Parramatta Square (PS) is a major three-hectare precinct in the heart of Parramatta—Sydney’s second CBD—featuring a vibrant mix of residential, commercial, and retail spaces.

BG&E provided civil, flooding and drainage services for Parramatta Square, a project of significant scale and importance to the community. Located in the heart of the city, this development has firmly established Parramatta as a modern destination and one of Greater Sydney’s three CBDs.

Parramatta Square is a three-hectare mixed-use precinct developed by Walker Corporation, consisting of a total of six stages and accommodating a mix of commercial, education, and retail developments.

3PS, 4PS, and 6PS/8PS are Class A commercial office towers with a 5 Star rating, directly adjacent to the Parramatta Train Station and the main western train line.

BG&E provided schematic design development in close collaboration with the architect, along with civil, flood, and drainage design services through to construction.

Civil design included

• The upgrade of two intersections.
• Reconstruction of 350 metres of Darcy Street which provided the frontage to 4PS and 6PS/8PS.
• The public domain, a large paved area (4,800 square metres) including an outdoor dining facility, seating area, and a major pedestrian thoroughfare to Parramatta Train Station.

BG&E’s role included road design, pavement grading, stormwater drainage, subsoil drainage design, utility coordination, water-sensitive urban design, and erosion and sediment control.

Flooding & drainage

BG&E was commissioned to undertake a flood assessment of the site to consider local overland and mainstream flooding from the Parramatta River, including

• Developing a 2D hydraulic model for the Parramatta CBD to understand the local overland flood and to provide the best flood protection measures.
• Developing the baseline model scenario to set critical flood levels and flood patterns for the existing scenario.
• Preparing flood maps and reports and working with the architects to determine the design levels throughout the site based on the design criteria.
• Developing scenarios to determine the new building floor levels, basement carpark entries, and redeveloped pedestrian walkway entry to the Parramatta Train Station. The results have been used to inform automatic and manual flood barrier and flood door designs to provide the most effective flood mitigation strategies.
• Diverting large trunk stormwater drainage infrastructure through the site to accommodate the development of the site.

3 Parramatta Square

3 Parramatta Square (PS) is a 16 level mixed-use commercial tower, which serves as the National Australia Bank’s new headquarters, as part of the mega three-hectare PS precinct development. The 3 PS commercial tower is comprised of premium A-Grade office space, childcare facilities, a central atrium, three basement parking levels, a mezzanine level and ground floor podium with 412 square metres of retail space.

BG&E provided structural and civil engineering design services for the commercial tower, which boasts custom-designed tenancy fit-outs and striking architectural features, such as one of the largest naturally lit atriums of any commercial building in the country and full-height glass facades. The structural concept design was provided to Walker in 2016, which was novated to Built for construction.

The temporary retention strategy around existing shoring and anchoring constraints along the site boundary presented a challenge, in addition to keeping the existing basement dive ramp operational throughout construction. BG&E’s design avoided the use of conventional ground anchors, while careful coordination with Built saw the internal strut layout design avoid potential clashes between temporary and permanent structures. The collaborative design process enabled smooth and successful construction.

Construction of 3 PS was completed in 2020, providing a structure for vital banking, childcare and retail facilities to support a thriving new precinct.