The Architect of the Capitol has awarded the contract for construction of the second phase of the Capitol Visitor Center to an Oklahoma company for $144 million, about 20 percent higher than CVC officials had hoped to allocate for the project’s electrical, mechanical, plumbing and finishing work.

Manhattan Construction Co., headquartered in Tulsa with offices in Washington, D.C., was awarded the contract on Friday for “sequence two.” That final phase includes the buildout of the interior spaces, installation of the electrical, mechanical and plumbing systems, coordination with existing Capitol building systems, completion of the East Front Plaza and related site work and security elements.

The second phase will overlap for about a year with the first, which comprises construction of foundation walls, excavation, installation of load-bearing elements, portions of site utility work, completion of the roof slab and construction of a service tunnel under Constitution Avenue.

CVC officials have said that the first phase will be completed a year from now.

A $100 million contract for the first phase was awarded last June to Centex Construction of Fairfax, Va., and sources say the company also competed for the second contract.

Initially estimated at $265 million, the CVC’s budget has grown to $373.5 million, with the addition of a $38.5 million appropriation for security enhancements and an additional $70 million for the completion of “shell” space allocated for the House and Senate on each side of the visitor center. Both supplemental appropriations corresponded to a change in scope, rather than additional funds for original plans.

Upon hearing word last month that bids for the second phase had come in high, some lawmakers expressed concern that the project would require an additional appropriation without a corresponding change in scope. But CVC spokesman Tom Fontana had said last month that any higher-than-expected contract would have to be approved by the Capitol Preservation Committee, made up of leaders from both sides of the Capitol. It is not clear whether that has occurred, but the award of the contract signals a commitment on the part of House and Senate leaders to fund it.

And despite some grumbling from Rep. Jack Kingston (R-Ga.), chairman of the House Appropriations subcommittee on the legislative branch, and House Appropriations ranking member David Obey (D-Wis.), the project enjoys broad support.

At a Senate oversight hearing last month, Architect of the Capitol Alan Hantman defended the additional costs, noting the figures are “considered to be within an acceptable and reasonable range” of the estimates according to General Services Administration and Defense Department standards. He attributed the increase to “market conditions,” noting numerous construction projects elsewhere in D.C.

Hantman also said some of the unobligated funds were needed for unforeseen obstacles, including inaccurately documented utility lines, which required contractors to reroute a 30-inch water main.

The second phase contract also brings officials closer to knowing a possible completion date for the project. Fontana has said that contractors submitting bids for the second phase will let the Architect know whether a partial opening for the 2005 presidential inauguration is feasible within budget.