Northern Virginia motorists will face several new commuting problems this month as road crews begin redecking a bridge and ramps to several Shirley Highway interchanges.

In the Springfield area, several bridge ramps will be redecked at the interchange of Interstate Rtes. 95, 395 and 495. They are: the I-395 ramp extending west on I-495; the I-95 west ramp to north I-395; the I-495 east ramp to north I-395 and the I-95 west ramp onto southbound I-95. The cost of these projects totals $432,214.

Traffic will be reduced from two lanes to one lane on the ramps while work is under way, except for the I-95 west ramp onto southbound I-95. On this ramp, lanes will stay open during rush hours, while periodic lane closures during off-peak hours can be expected.

According to the Virginia Department of Highways and Transportation, the bridge roadways on north and southbound I-95 will be replaced over Furnace Road, near Occoquan. All lanes of traffic will be maintained while work is under way, with traffic routed onto the road shoulders. The $661,000 project will be completed in the spring of 1985.

Highway officials say some ramps could be finished by mid-November. If not, work will stop and be resumed in the spring. David Gehr, the Northern Virginia highway administrator who presides of 4,000 miles of Virginia's busiest roads and some of the area's worst traffic jams, said it is important to clear the bridges of construction equipment before it snows.

Eddie Reid, a department spokesman, said no specific starting date has been set. He could not estimate what kind of delays might be expected, except that traffic could be heavier than usual, particularly during rush hours. "Hopefully, they won't be sitting in traffic for too long unless too many of them get to the same place at the same time," he said.

When asked for advice, he said the only thing motorists can do is be patient. "Or, take an alternative route -- if you think it's bothering you enough. And, just hope everybody else doesn't think the same way you do."

Reid said the bridge and bridge ramps are among the many highway structures that are under repair or slated for repair in Virginia and the rest of the country.

"We started building most of these roads in the '50s and '60s, so it's about time to do something in terms of rebuilding them, repairing them or widening them," he said.

Northern Virginia highways are especially difficult to maintain, Reid said. "You get so many cars over them that they get old quick. That's what wears them out, besides just time. And, snow removal. Every winter you get a little more damage done to them."

Repairs will consist mostly of chipping worn concrete out of the road surfaces and replacing it with about one inch of new concrete, Reid said.

According to Lynda South, spokesman for the Virginia Department of Highways and Transportation, the contractor for the Springfield interchange project will be Marbro Co. Inc. Work is expected to begin Sept. 10.

The contractor for the I-95 bridge is J & C Construction, according to South. Work is expected to begin in two weeks.