Snap-Through Buckling Problem of Spherical Shell Structure

This paper presents results of a numerical study on the nonlinear behavior of shells undergoing snap-through instability. This research investigates the problem of snap-through buckling of spherical shells applying nonlinear finite element analysis utilizing ANSYS Program. The shell structure was modeled by axisymmetric thin shell of finite elements. Shells undergoing snap-through buckling meet with significant geometric change of their physical configuration, i.e. enduring large deflections during their deformation process. Therefore snap-through buckling of shells basically is a nonlinear problem. Nonlinear numerical operations need to be applied in their analysis. The problem was solved by a scheme of incremental iterative procedures applying Newton-Raphson method in combination with the known line search as well as the arc- length methods. The effects of thickness and depth variation of the shell is taken care of by considering their geometrical parameter l. The results of this study reveal that spherical shell structures subjected to pressure loading experience snap-through instability for values of l≥2.15. A form of ‘turn-back\u27 of the load-displacement curve took place at load levels prior to the achievement of the critical point. This phenomenon was observed for values of l=5.0 to l=7.0

Pemodelan Retak Pada Struktur Beton Bertulang

. This paper presents a crack model for reinforced concrete structures by using nonlinear finite element method. The crack model used in this study is a discrete crack to simulate strain discontinuity, Discrete cracks are inserted into the structure when the principal tensile stress of nodes have reached the tensile strength of concrete. Insertion of discrete cracks into the structure is only performed when resulting stress combinations are dominated by normal tension stress. Nevertheless, if the principle tension stress on a Gauss point has exceeded the tensile strength of concrete, the craks is treated as a smeared crack with a change in material behavior from one isotropic to another orthotropic character. To find the appropriate direction and pattern of cracks, insertion of discrete cracks into the structure is not only performed by node separation at nodes which have reached the tensile strength of concrete, but also by rotation of the crack perpendicular to the direction of the principle tension stress and dragging the crack-tip node as far as the crack has propagated. Some specimens with different cases e.i Beam J4 (Burns and Siess 1962), Beam OA (Bresler dan Scordelis 1963) and Beam A4 (Ahmad et al. 1986) were analyzed to validate the model. The model is not only able to shows that the structure response is very close to the experimental test, but also can describe the proper crack pattern

Perancangan Struktur Hotel Ibis Budget Semarang

Structural Design of Ibis Budget Hotel Semarang was designed to comply with SNI 2847-2013 and SNI 1726-2012. Seismic analysis was conducted using dynamic respons spectrum method. The building was designed to be located in zone 4 Indonesian seismic vurnability map meaning that it can experience large earthquake acceleration. Hence the building must be designed as an earthquake-resistant structures. This building was designed as special moment resisting frame systems (SMRFS). The frame system was composed of beams and columns. The columns were designed to be stronger than the beams (strong column-weak beam concept). The concrete was of f'c 29,05 MPa, and the steel reinforcement of the longitudinal bar was fy 400 MPa. The Structure analysis was conducted using an analysis structure program to model the structure and calculate the internal forces on the structure. Failure at the beam-column joint was avoided by designing plastic hinges to occur at the beam ends and at the top base columns connected to foundation

Perencanaan Struktur Hotel Grandhika Semarang

Perencanaan Struktur Hotel Grandhika Semarang ini direncanakan menggunakan metode Sistem Rangka Gedung berupa Sistem Rangka Pemikul Momen Khusus (SRPMK) pada zonasi gempa wilayah Kota Semarang. Pemilihan SRPMK diharapkan struktur gedung memiliki tingkat daktilitas tinggi. Struktur daktail yaitu struktur yang mampu mengalami simpangan pasca elastis yang besar secara berulang kali dan bolak-Balik akibat gempa yang menyebabkan terjadinya pelelehan pertama dan mampu mempertahankan kekuatan struktur sehingga struktur tetap berdiri walaupun berada diambang keruntuhan. Sistem ini direncanakan menggunakan konsep disain kapasitas berupa kolom kuat balok lemah. Sehingga struktur kolom dibuat lebih kuat dari struktur balok, agar pada bagian balok terjadi sendi plastis terlebih dahulu. Sehingga bangunan ini tidak sampai mengalami keruntuhan total pada saat terjadi gempa kuat. Join – join pada hubungan balok – kolom juga didisain agar tidak terjadi keruntuhan terlebih dahulu. Analisis struktur gedung ini berdasarkan pada SNI 03-1726-2012 dan dibantu menggunakan program SAP2000 v15 untuk mengetahui periode getar struktur dan gaya – gaya dalam yang bekerja pada struktur tersebut. Periode getar struktur pada SRPMK harus dibatasi agar struktur tidak terlalu fleksibel. Dari konsep desain kapasitas tersebut akan diperoleh detail penulangan yang benar sesuai metode SRPMK yang digunakan

Studi Komparasi Antara Pracetak Masif Dan Fly Slab Studi Kasus : Struktur Gedung Rusunawa Surakarta

Fly slab is one of the precast concrete slab technological development that has been researched and patented by Ir . Sulistyana in 2011. The concept is how to reduce the mass of precast concrete slab with makes ribs on the concrete slab. To minimize the volume of concrete plate and while maintaining tensile area to makes the style transfer mechanism of concrete to reinforcement or otherwise, are expected to reduce the mass of the structure without reducing strength.Comparative study will be conducted in the final project based on Planning of Building Construction Rusunawa in Surakarta, Central Java 2013. This comparative study is done by compare the results of the structural design Rusunawa existing Surakarta and ready to build using conventional precast concrete massive, with a new structure plan Rusunawa Surakarta with using fly slab as material plate, beam and column structural elements using conventional concrete.Based on the analysis results, showed reduction in the volume of concrete and reinforcement elements beam and coloumn Rusunawa Surakarta structure is 20,25% and 6,3 %. Reduction reaction in the vertical structure of the Rusunawa Building in Surakarta is 16,93%

Perancangan Struktur Hotel Amaris Simpang Lima Semarang

Structural Design of Amaris Hotel Simpang Lima Semarang designed with SNI 2847-2013 and SNI 1726-2012. Seismic analysis using dynamic respons spectrum method. Seismic forces calculated based on area of the earthquake zone 4 as the region has a fairly large earthquake acceleration, so it must be designed earthquake-resistant structures. Included in Seismic Design Criteria Type D so that the planning system used method with special moment resisting frames system (SMRFS). Frame system is composed of a framework of beams and columns, where the columns are made stronger than the beam (strong column weak beam). To avoid failure of the structure at the beam-column joint, plastic form joint is planned to occur in the beams and columns only occur at the top of the column foundation. Structure analysis using anayisis structure program to help modeling the structure and determine the forces acting on the structure. Materials used are concrete f'c 25 MPa, where as for steel reinforcement plates and stirrup fy 240 MPa and longitudinal bar fy 400 MPa