Chapman by wuyunyi

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									 Timber, a truly sustainable resource, can be
used to replace steel and concrete structures
           in multi-storey building.


          John Chapman, Senior Lecturer
          School of Architecture, University of Auckland
 Introduction to recent timber building research -
     School of Architecture, University of Auckland

• pinus radiata timber
  poles as the main
  structural elements in
  commercial / industrial
  building

• research is in response to
  the advantages of timber
  as a sustainable material

• 4 separate, but
  interrelated, studies
Environmental Reasons for radiata
poles as structural elements in building


                         • radiata poles are
                         -   a renewable resource

                         -   require little energy during
                             manufacture

                         -   absorb carbon from the
                             atmosphere and reduce
                             greenhouse gases
 Other Reasons for
radiata poles as building
  structural elements

• Competent
  structural product

• higher failure stresses
  than sawn lumber

• cheap timber at
  NZ$350/cu.m

   –   Images by Andrew Charleson – senior lecturer
       Victoria University
Study 1: Radiata Poles as the Columns
    in Multi-storey Timber Building
Study 2 – Investigating Timber Floor
   Types for Commercial Building

 • floor structure types:
    – glulam
    – timber trusses
    – LVL (linear veneer lumber)

 • office live loading of 3 Kpa

 • resulting timber floors
   compared for cost and
   volumes of timber.
    Study 3: Large
    Industrial Truss
Structures Using Pinus
     Radiata Poles
Study 4: Six Storey Apartment Building
 using Radiata Poles for the Beam and
     Column Structural Elements


 • results of studies 1 to3 led to the
   proposal that timber poles were very
   suited for the structural elements in
   medium storey apartment building
  Apartment Plans

• beams and posts can
  be arranged as simple
  posts and beams


                                  Prototype Pole Building-Plan of Units (figure 1)




• resistance to horizontal
  loads supplied by the
  frequent party walls

• floor is timber
   – floor beams are pairs of   Prototype Pole Building-Plan of Main Structure (figure 5)


     radiata poles
Apartments Cross Section

• The research considered
  seven aspects of the
  prototype pole building

   – dimensional stability of the
     timber

   – environmental impact

   – building strength

   – non destructive testing of
     poles

   – economics

   – fire resistance

   – sound insulation
            Environmental Impact
• Pole building structure
   – Energy for manufacture
               = 0.5 Gj/sq.m.
   – Total carbon absorbed from
     atmosphere
               = 27.4 Kg/sq.m.

• Equivalent RC structure
   – Energy for manufacture
               = 2.24 Gj/sq.m.
   – Total carbon emitted into
     atmosphere
               = 52.5 Kg/sq.m.
          Building Strength

• pole members
  readily available

• for major
  earthquake zones,
  column pole
  diameters increase
  by 50mm approx
      Non Destructive Testing of
            Timber Poles

• Acousto-ultrasonic
  based methods relate
  propagation velocity of
  the longitudinal wave
  with wood density and
  modulus of elasticity

• Acousto-ultrasonic
  testing detects pole
  defects.
                  Economics

• pole/timber structure is 89% the cost of the
  equivalent reinforced concrete structure
  – Pole building structure =   US$124.40 / sq.m.
  – Equivalent R.C.         =   US$208.70 / sq.m.



• timber buildings are significantly lighter than
  the R.C. alternatives and have reductions in
  foundation costs. (not considered in above cost
  analysis)
             Fire Resistance




• each residential unit is an independent fire cell
   – pole structure & party walls are plasterboard lined

• 80mm expected loss of pole diameter in 1 hour
  fire
   – Poles will continue to support building after 1 hour fire
                     Sound Insulation
•   50mm thick concrete floor toppings to protect from vertical noise transference

•   Horizontal insulation at party walls assisted by fibreglass blanket between two
    separated timber frames

•   Sound transference the main obstacle to timber building. Research occurring at the
    University of Auckland Acoustics Research Centre and elsewhere in world
       Conclusions to Radiata Poles as the
      Columns in Multi-storey Timber Building

• no impediments to radiata poles as
  main structural members in multi-
  storey of up to at least 6 storeys

• 6 storey apartment building most
  complete project
   – considered more deeply the
      issues and perceived problems

• Further research into this low
  energy, sustainable, and
  atmosphere assisting building
  product is continuing

								
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