Busan Cinema Center has the Longest Cantilever Roof in the World
Busan Cinema Center is a landmark feature of Busan and is a dedicated theatre for the BIFF (Busan International Film Festival), which is one of the top film festivals in Asia. The building incorporates a theatre, indoor and outdoor cinemas, convention halls, office spaces, creative studios, and dining areas in a mixture of sheltered and linked indoor and outdoor public spaces. The design of these spaces supports a flexible and hybrid functionality that can be used both during the annual festival period and a day- to-day use without interruption. The building is designed by Coop Himmelb(l)au, the world famous architects from Austria, and Daesung C.P Engineering adopted Tekla’s Building Information Modeling (BIM) software to produce the detailed shop drawing.
The longest cantilevered roof in the world
The essence of Dureraum’s beauty is its super-sized roof known as the Big Roof, which is 163 metres long and 60 metres wide with an 85 metres cantilever portion and weighs 6,376 (metric) tons, making it the longest cantilevered roof in the world. Using the Double Cone as its pillar, the Big Roof stands 165 metres high and supports a facility 21 metres above the ground. The front and back of the Big Roof were completed on the ground level, and were hoisted up on a tower crane before being attached where the Double Cone is supporting the structure.
Accurate Camber Value
The underside of the Big Roof is designed as a rolling cloud (free curved surface shape), and the top of Big Roof is a plane structure having a circular-shaped opening. The cambering function in Tekla let the team apply accurate camber value to the Big Roof. “The most challenging part was to put an accurate camber value considered the deflection of the cantilever because of its self-load after construction. Tekla’s BIM software showed all aspects of the model by setting multiple views and it decreased the number of detailing errors. We could do this with 2D shop drawing, but it is time-consuming and it also contains too many errors, but with Tekla we saved time and money,” said Donghyuk Lee, Drawing office manager of Daesung C.P Engineering. The roof of the Busan Cinema Center (South Korea) features a cantilever that extends 85 metres (278 ft 10.45 in) from its single cone-shaped column support.
Lift up Method
When the ceremony was held to celebrate the completion of the framework of the Big Roof, it drew attention for applying the Lift-up method to the architecture. According to HanJin Heavy Industries (Constructor of the Busan Cinema Center), the lift-up method for the longest truss structure was new and advanced.
From Conceptual Design To Detailed Design
The Double Cone is the only vertical structural support for the large cantilevered roof acting as a large, singular column as an exposed structure. Therefore, it was significant to set up the direction of each steel frame’s face. “In the conceptual design phase, we underwent trial and error to set up the modeling direction of each diagonal steel member. The Double Cone consists of three different circle sizes and the steel members of each have different angles of rotation. We came up with an idea to create a beveled central point with NEC (New Engineering Consultants) technical support. One very challenging aspect of the project was to apply accurate angular values to all the members because each inner side has a different angular value with the beveled central point as the center. However, Tekla’s realistic simulation allowed us to detect, prevent clash, and complete this work with much less time and without errors,” said Donghyuk Lee, Drawing office Manager of Daesung C.P Engineering.
Deciding The Division Point
Tekla improves the collaboration and communication between the constructor, fabricator, and shop detailer, and thus fulfills the user’s needs more accurately. The values of centre of gravity from Tekla improve the efficiency of operation of tower crane in the construction site.
Significant Increase In Accuracy
Double Cone and steel work ramp (Pedestrian overpasses) have a streamlined shape, all their structural steel members have different angle of rotation. Thus, it is impossible to draw the coordinates of the structural steel members on the execution drawing with 2D shop drawing. “We were able to improve the accuracy with minimised errors by inputting accurate data to each member through Tekla 3D modeling. Tekla contributed to improvement of the detailing quality and kept the model and drawings consistent when changes happened without errors in the fabrication and erection. Tekla is the optimum solution to increase work efficiency,” said Byungwook Kim, Project delivery Director of Daesung C.P Engineering.