The female engineer shaping Singapore’s infrastructure

Text: Vivien Yap

While working on the construction of Singapore’s sixth MRT line, the Thomson–East Coast Line, Er Jee Yi Yng – better known as YY amongst professionals in the industry – encountered a critical challenge during the early stages of construction. A planned tunnel was found to be encroaching on the existing pile foundation supporting a tall building. 

Pile foundations are structures consisting of long vertical columns made of different materials, driven deep into the ground to support heavy structures.

“It was a critical problem as time is critical for the engineering team to provide a feasible solution,” she recalls.

Extensive studies, analyses and rigorous work were undertaken to ensure both the tunnel and the building could be built safely. The episode cemented her reputation as a technically skilled leader who stays composed under the pressure of new challenges.

Er Jee Yi Yng in a tunnel during the construction of an Mass Rapid Transport (MRT) line in Singapore. (Photo: AECOM)

Today, as Managing Director of AECOM Singapore and Senior Vice President for Southeast Asia, she leads more than 600 engineering professionals across the region.

A registered Professional Engineer (PE) and Specialist PE in Geotechnical and Tunnelling, she has contributed to some of Singapore’s most important transport infrastructure, including the Thomson-East Coast Line, Tuas Terminal Phase 2 and the Johor Bahru–Singapore Rapid Transit System Link.

She is also a trusted voice amongst the engineering industry as a Board Member of the Professional Engineers Board and Committee Member of the Tunnelling and Underground Construction Society Singapore.

In 2025, she received the Civil and Environmental Engineering Outstanding Alumni Award from NTU, recognising not only her technical mastery but also her leadership and service to the profession.

The Class of 2000 graduate of NTU’s School of Civil and Environmental Engineering has been interested in building things from a young age. She would stack spare bricks in the backyard of her childhood home in Malaysia to make shelters for small animals.

That curiosity stayed with her when she moved to Singapore at 17 and enrolled in Singapore Polytechnic, before receiving a scholarship from L&M Foundation Specialist Pte Ltd to pursue her studies at NTU.

Yi Yng’s time at university deepened her knowledge about civil engineering through meaningful practical lessons. She still remembers the In-House Practical Training, where she and her batchmates mixed concrete, cast it and tested its strength days later.

Beyond the classroom, a field trip to the now-defunct Choa Chu Kang Wastewater Treatment Plant also inspired her greatly. “Watching first-hand how wastewater was filtered and then repurposed showed me how civil engineering truly helps society,” she recalls.

During an internship with her sponsoring company, she received crucial advice from her supervisor: “He told me that if I wanted to learn something real, I should not work like an intern but as if this was my full-time job.”

She took that advice seriously, making multiple trips to check soil strength metre by metre on site and validating designs.

Yi Yng’s first job involved pile foundations – designing and overseeing construction of the supporting vertical columns that would support heavy building structures.

Within a few years, she earned the trust of senior leaders and rose quickly through the ranks.

The building blocks of a nation

Yi Yng continues to push boundaries. Her team now works on solutions for the Pulau Semakau Landfill, which is reaching capacity. Rather than simply sourcing sand to create new land, they are exploring ways to recover materials from the landfill itself.

Despite her years of experience as an engineer, finding a solution to extend the land area of Singapore’s only landfill poses a rewarding challenge for her.

Her seniority does not prevent her from asking her colleagues for help and advice when developing solutions.

“Civil engineering has changed. Today, we are looking at new issues like rejuvenating old train systems and creating sustainable land solutions. As civil engineers, we need to make sure that what we build integrate seamlessly into society while improving the lives of people,” she explains.

Yi Yng (left) receiving the Outstanding Alumni Achievement Award from Prof Boh Wai Fong, NTU Vice President (Lifelong Learning & Alumni Engagement, pictured on the right) at the School of Civil and Environmental Engineering (CEE) Alumni Awards 2025. (Photo: NTU)

Yi Yng hopes to shine a spotlight on the vital role engineers like her play in building cities and improving lives. As Singapore grows more complex and climate-conscious, her voice – along with those of her peers – carries increasing influence.

She advises early-career engineers to be patient, curious and bold: “Do not approach work mindlessly, but with heart. Most importantly, don’t be afraid to speak up.”