Structural engineers are using building information modeling in greater numbers, according to a recent survey. Yet few firms report that they are sharing BIMs with contractors.
Two-thirds of the responding structural engineers surveyed last year say they are using BIM, compared with one-third in 2008. The fifth annual BIM survey, conducted by the BIM committee of the Structural Engineering Institute (SEI) and the Council of American Structural Engineers (CASE), with the Structural Engineers Association of Texas, went to more than 20,000 structural firms. The response rate was about 5%.
"The majority of the respondents are not sharing their structural BIMs with contractors," says Will Ikerd, founder of the BIM and structural consulting firm that bears his name. "Many of them cite liability concerns as the reason," adds Ikerd, who conducted the surveys as co-chair of the SEI-CASE BIM committee.
Most respondents use BIM for steel structures. But the use of BIM for cast-in-place concrete structures is growing, with 10% of the firms reporting they use BIM for concrete. Five years ago, few firms created concrete BIMs.
Only 20% of the respondents said they charge an extra fee for BIM; 75.2% said they do not. And more than 75% of the firms said BIM training is either horrible, nonexistent or only moderately effective.
The deliverable is still 2D drawings, in the form of a pdf. "The majority of professionals are not doing model-based delivery," says Ikerd.
At a May 6 BIM discussion forum, organized by the Structural Engineers Association of New York, attendees reported many problems associated with BIM use. A big issue is the need to build, maintain and update a separate structural analysis model and a BIM for each job.
A seamless back-and-forth link between the structural analysis model and the BIM is not yet real, agreed engineers. "There are hundreds of bugs and a lot lost in translation—such as entire floor slabs," said one engineer. "It's not an exact science yet," said another.