Wfcm Guide
Read WFCM110-B-Guide.pdf text version 110 MPH EXPOSURE B GUIDE WFCM WOOD FRAME CONSTRUCTION MANUAL GUIDE TO WOOD CONSTRUCTION IN HIGH WIND AREAS FOR ONE- AND TWO-FAMILY DWELLINGS A F & P A® American Forest & Paper Association American Wood Council In Cooperation with the International Code Council® ® Updates and Errata While every precaution has been taken to ensure the accuracy of this document, errors may have occurred during development. Updates or Errata for the WFCM Guide are posted to the American Wood Council website at www.awc.org. Technical inquiries may be addressed to 110 MPH EXPOSURE B WFCM WOOD FRAME CONSTRUCTION MANUAL GUIDE TO WOOD CONSTRUCTION IN HIGH WIND AREAS FOR ONE- AND TWO-FAMILY DWELLINGS Copyright © 2006 American Forest & Paper Association, Inc. GUIDE Guide to Wood Construction in High Wind Areas for One- and Two-Family Dwellings 110 mph Exposure B Wind Zone, 2006 Edition First Printing: October 2006 ISBN 0-9786245-1-3 Copyright © 2006 by American Forest & Paper Association, Inc. All rights reserved.
No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including, without limitation, electronic, optical, or mechanical means (by way of example and not limitation, photocopying, or recording by or in an information storage retrieval system) without express written permission of the American Forest & Paper Association, Inc. For information on permission to copy material, please contact: Copyright Permission AF&PA American Wood Council 1111 Nineteenth St., NW, Suite 800 Washington, DC 20036 email: Printed in the United States of America 110 1 1.1 1.2 Guide to Wood ConstruCtion in HiGH Wind AreAs 110 MPH eXPosure B Wind Zone Table of Contents introduCtion. 1 GenerAL ProVisions. 3 sCoPe. 3 Design Concepts. 3 APPLiCABiLitY.
5 Building Height. 5 Building Dimension. 5 Building Shape. 5 1.3 FrAMinG ConneCtions. 6 2 FoundAtion AnCHorAGe.
8 2.1 2.2 2.3 GenerAL LoAds. 8 AnCHor BoLts. 8 AnCHorAGe At oPeninGs. 9 3 FLoors. 10 3.1 3.2 3.3 3.4 3.5 3.6 GenerAL. 10 Wood FLoor Joist sYsteMs. 10 Wood i-Joists FLoor sYsteMs.
11 Wood FLoor truss sYsteMs. 11 FLoor sHeAtHinG. 11 FLoor BrACinG. 11 4 WALLs. 12 4.1 4.2 4.3 GenerAL.
12 eXterior WALLs. 12 eXterior WALL sHeAtHinG. 17 5 rooFs. 20 5.1 5.2 5.3 5.4 5.5 5.6 GenerAL. 20 Wood rAFter sYsteMs. 20 Wood i-Joist rooF sYsteMs.
23 Wood rooF truss sYsteMs. 23 rooF sHeAtHinG. 23 rooF BrACinG endWALL.
23 GLossArY oF terMs. 24 CHeCKList. 27 AMERICAN FOREST & PAPER ASSOCIATION tA B L e o F C o n t e n t s 110 MPH eXPosure B Wind Zone tABLes 110 Table 1. FiGures Maximum Building Lengths for Permitted Building Aspect Ratios.
6 General Nailing Schedule. 7 Foundation Anchorage Loads. 8 Anchor Bolt Spacing. 8 Exterior Wall - Wood Studs. 12 Top Plate Splice.
13 Wall Connections at Loadbearing Walls. 14 Wall Connections for Endwall Assemblies. 15 Wall Openings Headers in Loadbearing and Non-Loadbearing Walls.16-17 Percentage of Full-Height Sheathing in Minimum Building Dimension (W).
18 Percentage of Full-Height Sheathing in Maximum Building Dimension (L). 19 Truss, I-Joist, or Rafter Connections at Loadbearing Walls. 21 Ridge Strap Connections. 22 Outlooker Connections at Gravity Non-Loadbearing Walls.
Master Building Frame. 4 Mean Roof Height (MRH). 5 Inscribed Building Dimensions. 5 Building Aspect Ratios. 6 Anchor Bolts Resisting Uplift, Lateral, and Shear Loads. 9 Floor Diaphragm Opening Limits. 10 Setback Limits for Loadbearing Wall or Shear Wall and Limit on Loadbearing Wall Offset from Support.
10 Cantilever with Loadbearing Wall or Shear Wall. 11 Floor Bracing. 11 Maximum Wall Height and Stud Spacing. 12 Ceiling Bracing Gable Endwall. 13 Top Plate Intersection Detail.
13 Top Plate Splice Length. 13 Story-To-Story Uplift and Lateral Connections. 14 Full-Height Gable Endwall Stud. 15 Rake Truss. 15 Studs and Headers Around Wall Openings. 16 Corner Stud Hold Down Detail 3 Studs With Blocking. 18 Corner Stud Hold Down Detail 4 Studs.
19 Roof Systems. 20 Rafter Outlooker Details. 22 AMERICAN WOOD COUNCIL 110 Guide to Wood ConstruCtion in HiGH Wind AreAs 110 MPH eXPosure B Wind Zone 1 Introduction The purpose of this Guide to Wood Construction in High Wind Areas: 110 MPH Exposure B Wind Zone (Guide) is to simplify the construction and design of wood frame buildings in areas where design wind velocity requirements do not exceed 110 miles per hour Exposure Category B. This Guide is in compliance with the building code-referenced ANSI/AF&PA 2001 Wood Frame Construction Manual (WFCM) for One- and Two-Family Dwellings. Accordingly, any designs in compliance with this Guide should also be in full compliance with the WFCM. The provisions of this Guide focus on ensuring structural integrity for resisting wind loads.
This Guide does not specifically address other loading conditions such as those created by live, seismic (earthquake), snow, or flood loads. These additional loading conditions must be considered as required by the building code and are addressed in the WFCM. The information in this Guide offers information to architects, builders, designers, code officials, instructors and others interested in simplified design.
It is not the intent of this Guide to instruct on all aspects or techniques of proper framing or design. In developing the provisions of this Guide using provisions of the WFCM, the most reliable data available from laboratory tests and experience with structures in service have been carefully analyzed and evaluated for the purpose of providing a consistent standard of practice. It is intended that this document be used in conjunction with competent engineering design, accurate fabrication, and adequate supervision of construction. Therefore, AF&PA does not assume any responsibility for errors or omissions in this Guide, the WFCM, nor for engineering designs or plans prepared from it. AMERICAN FOREST & PAPER ASSOCIATION 2 GenerAL ProVisions 110 MPH eXPosure B Wind Zone 110 This page left blank intentionally. AMERICAN WOOD COUNCIL 110 1.1 sCoPe Guide to Wood ConstruCtion in HiGH Wind AreAs 110 MPH eXPosure B Wind Zone 3 1 General Provisions This Guide to Wood Construction in High Wind Areas: 110 MPH Exposure B Wind Zone (Guide) establishes a specific set of prescriptive, wind-resistive structural requirements for one- and two-family wood-frame residential buildings of sizes and shapes specified in the 'Applicability' section (1.2) of this chapter.
The provisions of this Guide are directed toward ensuring structural integrity for resisting wind loads. In addition, provisions of this Guide are derived from the wind provisions found in the ANSI/AF&PA 2001 Wood Frame Construction Manual (WFCM) for One- and Two-Family Dwellings. Wind load requirements of this Guide are based on 110 mile per hour, 3-second-gust wind speeds for Exposure B locations. Buildings located in Exposure C shall be designed in accordance with the WFCM.
Structural elements not complying with the conditions contained in this Guide shall be designed in accordance with the WFCM or the governing building code. The provisions of this Guide are not intended to preclude the use of other materials or methods of construction. When alternative methods or materials are used, design loads and capacities shall be determined in accordance with the WFCM or the governing building code. Tabulated values in this Guide shall be permitted to be interpolated unless otherwise noted in the applicable table footnotes. Desgn Concepts 1 GenerAL ProVisions This Guide relies on the following concepts: n Roofs, ceilings and floors are designed as diaphragms, which receive lateral loads from roof and exterior walls (assuming the wind blowing from any direction) and transfer these loads to shear walls. N Exterior walls are designed to resist wind forces and transfer the lateral forces to diaphragms. Exterior walls, foundations, and connections shall be designed to resist lateral and uplift loads received from the roof by means of a continuous load path.
Exterior walls are designed to resist wind loads assuming flexible finishes. N Except for openings, exterior walls are designed as entirely sheathed with wood structural panels or structural fiberboard panels, including areas above and/or below openings. N Openings shall not exceed nominal 6'-8' in height. O Exception: Opening heights of up to 8' shall be permitted when 5% is added to the percent full-height sheathing requirements in Tables 10 and 11 (See pages 18 and 19).
N The tabulated wind requirements in this document are based on fully enclosed buildings where openings are designed for the appropriate wind loads. Where required by the governing building code, protection of openings shall be provided to maintain a fully enclosed building envelope. N The foundation provisions specified in this Guide are limited to the attachment of the building to the foundation.
An adequate foundation system shall be provided to resist all required loads. Engineered and prescriptive design of the foundation for gravity, lateral, and uplift loads, including uplift and hold down anchorage, shall be provided in accordance with the governing building code. AMERICAN FOREST & PAPER ASSOCIATION 4 GenerAL ProVisions 110 MPH eXPosure B Wind Zone 110 note Continuous Load Path.
Wfcm 100 Mph Guide
The interconnection of all framing elements is critical to a windresistive building. A continuous load path of interconnected framing elements from footings and foundation walls to floors, walls, and roof framing shall be provided. Master Building Frame (For Illustrative Purposes Only) AMERICAN WOOD COUNCIL 110 1.2 Guide to Wood ConstruCtion in HiGH Wind AreAs 110 MPH eXPosure B Wind Zone 5 APPLiCABiLitY Buldng Heght The building shall not exceed two stories or a mean roof height of 33 feet, measured from average grade to average roof elevation (See Figure 2). For purposes of determining uplift and lateral bracing requirements, the roof shall be considered an additional story when the roof slope exceeds 6 in 12. The maximum roof slope is 12 in 12. Buldng dmenson 1 GenerAL ProVisions Figure 2.
Wfcm Exposure C
Mean Roof Height (MRH) n The maximum building dimension (L) shall not be greater than 80 feet. N The minimum building dimension (W) shall not be greater than 80 feet.
N The maximum span (horizontal projection) of the roof trusses or rafters covered under the scope of this Guide are limited to 36 feet; however, combinations of these systems can be used for a total inscribed dimension of 80 feet. Buldng shape n Rectangular Buildings. Design provisions in this Guide assume that buildings are rectangular in shape. Walls shall be permitted to be offset by a maximum of 4 ft. (such as projecting bays, inset porches, or other irregular shapes) without requiring detailing.
N Non-rectangular Buildings. In this Guide, non-rectangular buildings are designed as a rectangular building with dimensions that inscribe the nonrectangular building for purposes of determining lateral resistance requirements (See Figure 3).
O Aspect ratios for these buildings shall be calculated as shown in Table 1 (page 6) and Figure 4. O The longest inscribed building dimension shall be assumed to be the building length, L, and the shortest inscribed building dimension shall be assumed to be the building width, W. O The required length of full-height exterior sheathing in Section 4.3 is to be distributed in each wall line segment in proportion to the segment length divided by the overall building dimension. Hold downs shall be placed at each end of wall line segments.
O For conditions where non-rectangular buildings must be designed as separate structures joined at common walls, the WFCM should be used. Inscribed Building Dimensions AMERICAN FOREST & PAPER ASSOCIATION 6 GenerAL ProVisions 110 MPH eXPosure B Wind Zone 110 Figure 4. Building Aspect Ratios Table 1.