كليدواژه :
ديوار برشي مركب , بازشو , برش گير , شكل پذيري , روش اجزاي محدود
چكيده فارسي :
ديوارهاي برشي سيستمي مقاوم در برابر نيروهاي جانبي همچون باد و زلزله مي باشند. با توجه به شكل پذيري و مقاومت جانبي مناسبي كه ديوارهاي برشي فولادي دارند، اين نوع ديوارها در دهه هاي اخير مورد توجه مهندسين و محققين قرار گرفته اند. در صورتيكه تسليم برشي قبل از كمانش ورق جان ديوار رخ دهد، قابليت جذب انرژي ديوار بيشتر خواهد شد. تقويت ورق جان ديوار برشي فولادي موجب تسليم برشي قبل از كمانش ورق مي گردد. بمنظور تقويت ورق ديوار مي توان از سخت كننده هاي فولادي و يا لايه اي از بتن استفاده كرد. ديوار برشي فولادي كه از يك يا دو لايه بتني جهت افزايش مقاومت خارج از صفحه آن استفاده شود، را ديوار برشي مركب مي گويند. با توجه به مطالعات اندكي كه در زمينه اين نوع ديوارها انجام گرفته است، در اين مطالعه به بررسي اثر بازشو و فواصل برش گيرها در رفتار ديوار برشي مركب پرداخته خواهد شد. ابتدا يك ديوار برشي مركب براي ساختمان 10 طبقه طراحي شده و پس از انتخاب طبقه فوقاني آن و ساخت چندين مدل اجزاي محدود در نرم افزار Abaqus، به بررسي آنها پرداخته شده است. نتايج نشان مي دهد كه برخلاف ديوار برشي فولادي كه بازشو در مركز نسبت به كناره ديوار بيشتر مقاومت را كاهش مي دهد، بازشو در گوشه هاي ديوار برشي مركب نسبت به ميانه آن باعث كاهش مقاومت مي شود. همچنين با كاهش فاصله بين برش گيرها ظرفيت ديوار برشي مركب افزايش مي يابد.
چكيده لاتين :
Shear walls are resistant to lateral forces such as wind and earthquake. In recent decades, steel shear walls were regarded because of proper ductility and high strength. If the shear yielding occurs before buckling of web plate of wall, the wall will absorb more energy. Reinforcing steel plate shear wall would cause the occurrence of shear yielding before buckling. In order to strengthen the wall, steel stiffeners or one layer of concrete can be used. Steel shear walls with a layer of concrete are called composite shear wall which have increased out of plane strength. Composite shear walls consist of a thin steel plate, two columns and two horizontal floor beams with one or two concrete layers. Considering the few studies that have been carried out on this type of walls, in this study, the effect of opening and stud spacing will be discussed in the behavior of the composite shear wall. Firstly, a 10-story building with composite shear wall is designed. Thereafter, upper floor is selected and finite element models of this floor are modeled with ABAQUS. The models have one bay and one story with clear span and clear height of 3 m. Beams and columns are from IPB280 and the thickness of web plate and concrete layer are 2 and 100 mm, respectively. It should be mentioned that to prevent local buckling of column flange at the beam-column connection, in line with beam flange, continuity plate is considered. To be ensured about the accuracy of the finite element model and ability of ABAQUS to estimate the actual behavior of shear walls accurately, several shear walls were modeled and analyzed, and their results were compared with the results of available tests in the previous studies (Lubell’s test and Valizadeh’s experimental model). Results show that there is little difference between the experimental results and finite element results. So by taking a little difference, it can be concluded that the finite element results are acceptable.
In order to compare the results of finite element models of composite and steel shear walls with steel moment frame, boundary elements are considered to be similar with the loads in all three models. Comparing the results, it is obvious that, on a constant displacement, the base shear in the steel shear wall is about 120% more than moment frame. Also, base shear in composite shear wall is 23% more than steel shear wall.
Considering the results, it is evident that by reducing the distance between the studs, wall strength increases. Also, increasing web plate thickness may cause the increases in the capacity of the composite shear walls. Presence of opening has always been a reason to decrease the resistance of composite shear walls. Opening at the sides and corners further reduces the resistance. This is unlike steel shear walls. At the end of this paper, effect of the stud positions on the composite shear wall behavior is investigated. Results indicated that the specimen with studs closer to the external environment, will increase the resistance of composite shear wall
