Christchurch City Council Draft Central City Plan - Volumes 1 & 2 16 September 2011
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Cement & Concrete Association
of New Zealand
Submission to the
Christchurch City
Council
on
Draft Central City Plan
Volumes 1 & 2
16 September 2011
16 September 2011 Central City Plan Comments Christchurch City Council PO Box 73001 CHRISTCHURCH 8154 Email: centralcityplan@ccc.govt.nz Dear Sir/Madam Re: Draft Christchurch City Plan The Cement and Concrete Association of New Zealand (CCANZ) represents a membership in excess of 300 corporates and individuals who collectively account for a significant proportion of the building and construction sector in New Zealand. The cement and concrete industry annually produces and uses about 1.5 million tonnes of cement in New Zealand, which equates to around 3.75 million cubic metres of concrete for new residential, non-residential and commercial construction. In total, the direct, indirect and induced economic impact of the cement and concrete industry resulted in close to $7.5 billion of output across the economy in the year to March 2006. This activity supported more than 24,000 jobs and created a value add of about $2.8 billion – around 2 percent of New Zealand’s GDP in 2006. In line with our mandate as representative of the cement and concrete industry, CCANZ has prepared the following comments in response to the Christchurch City Council’s draft Christchurch City Plan. Yours faithfully Rob Gaimster CHIEF EXECUTIVE OFFICER 2|P a g e
Contents
INTRODUCTION ...................................................................................................................... 5
GREEN CITY ........................................................................................................................... 5
Eco Streets (page 41) ........................................................................................................... 5
Pervious Concrete............................................................................................................. 6
Concrete Block Permeable Paving (CBPP) / Concrete Grid Blocks (CGB) ...................... 6
Greening the Roof (page 42) ................................................................................................ 7
Green Roofs ...................................................................................................................... 7
Green Walls ...................................................................................................................... 7
District Heating (page 42) ..................................................................................................... 8
Passive Solar Design ........................................................................................................ 9
Green Technologies (page 43) ........................................................................................... 10
Green Star Rating Scheme ............................................................................................. 10
DISTINCTIVE CITY ................................................................................................................ 10
Strong and Resilient Buildings (page 50) ........................................................................... 11
PREcast Seismic Structural Systems (PRESSS) ........................................................... 11
Base Isolation.................................................................................................................. 12
Adaptive Reuse and Strengthening (page 53).................................................................... 12
Adaptive Reuse ............................................................................................................... 12
Strengthening .................................................................................................................. 13
Retention and Reuse of Materials (page 54) ...................................................................... 14
Height and Human Scale (page 55) ................................................................................... 14
CITY LIFE............................................................................................................................... 15
Beneath Ground Structures ............................................................................................ 15
Affordable Housing (page 81) ............................................................................................. 16
Sound Control ................................................................................................................. 16
Housing Showcase (page 82)............................................................................................. 17
TRANSPORT CHOICE .......................................................................................................... 17
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MARKET CITY ....................................................................................................................... 19 DRAFT CENTRAL CITY PLAN VOLUME II-REGULATORY FRAMEWORK ........................ 20 General Comment .............................................................................................................. 20 Clause 6.2.1 Noise Residential activities ............................................................................ 20 Clause 3.11.2 The Build Green Christchurch Tool (Pages 207-212) ................................. 20 Changes to the Global Stormwater Consent requirements (Page 213) ............................. 20 Appendix A - Concrete magazine - Pervious Concrete .......................................................... 21 Appendix B - CCANZ Designing Comfortable Homes ........................................................... 22 4|P a g e
INTRODUCTION The members of CCANZ are passionate about the sustainable development of Christchurch and the broader Canterbury region to ensure a vibrant, economic, social and environmental fabric flourishes in the years ahead. CCANZ is committed to providing whatever assistance it can in the re-build of this important City. In addition, the concrete industry has the local capacity to supply the concrete and concrete masonry demand of the city now and into the future. The region has a strong affiliation to concrete as a sustainable material of choice in the built environment, and world leading reinforced concrete design solutions have been and are continuing to be developed at the University of Canterbury. CCANZ is supportive of the redevelopment of Christchurch and the notion that “Our Central City will be strong, vibrant and prosperous, at the heart of a 21st century Christchurch”. The 2010 and 2011 seismic events provide a unique opportunity to develop innovative urban design and construction excellence to deliver the concept of a city within a garden. Concrete clearly has an important role to play. CCANZ notes the draft Central City Plan features numerous projects which are anticipated to cost $1.9 billion. This submission does not comment on each project but focuses on a number of specific issues. The submission does however, seek specific amendments and in doing so comments have been made under the headings of the draft’s five key initiatives. Comments relating to specific aspects associated with Volume II are included towards the end of the submission. The value of concrete to the five key initiatives has been highlighted as appropriate. GREEN CITY CCANZ supports the GREEN CITY initiative. As New Zealand’s ‘Garden City’ any plan to rebuild Christchurch must place an emphasis on fostering and integrating the natural environment within the urban landscape. In order to realise this vision and celebrate Christchurch as a modern and resilient city with a clear commitment to environmental sensibility, landscape and building design must utilise the best in construction material technology. Locally produced, recyclable concrete and concrete masonry lends itself well to low-impact, resource efficient and sustainable urban design across buildings, greenway networks and infrastructure. As such, the concrete-based construction technologies and systems outlined below must be given serious consideration in any design for a Green City. Eco Streets (page 41) Key to the realisation of eco streets as a means to improve the Avon River/ Ōtakaro corridor and the water / environmental quality of the Central City are three concrete based pavement technologies - pervious concrete, concrete block permeable paving and concrete grid blocks. 5|P a g e
In conventional pavements, rainwater is allowed to run across the surface to gutters that
collect and direct it into pipes, removing it as quickly as possible. This means that water,
along with any pollutants are rapidly conveyed into overloaded drains, streams and rivers,
leading to floods in extreme conditions. Pervious concrete, concrete block permeable paving
and concrete grid blocks offer alternative, sustainable drainage (and pavement) systems that
are available in an extensive range of configurations, colours and shapes.
Pervious Concrete
Pervious concrete can be used to create a structural pavement, which through an
interconnected network of voids, drains and filters stormwater - thereby reducing
runoff and replenishing groundwater supplies. Through cationic exchange, pervious
pavements trap the pollutants and heavy metals associated with stormwater run-off.
A new installation at the Arizona State
University Art Museum is not in a
gallery but is its parking lot, which has
recently been redesigned to
showcase a state-of-the-art
environmentally-friendly alternative to
conventional pavements.
The featured attraction is pervious
concrete.
The proper utilization of pervious concrete is a recognized Best Management Practice
by the U.S. Environmental Protection Agency (EPA) for providing first flush pollution
control and stormwater management.
Pervious concrete is a low maintenance, quick to install and cost effective pavement
system, ideal for car parking areas, as well as foot and cycle paths. It has been
successfully trialled on Auckland’s North Shore (see pages 18-31 of Appendix A.).
Concrete Block Permeable Paving (CBPP) / Concrete Grid Blocks (CGB)
As drainage and pavement systems CBPP & CGB address both flooding and
pollution issues. CBPP & CGB allow water to pass through the surface – between /
within each block – and into the underlying permeable sub-base where it is stored
and released slowly, either into the ground or to a drainage system.
Examples of
Concrete Block
Permeable
Paving and
Concrete Grid
Blocks
6|P a g e
Unlike conventional pavement constructions, the permeable sub-base aggregate is
specifically designed to accommodate water. At the same time, many pollutants are
removed and treated, before water infiltrates to the subgrade (ground) or passes into
the next stage of the management train.
CBPP & CGB variants are already used throughout New Zealand, across
commercial, residential and industrial applications.
Greening the Roof (page 42)
The aesthetic and environmental benefits afforded through green roofs and walls are ideally
suited to enhancing a rebuilt Christchurch.
To allow plants grown up or on buildings to absorb summer heat, reduce the cost of air-
conditioning, improve air quality, as well as act as bio-filters and provide habitat for native
birds and insects, urban designers need look no further than the strength, durability and
design flexibility offered by concrete.
Green Roofs
Leading the way in ecologically sustainable design, Wollaston Estates winery near
Nelson, the NZI Building in Auckland, and Conservation House in Wellington all
exploit the structural and aesthetical potential of concrete to realise unique green roof
features.
Green Walls
The recently completed Hobsonville Motorway Extension near Auckland makes
extensive use of large precast concrete panels containing holes for plants to grow
through. These green walls provide retaining capabilities and a vertical canvas for
natural beatification.
As illustrated, there are numerous and inspiring overseas examples of green roofs and walls.
Example of green roofs from Fukuoka in Japan
7|P a g e
Green concrete roof at the School of Art, Design and Roof terraces on apartments in London
Media in Singapore
Translucent, perforated concrete in a
courtyard and a roof garden application
Cantilevering concrete balconies - The Urban Cactus study for
Rotterdam by UCX Architects
District Heating (page 42)
As the world begins to exhaust supplies of fossil fuels, as well as suffer the consequences of
their continued use, all efforts to explore renewable sources of energy are imperative.
8|P a g e
This exploration, however, should not be restricted solely to agricultural and forestry by-
products, industrial sludges, sewage and landfill gas, wood waste from the demolition of
quake damaged buildings and solar energy captured through photovoltaic panels.
Design experts must give adequate consideration to the potential of passive solar design to
meet a significant amount of residential and commercial buildings’ energy requirements (see
Appendix B.).
Passive Solar Design
A key component of passive solar design is to exploit the mass of heavy building
materials, such as exposed concrete floors and walls, in conjunction with the sun’s
changing elevation angle during the year.
The sun’s heat energy is captured by the
thermal mass of an exposed concrete floor
and concrete masonry walls.
By using concrete’s high mass together with the heat of the sun - or solar energy -
more comfortable living conditions can be achieved with reduced reliance on space
heating or cooling, and subsequent reduced energy demands.
An exposed, well-insulated concrete floor or wall has the capability to absorb, store
and later radiate the sun’s heat, off-setting temperature troughs and peaks, to create
a moderate living environment.
Employing the thermal mass of concrete can help to reduce or even eradicate the
need for energy-intensive heating and cooling devices, while maintaining a
comfortable temperature for occupants.
To optimise a concrete floor’s thermal mass, it must be used in conjunction with
appropriate thermal insulation, window placement for good solar gains and natural
ventilation as part of an integrated and sustainable passive solar design.
The benefits afforded by integrating concrete’s thermal mass into an overall passive
design are clearly evident in the Beacon Waitakere NOW Home®. After two years of
occupancy results are extremely encouraging, with a comfortable interior living
environment being achieved along with reduced energy use.
9|P a g e
Green Technologies (page 43)
The encouragement of green buildings in the Central City through leadership, incentives,
best practice demonstrations, standards and building assessment tools is to be commended.
Amongst modern construction materials concrete is unique in that it provides a complete
range of social, economic and environmental benefits, which when optimised through best
practice design and construction help to secure a lasting and positive legacy for the future.
Major efficiencies and innovations in the manufacture of cement and the production of
concrete have been achieved over the past decades in New Zealand, while the CO2
absorption capabilities of concrete are beginning to be fully understood. The reuse of
concrete structural elements is becoming more commonplace, along with the recycling of
concrete as aggregate. Furthermore, concrete’s durability, thermal efficiency, acoustic
performance, fire resistance, and roading and stormwater applications, ensure that its
contribution to a sustainable construction industry, and in turn built environment, continues to
be significant.
Green Star Rating Scheme
CCANZ supports the New Zealand Green Building Council’s (NZGBC) existing Green
Star rating scheme, and was actively involved in its development, and continues to
offer on-going support. As such, CCANZ also welcomes the creation of a
Christchurch –focussed NZGBC rating tool to encourage holistic design and to
improve the environmental performance of new buildings.
CCANZ believes that such market driven rating schemes provide an appropriate
mechanism for assessing the distinct performance advantages of different building
materials. CCANZ also believes such schemes assist to ensure balanced advocacy
of a building material’s sustainability credentials, as well as resist any moves to go
beyond fair evidence-based commentary and into opportunistic competitive bias.
However, it is impractical for CCANZ to comment on the proposed tool as presented
as it appears that the assessment criteria have yet to developed.
DISTINCTIVE CITY
CCANZ supports the DISTINCTIVE CITY initiative.
Before the events of 22 February 2011 Christchurch city centre stood proud as one of New
Zealand’s most unique cities. Through the adoption of appropriate and sympathetic urban
design principles, which utilise construction materials in the most suitable fit-for-purpose
manner, there is no reason why the city cannot regain a similar standing.
Recent advancements in damage avoidance design systems for concrete buildings will play
an important role in making possible strong and resilient buildings that exceed the New
Zealand Building Code’s (NZBC) seismic requirements, and in turn help produce a high-
quality built environment. In addition, existing concrete elements are suitable for adaptive
reuse, heritage buildings can be sensitively strengthened and their facades retained using
concrete, while demolition concrete can be recycled as aggregate. These factors combine to
10 | P a g edemonstrate that concrete-based construction technologies and systems, as outlined below,
should be considered in any design for a Distinctive City.
However, while CCANZ appreciates the rationale behind the proposed low-rise 7-storey
building limit as a means to help create a distinctive urban landscape that also makes people
feel safe, any restrictions on design parameters will ultimately inhibit the renewal process
and possibly disadvantage Christchurch in the long-term.
Strong and Resilient Buildings (page 50)
Despite perceptions to the contrary within Canterbury, the vast majority of concrete buildings
performed exceptionally well during the 22 February 2011 earthquake. Although the
Canterbury Television and Pyne Gould Corporation buildings failed with significant loss of
life, the collective opinion of the New Zealand engineering community is that these failures
resulted from historical design and codes issues, rather than construction material
deficiencies.
CCANZ fully supports the work of the Royal Commission of Inquiry into Building Failure
Caused by the Canterbury Earthquakes, as well as the Department of Building and Housing
technical investigation into the performance of the Canterbury Television, Pyne Gould
Corporation, Forsyth Barr and Hotel Grand Chancellor buildings.
It is anticipated that a likely outcome of these formal processes will be substantial
amendments to the best-practice requirements for the design, construction and maintenance
of buildings in central business districts throughout New Zealand. At the forefront to meet this
inevitable tightening of seismic code specifications will be damage avoidance design
systems for buildings based on concrete technology, specifically PREcast Seismic Structural
Systems (PRESSS) and Base Isolation.
Both these systems have been proven in practice during the Canterbury earthquakes, with
the Southern Cross Hospital Endoscopy Building, an example of PRESSS, and Christchurch
Women’s Hospital, an example of Base Isolation, both emerging unscathed and immediately
available for reoccupation and use as emergency medical facilities following the 22 February
2011 quake.
PRESSS and Base Isolation, as damage avoidance design systems based on concrete
technology, represent an assured way forward for multi-storey construction in seismic
regions such as Canterbury. By enabling rapid and economic construction, while also
delivering optimal seismic performance that minimises business interruption in the event of
an earthquake, these systems will play a crucial role in allowing Christchurch to fulfil its social
and environmental objectives, while also meeting economic targets that are more achievable
through the commercial viability of multi-storey construction.
PREcast Seismic Structural Systems (PRESSS)
PRESSS uses un-bonded post tensioning cables and rocking joints within a precast
wall, beam and column structure to ensure the building returns to upright without
significant structural damage, even after a major seismic event. Specifically, the
PRESSS system reduces displacements under small earthquakes through its high,
pre-rocking stiffness, while for larger seismic events potential damage is concentrated
towards replaceable energy dissipaters, rather than throughout the structure.
11 | P a g eUnbonded post-tensioning provides the spring action. The joints between beams and
columns, and the shear walls at the ground, rock. The post-tensioning acts to clamp
these joints closed and hence spring the building back to vertical. The shock
absorbers, in this case controlled yielding reinforcing bars, provide damping.
Joints of beams and columns
of a PRESSS system
Base Isolation
Base Isolation is a technique developed to prevent or minimise damage to buildings
during an earthquake. When a building is built away (isolated) from the ground,
resting on flexible bearings or pads known as base isolators, it will only move a little
or not at all during an earthquake.
The isolators work in a similar way to car suspension, which allows a car to travel
over rough ground without the occupants of the car getting thrown around. It is not
suitable for all types of structures and is designed for hard soil, not soft.
Lead rubber bearings were developed as base isolators in the 1970s. They consist of
three basic components – a lead plug, and rubber and steel, which are generally
placed in layers. Existing buildings can be retro-fitted with Base Isolation, an example
being Wellington’s Old Parliament Buildings.
Adaptive Reuse and Strengthening (page 53)
To help retain Christchurch’s unique charm, as well as making economic and environmental
sense, adaptive reuse and strengthening of character buildings is to be encouraged.
Adaptive Reuse
If a building is suitable for a new use after it is no longer needed or fit for its original use then
conservation through reuse must be considered. Christchurch’s character concrete buildings,
especially those that employ structural frame systems, are well suited to this type of
conversion and resource optimisation. In most cases, the concrete structure will not require
secondary fireproofing or acoustic treatment.
If an existing character concrete building cannot be used in its complete form at the end of its
life, then it can be deconstructed. Deconstruction is the partial or complete disassembly of an
existing building, and elements within it, to be reused in another building. It differs from
demolition in that the building components are still in their original component parts.
12 | P a g eAlong with heritage / social and economic reasons, adaptive reuse also offers many
environmental benefits, as the recovery of the energy and material resources embedded in a
building can be derived from the reuse of its elements or the complete structure.
While adaptive reuse of character (and heritage) buildings will inevitably form a key
component in conserving the positive aspects of Christchurch’s existing built identity, the
ability to reuse building elements or an entire structural frame must also be a driver in any
new construction. 21 Queen Street in Auckland is a recent example of adaptive reuse.
Through 'reuse and reduce’ 21 Queen Street meets all aspects of sustainable construction
Strengthening
The support and reinforcing of character (and heritage) buildings is another and equally valid
means to ensure that part of the city’s existing character is preserved. Concrete, whether
used in foundations or structural elements, is ideally suited to this task.
The combination of concrete and steel in reinforced concrete provides the three most
important properties for structural surety and in turn earthquake resistance: stiffness,
strength, and ductility.
A high-profile New Zealand example that clearly demonstrates concrete’s suitability for
strengthening heritage buildings in the wake of increased concerns over earthquake risk is
the Government Buildings Historic Reserve, more commonly referred to as the Old
Government Buildings, on Lambton Quay in Wellington.
This building, classified as "Category I" (places of special or outstanding historical or cultural
heritage significance or value) by the New Zealand Historic Places Trust, underwent
extensive restoration between 1994 and 1996, which included replacing all the original totara
wooden piles with concrete.
13 | P a g eOld Government Buildings, in Wellington was retrofitted with concrete foundations in the mid-1990s Retention and Reuse of Materials (page 54) The reuse of material, retrieved and retained from demolished heritage buildings is vital to enhancing the character of the redeveloped Central City, and to maintaining a visible link with pre-earthquake Christchurch. However, emphasis should be placed on a wider interpretation of retention and reuse, one that extends beyond heritage buildings to include the recycling of ‘waste’ material, in particular demolition concrete as aggregate. Within this understanding the encapsulation of demolition concrete in either new concrete or other applications such as roading sub-base, renders it crucial to Christchurch’s recovery from both environmental and economic perspectives. Canterbury based quarries and ready mixed concrete producers have the capacity to process demolition concrete into recycled aggregate. This involves grading the material, extracting the recyclable reinforcing steel, and producing various aggregate sizes. CCANZ acknowledges that the draft Central City Plan supports the NZGBC’s Green Star rating scheme for the performance of buildings, part of which rewards the incorporation of recycled materials in construction projects. However, Christchurch is faced with a significant amount of demolition concrete, the re-use of which, rather than occupying clean fill, must rate highly across a range of criteria important to the future urban design credentials of the Central City. Height and Human Scale (page 55) Creating an environment for the Central City that promotes a greater variety and more consistent density of activities, while at the same time maintaining a scale that respects remaining heritage buildings and contributes to people’s perception of safety is key to Christchurch’s regenerated city centre. Yet to impose a maximum low-rise 7-story limit on redevelopment is to restrict urban design possibilities from the outset, and in turn potentially prevent Christchurch from reaching its objective of becoming a Distinctive City. 14 | P a g e
Recent visiting speaker, Sir Richard Leese, leader of Manchester City Council, and the man
who spearheaded the reconstruction of Manchester's city centre after the 1996 IRA bombing
commented in relation to the draft Central City Plan that "Plans ought to open up
opportunities rather than close down opportunities.” (Sunday Star Times – 28 August 2011)
The implication of such a statement is twofold. Firstly, to place a limit on the number of
storeys in the city centre will inhibit the potential for Christchurch to achieve its stated aim of
good urban design. Secondly, height restrictions, along with a maximum gross floor area for
retail activities, will place commercial property in the Christchurch city centre at a
disadvantage compared to competing developments in other main centres.
It is imperative that Christchurch encourage private investment as a key vehicle for
revitalisation. If property development is obstructed by limits, however well intentioned, then
developers will not be able to meet demand, and the recovery of Christchurch, as well as the
wider Canterbury region, will be compromised from the beginning.
CITY LIFE
CCANZ supports the CITY LIFE initiative.
The vision for a rebuilt Christchurch city centre as offering varied living choices that fulfil the
community’s leisure needs as well as attracting visitors from across New Zealand and
overseas is a critical component of the overarching regeneration process.
A beneath ground gymnasium
The top protrudes above the
ground allowing in natural light
To implement this vision for a new kind of urban living, concrete-based construction
technologies and systems, as outlined below, must be integrated into what ever design
approach is adopted for the city’s future City Life.
Beneath Ground Structures
In dense urban environments such as city centres, the optimisation of available space
is incredibly important, as such ‘beneath ground’ structures provide a suitable means
in realise suitable public spaces and facilities for sport and the arts.
Beneath ground structures utilise concrete retaining walls systems to create
concealed spaces at levels below the ground of up to 3-storeys. These spaces can
be used for a multitude of purposes, such as gymnasiums, art galleries or libraries.
The top two-three metres can protrude above ground level to supply light if required,
otherwise fully concealed structures can receive natural light through roof windows.
15 | P a g eThe use of concrete in roof elements enables the requirements outdoor activities to
be met. For instance, sports fields and playgrounds can be accommodated, along
with or extensive planted and paved areas.
Affordable Housing (page 81)
CCANZ shares Christchurch City Council’s belief that the supply of quality affordable housing
for low-to-middle income earners is key to populating and sustaining a vibrant, energetic and
alive Central City.
When affordability is more broadly considered and engages with sustainability values such
as lifecycle costs, durability, health, energy efficiency and noise control, these concrete
construction in the residential housing sector offers a number of unique advantages.
Throughout New Zealand durability is of major concern, and concrete construction offers one
of the most durable options available. Concrete is not only impervious to wilful damage, it is
also fire resistant, provides excellent sound insulation, and security from intrusion. The
benefits afforded by concrete construction are particularly relevant if medium and high-
density housing is considered as an option to alleviate the shortage of affordable housing.
When durability is considered together with maintenance costs, concrete construction can
provide very effective lifecycle efficiencies far beyond the 50-years that the New Zealand
Building Code mandates as a building’s minimum lifespan.
In terms of living environment, the use of thermal mass and energy efficient design can
contribute to lower heating (and cooling) costs, a factor which is of significant concern to
those spending a substantial portion of their incomes on mortgages or rent. Recent research
advises that by 2030, space cooling will become a major concern for much of New Zealand’s
residential lightweight construction. The internal environments created using concrete are
also likely to be more healthy and quiet.
Sound Control
Central to an inner city environment conducive to residential inhabitants is the
capacity to safeguard people from distress as a result of undue noise being
transmitted between abutting occupancies. Many modern noise sources, such as
stereos and home theatre systems, have a low frequency content that can be
disturbing in adjacent tenancies.
CCANZ believes the noise provisions cited do not go far enough. Whilst a minimum
external sound insulation level is cited, there is no provision for internal sound
insulation between tenancies. This is particularly important in mixed use multi-
tenancy situations where ‘’bass beat’’ can be a significant cause of distress. Indeed
CCANZ recently commissioned social researcher CRESA to undertake research
which utilised social research techniques to explore:
• The incidence and prevalence of noise related problems experienced by
residents in multi units and apartments in higher density built environments.
• The building and building use factors that are associated with noise distress
among residents in multi-units and apartments in higher density built
environments.
16 | P a g eIn this national survey, CRESA concluded that over a third of participants (39.5
percent) reported that they would like their homes to be quieter, highlighting the
misery associated with low frequency noise in multi-tenancy situations.
Housing Showcase (page 82)
To demonstrate the concrete industry’s commitment to high quality, viable examples of
affordable housing, CCANZ is exploring opportunities with commercial partners to develop a
show home that exhibits all the benefits of residential concrete construction. The intention is
to display the outcome at the Housing Showcase inner-city neighbourhood proposed for
Christchurch as a means to communicate to prospective residents the inspirational results
that can be achieved through combining sustainable design principles with concrete.
At the same time, CCANZ is developing a concept design for excellence in concrete based
affordable housing under the brand name A+ Home. As both a single level and two-three
+
The CCANZ A Home, terraced
option, combines passive solar
design, durability and fire safety
for residential urban living
storey terraced concept, the A+ Home demonstrates that through design efficiencies, such as
harnessing the thermal mass of an exposed concrete floor slab or precast / concrete
masonry wall, an affordable, comfortable and strong home can be delivered to meet growing
demand in New Zealand.
TRANSPORT CHOICE
CCANZ supports the TRANSPORT CHOICE initiative.
The goal of improving travel choices to support the recovery of the Central City and help
renew economic prosperity lies at the heart of a new Christchurch. Balancing the wish for a
pedestrian-friendly Central City, along with the commercial realities of a busy market place
can be achieved in great part through the implementation of ‘shared spaces’. By allowing
both foot and vehicle traffic within the same zoned area, shared spaces essentially
guarantee ‘equal-rights’ amongst all those on the move. European experience has indicated
that shared spaces enhance awareness amongst all traffic participants, which in turn fosters
a more considerate attitude.
Shared spaces have one paving material across their entire width. Concrete paving flags
constitute the ideal material from which to construct shared spaces, as they are graded for
medium or heavy duty applications, while also being available in an extensive range of
17 | P a g eshapes, colours and textures. For light traffic applications within shared spaces pervious
concrete meets all requirements.
Shared spaces in the Netherlands… … and in Germany.
Shared spaces are increasingly popular across
European city centres
Whether shared spaces in conjunction with concrete paving flags are adopted as means to
facilitate the envisaged transport choices for a future Central City, the array of advantages
provided by concrete, as opposed to price sensitive bitumen based alternatives, must rank
highly amongst pavement and road options.
Concrete’s durability offers any investment in our roading significant potential returns. A
concrete road’s extended service life, low maintenance and reduced fuel consumption
benefits are all well documented and compelling economic factors for the adoption of
concrete roads.
The case for concrete pavements and roads has gained further credence in the wake of the
recent amendments to the New Zealand Transport Agency’s (NZTA) Economic Evaluation
Manual. Based on recommendations from the New Zealand Treasury, the NZTA has
18 | P a g eadjusted to 8% percent per annum (from 10%) the discount rate by which the cost and benefits of infrastructure projects are determined over time. The evaluation period for infrastructure has also been extended from 25-years to 30-years. A lower discount rate would most likely favour infrastructure projects that reduce the total cost of maintaining and operating the network, that is to say, those major infrastructure projects that require the long service-life afforded through concrete. Both these economic assessment factors for infrastructure projects now more accurately consider the range of advantages offered by concrete’s durability. Even so, they are still out of kilter with overseas practice. For instance, the current discount rates used by the UK Highways Agency are 3.5% up to 30-years, and then 3.0% from 31 to 60-years. From an environmental perspective the performance of concrete roads is also very encouraging. Along with research supporting concrete roads as requiring minimal maintenance and therefore causing less congestion and associated exhaust emissions, concrete roads also enhance the fuel efficiency of heavy vehicles by reducing rolling resistance. Furthermore, a recent whole-of-life study also identified concrete manufacture as requiring less primary energy, and therefore generating less greenhouse gases, than alternative roading materials. Another environmental factor, which elevates concrete roads for consideration, is that construction technology has advanced sufficiently over the past decade to address the issue of surface noise. An interesting property of concrete, with positive environmental implications, which is attracting increased attention, is its albedo – the ratio of the reflected solar energy to the total solar energy received. Put simply, the light coloured surface of a concrete road has a greater albedo than darker alternative roading materials. This translates to greater radiation reflectivity, which in turn slows the process of global warming. MARKET CITY CCANZ supports the MARKET CITY initiative. CCANZ notes a core theme of the Market City initiative is a compact CBD and indeed a Compact CBD Project is identified “..a compact central business district is vital for economic prosperity in the redeveloped Central City.” CCANZ concurs with this sentiment. Concerns remain however, that the proposed limit on the height of buildings in the CBD will be a significant barrier to economic development. Investors will doubtless require certainty that commercial buildings provide a viable return over the life of an asset and a blanket height restriction may lead developers to invest elsewhere. CCANZ seeks relief therefore that reference to height restrictions be removed and refer the reader to our earlier comments on pages 10-11. Furthermore the draft Central City Plan should be amended to delete references to removing existing use rights as again this could also undermine investor confidence. 19 | P a g e
DRAFT CENTRAL CITY PLAN VOLUME II-REGULATORY
FRAMEWORK
General Comment
Any regulation pertaining to height restrictions should be removed for the reasons identified
in earlier sections of this document.
Clause 6.2.1 Noise Residential activities
CCANZ believes the noise provisions cited do not go far enough. Whilst a minimum external
sound insulation level is cited, there is no provision for internal sound insulation between
tenancies. This is particularly important in mixed use multi-tenancy situations where ‘‘bass
beat’’ can be a significant cause of distress. Indeed CCANZ recently commissioned social
researcher CRESA to undertake research which utilised social research techniques to
explore:
• The incidence and prevalence of noise related problems experienced by residents in
multi units and apartments in higher density built environments.
• The building and building use factors that are associated with noise distress among
residents in multi-units and apartments in higher density built environments.
In this national survey, CRESA concluded that over a third of participants (39.5 percent)
reported that they would like their homes to be quieter, highlighting the misery associate with
low frequency noise in multi-tenancy situations.
The specification for internal sound insulation between tenancies should take advantage of
recent international research that shows that frequencies below 100Hz are important for
occupant satisfaction. In line with the proposed amendments to G6 clause of the Building
Code it is recommended to use the rating DntW for specifying sound insulation between
tenancies, but with the C correction with a lower frequency limit of 50 Hz. Thus the criteria
would be Dntw+C50 > 50 dB .
In addition, the same comment applies to clauses 8.6.1 (page 82), clause 2a.2.10 (page 100)
and 11.1.6 (page 203).
Clause 3.11.2 The Build Green Christchurch Tool (Pages 207-212)
The Build Green Christchurch Tool as outlined under this clause does not appear to be fully
developed. For example there are no points available for the heat island effect (for using light
coloured, high albedo materials). Furthermore, the mechanics around assessment criteria
have not been developed.
Changes to the Global Stormwater Consent requirements (Page
213)
A note should be inserted to ‘First Flush Treatment’ which highlights the importance of
pervious paving in mitigating the risks associated with stormwater pollution. Through cationic
exchange, pervious pavements trap the pollutants and heavy metals associated with
stormwater run-off.
20 | P a g eAppendix A - Concrete magazine - Pervious Concrete http://www.ccanz.org.nz/images/document/ConcreteMagazine/2011%2003.pdf 21 | P a g e
Appendix B - CCANZ Designing Comfortable Homes http://www.ccanz.org.nz/news-ccanz.aspx?id=65 22 | P a g e
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