A new survey of the world's largest construction companies shows that foreign markets -- particularly developing nations -- have become a staple of the building giants but that non-U.S. firms are taking a bigger share of the business.

American firms captured the largest volume among the top 200 companies last year but only 5 U.S. firms were among the top 20. Moreover, the American companies are making a poor showing abroad this year, which is not reflected in the survey.

U.S. builders, "bombarded with an array of tax, regulatory and export financing roadblocks," are finding it increasingly difficult to compete, according to the survey by Engineering News-Record to be published today.

The magazine, published by McGraw-Hill, prepared the Top 200 survey in conjunction with the University of Florida's School of Business Construction. It is the first such compilation of data ever published.

Not surprisingly, the California based Bechtel Group showed up at the top of the Engineering News-Record survey, with a 1978 contract volume of $4.6 billion -- nearly $4 billion of which came from overseas building.

Bechtel is one of the largest corporations in the world and one of a handful of business giants whose stock is controlled privately. Business statistics on Bechtel are not regularly published for public study.

The United States is well represented in the Top 10 with half of the companies but has no firms among the next 10 largest. Overall the 10 largest captured 38 percent of foreign contracts with the U.S. companies taking 55 percent of contracts awarded those firms.

Close to half the $105 billion of new work signed up by the 200 contractors in 1978 came from countries outside their own.

In addition to Bechtel, other companies on the list of the 10 largest are (with foreign contract volume in 1978);

C-E Lummus, a subsidiary of Combustion Engineering Inc., U.S.( $3 billion).

Davy Corp. Ltd., Britain ($2.1 billion).

Hyundal Construction Co. Ltd., South Korea ($1.9 billion).

Phillip Holzmann AG, West Germany ($1.5 billion).

Fluor Corp., U.S. ($1.5 billion).

Pullman Kellogg Division, Pullman Inc., U.S. ($1.5 billion).

HOCHTLEF AG, West Germany ($1.3 billion).

Royal Volker Stevin NV, The Netherlands ( $975 million).

Foster Wheeler Corp., U.S. ( $843 million).

A Subsidiary of International Bank of Washington owns about 10 percent of Foster Wheeler's stock. The only other area business operation in the Top 200 list is Dynalectron Corp., of McLean, with overseas contracts last year of $48 million -- ranking its 126th largest.

According to Engineering News Record, four South Korean firms are among the 20 largest international builders. However, rising Korean wage rates have threatened the current competitive edge -- forcing Korean firms to seek Pakistan and Filipino workers.

Mideast contracts have dropped sharply this year for the U.S. firms, the magazine stated.

Most foreign work for the construction firms comes from prime building contracts and high-technology process plants, as well as professional construction management services.