framing Termite Shield RELATED SECTIONS 03 30 00 Concrete 06 20 00 Finish Carpentry 06 50 00 Structural Plastics & Composites 06 65 00 Plastic and Composite Trim 07 62 00 Sheet Metal Trim & Flashing ABBREVIATIONS-TESTING, CERTIFYING AND GRADING AGENCIES AITC- American Institute of Timber Construction www.aitc-glulam.org ALSC- American Lumber Standards Committee www.alsc.org ANSI- American National Standards Institute www.ansi.org APA- The Engineered Wood Association, (formerly American Plywood Association) www.apawood.org AWPA- American Wood Protection Association www.awpa.com CSA- Canadian Standards Association www.csa.ca FSC- Forest Stewardship Council www.fscus.org NIST- National Institute for Standards and Technology www.nist.gov SFI-Sustainable Forest Initiative www.sfiprogram.org TPI- Truss Plate Institute www.tpint.org LOAD CALCULATIONS DESIGN Calculate loads and specify the fiber stress for lumber. Avoid over-designing that will result in unnecessarily high material costs. Spruce, Pine or Fir should be adequate for most conditions; provide a rationale for any other species. ENVIRONMENTAL ISSUES PRODUCTS Use of wood from well-managed forests is preferred. Specify one or more of the following standards: Forest Stewardship Council (FSC); Sustainable Forest Initiative (SFI); or Canadian Standards Association (CSA). Using certified wood encourages a well-managed forest industry. Look for engineered wood products with certified wood content, recycled or recovered wood, and/or products that are produced within 500 miles of the project site. The use of engineered wood should be evaluated on R 06 10 00 ROUGH CARPENTRY……….
    [Show full text]
  • Wood Properties of Teak (Tectona Grandis) from a Mature Unmanaged Stand in East Timor
    J Wood Sci (2011) 57:171–178 © The Japan Wood Research Society 2011 DOI 10.1007/s10086-010-1164-8 ORIGINAL ARTICLE Isabel Miranda · Vicelina Sousa · Helena Pereira Wood properties of teak (Tectona grandis) from a mature unmanaged stand in East Timor Received: May 5, 2010 / Accepted: November 5, 2010 / Published online: March 17, 2011 Abstract The wood quality from 50- to 70-year-old Tectona carpentry. Teak wood is moderately hard and heavy, seasons grandis trees from an unmanaged forest in East Timor was rapidly, kiln dries well, and has overall good machining prop- assessed. The aim was to evaluate teak in mature stands that erties. It is prized mostly for its natural durability and high had undergone uncontrolled disturbances, e.g., fi re and local dimensional stability in association with pleasant aesthetics. community usage. Heartwood represented 91% of the tree Some end-user requirements include high heartwood content radius at a height of 1.7 m, and sapwood contained on average (at least 85%) and wood density (> 675 kg/m3) and suffi cient nine rings. The mean ring width showed within-tree and strength [modulus of rupture (MOR) > 135 N/mm2].1 between-tree variability. The chemical compositions of heart- Teak grows naturally in Southeast Asia and was intro- wood and sapwood were similar. Within-tree chemical varia- duced into other tropical and subtropical regions in Austra- tion occurred only in terms of extractives, which increased lia, Africa, and Latin America. Teak is now one of the most from the pith (8.3%) to the heartwood–sapwood transition important species for tropical plantation forestry, mostly (12.7%) and decreased in the sapwood (9.2%).
    [Show full text]
  • Tall Wood Buildings in the 2021 IBC up to 18 Stories of Mass Timber
    Tall Wood Buildings in the 2021 IBC Up to 18 Stories of Mass Timber Scott Breneman, PhD, SE, WoodWorks – Wood Products Council • Matt Timmers, SE, John A. Martin & Associates • Dennis Richardson, PE, CBO, CASp, American Wood Council In January 2019, the International Code Council (ICC) approved a set of proposals to allow tall wood buildings as part of the 2021 International Building Code (IBC). Based on these proposals, the 2021 IBC will include three new construction types—Type IV-A, IV-B and IV-C—allowing the use of mass timber or noncombustible materials. These new types are based on the previous Heavy Timber construction type (renamed Type IV-HT) but with additional fire-resistance ratings and levels of required noncombustible protection. The code will include provisions for up to 18 stories of Type IV-A construction for Business and Residential Occupancies. Based on information first published in the Structural Engineers Association of California (SEAOC) 2018 Conference Proceedings, this paper summarizes the background to these proposals, technical research that supported their adoption, and resulting changes to the IBC and product-specific standards. Background: ICC Tall Wood Building Ad Hoc Committee Over the past 10 years, there has been a growing interest in tall buildings constructed from mass timber materials (Breneman 2013, Timmers 2015). Around the world there are now dozens of timber buildings constructed above eight stories tall. Some international examples include: Building Completion Location Stories Name Date Stadhaus
    [Show full text]