Learning Objectives. Copyright Materials. Timber over non-combustible Podium Structures. High Performance and Low Cost.

Size: px
Start display at page:

Download "Learning Objectives. Copyright Materials. Timber over non-combustible Podium Structures. High Performance and Low Cost."

Transcription

1 Timber over non-combustible Podium Structures High Performance and Low Cost The Wood Products Council is a Registered Provider with The American Institute of Architects Continuing Education Systems The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Scott Nyseth, PE Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Copyright Materials This presentation is protected by US and International Copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited. Learning Objectives At the end of this program, participants will be able to: 1. To examine relevant IBC code provisions applicable to mid-rise podium structures. 2. To discuss the structural design challenges such as lateral load transfer, high vertical loading and effects of shrinkage. 3. To explore the fire and life safety code requirements and the use of fire retardant treated lumber. 4. To identify opportunities for implementation of new products and techniques. The Wood Products Council 2011

2 Five story Timber over Podium Structure Fire and Life Safety Parking Level Meets the definition of a basement, does not contribute to area or height limitation. Ground Floor Type IA Construction Occupancy S2, B, E, A2. Allowable Height - Unlimited Allowable Stories - One Story Allowable Area - Unlimited Podium (2-6) Allowable Height - 55 Allowable Stories - Four Stories Allowable Area - 16,000 sf Type IIIB Construction Occupancy R2 Modifications to height Use automatic sprinkler system to add one story and 20 to allowable height. Modified height Allowance (fire and life safety) = 75 Structural height allowance for plywood shear walls = 65 Both limitations need to be checked

3 IBC Type IIIB details Type III construction is that type of construction in which the exterior walls are of non combustible materials and the interior building elements are of any material permitted by this code. Fire Retardant Treated Wood framing complying with section shall be permitted within exterior wall assemblies of a 2hr rating or less. IBC Tables 601&602 Exterior Bearing Walls 2hr Exterior Non-Bearing Walls 1hr (0hr if building separation>30 ) All other walls, floors, and roofs 0hr The project I visited today was at Bethany Village in NW Portland. What I learned: Fire Retardant treated material looked surprisingly good, even the header stock (so I may stand corrected on previous statement). Due to 25% reduction in structural capacity for FR treated lumber, more studs or heavier columns needed in exterior walls for bearing. (Corrosion, Engineered Lumber Scott) This was Washington County job, but they only required them to take the 2 hr ext wall rating to top of the plate line at the upper floor. The ends of the trusses were not FR treated and they were not installing 2 layers of gyp on the interior side of the truss. The end studs on all walls intersecting the 2 hour ext walls were held back 1 ½ so that 2 layers of drywall could pass through, both top plates were tight to the ext wall. Any beams that intersected the exterior walls were required to have solid blocking inside the wall. 1 st layer of Exterior Dens was tacked on. 2 nd layer was nailed with 2 ½ gun nails thereby eliminating nailing off each layer individually. Approved by structural. I am attaching the 2 hour details used on this project but I think a 3x8 top plate ripped to 7 and cantilevered inside the wall to carry a top flange hanger would work better than this. Floor plywood intersecting the 2 hour walls was not required to be FR treated material. Area separation wall that I observed appeared to be at least 3 hour and was framed with shaft wall both sides with a seismic joint in the middle. All FR treated lumber is marked with a blue paint stripe. When the framers are nailing up the exterior walls they need to make sure the paint is visible from the interior side (for the inspector) Larry Congested Exterior Walls = poor building envelope Consider using corridor walls to resist lateral forces

4 Consider using 3x or 4x studs at 24 oc at shear walls. Use more shear walls to minimize double sided. Avoid 4 walls unless absolutely necessary. Consider 1-1/8 T&G plywood flooring for blocked rigid diaphragm analysis. Continuous Threaded Rod Holdown

5 Window Washing Davit Detail No Cantilevered Wood Balconies! Knife plates below deck for maintenance

6 Be prepared for panelization Brick Veneer supported off Timber Already Fire Retardant Treated Beware of solid sawn rim board Joint often for seismic/wind Joint for floor to floor deflection 1 gypcrete, eco-roof, and brick veneer creates heavy building (more plywood shear walls) Better than 30 of brick off of podium for shrinkage compatibility

7 Prefabrication/Modularization using integrated modeling software Can interface directly with computer controlled fabrication Direct output of materials/order lists High quality and low moisture content High speed of construction. Follow on subs will control critical path. Advanced Framing Alignment Image from Cost Effective Home Building: A Design and Construction Handbook by the NAHB

8 Approximate Lumber Savings Savings Wall Studs Top Plates Trimmers NL Bearing Headers Corners/ Intersections Totals 30,000 BF 23,375 BF 10,800 BF 5250 BF 10,000 BF 80,000 bf Equivalent to about 2.9 acres of 30 year old Douglas Fir Design for deflection! Photo back sloped flashing Advanced Framing = 33% less shrinkage Modified Balloon Framing = no solid sawn rim to shrink On the Structural Plans, put a minimum of 3/16 to a ¼ per floor shrinkage notation. Beware of shrinkage calculations that are significantly less that this. MEP needs to account for deflection. Be cautious of 30 brick veneer supported on podium. Use shrinkage compensating hold down system

9 Calculation of shrinkage is only an estimate and varies greatly How about CLT? Easiest initial commercial market is roofs and floors until AWC incorporates into code (total system is still ok under AM) ~6 floor/roof panels will work in most multi-story apartment and affordable housing projects Eliminates small headers (two way action) Low floor to floor High floor performance Fast installation Typical CLT dimensions: Length: up to 60 Width: up to 15 6 Thickness: from CLT Acoustic Performance Sylvain Gagnon, Eng. February 8, 2011 Vancouver

10 Revolutionary CLT Floor Conventional wood floor Bare CLT Floor Cross-section of a CLT floor Floor Composition Airborne (STC) db Impact (IIC) db 5-layer CLT panel 146 mm FPInnovations. All rights reserved. 10/02/ FPInnovations. All rights reserved. 10/02/2011 Floor Composition 1 Particleboard panel 22 mm 2 Sound insulation material ( 40 mm) 3 Lumber sleepers 4 REGUPOL underlayment 5 5-layer CLT panel 146 mm Airborne Impact (STC) db (IIC) db Floor Composition 1 Gypsum fibre board FERMACELL 25 mm 2 Sub-floor ISOVER EP3 20 mm 3 5-layer CLT panel 135 mm Airborne Impact (STC) db (IIC) db FPInnovations. All rights reserved. 10/02/ FPInnovations. All rights reserved. 10/02/2011

11 Floor Composition 1 5-layer CLT panel 146 mm 2 Resilient supports and rails (100 mm) 3 Sound insulation material (100 mm) 4 Gypsum board 13 mm 5 Gypsum board 13 mm 2009 FPInnovations. All rights reserved. 10/02/2011 Airborne (STC) db Impact (IIC) db Floor Composition 1 Particleboard panel 22 mm 2 Particleboard panel 22 mm 3 Sound insulation material ( 40 mm) 4 Lumber sleepers 5 REGUPOL underlayment 6 5-layer CLT panel 146 mm 7 Resilient supports and rails (100 mm) 8 Sound insulation material (100 mm) 9 Gypsum board 13 mm 10 Gypsum board 13 mm 2009 FPInnovations. All rights reserved. 10/02/2011 Airborne Impact (STC) db (IIC) db Bare CLT Wall Airborne Wall Composition (STC) db 1 3-layer CLT panel (95 mm ~ 115 mm) 32~34 Wall Composition 1 Gypsum board 15 mm 2 3-layer CLT panel (95 mm ~ 115 mm) 3 Gypsum board 15 mm 36~38 Airborne (STC) db 2009 FPInnovations. All rights reserved. 10/02/ FPInnovations. All rights reserved. 10/02/2011

12 Five stories Timber frame over podium: Maximizes density in urban settings Functional, durable, economical, and carbon friendly Modularization, panelization, CLT and advanced framing, are versatile tools for a sustainable natural resource. Wall Composition 1 Gypsum board 15 mm 2 Mineral wool (~ 60 mm) 3 Lumber studs (38 mm x 63 mm) 4 3-layer CLT panel (95 mm ~ 115 mm) 5 Mineral wool (~ 60 mm) 6 Lumber studs (38 mm x 63 mm) 2009 FPInnovations. All rights reserved. 10/02/2011 Copying 7 and redistribution Gypsum prohibited. board 15 mm Airborne (STC) db 58 Questions? This concludes The American Institute of Architects Continuing Education Systems Course Scott Nyseth, PE Stonewood Design LLC scott.nyseth@stonewood-design.co Wood Products Council info@woodworks.org