February 2019 to February 2020
The Piha Footbridge is an lightweight economic steel truss footbridge designed for a residential developer in Piha, Westcoast Auckland. Clad in beautiful Accoya timber this is a truly elegant and cost effective addition to this native bush setting.
Resource consenting required that the new dwelling provided access over the existing river. The river required a 15m span bridge but access to the site was extremely limited meaning that 5m lengths were the largest deliverable. In response to the challenging site, a lightweight economic steel truss footbridge that could be bolted together onsite was devised. The economic steel truss footbridge provided the client with maximum flexibility: they could either a) deliver in three 5m lengths and bolt them together or b) bolt the entire truss together onsite. They opted for the later option.
The site is less that 200m from west-coast waves (good surf!) and the economic steel truss footbridge is painted gravel grey and is designed to resist the harsh west-coat marine environment. It is clad in accoya timber battens to create a modern aesthetic sympathetic to the modern house that is to be built.
The economic steel truss footbridge has been designed so that a welded “U-frame” is created that restrains the top flange from buckling. This prevents the need for outriggers or a top cross beam and is thus an elegant and cost-effective solution.
The bridge was delivered in association with our friends at Constructure Ltd. Constructure originally presented the idea of a lightweight truss footbridge to their client whilst designing the adjacent house (which is expected to be an architectural marvel once completed). Once the client was onboard with using a truss, Constructure contacted us to come on board and make it happen!
We are very pleased with the Piha Footbridge. It is a great showcase for how cost-effective lightweight footbridges can still produce architectural outcomes!
Dan Crocker
If you are interested in steel truss footbridges for your next project also check out the Wairoa Clip-on Cycleway Truss.
FOOTBRIDGE DELIVERY TEAM
Client = Private Residential
Project Manager = Constructure Ltd.
Architect = DC Structures Studio
Engineer = DC Structures Studio
BRIDGE SPECS
Date of construction = Feb 2020
Span = 15m
Width = 1.2m
Barrier height = 1.2m;
Live Load = Residential (2KPa) or maintenance “Dingo” (11kN)
Design Code = NZS1170 (Loading) & NZS3404 (steelwork)
Bridge Form = Lightweight steel truss footbridge
Paint System = Polyurethane 2-pack paint system (PUR5)
Paint colour = Resene “Gravel”
Timber decking & Balustrade= 32mm Accoya (Pine)
