In Saigon, many engineers and other workers stay singularly focused through the night to ensure Southeast Asia’s longest river tunnel is traffic ready.
In Saigon, many engineers and other workers stay singularly focused through the night to ensure Southeast Asia’s longest river tunnel is traffic ready.
The Saigon River Tunnel, known formerly as Thu Thiem Tunnel, opened to traffic in November 2011, connecting downtown District 1 with District 2, a favored residential area by many expats.
The tunnel lies 27 meters under the Saigon River at its deepest point as it runs 1.49 kilometers (less than a mile) from one end to another. It is 33 meters wide and nine meters high with six lanes, apart from two emergency exit lanes.
In order for the tunnel to serve traffic from 3 a.m. until 11 p.m. every day, a team of nearly 70 Vietnamese engineers and workers engage in maintenance work every night after it shuts down to traffic.
A group of around 20 workers clean the road surface and the panels that help reflect light inside the tunnel.
"What people normally see is dense traffic every day through this tunnel. What they don’t see are us workers who are here every night, working until almost 4 a.m. when the tunnel reopens to traffic. Without regular cleaning, the tunnel would be really dirty because of all the dust, soil and sand falling from trucks," said Nguyen Thai Uy, who was spraying water on the panels.
Around half an hour after midnight, engineers Nguyen Tuyen Hung and Dang Ngoc Hoa start their work of cleaning and maintaining the jet turbines on the ceiling of the tunnel. There are 12 such turbines inside the tunnel that circulate the air. They are checked every six months and normally, the cleanup and maintenance lasts two nights in a row.
Engineer Hoa wears protective clothing and a gas mask as he cleans a turbine. "I’ve been doing this job for two months now. It has become normal to me. What bothers me most is all the dust and the fact I have to stay at a high point, so I need to be equipped with all the safety tools."
Engineers Nguyen Tuyen Hung and Doan Van Tai check one of the two emergency exit lanes running along the tunnel. There are 40 doors to these lanes inside the tunnel.
Three engineers check and clean the electrostatic air filter, which is considered "the lung of the tunnel." This system is cleaned once a month.
"I find this job fun and suitable for me. It’s too dusty, though. Every time we finish the job, we look just like miners," said Nguyen Thanh Tan, who has done the job of cleaning electrostatic air filters for almost a decade.
Engineer Nguyen Hoang Long adjusts a device to collect data for monitoring the condition of the tunnel, sitting a specialized vehicle for the job.
"Every three months, other people and I will use a laser scanner and a thermal sensor camera system to see if there are any cracks or moistened areas inside the tunnel."
This job requires complete accuracy and should cover every millimeter of the tunnel, he said, adding that it should not be done on rainy days.
An SUV equipped with laser scanning device moves slowly along the tunnel. Sitting inside, Long devotes all his attention to the data collected.
"The vehicle must move steadily at the speed of less than 20 kilometers per hour for scanning. To collect the most exact data, it will scan each lane three times and normally, the job will last the whole night.
"After every scanning run, we normally collect up to 60GB of data. We will analyze it and compare it with the original one when the tunnel was first put into use to evaluate the actual condition."
A group of workers takes a break near the gate to the tunnel at 2 in the morning.
"The job is hardest in rainy days because of all the mud," said a cleaner named Nguyen Thi Bich Hanh.
Rain or shine, all workers and engineers have to finish their work before 4 a.m. so that the tunnel can reopen to traffic for another day.
Around 100 meters from the tunnel is the operation room where the remaining staff of the Management Center of Saigon River Tunnel take turns to keep watch around the clock.
Official data shows around 52,000 automobiles and 300,000 motorbikes use the tunnel every day. The tunnel is designed to stay for 100 years and withstand a 7-magnitude earthquake.
