Bassett M.,Building Research Association Of New Zealand |
Overton G.,Building Research Association Of New Zealand
Buildings | Year: 2015
Residential buildings are now better engineered to manage rainwater following the leaking building problem in New Zealand. The next challenge is to improve the weathertightness of medium-rise buildings which often use joint details widely applied on low-rise buildings but are subject to higher wind pressures and surface runoffrates. This study begins to address this challenge by measuring the water leakage performance limits of the following common flashings with static and dynamic rain and wind loads to see how their performance might be improved: (a) Horizontal H and Z jointers between direct fixed sheet claddings; (b) The window head flashing in a cavity wall; (c) A horizontal apron flashing at the junction between a roof and wall. At this stage, water penetration resistances have been measured but the data has not yet been discussed in the context of wind pressures and rain loads on mid-rise buildings. All of the joints were found to resist water leakage to pressures equivalent to the hydrostatic head of the upstand, so long as there were no air leakage paths through the joint. When vents were added, or openings were present that might arise due to construction tolerances, then the onset pressure for leakage was found to fall by as much as 50%. Vents, of course, are essential for ventilation drying in rainscreen walls and even with vents present, the onset of leakage was at generally at least twice the 50 Pa wet wall test pressure applied in New Zealand. Opportunities were found to improve the way vented joints deal with runoffby enlarging the gap between the cladding and flashing. This prevented the outer joint volume from filling with water and occluding the vents. The apron flashing was found to cope better than a window head joint with runoff, because of the larger 35 mm vertical gap between the cladding and apron. © 2015 by the authors.
Cory S.,Victoria University of Wellington |
Donn M.,Victoria University of Wellington |
Pollard A.,Building Research Association Of New Zealand
Buildings | Year: 2015
The New Zealand building design industry assumes various building model inputs for the consumption of energy through lighting and appliances. It also makes assumptions regarding when these energy consumers are considered to be "turned on". This paper aims to better inform industry energy modellers about the real load and operation of real commercial buildings in New Zealand when compared to New Zealand Standard energy efficiency requirements and assumptions. The paper presents a set of New Zealand relevant commercial building operation information. Typical operation information is provided for three commercial building types: (1) Office; (2) Retail; and (3) Mixed/Other. The information provides low, typical, and high installed building load and operation pattern scenarios for the three building types. The typical data presented in this paper is significantly different to the load requirement and operation modelling assumptions presented in the New Zealand Building code. The results established in this paper are informed by data gathered in the Building Research Association of New Zealand (BRANZ) Building Energy End-Use Study (BEES). The purpose of BEES is to increase knowledge on energy use patterns for the entire New Zealand building stock. The intention of this paper is to disseminate the established knowledge that will eventually update the assumptions used in New Zealand commercial energy models. © 2015 by the authors.
Wickstrom U.,SP Technical Research Institute of Sweden |
Robbins A.,Building Research Association Of New Zealand |
Baker G.,Building Research Association Of New Zealand
Journal of Structural Fire Engineering | Year: 2011
Ongoing international collaborative research clearly demonstrates that the concept of adiabatic surface temperature is a simple single parameter to describe the complex convective and radiative conditions to which the surface of a structural element is exposed during fire. This parameter is a convenient and simple interface between fire and thermal/structural models. This paper presents existing published and new unpublished research for fire/structural engineers so as to contribute to the advancement of the engineering practice of designing structures in fire.
Collier P.C.R.,Building Research Association Of New Zealand
Fire and Materials 2013 - 13th International Conference and Exhibition, Conference Proceedings | Year: 2013
Passive fire protection (PFP) systems that are damaged by earthquakes may suffer significant reductions in fire resistance, resulting in increased risks to life safety in the event of an outbreak of post-earthquake fire and subsequent spread. In the aftermath of the Canterbury (New Zealand) earthquake events, damage to PFP systems has been surveyed in moderately damaged buildings. The degree of damage observed ranged from minimal, to moderate damage where some fire resistance remains, to extensively damaged where no protection remains. This paper focuses on damage in the moderate range where the majority of PFP systems protecting a fire compartment were largely intact, but one or two systems such as a doorset or a firewall were showing some degree of damage that compromises the protection of the whole fire compartment. Following the building surveys, selected elements of damage to PFP systems were built into the fire resistance test specimens as defects and instrumented with thermocouples to assess the failure mechanisms. The reduction in fire resistance of the damaged systems was correlated to the degree of damage such as size of gaps, furnace pressure and oxygen content of the fire gases and then compared with fluid flow theory in restrictive openings. Traditionally, the focus has been on the risk of fires immediately following an earthquake event when the occupants are evacuating, and damaged PFP coupled with inoperable sprinklers due to loss of water supply and impeded egress routes are likely to impact life safety. It is now also acknowledged that PFP may be damaged in an otherwise structurally safe building that may be reoccupied postearthquake; this research also provides a basis for building assessors to require that damaged PFP be restored to specification.
Yeoh D.,University Tun Hussein Onn Malaysia |
Fragiacomo M.,University of Sassari |
Carradine D.,Building Research Association Of New Zealand
Engineering Structures | Year: 2013
In recent years, timber-concrete composite systems have become more widely used as a new construction technique for buildings and bridges. The main advantage is that the compressive strength of concrete is exploited through the use of composite action while timber beams are able to resist the tensile stresses. The level of composite action, which can be achieved by the system, is dependent on the type of shear connector used. There is a lack of knowledge, however, on the performance of these types of connections when subjected to cyclic loading, which is typical for bridges. Testing was performed in the Structures Laboratory of the University of Canterbury to analyse the fatigue behaviour of two types of timber-concrete connections via push-out specimens, and two beam specimens representing strips of composite floor with the same connection types. The two types of connection investigated were: (i) a rectangular notch connection reinforced with a coach screw (also known as lag screw); and (ii) a connection with toothed metal plates punched into laminated veneer lumber (LVL). The stiffness of the connection was monitored throughout the cyclic loading along with the total amount of slip occurring between the concrete and timber. After the application of 2. million cycles, the push-out and beam specimens were loaded to failure in order to quantify their maximum strength. The strength of the rectangular notched connection after cyclic loading was 0.95 times of the one without cyclic loading, while for the metal plate connection was 0.60 times. For the metal plate connection, a continuous increase in slip was observed with increased cycles possibly due to accumulated damage from repeated loading. The rectangular notch connection displayed more resistance to changes in slip, strength and stiffness than the metal plate connection. No obvious loss of stiffness was observed in the rectangular notch connected floor beams after 2. million cycles, and when tested to failure the stiffness was very similar to the same floor beam that had not been cyclically loaded. The floor beam with metal plate connections did not perform well and failed after 350,000. cycles. The loss of strength, stiffness and composite action in this floor beam compared to the one without cyclic loading was significant. In this respect, the rectangular notch connection system is recommended for use in bridge design as opposed to metal plate connections. © 2013 Elsevier Ltd.
Keall M.D.,University of Otago |
Pierse N.,University of Otago |
Howden-Chapman P.,University of Otago |
Cunningham C.,Massey University |
And 3 more authors.
The Lancet | Year: 2015
Background Despite the considerable injury burden attributable to falls at home among the general population, few effective safety interventions have been identified. We tested the safety benefits of home modifications, including handrails for outside steps and internal stairs, grab rails for bathrooms, outside lighting, edging for outside steps, and slip-resistant surfacing for outside areas such as decks and porches. Methods We did a single-blind, cluster-randomised controlled trial of households from the Taranaki region of New Zealand. To be eligible, participants had to live in an owner-occupied dwelling constructed before 1980 and at least one member of every household had to be in receipt of state benefits or subsidies. We randomly assigned households by electronic coin toss to either immediate home modifications (treatment group) or a 3-year wait before modifications (control group). Household members in the treatment group could not be masked to their assigned status because modifications were made to their homes. The primary outcome was the rate of falls at home per person per year that needed medical treatment, which we derived from administrative data for insurance claims. Coders who were unaware of the random allocation analysed text descriptions of injuries and coded injuries as all falls and injuries most likely to be affected by the home modifications tested. To account for clustering at the household level, we analysed all injuries from falls at home per person-year with a negative binomial generalised linear model with generalised estimating equations. Analysis was by intention to treat. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12609000779279. Findings Of 842 households recruited, 436 (n=950 individual occupants) were randomly assigned to the treatment group and 406 (n=898 occupants) were allocated to the control group. After a median observation period of 1148 days (IQR 1085-1263), the crude rate of fall injuries per person per year was 0·061 in the treatment group and 0·072 in the control group (relative rate 0·86, 95% CI 0·66-1·12). The crude rate of injuries specific to the intervention per person per year was 0·018 in the treatment group and 0·028 in the control group (0·66, 0·43-1·00). A 26% reduction in the rate of injuries caused by falls at home per year exposed to the intervention was estimated in people allocated to the treatment group compared with those assigned to the control group, after adjustment for age, previous falls, sex, and ethnic origin (relative rate 0·74, 95% CI 0·58-0·94). Injuries specific to the home-modification intervention were cut by 39% per year exposed (0·61, 0·41-0·91). Interpretation Our findings suggest that low-cost home modifications and repairs can be a means to reduce injury in the general population. Further research is needed to identify the effectiveness of particular modifications from the package tested. © 2015 Elsevier Ltd.
Collier P.C.R.,Building Research Association Of New Zealand |
Baker G.B.,Building Research Association Of New Zealand
Fire Technology | Year: 2013
Concerns exist both in New Zealand and internationally about the performance in fire of insulated panel, particularly relating to the combustibility of polymer foam core materials. The focus of this paper is the most commonly used panel product in New Zealand, polystyrene insulated panel (PIP), with its core of expanded polystyrene. A series of experimental research projects were conducted to investigate the fire performance of the material. The objective of the research programme was to quantify the fire performance, using oxygen depletion calorimetry, of different construction details. In addition, laboratory experiments also investigated the influence of fire retardant treatment and the issue of fire spread in panel cavities. The major conclusion of the research was that maintaining the integrity of the metal skins of PIP had a quantifiable and significant beneficial impact on the fire performance of PIP. © 2011 Springer Science+Business Media, LLC.
Robbins A.P.,Building Research Association Of New Zealand |
Wade C.A.,Building Research Association Of New Zealand
Fire Safety Journal | Year: 2010
The current New Zealand prescriptive code for fire safety allows unlimited firecell floor area if at least 15% of the roof area is designed for "effective fire venting". However neither a definition nor performance criteria for "effective fire venting" is provided. Transparent and semi-transparent 'plastic'-type panels that have been installed for natural lighting requirements have been assumed to provide passive fire venting, based on misperceptions of generic 'plastic' performance in the event of a fire. The fire venting performance of these roof panels has not been proven. Therefore guidance on the use of roof panels for passive fire venting is required. © 2010 Elsevier Ltd. All rights reserved.
Uma S.R.,Institute of Geological & Nuclear Sciences |
Beattie G.,Building Research Association Of New Zealand
Bulletin of the New Zealand Society for Earthquake Engineering | Year: 2011
In Christchurch, the industrial sectors with storage facilities incurred heavy economic loss due to the collapse of pallet rack systems and loss of contents during the recent the Darfield (2010) and Lyttleton (2011) earthquakes. The failure of such systems could be attributed to various reasons including inadequate design, inappropriate operational conditions, improper installation and lack of maintenance. This paper describes possible sources of damage in pallet racks due to earthquake action, which eventually could trigger the collapse failure mode of the storage system during a severe aftershock. Various racking manufacturers and retail owners were consulted to establish the pre-event condition and loading of the systems and the response of the systems in both 'publicly accessible' and 'industrial' situations. Investigations by the authors highlighted an apparent lack of consistent national control over the design and construction of racking systems. Progress towards the publication of a revised and extended Design Guide is also described.
Buchanan A.,University of Canterbury |
Carradine D.,University of Canterbury |
Beattie G.,Building Research Association Of New Zealand |
Morris H.,University of Auckland
Bulletin of the New Zealand Society for Earthquake Engineering | Year: 2011
The earthquake on 22 February 2011 was very close to Christchurch city, generating very high level ground excitations that caused severe geotechnical effects and widespread structural damage. This paper outlines the wide range of damage to houses resulting from liquefaction, lateral spreading, rockfall, and horizontal and vertical ground accelerations. The response of typical forms of house construction and structural components are discussed, with many different types of damage described. The majority of houses in the Christchurch region are one or two storey light timber frame buildings. This type of construction has performed extremely well for life safety, but thousands of houses have some degree of structural or non-structural damage. The New Zealand Building Code needs to be reviewed in several areas, especially the requirements for foundations and reinforced concrete floors.