MARTINEZ -- Keep it up.

That's the message voters appeared to send the Contra Costa Community College District this week, narrowly approving a $450 million bond measure to continue improving aging schools.

With some vote-by-mail ballots still being counted, Measure E had received 56.7 percent of the vote as of Wednesday afternoon. It requires 55 percent approval. College district officials were confident the result would stand when all votes are in.

Measure E's approval doubles the annual amount Contra Costa property owners now pay the district each year from $13 per $100,000 in assessed value to $26. It comes on the heels of similar bonds passed in 2002 and 2006.

"It's such a vote of confidence and enables us to continue the work we've already started," Chancellor Helen Benjamin said Wednesday. "It shows we have a good reputation and that we're doing what we say we're going to do."

Board president John Marquez said people raised concerns throughout the campaign about higher taxes, but what resonated with voters is that many campus buildings date back to the 1950s.

"When looking at the total picture, I think they saw that it would benefit all of us; not just the students but the entire community," he said.

A key factor for voters is that the new buildings would provide accessibility for the disabled, particularly veterans, Marquez said.

Design work will now start on a new $34 million campus in Brentwood, said Ray Pyle, the district's chief facilities planner. The 17-acre campus will be located on district-owned land off Marsh Creek Road south of the city.

"It's on open land, so we can start without having to worry about any constraints," said Pyle, noting that the district has been mindful not to make construction too disruptive.

The new campus also stands to receive money as part a November statewide school construction bond.

Meanwhile, leadership teams at each of the three campuses -- Los Medanos College, Diablo Valley College and Contra Costa College -- will help set design priorities, Pyle said.

Projects on the table include seismic retrofitting of existing CCC buildings and a new Science and Allied Health building; renovating DVC's Engineering Technology, Music and Performing Arts buildings; and new Student Activities and Performing Art buildings at LMC.

Trustees will also have to consider how to divvy up the money. The 2002 and 2006 bonds were split evenly by campus, though some adjustments were made on the latter because of seismic retrofitting issues, Pyle said.

The new bond would likely have to account for the size and age of the campuses, he said.

A goal is to start designing the new projects so work can start once those on the 2006 bond list are complete. "We want to jump right in so that there's no downtime," Pyle said.

Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.