Carreg a Gwydr is an iconic glass and stone residential structure that won the 2012 RIBA Welsh Architecture Award and was awarded The Daily Telegraph and Homebuilding & Renovating Award 2012 for Best Contemporary Home and Overall Winner.
Designed by Riba, Hall and Bednarczyk, Carreg a Gwydr takes a complex structural form, incorporating a large glazed facade, framed by exposed CHS columns, which wraps around the flanks of the structure and supports a cantilevered first floor balcony. The design incorporates curved reinforced block-work walls to the rear elevations which work in combination with a rigid steel sway frame to allow a bracing free arrangement. Columns are expressed in the open plan living space through a fully glazed elevation, punctuated with full width balconies and slender cantilevered roof overhangs.
Azimuth Structural Engineering Ltd, a leading specialist in the design of bespoke residential properties with contemporary architecture, was appointed as the consulting structural engineer on the challenging project. Azimuth’s structural designs had generally used a combination of analysis tools, calculation software and hand calculations, but this design required Azimuth to embrace new ways of working.
Critical stability assessment
Azimuth invested in Fastrak, the steel design software solution, to undertake the 3D structural analysis and design of Carreg a Gwydr.
The brief precluded any vertical cross bracing for stability and, due to the extent of glazing, accurate assessment of deflection from all wind directions was critical. Using Fastrak was pivotal to predicting and controlling these deflections, determining connection forces in the sway frames, and providing verification that the proposed structural form was viable. Fastrak enabled Azimuth to create one single model of the structure, incorporating faceted shear walls to represent the block-work walls and a steel sway frame with cantilevers at both the first floor and eaves level. Azimuth used Fastrak’s inbuilt wind calculator to determine wind deflections accurately and the 3D model was able to provide an optimized and automated design of the steelwork members.
Trying out various solutions
By using Fastrak, Azimuth could deliver a wide range of engineering services on the Carreg a Gwydr project, including the steel superstructure, the design of the basement sub-structure and a floating glass and timber staircase.
“Carreg a Gwydr would have been a more complex and time consuming project without Fastrak; it has definitely changed the way we work. Design can take a more freeform approach in the early stages of development, enabling us to communicate structural ideas with the architect quickly. Fastrak allows us to try various structural arrangements in a short timeframe to determine the most efficient structural form for a particular project,” says Laurence Boakes, Director of Azimuth.
Having made the investment, Azimuth now uses Fastrak regularly to help achieve realistic and efficient designs in similarly challenging projects with complex geometry.
“We have grown to enjoy an enviable reputation with regards to providing structural solutions for challenging situations. Fastrak supports us in delivering innovative but cost effective designs that enable our clients’ requirements to be fully realized,” Boakes concludes.