Study On The Mechanical Behaviors Of New Type Single-web Shoulder Beam With Two Concrete-filled Steel Tube Columns

Concrete-filled tube columns have been widely used in civil engineering recent years. By preliminary statistics, over 1000 Concrete-filled tube columns were used in workshop of Baosteel Company, such as 1580 hot-rolled plants, 1420/1550 cold-rolled plants, and the 2^nd steelmaking plants. However, a lot of problems of shoulder beams appeared after used for a few of years. For example, the bolts in the connection of column and shoulder beam were broken, and the backing plates were displaced. In some case, the damaged bolts and backing plates might fall. These problems were mainly caused by dislocation of the crane beams and settlement of the columns. As the problems were difficult to overcome, improvement on the details of shoulder beam was undertaken in the Tenth Five Year Plan of Baosteel Company. Due to the lack of analysis and design method on this new type shoulder beam, study was carried out in this paper.Firstly, a nonlinear finite element numerical model was established by program ANSYS, a shoulder beam joint was modeled and compared with test results to verify the efficiency of the numerical model. Then a typical detail of new type of shoulder beam was obtained from the present plants in Baosteel Company and was analyzed under monotonic loading, According to the numerical result, the bearing capacity of the shoulder beam, the distribution of stress, and the failure modes were given. After that, a parametric study was carried out on three main factors (height to span ratio of shoulder beam, the section height ratio of upper column to shoulder beam, and height to thickness ratio of shoulder beam) to find out their influences on bearing capacity and failure modes.At the end of the paper, the design method was discussed on this new type of shoulder beams. The result revealed that the traditional design method would lead to very conservative in calculating bearing capacity.