An explosion that demolished a tractor-trailer full of a blazing plastic foam yesterday and left a key Highway 401 overpass closed for the day will continue to put the squeeze on drivers during this morning's rush hour.
The accident paralyzed traffic around the already-tight bottleneck where Canada's busiest highway meets the Don Valley Parkway, but Ontario Ministry of Transportation engineers and repair crews were at work all night to reopen two of the three 401 collector lanes on the affected overpass this morning.
Drivers in the 401 westbound express lanes today will still have no access to the DVP and Highway 404 off-ramp underneath the bridge, while workers repave asphalt melted by the fire and a repair crew chips away at loose concrete on the structure's blackened underside.
Early yesterday, a truck heading west in the 401 express lanes entered the off-ramp to the 404 and DVP, which dips underneath the overpass that carries the 401's westbound collector lanes, and smashed into the bridge's supports.
Yesterday, engineers with the Ministry of Transportation were called in to inspect the bridge because of fears it was no longer structurally sound, but had to wait a few hours before its well-done underside was cool enough. The soot-covered concrete girders were still radiating 100-degree heat, a spokesman said, even 12 full hours after the fire had started. Engineers, including some brought in from ministry headquarters in St. Catharines and armed with flashlights and hammers, knocked chips of damaged concrete off the structure, examining the surface for telltale cracks and flaking that might reveal whether the web of steel rebar inside each of the bridge's metre-wide girders had been fatally weakened by the hot fire.
"Have you ever been near burning Styrofoam? That stuff is hot. It's a product made from chemicals, from petrochemicals, so when it burns, it burns hot," Mr. MacKenzie told reporters.
Ministry officials initially did not rule out that a long closing or a total rebuilding of the bridge might be necessary, Mr. MacKenzie said, adding that years ago, a brand new highway overpass once had to be rebuilt after a propane tanker exploded in Milton.
The bridge dates from the late 1960s, ministry spokesman Will MacKenzie said, and the steel inside its precast concrete girders is designed to handle temperatures ranging from -40 to 40 C, so a big fire with temperatures much higher would be sure to do some damage.
But by midafternoon yesterday, Mr. MacKenzie announced that with some "quick-fix" repairs, it would likely be possible to open the two northernmost lanes of the overpass by early this morning. Crews were to redraw the road markings to shift traffic to the north half of the bridge and keep the weight of passing cars and trucks from pounding on the most damaged portion.
Drivers in the westbound 401 express lanes will still have no access to the DVP or 404 today and possibly for longer, Mr. MacKenzie said, as crews need to repave the road and continue with more extensive bridge repairs.
"There's some loose surface concrete that they want to have removed before they can open the lanes underneath," Mr. MacKenzie said. "They just don't want bits and pieces dropping onto vehicles below."
He said the off-ramp will be temporarily narrowed to one lane when it does reopen, to allow crews to continue repairs on the bridge that could take weeks.
Police believe the driver - helped by an OPP officer and a passing motorist and taken to the Sunnybrook Health Sciences Centre with serious burns - may have taken the turn too fast, lost control of the truck and slammed into the concrete pillars that support the overpass.
His vehicle then exploded and the highly flammable load burst into a spectacular fire that produced what police described as rivers of flaming diesel. The inferno left almost no trace of the truck.
Jeff Gray